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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
347 AM EDT FRI MAY 29 2015

.SYNOPSIS...
HIGH PRESSURE WILL SET UP OVER THE ATLANTIC THROUGH SATURDAY. A
COLD FRONT APPROACHES SATURDAY NIGHT AND MOVES THROUGH THE REGION
ON SUNDAY. THE FRONT WILL STALL JUST SOUTH OF THE AREA AS WEAK
WAVES OF LOW PRESSURE RIDE ALONG IT. HIGH PRESSURE THEN BUILDS IN
FROM THE NORTH LATE TUESDAY INTO WEDNESDAY...SHIFTING SOUTH OF THE
AREA ON THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
HI PRES RIDGE DRIFTS THRU THE CWA TODAY AND OFFSHORE BY EVE. NLY
FLOW THIS MRNG WILL THEREFORE GRADUALLY VEER TO THE S TODAY. WATER
VAPOR SHOWS A VERY DRY AIRMASS BUILDING OVER THE AREA...SO WILL
FCST MAINLY CLR SKIES THRU TNGT. THE RETURN FLOW HOWEVER WILL
ALLOW FOR INCREASING HUMIDITY DUE TO THE LLVL MOISTURE
INFLUX...AND WITH THE DRY MID LVLS SOME PATCHY FOG WILL BE
POSSIBLE TNGT.

TEMPS WERE CLOSE TO A BLEND OF GUIDANCE AS THE NUMBERS WERE IN
GOOD AGREEMENT. HOWEVER...THERE IS THE POTENTIAL FOR SOME LOCALLY
HIGHER TEMPS TODAY PARTICULARLY OVER LI IF THE OPPOSING NELY FLOW
HOLDS THE SEA BREEZE BACK A BIT. THE NAMDNG SUGGESTS NEAR 80 ALONG
ROUGHLY THE 495 CORRIDOR. AS A RESULT BUMPED UP HIGHS IN THIS AREA
A FEW DEGREES.

&&

.SHORT TERM /SATURDAY/...
DESTABILIZATION BY AFTN ACROSS WRN ZONES WITH SSW FLOW. THIS WILL
AGAIN KEEP ERN PORTIONS OF THE CWA...ESPECIALLY THE
COASTS...STABLE. THE NAM HINTS AT TEMPS REMAINING IN THE 60S
ACROSS THE S SHORE OF LI AND MUCH OF CSTL CT. ALTHOUGH THIS MAY
BE A BIT MUCH...DID LOWER TEMPS IN THIS AREA AND WILL BANK ON A
STABLE AIRMASS. ACROSS THE W...THE MAIN QUESTION WILL BE WHETHER
THERE WILL BE A SUFFICIENT TRIGGER. THE JET WILL BE TOO FAR
UPSTREAM...BUT THE MODELS DO HINT AT SOME SUBTLE MID LVL FORCING.
MAINTAINED THE CURRENT CHC POPS FOR THE AFTN HOURS ACROSS
APPROXIMATELY THE WRN 1/3 OF THE CWA.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
WESTERN ATLANTIC RIDGE WEAKENS SLIGHTLY AT THE START OF THE LONG  
TERM PERIOD SATURDAY NIGHT WITH HEIGHTS BEGINNING TO FALL OVER THE 
AREA. THIS WILL ALLOW A COLD FRONT TO APPROACH FROM THE NORTHWEST. 
THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE NORTH AND 
WEST OF NEW YORK CITY EARLY SATURDAY NIGHT...AND THEN POPS INCREASE 
FROM WEST TO EAST LATE SATURDAY NIGHT AS THE FRONT DRAWS CLOSER. 

THE FRONT SHOULD BE ENTERING THE INTERIOR SUNDAY MORNING AND MOVING 
SOUTH THROUGH THE REMAINDER OF THE AREA DURING THE LATE MORNING AND 
EARLY AFTERNOON HOURS. MODELS GENERALLY AGREE ON THIS SCENARIO 
ALTHOUGH IT IS POSSIBLE THE TIMING SLOWS DOWN IN LATER RUNS AS THE 
MODELS CAN BE TOO FAST MOVING FRONTS SOUTH WITH DEEP RIDGING OFF THE 
COAST. THE FRONT DOES HAVE A GOOD PUSH SOUTH HOWEVER WITH A NEAR 
1030 MB HIGH OVER THE GREAT LAKES REGION AND A SHORTWAVE MOVING 
ACROSS SOUTHEAST CANADA AND NORTHERN NEW ENGLAND. 

POPS INCREASE TO LIKELY FROM NW TO SE ACROSS THE AREA SUNDAY MORNING 
INTO THE AFTERNOON. WITH ABUNDANT CLOUD COVER AND 
PRECIPITATION...INSTABILITY WILL LIKELY BE LOW. HAVE CONTINUED THE 
WORDING FROM PREVIOUS FORECAST WITH SHOWERS LIKELY WITH A CHANCE OF 
THUNDERSTORMS. A DEEP MOISTURE FEED AROUND THE RIDGE TAPPING INTO 
THE GULF OF MEXICO BRINGS HIGH PRECIPITABLE WATERS RANGING FROM 1.5 
TO 1.8 INCHES. LOCALLY HEAVY RAINFALL IS POSSIBLE WITH ANY SHOWERS 
IN THIS AIRMASS. 

SHOWERS CONTINUE SUNDAY NIGHT INTO MONDAY AS THE FRONT STALLS JUST 
SOUTH OF THE AREA. WEAK WAVES OF LOW PRESSURE WILL RIDE ALONG THE 
BOUNDARY. ALOFT...SOME SHORT WAVE ENERGY...AND THE REGION BEING 
LOCATED NEAR THE RIGHT ENTRANCE REGION OF A 80-100 KT UPPER LEVEL 
JET ACROSS NORTHERN NEW ENGLAND AND SOUTHEAST CANADA PROVIDE A 
LARGER SCALE LIFTING MECHANISM. LOCALLY HEAVY RAINFALL REMAINS A 
POSSIBILITY THROUGH AT LEAST MONDAY MORNING. POPS WILL SLOWLY TAPER 
TO HIGH CHANCE IN THE AFTERNOON FOR NORTHERN ZONES...BUT REMAIN 
LIKELY ACROSS THE SOUTH.

POPS CONTINUE TRENDING DOWNWARD MONDAY NIGHT INTO TUESDAY MORNING. 
HOWEVER...MODELS DIFFER ON THE HANDLING OF A MORE WELL DEFINED SHORT 
WAVE AT 500 MB LATE MONDAY NIGHT INTO TUESDAY. THE 00Z ECMWF IS 
SLOWER AND INDICATES A MORE NEUTRAL TILT WHICH ALLOWS WIDESPREAD 
SHOWER ACTIVITY TO CONTINUE WELL INTO TUESDAY. THE GFS AND CMC SHIFT 
THE FRONT FURTHER SOUTH WITH A POSITIVELY TILTED SHORTWAVE QUICKER 
TO MOVE THROUGH. WILL NEED TO SEE IF THE ECMWF IS ON TO SOMETHING AS 
THE NEW 00Z RUN IS CONSISTENT WITH ITS PREVIOUS 12Z RUN. FOR 
NOW...FORECAST SHOWS A LOW CHANCE POPS FOR SOUTHERN ZONES TUESDAY 
MORNING BUT THESE MAY NEED TO BE INCREASED IF THE MODELS COME MORE 
INTO LINE WITH THE ECMWF.

HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY NIGHT THROUGH 
WEDNESDAY...AND THEN SHIFT SOUTH INTO THE WESTERN ATLANTIC ON 
THURSDAY. THIS WILL ALLOW FOR DRIER CONDITIONS TO RETURN. 

TEMPERATURES WILL BE NEAR NORMAL ON SUNDAY...AVERAGE BELOW NORMAL 
MONDAY THROUGH WEDNESDAY...AND BE NEAR NORMAL ON THURSDAY.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE BUILDS DOWN FROM SOUTHEASTERN CANADA THIS
MORNING...THEN MERGES WITH HIGH  PRESSURE OFFSHORE THIS
AFTERNOON. THIS HIGH THEN SLOWLY RETREATS TO THE EAST TONIGHT.

VFR THROUGH THE TAF PERIOD.

WINDS BECOME LIGHT AND VARIABLE THROUGHOUT EARLY THIS
MORNING...THEN BECOME NE AT UNDER 10 KT DURING THE MORNING PUSH.
THE WINDS AGAIN BECOME LIGHT AND VARIABLE LATE THIS MORNING/EARLY
THIS AFTERNOON...BEFORE SE-SSE WINDS SETS UP AT AROUND 10 KT FOR
COASTAL TERMINALS AND AT UNDER 10 KT INLAND. WINDS BECOME LIGHT
AND VARIABLE AGAIN THROUGHOUT THIS EVENING.

.OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...
.LATE FRIDAY NIGHT-SATURDAY MORNING...MVFR OR LOWER
POSSIBLE.
.SATURDAY AFTERNOON...MOST LIKELY VFR. CHANCE OF MVFR IN
SHOWERS/THUNDERSTORMS MAINLY TO THE N/W OF CITY TERMINALS. GUSTS
TO 20-25KT POSSIBLE WITH SEABREEZE.
.SATURDAY NIGHT-TUESDAY MORNING...MVFR OR LOWER AT TIMES.
THUNDERSTORMS POSSIBLE SATURDAY NIGHT-SUNDAY NIGHT.
.TUESDAY AFTERNOON/NIGHT...BECOMING VFR.

&&

.MARINE...
HI PRES WILL KEEP WINDS AND SEAS BLW SCA LVLS THRU TNGT. S FLOW
INCREASES THRU THE DAY ON SAT WITH SCA COND POSSIBLE BY LATE
AFTN...ESPECIALLY THE OCEAN AND S SHORE BAYS.

SCA CONDITIONS ARE LIKELY ON THE OCEAN WATERS FROM SATURDAY NIGHT 
THROUGH TUESDAY. A COLD FRONT WILL BE APPROACHING SATURDAY NIGHT 
WITH STRONG SOUTHERLY FLOW AHEAD OF IT. SEAS ON THE OCEAN WILL BE 
NEAR 5 FT AND WINDS COULD GUST UP TO 25 KT. THE FRONT CROSSES THE 
WATERS ON SUNDAY WITH A STRENGTHENING NE FLOW BEHIND IT. SEAS LIKELY 
BUILD UP TO 7 FEET ON MONDAY AND CONTINUE INTO TUESDAY ON THE
OCEAN.

&&

.HYDROLOGY...
THE POTENTIAL CONTINUES FOR AN EXTENDED SIGNIFICANT WIDESPREAD 
RAINFALL...MAINLY SUNDAY THROUGH MONDAY WITH A COLD FRONT STALLING 
NEAR THE REGION. IT IS DIFFICULT TO SPECIFY EXACT RAINFALL 
AMOUNTS...BUT THERE WILL BE POTENTIAL FOR HEAVY RAINFALL ESPECIALLY 
SUNDAY AND SUNDAY NIGHT INTO MONDAY MORNING WHEN PRECIPITABLE WATERS 
REACH 1.5 TO 1.8 INCHES. ANY HEAVIER SHOWERS PRODUCE LOCALLY HEAVY 
RAINFALL AND THEREFORE AT LEAST MINOR FLOODING OF URBAN/POOR 
DRAINAGE AREAS WILL BE A POSSIBILITY. LOCALIZED FLASH FLOODING 
CANNOT BE RULED OUT.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...JMC/DS
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...DS
AVIATION...MALOIT
MARINE...JMC/DS
HYDROLOGY...DS

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