Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 121114 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 714 AM EDT SAT JUL 12 2014 .SYNOPSIS... HIGH PRESSURE ACROSS THE REGION TODAY WILL PUSH OFFSHORE TONIGHT INTO SUNDAY. A WARM FRONT MOVES NORTH OF THE REGION SUNDAY WITH ITS ASSOCIATED COLD FRONT APPROACHING THE AREA. THIS WILL BE MOVING SLOWLY EAST...EVENTUALLY MOVING INTO THE AREA MONDAY AND STALLING THROUGH EARLY NEXT WEEK. SMALL WEAK LOWS FORMING ALONG THE FRONT WILL PASS THROUGH AND EVENTUALLY PUSH THE FRONT TO THE EAST BY WEDNESDAY. HIGH PRESSURE WILL BUILD ACROSS THURSDAY INTO FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FORECAST ON TRACK WITH ONLY SLIGHT ADJUSTMENTS MADE TO CLOUDS...TEMPERATURES AND DEWPOINTS TO BETTER MATCH OBSERVED TRENDS. HIGH PRESSURE ACROSS THE REGION WILL ALLOW FOR INITIALLY LIGHT WINDS THIS MORNING. PATCHY FOG BURNS OFF SHORTLY AFTER THE ONSET OF SOLAR INSOLATION THIS MORNING. STILL LOOKING AT A WEAK PRESSURE GRADIENT AND HEIGHT GRADIENT ALOFT WITH JET STREAM STILL WELL NORTH AND WEST OF THE REGION. THIS WILL ALLOW FOR A MAINLY DRY DAY BUT WITH WARMER AIR BEING ADVECTED IN AS MORE OF A LOW LEVEL SOUTHWEST FLOW DEVELOPS. THIS WILL INCREASE INSTABILITY AND MODELS INDICATE SURFACE TROUGH DEVELOPMENT TO THE WEST OF THE REGION WITH DAYTIME HEATING. THIS MAY PROVIDE ENOUGH CONVERGENCE FOR A SHOWER OR THUNDERSTORM...BUT POPS ARE JUST SLIGHT CHANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... ANY CONVECTION EXPECTED TO QUICKLY DISSIPATE AFTER THE LOSS OF DAYTIME HEATING AND THEREBY INSTABILITY SINCE ALOFT THE WEAK HEIGHT GRADIENT PERSISTS. THIS LACK OF SYNOPTIC FORCING WILL KEEP CONDITIONS DRY TONIGHT. THE ESTABLISHMENT OF SOUTHERLY FLOW WILL BECOME MORE LOCKED INTO PLACE. THIS WILL BEGIN THE TRANSITION TO MORE OF A HUMID AND WARM AIRMASS. WE WILL SEE THIS REFLECTED IN NIGHT TIME TEMPERATURES BEING SEVERAL DEGREES WARMER THAN THOSE OF THE PREVIOUS NIGHT DUE TO ONSHORE FLOW AS WELL AS EXTRA CLOUDS. ONE FEATURE TO NOTE THAT IS DRIVING THIS TRANSITION IS AN UNUSUALLY DEEP CUTOFF LOW IN ONTARIO THAT WILL BE PUSHING SOUTH INTO THE GREAT LAKES. ASSOCIATED WITH THIS WILL BE A DEEP TROUGH AND STRONG UPPER LEVEL JET...BOTH OF WHICH WILL BE SLOWLY MOVING SOUTH AND EAST TOWARDS THE REGION SUNDAY THROUGH MONDAY NIGHT. A WARM FRONT AT THE SURFACE MOVES NORTH OF THE AREA SUNDAY AND THEN AN ASSOCIATED COLD FRONT SLOWLY APPROACHES FROM THE WEST...EVENTUALLY STALLING IN OUR REGION EARLY NEXT WEEK WITH SMALL LOWS MOVING ALONG IT. THE WEATHER WILL BECOME INCREASINGLY UNSETTLED WITH THE COLDER TEMPERATURES ALOFT AND THE CONTINUED WARM AND MOIST AIR ADVECTION NEAR THE SURFACE. SHOWERS AND THUNDERSTORMS WILL BECOME MORE FREQUENT ACROSS WESTERN PARTS OF THE REGION SUNDAY AND WILL REACH THE REST OF THE EASTERN PARTS OF THE REGION SUNDAY NIGHT INTO MONDAY. CHANCES WILL BE INCREASING GOING THROUGH TIME. THE BULK SHEAR 0-6 KM INCREASES TO AROUND 20-25 KT SUNDAY AND SUNDAY NIGHT WITH SHEAR MORE AROUND 25-35 KT MONDAY THROUGH MONDAY NIGHT. THIS WILL ALLOW FOR STRONGER THUNDERSTORMS TO FORM. THE CONTINUED WARM AND MOIST AIR ADVECTION WILL ALLOW FOR A PERSISTENT PWAT OF NEAR 2 INCHES...SO THIS WILL ENABLE THUNDERSTORMS TO PRODUCE HEAVY RAIN. PARALLEL FLOW FROM LOW TO UPPER LEVELS WILL ENABLE OF TRAINING OF CONVECTION...ALLOWING FOR MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS TO MOVE ACROSS THE SAME AREA. TEMPERATURES ARE FORECAST TO BE NEAR TO SLIGHTLY ABOVE NORMAL. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE COLD FRONT CONTINUES TO LINGER WITHIN THE LOCAL AREA THROUGH TUESDAY NIGHT. AS A RESULT...EXPECT ROUNDS OF SHOWERS AND THUNDERSTORMS CONTINUING THROUGH EARLY WEDNESDAY...AS WEAK LOWS MOVE ALONG THE STALLED FRONT. DRIER AIR MOVES IN FOR LATER ON WEDNESDAY AND THROUGH THE END OF THE WEEK. HIGH TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE NORMAL ON AVERAGE ACROSS THE REGION TUESDAY AND THEN SLIGHTLY BELOW NORMAL ON AVERAGE WEDNESDAY THROUGH FRIDAY. LOW TEMPERATURES AT NIGHT ARE FORECAST TO BE SLIGHTLY ABOVE NORMAL TUESDAY NIGHT AND TREND TO SLIGHTLY COOLER THAN NORMAL FOR THE REMAINDER OF THE WEEK. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... HIGH PRESSURE WILL REMAIN JUST OFFSHORE THROUGH TONIGHT..THEN MOVE FARTHER OFFSHORE SUNDAY AS A COLD FRONT APPROACHES. LIGHT AND VARIABLE WIND EARLY BECOMES SOUTHERLY...GENERALLY 10 KT OR LESS. WITH SEA BREEZE ENHANCEMENT STRONGER WIND WILL BE LIKELY AFTER 17Z ALONG THE COAST...WITH KJFK AS HIGH AS 15 KT. MVFR FOG DEVELOPMENT MORE LIKELY TONIGHT WITH A LIGHT ONSHORE FLOW. FEW TO SCATTERED 005 KFT TO 010 KFT CLOUDS POSSIBLE. LOW CHANCE OF IFR CEILINGS ALONG THE COAST AFTER 09Z. .OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY... .SUNDAY MORNING...VFR. SOUTH WIND GUSTING UP TO 20 KT. .SUNDAY AFTERNOON-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. && .MARINE... THE CENTER OF HIGH PRESSURE WILL REMAIN OVER THE FORECAST WATERS THROUGH THIS MORNING...THEN DRIFT OFFSHORE THROUGH MONDAY AS A COLD FRONT APPROACHES FROM THE WEST. LIGHT WIND EARLY THIS MORNING WILL BECOME SOUTHERLY. CONDITIONS WILL REMAIN TRANQUIL TODAY THROUGH SUNDAY. HOWEVER...LATE SUNDAY THE SOUTHERLY WIND BEGINS TO INCREASE AND SEAS ON THE OCEAN WILL LIKELY BUILD TO SMALL CRAFT LEVELS BY LATE SUNDAY NIGHT. THE AMBROSE JET WILL INCREASE SUNDAY INTO SUNDAY EVENING AND SOME GUSTS IN THE VICINITY MAY BE NEAR SMALL CRAFT LEVELS FOR SEVERAL HOURS. THE STRONG SOUTHERLY FLOW CONTINUES AHEAD OF THE APPROACHING COLD FRONT AND SEAS ON THE OCEAN CONTINUE AT SMALL CRAFT LEVELS MONDAY INTO TUESDAY NIGHT. THE COLD FRONT MOVES ACROSS THE WATERS LATE TUESDAY NIGHT INTO WEDNESDAY. BELOW SCA CONDITIONS SHOULD RETURN BY WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS TOWARD THE WATERS THROUGH THURSDAY. && .HYDROLOGY... NO WIDESPREAD SIGNIFICANT HYDROLOGIC ISSUES EXPECTED THROUGH SUNDAY MORNING. THERE IS THE POTENTIAL FOR SIGNIFICANT RAINFALL FROM LATE SUNDAY INTO EARLY WEDNESDAY. AT THIS TIME THERE IS TOO MUCH UNCERTAINTY TO SPECIFY EXACT AMOUNTS OR SPECIFIC THREATS...OTHER THAN TO NOTE FLOODING IS POSSIBLE IN AREAS THAT EXPERIENCE ROUNDS OF LOCALLY HEAVY RAINFALL. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...FIG/JM NEAR TERM...JM SHORT TERM...JM LONG TERM...FIG AVIATION...MET MARINE...FIG/MET HYDROLOGY...FIG/JM

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