Issued by NWS Upton, NY
Versions: 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --000 FXUS61 KOKX 231805 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 105 PM EST MON NOV 23 2009 .SYNOPSIS... LOW PRESSURE PASSING WELL SOUTH AND EAST OF LONG ISLAND TODAY AND TONIGHT WILL BRING A MOIST NORTHEASTERLY FLOW TO THE TRI-STATE AREA. THE LOW WILL GRADUALLY MOVE EAST OF CAPE COD ON TUESDAY AND ALLOW HIGH PRESSURE TO BUILD IN TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE TRACKS FROM THE GREAT LAKES INTO NEW ENGLAND ON THURSDAY INTO FRIDAY RESULTING IN UNSETTLED WEATHER. COLDER AND BREEZY WEATHER MOVES IN FOR THE WEEKEND IN THE WAKE OF THE SYSTEM. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN CHANGES TO THE FORECAST WERE TO DECREASE POPS FOR WESTERN SECTIONS AS NEW MODEL GUIDANCE AS WELL AS CURRENT RADAR SUPPORTS ONLY SPOTTY LIGHT RAIN OR DRIZZLE. INCREASED POPS TO THE EAST AS THE SHOWERS OVER THE TWIN FORKS AND SOUTHEASTERN CONNECTICUT HAVE BECOME BETTER ORGANIZED...ALSO SEE SOME THETA E ADVECTION AT H850 IN THE NAM AND GFS...INDICATING ADVECTION OF MOISTURE. WITH THE RIGHT ENTRANCE OF THE UPPER JET REMAINING OFFSHORE...DO NOT EXPECT FORCING TO BE ORGANIZED ENOUGH TO SUPPORT ANY SIGNIFICANT RAINFALL. TEMPS DO NOT MOVE MUCH TODAY DO TO THE LACK ON HEATING AND THE MODERATELY BREEZY CONDITIONS OFF THE ATLANTIC. BOTTOM LINE - A RAW NOVEMBER DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... WEAK LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST AND TRACKS NORTHEAST TO A POSITION EAST OF CAPE COD BY LATE TUESDAY. THIS IS BEING DRIVEN BY SHORT WAVE ENERGY COMING OUT OF THE TENNESSEE VALLEY THIS MORNING AS SEEN IN THE WATER VAPOR IMAGERY. THIS SHORTWAVE MOVES THOUGH THE LONG WAVE RIDGE ON THE EAST COAST AND CLEARS OUT THE OLD CUT OFFS THAT HAVE BEEN SITTING AROUND (CURRENTLY OVER WESTERN CT AND EASTERN KY). AS A RESULT OF THE WEAK UPPER FORCING, DO NOT BELIEVE THE OPERATIONAL GFS DEVELOPMENT OF A 1006 HPA ON TUESDAY EAST OF CAPE COD. PREFER THE WEAKER (OLD) ECMWF RUN. THE LOCAL IMPORTANCE OF THIS CHOICE IS TUESDAY`S CLOUDS AND RESULTING TEMPS. THE WEAKER SOLUTION KEEPS WINDS MORE EASTERLY ON TUESDAY RESULTING IN ANOTHER CLOUDY DAY WITH COOL TEMPS AND OCCASIONAL LIGHT PCPN - AT LEAST IN THE MORNING. THE ABOVE ALSO IS CONSISTENT WITH THE PREVIOUS FORECAST. WHICH, WITH UNCERTAINTY FOR TUESDAY BEING HIGH IN TERMS OF CLOUD COVER AND TEMPS, IS BEST TO STAY WITH THAT FORECAST AND NOT FLIP/FLOP. TEMPS RANGE IS SMALL THE NEXT 48 HOURS DUE TO CLOUDINESS AND PERSISTENT EASTERLY FLOW. WEDNESDAY LOOKS GOOD AS HIGH PRESSURE BUILDS IN. TEMPS WERE RAISED SLIGHTLY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...-- Changed Discussion --UNSETTLED DESCRIBES THE PERIOD. CLOSED LOW MOVES FROM CHICAGO THURSDAY AM TO NEAR LOCAL AREA BY SATURDAY MORNING AS IT DEEPENS. LATEST GFS (00Z)IS VERY SIMILAR TO THE OLD (12Z) ECMWF WITH THIS PART OF THE FORECAST. NCEP GLOBAL ENSEMBLE FORECAST SYSTEM SHOW SURPRISINGLY LITTLE SPREAD WITH THIS SYSTEM. THUS, THE LONG TERM APPEARS TO HAVE MORE FORECAST CONFIDENCE THAN THE SHORT TERM. AT THE SURFACE, WEAK LOW PRESSURE NEAR MICHIGAN ON THURSDAY REDEVELOPS ON THE TRIPLE POINT ON FRIDAY AM OVER THE LOCAL AREA AND THEN DEEPS RAPIDLY OVER NEW ENGLAND. IN TERMS OF SENSIBLE WEATHER...DIFFLUENT SOUTHWESTERLY FLOW ALOFT AND ON-SHORE SOUTHEASTERLY SURFACE FLOW MEAN CLOUDS WITH AT LEAST A CHANCE OF LIGHT RAIN FOR THANKSGIVING. THE RAPID DEVELOPMENT OF THE SURFACE LOW EARLY FRIDAY (WITH A FEW HUNDRED JOULES OF ELEVATED CAPE ON THE GFS SOUNDINGS) SUPPORTS THE POSSIBILITY OF MORE RARE NOVEMBER THUNDERSTORMS. THIS ALONG WITH HEAVIER RAIN AND STRONG EASTERLY WINDS MEANS A RATHER UNPLEASANT TIME FOR EARLY MORNING SHOPPERS. ON SATURDAY...WHILE UPPER LOW TRACKS OVER THE REGION, THE DEEPER (COLDER) GFS PROFILES KEEP ANY MIXED PCPN INLAND. WINDY TOO ON THE BACKSIDE OF THE DEEP LOW. BASED ON GFS PROFILES...THERE SOME POTENTIAL FOR WIND ADVISORY FOR SATURDAY.-- End Changed Discussion --&& .AVIATION /18Z MONDAY THROUGH SATURDAY/...-- Changed Discussion --WIDESPREAD MVFR CEILINGS THE REMAINDER OF THIS AFT. CEILINGS TO DROP BELOW 2 KFT BY 20Z. ANY LIGHT RAIN/DRIZZLE WILL BE SPOTTY WITH BRIEF EPISODES OF MVFR VSBYS...BUT PRIMARILY AFTER 00Z. DIFFICULT FORECAST TOWARD 00Z AS CEILINGS APPROACH IFR. CEILINGS WILL BE RIGHT AROUND THE UPPER END OF THE IFR CATEGORY OR LOW END OF THE MVFR CATEGORY. WINDS TO REMAIN FROM THE NORTHEAST...020 TO 050...THROUGH THE PERIOD WITH SPEEDS 10 TO 15 KT. GUSTS UP TO 20 KT NYC TERMINALS THROUGH 20Z. TAF COMMENTS (FORECASTER INSIGHT ON TIMING, CONFIDENCE, TRENDS AND GROUND OPS) KEWR...AFTER 00Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. GUSTS UP TO 20 KT POSSIBLE THROUGH 20Z. KEWR HOURLY WIND FORECAST ALL WIND DIRECTIONS ARE TRUE...ADD 13 DEGREES FOR MAGNETIC 23/16Z 03012KT 23/17Z 03012KT 23/18Z 03012KT 23/19Z 03012KT 23/20Z 03012KT 23/21Z 03012KT 23/22Z 03012KT 23/23Z 03011KT 24/00Z 03010KT 24/01Z 03010KT 24/02Z 03010KT 24/03Z 03010KT KJFK...AFTER 23Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. GUSTS UP TO 20 KT POSSIBLE THROUGH 20Z. KLGA...AFTER 00Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. GUSTS UP TO 20 KT POSSIBLE THROUGH 20Z. KTEB...AFTER 00Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. KHPN...AFTER 23Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. KSWF...AFTER 00Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. KISP...AFTER 00Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. KBDR...AFTER 00Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. KGON...AFTER 23Z...CEILINGS WILL VARY BETWEEN IFR AND MVFR...AMENDMENTS LIKELY. OUTLOOK 18Z TUESDAY THROUGH FRIDAY... TUESDAY AFT-WED...VFR. WEDNESDAY NIGHT THROUGH THURSDAY...SUB VFR POSSIBLE IN LIGHT RAIN. FRIDAY...SUB VFR POSSIBLE IN SHOWERS. SNOW POSSIBLY MIXING IN NORTH AND WEST OF THE NYC TERMINALS AT NIGHT. SATURDAY...VFR CEILINGS IN STRONG COLD ADVECTION/CYCLONIC FLOW.-- End Changed Discussion --&& .MARINE... SCA UP FOR ALL WATERS TODAY WITH THE PRESSURE GRADIENT CONTINUING TO TIGHTEN BETWEEN HIGH PRES OVER THE CANADIAN MARITIMES AND LOW PRES WORKING NE ALONG THE CAROLINA COAST. PRESSURE GRADIENT WILL REMAIN TIGHT THROUGH TUESDAY. THE PERSISTENT STRONG NE FLOW WILL BUILD SEAS TO 6-11 FT BY TONIGHT (HIGHEST SE PORTION OF ANZ-350 LOWEST WESTERN PORTION OF ANZ-355). COULD SEE SOME 5-6 FT WAVES NEAR THE MOUTH OF LONG ISLAND SOUND LATE TONIGHT/TUESDAY MORNING AS WELL. AS LOW PULLS TO THE ENE TUESDAY WINDS BACK TO THE N AND DIMINISH SLIGHTLY. N WINDS CONTINUE TO DIMINISH TUESDAY NIGHT AS PRESSURE GRADIENT CONTINUE TO RELAX...AND EXPECT THE SOUND/HARBOR/BAYS TO FALL BELOW SCA CRITERIA BY MIDNIGHT...BUT SEAS ON THE OCEAN ZONES WILL STAY AT/ABOVE CRITERIA THROUGH ALL THE NIGHT. HIGH PRESSURE BUILDING IN WEDNESDAY/WEDNESDAY NIGHT SHOULD PROVIDE A 24 HOUR OR SO PERIOD WITH SUB-SCA CONDITIONS. THIS LULL COMES TO AN END LATE THURSDAY AS WINDS INCREASE OUT OF THE E AHEAD OF ANOTHER COASTAL STORM...THIS ONE LIKELY MUCH STRONGER THAN THE ONE THAT IMPACTED THE AREA EARLIER IN THE WEEK. FOR NOW CAPPING THINGS AT SMALL CRAFT LEVELS DUE TO SOME UNCERTAINTY IN THE LOW/S TRACK/STRENGTH BUT WOULD NOT BE SURPRISED IF AT LEAST GALE FORCE GUSTS IMPACTED ALL WATERS THU NIGHT INTO FRIDAY. && .HYDROLOGY... LIGHT PCPN STARTING ACROSS EASTERN LI/SE CT THIS MORNING...THEN SPREADING WEST BY AFT. QPF IS GENERALLY A QUARTER INCH OR LESS. A MORE SIGNIFICANT QUANTITATIVE PRECIPITATION EVENT IS POSSIBLE THURSDAY NIGHT INTO EARLY FRIDAY WITH OVER AND INCH ON AVERAGE. AT THIS TIME...NO SIGNIFICANT HYDROLOGIC PROBLEMS ARE ANTICIPATED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST TUESDAY FOR ANZ330-335-338- 340-345-350-353-355. && $$ SYNOPSIS...JST NEAR TERM...BG SHORT TERM...JST LONG TERM...JST AVIATION...DW MARINE...BG HYDROLOGY...JST
