000
FXUS61 KOKX 111432
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
932 AM EST THU MAR 11 2010

.SYNOPSIS...
HIGH PRESSURE WILL STRENGTHEN OVER EASTERN CANADA THROUGH FRIDAY.
LOW PRESSURE WILL APPROACH THE REGION SATURDAY AND SUNDAY. THE LOW
WILL TRACK EAST OF THE REGION ON MONDAY. HIGH PRESSURE WILL BUILD
WEST OF THE REGION TUESDAY AND WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT MUCH SEEN ON RADAR ATTM. WEAK LOW LEVEL FORCING AND
MOISTENING BOUNDARY LAYER WILL RESULT IN CLOUDS ALONG WITH
POSSIBLE LIGHT RAIN SHOWERS OR SPRINKLES THROUGH THE DAY. TEMPS
THUS WILL REMAIN GENERALLY IN THE 50S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
WEAK MOISTURE ADVECTION WILL CONTINUE. FORCING IS LIMITED SO
CHANCE TO SLIGHT CHANCE POPS FOR LIGHT RAIN. A BLEND OF GMOS AND
MET WAS USED FOR HIGH TEMPERATURES. CHANCES FOR DRIZZLE WILL
INCREASE THIS EVENING AS THE BOUNDARY LAYER BEGINS TO COOL.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
500 MILLIBAR LOW CURRENTLY OVER EASTERN KANSAS WILL BECOME NEARLY
STATIONARY TONIGHT. THE LOW WILL BEGIN TO TRANSLATE EASTWARD ON
FRIDAY AS A SHORTWAVE TROUGH CURRENTLY OVER THE SOUTHWESTERN
UNITED STATES ENCOUNTERS THE SUBTROPICAL JET STREAM AND THE THREE
SYSTEMS COME TOGETHER. WATER VAPOR SHOWS THAT THE MOISTURE ALONG
THE SUBTROPICAL JET STREAM EXTENDS FROM THE WESTERN PACIFIC
OCEAN...ACROSS MEXICO AND THE GULF OF MEXICO...AND UP THE EASTERN
SEABOARD ON THE DOORSTEP OF THE FORECAST AREA.

ALL MODELS INDICATE THAT THE FORECAST AREA WILL BETWEEN HIGH
PRESSURE OVER EASTERN CANADA AND THE APPROACHING MULTIPLE SURFACE
LOWS FROM THE SOUTH AND SOUTHWEST TODAY THROUGH FRIDAY. THIS WILL
RESULT IN A STEADY INCREASE IN EASTERLY WINDS. THE EAST WINDS WILL
BRING INCREASED LOW LEVEL MOISTURE...RESULTING IN POCKETS OF
LIGHT RAIN TODAY AND LIGHT RAIN AND DRIZZLE INCREASING IN COVERAGE
TONIGHT AND FRIDAY. IT WILL REMAIN CLOUDY WITH INCREASING LOW
CLOUD COVERAGE AND A CANOPY OF HIGH CLOUDS PROVIDED BY THE
SUBTROPICAL JET STREAM. THE ONSHORE FLOW AND CLOUDS SHOULD RESULT
IN COOLER TEMPERATURES DURING THE DAY ALONG THE COAST AND COOLER
TEMPERATURES AT NIGHT ACROSS THE INTERIOR. A BLEND OF
GMOS...MET...GFS 2 METER TEMPERATURES AND NAM 2 METER TEMPERATURES
WERE USED FOR THE FORECAST. POPS WERE A BLEND OF GMOS AND THE
SREF. QPF WAS A BLEND OF THE SREF AND GFS.

AS THE UPPER LEVEL LOW REACHES THE OHIO VALLEY...MOISTURE AND
FORCING INCREASE AND MODERATE TO HEAVY RAIN DEVELOP. THE 00Z RUNS
OF THE GFS AND ECMWF WERE VERY CLOSE IN THE TIMING OF THE
HEAVY PRECIPITATION. AT THIS TIME...THE DATA SUGGEST THE HEAVY
RAIN WILL SPREAD FROM SOUTHWEST TO NORTHEAST SATURDAY AND SATURDAY
NIGHT. 850 MILLIBAR MOISTURE TRANSPORT VECTORS SHOW STRONG
MOISTURE ADVECTION INTO THE CWA. BECAUSE THE 500 MILLIBAR LOW WILL
TRACK EASTWARD...LOW PRESSURE JUST SOUTH OF THE FORECAST AREA AND
THE ASSOCIATED WARM FRONT NEARLY STALL. AREAS NORTH OF THE WARM
FRONT WILL BE IN THE STRONG EASTERLY WIND CORRIDOR...WITH
BOUNDARY LAYER PROJECTIONS FROM THE NAM AND GFS REACHING 50 KNOTS
OR GREATER. THE EXACT NORTHWARD TRACK OF THE SURFACE LOW IS STILL
UNRESOLVED THIS FAR OUT...BUT THE WARM FRONT WILL HAVE THE BEST
CHANCE TO PENETRATE NORTHWARD THROUGH LONG ISLAND AND POSSIBLY
SOUTHEASTERN CONNECTICUT SUNDAY MORNING...BEFORE ANOTHER SURFACE
LOW IS INDUCED OFF THE NEW JERSEY COAST...RESULTING IN A RETURN TO
NORTHERLY COMPONENT LOW LEVEL FLOW. HOURLY POPS WERE USED TO TRY
TO PIN DOWN THE TIMING OF THE MOST SIGNIFICANT RAINFALL. A BLEND
OF THE SREF AND GFS WAS USED. DIURNAL TEMPERATURE SWINGS WILL BE
MINIMIZED DUE TO THE CLOUDS AND PRECIPITATION. NAM AND GFS 2 METER
TEMPERATURES WERE THEREFORE BLENDED WITH GUIDANCE EVEN AT NIGHT.
AS FAR AS WIND SPEEDS...FORECAST WILL BRING SUSTAINED WINDS AT OR
ABOVE WIND ADVISORY CRITERIA FOR ALL BUT NORTHWEST INTERIOR
ZONES. THE POTENTIAL EXISTS FOR HIGH WIND CRITERIA GUSTS...GIVEN
THAT THE BOUNDARY LAYER WINDS ARE AS STRONG AS PREVIOUSLY
MENTIONED.

PRECIPITATION RATES DECREASE ON SUNDAY AS THE STRONG MOISTURE
ADVECTION IS CUT OFF. AS THE SECOND SURFACE LOW TAKES OVER...THE
ECMWF STILL PRODUCES A SWATH OF MODERATE PRECIPITATION SUNDAY
NIGHT IN AN AREA OF MID LEVEL FRONTOGENESIS. HAVE KEPT POPS ABOVE
GMOS FOR THIS AS THE ECMWF HAS BEEN CONSISTENT. WILL HAVE TO WATCH
FOR PRECIPITATION TYPE WITH THE UPPER LEVEL LOW COOLING THE
COLUMN. COULD BE A MIX OR CHANGE TO SNOW ACROSS THE INTERIOR WITH
LIGHT ACCUMULATIONS POSSIBLE. STILL TOO EARLY AND MORE MODEL
CONSISTENCY IS NEEDED. TEMPERATURES WERE HELD CLOSER TO THE
PREVIOUS GFS ENSEMBLES TO ACCOUNT FOR ADDITIONAL CLOUDS AND
PRECIPITATION THAT ARE NOT IN THE OPERATIONAL 00Z GFS RUN.

WITH THE UPPER LEVEL LOW SLOWLY DEPARTING ON
MONDAY...PRECIPITATION CHANCES WILL SLOWLY DIMINISH TO DRY AFTER
MIDNIGHT MONDAY NIGHT. 850 MILLIBAR TEMPERATURES 2 TO 3 DEGREES
CELSIUS TUESDAY SO MAINTAINED THE MILD HIGH TEMPERATURES. AN UPPER
LEVEL TROUGH MAY DROP HEIGHTS FOR WEDNESDAY. LOW LEVEL FLOW
HOWEVER APPEARS TO BE CONDUCIVE TO CONTINUED GOOD MIXING SO
TEMPERATURES ARE FORECAST TO BE MILD. DRY TUESDAY AND WEDNESDAY PER
LATEST 00Z GFS AND ECMWF.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
GENERALLY VFR. THE BIG CHALLENGE IS WILL THERE BE ENOUGH DRY AIR
BENEATH AN INVERSION BASED AROUND 950 MB TO BE ABLE TO SCT OUT THE
MVFR CIGS ACROSS THE NYC TERMINALS. RIGHT NOW THIS IS BEING HANDLED
AS OCCASIONAL MVFR CIGS THIS MORNING...BUT THERE IS ENOUGH UNCERTAINTY
THAT THIS COULD LINGER THROUGH THE DAY. CEILINGS THEN LOWER AFTER
04Z...BECOMING IFR WITH DRIZZLE POSSIBLE. TIMING OF LOWERING CEILINGS
UNCERTAIN AS WILL DEPEND ON FRONTAL BOUNDARY MOVING INTO THE REGION.
HIGH PRESSURE TO THE NORTH MAY HOLD FRONT FARTHER SOUTH.

EASTERLY FLOW MUCH OF THE PERIOD WITH WINDS UNDER 10 KT. WINS
INCREASE TO AROUND 10 KT TOWARD THE END OF THE FORECAST PERIOD.

KJFK AFTN HOURLY WIND FORECAST IN SUPPORT OF RUNWAY CONSTRUCTION
ALL WIND DIRECTIONS ARE TRUE...ADD 13 DEGREES FOR MAGNETIC
     11/19Z 09008KT
     11/20Z 09008KT
     11/21Z 09008KT
     11/22Z 09007KT
     11/23Z 09007KT
     12/00Z 09007KT
     12/01Z 09007KT
     12/02Z 09008KT
     12/03Z 09008KT


OUTLOOK 12Z FRIDAY THROUGH MONDAY...
FRIDAY THROUGH SATURDAY NIGHT...IFR IN RAIN AND FOG. INCREASING
EASTERLY FLOW WITH 30 PLUS KT GUSTS FRIDAY NIGHT INTO SATURDAY
NIGHT. LLWS ALSO LIKELY.
SUNDAY THROUGH MONDAY...EARLY IFR CONDITIONS LIKELY WITH LINGERING
RAIN SUNDAY MORNING...THEN CONDITIONS IMPROVING TO VFR. DIMINISHING
WINDS SUNDAY NIGHT THROUGH MONDAY.

&&

.MARINE...
A SLOW MOVING STORM SYSTEM ACROSS THE CENTRAL UNITED STATES WAS
GENERATING A PERSISTENT EASTERLY FLOW. THIS FLOW WILL STEADILY
INCREASE TODAY INTO SATURDAY AS THE STORM SYSTEM DEEPENS AND
TRACKS EAST. DURING THE DAY FRIDAY SMALL CRAFT CONDITIONS WILL
LIKELY DEVELOP ON THE OCEAN WATERS AND POSSIBLY ON THE EASTERN
SOUND. BY FRIDAY EVENING GUSTS ON THE OCEAN WATERS WILL POSSIBLY
INCREASE TO GALE FORCE WITH SMALL CRAFT GUSTS ACROSS THE REST OF
THE FORECAST WATERS...AND BY SATURDAY GALE FORCE GUSTS WILL BE
POSSIBLE ON ALL THE AREA WATERS. THE DEVELOPMENT OF THE GUSTS WILL
DEPEND ON HOW QUICKLY A LOW LEVEL INVERSION IS ERODED AND HOW DEEP
MIXING OVER THE WATERS BECOMES. IF MIXING BECOMES DEEPER THERE IS
THE POTENTIAL TO MIX DOWN 50 TO 60 KT WINDS FRIDAY NIGHT INTO
SATURDAY.

AS THE LOW SLOWLY DRIFTS EAST SUNDAY INTO MONDAY...THE FLOW WILL
WEAKEN AND GRADUALLY BACK NORTHERLY. CONDITIONS SHOULD IMPROVE
SUNDAY AFTERNOON INTO SUNDAY NIGHT. HOWEVER...LINGERING SWELLS
SHOULD KEEP OCEAN SEAS WELL ABOVE SMALL CRAFT LEVELS THROUGH AT
LEAST MONDAY.

&&

.HYDROLOGY...
HEAVY RAIN WILL BEGIN ACROSS THE WESTERN PORTION OF THE FORECAST
AREA BY SATURDAY MORNING AND SPREAD NORTHEASTWARD THROUGH SATURDAY
NIGHT. DEEP MOISTURE WILL BE FED OVER A NEARLY STATIONARY FRONTAL
BOUNDARY AS LOW PRESSURE SLOWLY TRACKS NORTHWARD TOWARDS THE AREA.
URBAN AND POOR DRAINAGE FLOODING CAN BE EXPECTED. RIVERS AND
STREAMS WILL BE SUSCEPTIBLE TO FLOODING AS WELL. A FLOOD WATCH CAN
BE EXPECTED AS WE DRAW CLOSER TO THE EVENT.

&&

.TIDES/COASTAL FLOODING...
A PERSISTENT EASTERLY FLOW...STEADILY INCREASING TODAY THROUGH
SATURDAY...AND INCREASING ASTRONOMICAL TIDES DURING TO AN
APPROACHING NEW MOON...WILL RESULT IN THE POTENTIAL FOR WIDESPREAD
MINOR COASTAL FLOODING DURING THE HIGH TIDE CYCLE SATURDAY NIGHT
WITH TIDAL DEPARTURES OF 2 TO 2 1/2 FEET. MORE WIDESPREAD MINOR TO
LOCALLY MODERATE COASTAL FLOODING...ESPECIALLY IN LONG ISLAND
SOUND...IS LIKELY SUNDAY MORNING WITH TIDAL DEPARTURES OF 3 TO 4
FEET POSSIBLE.

IN ADDITION...BEACH EROSION IS ANOTHER POTENTIAL PROBLEM FOR THE
SOUTH SHORE BEACHES WITH HIGH SURF FROM EASTERLY SWELLS. SEAS ON THE
OCEAN ARE FORECAST TO RANGE FROM 15 TO 18 FEET SATURDAY NIGHT INTO
SUNDAY.

&&

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

&&

$$

SYNOPSIS...JMC
NEAR TERM...PW
SHORT TERM...JMC
LONG TERM...JMC
AVIATION...MET
MARINE...MET
HYDROLOGY...JMC
TIDES/COASTAL FLOODING...MET

NWS OKX Office Area Forecast Discussion