AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
248 PM EDT THU JUL 7 2011

.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN NEARLY STATIONARY ACROSS THE REGION
TODAY...THEN SLOWLY DRIFT SOUTH OF LONG ISLAND TONIGHT. HIGH
PRESSURE PASSES NORTH OF THE REGION TONIGHT...THEN LOW PRESSURE
APPROACHES FROM THE SOUTH ON FRIDAY. AN AREA OF LOW PRESSURE
TRACKS TO OUR SOUTH ALONG A STALLED FRONTAL BOUNDARY FRIDAY
NIGHT...AS A WAVE OF LOW PRESSURE TRACKS ALONG THE FRONT. HIGH
PRESSURE THEN BUILDS IN FOR THE WEEKEND...SLIDING OFFSHORE SUNDAY
NIGHT. A COLD FRONT APPROACHES FROM THE WEST MONDAY...THEN CROSSES
THE AREA MONDAY NIGHT AND EARLY TUESDAY. HIGH PRESSURE THEN BUILDS
IN THROUGH THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
1830Z UPDATE...QUICK UPDATE MADE AS SCATTERED SHOWERS HAVE
DEVELOPED OVER WRN NJ AND ARE APPROACHING NE NJ. ALSO ISOLATED
SHOWERS HAVE DEVELOPED OVER SRN MIDDLESEX AND NEW LONDON COUNTIES. INCREASED
POPS TO LIKELY OVER PORTIONS OF NE NJ AND STATEN ISLAND. SOME
THUNDER POSSIBLE AS WELL.

WITH A RELATIVELY DRY ATMOSPHERE IN THE LOWER LEVELS AND AN
"INVERTED-V" SOUNDING...WILL ALSO MENTION THAT THUNDERSTORMS WILL
BE CAPABLE OF GUSTY WINDS.

THERE IS A MODERATE RISK FOR RIP CURRENTS AT OCEAN-FACING BEACHES
TODAY.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
STATIONARY BOUNDARY BARELY MOVES THROUGH THIS PERIOD...AND
SEVERAL WAVES OF LOW PRES WILL APPROACH FROM THE WEST. THE FIRST
WAVE WILL APPROACH TONIGHT. WILL CARRY LOW CHANCE POPS FOR
WESTERN ZONES...AS SHOWERS AND THUNDERSTORMS WILL BEGIN TO MOVE
INTO THE REGION AFTER MIDNIGHT TONIGHT. ANOTHER WAVE OF LOW PRES
APPROACHES FRI AFTERNOON. WILL BUMP UP POPS TO LIKELY FOR MUCH OF
THE REGION LATE IN THE DAY.

LOWS TONIGHT WILL DROP INTO THE UPPER 60S TO AROUND 70 FOR NYC
AND NEARBY SUBURBS...AND INTO THE MID TO UPPER 60S FOR COASTAL
AREAS. ACROSS THE INTERIOR...LOWS WILL DROP INTO THE LOW TO MID
60S.

WITH ABUNDANT CLOUD COVER ON FRI...AND SHOWERS/THUNDERSTORMS
MOVING INTO THE REGION IN THE AFTERNOON...HIGHS WILL TOP OFF IN
THE MID TO UPPER 70S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THERE IS A BIT OF UNCERTAINTY ON THE EXACT TRACK AND STRENGTH OF
AN AREA OF LOW PRESSURE THAT WILL LIFT NORTHEAST ALONG A COLD
FRONT TRACKING TO OUR SOUTH FRIDAY NIGHT. THE ECMWF IS FARTHEST N
AND STRONGEST WITH THE LOW...THE NAM FARTHEST S. FOR NOW WENT WITH
A COMPROMISE SOLUTION THAT IS FAIRLY CLOSE TO THE GFS. FOR NOW
THERE ARE INDICATIONS OF ENOUGH SURFACE TO MID LEVEL INSTABILITY
TO GO WITH SHRA/TSRA...BUT IF THE ECMWF ENDS UP BEING
CORRECT...COULD END UP MORE A SOAKING RAIN WITH EMBEDDED
CONVECTION. FOR POPS WENT WITH LIKELY ACROSS SOUTHERN ZONES AND
HIGH CHANCE N. USED A MAV/MET BLEND PLUS A DEGREE TO WEIGH TOWARDS
WARMER GUIDANCE FOR LOWS.

500 HPA TROUGH CROSSES THE AREA SATURDAY...DO HAVE SLIGHT CHANCE
POPS SATURDAY MORNING TO REFLECT ITS PASSAGE...WITH DEVELOPING
15-25 KT OF NW FLOW IN THE AFTERNOON ON THE BACKSIDE OF THE
TROUGH HELPING TO DRY OUT THE LOW LEVELS...WENT DRY IN THE
AFTERNOON. FOR HIGHS...FOR NOW SIDED WITH WARMER MAV GUIDANCE...AS
NAM/ECMWF ARE IN A MINORITY COMPARED TO OTHER MODELS AND ENSEMBLES
IN DEPTH OF TROUGH AND AMOUNT OF LOW LEVEL RELATIVELY COOLER AIR
COMING DOWN WITH IT...WITH HIGHS SLIGHTLY ABOVE NORMAL EXPECTED.

RIDGING BUILDS IN FROM THE MID MISSISSIPPI VALLEY SATURDAY NIGHT
THROUGH MONDAY...WITH THE REGION UNDER WNW FLOW ALOFT ON THE
NORTHERN PERIPHERY OF THE RIDGE. SHOULD HAVE DRY CONDITIONS DUE TO
SUBSIDENCE ASSOCIATED WITH THE RIDGE THROUGH MONDAY MORNING. AN
APPROACHING 500 MB NORTHERN STREAM TROUGH MONDAY AFTERNOON
WARRANTS SLIGHT CHANCE POPS THEN. 850 TEMPERATURES INCREASING TO
18-20C BY MONDAY WILL SPELL INCREASINGLY WARMER CONDITIONS IN THIS
TIME FRAME...WITH SOUTHERLY FLOW BRINGING INCREASING HUMIDITY AS
WELL. USED A MEX/MEX ENSEMBLE MEAN BLEND FOR TEMPERATURES. WITH
TEMPERATURES 5-10 DEGREES ABOVE NORMAL EXPECTED.

FOR MONDAY NIGHT-WEDNESDAY THE GFS AND ECMWF DIFFER ON HOW
QUICKLY A COLD FRONT PUSHES TO THE S IN THIS TIME FRAME DUE TO
DIFFERENCES IN FORECAST EVOLUTION OF THE CANADIAN HIGH BUILDING IN
BEHIND IT. WHILE IN GENERAL THE ECMWF PERFORMS BETTER THIS FAR
OUT...A RECENT TREND HAS BEEN THAT WHEN THE GFS IS SLOWER THAN THE
ECMWF...GIVEN THE GFS PROGRESSIVE BIAS...THAT THE GFS ACTUALLY HAS
PROVED BETTER. WORKING AGAINST THE GFS IN THIS TIME FRAME IS THAT
THE MODEL IS TYPICALLY TOO WEAK WITH HIGH PRESSURE BUILDING DOWN
FROM CANADA...EVEN WITH DECENT CONFLUENCE ALOFT SUPPORTING IT AS
IS THE CASE NOW...MEANING THAT THE GFS FRONTAL POSITION IS LIKELY
TO FAR N DURING THIS PERIOD. GIVEN THE CONTRARY INDICATIONS ON
WHICH SOLUTION TO FAVOR...OPTED FOR A BLEND OF THE TWO SOLUTIONS
FOR NOW.

THE RESULT IS WENT WITH CHANCE POPS WITH THE FRONT FROM MONDAY
NIGHT INTO TUESDAY...THEN DRY TUESDAY NIGHT AND WEDNESDAY. USED A
MEX/MEX ENSEMBLE MEAN BLEND TWEAKED TOWARDS A BLEND OF GFS/ECMWF
LOW LEVEL THERMAL FIELDS FOR TEMPERATURES. EXPECT VALUES TO BE A
FEW DEGREES ABOVE NORMAL AS A RESULT.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
A WEAK FRONTAL BOUNDARY WILL SLOWLY SETTLE JUST TO OUR SOUTH
TONIGHT AND FRIDAY.

VFR THIS AFTERNOON...EXCEPT IN ANY SHOWER/TSTM ACTIVITY. ISOLATED
TO SCATTERED TSTMS ARE EXPECTED TO DEVELOP THIS AFTERNOON. CB/S
CARRIED FOR ALL TERMINALS. AGAIN GENERALLY VFR...HOWEVER
RESTRICTIONS POSSIBLE IN THE VICINITY OF CONVECTION. WIND GUST
POTENTIAL IN ANY TSTMS THIS AFTERNOON. WILL MONITOR ANY
THUNDERSTORM DEVELOPMENT AND MOVEMENT.

POTENTIAL FOR MVFR OR LOWER AFTER 0-3Z AS LOW LEVEL MOISTURE POOLS
OVER THE AREA. STRATUS AND FOG POSSIBLE. UPPER LEVEL SYSTEM
APPROACHES AND BRINGS INCREASED CHANCES FOR TSTMS OVERNIGHT. WILL
INCLUDE SHOWERS IN TERMINAL FORECAST BY FRIDAY MORNING AS I
EXPECT COVERAGE TO BE HIGHER AT THAT TIME.

AS FOR WINDS...LIGHT AND VARIABLE FLOW WITH FRONT IN OUR VICINITY.
SEA BREEZES HAVE DEVELOPED...AND WILL NEED TO WATCH TIMING FOR
KLGA AND KEWR. WINDS EAST/NE TONIGHT...AND VERY LIGHT. EAST TO
SOUTHEAST FRIDAY MORNING...REMAINING LIGHT.

     NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT:  HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KEWR FCSTER COMMENTS: VARIABILITY IN WIND DIRECTION EXPECTED DUE
TO THE PROXIMITY OF THE FRONT. SEA BREEZE COULD APPROACH AIRPORT
AFTER 19 OR 20Z. AS SUCH...AMENDMENTS POSSIBLE. A SHOWER OR TSTM
IS NOT OUT OF THE QUESTION.

KJFK FCSTER COMMENTS: SEA BREEZE SHOULD CONTINUE THROUGH THE
AFTERNOON BEFORE WINDS LIGHTEN. A SHOWER OR TSTM IS NOT OUT OF
THE QUESTION.

KLGA FCSTER COMMENTS: NORTHEAST WIND OFF THE SOUND SHOULD CONTINUE
THROUGH 3 PM. THEREAFTER...SEA BREEZE COULD APPROACH AIRPORT.
AS SUCH...AMENDMENTS POSSIBLE. A SHOWER OR TSTM IS NOT OUT OF THE
QUESTION.

KTEB FCSTER COMMENTS: VARIABILITY IN WIND DIRECTION EXPECTED DUE
TO THE PROXIMITY OF THE FRONT. SEA BREEZE COULD APPROACH AIRPORT
AFTER 20Z. AS SUCH...AMENDMENTS POSSIBLE. A SHOWER OR TSTM IS NOT
OUT OF THE QUESTION.

KHPN FCSTER COMMENTS: VARIABILITY IN WIND DIRECTION EXPECTED DUE
TO THE PROXIMITY OF THE FRONT. SEA BREEZE HAS APPROACHED THE
AIRPORT. AS SUCH...AMENDMENTS POSSIBLE. A SHOWER OR TSTM IS NOT
OUT OF THE QUESTION.

KISP FCSTER COMMENTS: VARIABILITY IN WIND DIRECTION EXPECTED DUE
TO THE PROXIMITY OF THE FRONT. SEA BREEZE HAS APPROACHED THE
AIRPORT. AS SUCH...AMENDMENTS POSSIBLE. A SHOWER OR TSTM IS NOT
OUT OF THE QUESTION.

OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...

FRI AFTERNOON-FRI NIGHT...SUB VFR IN TSTMS LIKELY.
SAT...IMPROVING CONDITIONS BEHIND A FRONT.
SUN-MON...VFR.
TUE...CHANCE OF MVFR OR LOWER IN THE MORNING. TSTMS POSSIBLE
AHEAD OF A COLD FRONT.

&&

.MARINE...
1130Z UPDATE...MINOR CHANGES TO FIRST FEW HOURS OF MARINE GRIDS
BASED ON LATEST OBS/6Z GUIDANCE...WITH THE FORECAST OVERALL
SEEMING ON TRACK.

AFTERNOON CONVECTION POSSIBLE TODAY...OTHERWISE...WINDS/WAVES WILL
BE TRANQUIL THROUGH FRI. A 2-FT SWELL WITH 15-SECOND PERIOD COULD
MAKE FOR ROUGH CONDITIONS AT THE OCEAN INLETS THROUGH TONIGHT.

A WAVE OF LOW PRES APPROACHES ON FRI...AND CHANCES FOR CONVECTION
INCREASES THROUGHOUT THE AFTERNOON. WINDS/WAVES WILL REMAIN BELOW
SCA CRITERIA.

WITH A RELATIVELY LIGHT PRESSURE GRADIENT OVER THE REGION FRIDAY
NIGHT THROUGH MONDAY...EXPECT CONDITIONS TO GENERALLY REMAIN BELOW
SMALL CRAFT CONDITIONS IN THIS TIME FRAME. THE ONE EXCEPTION COULD
BE OVER FAR EASTERN COASTAL WATERS SATURDAY NIGHT...WHERE A
COMBINATION OF SWELL AND UP TO 10 KT OF OPPOSED WINDS COULD BUILD
SEAS TO UP TO 5 FT THERE.

&&

.HYDROLOGY...
NO SIGNIFICANT WIDESPREAD PRECIPITATION IS EXPECTED AT THIS TIME.
LOCALLY HEAVY RAINFALL IS HOWEVER POSSIBLE WITH ANY STRONGER
CONVECTION. HOWEVER...IF THE ECMWF ENDS UP BEING CORRECT WITH THE
STRENGTH AND LOCATION OF THE COASTAL LOW TRACKING TO OUR S FRIDAY
NIGHT...THERE IS THE POTENTIAL FOR A SOAKING RAIN OF 0.5-1
INCH...WITH LOCALLY HIGHER AMOUNTS IN STRONGER EMBEDDED
CONVECTION. WHILE THIS DOES NOT APPEAR LIKELY...THE POSSIBILITY IS
HIGH ENOUGH THAT IT WARRANTS WATCHING AT THIS TIME.

&&

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

&&

$$