AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1208 AM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY APPROACH THE REGION INTO FRIDAY. PERIODS
OF SHOWERS AND THUNDERSTORMS WILL PRECEDE THE FRONT. THE RAIN WILL
BE HEAVY AT TIMES. COOLER AND SHOWERY CONDITIONS WILL PERSIST
INTO THE FIRST HALF OF THE MEMORIAL DAY WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LINE OF CONVECTION MOVING ACROSS N NYS...CROSSING OUR NORTHERN
MOST COUNTIES. THIS ACTIVITY IS HEALTHY...BUT NOT SEVERE. FURTHER
SOUTH AND AREA OF SHRA WILL MOVE ACROSS MHWK VLY CAPITAL DISTRICT.
MOST OF THE ACTIVITY CONTINUES TO WEAKEN. ITS IMPACTS IN GRIDS
WERE LARGELY ADDRESSED IN 10PM WED UPDATE.
IN THIS UPDATE TEMPS WERE ADJUSTED SLIGHTLY AND WINDS ARE 5 TO 10
KTS ABV FCST...AND ADJUSTMENTS WERE MADE. OTHERWISE A WARM HUMID SUMMER
LIKE NIGHT WITH -SHRA AND TSTMS NORTH.
PREVIOUS DISCUSSION...THE CONCERN FOR THE OVERNIGHT IS THE CONVECTION OVER
EASTERN GREAT LAKES AND ACROSS EASTERN PA AND CENTRAL NY AND THE
POTENTIAL FOR HEAVY RAINFALL WITH SOME PORTIONS OF THE FORECAST
SATURATED FROM HEAVY RAINS TUESDAY NIGHT AND WEDNESDAY AFTERNOON.
PRECIPITABLE WATER VALUES FROM ALBANY'S 00Z SOUNDING IS 1.51
INCHES AND BUFFALO'S 1.48 INCHES. THE HRRR-3KM 15 MINUTE COMPOSITE
REFLECTIVITY IS HANDLING THE CURRENT CONVECTION PLACEMENT AND
INTENSITY PRETTY WELL. HAVE USED THIS FOR POPS AND TIMING INTO THE
EARLY MORNING HOURS. THE CONVECTION IS EXPECTED TO WEAKEN AS IT
MOVES EAST MAINLY AFTER MIDNIGHT AND WE ARE SEEING SOME SIGNS OF
THIS. HAVE SHOWERS LIKELY WITH SCATTERED THUNDERSTORMS WITH HEAVY
RAINFALL AND GUSTY WINDS. THE STORM PREDICTION CENTER HAS MUCH OF
FORECAST AREA IN SLIGHT RISK...MAY MENTION OF STRONG STORMS IN OUR
HAZARDOUS WEATHER OUTLOOK.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
COLD FRONT SLOWLY APPROACHES THE REGION ON THURSDAY...NOT CLEARING
CWA UNTIL FRIDAY MORNING.
SLOWLY MOVING FRONT WILL PROVIDE ENVIRONMENT FOR BOUTS OF HEAVY
RAIN THROUGH THE PERIOD. PWATS REMAIN IN THE 1.5 INCH RANGE
THROUGH THURSDAY...ONLY SLOWLY DROPPING OFF INTO FRIDAY.
APPROACHING UPPER LEVEL JET TOMORROW BRINGS RIGHT REAR QUAD INTO
FORECAST AREA FOR THE AFTERNOON. SEE HYDRO SECTION FOR DISCUSSION
ON FLOOD RISK.
SEVERE POTENTIAL TOMORROW IS NOT CLEAR CUT NOW. MODEL CAPE LOOKS
TO BE IN THE 1000 J/KG RANGE WITH BULK SHEAR RESPECTABLE IN THE
30-40 KNOT RANGE. MID LEVEL LAPSE RATES ARE RELATIVELY WEAK AT
5.5C/KM. SPC HAS REGION IN SEE TEXT. FROM TODAY/S VANTAGE POINT
THAT LOOKS APPROPRIATE.
WITH COLD FRONT MOVING THROUGH ON FRIDAY...SOME DIMINISHING IN
PRECIP EXPECTED FOR PART OF FRIDAY. HOWEVER GFS AND ECMWF COMING
INTO AGREEMENT ON CUT OFF MIGRATING SLOWLY FROM DELMARVA INTO NEW
ENGLAND INTO THE HOLIDAY WEEKEND. THIS WILL KEEP THE THREAT OF
RAIN/SHOWERS IN THE FORECAST FOR FRIDAY. WITH CWA ON COOL SIDE OF
SURFACE LOW TRACK...INSTABILITY LOOKS NEAR NIL. SO NO MENTION OF
TSRA FOR FRIDAY.
MINS ON SATURDAY MORNING IN ADIRONDACKS ARE FORECAST IN MID 30S.
THIS WOULD MEAN THREAT OF FROST GIVEN BEGINNING OF THE GROWING
SEASON THERE. WILL DEPEND ON CLOUDS AND PRECIP.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
MODEL GUIDANCE HAS TRENDED TO A WET START TO THE HOLIDAY WEEKEND
ALONG WITH CHILLY TEMPERATURES DUE TO MORE CLOUD COVER.
THE MODEL GUIDANCE HAS COME INTO FAIRLY GOOD AGREEMENT THAT AN AREA
OF LOW PRESSURE WILL FORM ON THE COLD FRONT JUST OFF COAST NEAR CAPE
COD AS SHORT WAVES MOVE THROUGH THE LONGWAVE. AN UPPER LEVEL LOW IS
EXPECTED TO DEVELOP OVER THE MID ATLANTIC REGION FRIDAY NIGHT WITH
ADDITIONAL SHORT WAVES MAINTAINING THIS UPPER LOW WITH IT MOVING
GRADUALLY NORTHWARD UP THE COAST. THE LOW ALONG THE BOUNDARY WILL
SLOW THE FRONT'S EASTWARD PROGRESS AND THROW RAIN SHOWERS AND CLOUDS
BACK ACROSS NEW ENGLAND AND EASTERN NEW YORK STATE SATURDAY. THE
REGION WILL REMAIN UNDER CYCLONIC FLOW THROUGH THE WEEKEND WITH
UPPER RIDGING NOT EXPECTED TO BEGIN TO BUILD IN UNTIL TUESDAY. AT
THE SURFACE...HIGH PRESSURE SHOULD BEGIN TO BUILD IN MONDAY AND
ESPECIALLY TUESDAY. IT APPEARS THE HIGH SHOULD HOLD ON FOR WEDNESDAY.
AS FOR TEMPERATURES...CHILLY. TEMPERATURES ARE EXPECTED TO RUN 10 TO
15 DEGREES BELOW NORMAL SATURDAY AND AGAIN SUNDAY. BRISK AND GUSTY
NORTHWESTERLY WINDS WILL ONLY ADD TO THE CHILL. TEMPERATURES ARE
EXPECTED TO MODERATE TOWARD SEASONABLE LEVELS MONDAY WITH THE HELP
OF SUNSHINE BUT STILL BE BELOW NORMAL BY AROUND 5 DEGREES.
THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY...
GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK
VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND
EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON
MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY.
NIGHTTIME LOWS OVER THE WEEKEND ARE EXPECTED TO BE IN THE 40S WITH
30S ACROSS THE HIGHER TERRAIN. WITH THE EXPANSION OF THE GROWING
SEASON BY THIS TIME FROST ADVISORIES MIGHT BE NEEDED. CONDITIONS
WILL BE MORE FAVORABLE FOR FROST SUNDAY NIGHT/MONDAY MORNING AND
MONDAY NIGHT/TUESDAY MORNING.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
VARIABLE CONDITIONS OVERNIGHT. THUNDERSTORM THREAT WILL PREVAIL
FOR THE NEXT COUPLE OF HOURS...AS LINGERING DAYTIME INSTABILITY
CONTINUES TO FUEL THESE STORMS. HAVE INCLUDED TEMPO GROUPS AT
KGFL/KALB TO ACCOUNT FOR ANY REMNANT THUNDERSTORM ACTIVITY.
ELSEWHERE...THE THREAT FOR VCSH WILL REMAIN THROUGHOUT THE NIGHT
AS SHOWERS/THUNDERSTORMS APPROACH FROM THE WESTERN NY/MID-ATLANTIC
REGION. A COMBINATION OF SATURATED LOW-LEVELS AND RECENT RAINFALL
SHOULD ALLOW FOR MVFR CEILINGS/VISIBILITIES TO DEVELOP AT ALL TAF
SITES DURING THE OVERNIGHT HOURS. KGFL/KPOU MAY BRIEFLY DIP TO IFR
LEVELS TOWARDS DAYBREAK BUT CONFIDENCE REMAINS ON THE LOWER SIDE
AT THIS TIME.
THE THREAT FOR SHOWERS/THUNDERSTORMS WILL INCREASE DURING THE DAY
THURSDAY AS RENEWED DAYTIME HEATING COMMENCES...WITH EXPECTED
SCATTERED TO WIDESPREAD THUNDERSTORM COVERAGE BY THE EARLY AFTERNOON
HOURS. FLYING CONDITIONS THURSDAY WILL FLUCTUATE BETWEEN VFR/MVFR
WITH PERIODS OF IFR ASSOCIATED WITH SHOWER/THUNDERSTORM ACTIVITY.
HAVE INTRODUCED LLWS INTO THE TAFS THROUGH THE OVERNIGHT PERIOD AS A
LOW-LEVEL JET PASSES OVERHEAD WITH LIGHT SOUTHERLY SURFACE WINDS
GENERALLY LESS THAN 5 KNOTS. THESE SOUTHERLY WINDS WILL INCREASE
SLIGHTLY DURING THE DAY THURSDAY TO 5-10 KNOTS...WITH THE POTENTIAL
FOR HIGHER GUSTS ASSOCIATED WITH ANY THUNDERSTORMS.
OUTLOOK...
THU-THU NIGHT...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY.
FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM.
SAT-MON...VFR/MVFR. CHC -SHRA.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS INTO SATURDAY. PERIODS OF RAIN...MODERATE
TO HEAVY AT TIMES WILL CONTINUE INTO THE HOLIDAY WEEKEND.
RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND
THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THURSDAY AFTERNOON.
WINDS WILL GENERALLY BE SOUTH AT 5 TO 10 MPH.
&&
.HYDROLOGY...
ECMWF AND GFS VERY AGGRESSIVE IN BRINGING HEAVY RAINFALL INTO CWA
INTO THE MEMORIAL DAY WEEKEND. OPERATIONAL ECMWF AND GFS PRODUCE
5-7.5 INCHES OF RAIN IN CWA INTO SUNDAY. GEFS SHOW AVERAGE OF 2.25
INCHES THROUGH WEEKEND WITH 4 MEMBERS PUSHING IN EXCESS OF 3
INCHES. WHILE NOT QUITE READY TO ACCEPT TOTALS OF EURO AND
GFS...ENOUGH GUIDANCE AVAILABLE TO AT LEAST WARRANT POTENTIAL OF
HEAVY RAIN THREAT IN HWO. FIRST CHALLENGE FOR HEAVY RAIN WILL COME
TOMORROW WITH SLOWLY MOVING FRONT. EASTERN CWA AND CENTRAL CWA
HAVE SEEN HEAVIEST RAIN OVER THE LAST TWO DAYS AND WOULD APPEAR TO
BE THE REGION WHERE FLASH FLOOD THREAT IS AT HIGHEST.
WILL MONITOR CLOSELY FOR AT LEAST POTENTIAL OF FLASH FLOOD OR
FLOOD WATCH THURSDAY INTO WEEKEND.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...OKEEFE
NEAR TERM...IAA/OKEEFE/SNYDER
SHORT TERM...OKEEFE
LONG TERM...IAA
AVIATION...IRL
FIRE WEATHER...OKEEFE
HYDROLOGY...SNYDER
