Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Text Only | 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 110757 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 357 AM EDT FRI JUL 11 2014 .SYNOPSIS... HIGH PRESSURE REMAINS OVER THE AREA TODAY AND SATURDAY...THEN WEAKENS AND MOVES FARTHER OFFSHORE SUNDAY. MEANWHILE...A COLD FRONT APPROACHES FROM THE NORTHWEST...SLOWLY MOVING IN MONDAY INTO MONDAY NIGHT AND THEN STALLING WITHIN THE REGION THROUGH EARLY NEXT WEEK. SMALL WEAK LOWS FORM ALONG THE FRONT WITH ONE EVENTUALLY PUSHING THE FRONT EAST OF THE REGION BY NEXT WEDNESDAY NIGHT INTO NEXT THURSDAY WITH HIGH PRESSURE FOLLOWING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH PRESSURE WILL BE OVER THE REGION TODAY WITH STATIONARY FRONT JUST OFF TO OUR SOUTH. CLOUDS WILL TRAVEL ALONG THIS BOUNDARY WITH A PARTLY TO MOSTLY CLOUDY START EAST OF THE CITY...BUT ANY RAINFALL SHOULD REMAIN OFFSHORE. BY NOON...PARTLY CLOUDY/MOSTLY SUNNY CONDITIONS ACROSS THE ENTIRE AREA. A SHORTWAVE AND WEAKENING UPPER ALSO PASS THROUGH TODAY...BUT IT LOOKS LIKE MOISTURE WILL BE MORE LIMITED AS COMPARED TO YESTERDAY. IN ADDITION...A LIGHT ONSHORE FLOW WILL ALLOW FOR SEA BREEZES TO DEVELOP AND STABILIZE MUCH OF THE AREA...SO NOT EXPECTING SHOWERS TO DEVELOP HERE IN RESPONSE TO THE LIFT AND CYCLONIC FLOW ALOFT. A MAV/NAM MOS BLEND LOOKED GOOD FOR HIGHS...WHICH WILL BE NEAR NORMALS. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... THE SYNOPTIC PATTERN DOESN`T CHANGE ALL THAT MUCH DURING THIS PERIOD. HIGH PRESSURE WILL HOWEVER DRIFT FARTHER OUT TO SEA WITH MORE OF A RETURN S TO SW FLOW AND A LITTLE MORE HUMID AIRMASS. MOISTURE STILL APPEARS TO BE LACKING FOR ANY MID LEVEL SHORTWAVES TO TRIGGER SHOWERS. WILL CONTINUE WITH A DRY FORECAST. MAV/NAM MOS NUMBERS FOR HIGHS AND LOWS WERE SIMILAR AGAIN...AND A BLEND WAS USED. && .LONG TERM /SUNDAY THROUGH THURSDAY/... FOR THE TIME PERIOD OF SUNDAY THROUGH THURSDAY...GENERALLY THERE WILL BE A BUILDING RIDGE TO THE WESTERN U.S. AND A DEEP CUTOFF LOW IN MANITOBA/ONTARIO. MULTIPLE LOBES OF VORTICITY MAXIMA WILL BE WITHIN THE CUTOFF LOW. ONE SPOKE ROTATES INTO THE WESTERN GREAT LAKES SUNDAY NIGHT...IMPINGING ON THE WESTERN U.S. RIDGE. THE MAIN CUTOFF LOW WILL EVENTUALLY TRAVERSE INTO THE EASTERN GREAT LAKES...STARTING TO SHIFT NORTH INTO QUEBEC BY MIDWEEK. ACROSS THE LOCAL AREA...ZONAL MID LEVEL FLOW SUNDAY BECOMES PROGRESSIVELY MORE AND MORE SOUTHWEST INTO NEXT WEEK...IN RESPONSE TO AN AMPLIFYING TROUGH TO THE WEST OF THE REGION. THE ASSOCIATED UPPER LEVEL JET WILL STILL BE NORTH OF AREA SUNDAY WITH A ZONAL FLOW. THIS JET WILL SLOWLY PUSH MORE SOUTH AND EAST WITH TIME GOING INTO NEXT WEEK...EVENTUALLY BECOMING A STRONG MERIDIONAL JET BY MID NEXT WEEK AS IT MOVES INTO THE LOCAL REGION. THIS JET AND ASSOCIATED TROUGH AXIS MOVE ACROSS LATE NEXT THURSDAY INTO NEXT THURSDAY NIGHT. AT SURFACE...SUNDAY FEATURES WEAKENING HIGH PRESSURE TRANSLATING FARTHER OFFSHORE. A PRE-FRONTAL TROUGH AHEAD OF THE COLD FRONT DEVELOPS AND MOVES IN FROM THE WEST...BECOMING A FOCUS FOR SHOWER AND THUNDERSTORM ACTIVITY. FOR SUNDAY NIGHT...THE PARENT LOW DEEPENS WITHIN QUEBEC WITH ASSOCIATED COLD FRONT APPROACHING FROM NORTHWEST. THE FRONT MOVES IN ON MONDAY INTO MONDAY NIGHT BUT THEREAFTER PARENT LOW IN QUEBEC MOVES FARTHER AWAY AND FILLS IN. THE RESULT WILL BE A LACK OF STEERING FLOW AND A STAGNATION AS WELL AS WEAKENING OF THE FRONT. THE WEAK FRONT LINGERS WITHIN THE REGION THROUGH MID WEEK. THE SCENARIO IS ILLUSTRATIVE OF ROUNDS OF SHOWERS AND THUNDERSTORMS FROM SUNDAY NIGHT THROUGH WEDNESDAY AS WEAK LOWS MOVE ALONG THE STALLED FRONT. LESS FREQUENT SUNDAY NIGHT BUT BECOMING MORE FREQUENT MONDAY NIGHT THROUGH WEDNESDAY WHEN MOISTURE TRANSPORT INCREASING WITH THE INCREASED MERIDIONAL FLOW. THE LAYER PRECIPITABLE WATERS INCREASE RAPIDLY SUNDAY AND REMAIN RELATIVELY NEAR 2 INCHES THROUGH MIDWEEK. THIS WILL ALLOW FOR TORRENTIAL DOWNPOURS WITH SOME SHOWERS AND THUNDERSTORMS. NEXT WEDNESDAY NIGHT INTO NEXT THURSDAY...THE LAST LOW WILL HELP PUSH THE FRONT FINALLY EAST OF THE REGION. IN ITS PLACE...HIGH PRESSURE STARTS TO BUILD IN FROM THE WEST...WITH DRY WEATHER RETURNING AS MID AND UPPER LEVEL TROUGHS BEGIN TO LIFT NORTH AND BECOME LESS AMPLIFIED. THERE IS STILL A LOT OF UNCERTAINTY AND FACTORS SUCH AS THE SPOKES OF VORTICITY ASSOCIATED WITH THE CUTOFF LOW AND ASSOCIATED UPPER LEVEL JET THAT COULD RESULT IN TIMING DIFFERENCES OF SHOWERS AND THUNDERSTORMS WITH SUBSEQUENT FORECASTS. THEREFORE...MUCH OF THE TIMEFRAME HAS CHANCE WORDING BUT THE HIGHER CHANCES...NEAR 50-55 PERCENT...REPRESENT A TIME PERIOD WHERE THE CONVECTION IS FORECAST TO BE MORE FREQUENT WITH RELATIVELY HIGHER COVERAGE EXPECTED. HIGH TEMPERATURES FORECAST ARE NEAR TO SLIGHTLY ABOVE NORMAL ON AVERAGE ACROSS THE REGION SUNDAY THROUGH TUESDAY AND THEN SLIGHTLY BELOW NORMAL ON AVERAGE WEDNESDAY AND THURSDAY NEXT WEEK. LOW TEMPERATURES AT NIGHT ARE FORECAST TO BE SLIGHTLY ABOVE NORMAL SUNDAY NIGHT THROUGH TUESDAY NIGHT AND TREND TO SLIGHTLY COOLER THAN NORMAL FOR NIGHTS THEREAFTER. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... HIGH PRESSURE BUILDS OVER THE AREA INTO TONIGHT. HIGH CONFIDENCE IN VFR THROUGH THE TAF PERIOD. IT APPEARS ANY CONVECTION SHOULD STAY TO THE SE AND NW OF THE AREA THROUGH THE TAF PERIOD. LIGHT AND VARIABLE WINDS BECOME NE AT UNDER 10 KT EARLY THIS MORNING. A SEA BREEZE DEVELOPS AROUND MIDDAY THEN SLOWLY PUSHES INLAND...REACHING ALL TERMINALS BUT KSWF BY LATE AFTERNOON. WINDS BECOME LIGHT AND VARIABLE AGAIN BY EARLY THIS EVENING. .OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY... .LATE FRIDAY NIGHT-SUNDAY MORNING...VFR. .SUNDAY AFTERNOON-TUESDAY...SCT TO POSSIBLY NUMEROUS SHRA/TSTMS. STRONGER TSTMS DURING THIS TIME FRAME COULD PRODUCE PERIODS OF MVFR OR LOWER CONDITIONS...LOCALLY HEAVY RAINFALL AND GUSTY WINDS. && .MARINE... HIGH PRESSURE WILL RESULT IN WINDS AND SEAS REMAINING BELOW SCA LEVELS THROUGH SATURDAY NIGHT. INITIALLY SUB SCA CONDITIONS WITH HIGH PRESSURE OFFSHORE WILL TRANSITION TO A PROLONGED SOUTHERLY FETCH AS HIGH PRESSURE WEAKENS AND SHIFTS FARTHER OFFSHORE. THERE WILL BE SIMULTANEOUSLY A COLD FRONT SLOWLY APPROACHING FROM THE WEST. SCA GUSTS NEAR 25 KT ARE FORECAST FOR PORTIONS OF THE OCEAN SUNDAY AFTERNOON AND SUNDAY NIGHT AND THIS WILL EVENTUALLY BUILD UP SEAS TO 5 FT SUNDAY NIGHT INTO MONDAY. THE SEAS WILL FURTHER INCREASE 5-7 FT MONDAY NIGHT THROUGH TUESDAY...KEEPING SCA CRITERIA CONDITIONS WITH THE SOUTHERLY FETCH. NON-OCEAN WATERS ARE EXPECTED TO STAY BELOW SCA SUNDAY INTO NEXT WEEK. && .HYDROLOGY... NO WIDESPREAD SIGNIFICANT HYDROLOGIC ISSUES EXPECTED THROUGH SUNDAY MORNING. THERE IS THE POTENTIAL FOR SIGNIFICANT RAINFALL - WIDESPREAD 1/2 INCH OR MORE - FROM LATE SUNDAY INTO WEDNESDAY AS PRECIPITABLE WATERS COULD REACH AROUND 2 INCHES FOR AN EXTENDED PERIOD OF TIME - FAVORING AT LEAST LOCALLY HEAVY RAINFALL. AT THIS TIME THERE IS TOO MUCH UNCERTAINTY TO SPECIFY EXACT AMOUNTS OR SPECIFIC THREATS...OTHER THAN TO NOTE THE POTENTIAL FOR MINOR URBAN/POOR DRAINAGE FLOODING AND POSSIBLY LOCALIZED FLASH FLOODING IN AREAS THAT EXPERIENCE LOCALLY HEAVY RAINFALL. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JC/JM NEAR TERM...JC SHORT TERM...JC LONG TERM...JM AVIATION...MALOIT MARINE...JC/JM HYDROLOGY...JC/JM

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