Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 302024 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 424 PM EDT MON MAR 30 2015 .SYNOPSIS...
-- Changed Discussion --
A COLD FRONT WILL PASS LATE TODAY...FOLLOWED BY A QUICK MOVING LOW PASSING TO THE SOUTH ON TUESDAY. HIGH PRESSURE WILL BUILD ACROSS THE AREA ON WEDNESDAY AHEAD OF A FRONTAL SYSTEM MOVING INTO THE PLAINS. THE FRONTAL SYSTEM WILL THEN PROGRESS SLOWLY ACROSS THE AREA FROM LATE THURSDAY INTO EARLY SATURDAY. HIGH PRESSURE WILL RETURN LATER THIS WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
COLD FRONT HAD PASSED NYC METRO AS OF 20Z AND WAS MOVING INTO SRN CT AND LONG ISLAND. A FEW SHOWERS WILL ACCOMPANY/FOLLOW FROPA...MAINLY ACROSS SRN CT WHERE HAVE CARRIED SCT POP UNTIL ABOUT 23Z-00Z. THEN EXPECT SKIES TO BECOME MOSTLY CLEAR...WITH A BRISK W TO WNW FLOW DIMINISHING OVERNIGHT. WITH CLEAR SKIES AND DIMINISHING WINDS SIDED WITH THE COLDER GUIDANCE...WITH UPPER 20S INLAND AND IN THE LONG ISLAND PINE BARRENS...LOWER 30S MOST ELSEWHERE...AND MID/UPPER 30S INVOF NYC.
-- End Changed Discussion --
&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
-- Changed Discussion --
ALBERTA CLIPPER LOW NOW MOVING SE ACROSS THE NRN PLAINS WILL CONTINUE SE...REACHING THE NRN MID ATLANTIC BY TUE AFTERNOON. EXPECT TUE MORNING TO BE DRY WITH INCREASING CLOUDS...THEN PRECIP SHOULD OVERSPREAD THE AREA IN THE AFTERNOON. HAVE LIKELY/CAT POP FOR NEARLY THE ENTIRE CWA...EXCEPT FOR SOUTHERN CT AS THERE IS SOME UNCERTAINTY AS TO HOW FAR NORTH THE ASSOCIATED PRECIP SHIELD WILL EXTEND SINCE NWP GUIDANCE SHOWS BEST WAA AND H5 FORCING PASSING MAINLY OVER NYC METRO/LONG ISLAND AND POINTS SOUTH. PRECIP DURING THE DAYLIGHT HRS SHOULD BE MAINLY RAIN FOR NYC METRO AND LONG ISLAND...BUT INLAND THERE IS SOME UNCERTAINTY AS TO PRECIP TYPE. ATTM EXPECT AN ELEVATION-DEPENDENT SNOWFALL...WITH A COLD RAIN OR A RAIN/SNOW MIX IN THE LOWER ELEVATIONS...AND MOSTLY SNOW IN THE HIGHEST ELEVATIONS. P-TYPE SHOULD TREND MORE TOWARD SNOW THROUGHOUT BEFORE ENDING AS THE BOUNDARY LAYER COOLS VIA WET-BULB COOLING AND AN INCREASING COLDER NORTHERLY FLOW. ATTM EXPECT LITTLE TO NO ACCUMULATION IN NYC METRO...NO MORE THAN A COATING MOST ELSEWHERE AND UP TO AN INCH IN THE HIGHEST ELEVATIONS. THE WORST-CASE SCENARIO WOULD BE A COATING OF ACCUMULATION IN NYC...UP TO AN INCH MOST ELSEWHERE...AND 1-2 INCHES IN THE HIGHER ELEVATIONS.
-- End Changed Discussion --
&& .LONG TERM /WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
A PROGRESSIVE...YET SOMEWHAT AMPLIFIED UPPER FLOW ACROSS THE LOWER 48...WILL BE FEATURED DURING THE PERIOD. THIS WILL RESULT IN SEVERAL SWINGS IN THE TEMP REGIME AS WE GO FROM BELOW NORMAL AT THE START OF THE PERIOD...TO ABOVE NORMAL AHEAD OF AN APPROACHING FRONTAL SYSTEM AT THE END OF THE WEEK...FOLLOWED BY YET ANOTHER SHOT OF UNSEASONABLY COLD AIR AT THE END OF NEXT WEEKEND. THERE ARE ALSO SOME TIMING ISSUES...IN PARTICULAR WITH THE FRONTAL SYSTEM AT THE END OF THE WEEK. THE GFS IS MORE AGGRESSIVE WITH A RAINFALL WITH A FRONTAL WAVE...WHILE THE ECMWF HAS THAT WAVE DISPLACED FARTHER NORTH AND WEST. EVEN SO...BOTH THE 12Z GFS AND ECMWF DRY CONDITIONS OUT BEHIND THE COLD FRONTAL PASSAGE ON SAT. THE DIFFERENCES ARISE DUE TO THE TIMING OF THE PAC SHORTWAVE ENERGY. THE SPECIFICS OF SUCH CAN NOT BE WORKED OUT THIS EARLY IN THE FORECAST PROCESS. PREFERENCE WAS TO TAKE A MIDDLE GROUND APPROACH WITH THE TIMING OF THE LATE WEEK SYSTEM.
-- End Changed Discussion --
&& .AVIATION /20Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
A COLD FRONT CONTINUES TO MOVE ACROSS THE TERMINALS THROUGH EARLY THIS EVENING. WEAK HIGH PRES BUILDS OVER THE AREA TONIGHT...AND THEN WEAK LOW PRES IMPACTS THE TERMINALS LATE TUESDAY AND TUESDAY NIGHT. WINDS HAVE SHIFTED TO THE W/NW ACROSS THE WESTERN TERMINALS AND WILL SHIFT FROM THE W-SW TO THE W/NW OVER EASTERN TERMINALS BY EARLY THIS EVENING AS THE COLD FRONT WORKS ITS WAY EAST. WIND SPEEDS WILL BE AROUND 15 KT WITH 25 KT GUSTS AFTER ITS PASSAGE...AND THEN GUSTS END AND WINDS DIMINISH TO 8-12 KT THIS EVENING. AFTER MIDNIGHT...WEST WINDS WILL AVERAGE 5-8 KT...AND THEN INCREASE BY A FEW KT LATE TUESDAY MORNING. BKN DECK AROUND 4000 FT LATE THIS AFTERNOON WILL SCATTER OUT THIS EVENING...AND THEN SKC CONDS EXPECTED AFTER MIDNIGHT TONIGHT. MID- DECK INCREASES TUESDAY MORNING AS LOW PRES APPROACHES FROM THE WEST. VFR THROUGH 18Z TUESDAY. FOR THE 30-HR SITES...KJFK/KEWR/KSWF...MVFR CONDS IN RAIN FOR KJFK/KEWR AND -SN FOR KSWF AFT 21Z TUESDAY. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: WINDS 270-290 MAG WITH PEAK GUSTS 25-27 KT THROUGH 23Z. KLGA FCSTER COMMENTS: WINDS 280-300 MAG WITH PEAK GUSTS 25 TO 28 KT THROUGH 23Z. KEWR FCSTER COMMENTS: WINDS 260-280 MAG WITH PEAK GUSTS AROUND 25 KT THROUGH 23Z. KTEB FCSTER COMMENTS: W-NW WINDS WITH PEAK GUSTS UP TO 25 KT THROUGH 23Z. KHPN FCSTER COMMENTS: W-NW WINDS WITH PEAK GUSTS UP TO 25 KT THROUGH 23Z. KISP FCSTER COMMENTS: W-NW WINDS WITH PEAK GUSTS AROUND 25 KT THROUGH 00Z. .OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY... .TUESDAY AFTERNOON...MVFR IN DEVELOPING RAIN/SNOW. .TUESDAY NIGHT...CONDS IMPROVING TO VFR BY MIDNIGHT TUESDAY NIGHT. .WEDNESDAY-THURSDAY...VFR. .THURSDAY NIGHT-FRIDAY...MVFR IN RAIN SHOWERS. .SATURDAY...MVFR IN RAIN SHOWERS POSSIBLE.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
SCA IN EFFECT ATTM FOR NY HARBOR AND THE OCEAN WATERS. COLD FROPA HAS BROUGHT W WINDS GUSTING TO 25-30 KT TO THE HARBOR THAT SHOULD PERSIST UNTIL 8 PM OR SO. SEAS ON THE OCEAN ARE 4-6 FT ATTM AND MAY INCREASE ANOTHER FT OUT EAST AS THE FLOW SHIFTS FROM SW TO W AFTER FROPA TONIGHT. GUSTS OUT EAST AFTER FROPA SHOULD REACH SCA LEVELS AS WELL...BUT DID NOT ISSUE SCA FOR THE WRN SOUND OR THE SOUTH SHORE BAYS AS GUSTS TO 25 KT LOOK TO BE ONLY BRIEF/OCNL IN NATURE EARLY THIS EVENING. SCA CONDS COULD LAST ON THE OCEAN THROUGH TUE NIGHT...AND ALSO RETURN TO THE ERN WATERS TUE NIGHT...AS LOW PRESSURE PASSES TO THE S AND NORTHERLY FLOW INCREASES IN ITS WAKE. THEN EXPECT SUB-SMALL CRAFT LEVEL CONDITIONS WED THROUGH THU AS A WEAK PRESSURE GRADIENT REMAINS OVER THE REGION. WIND GUSTS AND WAVES INCREASE TO SMALL CRAFT LEVELS AHEAD OF THE NEXT SYSTEM APPROACHING THE OCEAN WATERS THURSDAY NIGHT INTO SATURDAY.
-- End Changed Discussion --
&& .HYDROLOGY...
-- Changed Discussion --
QPF OF 1/10 TO 1/4 INCH EXPECTED TUE AFTERNOON AND EVENING. THERE IS THE POTENTIAL FOR WIDESPREAD RAINFALL AT THE END OF THE WEEK WITH A FRONTAL WAVE ALONG A SLOW MOVING FRONTAL SYSTEM. RIVERS AND STREAMS ARE EXPECTED TO REMAIN BELOW BANK FULL...BUT INCREASED RIVER/STREAM FLOW ACROSS THE LOWER HUDSON VALLEY AND SOUTHERN CONNECTICUT WILL CONTINUE ICE BREAKUP AND MOVEMENT INTO THIS WEEKEND. ISOLATED ICE JAMS ARE POSSIBLE...WHICH IF THEY OCCUR...COULD RESULT IN LOCALIZED FLOODING. SINCE ICE JAM FLOODING IS UNPREDICTABLE AND SUDDEN...INTERESTS ALONG ICE COVERED RIVERS SHOULD MONITOR NWS FORECASTS FOR THE LATEST INFORMATION. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE.
-- End Changed Discussion --
&& .OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ338. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO NOON EDT TUESDAY FOR ANZ330-340. SMALL CRAFT ADVISORY UNTIL NOON EDT TUESDAY FOR ANZ350-353-355.
-- End Changed Discussion --
&& $$ SYNOPSIS...GOODMAN/DW NEAR TERM...GOODMAN SHORT TERM...GOODMAN LONG TERM...DW AVIATION...MPS MARINE...GOODMAN/DW HYDROLOGY...GOODMAN/DW

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.