Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 241741 AFDBTV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1241 PM EST WED DEC 24 2014 .SYNOPSIS... ACTIVE WEATHER IS EXPECTED TODAY AND CHRISTMAS DAY WITH ABOVE NORMAL TEMPERATURES AND WIDESPREAD RAIN POTENTIALLY LEADING TO MINOR FLOODING ACROSS THE NORTH COUNTRY. AS THE RAIN ENDS EARLY CHRISTMAS MORNING...STRONG AND GUSTY SOUTHWEST TO WEST WINDS WILL DEVELOP OVER THE AREA WITH GUSTS IN THE 40 TO 60 MPH RANGE EXPECTED ACROSS NORTHERN NEW YORK...AND 30 TO 40 MPH ACROSS MUCH OF VERMONT. DRIER...LESS WINDY WEATHER RETURNS ON FRIDAY WITH TEMPERATURES REMAINING ABOVE NORMAL. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... AS OF 1223 PM EST WEDNESDAY...MINIMAL CHANGES TO FORECAST. TEMPS AND POPS TRACKING WELL WITH MOST READINGS IN THE UPPER 30S TO 40S. RADAR SHOWING ANOTHER ROUND OF RAIN MOVING NORTHEAST ACROSS ADIRONDACKS...EXPECT TO CONTINUE THROUGH THE AFTERNOON. RAIN IS WELL COVERED BY CATEGORICAL POPS AND NO CHANGES NEEDED. PREVIOUS DISCUSSION...FULL LATITUDE MID-LEVEL TROUGH ACROSS THE MISSISSIPPI RIVER VALLEY IS LEADING TO LONG FETCH OF GULF MOISTURE AND WARMER TEMPERATURES, WHICH WILL CONTINUE TO ADVECT NORTHWARD TOWARD THE NORTH COUNTRY TODAY. ASSOCIATED SURFACE LOW IS DEEPENING AS EXPECTED ACROSS THE TN VALLEY EARLY THIS MORNING...AND WILL TRACK GENERALLY NWD WELL WEST OF OUR AREA...REACHING THE DETROIT, MICHIGAN AREA BY 00Z THIS EVENING. HAVE SEEN OVERCAST SKIES LOCALLY WITH PERIODS OF DRIZZLE AND FOG OVER THE SNOWPACK EARLY THIS AM. REGIONAL MOSAIC RADAR IMAGERY SHOWS THE WIDESPREAD AREA OF RAINFALL MOVING NWD THRU WRN NY AND PA AT 0845Z...AND THIS STEADY RAIN WILL OVERSPREAD THE NORTH COUNTRY LATE THIS MORNING AND CONTINUE DURING THE AFTERNOON HOURS. PW VALUES INCREASE TO ABOUT 1.25" BY LATE AFTERNOON...AND WILL LIKELY SEE SOME PERIODS OF MODERATE RAINFALL. TEMPERATURES WILL ALSO SLOWLY CLIMB THRU THE LOW TO MID 40S, SO MUCH OF THE SNOW PACK WILL RIPEN AND ALONG WITH THE DEVELOPING RAINFALL. HAVE MAINTAINED THE FLOOD WATCH WITH EXPECTATIONS LARGELY UNCHANGED FROM PREVIOUS FORECASTS. PERIODS OF RAIN CONTINUE THROUGH TONIGHT BEFORE ENDING DURING THE PRE-DAWN HOURS FROM WEST TO EAST CHRISTMAS DAY. FOR STORM TOTAL RAINFALL...LOOKING AT 0.60-1.20"...RANGING FROM LOWER VALUES IN THE ST. LAWRENCE VALLEY TO HIGHER VALUES IN SERN VERMONT. TEMPERATURES GENERALLY STEADY IN THE LOW-MID 40S OVERNIGHT TONIGHT...THEN RISING JUST IN ADVANCE OF THE COLD FRONT...POTENTIALLY REACHING 50-54F IN THE CHAMPLAIN VALLEY...RUTLAND COUNTY...AND INTO PORTIONS OF CENTRAL VT. && .SHORT TERM /10 PM THIS EVENING THROUGH FRIDAY/... AS OF 337 AM EST WEDNESDAY...FLOOD WATCH REMAINS IN EFFECT THROUGH 7PM ON CHRISTMAS DAY. WE HAVE ALSO ISSUED A HIGH WIND WATCH FOR THE ST. LAWRENCE VALLEY AND A WIND ADVISORY FOR THE REMAINDER OF NRN NY VALID 6AM THRU 6PM EST ON CHRISTMAS DAY. SURFACE OCCLUDED FRONT SWEEPING THRU EARLY CHRISTMAS MORNING WILL ALLOW THE STEADIER RAIN TO EXIT EAST OF VT BY 12Z OR SO. LOW- LEVEL COLD ADVECTION AND STRONG P-GRADIENT SETS UP GUSTY SWLY WIND CONDITIONS IMMEDIATELY FOLLOWING FRONTAL PASSAGE. AT KMSS...BUFKIT SOUNDINGS SUGGESTS GUSTS TO 45 KTS ALREADY IN PLACE BY 12Z THURSDAY PER BOTH 00Z NAM/GFS...WITH GUSTS PEAKING NEAR 50-52KTS DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. GOOD CONSISTENCY BETWEEN MODELS AND RUN-TO-RUN WARRANTED WIND HIGHLIGHTS...WITH THE GUSTY SW WINDS CONTINUING UNTIL PBL STABILIZATION OCCURS TOWARD/AFTER SUNSET CHRISTMAS DAY. GRADIENT FLOW IS NOT QUITE AS STRONG ACROSS VT...BUT WILL LIKELY SEE WSW WIND GUSTS OF 25-35 KTS IN MOST SECTIONS. LOW-LEVEL MOIST SWLY FETCH FROM LAKE ONTARIO AND TRAILING MID- LEVEL TROUGH COULD CONTRIBUTE TO SOME LIGHT RAIN/MOUNTAIN SNOW SHOWERS DURING CHRISTMAS DAY...ESPECIALLY IN OROGRAPHIC ENHANCED AREA INTO THE NRN ADIRONDACKS. COULD SEE A LIGHT COATING-1" SNOWFALL ACROSS THE MTN SUMMITS...BUT NOT ANTICIPATING ANY TRAVEL ISSUES DUE TO SNOW WITH TEMPS AT LOWER ELEVATIONS WELL ABOVE FREEZING. HIGH TEMPERATURES GENERALLY IN THE LOW TO MID 40S IN MOST LOCATIONS...WHICH IS DEFINITELY AN ATYPICAL +12 TO +15DEG FROM CLIMATOLOGICAL MEANS. MAY ALSO SEE SOME PERIODS OF SUNNY BREAKS ON CHRISTMAS. QUIETER WEATHER RETURNS THURSDAY NIGHT INTO FRIDAY WITH DIMINISHING WIND. HIGH PRESSURE BUILDS ACROSS THE ERN CONUS WITH 850MB TEMPS REMAINING +2 TO +4C RANGE DURING FRIDAY. THUS...LOWS GENERALLY IN THE 30S THURSDAY NIGHT (LOCALLY UPR 20S ADIRONDACKS AND NE KINGDOM) AND BACK INTO THE LOWER 40S FOR FRIDAY. SHOULD SEE PARTLY TO MOSTLY SUNNY CONDITIONS ON FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 326 AM EST WEDNESDAY...SURFACE HIGH PRESSURE OVER THE CAROLINAS SLIDES INTO THE ATLANTIC, PUTTING THE NORTH COUNTRY IN WARMING SOUTHWEST FLOW; WHILE WEAK UPPER LEVEL ENERGY MOVING NORTH OF THE AREA KEEPS PARTLY CLOUDY SKIES AHEAD OF AN APPROACHING UPPER LEVEL TROUGH FRIDAY NIGHT. THIS TROUGH WILL BE REFLECTED AT THE SURFACE AS A LOW PRESSURE SYSTEM MOVING TO OUR NORTHWEST BRINGS THE CHANCE FOR RAIN AND SNOW SHOWERS SATURDAY AFTERNOON. A COLD FRONT WILL MOVE ACROSS THE AREA FOR THE LATTER HALF OF THE WEEKEND, THOUGH MODEL GUIDANCE DIFFERS ON AVAILABLE MOISTURE AND TIMING. THE FRONT LOOKS TO CLEAR SOUTHEASTERN VERMONT SUNDAY EVENING...WITH NORTHWEST FLOW AND RESIDUAL MOISTURE PROVIDING A CHANCE FOR UPSLOPE SNOW SHOWERS ON MONDAY. ANOTHER LOW PRESSURE SYSTEM WILL DEVELOP OVER THE TENNESSEE RIVER VALLEY LATE MONDAY, TRAVELING NORTHEAST AND POSSIBLY BRINGING MORE PRECIPITATION LATE MONDAY NIGHT THROUGH TUESDAY. AGAIN THE DETAILS ON THIS SYSTEM DIFFER ON EACH MODEL, BUT OVERALL AN ACTIVE PATTERN EXPECTED FOR THE LONG TERM. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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THROUGH 18Z THURSDAY...MAJOR AVIATION IMPACTS ANTICIPATED OVER THE NEXT 12 TO 24 HRS WITH LOW CIGS/VIS THRU TONIGHT...FOLLOWED BY VERY STRONG/GUSTY WINDS ON THURSDAY MORNING...WITH AREAS OF MODERATE TO HIGH TURBULENCE LIKELY. CRNT CONDITIONS SHOW A MIX OF IFR AT MPV/SLK/MSS WITH MVFR AT PBG/RUT AND VFR AT BTV. EXPECT MVFR TO BRIEF PERIODS OF IFR THIS AFTN/EVENING IN PERIODS OF MODERATE RAIN. BEST CHC FOR PROLONGED IFR CIGS/VIS WL BE AT MPV/MSS THRU THIS EVENING. AS MID LVL DRY SLOT DEVELOPS THIS EVENING EXPECT RAIN TO BECOME SCATTERED...BUT WITH WARM AIR MOVING OVER A RELATIVELY COLD SNOW PACK...EXPECT AREAS OF LOW CLOUDS AND FOG TO DEVELOP...ESPECIALLY AT MPV/SLK. SHARP COLD FRNT PUSHES ACRS OUR TAF SITES BTWN 06Z-12Z THURSDAY WITH ANOTHER PERIOD OF RAIN...ALONG WITH A WIND SHIFT TO THE SOUTHWEST. THESE SOUTHWEST WINDS WL INCREASE SHARPLY BTWN 10Z-13Z THURSDAY ACRS NORTHERN NY WITH RANGES BTWN 30 AND 40 KNOTS LIKELY...AND SOME GUSTS APPROACHING 50 KNOTS AT MSS. THESE WINDS AND COMPLEX TRRN WL CREATE AREAS OF LLVL TURBULENCE THRU THE PERIOD...WITH MTNS CONTINUING TO BE OBSCURED IN CLOUDS/FOG. RAIN SHOWERS WL TAPER OFF AFT 12Z THURS...WITH GUSTY WINDS SHIFTING INTO VT. OUTLOOK 18Z THURSDAY THROUGH SUNDAY... GUSTY WINDS WL CONT ON THURS AFTN...WITH VALUES BTWN 30 AND 40 KNOTS LIKELY FROM THE SOUTHWEST. CONDITIONS WL SLOWLY IMPROVE TO MVFR TO VFR BY FRIDAY AS SFC HIGH PRES BUILDS INTO THE REGION. NEXT WEAK SYSTEM ARRIVES LATE SAT INTO SUNDAY WITH A CHC OF MAINLY RAIN SHOWERS ALONG WITH MVFR CIGS POSSIBLE AT SLK/MSS/MPV.
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&& .HYDROLOGY... STORM TOTAL RAINFALL FORECAST FOR MUCH OF VERMONT AND ESSEX COUNTY NY OF 1 TO 1.25 INCHES, AND .50 TO 1 INCH INTO THE NORTHERN ADIRONDACKS AND ST. LAWRENCE VALLEY. SNOWPACK HOLDING 1.5 TO 2.5 INCHES OF SNOW WATER EQUIVALENT, AND MUCH OF THE SWE IS FORECAST TO BE RELEASED IN THE UPCOMING MELT EPISODE. RUNOFF FROM COMBINED RAINFALL/SNOWMELT OF 2.5 TO 3.5 INCHES TOTAL SHOULD BE SUFFICIENT TO GENERATE MINOR FLOODING. INTITIAL FLOOD PROBLEMS WILL BE IN POOR DRAINAGE AND FIELD FLOODING BEGINNING TONIGHT, ESPECIALLY DITCHES AND CULVERTS THAT MIGHT BE CLOGGED WITH SNOW. AS EVENT UNFOLDS FLOOD CONCERNS SHIFT TO MAIN STEM RIVERS REACHING MINOR FLOOD STAGE, INCLUDING THE WINOOSKI AT ESSEX JCT, THE OTTER CREEK AT CENTER RUTLAND, AND THE AUSABLE AT AUSABLE FORKS. MOST OF THE CRESTS SHOULD OCCUR VERY LATE TONIGHT INTO CHRISTMAS MORNING. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH FRIDAY MORNING FOR VTZ001>012-016>019. NY...HIGH WIND WARNING FROM 6 AM TO 6 PM EST THURSDAY FOR NYZ026- 027-031-087. FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH FRIDAY MORNING FOR NYZ026>031-034-035-087. WIND ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR NYZ028>030- 034-035. && $$ SYNOPSIS...BANACOS NEAR TERM...HANSON SHORT TERM...BANACOS LONG TERM...KGM AVIATION...TABER HYDROLOGY...HANSON

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