Good morning on the first day of 2013!
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
556 AM AST TUE JAN 1 2013
.SYNOPSIS...A MID TO UPPER LEVEL RIDGE WILL EXTEND ACROSS THE
LOCAL AREA FOR THE NEXT SEVERAL DAYS...RESULTING IN A GENERALLY
FAIR WEATHER PATTERN ACROSS THE LOCAL ISLANDS.
&&
.DISCUSSION...AFOREMENTIONED MID TO UPPER LEVEL RIDGE WILL EXTEND
ACROSS THE LOCAL AREA FOR THE NEXT SEVERAL DAYS...RESULTING IN A
GENERALLY FAIR WEATHER PATTERN ACROSS THE LOCAL ISLANDS. FOR
TODAY AND TONIGHT AND LINGERING THROUGH WEDNESDAY...THE REMNANTS
OF THE OLD FRONTAL BOUNDARY WILL REMAIN NEAR OR ACROSS THE
FA...RESULTING IN SOME CLOUDINESS AND A FEW SHOWERS. LITTLE CHANGE
EXPECTED THEREAFTER THROUGH THE END OF THE WEEK...AS BANDS AND
PATCHES OF MOISTURE MOVE ACROSS THE LOCAL AREA FROM TIME TO
TIME...RESULTING IN INTERVALS OF CLOUDINESS AND A FEW PASSING
SHOWERS OVER PARTS OF THE LOCAL ISLANDS. SURFACE HIGH PRESSURE
OVER THE SOUTHWEST ATLANTIC WILL MOVE SLOWLY EAST SOUTHEAST
THROUGH THURSDAY...MAINTAINING MODERATE TO FRESH...AND LOCALLY
STRONG TRADE WINDS ACROSS THE FA.
&&
.AVIATION...VFR CONDS AT LCL TAF SITES THRU WED XCP BRIEF MVFR
IN ISOLD SHRA. LLVL WIND MAINLY E 15-25 KT TO FL150.
&&
.MARINE...SURFACE HIGH PRESSURE LOCATED OVER THE SOUTHWEST
ATLANTIC WILL MOVE SLOWLY EAST SOUTHEAST THROUGH THURSDAY...
MAINTAINING MODERATE TO FRESH...AND LOCALLY STRONG TRADE WINDS
ACROSS THE REGIONAL WATERS. LARGE...LONG PERIOD NORTH-NORTHWEST
SWELLS WILL CONTINUE TO BUILD ACROSS THE LOCAL ATLANTIC WATERS AND
THE CARIBBEAN PASSAGES TODAY THROUGH TONIGHT...THEN CONTINUE
THROUGH AT LEAST THURSDAY MORNING. THESE SWELLS WILL RESULT IN
INCREASINGLY ROUGH AND HAZARDOUS MARINE CONDITIONS. A SMALL CRAFT
ADVISORY IS IN EFFECT OR WILL GO INTO EFFECT LATE THIS MORNING FOR
MOST OF THE LOCAL COASTAL WATERS.
IN ADDITION...THESE LARGE...LONG PERIOD NORTH-NORTHWEST SWELLS
WILL AFFECT THE ATLANTIC COASTLINES OF PUERTO RICO...CULEBRA AND
THE NORTHERN U.S. VIRGIN ISLANDS...AND WILL PRODUCE LARGE
BREAKING WAVES AND FREQUENT RIP CURRENTS...RESULTING IN DANGEROUS
SURF CONDITIONS. A HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 3 PM
AST WEDNESDAY FOR THE NORTHWEST THROUGH NORTHEAST COASTS OF PUERTO
RICO...CULEBRA AND THE NORTHERN U.S. VIRGIN ISLANDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 82 72 81 73 / 50 20 20 10
STT 84 73 85 75 / 40 20 20 10
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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
351 PM AST SAT JAN 19 2013
.SYNOPSIS...AN ELONGATED MID TO UPPER LEVEL RIDGE ACROSS THE
CENTRAL ATLANTIC INTO THE EASTERN CARIBBEAN WILL REMAIN THE MAIN
WEATHER FEATURE LOCALLY FOR THE NEXT SEVERAL DAYS BEFORE
WEAKENING LATE IN THE WEEK...AS A POLAR TROUGH AMPLIFIES ACROSS
NORTH AMERICA AND THE WESTERN ATLANTIC.
&&
.DISCUSSION...THE MID TO UPPER LEVEL RIDGE WILL REMAIN THE MAIN
WEATHER FEATURE LOCALLY FOR THE NEXT SEVERAL DAYS...PRODUCING A
GENERALLY FAIR AND MAINLY DRY WEATHER PATTERN ACROSS THE LOCAL
AREA. HOWEVER...LOW LEVEL MOISTURE CONFINED BELOW 800/750 HPA
WILL CONTINUE TO MOVE ACROSS THE LOCAL AREA FROM TIME TO TIME AND
WILL COMBINE WITH LOCAL EFFECTS TO RESULT IN INTERVALS OF
CLOUDINESS AND A FEW SHOWERS EACH DAY. DURING THE EARLY TO MID
PART OF NEXT WEEK...THE AFOREMENTIONED POLAR TROUGH WILL SUSTAIN
A SURFACE FRONT ACROSS THE WESTERN ATLANTIC...WITH AN INVERTED
TROUGH POSSIBLY REACHING THE EASTERN CARIBBEAN. UNDER INFLUENCE
OF THIS INVERTED TROUGH WINDS WILL VEER TO THE SOUTHEAST...
RESULTING IN A WARMING TREND ACROSS THE LOCAL ISLANDS.
&&
.AVIATION...VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS. CIGS
WILL BE MAINLY BETWEEN FL050-070 UNTIL ABOUT 19/23Z. WINDS WILL
BE FROM THE EAST TO EAST NORTHEAST AT 10-15 KNOTS WITH A FEW
HIGHER GUSTS...DECREASING OVERNIGHT. PASSING ISOLATED SHOWERS MAY
CAUSE SOME VCSH ACROSS THE USVI/BVI...TJSJ...AND TJBQ.
&&
.MARINE...EXPECT WINDS OF 17 KNOTS OR LESS AND SEAS OF 6 FEET OR
LESS ACROSS THE REGIONAL WATERS THROUGH AT LEAST MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 83 73 83 / 40 40 20 20
STT 72 85 72 85 / 30 30 20 20
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
525 AM AST SUN JAN 20 2013
.SYNOPSIS...AN ELONGATED MID TO UPPER LEVEL RIDGE ACROSS THE
CENTRAL ATLANTIC INTO THE EASTERN CARIBBEAN WILL CONTINUE TO
SLOWLY WEAKEN OVER THE NEXT FEW DAYS...AS POLAR TROUGH AMPLIFIES
ACROSS NORTH AMERICA AND THE WESTERN ATLANTIC.
&&
.DISCUSSION...A GENERALLY FAIR AND MAINLY DRY WEATHER PATTERN
WILL CONTINUE TO PREVAIL OVER THE NEXT SEVERAL DAYS AS AN
ELONGATED MID TO UPPER LEVEL RIDGE ACROSS THE CENTRAL ATLANTIC
INTO THE EASTERN CARIBBEAN REMAINS THE MAIN WEATHER FEATURE.
HOWEVER...LOW LEVEL MOISTURE CONFINED BETWEEN 800/750 HPA WILL
CONTINUE TO MOVE ACROSS THE LOCAL AREA FROM TIME TO TIME...AND
WILL COMBINE WITH LOCAL EFFECTS TO RESULT IN INTERVALS OF
CLOUDINESS AND A FEW SHOWERS EACH DAY. THE AFOREMENTIONED POLAR
TROUGH WILL SUSTAIN A SURFACE FRONT ACROSS THE WESTERN ATLANTIC
EARLY THIS WEEK...WITH AN INVERTED TROUGH REACHING THE EASTERN
CARIBBEAN BY MID WEEK. UNDER INFLUENCE OF THIS INVERTED TROUGH
THE WINDS WILL VEER TO THE SOUTHEAST ON TUESDAY...RESULTING IN
A WARMING TREND ACROSS THE LOCAL ISLANDS.
&&
.AVIATION...CIGS BKN040 WRN PR WITH A FEW LIGHT SHOWERS POSSIBLE.
TJSJ...USVI AND LEEWARD ISLANDS TERMINALS WILL ONLY HAVE A FEW
CLOUDS. ENE WINDS 12G16KT BCMG LIGHT AND VARIABLE AT NIGHT.
&&
.MARINE...WINDS OF 17 KNOTS OR LESS AND SEAS OF UP TO 6 FEET IN
NORTH SWELLS ARE EXPECTED ACROSS THE REGIONAL WATERS THROUGH AT
LEAST MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 83 73 / 30 20 20 20
STT 84 75 85 75 / 10 20 20 20
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
330 PM AST SUN JAN 20 2013
.SYNOPSIS...AN ELONGATED MID TO UPPER LEVEL RIDGE ACROSS THE
CENTRAL ATLANTIC INTO THE EASTERN CARIBBEAN WILL REMAIN THE MAIN
WEATHER FEATURE LOCALLY FOR THE NEXT SEVERAL DAYS BEFORE WEAKENING
LATE IN THE WEEK...AS A POLAR TROUGH AMPLIFIES ACROSS NORTH
AMERICA AND THE WESTERN ATLANTIC.
&&
.DISCUSSION...THE MID TO UPPER LEVEL RIDGE WILL REMAIN THE MAIN
WEATHER FEATURE LOCALLY FOR THE NEXT SEVERAL DAYS...PRODUCING A
GENERALLY FAIR AND MAINLY DRY WEATHER PATTERN ACROSS THE LOCAL
AREA. HOWEVER...LOW LEVEL MOISTURE CONFINED BELOW 800/750 HPA
WILL CONTINUE TO MOVE ACROSS THE LOCAL AREA FROM TIME TO TIME AND
WILL COMBINE WITH LOCAL EFFECTS TO RESULT IN INTERVALS OF
CLOUDINESS AND A FEW SHOWERS EACH DAY. DURING THE WEEK...THE
AFOREMENTIONED POLAR TROUGH WILL SUSTAIN A SURFACE FRONT MOVING
EAST SOUTHEAST ACROSS THE WESTERN ATLANTIC...WITH AN INVERTED
TROUGH POSSIBLY REACHING THE EASTERN CARIBBEAN. UNDER INFLUENCE OF
THIS INVERTED TROUGH...WINDS WILL GRADUALLY VEER TO THE
SOUTHEAST...RESULTING IN A WARMING TREND ACROSS THE LOCAL
ISLANDS.
ON A PERSONAL NOTE...TODAY MARKS MY LAST OPERATIONAL SHIFT HERE
AT WFO SAN JUAN AFTER 18+ YEARS...AS WE RETURN TO NEW ENGLAND.
THROUGH THE YEARS...IT HAS BEEN BOTH A PLEASURE AND HONOR FOR ME
TO WORK WITH SOME OF THE FINEST...MOST TALENTED AND DEDICATED
EMPLOYEES IN THE NATIONAL WEATHER SERVICE AND TO SERVE THE
RESIDENTS AND VISITORS OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS.
THANK YOU./BCS
&&
.AVIATION...EXPECT PREVAILING VFR CONDITIONS TO CONTINUE ACROSS
THE LOCAL ISLANDS AND AT ALL TAF SITES DURING THE NEXT 24 HOURS.
HOWEVER...BRIEF MVFR CONDITIONS AND LOCAL MOUNTAIN OBSCURATIONS
ARE POSSIBLE IN ISOLATED PASSING SHOWERS.
&&
.MARINE...EXPECT WINDS OF 17 KNOTS OR LESS AND SEAS OF 6 FEET OR
LESS ACROSS THE REGIONAL WATERS THROUGH AT LEAST TUESDAY. SMALL
BOAT OPERATORS SHOULD EXERCISE CAUTION ACROSS PARTS OF THE LOCAL
WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 83 73 85 / 20 20 20 20
STT 75 85 75 85 / 20 20 20 20
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
435 AM AST MON JAN 21 2013
.SYNOPSIS...A GENERALLY FAIR WEATHER PATTERN WILL CONTINUE TO
PREVAIL ACROSS THE LOCAL AREA...AS AN ELONGATED MID TO UPPER
LEVEL RIDGE PERSISTS ACROSS THE TROPICAL ATLANTIC INTO THE
CARIBBEAN.
&&
.DISCUSSION...AN ELONGATED MID TO UPPER LEVEL RIDGE WILL REMAIN
THE MAIN WEATHER FEATURE LOCALLY...WITH ASSOCIATED SUBSIDENCE CAP
WEAKENING DURING THE NEXT FEW DAYS. POLAR TROUGH ACROSS NORTH
AMERICA AND THE WESTERN ATLANTIC WILL CONTINUE TO SUSTAIN A
SURFACE FRONT/SHEAR LINE WHICH IS FORECAST TO MOVE SOUTHEAST WHILE
DISSIPATES NORTH OF THE AREA.
AS A RESULT...OVER THE NEXT FEW DAYS...A GENERALLY FAIR AND MAINLY
STABLE WEATHER PATTERN WILL CONTINUE TO PREVAIL WITH CLOUDINESS
AND PASSING SHOWERS FROM TIME TO TIME..BUT ESPECIALLY MONDAY NIGHT
AND TUESDAY. WINDS WILL VEER TO THE SOUTHEAST ON TUESDAY...AS
SURFACE FRONT/SHEAR LINE MOVES SOUTHEAST. THIS WILL RESULT IN A
WARMING TREND ACROSS THE LOCAL ISLANDS. A WETTER PATTERN COULD BE
EXPECTED DURING THE UPCOMING WEEKEND INTO EARLY NEXT WEEK WHEN A
SURFACE FRONT/SHEAR LINE IS FORECAST TO REACH THE LOCAL AREA.
&&
.AVIATION...VFR CONDS WILL CONTINUE ACROSS THE LCL ISLANDS AND AT
ALL TAF SITES DURG THE NXT 24 HOURS. HOWEVER AT LEAST TIL 21/14Z...
PASSING LIGHT TRADE WINDS SHWRS W/SCT-BKN CLD LAYERS BTW FL020-FL080
WILL REMAIN PSBL OVR THE COASTAL WATERS...AND EN ROUTE TO USVI AND
THE NRN LEEWARD ISLANDS. BRIEF MTN TOP OBSCR ALSO PSBL ACROSS ERN
INTERIOR SECTIONS OF PR WITH PASSING LOW CLDS AND -SHRA. WINDS WILL
CONTINUE FROM THE EAST BTW 10 TO 15 KNOTS BLO FL150 THEN BCM
WESTERLY AND INCR W/HT ABV FL250.
&&
.MARINE...A MODERATE NORTH NORTHWEST SWELL COMBINED WITH EASTERLY
WIND WAVES WILL CREATE HAZARDOUS MARINE CONDITIONS THROUGH THIS
AFTERNOON ACROSS THE OUTER ATLANTIC WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 72 86 72 / 30 20 20 20
STT 85 74 86 76 / 30 20 20 20
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1017 PM AST MON JAN 21 2013
.UPDATE...SATELLITE IMAGERY REVEALS SEVERAL DISTINCT WESTWARD-
MOVING BANDS OF CLOUDS AND SHOWERS THAT ARE INTENSIFYING TONIGHT.
ONE HAS ALREADY PASSED PUERTO RICO...ONE MINOR ONE IS FORMING NEAR
SAINT THOMAS AND THE FINAL BAND IS MOVING THROUGH THE LEEWARD
ISLANDS AT THE MOMENT. THESE ARE EXPECTED TO YIELD SHOWERS FOR
CULEBRA AND EASTERN PUERTO RICO AND PERHAPS VIEQUES
TONIGHT...HAVING ALREADY GIVEN SOME LIGHT SHOWERS TO SAINT JOHN...WITH
MORE COMING EARLY TOMORROW MORNING. SATELLITE PICTURES INDICATE
THE END OF THE BRIGHT BANDS IN INFRA RED IMAGERY UPSTREAM FROM
THE LEEWARD ISLANDS...BUT MODELS SHOW A CONTINUATION OF MOISTURE
AND BANDED SHOWERS. HENCE AM EXPECTING NEW BANDS TO GENERATE AFTER
THESE PASS...AND THEY ARE PASSING RATHER QUICKLY...WITH ONE PATCH
OF CLOUDS MOVING AT ALMOST 30 MPH. ALSO THE 22/00Z SOUNDING SHOWED
TWO DISTINCT CLOUD LAYERS TONIGHT...ONE BASED NEAR 3500 FEET AND
THE OTHER NEAR 8000 FEET...AND IT IS LIKELY THAT IT IS THE MID
LAYER CLOUD THAT IS SHOWING UP SO WELL IN THE INFRA-RED
IMAGERY...HENCE CANNOT PUT TOO MUCH CREDENCE IN ANY DRYING TREND
AT THIS TIME AS LOWER CLOUDS ARE FORMING BEHIND A DRY BAND BEHIND
THE BRIGHTEST ARC OF CLOUDS. HAVE RAISED POPS SOMEWHAT FOR
TONIGHT...TUESDAY AND TUESDAY NIGHT...WITH A SLIGHTLY DRIER BREAK
OF SORTS BEGINNING ON WEDNESDAY NIGHT. LATEST ASCAT PASS ALSO
SHOWED A WEAK WIND SURGE BEHIND THE LAST BAND SHOWN ON INFRA RED
IMAGERY NEAR THE LEEWARD ISLANDS. HAVE NOT SEEN THIS IN
OBSERVATIONS YET...BUT IT IS TOO EARLY. MODELS ARE SHOWING A PICK-
UP IN WINDS LATER AND AM KEEPING THESE VALUES...EXCEPT AM LIMITING
THEM TO 21 KNOTS OR LESS. WINDS MAY EXCEED THIS BRIEFLY...MAINLY
OVER LOCAL WATERS.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
553 AM AST TUE JAN 22 2013
.SYNOPSIS...A RELATIVELY DRY WEATHER PATTERN...TYPICAL FOR THIS TIME
OF THE YEAR...IS EXPECTED TO CONTINUE ACROSS THE LOCAL ISLANDS FOR
THE NEXT SEVERAL DAYS...AS AN ELONGATED MID TO UPPER LEVEL RIDGE
PERSISTS ACROSS THE TROPICAL ATLANTIC INTO THE NORTHEAST CARIBBEAN.
&&
.DISCUSSION...ISOLATED TO LOCALLY SCATTERED PASSING SHOWERS AFFECTED
THE EASTERN SECTIONS OF PUERTO RICO AS WELL AS VIEQUES...CULEBRA AND
THE U.S.V.I. DURING THE OVERNIGHT HOURS. LATEST SATELLITE IMAGES THIS
MORNING DEPICTED FEW WESTWARD-MOVING BANDS OF MOISTURE ACROSS THE
ATLANTIC WATERS EAST OF THE FA. ONE HAS ALREADY MOVED ACROSS PUERTO
RICO OVERNIGHT AND THE OTHER ONE IS JUST ACROSS THE NORTHERN LEEWARD
ISLANDS EARLY IN THE MORNING. THESE BANDS OF MOISTURE ARE
EXPECTED TO PRODUCE SHOWERS ACROSS THE USVI...CULEBRA...VIEQUES AND
EASTERN SECTIONS OF PUERTO RICO THIS MORNING. SUBSIDENCE INVERSION
WILL BE WEAKER TODAY..BUT STILL TOO STRONG FOR DEEP CONVECTION TO
DEVELOP. AFTER THE PASSAGE OF THESE BANDS OF MOISTURE...THE MID TO
UPPER LEVEL RIDGE WILL MAINTAIN A GENERALLY DRY AND STABLE
WEATHER PATTERN FOR THE REST OF THE WORK WEAK...WITH ONLY FEW PATCHES
OF LOW TO MID LEVEL CLOUDS AND ISOLATED QUICK PASSING SHOWERS
EMBEDDED IN THE EASTERLY TRADES AFFECTING PORTIONS OF THE LOCAL ISLANDS.
&&
.AVIATION...OVERALL VFR CONDS EXPECTED ACROSS THE LCL TAF SITES FOR
THE NXT 24 HOURS. A N-S ORIENTED LINE OF CLDS WITH FEW EMBEDDED
SHWRS NOW CROSSING TKPK AND TNCM...WILL CONT EWD AND MAY PRODUCE
BRIEF MVFR IN LOW CIGS AND PASSING SHRA EN ROUTE BTW ERN PR AND NRN
LEEWARDS AT LEAST TIL 22/14Z. ALSO...BRIEF MTN TOP OBSCR WILL REMAIN
PSBL OVR ERN PR DURG THE EARLY MORNING HRS. SFC WND WILL BECOME MORE
SE TODAY AT 10 TO 15 KNOTS...WITH SOME HIGHER GUST NEAR THE PASSING
SHRA. L/LVL WNDS BLO FL150 CONTINUE FM ESE AT 10-15 KTS THEN BACKING
AND BCMG FM W WHILE INCR W/HT ABV FL250.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 72 83 71 / 40 30 20 10
STT 85 75 86 75 / 30 30 20 20
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
257 PM AST TUE JAN 22 2013
.SYNOPSIS...A RELATIVELY DRY WEATHER PATTERN...TYPICAL FOR THIS TIME
OF THE YEAR...IS EXPECTED TO CONTINUE ACROSS THE LOCAL ISLANDS FOR
THE NEXT SEVERAL DAYS...AS AN ELONGATED MID TO UPPER LEVEL RIDGE
PERSISTS ACROSS THE TROPICAL ATLANTIC INTO THE NORTHEAST CARIBBEAN.
&&
.DISCUSSION...VERY LITTLE SHOWER ACTIVITY WAS OBSERVED TODAY AS
LEAST THROUGH 230 PM AST ACROSS PUERTO RICO AND THE U.S. VIRGIN
ISLANDS. A HIGH PRESSURE SYSTEM CONTINUES TO DOMINATE THE LOCAL
REGION. THIS WEATHER PATTERN WILL CONTINUE UNCHANGED DURING THE
NEXT SEVERAL DAYS...AS THIS HIGH PRESSURE REMAINS THE MAIN
FEATURE WHICH DOMINATES THE LOCAL AREA. OVERALL...ATMOSPHERE
REMAINS VERY STABLE...AND DRY...WITH PW VALUES NEAR 1.2 INCHES OR
LESS. PATCHES OF LOW LEVEL MOISTURE WILL MOVE ACROSS THE REGION
FROM TIME TO TIME...BUT SIGNIFICANT RAINFALL ACCUMULATION ARE NOT
EXPECTED. AFOREMENTIONED HIGH PRESSURE SYSTEM WILL WEAKEN SLOWLY
DURING THE NEXT FEW DAYS. HOWEVER...MAINLY DRY AND STABLE
CONDITIONS WILL CONTINUE...AS NO OTHER WEATHER FEATURE ARE
FORECAST TO AFFECT THE REGION IN THE LONG TERM.
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL...EXCEPT SW PUERTO RICO BTWN
22/18-2302Z WHEN AREAS OF MOUNTAIN OBSCURATIONS AND MVFR CONDS DUE
TO CIGS WILL BE POSSIBLE. LLVL WINDS ENE 5-15 KTS UP TO 6 KFT AND
20-25 KT UP TO 10 KFT AND 10-15 KTS 10-20 KFT. MAX WIND WEST NR 55
KT AT 42 KFT.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 72 85 72 82 / 30 20 10 10
STT 75 86 75 85 / 30 20 20 20
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
510 AM AST WED JAN 23 2013
.SYNOPSIS...SUBTROPICAL RIDGE REMAINED POSITIONED ACROSS THE
CENTRAL ATLANTIC. THIS ALONG WITH BROAD TROUGHING ACROSS THE
CENTRAL CARIBBEAN WILL HELP INDUCE MODERATE SOUTHEASTERLY WIND
FLOW ACROSS THE NORTHEAST CARIBBEAN. SATELLITE IMAGERY SHOWED WEAK
CONVERGENCE MOISTURE BANDS BEING TRANSPORTED WESTWARDS ACROSS THE
FORECAST AREAS IN THE PREVAILING EASTERLIES. EXPECT THE ATLANTIC
RIDGE TO REMAIN IN PLACE FOR THE NEXT SEVERAL DAYS AND WILL BE
LATER REINFORCED BY YET ANOTHER AREA OF HIGH PRESSURE WHICH WILL
EXIT THE EASTERN SEABOARD OF THE UNITED STATES ON FRIDAY. MID TO
UPPER LEVEL RIDGE WILL REMAIN ANCHORED ACROSS THE EAST AND
NORTHEAST CARIBBEAN TODAY THROUGH AT LEAST THURSDAY BUT WILL
GRADUALLY ERODE BY FRIDAY AS AN UPPER TROUGH BECOMES AMPLIFIED
ACROSS THE WEST AND SOUTHWEST ATLANTIC.
&&
.DISCUSSION...MOSITURE CONVERGENCE BANDS BEING TRANSPORTED BY THE
MODERATE SOUTHEASTERLY TRADES WILL BRING PERIODS OF PASSING CLOUDS
AND SHOWERS TO PARTS OF THE EAST COASTAL SECTIONS OF THE ISLANDS
DURING THE REST OF THE MORNING HOURS.THIS WILL BE FOLLOWED BY A
GRADUAL CLEARING DURING THE LATE MORNING AND EARLY AFTERNOON.
HOWEVER DIURNAL HEATING AND LOCAL SEA BREEZE VARIATIONS IN SOME
AREAS MAY LEAD TO AFTERNOON SHOWER DEVELOPMENT IN ISOLATED SPOTS
ACROSS THE ISLANDS. IN THE PREVAILING STEERING FLOW...EXPECT
SOME AFTERNOON CONVECTION ACROSS PARTS OF THE WEST AND NORTHWEST
SECTIONS OF PUERTO RICO. RAINFALL AMOUNTS ARE HOWEVER EXPECTED TO
BE MINIMAL AND NOT WIDESPREAD. OVER THE VIRGIN ISLANDS A FEW
SHOWERS MAY FORM ON THE LEE SIDE OF THE ISLANDS AND QUICKLY STREAM
WESTWARD OUT TO THE COASTAL WATERS LEAVING NO SIGNIFICANT AMOUNTS
OF RAINFALL OVER THE ISLANDS. LONG TERM WISE...EXPECT MORE OR LESS
THE SAME TREND TO PERSIST FOR THE NEXT SEVERAL DAYS WITH THE PREVAILING
EASTERLIES BEING THE DRIVING FORCE OF PASSING SHOWERS AND NO SIGNIFICANT
WEATHER FEATURE IN SIGHT FOR THE MOMENT.
&&
.AVIATION...MOSTLY VFR CONDS EXPECTED ACROSS THE LCL FLYING AREA
FOR THE NXT 24 HOURS. HOWEVER...FEW ISOLD SHOWERS WILL CONTINUE
TO MOVE NORTHWESTWARD PRODUCING BRIEF PERIODS OF MVFR CONDS ACROSS
TJSJ...TJNR AND TJPS UNTIL 23/12Z. MOSTLY FAIR WX SKIES WILL ENCOMPASS
THE FLYING AREA FM 23/14Z-24/00Z. HOWEVER...BRIEF MOUNTAIN TOP OBSCURATIONS
IN ERN INTERIOR OR PR AFT 23/16Z DUE TO FEW PASSING SHRA...BUT OVERALL
CONDITIONS WILL REMAIN VFR AT TAF SITES. TJSJ 23/00Z UPPER AIR SOUNDING
AND RADAR VAD WIND PROFILE INDICATED AN EAST SOUTHEAST WIND FLOW UP
TO 20 KNOTS ALL THE WAY FROM THE SURFACE TO 15K FEET...BECOMING WESTERLY
AND INCR ALOFT.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 85 73 83 72 / 30 10 10 20
STT 85 73 84 73 / 20 20 20 30
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
249 PM AST WED JAN 23 2013
.SYNOPSIS...HIGH PRESSURE SYSTEM WILL CONTINUE TO DOMINATE THE
LOCAL AREA NEXT SEVERAL DAYS.
&&
.DISCUSSION...AFTER A CLOUDY MORNING OVER THE AREA...MOSTLY SUNNY
SKIES WITH LITTLE SHOWER ACTIVITY WAS OBSERVED OVER PUERTO RICO
AND THE U.S. VIRGIN ISLANDS THIS AFTERNOON. SOME LIGHT TO MODERATE
SHOWERS DEVELOPED THIS AFTERNOON OVER THE NORTHWEST SECTION OF
PUERTO RICO DUE TO A LITTLE BIT OF INSTABILITY ACROSS THE REGION.
SURFACE WINDS HAVE PREVAILED MAINLY FROM THE SOUTHEAST...WITH SEA
BREEZE VARIATION ACROSS THE LOCAL AREA. AS 230 PM AST...MAXIMUM
TEMPERATURE AT SAN JUAN AIRPORT REACHED 86 DEGREES UNDER THIS
SOUTHEAST WIND FLOW. WINDS WILL INCREASE TOMORROW AND FRIDAY AND
WILL SHIFT TO EAST NORTHEAST...AS A SURFACE HIGH PRESSURE
CURRENTLY OVER THE EASTERN U.S...MOVES OVER THE WESTERN ATLANTIC
NORTH OF THE AREA. OTHER THAN PATCHES OF LOW LEVEL MOISTURE MOVING
ACROSS THE LOCAL ISLANDS FROM TIME TO TIME...NO SIGNIFICANT
WEATHER EVENTS ARE FORECAST TO AFFECT THE REGION IN THE LONG TERM.
&&
.AVIATION...VFR CONDITIONS WITH NO SIG WX. ONSHORE WINDS 12G17KT
DURING THE DAY BECOMING LIGHT/VARIABLE AT NIGHT.
&&
.MARINE...SMALL CRAFT SHOULD EXERCISE CAUTION DUE TO SEAS OF 6
FEET AND WINDS UP TO 18 KTS. A NEW GROUP OF NORTH SWELLS ARE
FORECAST TO AFFECT THE ATLANTIC COASTAL WATERS ON SATURDAY OR
SUNDAY. STAY TUNED FOR FURTHER INFORMATION.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 84 71 84 / 10 10 20 20
STT 73 84 73 85 / 20 20 30 30
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
332 AM AST THU JAN 24 2013
.SYNOPSIS...MID TO UPPER LEVEL RIDGE WILL PERSIST ACROSS THE REGION
FOR THE NEXT SEVERAL DAYS AND THROUGH THE UPCOMING WEEKEND. THIS
WILL THEREFORE HELP MAINTAIN STABLE ATMOSPERIC CONDITIONS ALOFT AND
A FAIRLY STRONG SUBSIDENCE CAP ACROSS THE THE NORTHEASTERN
CARIBBEAN. IN THE LOW LEVELS...THIS IS SUPPORTED BY STRONG HIGH
PRESSURE RIDGE ACROSS THE CENTRAL AND NORTHEAST ATLANTIC. THE
SURFACE RIDGE IS INDUCING A SOUTHEASTERLY WIND FLOW AT THE MOMENT
HOWEVER EXPECT THE TRADE WINDS TO BECOME EASTERLY THROUGHOUT THE DAY
AND INTO THE WEEKEND AS A FRONTAL TROUGH LIFTS NORTHEAST ACROSS WEST
AND CENTRAL ATLANTIC WHILE RIDING THE PERIPHERY OF THE BROAD
ATLANTIC RIDGE...WHICH WILL FURTHER STRENGTHEN OVER THE UPCOMING
WEEKEND. PREVAILING EASTERLIES ARE TO THEN PERSIST THROUGH THE
WEEKEND AND INTO EARLY NEXT WEEK WITH THE LOCAL PRESSURE GRADIENT
FORECAST TO TIGHTEN ACROSS THE REGION THUS INCREASING THE EAST
NORTHEAST TRADE WIND FLOW.
&&
.DISCUSSION...THE PREVAILING LOW LEVEL FLOW WILL CONTINUE TO BRING
OCCASIOAL PATCHES OF SHALLOW MOISITURE CONVERGENCE BANDS ACROSS THE
REGION DURING THE REST OF THE MORNIN HOURS. ACCOMPANYING THESE BANDS
ARE AREAS OF LIGHT TO MODERATE SHOWERS WHICH WILL AFFECT THE COASTAL
WATERS AND PARTS OF THE NORTH AND EAST SECTIONS OF THE ISLANDS.
ONCE AGAIN A GRADUAL CLEARING IS EXPECTED ACROSS THE ISLANDS
THROUGHOUT THE DAY LEAVING MOSTLY FAIR WEATHER SKIES. LATEST GFS
MODEL GUIDANCE INITIALIZED WELL AND CONTINUED TO SUGGEST SIMILAR
WEATHER SCENARIO FOR THE NEXT SEVERAL DAYS INTO THE WEEKEND WITH
MOSTLY FAIR WEATHER SKIES AND ONLY SLIGHT CHANCE OF DAYTIME SHOWER
ACTIVITY WHICH WILL BE MAINLY DUE TO DAYTIME HEATING AND LOCAL SEA
BREEZE EFFECTS IN SOME AREAS. UNDER THE PREVAILING STEERING FLOW...
EXPECT AFTERNOON CONVECTION TO IF ANY TO BE FOCUSED MAINLY
ACROSS PARTS OF THE THE WEST AND NORTHWEST SECTIONS OF PUERTO
RICO. RAINFALL WILL BE VERY LIMITED OVER THE VIRGIN ISLANDS DURING
THE DAY...WITH ONLY A FEW SHOWERS EXPECTED TO FORM IF ANY ON THE
LEE SIDE OF THE ISLANDS.
&&
.AVIATION...MOSTLY VFR CONDITIONS EXPECTED ACROSS THE LOCAL FLYING
AREA FOR THE NEXT 24 HOURS. HOWEVER...FEW ISOLATED SHOWERS WILL
CONTINUE TO MOVE NORTHWESTWARD PRODUCING BRIEF PERIODS OF MVFR
CONDITIONS ACROSS TJSJ UNTIL 24/12Z. DRIER AIR WILL ENCOMPASS THE
AREA AFTER 24/14Z TILL AT LEAST 25/00Z. INCREASING MOUNTAIN
OBSCURATIONS ARE EXPECTED AFTER 24/16Z...BUT PREVAILING CONDITIONS
WILL REMAIN VFR AT TAF SITES. TJSJ 24/00Z SOUNDING INDICATED AN EAST
SOUTHEAST WIND FLOW UP TO 20 KNOTS FROM THE SURFACE TO 10K FEET...
BECOMING NORTHWESTERLY AND STRONGER ALOFT.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 72 83 71 / 30 20 20 30
STT 85 73 85 74 / 30 30 30 30
NATIONAL WEATHER SERVICE SAN JUAN PR
301 PM AST THU JAN 24 2013
.SYNOPSIS...MID LEVEL RIDGE WILL HOLD THROUGH MONDAY THEN FLATTEN
TUESDAY AS CENTRAL ATLANTIC TROUGH AMPLIFIES. THIS WILL HELP PUSH A
WANING FRONT THROUGH THE AREA TUESDAY. HIGH PRESSURE WILL THEN BUILD
ACROSS THE WESTERN ATLANTIC STRENGTHENING THE TRADE WINDS.
&&
.DISCUSSION...PATCHES OF LOW LEVEL MOISTURE MOVED ACROSS THE LOCAL
AREA IN THE MORNING HOURS AND EARLY THIS AFTERNOON. THIS KEPT
SKIES WITH SOME CLOUDS...BUT ONLY FEW PASSING SHOWERS WERE
OBSERVED MAINLY OVER THE COASTAL WATERS. HIGH PRESSURE CONTINUES
TO DOMINATE THE LOCAL AREA...WHICH IS MAINTAINING STABLE
ATMOSPHERIC CONDITIONS WITH LITTLE SHOWER ACTIVITY OVER THE
REGION. PATCHES OF LOW LEVEL MOISTURE WILL CONTINUE TO AFFECT THE
LOCAL AREA FROM TIME TO TIME...AS TRADE WINDS BRING THESE PATCHES
ACROSS THE AREA. NO SIGNIFICANT CHANGES IN THIS WEATHER PATTERN IS
EXPECTED DURING THE NEXT SEVERAL DAYS. IN THE MEANTIME...PRESSURE
GRADIENT WILL TIGHTEN DURING THE WEEKEND...STRENGTHENING THE TRADE
WINDS ACROSS THE REGION.
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS ALL TAF
SITES THROUGH THE FORECAST PERIOD.
&&
.MARINE...SEAS REMAINS MAINLY 2-4 FT EXCEPT 5 FT OFFSHORE ATLC WATERS.
NORTH SWELLS WILL BEGIN IMPACTING ATLANTIC WATERS LATE SATURDAY
WITH SEAS BUILDING SUNDAY. REFER TO LATEST COASTAL WATER FORECAST
FOR LATEST INFORMATION.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 74 83 71 82 / 20 20 30 30
STT 74 85 74 84 / 30 30 30 30
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
518 AM AST FRI JAN 25 2013
.SYNOPSIS...A RELATIVELY DRY WEATHER PATTERN...TYPICAL FOR THIS TIME
OF THE YEAR...IS EXPECTED TO CONTINUE ACROSS THE LOCAL ISLANDS FOR
THE NEXT SEVERAL DAYS...AS A MID LEVEL RIDGE DOMINATES THE LOCAL
REGION.
&&
.DISCUSSION...AS PREVIOUS DAYS...PATCHES OF LOW LEVEL MOISTURE WITH
EMBEDDED ISOLATED SHOWERS MOVED MAINLY ACROSS THE EASTERN SECTIONS
OF PUERTO RICO AS WELL AS ACROSS VIEQUES...CULEBRA AND THE USVI
OVERNIGHT AND EARLY IN THE MORNING. A WEAK EASTERLY PERTURBATION
WILL BRING SOME CLOUDS AND SHOWERS ACROSS THE USVI EARLY THIS
MORNING...AND THEN ACROSS EASTERN PUERTO RICO BY MID MORNING...BUT
NO SIGNIFICANT OR WIDESPREAD PCPN IS EXPECTED. HIGH PRESSURE WILL
CONTINUE TO DOMINATE THE LOCAL AREA...MAINTAINING STABLE
ATMOSPHERIC CONDITIONS OVER THE REGION. HOWEVER...FOR THE
WEEKEND...PATCHES OF LOW LEVEL MOISTURE WILL CONTINUE TO AFFECT
THE LOCAL AREA FROM TIME TO TIME...AS TRADE WINDS BRING THESE
PATCHES ACROSS THE AREA. THE PRESSURE GRADIENT IS EXPECTED TO
TIGHTEN DURING THE WEEKEND...STRENGTHENING THE TRADE WINDS ACROSS
THE LOCAL ISLANDS. THE GFS MODEL GUIDANCE SUGGESTS THAT A SURGE OF
MOISTURE WILL MOVE ACROSS THE LOCAL ISLANDS EARLY SATURDAY AND
SUNDAY...INCREASING THE PWAT VALUE TO AROUND 2.0 INCHES IN
COMPARISON WITH PWAT VALUES NEAR 1.0 INCH FOR THE PAST SEVERAL
DAYS. THIS SURGE OF MOISTURE IS EXPECTED TO MOVE RAPIDLY WESTWARD
IN RESPONSE TO THE EXPECTED INCREASE IN LOW LEVEL WIND SPEED. PWAT
VALUES ARE EXPECTED TO DECREASE AGAIN RAPIDLY BY NEXT WEEK. NO
SIGNIFICANT CHANGES IN THIS WEATHER PATTERN IS EXPECTED DURING THE
NEXT SEVERAL DAYS.
&&
.AVIATION...MOSTLY VFR CONDITIONS THROUGH THE FORECAST PERIOD.
HOWEVER...A WEAK EASTERLY PERTURBATION WILL BRING CLOUDS AND SHOWERS
IN AND AROUND USVI AT 25/06Z...AND THEN SPREADING ACROSS EASTERN PR
ARND 25/09Z AND WESTERN PR AFT 25/14Z. THIS WILL RESULT IN MOUNTAIN
OBSCURATIONS AND BRIEF MVFR. A SECOND BAND OF MOISTURE FOLLOWING
CLOSELY BEHIND WILL BE NOTED IN THE LEEWARD ISLANDS AFT 25/18Z. LLVL
WINDS ENE-E 5-18 KTS UP TO 7 KFT.
&&
.MARINE...SEAS OF 6 FEET OR LESS AND WINDS 16 KNOTS OR LESS ARE
EXPECTED TODAY. THE PRESSURE GRADIENT IS EXPECTED TO
TIGHTEN DURING THE WEEKEND...STRENGTHENING THE TRADE WINDS ACROSS
THE LOCAL ISLANDS. THUS SEAS AND WINDS ARE EXPECTED TO INCREASE
TONIGHT AND DURING THE REST OF THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 71 82 72 / 40 50 40 30
STT 85 74 84 74 / 40 50 40 30
NATIONAL WEATHER SERVICE SAN JUAN PR
309 PM AST FRI JAN 25 2013
.SYNOPSIS...BROAD POLAR TROUGH WILL DOMINATE THE ATLC OVR THE NEXT
SEVEN DAYS. SFC RIDGE TO THE NORTH WILL MAINTAIN MODERATE TRADES
INTO EARLY NEXT WEEK THEN STRENGTHEN AS STRONG HIGH PRES EXITS THE
MID ATLC COAST.
&&
.DISCUSSION...SOMEWHAT COOLER AND WETTER PATTERN APPEARS IN STORE
FOR THE NEXT FIVE DAYS AS LOCAL AREA REMAINS UNDER THE INFLUENCE
OF A BROAD TROUGH ALOFT AND UNDER THE DIVERGENT SIDE OF RIGHT
ENTRACE REGION OF A SUBTROPICAL JET STREAK TO THE NORTH OF PR.
UNDER THE INFLUENCE OF THE BROAD TROUGH ALOFT MODELS KEEP A FAIRLY
WEAK SUBSIDENCE INVERSION WITH BASE OF THE INVERSION NEAR 650 MB.
MODELS SHOW A CLOUDY SHOWERY DAY TOMORROW THE BEST CHANCE FOR
WETTING RAINS IN QUITE SOMETIME. EXPECT A DECREASE IN CVRG SUN
FOLLOWED BY MORE CLOUDS AND SHOWERS MON-WED AS MID LEVEL RIDGE
COLLAPSES AS ADDITIONAL SHORTWAVE ENERGY MOVES ACROSS THE AREA.
SUBTROPICAL JET STREAK SHIFTS SOUTH OF THE AREA WED NIGHT PUTTING
AREA UNDER UPPER LEVEL CONFLUENCE AND CONVERGENT SIDE OF JET
MAXIMA WITH A DRYING TREND EXPECTED STARTING THU AND FOR NEXT
WEEKEND. WINDS WILL ALSO STRENGTHEN MID WEEK AS STRONG HIGH PRES
EXITS THE MID ATLC COAST AND TIGHTENS THE PRES GRADIENT UNDER A
POSITIVE NAO PATTERN.
&&
.AVIATION...MOSTLY VFR CONDITIONS THROUGH THE FORECAST PERIOD.
HOWEVER...PATCHES OF LOW LEVEL MOISTURE WILL BRING CLOUDS AND
SHOWERS IN AND AROUND USVI AT 26/06Z...AND THEN SPREAD ACROSS
EASTERN PR AROUND 26/12Z AND WESTERN PR AROUND 25/18Z. THIS WILL
RESULT IN MOUNTAIN OBSCURATIONS AND BRIEF MVFR CIGS. LOW LEVEL WINDS
WILL CONTINUE MAINLY NORTHEAST 10 TO 15 KT.
&&
.MARINE...NORTH SWELLS WILL CONTINUE TO BUILD OVER THE WEEKEND
WITH SEAS 6-8 FT EXPECTED. SCA`S WERE ALREADY ISSUED AND HIGH SURF
MAY BE REQUIRED TOMORROW. AFTER SWELLS SUBSIDE MON WINDS STRENGTHEN
MID NEXT WEEK WITH ROUGH CONDITIONS EXPECTED ACROSS ATLC COASTAL
WATERS MUCH OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 72 84 72 83 / 70 70 10 10
STT 75 84 75 85 / 60 60 10 10
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
436 AM AST SAT JAN 26 2013
.SYNOPSIS...HIGH PRESSURE MAINTAINS OVER SOUTH AMERICA AND THE
SOUTHEASTERN CARIBBEAN...SHIFTING WEST DURING THE WEEK. A LONG
WAVE TROUGH PASSES TO THE NORTH OF US ON SUNDAY WITH A SECOND
SHORTER WAVE PASSING TUESDAY NIGHT. HIGH PRESSURE THEN ANGLES IN
FROM THE SOUTHWEST WEDNESDAY THROUGH SATURDAY WITH FLOW RETURNING
TO THE WEST NORTHWEST AFTERWARD.
AT MID LEVELS...HIGH PRESSURE CONTINUES OVER THE NORTHEAST
CARIBBEAN THROUGH WEDNESDAY. A TROUGH DIGS INTO THE TROPICAL
CARIBBEAN BETWEEN 40 AND 50 WEST LONGITUDE WITH A TROUGH FORMING
OVER THE LEEWARD ISLANDS AND EXTENDING JUST SOUTH OF SAINT CROIX.
HIGH PRESSURE RETURNS BY LATE WEEK. EXCEPT FOR BRIEF AND WEAK MOISTURE
MONDAY NIGHT...MID LEVELS ARE VERY DRY.
AT LOWER LEVELS...BANDS OF MOISTURE IN THE TRADE WIND FLOW
CONTINUE TO PUSH THROUGH THE AREA THROUGH MONDAY. A WEAK PRE-
FRONTAL BOUNDARY ENTERS THE AREA ON MONDAY HOVERS JUST SOUTH OF
THE AREA AND RETURNS ON THURSDAY NIGHT AS PART OF THE TAIL END OF
THE FRONT. AFTER WHICH BANDS OF TROPICAL MOISTURE IN TRADE WIND
FLOW RESUME.
&&
.DISCUSSION...SHOWERS CROSSED IN PRIMARILY EAST NORTHEAST FLOW
THROUGH NORTHERN AND EASTERN PUERTO RICO LEAVING LIGHT AMOUNTS AND
WET STREETS. BY EARLY MORNING THE LEEWARD ISLANDS WERE STILL
REPORTING LIGHT RAIN AT SAINT MARTIN AND EXTRAPOLATION FROM INFRA
RED SATELLITE IMAGERY SUGGESTS THAT THE BACK EDGE OF THIS FAIRLY
LARGE BAND OF LIGHT TO MODERATE SHOWERS WILL NOT PASS OUT OF
EASTERN PUERTO RICO BEFORE 6 PM AST TODAY. NEVERTHELESS EXPECT MOST
SHOWERS TO BE OVER FOR THE LAND AREAS BY 6 PM AST AND A SOMEWHAT
EARLIER CESSATION IN THE U.S. VIRGIN ISLANDS. MODELS SEEM TO HAVE
A GOOD HANDLE ON THE TIMING OF THE FIRST SEVERAL BANDS OF MOISTURE
WITH THE SECOND PASSING SUNDAY AFTERNOON AND EVENING. AT THIS
POINT THE NAM INTRODUCES VERY DRY AIR...BUT THE GFS CONTINUES WITH
ANOTHER MAXIMUM OF PRECIPITABLE WATER MONDAY AND AGAIN ON
THURSDAY. THIS LATTER SCENARIO OF CONTINUED SHOWERY AND SOMEWHAT
COOL WEATHER SEEMS TO BE A BETTER SOLUTION AND HAVE STAYED CLOSE.
HAVE ALSO NOTED THAT 1000-850 MB THICKNESSES IN THE GFS CONTINUE
TO DECREASE THROUGH WEDNESDAY MORNING BY ABOUT 9 METERS...BUT
RECOVER MOST OF THIS BY FRIDAY. TEMPERATURES AT 600 MB ALSO REACH
THEIR LOWEST LEVEL ON WEDNESDAY WHEN THE FRONT MAKES ITS CLOSEST
APPROACH. ONE NOTABLE EXCEPTION TO THE COOLER SCENARIO IS
SOUTHWEST PUERTO RICO WHICH WILL RUN A LITTLE WARMER THAN NORMAL
DUE TO THE NORTHEAST TO EAST FLOW AND A FEW SPOTS WILL REACH 90
DEGREES BETWEEN NOW AND MONDAY.
&&
.AVIATION...A WEAK TROUGH WITH SHOWERS FOLLOWING WILL PASS OVER
PR/USVI...MAINLY THIS MORNING. TJSJ/TJBQ/TIST/TISX/TNCM/TKPK WILL
SEE AT LEAST SOME SHOWERS IN THEIR IMMEDIATE VCNTY THIS MORNING
THOUGH MVFR CONDS WILL BE BRIEF. DECREASING MOISTURE BY AFTERNOON
WILL REDUCE THEIR NUMBERS TO ISOLATED/SCATTERED...PERSISTING
TONIGHT/SUNDAY. LLVL WINDS BELOW FL100 ESE 16-24 KT TODAY
GRADUALLY BECOMING E-ENE TONIGHT/SUNDAY.
&&
.MARINE...NORTHERLY SWELL WILL RAMP UP TONIGHT AND TOMORROW OVER
THE ATLANTIC WATERS AND SPREAD INTO THE PASSAGES. SWELL WILL
DIMINISH SUNDAY NIGHT WITH A SHORT BREAK IN SMALL CRAFT ADVISORY
CONDITIONS UNTIL SEAS INCREASE AGAIN...MOSTLY DUE TO INCREASED
WINDS FROM THE EAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 72 84 73 / 70 10 10 30
STT 83 71 85 74 / 60 10 10 20
NATIONAL WEATHER SERVICE SAN JUAN PR
307 PM AST SAT JAN 26 2013
...ROUGH SURF CONDITIONS EXPECTED OVER THE WEEKEND...
.NORTH SWELLS WILL CONTINUE TO BUILD ACROSS THE ATLANTIC COASTAL
WATERS TODAY THROUGH SUNDAY AND RESULT IN SIGNIFICANT BREAKING
WAVE ACTION.
PRZ001-002-005-008-010-012-VIZ001-270315-
/O.CON.TJSJ.SU.Y.0004.000000T0000Z-130128T0500Z/
SAN JUAN AND VICINITY-NORTHEAST-NORTH CENTRAL-NORTHWEST-
MAYAGUEZ AND VICINITY-CULEBRA-
ST. THOMAS/ST. JOHN/ADJACENT ISLANDS-
307 PM AST SAT JAN 26 2013
...HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 1 AM AST MONDAY...
A HIGH SURF ADVISORY REMAINS IN EFFECT UNTIL 1 AM AST MONDAY.
* WAVES AND SURF: 6 TO 8 FOOT WAVES WITH BREAKING WAVES OF 11 TO
14 FEET.
* TIMING: TODAY THROUGH SUNDAY EVENING.
* IMPACTS: ROUGH SURF CONDITIONS WITH SCATTERED RIP CURRENTS.
LOCALIZED BEACH EROSION IS ALSO POSSIBLE AT TIMES OF HIGH TIDE.
HERE ARE THE TIMES OF HIGH TIDE:
SAN JUAN: 8:15 PM AST SAT AT 0.86 FEET
ARECIBO: 8:08 PM AST SAT AT 1.01 FEET
MAGENS BAY: 9:43 AM AST SUN AT 1.04 FEET
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A HIGH SURF ADVISORY MEANS THAT HIGH SURF WILL AFFECT BEACHES IN
THE ADVISORY AREA...PRODUCING RIP CURRENTS AND LOCALIZED BEACH
EROSION.
&&
$$
HTTP://WWW.WEATHER.GOV/SANJUAN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
453 AM AST SUN JAN 27 2013
.SYNOPSIS...AT UPPER LEVELS...A JET AND SEVERAL BROAD TROUGHS WILL
BRUSH BY BEFORE HIGH PRESSURE BUILDS OVER THE AREA FROM THE WEST
WEDNESDAY THROUGH SATURDAY. ANOTHER TROUGH WILL PASS BY LATE IN
THE FOLLOWING WEEKEND.
AT MID LEVELS...HIGH PRESSURE WILL REMAIN CLOSE TO THE LOCAL AREA
FOR THE ENTIRE PERIOD. A WEAK TROUGH WILL PASS TO THE EAST FROM
THE NORTH ON WEDNESDAY.
AT LOWER LEVELS...TRADE WIND FLOW WILL CONTINUE DUE TO THE HIGH
PRESSURE THAT REMAINS RIDGED OVER THE AREA FROM WEST TO EAST. HIGH
PRESSURE LEAVING THE EAST COAST OF THE UNITED STATES ON MONDAY
WILL REINFORCE THIS RIDGE AND INCREASE WINDS OVER THE AREA. A
PRE-FRONTAL BOUNDARY WILL PASS THROUGH ON MONDAY FOLLOWED BY A
SHEAR LINE THAT WILL STALL OVER THE ISLAND ON WEDNESDAY BEFORE
RETREATING LATER IN THE WEEK.
&&
.DISCUSSION...SHOWERS WERE MUCH LESS FREQUENT OVER LAND OVERNIGHT
THAN THEY WERE LAST NIGHT. AMOUNTS...WHERE RAIN FELL...WERE VERY
LIGHT. SATELLITE IMAGERY SHOWED THE NEXT BAND OF CLOUDS AND LIGHT
SHOWERS ENTERING THE LEEWARD ISLANDS THIS MORNING AND ARE EXPECTED
IN THE U.S. VIRGIN ISLANDS LATER THIS MORNING AND IN PUERTO RICO
BY THIS AFTERNOON. NEVERTHELESS ONLY ISOLATED SHOWERS ARE EXPECTED
IN THE U.S. VIRGIN ISLANDS THIS MORNING AND IN PUERTO RICO THIS
AFTERNOON WITH BETTER CHANCES TONIGHT IN THE EASTERN PORTION OF
PUERTO RICO. THE APPROACH OF THE PRE-FRONTAL BAND AND THE SHEAR
LINE FROM THE NORTH NORTHWEST WILL ENHANCE THE CLOUDS AND SHOWERS
OVER THE AREA...BUT OVERALL AMOUNTS WILL CONTINUE TO BE SPOTTY AND
LIGHT. BEST DRYING APPEARS TO BE ON SATURDAY...BUT CANNOT SAY WITH
ANY CONFIDENCE DUE TO MODEL VAGARIES THIS FAR OUT IN TIME.
&&
.AVIATION...VFR TO CONT. ISOLD SHRA GIVE MOST TAF SITES AN OUTSIDE
CHC OF MVFR MAINLY DUE LWR CIGS. MOUNTAIN OBSCURATIONS WILL CONT
UNTIL ABOUT 27/18Z IN THE EAST. LLVL WINDS E-ENE 12-22 KT BCMG NE
TONITE/MON.
&&
.MARINE...SEAS SPIKED TO 11 FEET AT BUOY 41043 AND WERE 8.5 FEET
AT THE INNER BUOY 41053 AT 4 AM AST. THIS IS MORE THAN ENOUGH TO
KEEP THE HIGH SURF ADVISORY FOR NOW. THE WAVE WATCH SUGGESTS THAT
SEAS WILL DIMINISH RAPIDLY TODAY AND TOMORROW...AND THIS SEEMS
SPOT ON. SEAS WILL RE-BUILD ON TUESDAY EARLY SO THAT SMALL CRAFT
ADVISORIES WILL BE NEEDED AGAIN IN THE OUTER ATLANTIC WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 83 73 / 10 30 30 30
STT 85 74 85 74 / 10 20 20 40
NATIONAL WEATHER SERVICE SAN JUAN PR
257 PM AST SUN JAN 27 2013
.SYNOPSIS...BROAD TROUGH ALOFT WILL DOMINATE THROUGH TUE THEN PULL
EAST OF 60W WED WITH RIDGING EXPECTED TO BUILD MID TO LATE WEEK
AND HOLD THROUGH NEXT WEEKEND.
&&
.DISCUSSION...UNDER THE INFLUENCE OF UPPER LEVEL TROF AND
DIVERGENT SIDE OF RIGHT ENTRANCE REGION OF SUBTROPICAL JET STREAK
AND APPROACHING SHEARLINE EXPECT ANOTHER ROUND OF CLOUDS AND
SHOWERS MON-TUE WITH DRYING COMMENCING ON WED AS AREA BECOMES
UNDER UPPER LEVEL CONFLUENCE AND CONVERGENT SIDE OF JET STREAK AS
TROUGH PULLS AWAY FROM THE REGION. SHOWERS THOUGH WILL BE ON THE
LIGHT SIDE AS PWAT REMAIN LOW BUT EXPECT A COUPLE OF VERY COOL AND
CLOUDY DAYS WITH THINGS IMPROVING WED. NORTHEAST QUADRANT OF PR
WILL BE THE MOST FAVORED LOCATION FOR SHOWERS UNDER A COOL
NORTHEAST UPSLOPE FLOW. WINDS WILL ALSO BE ON THE INCREASE TUE AS
PRES GRADIENT TIGHTENS AS STRONG HIGH PRES BUILDS ACROSS THE WRN
ATLC. WHILE MODELS SHOW PWAT INCREASING THU AND FRI WITH REMNANTS
OF A WANING FRONT AREA WILL BECOME INCREASINGLY UNDER UPPER LEVEL
CONFLUENCE SO BELIEVE CLOUDS AND MOISTURE ASSOCIATED WITH THIS
BDRY ARE BEING OVERDONE BY MODELS.
EXTREMELY DRY AIR IS NOW BEING ADVERTISED BY GFS AND ECMWF MODELS
FOR NEXT WEEKEND WITH PWAT FCST TO DROP BELOW 0.75 INCHES OR WELL
BELOW TWO STANDARD DEVIATIONS BELOW NORMAL.
&&
.AVIATION...VFR TONIGHT BUT CIGS BECOME BKN-OVC040 MON WITH SCT SHOWERS.
&&
.MARINE...NORTH SWELLS HAVE PEAKED AND WILL BE SUBSIDING LATE
TONIGHT. BREAKERS OF 10 TO 14 FT CAN STILL BE EXPECTED THROUGH
THIS EVENING. AFTER SWELLS SUBSIDE WINDS INCREASE TUE RAISING
SEAS TO 7 FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 83 73 83 / 20 20 40 40
STT 74 85 74 85 / 20 20 30 30
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
524 AM AST MON JAN 28 2013
.SYNOPSIS...AT UPPER LEVELS...A WEAK TROUGH PASSAGE...MAINLY NORTHEAST ON
TUESDAY NIGHT WILL BRING THE TAIL OF A JET ACROSS PUERTO RICO AND
THE U.S. VIRGIN ISLANDS. RIDGING WILL THEN APPROACH THE AREA
DURING THE REST OF THE WEEK AND PASS TO THE EAST OVER THE WEEKEND.
A STRONG UPPER LEVEL TROUGH WILL PASS TO THE NORTH ON
MONDAY...BRINGING ANOTHER JET OF AROUND 70 KNOTS.
AT MID LEVELS...HIGH PRESSURE REMAINS CLOSE TO THE AREA. A WEAK
EAST-WEST TROUGH PASSES THROUGH FROM THE NORTH ON WEDNESDAY.
AT LOWER LEVELS...A SHEARLINE WILL APPROACH PUERTO RICO AND THE
U.S. VIRGIN ISLANDS TODAY AND PASS THROUGH THE FORECAST AREA
TUESDAY NIGHT. MOISTURE FROM THIS DECAYING BOUNDARY WILL AFFECT
THE AREA THROUGH FRIDAY. DRIER WEATHER IS EXPECTED OVER THE WEEKEND.
&&
.DISCUSSION...WIDELY SCATTERED SHOWERS PASSED INTO PUERTO RICO
FROM THE ATLANTIC WATERS OVERNIGHT LEAVING OVER ONE QUARTER INCH
IN A FEW PLACES ACCORDING TO NATIONAL WEATHER SERVICE DOPPLER
RADAR. THE GFS SHOWS ADDITIONAL SHOWERS MOVING INTO THE AREA
DURING THE DAY TODAY. TRADE WIND FLOW WILL INCREASE AS HIGH
PRESSURE MOVES INTO THE ATLANTIC WATERS NORTH OF THE AREA AND
FORCES A SHEARLINE FROM THE NORTH OVER THE FORECAST AREA TUESDAY
NIGHT. SHOWERS WILL ACCOMPANY THE SHEARLINE AND ARE LIKELY TO
PENETRATE A LITTLE DEEPER INTO THE ISLAND UNDER THE STRONGER
WINDS. ON SATURDAY THE GFS IS CONSISTENT IN BRINGING IN DRIER
AIR...THE EUROPEAN MODEL IS EARLIER AND NOT AS DRY. IN THE
MEANTIME...HOWEVER...BANDS OF SHOWERS AND CLEARING WILL PASS
THROUGH WEDNESDAY THROUGH FRIDAY ASSOCIATED WITH THE SHEARLINE
THAT STALLS JUST SOUTH OF THE AREA ON THURSDAY AND THEN RETURNS.
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED TO CONTINUE ACROSS ALL TAF
SITES THROUGH AT LEAST 28/22Z. ONLY VCSH EXPECTED FROM TIME TO TIME
OVER TNCM...TKPK...TIST...AND TISX WITH BRIEF PERIODS OF MVFR
POSSIBLE. AREAS OF MOUNTAIN OBSCURATIONS WILL PERSIST OVER PUERTO
RICO TILL AT LEAST 28/20Z. EAST TO NORTHEAST WINDS WILL CONTINUE TO
PREVAIL BETWEEN 10 TO 20 KTS FROM THE SURFACE UP TO 15K
FEET...BECOMING WESTERLY AND STRONGER ABOVE WITH WINDS UP TO 70
KTS AT 40K FEET.
&&
.MARINE...SEAS AT THE OUTER BUOY 41043 HAVE SUBSIDED BELOW 6 FEET
WHILE SEAS AT THE INNER BUOY HAVE SUBSIDED BELOW 5 FEET. THEREFORE
HAVE CANCELED BOTH THE HIGH SURF ADVISORY AND THE SMALL CRAFT
ADVISORY IN EFFECT. SEAS GENERATED BY LOCAL WINDS WILL BE INCREASING
OVER THE AREA DUE TO THE ENTRY OF HIGH PRESSURE INTO THE WATERS TO
THE NORTH AND EXPECT 7-FOOT SEAS AGAIN IN THE OUTER ATLANTIC
WATERS ON TUESDAY. SEAS WILL REMAIN ELEVATED FOR THE REST OF THE
WEEK THERE AND SPREAD FARTHER SOUTH AFTER TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 72 81 73 / 40 30 40 50
STT 85 72 84 74 / 20 30 40 40
NATIONAL WEATHER SERVICE SAN JUAN PR
320 PM AST MON JAN 28 2013
.SYNOPSIS...A WEAK UPPER TROUGH NORTHEAST OF THE AREA WILL PUSH
THE TAIL OF A JET ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS
DURING THE NEXT 24 HOURS. MID TO UPPER RIDGE WILL ESTABLISH BY
MIDWEEK AND CONTINUES THROUGH THE WEEKEND. AT LOWER LEVELS...A
SHEARLINE AND A WEAK FRONTAL BOUNDARY WILL REMAIN CLOSE TO THE
FORECAST AREA...BRINGING FRAGMENTS OF CLOUDS AND SHOWERS FROM TIME
TO TIME. DRIER WEATHER IS EXPECTED OVER THE FRIDAY AND SATURDAY.
&&
.DISCUSSION...SATELLITE AND RADAR IMAGERY SHOW PATCHES OF LOW
CLOUDS AND SHOWERS EMBEDDED IN THE TRADES...AFFECTING MOST OF
THE ISLANDS AS WELL AS THE REGIONAL WATERS. MOST OF THIS SHOWER
ACTIVITY TODAY IS ASSOCIATED WITH THE SHEARLINE JUST NORTH OF
PUERTO RICO. LITTLE CHANGE IN THE WEATHER CONDITIONS IS FORECAST
FOR THE NEXT FEW DAYS AS A WEAK FRONTAL BOUNDARY WILL MOVE OVER
THE ISLANDS LATE TUESDAY AND WEDNESDAY. AS A RESULT...CONTINUE TO
EXPECT ADDITIONAL BANDS/PATCHES OF SHOWERS AND CLOUDS MOVING ACROSS
THE LOCAL AREA THROUGH AT LEAST LATE THURSDAY. RAINFALL AMOUNTS
WILL TEND TO BE LIGHT...AFFECTING MAINLY THE VIRGIN ISLANDS AND
NORTH AND EAST PORTIONS OF PUERTO RICO. DRY AND STABLE AIR MASS
IS THEN FORECAST FOR FRIDAY AND SATURDAY.
&&
.AVIATION...CLEARING TONIGHT BUT SKIES BECOMING CLOUDY AGAIN
TOMORROW WITH CIGS OVC040 WITH SCATTERED SHOWERS. SFC WINDS LIKELY
TO STAY UP AT JBQ/JSJ AND IST AT LEAST 10KT AS PRES GRADIENT
TIGHTENS. JPS/JMZ AND ISX ARE MORE SHELTERED AND ARE MORE LIKELY TO
SEE WINDS DROP OFF AFTER SUNSET.
&&
.MARINE...WINDS WILL INCREASE AS A SURFACE HIGH PRESSURE MOVES
JUST NORTH OF PUERTO RICO OVER THE NEXT COUPLE OF DAYS...RESULTING
IN SEAS BUILDING TO 7 FEET BY TUESDAY MORNING. AS A RESULT...SCA
IS NOW IN EFFECT FOR AMZ710. SCA CONDITIONS WILL SPREAD OVER THE
REMAINDER OF THE MARINE ZONES THROUGH THE WEEK WITH THE PEAK IN
WINDS AND SEAS EXPECTED THU.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 72 81 73 83 / 30 40 40 40
STT 72 84 74 85 / 30 40 30 30
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
545 AM AST TUE JAN 29 2013
.SYNOPSIS...SHEARLINE NORTH OF THE LOCAL ISLANDS AND A FRONTAL
BOUNDARY JUST BEHIND IT WILL CONTINUE TO SLOWLY MOVE SOUTH. WHILE
THE SHEARLINE MAY MOVE OVER THE ISLANDS...THE FRONTAL BOUNDARY IS
EXPECTED TO REMAIN TO OUR NORTH...BRINGING AN INCREASE IN
CLOUDINESS AND SCATTERED TO NUMEROUS PASSING SHOWERS. WEAK UPPER
TROUGH WILL SLOWLY MOVE EAST WHILE A MID TO UPPER RIDGE MOVES INTO
THE AREA AND ESTABLISHES BY MIDWEEK THROUGH THE WEEKEND.
&&
.DISCUSSION...CLOUDS AND SHOWERS STARTED TO MOVE IN OVERNIGHT FROM
THE NORTH DUE TO THE APPROACHING SHEARLINE. THIS ACTIVITY IS
EXPECTED TO CONTINUE TODAY...BRINGING SCATTERED TO NUMEROUS
SHOWERS ACROSS THE LOCAL ISLANDS WITH VARIABLY TO MOSTLY CLOUDY
SKIES. THE FRONTAL BOUNDARY RIGHT BEHIND THE SHEARLINE IS
EXPECTED TO APPROACH THE LOCAL ISLANDS TODAY AND WEDNESDAY...WHICH
SHOULD CONTINUE TO BRING CLOUDS AND SHOWERS ACROSS THE AREA
THROUGH THURSDAY. THE RAINFALL EXPECTED FOR THE NEXT FEW DAYS WILL
LIKELY BE LIGHT TO MODERATE.
STARTING ON FRIDAY AND THROUGH THE WEEKEND...A DRIER AIRMASS IS EXPECTED
TO MOVE IN...BRINGING MORE FAVORABLE WEATHER CONDITIONS WITH ONLY
ISOLATED PASSING SHOWERS.
&&
.AVIATION...A SHEAR LINE 300 MILES NNE OF TJSJ IS MOVING AT ABOUT 18
KNOTS AND INTO THE FCST AREA AS OF 29/05Z. THIS WILL BRING INCRG
CLDS AND SHRA TO SMALLER ISLANDS AND THE WINDWARD SIDE OF PR NORTH
OF THE CORDILLERA CENTRAL WITH ATTENDANT AREAS OF MVFR AND MOUNTAIN
OBSCURATIONS BEGINNING ARND 29/07Z WITH THE PRECEDING CLD COVER AND
ENDING BTWN 30/06-09Z BY CURRENT ESTIMATES AFT SHEARLINE PASSES. MID
LYRS WILL BCM BKN FIRST FOLLOWED BY AREAS OF LOWER CLDS AS SHEARLINE
PASSES. LLVL WNDS ENE 5-20 KTS INCRG TO 10 TO 25 KTS BY 29/15Z WITH
LCLY HIR GUSTS.
&&
.MARINE...SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE OFFSHORE
ATLANTIC WATERS. LOCAL BUOY DATA SUGGESTS THAT THE OFFSHORE
ATLANTIC WATERS WILL START TO SEE AN INCREASE IN WAVE HEIGHTS
TODAY...CAUSING SEAS UP TO 7 FEET. WHILE THE SAN JUAN BUOY IS
REPORTING SEAS OF ABOUT 5 FEET...BUOY 41044 TO THE NORTHEAST OF
THE LOCAL ISLANDS HAS BEEN REPORTING SEAS AROUND 7 FEET FOR THE
PAST 12 HOURS. THEREFORE...THE SMALL CRAFT ADVISORY FOR THE
OFFSHORE ATLANTIC WATERS REMAINS IN EFFECT DUE TO AN EXPECTED
INCREASE IN WAVE HEIGHTS TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 83 73 / 60 50 40 30
STT 84 73 84 75 / 50 30 30 30
NATIONAL WEATHER SERVICE SAN JUAN PR
320 PM AST TUE JAN 29 2013
.SYNOPSIS...MID TO UPPER RIDGE OVER EASTERN U.S. WILL CONTINUE TO
PROPAGATE EASTWARD AND IS FORECAST TO ESTABLISH OVER THE REGION BY
THURSDAY. SURFACE HIGH PRESSURE NORTH OF PUERTO RICO WILL CONTINUE
TO INDUCE A LONG FETCH EAST-NORTHEAST FLOW ACROSS THE NORTHEAST
CARIBBEAN...BRINGING BREEZY AND SHOWERY WEATHER ACROSS THE FORECAST
AREA THROUGH EARLY THURSDAY. DRIER AND MORE STABLE PATTERN IS EXPECTED
FRIDAY AND SATURDAY.
&&
.DISCUSSION...THE CURRENT RADAR AND VISIBLE SATELLITE IMAGERY
SHOW DISORGANIZED CLOUDS AND SHOWERS STRETCHING ACROSS MUCH OF
THE FORECAST AREA THIS AFTERNOON. THE CLOUDS AND SHOWERS ARE A
RESULT OF REMNANT MOISTURE FROM AN OLD FRONTAL BOUNDARY LOCATED
ALONG 20N. SOME OF THESE SHOWERS HAVE BEEN ENHANCED BY THE SUBTROPICAL
JET NORTHEAST OF THE ISLANDS...RESULTING IN MODERATE TO LOCALLY
HEAVY RAINFALL IN ISOLATED AREAS OF PR. THIS COOL ADVECTIVE PATTERN
IS FORECAST TO REMAIN THROUGH LATE WEDNESDAY...WITH A GRADUAL
DECREASE IN SHOWER ACTIVITY ON THURSDAY. GFS AND NCEP WRF SUGGEST
THE MOST ACTIVE PERIOD TONIGHT AND EARLY WEDNESDAY...WITH A GRADUAL
IMPROVEMENT OF THURSDAY. FOR FRIDAY AND SATURDAY...A RELATIVELY FAIR
WEATHER IS EXPECTED ACROSS THE LOCAL ISLANDS AS MID TO UPPER RIDGE
PROMOTES AN STABLE AIR MASS AND A SUBSIDENCE PATTERN ACROSS THE REGION.
&&
.AVIATION...MOSTLY VFR CONDS FOR THE REST OF THE PERIOD. HOWEVER
INTERVALS OF ISOLD-SCT PASSING LOW LEVEL CLD LAYERS MAINLY BTW
FL020-FL090 WITH FEW-SCT PASSING SHRA WILL CONTINUE TO AFFECT THE
LOCAL FLYING AREA AT LEAST TIL 30/00Z.
&&
.MARINE...LOCAL BUOY OBSERVATIONS EARLY THIS AFTERNOON SUGGEST SEAS
BETWEEN 4 TO 6 FEET AT 6 TO 8 SECS AFFECTING THE LOCAL WATERS AND PASSAGES.
ALL OF THESE WAVES ARE MAINLY WIND WAVES GENERATED LOCALLY ACROSS THE
REGIONAL WATERS NORTH OF PUERTO RICO. BUOY 41043 NE OF PR MEASURED UP
TO 8 FEET AT 2 PM AST. THEREFORE EXPECT MOSTLY WIND DRIVEN HAZARDOUS
SEA CONDITIONS. SMALL CRAFT ADVISORY REMAIN IN EFFECT FOR THE OFFSHORE
ATLANTIC AND SMALL CRAFT SHOULD EXERCISE CAUTION ELSEWHERE DUE TO
CHOPPY SEA CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 83 73 82 / 50 40 30 50
STT 73 84 75 84 / 30 30 30 60
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
556 AM AST WED JAN 30 2013
.SYNOPSIS...MID TO UPPER RIDGE OVER EASTERN U.S. WILL CONTINUE TO
MOVE EASTWARD AND WILL ESTABLISH OVER THE LOCAL AREA REGION BY
THURSDAY. SURFACE HIGH PRESSURE NORTH OF PUERTO RICO WILL CONTINUE
TO INDUCE A LONG FETCH EAST-NORTHEAST FLOW ACROSS THE NORTHEAST
CARIBBEAN...BRINGING BREEZY AND SHOWERY WEATHER ACROSS THE FORECAST
AREA UNTIL THURSDAY. DRIER AND MORE STABLE WEATHER IS EXPECTED
FRIDAY AND SATURDAY.
&&
.DISCUSSION...SCATTERED SHOWERS ACROSS THE AREA ARE EXPECTED TO
CONTINUE THROUGH THE DAY UNDER AN EAST NORTHEAST TRADE WIND FLOW.
THIS IS DUE TO THE SURFACE HIGH PRESSURE TO THE NORTH OF THE
ISLANDS COMBINED WITH THE LINGERING MOISTURE OF AN OLD FRONTAL
BOUNDARY NORTH OF THE LOCAL ISLANDS. SO SHOWERS ACROSS THE
WATERS...NORTH AND EASTERN PUERTO RICO AND THE U.S. VIRGIN ISLANDS
EXPECTED IN THE MORNING...THEN IN THE AFTERNOON SHOWERS POSSIBLE
ACROSS NORTHEASTERN AND SOUTHWESTERN PUERTO RICO AS WELL. FOR
THURSDAY...AN AREA OF EVEN HIGHER MOISTURE IS EXPECTED TO MOVE IN
FROM THE EAST NORTHEAST...BRINGING SCATTERED TO NUMEROUS SHOWERS
ACROSS THE AREA...ESPECIALLY FROM EASTERN PUERTO RICO TO THE U.S.
VIRGIN ISLANDS. HOWEVER STARTING ON FRIDAY DURING THE DAY AND INTO
THE WEEKEND...MODEL GUIDANCE SUGGESTS MUCH DRIER AIR MOVING INTO
THE AREA...WHICH SHOULD LIMIT SHOWER ACTIVITY TO ISOLATED LIGHT
SHOWERS.
&&
.AVIATION...MOSTLY VFR CONDS FOR THE NEXT 24 HOURS. HOWEVER INTERVALS
OF ISOLD-SCT PASSING LOW LEVEL CLD LAYERS MAINLY BTW FL020-FL090
WITH FEW-SCT PASSING SHRA WILL CONTINUE TO AFFECT THE LOCAL FLYING
AREA. INCREASE IN CLOUDS THROUGH THE DAY WILL CAUSE MOUNTAIN
OBSCURATIONS AS THE DAY GOES ON. WIND IS EXPECTED TO REMAIN FROM
THE EAST NORTHEAST AT 5 TO 15 KNOTS WITH SEA BREEZE VARIATIONS.
&&
.MARINE...SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE OFFSHORE
ATLANTIC WATERS. LATEST NEARSHORE BUOY DATA SUGGESTS THAT THE SEAS
ARE CHOPPY AT 4 TO 5 FEET WITH WINDS AROUND 15 KNOTS. IN
ADDITION...30/00Z SWAN MODEL RUN SUGGESTED THAT THE INCREASE IN SEAS TO
7 FEET FOR THE ANEGADA PASSAGE AND AROUND THE USVI WILL BE AFTER
31/06Z. FOR THAT REASON...FORECAST SEA HEIGHTS WERE KEPT UP TO 6
FEET ACROSS THE NEARSHORE WATERS UNTIL THURSDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 72 82 73 / 30 30 50 50
STT 84 74 84 73 / 30 30 60 30
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
335 PM AST WED JAN 30 2013
.SYNOPSIS...RIDGE ALOFT WILL RELOCATE OVER THE REGION FRIDAY AND
CONTINUE THROUGH THE WEEKEND. SURFACE HIGH PRESSURE NORTH-NORTHEAST
OF PUERTO RICO WILL CONTINUE TO INDUCE A LONG FETCH EAST-NORTHEAST
FLOW ACROSS THE NORTHEAST CARIBBEAN...BRINGING BREEZY AND SHOWERY
WEATHER ACROSS THE FORECAST AREA UNTIL THURSDAY. FAIR WEATHER
CONDITIONS IS EXPECTED FRIDAY AND SATURDAY.
&&
.DISCUSSION...SATELLITE IMAGERY AND LATEST SFC ANALYSIS SHOW
FRAGMENTS OF MOISTURE ASSOCIATED WITH AN OLD FRONTAL BOUNDARY JUST
NORTH AND EAST OF THE FORECAST AREA. SATELLITE BLENDED PWAT ANALYSIS
INDICATES AN ELONGATED AREA OF MOISTURE ORIENTED MAINLY WEST TO EAST
ALONG 20 NORTH. SURFACE HIGH PRESSURE NORTH OF THE AREA WILL CONTINUE
TO PUSH FRAGMENTS/PATCHES OF MOISTURE ACROSS PUERTO RICO AND THE
VIRGIN ISLANDS DURING THE NEXT 24-36 HOURS. AS A RESULT...EXPECT
SCATTERED TO NUMEROUS SHOWERS AND LOCALLY BREEZY CONDITIONS AFFECTING
PORTIONS OF THE LOCAL ISLANDS FROM TIME TO TIME THROUGH LATE THURSDAY.
FOR FRIDAY AND THE UPCOMING WEEKEND...SYNOPTIC MODELS SUGGEST THAT
THE MID/UPPER RIDGE WILL FAVOR THE EROSION OF THE AVAILABLE MOISTURE
ACROSS THE NORTHEAST CARIBBEAN BY MIDDAY FRIDAY. GFS FORECAST SOUNDINGS
SUGGEST PWAT MINIMA OF 0.85 INCHES AND A STRONG SUBSIDENCE CAP AROUND
800 MB BY SATURDAY MORNING. MODEL GUIDANCE SUGGESTS RELATIVELY FAIR
WEATHER CONTINUING EARLY NEXT WEEK.
&&
.AVIATION...LARGE AREA OF SHRA ON SATELLITE N OF NORTHERN ANTILLES
WILL PASS OVER PR/USVI TONIGHT AND ESPECIALLY THU...AND THE MOISTURE
WILL BE RELATIVELY DEEP FOR THE SEASON. SOME TEMPO INCLUDED IN 18Z
TAFS BUT MORE MAY BE NEEDED LATER WHEN TIMING IS BETTER KNOWN. SOME
MTN OBSCG LIKELY LATE TONIGHT/THU. LLVL WIND TO FL150 ENE-NE 15-25
KT BCMG E ON THU.
&&
.MARINE...LATEST COASTAL OBSERVATIONS SHOW THAT THE WIND HAVE BEEN
INCREASED ACROSS THE REGIONAL WATERS IN THE LAST COUPLE OF HOURS.
LOCAL BUOYS MEASURED WINDS INCREASING FROM AROUND 16-18 KTS THIS
MORNING TO 18-22 KTS THIS AFTERNOON AND SEAS BUILDING FROM 5 TO 7
FEET. SMALL CRAFT ADVISORIES ARE IN EFFECT MOST OF THE LOCAL
WATERS...EXCLUDING THE NEARSHORE CARIBBEAN WATERS AND MONA PASSAGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 84 73 84 / 30 50 50 10
STT 74 84 73 84 / 30 60 30 0
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
954 PM AST WED JAN 30 2013
.UPDATE...LATEST SATELLITE IMAGES AND RADAR OBSERVATIONS LATE THIS
EVENING DEPICTED SCATTERED TO NUMEROUS SHOWERS MAINLY ACROSS THE
ATLANTIC AND CARIBBEAN COASTAL WATERS WITH FEW OF THEM AFFECTING
FROM TIME TO TIME THE NORTHERN AND EASTERN SECTIONS OF PUERTO RICO.
THESE SHOWERS WERE THE RESULT OF THE REMNANTS OF AN OLD FRONTAL
BOUNDARY NORTH OF THE LOCAL ISLANDS. THIS ACTIVITY WILL CONTINUE TO
BE ENHANCED BY A SEGMENT OF THE SUBTROPICAL JET JUST NORTH NORTHEAST
OF THE REGION. FRAGMENTS OF LOW LEVEL CLOUDINESS WITH EMBEDDED
SHOWERS ARE EXPECTED TO MOVE WEST SOUTHWESTWARD IN THE CIRCULATION
OF A SURFACE HIGH PRESSURE JUST NORTH OF THE LOCAL ISLANDS. AS A
RESULT...EXPECT SCATTERED TO NUMEROUS SHOWERS AND LOCALLY BREEZY
CONDITIONS AFFECTING PORTIONS OF THE LOCAL ISLANDS FROM TIME TO TIME
THROUGH LATE THURSDAY. HOWEVER...DUE TO THE RAPID MOVEMENT OF THE
SHOWERS THE TOTAL RAINFALL AMOUNTS WERE GENERALLY MINIMAL. A
DECREASE IN SHOWER ACTIVITY IS EXPECTED BY FRIDAY WITH A GENERAL DRY
WEATHER PATTERN EXPECTED TO RESUME AGAIN OVER THE FA BY THE UPCOMING
WEEKEND AS A MID TO UPPER LEVEL RIDGE RETURN TO THE REGION.
&&
.AVIATION...
.DISCUSSION...LARGE AREA OF SHRA ON SATELLITE N OF NORTHERN ANTILLES
AND APCHG NE COAST OF PR WILL PASS OVER PR/USVI TONIGHT AND
ESPECIALLY THU...AND THE MOISTURE WILL BE RELATIVELY DEEP FOR THE
SEASON. EXPECT INTERMITTANT SHRA OVER ALL AREAS NOW THRU BYD 01/02Z
EXCEPT S OF THE CORDILLERA CENTRAL IN PR WHERE OCNL SHRA WILL
OCCUR...MAINLY BTWN 31/15-24Z. LLVL WIND TO FL150 ENE-NE 15-25 KT
BCMG E ON THU.
&&
.MARINE...LATEST COASTAL AND BUOYS OBSERVATIONS SHOW THAT THE WIND
HAVE BEEN INCREASED ACROSS THE REGIONAL WATERS THIS EVENING.
LOCAL BUOYS MEASURED WINDS INCREASING FROM AROUND 16-18 KTS THIS
AFTERNOON TO 18-22 KTS THIS EVENING AND SEAS BUILDING FROM 5 TO 7
FEET. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR MOST OF THE LOCAL
WATERS...EXCLUDING THE NEARSHORE CARIBBEAN WATERS AND MONA
PASSAGE.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
613 AM AST THU JAN 31 2013
.SYNOPSIS...MODEL GUIDANCE CONTINUES TO SUGGEST THAT THE UPPER
RIDGE WILL MOVE AND ESTABLISH OVER THE REGION ON FRIDAY AND
CONTINUE THROUGH THE WEEKEND. SURFACE HIGH PRESSURE NORTH NORTHEAST
OF PUERTO RICO WILL CONTINUE TO INDUCE AN EAST NORTHEASTERLY FLOW
ACROSS THE NORTHEAST CARIBBEAN...BRINGING BREEZY AND SHOWERY
WEATHER ACROSS THE LOCAL TODAY AND TONIGHT. A SIGNIFICANT
IMPROVEMENT IN WEATHER CONDITIONS IS EXPECTED FOR THE WEEKEND.
&&
.DISCUSSION...SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED TODAY
ACROSS THE LOCAL AREA. IN THE MORNING HOURS...THE NUMEROUS SHOWER
ACTIVITY IS EXPECTED TO CONTINUE ACROSS THE WATERS AND THE USVI. IN
THE LATE MORNING TO THE AFTERNOON HOURS...THE SHOWER ACTIVITY MAY
START TO AFFECT LAND AREAS IN PUERTO RICO...ESPECIALLY EASTERN
PUERTO RICO. THERE IS A BIT OF DISAGREEMENT IN THE MODELS AS THE
NAM MODEL SUGGESTS THAT THERE WILL BE NUMEROUS SHOWERS ACROSS
PUERTO RICO INCLUDING WESTERN PUERTO RICO IN THE AFTERNOON WHILE
THE GFS MODEL KEPT WESTERN PUERTO RICO FAIRLY DRY. GIVEN THE SPEED
IN WHICH THESE SHOWERS ARE MOVING WHICH IS AROUND 15 KNOTS...THE
FORECAST CALLS FOR NUMEROUS SHOWERS IN THE AFTERNOON ACROSS
PUERTO RICO INCLUDING WESTERN PUERTO RICO AS THE SHOWERS QUICKLY
PASS BY.
SIGNIFICANT REDUCTION IN SHOWER ACTIVITY IS EXPECTED STARTING ON
FRIDAY DURING THE DAY AND THROUGH THE WEEKEND AS A DRIER AND MORE
STABLE AIRMASS MOVES IN AND THE UPPER RIDGE MOVES OVER THE AREA.
&&
.AVIATION...SHRA ACTIVITY IS EXPECTED ACROSS THE LOCAL TERMINALS
TODAY. THIS WILL CAUSE MOMENTS OF MVFR CONDITIONS AS THE SHRA
ACTIVITY PASSES BY. AN INCREASE IN CLOUDS IN THE LATE MORNING AND
AFTERNOON WILL CAUSE MOUNTAIN OBSCURATIONS ACROSS THE HIGHER
ELEVATIONS OF PUERTO RICO. WIND WILL BE MAINLY FROM THE EAST
NORTHEAST AT AROUND 10 TO 15 KNOTS WITH HIGHER GUSTS AS WELL AS
SEA BREEZE VARIATIONS.
&&
.MARINE...SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE NORTHERN
AND EASTERN WATERS DUE TO WIND GENERATES WAVES. WIND IS EXPECTED
TO REACH 22 KNOTS AND SEAS MAY BUILD AS MUCH AS 8 FEET ACROSS THE
OFFSHORE ATLANTIC WATERS. THE REST OF THE WATERS NOT IN THE
ADVISORY HAVE A PRECAUTIONARY STATEMENT DUE TO SEAS OF UP TO 6
FEET OR WINDS OF AT LEAST 18 KNOTS WITH THE EXCEPTION OF THE
NEARSHORE WATERS OF SOUTHWEST PUERTO RICO.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 82 72 / 70 70 40 20
STT 84 73 83 74 / 60 60 10 20
NATIONAL WEATHER SERVICE SAN JUAN PR
306 PM AST THU JAN 31 2013
.SYNOPSIS...MID TO UPPER LEVEL RIDGE PATTERN WILL CONTINUE TO HOLD
ACROSS THE NORTHEAST CARIBBEAN THROUGH THE MUCH OF THE UPCOMING
WEEKEND. HOWEVER IT WILL BEGIN TO ERODE AND SHIFT EASTWARD BY LATE
SUNDAY THROUGH MONDAY ...IN RESPONSE TO AN AMPLIFYING LONG WAVE
TROUGH WHICH WILL MOVE ACROSS THE EASTERN SEABOARD OF THE UNITED
STATES AND ENTER THE WESTERN ATLANTIC BY EARLY NEXT WEEK. AT LOW
LEVELS...STRONG HIGH PRESSURE RIDGE ACROSS THE CENTRAL ATLANTIC
AND NORTH OF THE REGION WILL MAINTAIN MODERATE TO FAIRLY STRONG
EASTERLY TRADE WINDS ACROSS THE LOCAL ISLANDS AND SURROUNDING WATERS
THROUGH THE MUCH OF THE WEEKEND. AS A RESULT EXPECT OCCASIONAL PATCHES
OF SHALLOW TRADE WIND MOISTURE TO CONTINUE TO WILL QUICKLY SURGE
ACROSS THE REGION FROM TIME TO TIME.
&&
.DISCUSSION...LATEST SATELLITE IMAGERY CONTINUE TO SHOW CLUSTERS OF
SHALLOW LOW LEVEL CLOUDS WITH AREAS OF EMBEDDED SHOWERS QUICKLY
STREAMING ACROSS THE REGION DURING THE AFTERNOON. THE PREVAILING
MODERATE EASTERLY TRADES WILL HOWEVER QUICKLY PUSH THE SHOWER ACTIVITY
ACROSS THE ISLANDS AND SURROUNDING WATERS LEAVING MINIMAL RAINFALL
ACCUMULATIONS. FOR THE REST OF THE EVENING AND EARLY MORNING HOURS...
EXPECT CONTINUED VARIABLY CLOUDY SKIES...WITH PERIODS OF PASSING
SHOWERS AFFECTING THE LOCAL WATERS AND BRUSHING PARTS OF THE ISLANDS...
AS ANOTHER SURGE OF MOISTURE WILL MOVE ACROSS THE AREA. LATEST
SATELLITE DERIVED PWAT ANALYSIS SUGGESTED VALUES WERE AROUND 1.30
INCHES ACROSS THE REGION TODAY. HOWEVER LATEST MODEL GUIDANCE
WERE ALL CONSISTENT IN SUGGESTING SIGNIFICANT DECREASE IN PWAT
VALUES OVER THE NEXT SEVERAL DAYS. THEREFORE STILL LOOKING FOR A
DRYER AIR MASS BEGINNING ON FRIDAY AND CONTINUE THROUGH THE WEEKEND.
AS A RESULT MOSTLY FAIR WEATHER SKIES CAN BE EXPECTED FOR THE WEEKEND.
&&
.AVIATION...ISOLD-SCT SHRA WILL CONTINUE TO MOVE ACROSS THE
FLYING AREA THROUGH AT LEAST 01/16Z. AS A RESULT...BRIEF MVFR
CONDITIONS AND MOUNTAIN OBSCURATIONS ARE POSSIBLE IN PASSING SHRA.
LLVL WNDS WILL REMAIN MAINLY FM THE E AT 15-20 KTS WITH LOCALLY
HIGHER SFC WND GUSTS NEAR SHRA.
&&
.MARINE...LOCAL BUOYS AND SHIP REPORTS INDICATED WINDS RANGING
BETWEEN 17 AND 22 KTS...AND SEAS BETWEEN 5 AND 8 FEET DURING THE
AFTERNOON HOURS. AS A RESULT...SMALL CRAFT ADVISORIES REMAINS IN
EFFECT FOR MOST OF THE LOCAL WATERS...EXCLUDING THE NEAR SHORE WATERS
OF SOUTHERN AND WESTERN PUERTO RICO. THE SMALL CRAFT ADVISORY FOR
THE NEAR SHORE WATERS OF NORTHWESTERN PUERTO RICO WAS CANCELLED
EARLIER TODAY AS WINDS AND SEAS AT THE BUOY 41115 WERE BELOW THE
SCA CRITERIA. SMALL CRAFT OPERATORS SHOULD HOWEVER EXERCISE
CAUTION ACROSS THESE AREAS DUE TO CONTINUED CHOPPY CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 74 83 71 82 / 50 40 30 20
STT 74 83 72 84 / 50 20 30 20
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1003 PM AST THU JAN 31 2013
.SYNOPSIS...UPPER LEVEL RIDGE WILL BUILD OVERHEAD FRI AND HOLD
THROUGH THE WEEKEND. RIDGE COLLAPSES EARLY NEXT WEEK AS ANOMALOUS
DEEP TROF ACROSS ERN NOAM ENTERS THE WRN ATLC.
&&
.DISCUSSION...SCT SHOWERS STILL POSSIBLE OVERNIGHT MAINLY ACROSS
THE ATLC COASTAL WATERS...ERN PR AND USVI WITH REMNANT MOISTURE
ASSOCIATED TO AN OLD FRONTAL BDRY. BUILDING UPPER LEVEL RIDGE FRI WILL
RESULT IN SHARP DRYING TOMORROW FROM EAST TO WEST. BELIEVE MODELS
ARE OVERDOING PRECIP CHANCES LIKE THEY DID TODAY SO EXPECT MAINLY
SCT-BKN CLOUDS WITH ONLY SLIM CHANCES OF SHOWERS. VERY DRY AIR
MOVES INTO THE AREA FRI NIGHT THAT HOLDS INTO EARLY NEXT WEEK.
THIS IS AN EXCEPTIONALLY DRY AIR MASS WITH PWAT AOB TWO STANDARD
DEVIATIONS BELOW NORMAL. GUIDANCE ALSO INDICATES VERY LOW VALUES
OF H850 THETAE...K INDICES AND 0-2KM RH SUGGESTING STRONG
DOWNWARD/SINKING MOTION THAT EVEN CLOUDS MIGHT HAVE A HARD TIME TRYING
TO DEVELOP. PRECIP CHANCES LOOK PRETTY MUCH NIL OVER THE WEEKEND.
NEXT BEST CHANCE OF PRECIP IS REALLY NEXT WED AS SUBSIDENCE INVERSION
WEAKENS...LAPSE RATES STEEPEN AND MOISTURE INCREASES WITH UPPER
TROUGH.
&&
.AVIATION...SCT SHRA WILL CONTINUE TO MOVE ACROSS THE LOCAL FLYING
AREA THROUGH AT LEAST 01/16Z. AS A RESULT...BRIEF MVFR CONDITIONS
AND MOUNTAIN OBSCURATIONS ARE POSSIBLE IN PASSING SHRA. LLVL WNDS
WILL REMAIN MAINLY FM THE EAST AT 15-20 KTS WITH LOCALLY HIGHER
GUSTS NEAR SHRA.
&&
.MARINE...WINDS WILL BEGIN TO DIMINISH FRI WITH SEAS IMPROVING
OVER THE WEEKEND. WINDS WILL REMAIN BELOW 15 KNOTS MUCH OF NEXT
WEEK WITH SEAS GENERALLY 3-5 FT.
&&
.FIRE WEATHER...BUILDING UPPER LEVEL RIDGE WILL RESULT IN RAPID
EROSION OF LOW LEVEL MOISTURE WITH MODELS INDICATING WATER VAPOR
CONTENT DROPPING TWO STANDARD DEVIATIONS BELOW NORMAL OVER THE
WEEKEND. THIS IN COMBINATION WITH EXTREMELY DRY FUELS WILL RESULT
IN HEIGHTENED FIRE WEATHER CONDITIONS. WINDS PEAKED TODAY AND WILL
BE DIMINISHING SOMEWHAT OVER THE WEEKEND. STABILITY IS FCST TO
INCREASE OVER THE WEEKEND WHICH SHOULD TEND TO SUPPRESS ANY FIRES BUT
THE LONG DURATION OF VERY LOW HUMIDITIES AND EXTREMELY DRY FUELS
AND HIGH FUEL LOAD RAISES A LOT OF FLAGS AND CONCERNS. DON`T
EXPECT HUMIDITIES TO RECOVER AT NIGHT DUE TO EXTREME DRYNESS.
&&
.CLIMATE...AT CHARLOTTE AMALIE JAN 2013 WILL END AS THE DRIEST ON
RECORD WITH ONLY 0.55 INCHES OF RAIN. THE PREVIOUS DRIEST JAN ON
RECORD WAS IN 2007 WITH 0.76 INCHES.
AT CHRISTIANSTED...JAN 2013 WILL END AS THE TENTH DRIEST ON RECORD
WITH 1.05 INCHES OF RAIN. THE DRIEST JAN WAS IN 2011 WITH 0.49
INCHES OF RAIN.
AT SJU LMM INTL ARPT...JAN 2013 WILL END AS THE TWELFTH DRIEST ON
RECORD WITH 1.78 INCHES OF RAIN. THE DRIEST JAN ON RECORD WAS IN
1978 WITH 0.31 INCHES.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 83 73 82 / 40 10 0 0
STT 74 83 74 84 / 40 10 0 10
NATIONAL WEATHER SERVICE SAN JUAN PR
243 PM AST TUE FEB 19 2013
.SYNOPSIS...SURFACE HIGH PRESSURE ACROSS THE WESTERN ATLANTIC WILL
CONTINUE TO DOMINATE THE LOCAL REGION THROUGH AT LEAST WEDNESDAY.
UPPER LEVEL RIDGE WILL HOLD THROUGH MOST OF THE WEEK.
&&
.DISCUSSION...PATCH OF LOW LEVEL MOISTURE MOVED ACROSS PUERTO
RICO TODAY AND THIS AFTERNOON...BRINGING WITH IT...CLOUDINESS WITH
SOME FAST MOVING PASSING SHOWERS ACROSS THE AREA. THE PATCH OF
MOISTURE WILL LEAVE THE LOCAL AREA TONIGHT. ONLY LIGHT PASSING
SHOWERS ARE POSSIBLE...BUT OVERALL...DRY CONDITIONS WILL PREVAIL
TONIGHT. A SURFACE HIGH PRESSURE SYSTEM CONTINUES TO DOMINATE THE
LOCAL REGION. THIS SURFACE HIGH PRESSURE WILL SHIFT EAST...AS A
DEEP LOW PRESSURE SYSTEM MOVES ACROSS THE WESTERN ATLANTIC BY THE
END OF THIS WEEK. LATER...FOR THE WEEKEND...ANOTHER HIGH PRESSURE
WILL BUILD NORTH OF THE AREA...MAINTAINING RELATIVELY DRY AND STABLE
ATMOSPHERIC CONDITIONS ACROSS THE REGION.
&&
.AVIATION...VFR CONDS ARE EXPECTED THROUGH THE FORECAST PERIOD.
HOWEVER...CLOUDS AND SCT SHRA WILL AFFECT PORTIONS PR THROUGH
19/20Z. AS A RESULT...BRIEF PERIODS OF MVFR CONDS AND MOUNTAIN
OBSCURATIONS ARE POSSIBLE NEAR THE SHRA. LLVL WINDS WILL RANGE BTWN
10-20 KTS WITH WIND GUSTS UP TO 25 KT...ESPECIALLY NEAR SHRA.
&&
.MARINE...ROUGH AND HAZARDOUS MARINE CONDITIONS WILL CONTINUE
ACROSS THE LOCAL WATERS DUE TO THE COMBINATION OF FRESH WINDS AND
A NW SWELL. LATEST BOUY OBSERVATION INDICATED A DOWNWARD TREND IN
SEAS...BUT FORECAST IS ANOTHER SET OF SWELLS WILL ARRIVE TONIGHT. AS A
RESULT...A HIGH SURF ADVISORY REMAINS IN EFFECT THROUGH WEDNESDAY
EVENING. ALSO...SMALL CRAFT ADVISORIES CONTINUE FOR MOST OF THE
WATERS THROUGH THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 71 83 73 82 / 50 50 30 30
STT 74 84 75 84 / 30 30 20 20
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1025 PM AST TUE FEB 19 2013
.UPDATE...NO MAJOR CHANGES TO PREVIOUS FORECAST. A GENERALLY
FAIR AND STABLE WEATHER PATTERN IS EXPECTED TO PREVAIL ACROSS
THE LOCAL ISLANDS FOR THE NEXT FEW DAYS. HOWEVER...WITH THE
PREVAILING EASTERLY FLOW...STILL EXPECT BRIEF PERIODS OF LIGHT
PASSING SHOWERS.
&&
.AVIATION...WINDS WILL REMAIN AROUND 10 KT NORTH COAST...USVI
AND LEEWARD ISLANDS TERMINALS BUT INCREASE AGAIN TOMORROW AFTER
SUNRISE TO 15G25KT THEN BECOME CALM AFTER SUNSET TOMORROW. CIGS
WILL REMAIN VFR WITH NO SIG WX.
&&
.MARINE...HAZARDOUS MARINE CONDITIONS WILL CONTINUE TO PREVAIL
ACROSS THE LOCAL WATERS DURING THE OVERNIGHT HOURS DUE TO NORTH
NORTHWEST SWELLS AND STRONG TRADE WINDS. A GRADUAL IMPROVEMENT
IS EXPECTED TOMORROW MORNING THROUGH THURSDAY AS TRADE WINDS
DIMINISH AND SWELLS SUBSIDE.
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