Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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 131455 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1055 AM EDT SUN JUL 13 2014 .SYNOPSIS... HIGH PRESSURE OFF THE NORTHEAST TO MID ATLANTIC COAST WILL CONTINUE MOVING OFFSHORE THROUGH TODAY AS A COLD FRONT SLOWLY APPROACHES FROM THE WEST. THE FRONT MOVES INTO THE REGION MONDAY AND BECOMES NEARLY STATIONARY THROUGH WEDNESDAY. HIGH PRESSURE RETURNS FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WEAK INSTABILITY COINCIDING WITH A MID LEVEL SHORT WAVE THIS MORNING MAY RESULT IN AN ISOLATED SHOWER ALMOST ANYWHERE IN THE FORECAST AREA. LARGE AREA OF INSTABILITY STRATA CU FROM EASTERN PA INTO WESTERN LI/SW CT...WILL WORK EAST AND GRADUALLY LIFT TROUGH THIS AFTERNOON. EVEN SO...UPSTREAM MID AND HIGH CLOUDS WILL WORK IN TROUGH THE DAY WITH PARTLY TO MOSTLY CLOUDY CONDITIONS. A BROAD UPPER TROUGH IN THE NORTHERN STREAM...WITH A CLOSED UPPER LOW MOVES INTO THE NORTHERN GREAT LAKES REGION BY THIS EVENING AS HEIGHTS SLOWLY FALL ACROSS THE NORTHEAST. AT THE SURFACE A COLD FRONT MOVES INTO UP STATE NEW YORK INTO WESTERN PENNSYLVANIA. A WEAK SURFACE TROUGH DEVELOPS IN THE AREA BY THE AFTERNOON AS A WEAK UPPER SHORTWAVE AND VORT MAX MOVES TOWARD THE AREA. WHILE CAPE JUST UNDER 1000 J/KG AND INSTABILITY WILL BE LIMITED THE SURFACE TROUGH AND SHORTWAVE WILL PROVIDE THE TRIGGER FOR SCATTERED THUNDERSTORMS THIS AFTERNOON. THE FAR EASTERN SECTIONS MAY REMAIN DRY UNTIL THIS EVENING AS THE SHORTWAVE WILL BE SLOWLY MOVING EAST. LOCALLY MODERATE RAINFALL IS POSSIBLE. A SOUTHERLY FLOW AHEAD OF THE COLD FRONT KEEPS THE REGION IN A WARM AND HUMID AIR MASS WITH DEW POINTS IN THE MID TO UPPER 6OS...POSSIBLE INTO THE LOWER 70S THIS AFTERNOON. THERE IS A HIGH RISK OF RIP CURRENTS AT THE OCEAN BEACHES TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... THE UPPER TROUGH AND CLOSED LOW CONTINUE TO MOVE SLOWLY EAST TONIGHT INTO MONDAY AS THE SURFACE COLD FRONT MOVES INTO THE AREA AND BECOMES NEARLY STATIONARY. WITH THE LOSS OF HEATING INSTABILITY LOWERS AND CAPE VALUES DECREASE. HOWEVER THERE IS STILL SOME WEAK LIFT AND A SURFACE TOUGH IN THE AREA AS ANOTHER SHORTWAVE MOVES THROUGH. WILL KEEP THE CHANCE OF THUNDERSTORMS THROUGH THE NIGHT AND INTO MONDAY MORNING...HOWEVER WITH LOWER POPS. MONDAY AFTERNOON A STRONGER VORT MAX ROTATES THROUGH THE UPPER TROUGH...AND INSTABILITY INCREASES WITH DAYTIME HEATING. CLOUD COVER MAY LIMIT THE AMOUNT AND HEATING AND INSTABILITY. HOWEVER...FORCING WILL AVAILABLE WITH THE SHORTWAVE. MOISTURE INFLUX INTO THE REGION AND SLOW...AND TRAINING STORMS WILL LEAD TO THE POTENTIAL FOR HEAVY RAN FALL FLASH FLOODING IN THE AFTERNOON. SOME OF THE THUNDERSTORMS ACROSS PORTIONS OF THE LOWER HUDSON VALLEY...NORTHEASTERN NEW JERSEY AND INTO THE NYC METRO MAY BECOME SEVERE WITH THE POTENTIAL FOR SOME DAMAGING WIND GUSTS. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... MONDAY NIGHT THE THREAT OF STRONG TO SEVERE STORMS CONTINUES ACROSS WESTERN SECTIONS AS THE ATMOSPHERE BEGINS TO STABILIZE. ALSO THE HEAVY RAINFALL AND FLASH FLOODING POTENTIAL REMAINS. SEE HYDROLOGY SECTION FOR FURTHER DETAILS. HEAVY RAIN AND LIKELY POPS CONTINUE THROUGH TUE MORNING. AREAS EAST OF NYC...WITH THE STABILIZING SOUTHERLY FLOW...THERE WILL BE LESS OF A CHANCE OF STRONG STORMS. STARTING TUE MORNING...CONFIDENCE DROPS IN POP AMOUNTS FOR TUESDAY. LARGE DISCREPANCY IN MODEL GUIDANCE WITH THE ONE EXTREME...THE NAM..WITH NO PRECIP WEST OF NYC AFTER 12Z. ON THE OTHER SIDE...THE 12/12Z ECMWF IS THE SLOWEST WITH PRECIP OVER THE LONGEST PERIOD. THE ECMWF BRINGS THE MAIN COLD FRONT THROUGH LATE WED WHILE GFS/GEFS/CMC HAS IT THROUGH BY WED MORNING. WILL KEEP CHANCE POPS THROUGH WED MORNING TO ACCOUNT FOR THIS BUT TRENDS WILL HAVE TO BE MONITORED. CANNOT COMPLETELY RULE OUT THIS SOLUTION. IF THIS SOLUTION IS CORRECT...TUES WILL BE ANOTHER DAY OF HEAVY RAIN AND POTENTIALLY STRONG STORMS WITH 0-6KM SHEAR OF 45-50 KT BUT LESS CAPE THAN MONDAY. BEHIND THE FRONT...A DEEP UPPER TROUGH WILL CONTINUE ITS WAY EAST WITH HIGH PRESSURE BUILDING IN AT THE SURFACE. ZONAL FLOW RETURNS FOR THE END OF THE WEEK. HIGHS MON-TUE WILL BE IN THE LOWER TO UPPER 80S WITH LOWS REMAINING IN THE LOWER 70S. TEMPERATURES THU-SAT WILL BE GENERALLY NEAR TO SLIGHTLY BELOW SEASONAL NORMALS. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... HIGH PRESSURE CONTINUES MOVING OFFSHORE WITH A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST THROUGH THE TAF PERIOD. INITIAL MVFR FOR CITY AND INTERIOR TERMINALS IS EXPECTED TO IMPROVE TO VFR IN THE NEXT FEW HOURS. BRIEF SHOWER POSSIBLE THIS MORNING. SHOWERS/THUNDERSTORM CHANCES INCREASE LATE THIS AFTERNOON AND EVENING FOR KSWF. SHOWER/STORMS MAY SPREAD EAST LATE THIS EVENING...BUT UNCERTAINTY ON WHETHER OR NOT UNCERTAINTY ON WHETHER OR NOT CONVECTION HOLDS TOGETHER TONIGHT...SO LEFT OUT OF TAFS FOR NOW. WINDS GENERALLY 180-220 DEGREES DIRECTION WITH SPEEDS INCREASING TO 10-15 KT WITH GUSTS NEAR 20 KT FOR THE AFTERNOON TO EARLY EVE WITH WIND SPEEDS A FEW KTS HIGHER FOR KJFK AND KLGA. WINDS SUBSIDE AGAIN THEREAFTER. MORE STRATUS/FOG WILL BE POSSIBLE TONIGHT WITH MVFR OR LOWER CONDITIONS BEFORE IMPROVING LATER ON MONDAY. .OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY... .MONDAY-WEDNESDAY...SCATTERED TO NUMEROUS SHRA/TSTMS. STRONGER TSTMS DURING THIS TIME FRAME COULD PRODUCE PERIODS OF MVFR OR LOWER CONDITIONS...LOCALLY HEAVY RAINFALL...AND GUSTY WINDS. CONDITIONS IMPROVE LATE WEDNESDAY. .THURSDAY...VFR. && .MARINE... A STEEPENING PRESSURE GRADIENT DEVELOPS WITH HIGH PRESSURE MOVING OFFSHORE BUT A DEEPENING PARENT LOW MOVING EAST IN SOUTHEAST CANADA. THERE WILL BE AN ASSOCIATED COLD FRONT APPROACHING THE WATERS SLOWLY THROUGH TONIGHT...EVENTUALLY ARRIVING MONDAY AND STALLING IN THE AREA THROUGH MIDWEEK WITH MULTIPLE LOWS RIDING ALONG THE FRONT. WINDS WILL INCREASE TODAY OUT OF THE SOUTH-SOUTHWEST WITH AMBROSE JET DEVELOPMENT LIKELY TOWARDS WESTERN LONG ISLAND. SUSTAINED SPEEDS ARE FORECAST TO BE AROUND 10-15 KT WITH GUSTS IN THE 20-25 KT RANGE THIS AFTERNOON INTO THE EVENING. THIS WILL BE A PROLONGED SOUTHERLY FETCH THAT WILL CONTINUE THROUGH EARLY IN THE NEXT WEEK. SEAS WILL BUILD TO AROUND 5 FT ON THE OCEAN THIS AFTERNOON AND STAY INTO THE EARLY PART OF THE WEEK. THEREFORE...SCA CONDITIONS ARE EXPECTED ON ALL WATERS THIS AFTERNOON AND THIS EVENING WITH WINDS SUBSIDING THEREAFTER. HOWEVER...THE OCEAN SEAS WILL STILL BE BUILDING DUE TO THE SOUTHERLY FETCH. HENCE...THE SCA REMAINS ON THE OCEAN THROUGH ALL OF TONIGHT AND FOR THE OCEAN EAST OF FIRE ISLAND INLET...THROUGH MONDAY. WHILE WINDS MAY BE MORE MARGINAL FOR MEETING SCA CRITERIA FOR MONDAY NIGHT THROUGH WEDNESDAY...THE OCEAN SEAS WILL LIKELY STILL BE MEETING SCA CRITERIA WITH SEAS FORECAST OF 4-6 FT. && .HYDROLOGY... A SIGNIFICANT RAINFALL IS POSSIBLE BEGINNING LATE THIS AFTERNOON AND CONTINUING INTO EARLY WEDNESDAY. TOTAL RAINFALL THROUGH THIS PERIOD IS EXPECTED TO RANGE FROM AROUND 1 1/2 INCHES TO 2 1/2 INCHES WITH LOCALLY 3 TO 3 1/2 INCH AMOUNTS POSSIBLE. THE HEAVIEST RAINFALL IS EXPECTED TO OCCUR MONDAY AFTERNOON INTO EARLY TUESDAY. URBAN FLOODING IS POSSIBLE WITH THE HEAVY RAINFALL. ALSO...AT THIS TIME...THERE IS A LOW CHANCE OF FLASH FLOODING ACROSS THE REGION MONDAY AFTERNOON AND MONDAY NIGHT. && .TIDES/COASTAL FLOODING... ASTRONOMICAL HIGH TIDES REMAIN HIGH DUE TO THE RECENT FULL MOON OF SATURDAY MORNING. THE HIGH TIDE CYCLES THIS EVENING WILL BE SIMILAR TO WHAT OCCURRED SATURDAY NIGHT WITH TIDAL DEPARTURES 2 TO 3 TENTHS OF A FOOT ABOVE THE ASTRONOMICAL HIGH TIDE. THIS WILL BRING SOME LOCATIONS TO JUST UNDER THE MINOR COASTAL FLOODING THRESHOLDS DURING THE HIGH TIDE CYCLE...AROUND 10 PM ALONG THE SOUTH SHORE AND MIDNIGHT TO 1 AM SUNDAY IN THE LONG ISLAND SOUND. HOWEVER WITH A STRENGTHENING...AND PERSIST ONSHORE FLOW TODAY ALONG WITH A SOUTHEAST SWELL...TIDAL DEPARTURES MAY RUN A LITTLE HIGHER AND BRING SOME LOCATIONS...ESPECIALLY ALONG THE SOUTH SHORE BACK BAYS...TO OR JUST ABOVE MINOR FLOODING THRESHOLDS TONIGHT. WITH LOW CONFIDENCE OF WIDESPREAD MINOR COASTAL FLOODING OCCURRING AND THE HIGH TIDE CYCLE TONIGHT WILL NOT ISSUE ANY STATEMENTS AT THIS TIME. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ330-335- 338-340-345. SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ350-353. SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ355. && $$ SYNOPSIS...MET NEAR TERM...MET/DW SHORT TERM...MET LONG TERM...LN/MET AVIATION...DS MARINE...JM HYDROLOGY...MET TIDES/COASTAL FLOODING...MET

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