Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 310246 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1046 PM EDT SAT AUG 30 2014 .SYNOPSIS... HIGH PRESSURE MOVES WELL TO THE EAST THROUGH SUNDAY. LOW PRESSURE TRACKS ACROSS THE GREAT LAKES AND INTO EASTERN CANADA...SENDING A LOW PRESSURE TROUGH ACROSS THE AREA LATE SUNDAY. THIS TROUGH WEAKENS AND EVENTUALLY DISSIPATES WITHIN THE REGION ON MONDAY. THIS WILL LEAVE BEHIND A WEAK PRESSURE GRADIENT. A COLD FRONT MOVES THROUGH TUESDAY NIGHT WITH HIGH PRESSURE THEN BUILDING IN FROM THE SOUTH AND WEST THROUGH THURSDAY. THE HIGH MOVES OFFSHORE FRIDAY WITH ANOTHER COLD FRONT APPROACHING INTO THE BEGINNING OF NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... ALOFT...LARGE RIDGE REMAINS ANCHORED SOUTHEAST OF THE REGION AS A TROUGH MOVES ACROSS THE GREAT LAKES REGION TONIGHT. SFC HIGH PRESSURE SITS SOUTHEAST OF THE REGION TONIGHT. PLENTY OF CLOUDS...WARM AND INCREASINGLY MUGGY CONDITIONS ARE FORECAST OVERNIGHT. DEW POINT INCREASE PER MOS AS SOUTH FLOW PERSISTS. LOW TEMPS IN THE 60S PER MOS BLEND FOLLOWED. HIGH RES MODELS SIGNALLING POTENTIAL LATE TONIGHT INTO EARLY SUNDAY MORNING FOR AN ISOLATED SHOWER WITH THETA-E ADVECTION AND A WEAK VORT MOVING THROUGH. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... DEEP SOUTHWEST FLOW THROUGH THIS TIME FRAME AS SHORTWAVE MOVES WELL TO THE NORTH...WITH RIDGE ANCHORED OVER THE WESTERN ATLANTIC. WARM AND MUGGY CONDITIONS WILL PREVAIL. PLENTY OF CLOUDS EXPECTED...ALONG WITH AN INCREASING CHANCE FOR SHOWERS/TSTMS. MODERATE INSTABILITY IS EXPECTED BY AFTERNOON SUNDAY...AND PRECIPITABLE WATERS INCREASE TO 2 INCHES...OR CLOSE TO 200 PERCENT ABOVE NORMAL LATE IN THE DAY AND INTO THE EVENING. MARGINAL TO MODERATE SHEAR IS PRESENT...WITH KI RIGHT AROUND 35C. EXPECT SCATTERED TO NUMEROUS...ALTHOUGH WILL KEEP PROBABILITY WORDING...SHOWERS AND TSTMS. SOME OF WHICH WILL PRODUCE HEAVY DOWNPOURS. BEST TIMING IS LATE AFTERNOON WESTERN ZONES...AND THROUGH THE EVENING/OVERNIGHT CSTL AND ERN ZONES. MODELS CONTINUE TO VARY WITH REGARD TO HEAVIER SHOWER/TSTM LOCATION...DUE TO THE SCATTERED NATURE OF THE ACTIVITY AND VARYING PLACEMENTS OF EMBEDDED MID LEVEL SHORTWAVES. SFC TROUGH APPROACHING TO THE WEST SHOULD TRIGGER ACTIVITY. AFTER COLLAB WITH SURROUNDING OFFICES...WILL NOT ISSUE A FLASH FLOOD WATCH AT THIS TIME. THE THREAT WILL BE URBAN...WITH PERHAPS FLASHIER STREAMS SUSCEPTIBLE TO FLASH FLOODING. OTHERWISE...COUNTY GUIDANCE LIKELY TOO HIGH OUTSIDE OF METRO. WARM TEMPS IN THE 80S SUNDAY...WITH WARM UPPER 60S TO 70S SUNDAY NIGHT LOWS. FOLLOWED A MOS BLEND...WHICH INCLUDED ECS NUMBERS. A MODERATE RISK OF RIP CURRENTS IS EXPECTED FOR THE FIRST HALF OF THE DAY SUNDAY...BUT THIS MAY INCREASE TO HIGH BY LATE IN THE DAY WITH INCREASING SOUTHERLY WINDS AND RESULTANT WINDS WAVES...INTERACTING WITH A BACKGROUND LONG PERIOD SE SWELL. && .LONG TERM /MONDAY THROUGH SATURDAY/... THE DOMINANT PATTERN IN THE LONG TERM IS THAT OF RIDGING ON AVERAGE. ON A LARGE SCALE...AN UPPER LEVEL RIDGE IS APPARENT ON THE MODEL HEIGHT FIELDS ALOFT FROM QUEBEC TO THE MID-ATLANTIC. A RELATIVELY STRONGER UPPER LEVEL TROUGH PASSES NORTH OF THE REGION LATE TUESDAY INTO EARLY WEDNESDAY WITH SOME MORE HEIGHT FALLS AND A TRANSITION TO ZONAL FLOW. RIDGING RESUMES THEREAFTER WITH THE LARGE RIDGE ACROSS THE SOUTHERN U.S. PUSHING NORTH FROM WEDNESDAY THROUGH FRIDAY. AT THE SURFACE...A SURFACE TROUGH MOVING IN FROM THE WEST DISSIPATES WITHIN THE REGION WITHOUT MUCH UPPER LEVEL SUPPORT ON MONDAY. A WEAK PRESSURE GRADIENT IS LEFT IN ITS PLACE WITHOUT A STRONG PRESENCE OF HIGH PRESSURE. THE JET STREAM WILL BE LIFTING NORTH AWAY FROM THE REGION HELPING EXPLAIN THE LACK OF SUPPORT ALOFT. THE JET PUSHES BACK SOUTH TUESDAY NIGHT INTO EARLY WEDNESDAY...SO THIS WILL HELP PUSH A COLD FRONT THROUGH THE REGION. THIS WILL TRANSITION WINDS TO MORE OF A NORTHERLY FLOW FOR WEDNESDAY. THE FLOW WEAKENS THURSDAY...ALLOWING FOR SEA BREEZES TO DEVELOP AS HIGH PRESSURE BUILDS IN FROM THE SOUTH AND WEST. THE HIGH MOVES OFFSHORE FRIDAY INTO THE NEXT WEEKEND. ANOTHER COLD FRONT APPROACHES INTO THE BEGINNING OF NEXT WEEKEND. OUTSIDE OF WEDNESDAY...A GENERAL SOUTH TO SOUTHWEST FLOW DOMINATES NEXT WEEK. THIS WILL RESULT IN TEMPERATURES WELL ABOVE SEASONAL AVERAGES FOR THIS TIME OF YEAR. THE JET STREAM OVERALL KEEPS TO THE NORTH OF THE REGION. TEMPERATURES WILL BE GENERALLY 5-10 DEGREES ABOVE NORMAL MONDAY THROUGH WEDNESDAY AND A FEW DEGREES ABOVE NORMAL WEDNESDAY NIGHT THROUGH SATURDAY. IN TERMS OF WEATHER...HIGHEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ON MONDAY WITH THE INSTABILITY AND REMNANT FRONTAL BOUNDARY ACROSS THE REGION. CHANCES DECREASING BY LATE IN THE DAY AND INTO MONDAY NIGHT. ESTIMATING THESE TO BE MORE OF THE PULSE VARIETY WITH THE LACK OF UPPER LEVEL SUPPORT. BULK SHEAR 0-6KM MOSTLY 20-25 KT WITH CAPE BEING THE GREATER DRIVER FOR CONVECTION. ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS FROM NORTHWEST TO SOUTHEAST TUESDAY INTO TUESDAY NIGHT WITH A LITTLE MORE SHEAR TO WORK WITH. MAINLY DRY THEREAFTER WITH A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS TOWARDS END OF THE WORK WEEK INTO THE NEXT WEEKEND WITH NEXT FRONT APPROACHING. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... HIGH PRES OFF THE NEW ENGLAND COAST WILL MOVE OUT TO SEA OVERNIGHT AS A TROUGH OF LOW PRES APPROACHES FROM THE WEST LATE SUNDAY. VFR CIGS THIS EVENING LIKELY TO GRADUALLY LOWER THROUGH THE OVERNIGHT...WITH LOW MVFR/LOCALLY IFR CIGS LIKELY LATE TONIGHT/SUN AM. HEATING SHOULD RAISE CIGS TO VFR IN THE LATE MORNING/EARLY AFTN. ISOLATED SHRA/TSRA POSSIBLE ALONG SEABREEZE BOUNDARIES SUN AFTERNOON. OTHERWISE...INCREASING CHANCE FOR SHRA/TSTMS LATE AFTN/EVE MAINLY FROM CITY TERMINALS AND POINTS N/W AS TROUGH APPROACHES. .OUTLOOK FOR 00Z MON THROUGH THU... .SUN NIGHT-MON...NUMEROUS SHRA/EMBEDDED TSTMS AND OCNL MVFR TRANSLATING EASTWARD ACROSS TERMINALS SUN NIGHT THROUGH MON MORNING. ADDITIONAL SCT SHRA/TSRA POSSIBLE MON AFT/EVE. MVFR STATUS/FOG POSSIBLE LATE MON NIGHT. .TUE...SCT AFT/EVE SHRA/TSRA POSSIBLE. .WED-THU...MAINLY VFR. && .MARINE... SOUTHERLY WINDS PERSISTS TONIGHT AS HIGH PRESSURE DRIFTS FURTHER TO THE EAST. THE SOUTHERLY WINDS INCREASE AHEAD OF A SURFACE TROUGH LATER SUNDAY INTO SUNDAY EVENING. EXPECT WINDS TO REMAIN JUST BELOW 25 KTS ON THE WATERS...SO WILL NOT ISSUE A SCA AT THIS TIME PER SURROUNDING OFFICE COLLAB. SEAS BUILD IN RESPONSE TO THESE INCREASING WINDS...AND MAY COME CLOSE TO 5 FEET OVER THE OCEAN WATERS LATE SUNDAY AND INTO SUNDAY NIGHT. OVERALL...THE PRESSURE GRADIENT REMAINS WEAK IN THE LONG TERM PERIOD OF MONDAY THROUGH THURSDAY. SEAS WILL BE ON A DOWNWARD TREND EARLY MONDAY WITH A COLD FRONT DISSIPATING WITHIN THE REGION. CONDITIONS ARE EXPECTED TO REMAIN BELOW SCA ON THE WATERS THROUGH THE LONG TERM PERIOD. && .HYDROLOGY... DEEP MOISTURE IN PLACE WITH TROF APPROACHING SUNDAY AND INTO THE REGION SUNDAY NIGHT...SO ANY SHOWERS AND THUNDERSTORMS WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY DOWNPOURS. LOCALIZED FLOODING THREAT WILL REMAIN WHICH WOULD VARY FROM MINOR AND POOR DRAINAGE TO POSSIBLY FLASH FLOODING. HEAVY RAIN POTENTIAL WITH ANY SHOWERS OR THUNDERSTORMS WILL REMAIN AS PRECIPITABLE WATERS REMAIN AROUND 2 INCHES MONDAY. THIS WILL POSE A FLOODING THREAT VARYING FROM POSSIBLE MINOR AND POOR DRAINAGE FLOODING TO SOME POSSIBLE FLASH FLOODING. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JM/PW NEAR TERM...JM/PW SHORT TERM...PW LONG TERM...JM AVIATION...NV MARINE...JM/PW HYDROLOGY...JM/PW

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