FXUS61 KOKX 010603
AFDOKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
103 AM EST TUE DEC 1 2009
.SYNOPSIS...
RAIN IN ASSOCIATION WITH AN ADVANCING COLD FRONT WILL END THIS
EVENING. HIGH PRESSURE WILL THEN BUILD TO THE SOUTH LATER TONIGHT
INTO TUESDAY...WHILE A WARM FRONT PASSES JUST TO THE NORTH.
THE HIGH WILL MOVE EAST OF THE AREA WEDNESDAY AFTERNOON.
STRENGTHENING LOW PRESSURE OVER THE GULF COAST STATES WILL THEN
MOVE NORTHEAST TOWARD THE LOWER GREAT LAKES WEDNESDAY NIGHT INTO
THURSDAY...WITH WINDY AND RAINY CONDITIONS AS ITS TRAILING FRONTAL
SYSTEM CROSSES THROUGH THE LOCAL AREA. HIGH PRESSURE WILL RETURN
LATER THURSDAY INTO FRIDAY NIGHT. ANOTHER STORM MAY IMPACT THE
AREA ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WITH LIFT BEHIND THE COLD FRONT SLOW TO MOVE OFFSHORE HAVE UPDATED
THE GRIDS TO DELAY THE END OF THE RAIN BY A FEW HOURS...UNTIL LIFT
MOVES OFFSHORE. RAIN ENDS AND IS FOLLOWED BY A QUICK SHOT OF
CAA...WITH GUSTY NW WINDS ESPECIALLY IN URBAN/COASTAL
SECTIONS...CLEARING SKIES...AND TEMPS DROPPING INTO THE 30S IN
MOST PLACES...PERHAPS SOME ISOLATED UPPER 20S WELL INLAND.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
WEAK WARM FRONT PASSES NORTH OF THE AREA ON TUE WHILE HIGH
PRESSURE BUILDS TO THE SOUTH INITIALLY. INCREASING LOW LEVEL
MOISTURE AND VEERING 700-900 MB WINDS INDICATIVE OF WEAK
ISENTROPIC LIFT COULD RESULT IN SOME SHOWERS/SPRINKLES MAINLY
FROM LATE MORNING INTO EARLY AFTERNOON...AND HIGHER ELEVATIONS
NORTH/WEST COULD SEE SOME WET SNOWFLAKES MIXED IN. AFTER THIS
FEATURE MOVES THROUGH...THE HIGH WILL BUILD MORE SQUARELY INTO THE
AREA THROUGH EARLY WED AFTERNOON...WITH CLEARING SKIES AND TEMPS
NEAR NORMAL.
LOW PRESSURE ORGANIZING OVER THE GULF STATES WILL THEN IMPACT THE
AREA FROM WED NIGHT INTO THU AS IT MOVES NE TOWARD THE LOWER GREAT
LAKES. GFS/ECMWF COMING TOGETHER IN TERMS OF A COMMON SOLUTION
SHOWING A LITTLE LESS PHASING WITH A DEEPENING NORTHERN STREAM
TROUGH...BUT WITH THE GFS STILL 10 MB DEEPER BY THU MORNING AND A
LITTLE FASTER. CLOUDS IN ADVANCE OF THE SYSTEM SHOULD BEGIN TO
LOWER/THICKEN LATE WED AFTERNOON...WITH SLIGHT CHANCE POP FOR ALL
BUT EASTERN CT/LONG ISLAND BY LATE DAY OR EARLY EVENING...THEN
WIDESPREAD CATEGORICAL/LIKELY POP AND RISING TEMPS WED NIGHT/THU
MORNING AS A 70-KT SOUTHERLY LOW LEVEL JET TRANSPORTS
GULF/ATLANTIC MOISTURE NORTHWARD AHEAD OF AN ADVANCING WARM
FRONT. THE LLJ AND A TIGHT PRESSURE GRADIENT BETWEEN THE INLAND
LOW AND HIGH PRESSURE OVER THE ATLANTIC COULD BRING ADVISORY
CRITERIA WINDS TO NYC...COASTAL SECTIONS AND THE HIGHER INLAND
ELEVATIONS. IT IS STILL UNCLEAR HOW MUCH AN EXPECTED LOW LEVEL
INVERSION WILL ACT TO PREVENT THIS. A RUMBLE OF THUNDER WOULD NOT
BE SURPRISING AHEAD OF COLD FROPA ON THU...BUT PROBABILITY ATTM
TOO LOW TO INCLUDE IN FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
DECENT MODEL AGREEMENT IN THE FIRST PART OF THE LONG TERM...HOWEVER
MODEL DIFFERENCES POP UP DURING THE WEEKEND. HIGH PRESSURE BUILDS IN
BEHIND THE DEPARTING STORM THURSDAY NIGHT THROUGH AT LEAST FRIDAY.
WILL KEEP THIS PERIOD DRY. MODELS DO SHOW FALLING HEIGHTS AND
COOLING OF TEMPERATURES ALOFT...HOWEVER...COLD ADVECTION AT THE
SURFACE WILL PROBABLY BE TEMPERED TO A DEGREE BY A DOWNSLOPING
WESTERLY FLOW. HIGHS THEREFORE ON FRIDAY EXPECTED TO BE AT OR
SLIGHTLY BELOW NORMAL.
SATURDAY IS A LOW CONFIDENCE FORECAST. H5 TROF AND SHORTWAVE
APPROACHES FROM THE WEST...WITH THE TIMING OF ITS PASSAGE DIFFERING
AMONG THE MODELS. BEST GUESS WOULD BE FOR IT TO PASS THROUGH LATE
DAY SATURDAY OR SATURDAY NIGHT. ECMWF/GFS/GEFS/GGEM ALL SHOW COASTAL
LOW DEVELOPMENT OFF THE SOUTHEAST COAST AND PASSING EAST OF THE
40/70 BENCHMARK. TIMING FOR WHEN THIS HAPPENS IS QUICKEST WITH THE
GFS...SLOWEST WITH ECMWF...AND GGEM SOMEWHERE IN THE MIDDLE.
WILL GO WITH THE IDEA THAT OUR BEST CHANCES OF PRECIP COME WITH THE
SHORTWAVE AND POSSIBLE UPPER JET DYNAMICS...BUT WITH THE RECENT
WESTERN TREND OF THE COASTAL...WILL HAVE TO KEEP AN EYE ON THIS.
WILL THEREFORE GO WITH CHC POPS ON SATURDAY AND SATURDAY NIGHT.
THERMAL PROFILES WOULD SUPPORT RAIN/SNOW MIX FOR SATURDAY...AND
TREND MORE TOWARDS SNOW SATURDAY NIGHT. HIGHS RANGING IN THE UPPER
30S TO LOW 40S ON SATURDAY AS FORECAST 925MB TEMPS DROP TO AROUND
-3C TO -4C BY DAY'S END.
RIDGING THEN RETURNS AT THE SURFACE SUNDAY AND MONDAY WITH A DRY
FORECAST AND SLOWLY MODERATING TEMPERATURES.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
GUSTS EXPECTED TO DIMINISH FOR THE MOST PART BY 08Z...BUT AN
OCCASIONAL GUST NOT OUT OF THE QUESTION THROUGH 10Z.
GUSTS REMATERIALIZE DURING THE AFTERNOON TUESDAY. DIRECTION MAY BE
A BIT MORE TO THE RIGHT OF THE FORECASTED DIRECTIONS DURING
STRONGEST GUSTS.
OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...
TUE NIGHT-WED...VFR
WED NIGHT-THU...SUB-VFR LIKELY WITH IFR PROBABLE. LLWS POSSIBLE AS
WELL.
THU NIGHT-FRI...GUSTY NW WINDS. VFR.
FRI NIGHT...VFR WITH DIMINISHING WINDS.
SAT...VFR LIKELY WITH SUB-VFR POSSIBLE.
&&
.MARINE...
WITH THE RAIN A LITTLE SLOWER TO MOVE OFFSHORE HAVE UPDATED THE
FORECAST TO DELAY ENDING TIME BY A FEW HOURS. OTHERWISE NO OTHER
UPDATES AT THIS TIME.
SCA CONTINUES FOR THE OCEAN WATERS. SEAS WILL REMAIN ABOVE 5 FT
AND THERE COULD BE A GUST OR TWO CLOSE TO 25 KT...BUT A BETTER
CHANCE FOR 25-KT GUSTS IN WESTERLY FLOW WILL COME TUE AFTERNOON
AND EVENING AFTER A WARM FRONT PASSES TO THE NORTH. THE EASTERN
SOUND/BAYS COULD SEE SOME 25-KT GUSTS TUE AFTERNOON AS WELL...BUT
DO NOT THINK THESE WILL BE WIDESPREAD ENOUGH IN TIME OR SPACE TO
WARRANT SCA.
CONDITIONS THEN REMAIN BELOW SCA LEVELS UNTIL LATE WED NIGHT AS A
STRENGTHENING LOW MOVES TOWARD THE LOWER GREAT LAKES. GALES ARE
LIKELY FOR THE OCEAN WATERS AND POSSIBLE ELSEWHERE LATE WED
NIGHT INTO THU...STILL TOO EARLY FOR A GALE WATCH.
SCA CONDITIONS SHOULD CONTINUE INTO THU NIGHT...REMAINING ONLY
OVER THE EASTERN OCEAN WATERS BY FRI MORNING. SCA CONDITIONS COULD
RETURN ON SAT WITH THE POTENTIAL OF A COASTAL STORM...CURRENTLY
FORECAST TO PASS WELL SOUTH/EAST OF THE WATERS.
&&
.HYDROLOGY...
DRY THROUGH EARLY WEDNESDAY.
STRONG LOW PRESSURE COULD BRING SIGNIFICANT QPF OF 1-2 INCHES WED
NIGHT INTO THU. STILL TOO EARLY TO SAY WHETHER ANOTHER COASTAL
LOW COULD BRING ANOTHER ROUND OF SIGNIFICANT QPF THIS WEEKEND.
&&
.TIDES/COASTAL FLOODING...
THE APPROACH OF A FULL MOON WILL KEEP ASTRONOMICAL TIDES HIGH
OVER THE NEXT SEVERAL DAYS. AN INCREASING SOUTHERLY FLOW
ASSOCIATED WITH LOW PRES PASSING TO THE WEST COULD CAUSE MINOR
COASTAL FLOODING...MAINLY IN THE SOUTH SHORE BACK BAYS OF LONG
ISLAND THU MORNING. THE STRONGEST WINDS LOOK TO OCCUR RIGHT
AROUND THE TIME OF HIGH TIDE...BUT DUE TO THE FAIRLY QUICK
PROGRESSION OF THE STORM...WINDS WILL SHIFT TO THE SW AND
DECREASE BY THE EVENING HIGH TIDE CYCLE. DEPARTURES OF 1-1.5 FT
ARE NEEDED TO REACH MINOR COASTAL FLOODING LEVELS IN THE
MORNING...AND 2-2.5 FT IN THE EVENING.
LATEST GFS STORM SURGE GUIDANCE SUGGESTS DEPARTURES 1-2 FT AND
WIDESPREAD MINOR COASTAL FLOODING WITH THE THU MORNING HIGH TIDE.
MODERATE FLOODING APPEARS UNLIKELY DUE THE SHORT DURATION OF THIS
EVENT...BUT WILL STILL KEEP A CLOSE EYE ON THE MORE VULNERABLE
SOUTH SHORE BACK BAY LOCATIONS OF NASSAU COUNTY.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ350-353-
355.
&&
$$
AVIATION...BS
