Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 171959 CCA AFDOKX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE NEW YORK NY 359 PM EDT FRI APR 17 2015 .SYNOPSIS... A WEAK TROUGH OF LOW PRESSURE WILL MOVE THROUGH THIS EVENING. A COLD FRONT WILL APPROACH ON SATURDAY AND PASS THROUGH BY EVENING. HIGH PRESSURE BUILDS BRIEFLY ACROSS THE AREA ON SUNDAY AND THEN GIVES WAY TO AN APPROACHING FRONTAL SYSTEM FROM THE SOUTHWEST ON MONDAY. A FRONTAL WAVE PASSES JUST SOUTH AND EAST OF THE AREA MONDAY NIGHT...FOLLOWED BY A COLD FRONTAL PASSAGE TUESDAY MORNING. A SERIES OF WEAK COLD FRONTS OR TROUGHS WILL MOVE THROUGH DURING THE MIDWEEK PERIOD FOLLOWED BY HIGH PRESSURE AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... TEMPERATURES ARE EXPECTED TO CONTINUE TO RISE INTO THE MID 60S TO NEAR 70 WITH SHOWERS DEVELOPING THIS AFTERNOON AHEAD OF A WEAK SURFACE TROUGH. WEAK DESTABILIZATION IS OCCURRING AS A RESULT OF PARTIAL CLEARING. INSTABILITY MAY BE SUFFICIENT ENOUGH FOR ISOLATED THUNDERSTORMS THIS AFTERNOON...ESPECIALLY ACROSS NJ. SOME SHOWERS/THUNDERSTORMS COULD PRODUCE GUSTY WINDS VIA EVAPORATIVE COOLING OF PRECIPITATION IN A RELATIVELY DRY SUB-CLOUD LAYER. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... WEAK PSEUDO COLD FRONT WILL MOVE THROUGH THIS EVENING...BRINGING ANY LINGERING SHOWER ACTIVITY TO AN END. SKIES SHOULD BECOME MOSTLY CLEAR OVERNIGHT...WITH A WIDE RANGE IN LOW TEMPS EXPECTED...RANGING FROM THE 40S IN MOST PLACES...TO THE 50S INVOF NYC. SAT LOOKS TO BE THE WARMEST DAY OF THE YEAR THUS FAR...WITH MOSTLY SUNNY SKIES...DEEP MIXING WITH H8 TEMPS +8 TO +10C...AND DOWNSLOPE WESTERLY FLOW...LEADING TO HIGHS WELL INTO THE 70S EVEN ALONG THE COAST...AND UPPER 70S WEST OF NYC. GUSTY WINDS WILL LIKELY BEGIN BY LATE MORNING. A POTENT NRN STREAM SHORTWAVE DIVING ACROSS UPSTATE NY AND NEW ENGLAND IN THE AFTERNOON WILL DRIVE A COLD FRONT THROUGH DURING THE EVENING. THIS FRONT WILL BE ACCOMPANIED BY A BAND OF HIGH- BASED STRATOCU AND A NOTICEABLE INCREASE IN WIND...WITH GUSTS 25-35 MPH. && .LONG TERM /SUNDAY THROUGH FRIDAY/... RIDGING BOTH ALOFT AND AT THE SFC TRANSLATES WEST TO EAST ACROSS THE AREA ON SUN. TO THE WEST...AN AMPLIFYING FULL LATITUDE TROF WILL LIFT NORTH AND EAST ACROSS THE GREAT LAKES AND INTO THE NE MON INTO TUE. GLOBAL MODELS IN PARTICULAR...THE 12Z GFS AND ECMWF...ARE IN RELATIVELY GOOD AGREEMENT WITH SMALL TIMING DIFFERENCES...BUT LARGER DIFFERENCES EXIST WITH QPF. THIS WILL RESULT IN AN APPROACHING FRONTAL SYSTEM THAT WILL HAVE BOTH ATLANTIC AND GULF MOISTURE TO WORK WITH. PWAT VALUES WILL BE ON THE ORDER OF 2SD ABOVE NORMAL. A FRONTAL WAVE IS FORECAST TO PASS JUST SOUTH OF THE AREA MON NIGHT...IN ESSENCE KEEPING THE AREA JUST NORTH OF THE WARM FRONT. THE COLD FRONT FOLLOWS TUE MORNING. STRONG WAA ON MON WITH A 50-60 KT SE LLJ WILL PRODUCE MODERATE TO OCCASIONALLY HEAVY RAIN FOR MUCH OF THE DAY. INSTABILITY ALOFT COULD ALSO RESULT IN SOME ELEVATED THUNDER MON NIGHT. RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE FORECAST...WITH THE HIGHEST AMOUNTS FROM NYC AND POINTS NORTH AND WEST. THE SE FLOW WILL ENHANCE OROGRAPHIC LIFT. GUST UP TO 25 TO 30 MPH WILL POSSIBLE AT THE SFC ON MON...BUT TEMP PROFILES WILL BE INVERTED LIMITING ANY STRONGER WINDS FROM COMING DOWN. CONDITIONS DRY OUT TUE INTO WED WITH A SERIES OF WEAK FRONTS AND/OR TROUGHS MOVING ACROSS THE REGION. THESE WILL REINFORCE A SEASONABLE AIRMASS. HIGH PRESSURE THEN FOLLOWS FOR THE END OF THE WEEK. UPPER AIR PATTERN WILL BE DOMINATED BY A BROAD...FLAT TROUGH EAST OF THE MS RIVER VALLEY. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
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WEAK COLD FRONT APPROACHES PASSES THROUGH THIS EVENING. CONDITIONS WILL CONTINUE TO IMPROVE THROUGH THE REST OF THE AFTERNOON. HOWEVER...SCATTERED -SHRA WILL MOVE INTO THE AREA...MAINLY BETWEEN 21Z AND 02Z. A RETURN TO MVFR CONDITIONS IS POSSIBLE IN ANY -SHRA. A TSTM IS ALSO POSSIBLE...BUT CONFIDENCE IS NOT HIGH ENOUGH TO MENTION IN TAFS. KGON WILL LIKELY HOLD ONTO AT LEAST MVFR CONDITIONS THROUGH THE AFTERNOON...AND COULD REMAIN MVFR CONDITIONS UNTIL BETWEEN 06Z-09Z. WINDS SHIFT TO THE NW TONIGHT WITH VFR CONDITIONS BEHIND THE COLD FRONT...THEN BACK TO THE W OR SW SAT MORNING. WINDS WILL GUST 20-25 KT ON SAT...WITH HIGHER GUSTS POSSIBLE. SEA BREEZE DEVELOPMENT POSSIBLE ON SAT. BEST CHANCES FOR SEA BREEZES ARE WITH KJFK...KISP...AND KBDR. KJFK FCSTER COMMENTS: MVFR CONDITIONS MAY LAST A COUPLE OF HOURS LONGER THAN IS FORECAST. KLGA FCSTER COMMENTS: MVFR CONDITIONS MAY LAST A COUPLE OF HOURS LONGER THAN IS FORECAST. KEWR FCSTER COMMENTS: MVFR CONDITIONS MAY LAST A COUPLE OF HOURS LONGER THAN IS FORECAST. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: MVFR CONDITIONS MAY LAST A COUPLE OF HOURS LONGER THAN IS FORECAST. KHPN FCSTER COMMENTS: MVFR CONDITIONS MAY LAST A COUPLE OF HOURS LONGER THAN IS FORECAST. KISP FCSTER COMMENTS: IFR CONDITIONS MAY LAST A COUPLE OF HOURS LONGER THAN IS FORECAST. .OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY... .FRI NGT...VFR. .SAT...VFR. SFC WND NW 10-15KT INCREASING WITH GUSTS TO G25KT LATE AFTN. OCCASIONAL GUSTS TO 30 KT POSSIBLE. .SUN...VFR. SFC WND LIGHT NE BECOMING SE 10KT IN THE AFTN. .MON...MVFR BECOMING IFR. INCREASING ESE SFC WND. G30-35KT IN AFTN. .TUE...MVFR BECOMING VFR. G20-25KT. .WED...VFR BECOMING SUB VFR BY THE AFTN.
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&& .MARINE... S-SW FLOW 10-15 KT AHEAD OF AN APPROACHING WEAK COLD FRONT BUILDING OCEAN SEAS GENERALLY TO 3 TO 4 FT ON THE ERN OCEAN WATERS THIS AFTERNOON AND EVENING. NEAR SHORE SCA CONDS MAY BE POSSIBLE ON ALL WATERS SAT AFTERNOON AND EARLY EVENING WITH THE APPROACH AND PASSAGE OF A COLD FRONT. HIGH PRESSURE BUILDS EAST OF THE WATERS LATE SUN AFT WITH AN APPROACHING FRONTAL SYSTEM FROM THE WEST. THIS WILL RESULT IN A STRENGTHENING SE FLOW SUN NIGHT INTO MON WITH SCA CONDITIONS LIKELY ACROSS ALL WATERS. SEAS WILL BUILD TO 7 TO 10 FT ON MON...THEN WILL BE SLOW TO SUBSIDE MON NIGHT INTO TUE. SUB-SCA CONDITIONS ARE EXPECTED ACROSS THE REMAINING WATERS LATE MON NIGHT INTO WED. && .FIRE WEATHER... DRY WEATHER...MINIMUM RH 20-30 PERCENT...AND WINDS GUSTING TO 25-35 MPH WILL LEAD TO ELEVATED POTENTIAL FOR FIRE GROWTH/SPREAD SAT AFTERNOON AND EARLY EVENING. SEVERAL WIND SHIFTS ARE EXPECTED THROUGH THE DAY...CREATING AN ADDITIONAL HAZARD WITH ANY ONGOING FIRES. INITIALLY NORTHWEST WINDS WILL SHIFT TO WEST- SOUTHWEST THEN SOUTHWEST THROUGH THE AFTERNOON...BEFORE RAPIDLY TURNING NORTHWEST AGAIN AROUND 6-7 PM WITH THE APPROACH/PASSAGE OF ANOTHER COLD FRONT. GUSTS MAY BRIEFLY STRENGTHEN AFTER THE COLD FRONTAL PASSAGE. A FIRE WEATHER WATCH IS IN EFFECT FROM 12 PM TO 8 PM GIVEN EXPECTED WEATHER CONDITIONS AND AFTER FEEDBACK FROM FIRE WEATHER OFFICIALS REPORTING DRY FUEL CONDITIONS. && .HYDROLOGY... THERE IS THE POTENTIAL FOR SIGNIFICANT RAINFALL WITH AN APPROACHING FRONTAL SYSTEM MONDAY INTO MONDAY NIGHT. STORM TOTAL RAINFALL WITH THIS SYSTEM WILL BE FROM 1 TO 2 INCHES...WITH THE HIGHEST AMOUNTS FROM NYC AND POINTS NORTH AND WEST. LOCALIZED HIGHER AMOUNTS WILL BE POSSIBLE IN THE HILLS NORTH AND WEST. 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. .COASTAL FLOODING... A PROLONGED PERIOD OF SE FLOW LATE SUN NIGHT INTO MON EVE WILL LIKELY RESULT IN WIDESPREAD MINOR COASTAL FLOODING. ASTRONOMICAL HIGH TIDES WILL BE RUNNING HIGH FOLLOWING A NEW MOON ON SAT. IN SOME CASES...DEPARTURES OF ONLY HALF A FOOT ABOVE NORMAL ARE NEEDED. STORM SURGE IS LIKELY TO PRODUCE WATERS LEVELS 1 TO 1 1/2 FT ABOVE NORMAL. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR CTZ005>012. NY...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR NYZ067>075-078>081-176>179. NJ...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR NJZ002-004-006-103>108. MARINE...NONE. && $$ SYNOPSIS...MD NEAR TERM...MD SHORT TERM...MD LONG TERM...DW AVIATION...JP MARINE...MD/DW FIRE WEATHER... HYDROLOGY...MD

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