089
FXUS61 KOKX 202349
AFDOKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
649 PM EST FRI NOV 20 2009
SYNOPSIS
HIGH PRESSURE WILL BUILD EASTWARD FROM THE OHIO VALLEY. THIS HIGH
WILL RESULT IN FAIR AND DRY WEATHER THROUGH SUNDAY. THE
STRENGTHENING HIGH WILL THEN BUILD INTO NORTHERN NEW ENGLAND AND
THE CANADIAN MARITIMES SUNDAY NIGHT INTO MONDAY NIGHT...WHICH MAY
ALLOW WEAK LOW PRESSURE TO SLOWLY MOVE UP THE COAST MONDAY THROUGH
TUESDAY. FAIR WEATHER SHOULD RETURN ON TUESDAY. ANOTHER COASTAL
LOW MAY APPROACH THURSDAY NIGHT INTO FRIDAY.
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
SECONDARY COLD FRONT WELL TO THE EAST ATTM. NW-W WINDS HAVE
DIMINISHED...BUT REMAIN IN THE 5 TO 10 KTS RANGE. THESE WINDS
SUFFICIENT TO PRECLUDE IDEAL RAD COOLING CONDITIONS. SO...IN SPITE
OF MOSTLY CLEAR SKIES...MIN TEMPS TONIGHT WILL BE ON THE WARMER
SIDE OF THE GUIDANCE...RANGING FROM THE 40S IN COASTAL AND URBAN
SECTIONS...TO THE MID/UPPER 30S INLAND. IF WINDS DO FULLY DECOUPLE
LATE TONIGHT...SOME INTERIOR LOCATIONS AND THE LI PINE BARRENS
COULD DROP TO AROUND FREEZING.
SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/
HIGH PRESSURE BUILDING FROM THE OH VALLEY WILL BE IN CONTROL
THROUGH AT LEAST SUNDAY EVENING. DOWNSLOPE FLOW AND MIXING TO
ABOUT 950 MB /2 KFT/ SHOULD BOOST HIGH TEMPS A LITTLE ABOVE MOST
GUIDANCE...WITH LOWER 60S IN URBAN NORTHEAST NJ AND THE CT RIVER
VALLEY...AND MID/UPPER 50S ELSEWHERE. AS THE HIGH BUILDS MORE
SQUARELY OVER THE AREA SAT NIGHT...MINS WILL BE A LITTLE COOLER
AND MORE LIKELY TO BOTTOM OUT AROUND FREEZING INLAND AND IN THE
LONG ISLAND PINE BARRENS...BUT SHOULD REMAIN ABOVE FROST ADVISORY
CRITERIA IN NYC AND HUDSON COUNTY NJ...THE ONLY REMAINING AREAS IN
THE CWA WHERE THE GROWING SEASON HAS NOT YET OFFICIALLY ENDED.
LOSS OF DOWNSLOPE FLOW AND AND LOWER 850-1000 MB THICKNESSES
UNDERNEATH THE HIGH ARGUE FOR HIGH TEMPS A FEW DEGREES COOLER THAN
THOSE OF SAT BUT STILL A TOUCH ABOVE GUIDANCE...MAINLY LOWER AND
MID 50S.
FORECAST UNCERTAINTIES BEGIN TO CREEP IN DURING SUN NIGHT-MON
REGARDING THE APPROACH OF A WEAK COASTAL LOW. HIGH PRESSURE
PASSING TO THE NORTH OF THE AREA BECOMES VERTICALLY STACKED AND
STRENGTHENS SUN NIGHT-MON...WHICH MAY SUPPRESS THE LOW ENOUGH TO
MAINTAIN FAIR WX. NAM/ECMWF AN SOME GEFS MEMBERS SUPPORT THIS
IDEA...WHILE THE OPERATIONAL GFS AND CANADIAN GGEM REMAIN WET.
HAVE BACKED OFF EARLIER LIKELY POP...BUT WITH THE AXIS OF SURFACE
RIDGING NORTH OF THE AREA AND MAINTAINING A LOW LEVEL ONSHORE
FLOW...AND A MID LEVEL SHORTWAVE UNDERCUTTING THE HIGH...THINK
CHANCE POP IS STILL IN ORDER FOR MON...ESPECIALLY IN
THE AFTERNOON.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
MODELS LACK CONSISTENCY RIGHT FROM THE BEGINNING OF THE PERIOD ON
THE STRENGTH OF THE SOUTHERN STREAM CLOSED LOW SHEARING NE MON
NIGHT...AND DISPLACEMENT OF STACKED RIDGING. THIS IS RESULTING IN
DIFFERENCES IN THE NORTHWARD TRACK AND STRENGTH OF THE SURFACE
LOW. WITH THIS UNCERTAINTY HAVE HELD POP TO CHANCE FOR MON NIGHT.
FORECAST DETAILS CONTINUE SHAKY THEREAFTER...WITH UNCERTAINTY IN
PROGRESSION OF PACIFIC SHORTWAVE FEATURES INTO THE LOWER 48.
MODELS HINT AT A PERIOD OF RIDGING TUE INTO WED AS UPPER ENERGY
DIGS OVER THE CENTRAL STATES...WITH LATE A WEEK COASTAL SYSTEM
POSSIBLE AS UPPER ENERGY WORKS TOWARD THE COAST. HAVE CONTINUED
WITH CHANCE POP FOR THIS PERIOD WITH UNCERTAINTY.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
VFR AS HIGH PRESSURE BUILDS INTO THE REGION THROUGH SATURDAY.
WEST/NW WINDS WILL REMAIN AROUND 5 TO 10 KTS...AND THIS WILL CONTINUE
SATURDAY.
OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY...
SAT: VFR.
SUN: VFR.
SUN NIGHT-MON: SUB-VFR.
TUE AND WED...VFR LIKELY.
MARINE
SEAS REMAIN ABOVE 5 FT E OF FIRE ISLAND INLET WITH FREQUENT GUSTS
TO 25 KT...SO SCA CONTINUES THERE. OTHERWISE...SUB SCA CONDITIONS
EXPECTED AS WINDS SLOWLY DIMINISH OVERNIGHT.
QUIET CONDITIONS SHOULD THEN BE THE RULE WITH HIGH PRESSURE IN
CONTROL UNTIL LATE SUN NIGHT-MON NIGHT...WHEN INCREASING EASTERLY
FLOW BETWEEN STRONG HIGH PRESSURE TO THE NORTHEAST AND A COASTAL
LOW TO THE SOUTH COULD YIELD SCA CONDITIONS.
WINDS SHOULD DIMINISH ON TUE AS HIGH PRESSURE BUILDS BACK IN...
WITH SEAS SUBSIDING BELOW SCA THROUGH WED.
HYDROLOGY
SPREAD IN MODEL QPF IS QUITE LARGE FOR POSSIBLE COASTAL SYSTEM
SUNDAY NIGHT-MON NIGHT...WITH SUPPRESSED SOLUTIONS VIRTUALLY DRY
AND STRONGER/WETTER SOLUTIONS BRINGING OVER AN INCH ESPECIALLY TO
NYC METRO. CURRENT FORECAST LEANS TOWARD THE DRIER SIDE OF THE
ENVELOPE...SO HYDROLOGIC/FLOODING ISSUES APPEAR UNLIKELY ATTM.
OKX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ350-353.
SYNOPSIS...BG/PW
NEAR TERM...BG/PW
SHORT TERM...BG
LONG TERM...NV
AVIATION...PW
MARINE...BG/NV/PW
HYDROLOGY...BG/NV
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