Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 280513 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 113 AM EDT MON JUL 28 2014 .SYNOPSIS... DEVELOPING SURFACE LOW PRESSURE ACROSS NEW YORK WILL TRACK INTO VERMONT ON MONDAY...RESULTING IN A WIDESPREAD MODERATE RAINFALL. A FEW EMBEDDED THUNDERSTORMS WITH LOCALIZED GUSTY WINDS WILL BE POSSIBLE OVER EASTERN VERMONT ON MONDAY AFTERNOON. TEMPERATURES WILL BE SEVERAL DEGREES BELOW NORMAL TO START THE WORK WEEK...WITH SOME SHOWERS LINGERING INTO TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 113 AM EDT SUNDAY...WITH LIGHT WINDS AND WET GROUND FROM TODAY`S RAINFALL...I`VE ADDED PATCHY FOG INTO THE FORECAST THROUGH THE NEXT COUPLE OF HOURS FOR A LARGE PORTION OF THE NORTH COUNTRY. I`VE ALSO ADJUSTED POPS/WX AFTER MIDNIGHT TO BETTER SHOW TIMING OF AREA OF MODERATE RAIN/EMBEDDED THUNDERSTORMS NOW IMPACTING SOUTH- CENTRAL NEW YORK STATE. HI-RES CONVECTION-ALLOWING MODEL REFLECTIVITY PROGS AND SIMPLE EXTRAPOLATION PUTS THE LEADING EDGE OF THIS AREA OF MODERATE RAIN FROM THE SOUTHERN ST. LAWRENCE VALLEY - ADIRONDACKS - SOUTHERN VT AREA AROUND 08-09Z. SHOWN HIGH POPS (LIKELY TO CATEGORICAL) AND CONTINUING TO TAPER UPWARD THROUGH 12Z. INSTABILITY IS LIMITED BUT THUNDER`S ALREADY ONGOING ACROSS CENTRAL NEW YORK...IN ZONE OF MID-/UPPER-LEVEL DIFFLUENCE AND IN THE POLEWARD EXIT REGION OF MID-LEVEL JET STREAK APPROACHING WESTERN PA. THAT SYNOPTIC-SCALE LIFT WILL OFFSET THE SCANT INSTABILITY AND KEEP THUNDER GOING AS BAND OF MODERATE RAIN SPREADS NORTH. SO I`VE KEPT CHANCE THUNDER TIED TO THE LIKELY/CATEGORICAL POPS. TEMPS LOOK REASONABLY GOOD WITH ONLY ADJUSTMENT HERE TO MATCH CURRENT OBSERVATIONS. PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 1001 PM EDT SUNDAY FOLLOWS... AREAL COVERAGE OF SHOWERS CONTINUES TO DECREASE NOTICEABLY TONIGHT. SHOULD ONLY BE SOME ISOLATED SHOWERS THROUGH THE EARLY MORNING HOURS...THEN THE FOCUS TURNS TO THE LARGE AREA OF PRECIPITATION TO OUR SOUTHWEST. POTENT STORM SYSTEM COMING OUT OF THE EASTERN GREAT LAKES TONIGHT WILL CONTINUE TO ENHANCE PRECIPITATION DEVELOPMENT ACROSS WESTERN AND CENTRAL NEW YORK AFTER MIDNIGHT...AS WELL AS IN PENNSYLVANIA...WITH THE FLOW GRADUALLY BACKING AND ALLOWING ALL OF IT TO MOVE UP INTO OUR AREA TOWARD MORNING. GOING FORECAST HAS THIS COVERED WELL AND ONLY TWEAKED GRIDS TO MATCH CURRENT CONDITIONS BEFORE TRANSITIONING TO THE INCREASING PRECIPITATION CHANCES TOWARD MORNING. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... AS OF 340 PM EDT SUNDAY...POTENT SYSTEM WL IMPACT OUR CWA ON MONDAY AND MONDAY NIGHT...WITH A WIDESPREAD MODERATE TO LOCALIZED HEAVY RAINFALL EVENT. IN ADDITION...STILL WATCHING FOR THE POTENTIAL OF STRONG STORMS ACRS OUR EASTERN/SOUTHERN CWA ON MONDAY AFTN...AS PART OF THIS AREA GETS INTO THE WARM SECTOR. TOTAL RAINFALL AMOUNTS WL GENERAL BE BTWN 1 AND 2 INCHES BY TUESDAY WITH THE HEAVIEST AMOUNTS FROM THE DACKS TO CPV TO NORTHERN/CENTRAL VT MTNS. NOT ANTICIPATING ANY MAJOR HYDRO ISSUES...BUT COULD SEE SOME MINOR POOR DRAINAGE URBAN FLOODING IN THE HIGHER RAINFALL RATES ON MONDAY. WATER VAPOR SHOWS POTENT 5H VORT ACRS THE WESTERN GREAT LAKES...QUICKLY MOVING SE TWD THE OHIO VALLEY ATTM...WITH SOME LIGHTNING ACTIVITY ALREADY NOTED UNDER THE 5H CIRCULATION. THIS CONVECTIVE ACTIVITY AND UPSTREAM ACTION TODAY...MAKES FOR A TRICKY SFC LOW TRACK HEADING INTO MONDAY...ALONG WITH THE EXACT PLACEMENT OF A STRONG NW TO SE THERMAL BOUNDARY. AS VIGOROUS 5H VORT ROUNDS MID/UPPER LVL TROF...SYSTEM WL BECOME NEGATIVELY TILTED BY 18Z WEDS...WITH SFC LOW PRES TRACKING FROM NEAR KBGM AT 12Z MONDAY TO NORTHERN VT BY 00Z TUES. THIS TRACK PLACES OUR WESTERN CWA ON THE COOL SIDE...WHILE PARTS OF THE CENTRAL/EASTERN CWA WL BE IN THE WARM SECTOR WITH THE POTENTIAL FOR CONVECTION ON MONDAY AFTN. THINKING INITIAL SURGE OF MID WAA LIFT/MOISTURE WL DEVELOP ACRS RUTLAND/WINDSOR COUNTIES AROUND 12Z MONDAY AND LIFT INTO CENTRAL/NORTHERN VT 14Z...BEFORE BEING NORTH OF OUR CWA BY 16Z MONDAY. THIS LIFT/MOISTURE WL RESULT IN A 2 TO 4 HOUR WINDOW OF MODERATE RAINFALL WITH EMBEDDED STORMS. HOWEVER...AS SOME BREAKS DEVELOP IN THE WARM SECTOR ON MONDAY AFTN...SFC INSTABILITY IS EXPECTED TO INCREASE BTWN 800 AND 1200 J/KG...WITH 0 TO 6 KM SHEAR AROUND 30 KNOTS. THINKING SCATTERED STORMS WL DEVELOP ACRS OUR EXTREME EASTERN CWA...WITH A FEW STRONGER STORMS CAPABLE OF GUSTY WINDS AND SMALL HAIL POSSIBLE....ESPECIALLY GIVEN THE VERY STRONG DYNAMICS ALOFT. THE SYSTEM AND ASSOCIATED CONVECTION ON MONDAY WL BE DRIVEN BY THE STRONG DYNAMICS AND NOT SO MUCH THE INSTABILITY. BOTH THE GFS/NAM 850 TO 500MB RH PROGS SHOW A NICE WELL DEFINED DRY SLOT DEVELOPING ACRS OUR EASTERN CWA AT 18Z MONDAY...WHILE A BAND OF DEEP RH ASSOCIATED WITH BACKSIDE DEFORMATION EXTENDS FROM NORTHERN/CENTRAL NY INTO NORTHERN VT. THIS MOISTURE COMBINED WITH FAVORABLE NORTHWEST LOW LEVEL UPSLOPE FLOW AND ASSOCIATED LIFT FROM THERMAL DRIVEN MID LVL TROWAL FEATURE WL HELP TO PRODUCE ADDITIONAL MODERATE RAINFALL ACRS THE DACKS INTO THE CPV AND MOST OF CENTRAL/NORTHERN VT ON MONDAY AFTN/EVENING. GIVEN THE TRACK OF THE CLOSED 85H AND 7H CIRCULATIONS...AND SFC LOW...EXPECT BACKSIDE DEFORMATION PRECIP TO LINGER OVERNIGHT MONDAY...BEFORE TAPERING OFF ON TUES MORNING. THINKING TOTAL QPF WL RANGE BTWN 0.25 AN 0.75" SLV/WESTERN DACKS TO 0.75 TO 1.75" EASTERN DACKS/CPV AND NORTHERN VT....WITH AMOUNTS BTWN 0.50 AND 1.0" ACRS SOUTHERN/CENTRAL VT...WITH SOME LOCALIZED HIGHER AMOUNTS AROUND 2.0" POSSIBLE DUE TO CONVECTION AND TRRN. EXPECTING SOME SHARP RISES ON SMALLER STREAMS/RIVERS...BUT GIVEN RECENT DRY SPELL NO MAJOR HYDRO ISSUES ANTICIPATED ATTM. VERY INTERESTING TEMP PROFILE ON MONDAY WITH NORTHERLY WINDS DOWN THE CPV/SLV AND LOW LEVEL CAA/CLOUDS...TEMPS WL STRUGGLE IN THE UPPER 50S DACKS TO L/M60S CPV/SLV AND MID 70S LWR CT RIVER VALLEY NEAR VSF. THE MTNS OF VT WL HOLD IN THE U50S TO LOWER 60S ON MONDAY WITH LOWER 70S POSSIBLE IN THE NEK VALLEYS. TUESDAY-TUESDAY NIGHT...MID/UPPER LVL CLOSED CIRCULATION LIFTS INTO EASTERN CANADA WITH CYCLONIC NW FLOW ACRS OUR CWA. BEST 850 TO 500MB MOISTURE LIFTS NORTH OF OUR CWA BY 12Z TUES...BUT GIVEN AMOUNT OF ENERGY IN THE FLOW ALOFT AND SOME SFC HEATING ON TUES AFTN...CANNOT RULE OUT THE POTENTIAL FOR SOME SCATTERED SHOWERS TO DEVELOP IN THE AFTN...ESPECIALLY WITH PLENTY OF LEFTOVER BL MOISTURE. THIS ACTIVITY WL DECREASE BY TUES EVENING...WITH CHILLY NORTHWEST WINDS. TUES/TUES NIGHT WL FEEL A BIT LIKE FALL WITH TEMPS ONLY WARMING INTO THE U50S/L60S MTNS TO NEAR 70F WARMER VALLEYS...ASSOCIATED WITH PROGGED 85H TEMPS ONLY BTWN 6-8C. WINDS/CLOUDS AND PLENTY OF LEFTOVER BL RH WL KEEP TEMPS FROM COMPLETELY BOTTOMING OUT ON TUES NIGHT...THINKING MAINLY 40S MTNS TO 50S VALLEYS. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 315 PM EDT SUNDAY...MODELS REMAIN IN GOOD AGREEMENT INDICATING DEEP LARGE SCALE TROUGH OVER THE EASTERN CONUS WITH RIDGE OVER THE INTER-MOUNTAIN WEST THROUGH MUCH OF THE PERIOD...THOUGH TROUGH WEAKENS LATER IN THE PERIOD WITH SLOWLY RISING HEIGHTS. DESPITE THE PRESENCE OF LARGE UPPER TROUGH OVER THE REGION...EXPECT MUCH OF THE TIME TO BE DRY. SHORTWAVES MOVING THROUGH THE MEAN TROUGH DIFFICULT TO TIME THIS FAR OUT...BUT LATEST GUIDANCE SUGGESTS STRONGEST DISTURBANCE WILL MOVE ACROSS THE AREA THURSDAY. OTHERWISE...CHANCES FOR PRECIPITATION LARGELY DIURNALLY DRIVEN...WITH BEST CHANCES DURING THE AFTERNOON HOURS AND MAINLY DRY CONDITIONS ANTICIPATED EACH NIGHT AND EARLY MORNING. BELOW NORMAL TEMPS EXPECTED THROUGH MIDWEEK. 850 MB TEMPS PROGGED TO TO BE AROUND 10-11C WED/THU THEN MODERATE TO 12-13C BY THE WEEKEND. WITH PARTIAL SUN...THIS SUPPORTS VALLEY HIGHS IN THE MID TO UPPER 70S WED/THU AND AROUND 80 FOR THE REST OF THE PERIOD. EXPECT MINS IN THE 50S TO LOWER 60S. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... THROUGH 00Z TUESDAY...STILL LOOKING AT SCATTERED THUNDERSTORMS ACROSS THE AREA THROUGH ABOUT 03Z...WHICH COULD CREATE BRIEF PERIODS OF IFR AND LIFR CEILINGS AND VISIBILITIES. BEST CHANCES FOR THESE STORMS WILL BE AT KPBG...KBTV...KSLK...AND KMPV. SHOWER AND THUNDER CHANCES DECREASE SHARPLY AFTER 03Z AND VFR CONDITIONS DEVELOP. COULD BE SOME FG/BR LATER TONIGHT WITH A PERIOD OF CLEARING AND LIGHT WINDS EXPECTED...AS FRONTAL SYSTEM STALLS JUST TO THE NORTH. BETWEEN 09-12Z RAIN EXPECTED TO OVERSPREAD THE AREA AS LOW PRESSURE LIFTS NORTHEAST FROM PENNSYLVANIA LATER TONIGHT INTO CENTRAL NEW ENGLAND MONDAY AFTERNOON. EXPECT CONDITIONS TO LOWER TO MVFR AREA-WIDE WITH POSSIBLE IFR AT TIMES. THUNDER POSSIBLE AT VERMONT SITES. SOUTH/SOUTHWEST WINDS 5 TO 15 KNOTS THIS PM. SOME GUSTS TO 20 KNOTS POSSIBLE. LIGHT WINDS TONIGHT...THEN BECOMING NORTHERLY 5 TO 15 KTS DURING MONDAY. OUTLOOK 00Z MONDAY THROUGH FRIDAY... 00Z TUE - 12Z TUE...PERIODS OF MVFR IN RAIN AND ISOLATED THUNDERSTORMS. LOCAL IFR POSSIBLE IN HEAVIER RAIN. 12Z TUE - 12Z THU...TRENDING VFR. POSSIBLE IFR/LOWER VISIBILITY IN OVERNIGHT FOG/MIST MPV AND SLK. 12Z THU ONWARD...MAINLY VFR ALTHOUGH BRIEF PERIODS OF MVFR POSSIBLE IN SCATTERED SHOWERS. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...TABER NEAR TERM...EVENSON/LOCONTO SHORT TERM...TABER LONG TERM...RJS AVIATION...EVENSON

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