Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 260156 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 956 PM EDT SAT APR 25 2015 .SYNOPSIS... A LARGE UPPER LEVEL LOW PRESSURE SYSTEM WILL PERSIST OVER THE NORTHEASTERN UNITED STATES INTO EARLY NEXT WEEK. HIGH PRESSURE BUILDS ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY. MEANWHILE...LOW PRESSURE OVER THE GULF COAST STATES WILL TRACK TO THE MID ATLANTIC COAST BY THURSDAY AND CONTINUING NORTHEAST INTO THE ATLANTIC THROUGH THE END OF THE WEEK. AN UPPER LEVEL DISTURBANCE MAY IMPACT THE AREA ON SATURDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... FORECAST IS ON TRACK. AFTER COLLAB WITH BOX...SOME CONCERN WITH REGARD TO TEMPS OVERNIGHT DUE TO HIGH CLOUDS ENCROACHING FROM THE SOUTH/SOUTHWEST AND MID LEVEL CLOUDS PIVOTING SOUTHWARD ACROSS NEW ENGLAND. ANY ADDITIONAL CLOUD COVER MAY PREVENT TEMPS FROM FALLING QUITE AS LOW AS CURRENT FCST. HOWEVER...LATEST HOURLY GUIDANCE DOES SUGGEST CLEARING OCCURS. LIGHT NORTH FLOW COULD LEAD TO THE COOL TEMPS THAT ARE ALREADY IN THE FORECAST. AS SUCH...FROST ADVISORY REMAINS IN EFFECT. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... ELONGATED UPPER TROUGH OVER NORTHERN NEW ENGLAND BEGINS TO PIVOT SOUTH INTO CENTRAL NEW ENGLAND ON SUNDAY...WITH WEAK SURFACE TROUGH REFLECTION DEVELOPING ALONG THE COASTAL PLAIN. DAYTIME INSTABILITY...STEEPENING MID LEVEL LAPSE RATES...AND CONVERGENCE ALONG SURFACE TROUGH SHOULD ALLOW FOR SCT-BKN AFT/EVE INSTABILITY CU AND ISO-SCT SHOWER DEVELOPING OFF THE HIGHER TERRAIN AND SINKING S/SE. HIGHEST COVERAGE WILL LIKELY BE ACROSS CT IN VICINITY OF SURFACE TROUGH. GUSTY WINDS POSSIBLE WITH ANY SHOWERS WITH INVERTED V SOUNDING. HIGHS GENERALLY IN THE UPPER 50S TO LOWER 60S. UPPER TROUGH CONTINUES TO SINK SE OVER THE REGION SUNDAY NIGHT. DIMINISHING SURFACE INSTABILITY AND CONVERGENCE SHOULD END ANY SHOWER ACTIVITY...BUT MID-DECK SHIELD ASSOCIATED WITH TROUGH APPEARS TO SINK SOUTH OVER THE REGION. THIS SHOULD KEEP TEMPS SEVERAL DEGREES MILDER SUNDAY NIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... A BLOCKY PATTERN LOOKS TO DOMINATE THE FIRST HALF OF NEXT WEEK ACROSS THE CONUS. A LARGE PERSISTENT CUTOFF LOW PRESSURE SYSTEM IS FORECAST TO PLAGUE THE NORTHEAST US THROUGH TUESDAY WHICH WILL RESULT IN GENERALLY MOSTLY CLOUDY CONDITIONS AND SCT SHOWERS MON/MON NIGHT AS SPOKES OF VORTICITY WITHIN THE CYCLONIC FLOW ROTATE THROUGH THE AREA. THIS CUTOFF FINALLY EXITS ON TUE WITH RIDGING BRIEFLY BUILDING IN TUE NIGHT AND WED. DRY CONDS AND PARTLY CLOUDY SKIES ARE EXPECTED. MODEL GUIDANCE REMAINS DIVERGENT WITH HOW QUICKLY THE RIDGE AXIS MOVES THROUGH AND THE NEXT TROUGH APPROACHES. GFS IS FASTER THAN THE EC. WHAT BOTH MODELS DO AGREE ON IS THE PHASING OF A NRN STREAM SHORTWAVE WITH A CUTOFF LOW OVER THE SOUTHERN PLAINS RESULTING IN A DEEP TROUGH THROUGH THE MISSISSIPPI VALLEY TUE NIGHT. THE SFC LOW ASSOCIATED WITH THE CUTOFF TRACKS THROUGH THE GULF COAST STATES TO OFF THE NORTH CAROLINA COAST ON THU AND CONTINUES ON A NE TRACK THROUGH FRI. HOWEVER DUE TO THE DIFFERENCES ALOFT THE EC IS STRONGER...SLOWER AND CLOSER TO THE COAST...BUT CONTINUES TO REMAIN WELL S OF THE FORECAST AREA. HAVE KEPT SCHC POPS ACROSS THE AREA THU AS SEVERAL SHORTWAVES DIVE DOWN FROM THE N DURING THIS TIME. HOWEVER...DUE TO THE UNCERTAINTY IN THE PATTERN EARLIER IN THE FORECAST...THIS IS VERY LOW CONFIDENCE. TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW NORMAL LEVELS THROUGH THE PERIOD. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... A TROUGH OF LOW PRESSURE WILL GIVE WAY TO HIGH PRESSURE BUILDING FROM THE NORTHWEST. WINDS ARE EXPECTED TO TURN TO THE NORTH OVERNIGHT. ONLY SOME MID AND HIGH CLOUDS ARE FORECAST OVERNIGHT. VFR. DURING THE DAY SUNDAY...ANOTHER TROUGH DEVELOPS. NORTHERLY WINDS ARE EXPECTED IN THE MORNING...THEN WINDS WILL VARY BASED ON LOCATION DURING THE AFTERNOON. GENERALLY EXPECT NW WINDS FOR NJ AND LOWER HUDSON VALLEY TERMINALS...WITH POTENTIAL W/SW OR SEA BREEZE WIND FLOW TO THE EAST ON LONG ISLAND AND SRN CT. VFR WITH BROKEN CU AND AC DEVELOPING DURING THE LATE AFTERNOON. A FEW SHOWERS WILL APPROACH FROM THE NORTH...BUT GENERALLY VFR CONDITIONS ARE ANTICIPATED THROUGH 00Z. .OUTLOOK FOR 00Z MONDAY THROUGH THU... .SUN NIGHT...MAINLY VFR. POSSIBLE MVFR WITH SHOWERS EARLY EVE. .MON-MON NIGHT...POSSIBLE MVFR WITH SHOWERS. .TUE-WED NIGHT...VFR. .THU...POSSIBLE MVFR WITH SHOWERS. && .MARINE... A WEAK PRES GRADIENT WILL KEEP SUB-ADVSY CONDS ACROSS THE WATERS THROUGH MUCH OF THE PERIOD. MARGINAL NW GUSTS ARE POSSIBLE LATE MON NIGHT INTO TUE ON THE EASTERN OCEAN WATERS AS THE GRADIENT TIGHTENS. && .HYDROLOGY... SIGNIFICANT PRECIPITATION IS NOT EXPECTED THROUGH NEXT WEEK. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FROST ADVISORY FROM 2 AM TO 8 AM EDT SUNDAY FOR CTZ005>008- 010>012. NY...FROST ADVISORY FROM 2 AM TO 8 AM EDT SUNDAY FOR NYZ067>070-079- 081. NJ...FROST ADVISORY FROM 2 AM TO 8 AM EDT SUNDAY FOR NJZ002-004-103- 105-107. MARINE...NONE. && $$ UPDATE...PW

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