FXUS61 KOKX 010007
AFDOKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
707 PM EST MON NOV 30 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 TUESDAY 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 TUESDAY 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 /00Z TUESDAY THROUGH SATURDAY/...
W-NW WINDS BEGINNING TO GUST ACROSS KNYC TERMINALS TO 20 KT. WILL
LOOK FOR W-NW WINDS AT AROUND 15 KT WITH GUSTS TO 20-25 KT FOR THE
REST OF THE EVENING. THOSE WINDS WILL GRADUALLY MAKE THEIR WAY
TOWARDS EASTERN TERMINALS OVER THE NEXT HOUR OR SO.
FOR KNYC TERMINALS...WINDS WILL GENERALLY HOVER AROUND THE 310
DEGREE MARK...RANGING FROM 320 DEGREES TO 300 DEGREES UNTIL
SETTLING ON 300 DEGREES BY 09Z.
CONDITIONS WILL RAPIDLY IMPROVE FROM MVFR TO VFR FROM WEST TO EAST
THROUGH ABOUT 03-04Z AS WELL. VFR CIGS/VSBYS EXPECTED FOR THE REST
OF THE TAF PERIOD.
WINDS DIMINISH LATE TONIGHT AND TOWARD TUE MORNING (09-10Z). THERE
WILL BE A BREAK IN THE WINDS...AS NW WINDS WILL BE AROUND 10 KT
THROUGH LATE TUE MORNING. WINDS BECOME MORE WESTERLY BY
AFTERNOON...INCREASING TO 10-15 KT WITH GUSTS UP TO 20 KT.
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...
A COLD FRONT CROSSING THE AREA HAS BROUGHT WIDESPREAD 0.10-0.25
AND ISOLATED 0.25-0.50 INCH RAINFALL THUS FAR. AN ADDITIONAL
0.10-0.25 INCH IS POSSIBLE FOR NYC...LONG ISLAND AND MUCH OF
SOUTHERN CT INTO THIS EVENING.
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 TUESDAY NIGHT FOR
ANZ350-353-355.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...MPS
MARINE...
HYDROLOGY...
TIDES/COASTAL FLOODING...
