Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 061132 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 732 AM EDT WED MAY 6 2015 .SYNOPSIS... A SLOW MOVING COLD FRONT SOUTH OF LONG ISLAND WILL CONTINUE TO SAG SOUTH OF THE REGION TODAY...ALLOWING HIGH PRESSURE TO BUILD IN FOR THU. A FRONTAL BOUNDARY WILL BACK INTO THE REGION FROM THE NORTHEAST ON FRIDAY...THEN LIFT OUT ON SATURDAY. HIGH PRESSURE OVER THE ATLANTIC THEN REMAINS IN CONTROL THROUGH THE REST OF THE WEEKEND. LOW PRESSURE OFF THE SOUTHEAST COAST WILL TRACK SLOWLY ALONG THE MID ATLANTIC COAST INTO EARLY NEXT WEEK...THEN TRACK OUT TO SEA AS A COLD FRONT APPROACHES FROM THE WEST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FORECAST IS GENERALLY ON TRACK. RADAR IMAGERY LOOKS WORSE THAN REALITY DUE TO A VERY DRY SUBCLOUD LAYER (20 DEGREE DEWPOINT DEPRESSIONS AT THE SFC). LEFT POPS AT HIGH CHC AS A RESULT WITH SCT SHOWERS. HOURLY T/TD NEEDED ADJUSTING AS TEMPS ARE HIGHER THAN FORECAST AND DEWPOINTS ARE LOWER. NO OTHER ADJUSTMENTS NEEDED. THE 00Z MODELS ARE BASICALLY DRY FOR TODAY. HOWEVER...STLT AND RADAR INDICATE BANDS OF SHWRS ROTATING INTO THE REGION FROM THE W...THE REMNANTS OF MIDWEST CONVECTION. THE 00Z OKX SOUNDING HAD A PW OF 1.13...SO THE ADDITIONAL MOISTURE ADVECTION SHOULD ALLOW FOR AT LEAST SOME POCKETS OF MEASURABLE PCPN ACROSS THE SWRN 2/3 OF THE CWA. THE LIMITING FACTOR WILL BE THE DEVELOPING NE FLOW BEHIND THE CDFNT JUST S OF LI...WHERE THE 00Z CHH SOUNDING JUST UPSTREAM HAD A PW OF 0.83. GYX WAS EVEN LOWER AT 0.23. AS A RESULT...POPS WERE CAPPED AT SCT COVERAGE FOR TODAY...WITH DECREASING CHCS FROM NE TO SW IN THE AFTN...ENDING BY THIS EVE. THE CLOUD SHIELD WILL LIKEWISE ERODE...BUT WITH IR SHOWING THE MID CLOUD BELT STILL STRETCHING FROM LAKE ONTARIO WWD TO LAKE MICHIGAN...HAVE FCST A MAINLY OVC DAY. TEMPS A BLEND OF THE GUIDANCE...WITH THE WARMEST READINGS ACROSS THE INTERIOR VALLEYS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... UPR RIDGE BUILDS IN WITH DECREASING MOISTURE AND INCREASING SUBSIDENCE. THERE IS A HINT OF CONVECTIVE INITIATION IN ALL THE 00Z MODELS THU AFTN...BUT IT APPEARS TO BE TERRAIN INDUCED...AND WITH THE WEAK STEERING FLOW DO NOT EXPECT ANY OF THE PCPN TO REACH THE CWA ATTM. THE END RESULT IS A DRY FCST. TEMPS A BLEND OF GUIDANCE TNGT...AND A BLEND OF THE MOSG25 AND NAMDNG5 FOR THU...WHERE THE WEAK GRAD FLOW SHOULD ALLOW FOR EXTENSIVE AND EARLY SEA BREEZE DEVELOPMENT YIELDING MUCH COOLER TEMPS ALONG THE COASTS. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MODEL GUIDANCE LOOKS TO START OFF IN GOOD AGREEMENT WITH AN AMPLIFIED RIDGE OVER THE NERN CONUS AND ERN CANADA. THEY START TO DIVERGE FAIRLY QUICKLY AS THE GFS MOVES THE RIDGE OFFSHORE AND BREAKS IT DOWN QUICKER THAN THE EC. SINCE THIS IS A KNOWN BIAS OF THE GFS...HAVE SIDED WITH THE EC SOLN WHICH HAS SUPPORT FROM THE CMC. AS A RESULT...HAVE KEPT THE WEEKEND DRY...WHICH MAY ALSO CONTINUE INTO MONDAY...ALTHOUGH THERE IS UNCERTAINTY WITH A LOW PRESSURE SYSTEM TRACKING ALONG THE EASTERN SEABOARD EARLY NEXT WEEK AS WELL AS HOW FAR S A FRONTAL BOUNDARY DROPS DOWN FROM THE N. HAVE DECIDED NOT TO MAKE HUGE CHANGES MON THROUGH WED...BUT WE MAY NOT SEE A WIDESPREAD RAINFALL UNTIL AN UPPER TROUGH AND SFC COLD FRONTAL PASSAGE TUE/TUE NIGHT. THERE IS ALSO THE SIGNAL FOR SEVERAL DAYS OF FOG AND STRATUS AT NIGHT AND INTO THE MORNING BEGINNING FRI NIGHT (COULD HAVE PATCHY FOG IN SOME ISOLD SPOTS THU NIGHT) WITH SEVERAL DAYS OF SLY FLOW IN PLACE. HAVE ADDED THIS TO THE FORECAST SAT AND SUN FOR NOW. TEMPS ARE EXPECTED TO BE ABOVE NORMAL LEVELS THROUGH THE PERIOD. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... A COLD FRONT MOVES SOUTH TODAY AS HIGH PRESSURE BUILDS OVER THE TERMINALS THROUGH TONIGHT. VFR THROUGH THE TAF PERIOD. -RA MOVES ACROSS THE TERMINALS THIS MORNING...ENDING AROUND 17Z. NE WINDS THIS MORNING AROUND 10 KT VEER TO THE E AND THEN SE THIS AFTERNOON INTO THE EARLY EVENING HOURS. WINDS LIKELY STAY NE-E AT KSWF THROUGH THE DAY. WINDS BECOME LIGHT AND VARIABLE TONIGHT. 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: TIMING OF WIND SHIFT TO THE SE MAY BE OFF BY +/- AND HOUR OR TWO. KLGA FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE MAY BE OFF BY +/- AND HOUR OR TWO. KEWR FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE MAY BE OFF BY +/- AND HOUR OR TWO. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE MAY BE OFF BY +/- AND HOUR OR TWO. KHPN FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE MAY BE OFF BY +/- AND HOUR OR TWO. KISP FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE MAY BE OFF BY +/- AND HOUR OR TWO. .OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY... .WEDNESDAY NIGHT-FRIDAY...VFR. .SATURDAY-SUNDAY...POTENTIAL FOR IFR OR LOWER IN STRATUS AND/OR FOG AT NIGHT AND THE MORNING. OTHERWISE VFR. && .MARINE... WINDS AND SEAS WILL REMAIN BLW SCA LVLS THRU THU AS HI PRES BUILDS IN FROM THE NW. FOR THU NGT THRU MON...WINDS ARE EXPECTED TO REMAIN BELOW ADVSY CRITERIA THROUGH THE PERIOD...ALTHOUGH COULD GUST AROUND 20 KT SUN AFTN/EVE WITH A TIGHTENING PRES GRADIENT. SEAS COULD REACH MARGINAL SCA LEVELS ON THE OCEAN WATERS SUN NIGHT INTO MON AS SWELLS FROM LOW PRES OFF THE MID ATLANTIC COAST DEVELOP. OTHERWISE...SUB-ADVSY CONDS ARE EXPECTED. && .HYDROLOGY... A FEW HUNDREDTHS OF AN INCH OF PCPN ARE POSSIBLE TODAY. THEREAFTER...NO PCPN IS EXPECTED THROUGH THE WEEKEND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JMC/24 NEAR TERM...JMC SHORT TERM...JMC LONG TERM...24 AVIATION...DS MARINE...JMC/24 HYDROLOGY...JMC/24

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