Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 300231 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1031 PM EDT MON JUN 29 2015 .SYNOPSIS... AS LOW PRESSURE MOVES INTO THE CANADIAN MARITIMES THROUGH TONIGHT...HIGH PRESSURE WILL BUILD INTO THE NORTHEAST. ANOTHER LOW WILL MOVE THROUGH THE EASTERN GREAT LAKES ON TUESDAY WITH ITS WARM FRONT APPROACHING FROM THE SOUTH. IT MOVES THROUGH WEDNESDAY. AS A COLD FRONT MOVES SLOWLY SOUTHEAST ACROSS THE REGION WEDNESDAY NIGHT...IT WILL BECOME NEARLY STATIONARY SOUTH OF THE AREA THURSDAY THROUGH MONDAY AS A SERIES OF LOW PRESSURE SYSTEMS MOVE EAST ALONG THE FRONT. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... WINDS CONTINUE TO DIMINISH WITH LOSS OF DIURNAL HEATING AND WITH GRADIENT SLACKENING AS HIGH PRES BUILDS IN FROM THE EAST. WITH CLEARING SKIES AND LIGHT WINDS...RADIATIONAL COOLING WILL ALLOW FOR RELATIVELY COOLER TEMPS IN THE INTERIOR AND RURAL SECTIONS OF THE REGION. LOWS WILL BOTTOM OUT IN THE MID 50S TO UPPER 60S. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... THE HIGH PRESSURE WILL STILL BE PREVALENT TUESDAY WITH THE RIDGE OFFSHORE. CLOUDS WILL INCREASE FROM THE WEST DURING THE DAY WITH AN INCREASING CHANCE OF SHOWERS MAINLY WEST OF NYC TOWARDS THE LATTER PORTION OF THE DAY. MORE SUN EXPECTED FARTHER EAST THAN THE PREVIOUS DAY AND DESPITE A SE FLOW...TEMPS ALOFT AT 850MB WARM A FEW DEGREES COMPARED TO THE PREVIOUS DAY AS WELL. AS A RESULT...HIGH TEMPS WILL BE A FEW DEGREES WARMER AS WELL. HIGHS RANGE FROM THE LOW TO MID 80S. FOR TUESDAY NIGHT AND WEDNESDAY...A LOW WILL BE DEVELOPING IN THE OHIO VALLEY INTO THE EASTERN GREAT LAKES. ITS ASSOCIATED WARM FRONT WILL BE APPROACHING FROM THE SOUTHWEST. IT WILL MAKE SLOW PROGRESS AND NOT MOVE THROUGH UNTIL DURING THE DAY WEDNESDAY. THE CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS BECOMES MORE WIDESPREAD TUESDAY NIGHT. INSTABILITY AT THE SURFACE INCREASES LATE TUESDAY NIGHT AND WEDNESDAY...MAKING FOR A RELATIVELY HIGHER CHANCE OF THUNDERSTORMS. SHOWERS WILL BE LIKELY LATE TUESDAY NIGHT AND WEDNESDAY WITH SCATTERED EMBEDDED THUNDERSTORMS FROM TIME TO TIME. MORE OF SYNOPTIC FORCING CONVEYED BY MODELS WITH SHARPENING SHORTWAVE EARLY WEDNESDAY TRAVERSING THE REGION AND ASSOCIATED UPPER LEVEL SOUTHERLY JET STREAK. THIS WILL HELP ADVECT IN GREATER MOISTURE WITH MORE SOUTHERLY FLOW THROUGH THE ATMOSPHERE. LOWS TUESDAY NIGHT CONVEYED THE WARMER SIDE OF GUIDANCE WITH VALUES RANGING FROM THE LOW TO UPPER 60S. TOOK COOLER SIDE OF GUIDANCE FOR HIGHS WEDNESDAY WITH A RANGE FROM THE UPPER 70S TO LOWER 80S. THERE IS A MODERATE RISK OF RIP CURRENTS AT OCEAN BEACHES ON TUESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... FORECAST UNCERTAINTY REGARDING TIMING AND LOCATION OF RAIN WILL REMAIN HIGH LEADING TO A LOW CONFIDENCE LONG TERM FORECAST. WHAT WE KNOW...MEAN POSITIONS OF THE UPPER LVL RIDGE ACROSS THE WESTERN U.S. AND EASTERN U.S. WILL NOT CHANGE MUCH. SHORT WAVES WILL CONTINUE TO DEVELOP AND ROTATE AROUND THE POLAR VORTEX JUST NORTH OF HUDSON BAY CANADA. AS EACH SHORT WAVE DROPS FAR ENOUGH SE...IT WILL BRING INCREASES CHANCES OF SHOWERS AND TSTMS. WHAT WE DONT KNOW...THE SPECIFIC TRACKS...INTENSITY AND TIMING OF THE APPROACHING SHORT WAVES. WED NIGHT...WX CONDITIONS ARE FCST TO IMPROVE WITH THE SLOW PASSAGE OF A COLD FRONT MVG SE ACROSS THE REGION...BRINGING A TEMPORARY END TO A ROUND OF SHOWERS AND TSTMS. THU THROUGH THU NIGHT...THIS FCST DEPENDS ON HOW FAR SOUTH THE FRONT MAKES IT AS A WAVE OF LOW PRES DEVELOPS ALONG IT AND MVS EAST. INCLUDED A CHC OF TSTMS MAINLY THU AFTN AND EVE WITH THE APPROACH OF THIS LOW AND AN UPPER LVL SHORT WAVE. FRI...POTENTIAL FOR A FAIR WX DAY AS SUBSIDENCE BEHIND THE EXITING LOW ALONG WITH HIGH PRES TO THE NORTH MAY HOLD MOST SHOWERS SOUTH AND WEST OF THE REGION. SAT...INCREASING CHC FOR SHOWERS AND TSTMS WITH THE APPROACH OF THE NEXT LOW WITH MAX CHANCES DURG THE AFTN AND EVE. SUNDAY...POTENTIAL FOR A FAIR WX DAY AS SUBSIDENCE BEHIND THE EXITING LOW PASSES ACROSS THE REGION. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/...
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VFR THROUGH THE TAF PERIOD AS HIGH PRESSURE BUILDS TONIGHT. LOW PRESSURE AND A WARM FRONT APPROACH TUESDAY. W/SW WIND FLOW LIGHTENS TONIGHT AS IT BACKS TO THE SSW-SW. S/SE WINDS INCREASE TUE MORNING BECOMING 9-15 KT IN THE AFTERNOON. THERE IS A CHANCE FOR SHRA AND ISO TSRA TOMORROW AFTERNOON...MAINLY WEST OF THE NYC METRO. .OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY... .TUESDAY NIGHT-SATURDAY...MVFR OR LOWER POSSIBLE AT TIMES THROUGH THE PERIOD IN SHRA AND POSSIBLE TSRA.
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&& .MARINE... SEAS REMAIN UP AROUND 5 FT AT 44017...SO WILL CONTINUE SMALL CRAFT ADVISORY FOR ANZ350 UNTIL 2 AM. SUB SCA CONDITIONS WITH A WEAK PRESSURE GRADIENT EXPECTED TUE INTO WED. NON OCEAN WATERS STAY BELOW SCA. WED NIGHT THRU THU MORNING...SEAS WILL GRADUALLY SUBSIDE BELOW SMALL CRAFT ADVISORY LVLS OF 5 FT BY THU AFTN. THU AFTN THRU SATURDAY...CHANCE OF TSTMS MAINLY DURING THU AND SAT AFTN AND EVENINGS WITH THE APPROACH OF LOW PRES SYSTEMS MOVING EAST ALONG A NEARLY STATIONARY FRONT JUST SOUTH OF THE COASTAL WATERS. WINDS AND SEAS ARE FORECAST TO REMAIN BELOW SMALL CRAFT ADVISORY LVLS OUTSIDE OF TSTMS. && .HYDROLOGY... NO WIDESPREAD SIGNIFICANT RAINFALL IS EXPECTED THROUGH TUE. TUE NIGHT THROUGH WED AFTN...PW VALUES 1.5 TO 1.75 INCHES WILL ENABLE ANY SHOWERS OR THUNDERSTORMS TO PRODUCE LOCALLY HEAVY RAIN. THE FORECAST BASIN AVG OF RAIN IS AROUND A HALF INCH BUT RAIN AMOUNTS COULD BE HIGHER LOCALLY UP TO 1 INCH APPROXIMATELY...POSSIBLY HIGHER. THIS COULD CAUSE AT LEAST MINOR URBAN/POOR DRAINAGE FLOODING...AND GIVEN EXPECTED ANTECEDENT CONDITIONS...POSSIBLY LOCALIZED FLASH FLOODING. THU AFTN THRU EVE AND SAT AFTN THRU EVE...AS LOW PRES SYSTEMS MOVE EAST ALONG A COLD FRONT...THERE IS A CHC OF 1/2-3/4- INCH RAIN WITH ISOLATED HIGHER AMOUNTS ASSOCIATED WITH HEAVIER SHOWERS AND TSTMS. MINOR URBAN FLOODING IS POSSIBLE. THERE IS A LOW PROB OF FLASH FLOODING. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR ANZ350. && $$ SYNOPSIS...GC/JM NEAR TERM...MPS SHORT TERM...JM LONG TERM...GC AVIATION...DS MARINE...GC/JM/MPS HYDROLOGY...GC/JM

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