Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 211132 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 732 AM EDT MON APR 21 2014 .SYNOPSIS... HIGH PRESSURE RETREATS TO THE EAST THROUGH TONIGHT. A COLD FRONT APPROACHES FROM THE WEST TUESDAY MORNING...THEN CROSSES THE TRI- STATE TUESDAY AFTERNOON AND EVENING. HIGH PRESSURE THEN BUILDS INTO THE REGION FOR THE MIDDLE TO THE END OF THE WORK WEEK. LOW PRESSURE AND A FRONTAL SYSTEM THEN IMPACTS THE REGION AT THE END OF THE WEEK AND INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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SOME PATCHY STRATUS DEVELOPED OVER SE CT AND INTO THE NORTH FORK OF LONG ISLAND. THAT SHOULD DISSIPATE OVER THE NEXT COUPLE OF HOURS AS TEMPS CONTINUE TO WARM INTO THE 40S. OTHERWISE...WILL ADJUST HOURLY GRIDS BASED ON LATEST SFC OBS AND IR SAT IMG. NORTHERN STREAM RIDGE OVER SW ONTARIO/UPPER MIDWEST BUILDS OVER THE AREA TODAY. ASSOCIATED SUBSIDENCE WILL KEEP THINGS DRY WITH MINIMAL CLOUD COVER...OTHER THAN A FEW PASSING HIGH CLOUDS FROM TIME TO TIME. FOR HIGHS TODAY USED A BLEND OF MIXING DOWN FROM 950-925 HPA PER BUFKIT SOUNDINGS...WITH NAM 2-METER TEMPERATURES AND A BLEND OF MAV/MET GUIDANCE. LIMITED MIXING DUE TO SUBSIDENCE...PLUS ONSHORE FLOW WILL KEEP TEMPERATURES COOLER THAN 850 TEMPERATURES AROUND 10C WOULD USUALLY IMPLY...WITH MID-UPPER 50S AT THE IMMEDIATE COAST...AND GENERALLY LOW-MID 60S ELSEWHERE. HOWEVER...SHOULD SEE SOME SCATTERED READINGS IN THE UPPER 60S ACROSS PORTIONS OF NE NJ AND THE LOWER HUDSON VALLEY.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... RIDGE AXIS SLIDES TO THE EAST TONIGHT...ALLOWING FOR HIGH THEN MID CLOUDS TO BUILD IN OVERNIGHT FROM W TO E. FOR LOWS USED A BLEND OF MAV AND MET GUIDANCE WITH VALUES FORECAST A FEW DEGREES ABOVE NORMAL. 700-500 HPA LONGWAVE TROUGH APPROACHES TUESDAY...ALONG WITH SURFACE-850 HPA COLD FRONT. GFS APPEARS TO BE PROGRESSIVE OUTLIER WITH HOW FAST FRONT AND PRECIPITATION MOVES THROUGH...SO USED A NON-GFS BLEND FOR THE FORECAST ON TUESDAY. TUESDAY MORNING SHOULD BE DRY THROUGH OUT...WITH MAINLY A SCT-BKN MID DECK ACROSS THE REGION. SHOWERS SHOULD BEGIN TO WORK INTO WESTERN ZONES EARLY-MID AFTERNOON...THEN ACROSS THE REMAINDER OF THE AREA LATE IN THE AFTERNOON. APPEARS THERE COULD BE ENOUGH INSTABILITY OVER MOST OF NE NJ AND MAINLY W PORTIONS OF THE LOWER HUDSON VALLEY - NAM HAS A FEW HUNDRED J/KG OF CAPE BY LATE AFTERNOON...AND BOTH NAM AND GFS BUFKIT SOUNDINGS HAVE TOTAL TOTALS AT KSWF GET TO 51 - SO HAVE SLIGHT CHANCE OF THUNDER IN THOSE AREAS IN THE AFTERNOON AS WELL. MARINE INFLUENCE FARTHER EAST SHOULD PRECLUDE ANY THUNDER FROM FORMING FARTHER EAST...AND SHOULD PROMOTE THE RAPID WEAKENING OF ANY STRONGER CONVECTION WHICH WERE TO MOVE IN FROM THE W. NOTING WET BULB ZERO HEIGHTS AROUND 7000 FT...LEVEL OF FREE CONVECTION BELOW 1000 M...AND 500 HPA TEMPERATURES AROUND -16 TO -18C WOULD NOT BE SURPRISED AT SOME SMALL TO POSSIBLY MARGINALLY SEVERE HAIL WITH THE STRONGEST CONVECTION. FOR HIGHS TUESDAY USED A BLEND OF MAV/MET GUIDANCE...NAM 2-METER TEMPERATURES AND MIXING DOWN FROM 975-925 HPA PER BUFKIT SOUNDINGS. HIGHS IN COASTAL AREAS SHOULD BE NEAR TO SLIGHTLY ABOVE NORMAL...AND INLAND SHOULD RUN AROUND 5 DEGREES ABOVE NORMAL...WITH A FEW SPOTS REACHING OR GETTING JUST ABOVE THE 70 DEGREE MARK. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... SOME DISCREPANCIES WITH THE MODELS TUESDAY NIGHT WITH THE PASSAGE OF THE FRONTAL SYSTEM. COLD FRONT SLIDES THROUGH THE REGION IN THE EVENING AND WILL BE CLEAR OF EASTERN ZONES BY DAYBREAK WEDNESDAY. GFS IS THE FASTEST OF THE MODELS AND HAS PRECIP ENDING PRETTY MUCH FROM 00-06Z...BUT THE ECMWF/NAM/SREF/CMC ARE A BIT SLOWER AND ENDS PRECIP A BUT LATER. EITHER WAY...WILL CARRY THE HIGHEST POPS EARLY...AND WILL TAPER DOWN TO CHANCE BY MIDNIGHT. WITH UPPER TROUGH AND STRONG SHORTWAVE FOLLOWING BEHIND THE FRONT...WILL KEEP SLIGHT CHANCE POPS IN THE FORECAST THROUGH WEDNESDAY MORNING. HIGH PRES BUILDS IN BEHIND THE DEPARTING FRONT. SKIES CLEAR OUT DURING THE DAY...AND THE PRES GRADIENT TIGHTENS...RESULTING IN A STRONG NW FLOW OF 20-30 MPH WITH THE POTENTIAL FOR GUSTS UP TO 40 MPH. WINDS DIMINISH WEDNESDAY EVENING AS THE GRADIENT RELAXES AS THE HIGH BUILDS EAST...AND THEN WILL BE NEARLY OVERHEAD ON THURSDAY. GUSTY CONDITIONS COULD DEVELOP AGAIN ACROSS EASTERN ZONES DURING THE DAY. THE HIGH DEPARTS THURSDAY NIGHT AS A FRONTAL SYSTEM APPROACHES FROM THE WEST. THAT SYSTEM WILL IMPACT THE REGION FOR THE END OF THE WEEK AND INTO THE WEEKEND. FOR NOW...WILL CARRY CHANCE POPS FROM MAINLY FRIDAY AFTERNOON THROUGH SATURDAY NIGHT. STRONG NW FLOW WILL USHER CAA INTO THE REGION FOR WEDNESDAY AND THURSDAY...AND HIGHS WILL BE IN THE UPPER 50S TO AROUND 60 BOTH DAYS. FOR THE END OF THE WEEK...TEMPS WARM BACK UP INTO THE LOW TO MID 60S. LOWS WILL BE IN THE 30S/40S WEDNESDAY NIGHT AND THURSDAY NIGHT...AND THEN IN THE 40S AT NIGHT FOR THE END OF THE WEEK AND INTO THE WEEKEND. && .AVIATION /11Z MONDAY THROUGH FRIDAY/...
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HIGH PRESSURE OVER THE AREA THIS MORNING WEAKENS AND GRADUALLY SHIFTS EAST THROUGH TUESDAY AS A COLD FRONT APPROACHES FROM THE WEST. A COMBINATION OF SHALLOW LOW-LEVEL MOISTURE AND RADIATIONAL COOLING HAS ALLOWED FOR THE DEVELOPMENT OF A SMALL AREA OF IFR CIGS ACROSS SE CT AND RI. KGON REPORTING A CEILING OF 400 FT AT 11Z. DAYTIME HEATING SHOULD DISSIPATE THIS AREA FAIRLY QUICKLY. OTHERWISE VFR THROUGH THE TAF PERIOD. MODERATE CONFIDENCE IN WIND FORECAST. SEA BREEZE WILL BE LIKELY THIS AFT...TIMING COULD BE +/- 1-2 HOURS AT COASTAL TERMINALS. WINDS VEER FROM THE NE THIS MORNING AT LESS THAN 10 KT...TO S/SE BY THIS AFT...WITH LOCAL SEABREEZE ENHANCEMENT. THE NE FLOW WILL HOLD ON ACROSS KLGA INTO MID AFTERNOON AS IS TYPICAL IN A WEAK FLOW DURING THE SPRING. THERE IS ALSO LOW CONFIDENCE IN THE DEVELOPMENT OF IFR STRATUS TONIGHT IN THE ONSHORE FLOW. THERE IS LIMITED GUIDANCE POINTING TO THIS SCENARIO. TYPICALLY...THE FIRST NIGHT OF WEAK ONSHORE FLOW DOES NOT SUPPORT THE DEVELOPMENT OF LOW CLOUDS/FOG. ...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) KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. KISP FCSTER COMMENTS: PATCHY MVFR/IFR CIGS POSSIBLE TO 13Z. .OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... .TUE MORNING...VFR...PATCHY IFR/MVFR POSSIBLE. .TUE AFT-TUE NIGHT...SHRA BECOMING LIKELY...WITH MVFR OR LOWER POSSIBLE. NW-N WINDS G20-25KT AT NIGHT. .WED-THU NIGHT...VFR. NW-N WIND G20-25 KT. .FRI...MVFR OR LOWER POSSIBLE IN AFT WITH A CHANCE OF SHOWERS.
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&& .MARINE... A LIGHT PRESSURE GRADIENT WILL KEEP WINDS 10 KT OR LESS OVER ALL WATERS THROUGH TUESDAY MORNING...AND OVER THE NON-OCEAN WATERS THROUGH TUESDAY AFTERNOON. SOUTHERLY FLOW SHOULD INCREASE TO 10-15 KT OVER THE COASTAL OCEAN WATERS TUESDAY AFTERNOON...HOWEVER THIS SHOULD NOT BE ENOUGH TO BRING SEAS TO 5 FT. COLD FRONT MOVES ACROSS THE WATERS TUESDAY NIGHT...AND THEN HIGH PRES BUILDS EAST FOR THE MIDDLE TO THE END OF THE WEEK. THE PRESSURE GRADIENT TIGHTENS ON THE WATERS FOR WEDNESDAY/THURSDAY. WINDS RAMP UP TO SCA LEVELS LATE TUESDAY NIGHT/WEDNESDAY...AND THERE IS THE POTENTIAL FOR GALES ON EASTERN WATERS WEDNESDAY NIGHT AND THURSDAY. WINDS/SEAS SUBSIDE TO SUB-SCA LEVELS THURSDAY NIGHT...AND THEN SUB-SCA CONDITIONS CURRENTLY EXPECTED FOR THE END OF THE WEEK AND INTO THE WEEKEND. && .HYDROLOGY... THE POTENTIAL FOR SIGNIFICANT PRECIPITATION - WIDESPREAD 1/2 INCH OR MORE - IS LOW THROUGH THE WEEK. NOTE...MINOR FLOODING CONTINUES ALONG THE CONNECTICUT RIVER. FOR ADDITIONAL INFORMATION...PLEASE REFER TO THE LATEST FLOOD WARNINGS FROM NWS TAUNTON MA. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MALOIT/MPS NEAR TERM...MALOIT/MPS SHORT TERM...MALOIT LONG TERM...MPS AVIATION...DW MARINE...MALOIT/MPS HYDROLOGY...MALOIT/MPS

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