Issued by NWS Upton, NY
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000 FXUS61 KOKX 230137 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 837 PM EST SUN NOV 22 2009 .SYNOPSIS... AS STRONG HIGH PRESSURE REMAINS OVER NORTHERN NEW ENGLAND AND THE CANADIAN MARITIMES...WEAK LOW PRESSURE WILL HEAD NORTHEAST JUST OFF THE SOUTHEAST COAST TONIGHT THROUGH MONDAY...AND THEN PASS SOUTHEAST OF LONG ISLAND MONDAY NIGHT AND SOUTH OF NOVA SCOTIA ON TUESDAY. HIGH PRESSURE WILL BRIEFLY RETURN TUESDAY NIGHT INTO WEDNESDAY. ANOTHER LOW WILL IMPACT THE AREA DURING THE SECOND HALF OF THE WORK WEEK...WITH POSSIBLE IMPROVEMENT BY THE WEEKEND. && .NEAR TERM /THROUGH MONDAY/... TRICKY FORECAST TONIGHT RE SKY COVER AND POTENTIAL FOR SOME LIGHT RAIN OR DRIZZLE. PATCHES OF STRATOCU DEVELOPING. WITH EVENTUAL COOLING BENEATH A LOW LEVEL INVERSION THINK THESE CLOUDS WILL GAIN THE UPPER HAND...ESPECIALLY AFTER MIDNIGHT. FORECAST SOUNDINGS ALSO SHOW VEERING LOW LEVEL WIND PROFILES...INDICATIVE OF MODEST WARM AIR ADVECTION AND POTENTIAL FOR ENOUGH LIFT TO GENERATE SOME LIGHT RAIN OR DRIZZLE AFTER MIDNIGHT. E-NE WINDS STAYING UP TONIGHT SHOULD KEEP RADIATIONAL COOLING AT BAY...WITH MINS AOA 12Z MAV GUIDANCE...WITH MID/UPPER 30S WELL INLAND AND LOWER/MID 40S IN URBAN AND COASTAL SECTIONS. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... OPERATIONAL MODELS HAVE COME AROUND TO SOME AGREEMENT RE THE EVENTUAL TRACK OF WEAK LOW PRESSURE DEVELOPING ALONG THE SOUTHEAST COAST TONIGHT...AND MOVING SLOWLY UP THE COAST LATE TONIGHT THROUGH TUE. THE 12Z GFS/RGEM/ECMWF WERE ALL IN GENERAL AGREEMENT...WITH THE ECMWF JUST A TAD WEAKER/SLOWER...WHILE THE NAM WAS A BIT FARTHER WEST. DISCOUNTED GEFS AND SREF MEAN SOLUTIONS AS THEY APPEARED TOO SUPPRESSED...NOT GIVING ENOUGH CREDENCE TO REDEVELOPMENT OF THE LOW FARTHER NORTHEAST LATE MON NIGHT AS AN UPPER TROUGH SWINGS TOWARD THE MID ATLANTIC COAST. AS A RESULT SIDED WITH A SLIGHTLY SLOWER AND WEAKER GFS SOLUTION WHICH CLOSELY PARALLELS THE ECMWF...WITH INCREASING CHANCES FOR RAIN DURING MON ESPECIALLY IN THE AFTERNOON...THEN CATEGORICAL POP WITH PERIODS OF MODERATE RAIN MON NIGHT. FCST MODELS APPEAR TOO QUICK TO DRY THINGS OUT ON TUE...AND THINK ENOUGH LOW LEVEL MOISTURE AND LIFT VIA CYCLONIC FLOW...EVEN SOME MODEST OROGRAPHIC LIFT IN NORTHERLY FLOW ACROSS LONG ISLAND... WILL HANG BACK TO PRODUCE MORE LIGHT RAIN/DRIZZLE THROUGH TUE MORNING. SKY COVER AND TEMPS ARE PROBLEMATIC FOR TUE NIGHT AS HIGH PRESSURE BUILDS IN. SIDED WITH MORE CLOUD COVER AND MILDER TEMPS...BUT COULD JUST AS EASILY ENVISION CLEARING SKIES...WITH BOTH LOWER TEMPS AND SOME FOG VIA RADIATIONAL COOLING AND LINGERING GROUND MOISTURE. A MOSTLY SUNNY DAY IS ON TAP FOR WED BEFORE THE NEXT SYSTEM BEGINS TO ARRIVE WITH SOME LOW CHANCE POP LATE IN THE DAY OR DURING THE EARLY EVENING. FOR TEMPS...DURING THE PRECIP EVENT BLENDED 12Z MAV AND NAM 2M TEMPS TO YIELD TEMPS COOLER THAN GUIDANCE. SIDED WITH TEMPS WARMER THAN 12Z MAV GUIDANCE TUE NIGHT...BUT CONFIDENCE IS LOW AS ALLUDED TO ABOVE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... CLOSED LOW MOVES ACROSS THE GREAT LAKES REGION WEDNESDAY NIGHT AND THURSDAY AS SFC LOW TRACKS JUST AHEAD OF IT. IT APPEARS AS THOUGH UPSTREAM SHORTWAVE DIVES OUT OF CENTRAL CANADA...AND ROUNDS THE BASE OF THIS LOW. AS SUCH...AMPLIFICATION OF THIS LOW TAKES PLACE AS IT PLOWS TOWARD THE EAST COAST LATE IN THE WEEK. ONE WOULD EXPECT A SFC LOW TO DEVELOP OFF THE SOUTHEAST/MID ATLC STATES AND MOVE NORTHWARD TO A POSITION JUST OFF THE COAST. THIS LOW SHOULD BECOME PRIMARY LOW IN TIME...WITH DEEPENING OCCURRING OVER NEW ENGLAND BY SATURDAY. GGEM DOES NOT OFFER THIS SCENARIO...WITH NOT MUCH COASTAL DEVELOPMENT EVIDENT. AS SUCH...GLOBAL MODELS OFFER SOME DIFFERENCES WITH HANDLING OF THIS COMPLEX SYSTEM THAT WILL IMPACT THE NORTHEAST THROUGH MUCH OF THIS TIME FRAME. EXACT DETAILS STILL HAZY...AND EC/HPC FOLLOWED THIS TIME FRAME. WOULD EXPECT AN INCREASE IN POPS WED NIGHT AND THURSDAY...ALTHOUGH WIDESPREAD QPF NOT ANTICIPATED QUITE YET. RAIN CHANCES WOULD CONTINUE FRIDAY...WITH POSSIBLE IMPROVEMENT BY THE WEEKEND AS DEEPER NORTHWEST FLOW TAKES HOLD. COULD BE WINDY THOUGH BEHIND THIS SYSTEM AS THE SFC LOW PASSES NORTH AND UPPER LOW MOVES EAST. LINGERING INSTABILITY POPS WARRANTED INTO SAT...WITH DRYING THEREAFTER. AS FOR ANY MIXED PRECIP...IT WILL BE COLD ALOFT BY THE WEEKEND (FRI NIGHT AND SAT) AS UPPER COLD POOL MOVES OVERHEAD. ANY SNOW MENTION WILL DEPEND ON BOUNDARY LAYER TEMPS IN DATABASE THIS TIME FRAME. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... PATCHY MVFR STRATUS DEVELOPING. THESE MVFR CIGS EXPECTED TO REDEVELOP AND BECOME MORE WIDESPREAD AS THE NIGHT PROGRESSES. WIND DIRECTIONS GENERALLY EASTERLY...BUT SPEEDS MAY BE LIGHTER THAN FORECAST THIS EVENING. PERIODS OF LIFR POSSIBLY...ALTHO NOT HIGH ENOUGH CONFIDENCE TO INCLUDE IN TAFS. BEST CHANCE AFTER 21Z MONDAY. OUTLOOK 00Z TUESDAY THROUGH FRIDAY... TUESDAY...SUB-VFR...PDS OF IFR LIKELY. GUSTY E-NE WINDS. TUESDAY NIGHT...BECOMING VFR. WEDNESDAY...VFR. WEDNESDAY NIGHT-THURSDAY...SUB-VFR POSSIBLE. FRIDAY...SUB VFR POSSIBLE EARLY WITH GUSTY NW WINDS IN THE PM. && .MARINE... SCA UP FOR ALL OCEAN ZONES...WITH WINDS AND SEAS RAMPING UP AS PRES GRADIENT CONTINUES TO TIGHTEN UP BETWEEN HIGH PRESSURE TO THE NORTH...AND A DEVELOPING COASTAL LOW. QUIET CONDITIONS ON THE SOUND/HARBOR/BAYS WILL BE SHORT LIVED. E-NE FLOW WITH SCA CONDITIONS LIKELY TO CONTINUE ON ALL WATERS THROUGH MON NIGHT...WITH MAX OCEAN SEAS 9 OR 10 FT...JUST SHY OF WAVEWATCH VALUES. GALES UNLIKELY TO OCCUR...BUT IT COULD BE A CLOSE CALL ON THE FAR EASTERN OCEAN WATERS LATE MON NIGHT OR EARLY TUE MORNING AS THE COASTAL LOW PASSES BY. PROBABILITY OF GALES LESS THAN 50 PERCENT ATTM...SO DID NOT ISSUE A WATCH. SCA CONDITIONS SHOULD CONTINUE ON THE OCEAN AT LEAST THROUGH THE DAY ON TUE AND POSSIBLY INTO TUE NIGHT...WITH WINDS DIMINISHING BUT SEAS SLOW TO SUBSIDE AFTER THE LOW PASSES. SCA CONDITIONS MAY ALSO CONTINUE AT LEAST INTO TUE MORNING ON THE EASTERN SOUND/BAYS. WINDS BACK TO THE SOUTHEAST WED NIGHT...AND EAST THURSDAY AS INLAND LOW/FRONT NEARS. IF COASTAL LOW DEVELOPS OFF SE/MID ATLC COAST LATER THURSDAY AND FRIDAY...WOULD SEE AN INCREASE IN WINDS AS THEY BACK TO THE NORTH. WINDS BACK FURTHER TO THE WEST/NW FRIDAY AND SATURDAY AS THE LOW DEEPENS AND TRACKS JUST TO THE NORTH. SPEEDS WILL PICK UP QUITE A BIT. A GRADUAL INCREASE IN SEAS EXPECTED THURSDAY AND FRIDAY AS COASTAL LOW IMPACTS THE AREA WATERS. WAVE WATCH III OUTPUT SEEMS REASONABLE. EASTERN WATERS ON FRIDAY WILL OBSERVE HIGHEST SEAS DUE TO STRONG WEST FETCH. && .HYDROLOGY... QPF FOR THE UPCOMING EVENT CALLS FOR 1/2 INCH MOST OF THE AREA...AND 1/2 TO 3/4 INCH ACROSS SOUTHEAST CT AND EASTER LONG ISLAND. ADDITIONAL PRECIPITATION IS POSSIBLE THU AND FRI. NO HYDROLOGIC PROBLEMS ARE ANTICIPATED. && .TIDES/COASTAL FLOODING... 36 TO 48 HOUR PERIOD OF E-NE WINDS EXPECTED TO RESULT IN WATER LEVELS AROUND 2 FT ABOVE NORMAL. THE CURRENT TIDE CYCLES ARE INCREASING...BUT ARE NOT AT ASTRONOMICAL HIGHS UNTIL NEXT WEEK. BASED ON CURRENT LEVELS...2.5 TO 3 FT IS NEEDED FOR MINOR FLOODING FOR BOTH MONDAY AFTERNOON AND TUESDAY AFTERNOON HIGH TIDE CYCLES. THEREFORE NO PRODUCTS WILL BE ISSUED AT THIS TIME. THE SITUATION WILL BE MONITORED CLOSELY. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST TUESDAY FOR ANZ330-335-338-340-345. SMALL CRAFT ADVISORY UNTIL 6 PM EST TUESDAY FOR ANZ350-353-355. && $$ SYNOPSIS...BG NEAR TERM...BG/PW SHORT TERM...BG LONG TERM...PW AVIATION...BS/PW MARINE...BG/PW HYDROLOGY...BG TIDES/COASTAL FLOODING...BS
