Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 251721 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1221 PM EST TUE NOV 25 2014 .SYNOPSIS... A WEAK COLD FRONT WILL MOVE ACROSS THE REGION THIS MORNING. THIS WILL ALLOW FOR A QUIET AND MILD DAY WITH SOME GUSTY SOUTHWEST WINDS INTO THE AFTERNOON. A WINTER STORM IS LIKELY TO IMPACT THE REGION WEDNESDAY AND WEDNESDAY NIGHT WITH IMPROVING CONDITIONS THANKSGIVING DAY. GRADUALLY TURNING COLDER INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WEAK COLD FRONTAL BOUNDARY HAS PUSHED THROUGH MUCH OF THE AREA AND IS ACROSS THE CANAL RIGHT NOW. DEWPOINTS HAVE DROPPED SIGNIFICANTLY...AS THEY WERE IN THE 50F EARLIER AND NOT HAVE DROPPED TO THE UPPER 20S TO LOW 30S. OCCASIONAL WIND GUSTS OF NEAR 20 MPH HAD BEEN OBSERVED THROUGH THE OBS AS MIXING CONTINUES. SURFACE TEMPS ARE STILL HOLDING OUT IN THE UPPER 50S TO LOW 60S. ANY LINGERING FOG ACROSS THE CAPE AND THE ISLANDS WILL BE SWEPT OFFSHORE WITHIN THE NEXT HOUR OR TWO. CLOUDS CONTINUE TO DOMINATE THE SKIES TODAY THANKS TO ADVECTING TROPICAL MOISTURE...WHICH WILL EVENTUALLY BE OUR STORMS MOISTURE WITHIN THE NEXT 24 HOURS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... TONIGHT... WEAK RIDGE MOVES OFFSHORE AS LIGHT W WINDS CONTINUE TO VEER TO N. MEANWHILE...LOW PRES TAKES SHAPE OFF THE CAROLINA COAST LATE TONIGHT. WILL SEE PRECIP BLOSSOM S OF NEW ENGLAND OVERNIGHT...AND WILL PUSH INTO S COASTAL AREAS AFTER MIDNIGHT AND QUICKLY SHIFT N BY DAYBREAK. AS TEMPS FALL BACK CLOSE TO OR JUST BELOW FREEZING WELL INLAND...WILL SEE A MIX OF RAIN AND/OR SNOW GENERALLY FROM THE WORCESTER HILLS INTO THE HIGHER TERRAIN OF N CENTRAL CT WESTWARD. QPF DURING THIS TIME IS RATHER LIGHT...BUT COULD BE ENOUGH WELL INLAND TO CAUSE SOME PROBLEMS DURING THE MORNING COMMUTE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... WEDNESDAY THROUGH THURSDAY... *** EARLY SEASON WINTER STORM TO IMPACT MUCH OF THE REGION WED/WED NIGHT *** SYNOPTIC OVERVIEW AND MODEL PREFERENCES... 00Z MODEL SUITE HAS TRENDED SLIGHTLY EASTWARD WITH SURFACE LOW TRACKING OVER OR NEAR THE 40N/70W BENCHMARK...WITH H85 CIRCULATION MOVING ACROSS CAPE COD AND THE ISLANDS AND H7 LOW DEVELOPING AND TRACKING OVER BDL-ORH-MHT LINE. 00Z ECMWF ON THE NORTHWEST EDGE OF THE ENVELOPE AND 00Z GFS ON THE EASTERN EDGE OF THE GUID ENVELOPE. GIVEN EVENT IS STILL 42-48 HRS AWAY /MODEL TIME/ MODEL BLEND STILL THE MOST SKILLFUL OPTION. THE TRACK MENTIONED ABOVE SUPPORTS MODERATE TO HEAVY SNOWS NW OF I-95. THUS HAVE UPGRADED WINTER STORM WATCHES TO WARNINGS FROM HARTFORD COUNTY NORTHWARD THRU THE I-91 CORRIDOR INTO CHESHIRE COUNTY OF NH AND EASTWARD INTO WORCESTER COUNTY FOR A HIGH PROBABILITY OF 6+ INCHES. PTYPE AND SNOWFALL... WARM BOUNDARY LAYER EARLY WED WILL LEAD TO PRECIP BEGINNING AS RAIN ACROSS MUCH OF THE REGION...EXCEPT THE FAR INTERIOR. HOWEVER STRONG FORCING FOR ASCENT AND INCREASING PRECIP INTENSITY /COPIOUS GULF AND ATLC MSTR/ WILL YIELD COOLING VIA DYNAMICAL AND DIABATIC PROCESSES. THIS WILL RESULT IN WET BULB TEMPS BEING REACHED WITH RAIN CHANGING OVER TO SNOW DURING WED AFTERNOON ACROSS MUCH OF THE REGION. RAIN/SNOW LINE APPEARS TO SETUP SOMEWHERE OVER CENTRAL RI INTO INTERIOR SOUTHEAST MA. THESE BOUNDARIES ARE ALWAYS DIFFICULT TO PINPOINT ESPECIALLY AT THIS TIME RANGE. CRITICAL PROCESSES HERE WILL BE STRONG MID LEVEL FGEN. AS OF NOW THE NAM AND GFS SUGGEST STRONG BANDING FEATURE 18Z WED - 00Z THU OVER CENTRAL CT/NORTHWEST RI EXTENDING NORTHEAST THRU WORCESTER COUNTY AND INTO NORTHEAST MA INCLUDING THE GREATER BOSTON AREA. PRECIP INTENSITY ASSOCIATED WITH THIS BAND SHOULD BE SUFFICIENT FOR A CHANGEOVER TO ALL SNOW ALONG WITH SNOW RATES OF 1-2" PER HOUR. IN ADDITION...WITH SURFACE LOW TRACKING VICINITY OF THE 40N/70W BENCHMARK COUPLED WITH STRONG PRES FALLS...SURFACE WINDS OVER NORTHEAST MA INCLUDING BOSTON SHOULD BE BACKING TO THE NNE. THIS WILL PROVIDE ADDITIONAL LOW LEVEL COOLING. IDEALLY WOULD LIKE TO SEE A 1030+ MB HIGH OVER QUEBEC HELPING TO WEDGE THE LOW LEVEL COLD AIR DOWN THE COASTAL PLAIN FROM ME AND NH...THERE IS A 1026 HIGH OVER SOUTHEAST QUEBEC 00Z THU. THIS COMBINED WITH STRONG PRES FALLS JUST OFFSHORE SHOULD HELP A COASTAL FRONT DEVELOP. ALL OF THESE FACTORS MENTIONED ABOVE INCREASE THE RISK FOR A PERIOD OF HEAVY SNOW INTO THE RT-128 CORRIDOR OF EASTERN MA INCLUDING THE GREATER BOSTON AREA. THUS HAVE EXPANDED THE WATCH TO HIGHLIGHT THIS POTENTIAL. OTHERWISE NOT MANY CHANGES FROM PREVIOUS FORECAST. GIVEN PROGRESSIVE NATURE OF SYSTEM...DRY SLOT AND NOT IDEAL SNOW-LIQUID-RATIOS /SLR/ MAX SNOWFALL TOTALS SHOULD BE CAPPED AROUND A FOOT. HIGHEST RISK WHERE EVER MESO SCALE BANDING SETS UP...WHICH RIGHT NOW APPEARS SOMEWHERE FROM CENTRAL CT-WORCESTER COUNTY INTO NORTHEAST MA. OBVIOUSLY THIS IS SUBJECT TO CHANGE GIVEN EVENT IS STILL 42-48 HRS AWAY. WINDS... STRONG LOW LEVEL NORTHEAST JET MOVES ACROSS THE SOUTH COAST OF RI AND MA INCLUDING CAPE COD AND THE ISLANDS. MODELS PROJECTING 50-65 KT AT 925 MB. THIS COUPLED WITH STRONG PRES FALLS AND RELATIVELY WARM OCEAN WATERS PROVIDING A WELL MIXED BLYR WILL YIELD A MODERATE RISK OF 60 MPH WIND GUSTS FROM SOUTH COASTAL PLYMOUTH COUNTY/CAPE COD AND THE ISLANDS. TIMING OF STRONGEST WINDS APPEAR 4 PM WED TIL 1 AM THU. THUS HAVE ISSUED A HIGH WIND WATCH FOR THIS AREA. LATER SHIFTS WILL LIKELY HAVE TO SURROUND THIS AREA WITH A WIND ADVISORY. COASTAL FLOODING... FORECAST TIDES OF 10 FEET EXPECTED AT BOSTON SHORTLY AFTER MIDNIGHT THURSDAY. GIVEN SHORT DURATION OF ONSHORE WINDS AND PRESSURES BEGINNING TO RISE TOWARD HIGH TIDE NOT EXPECTING MUCH IF ANY COASTAL FLOOD ISSUES INCLUDING EROSION. THURSDAY THROUGH MONDAY... MEDIUM RANGE MODELS IN GOOD AGREEMENT THAT SERIES OF WEAK SHORTWAVES WILL ROTATE AROUND BROAD TROUGH IN PLACE OVER EASTERN STATES. THIS WILL MAINTAIN DRY WEATHER AND BELOW AVERAGE TEMPERATURES INTO WEEKEND...ALTHOUGH EXPECT SOME CLOUDINESS FROM TIME TO TIME. WE SHOULD SEE BRIEF MODERATION IN TEMPERATURES SUN AS SW FLOW DEVELOPS AHEAD OF NEXT COLD FRONT...WHICH WILL BRING REINFORCING SHOT OF COLD NEXT MON. MAY SEE FEW SHOWERS WITH PASSAGE OF FRONT SUN NIGHT/MON MORNING...BUT SHOULD BE ISOLATED AT BEST. && .AVIATION /17Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /THROUGH TOMORROW NIGHT/...MODERATE CONFIDENCE. TODAY...VFR CIGS AOA 10KFT. SW WIND GUSTS UP TO 20-25 KT THROUGH MIDDAY ALONG S COAST. TONIGHT...EXPECT VFR CONDITIONS UP TO 09Z THEN CONDITIONS WILL BEGIN TO DETERIORATE FROM VFR TO IFR. TOMORROW AND TOMORROW NIGHT...COASTAL STORM ANTICIPATED. SIGNIFICANT ACCUMULATION SNOWS OVER INTERIOR TERMINALS IMMEDIATELY W OF THE I-95 CORRIDOR. +SN POSSIBLE ESPECIALLY BDL-ORH AND POSSIBLY FOR A TIME AT BOS AROUND 18Z THU. STRONG NE WINDS UP TO 45 KT AT HYA AND ACK AROUND 00Z THU. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. OUTLOOK...THURSDAY THROUGH FRIDAY... THUS AND FRI...VFR. MODERATE CONFIDENCE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE. TODAY...WINDS/SEAS HAVE DIMINISHED ACROSS MASS/IPSWICH BAYS TO ALLOW SMALL CRAFT TO EXPIRE AT 09Z. CONTINUED THE SMALL CRAFT ON THE SOUTHERN OUTER WATERS INTO RI/BI SOUNDS THROUGH THE DAY. SEAS UP TO 11 FT ON THE OPEN WATERS ON SW WINDS GUSTING TO 25 KT...WHICH SHOULD DIMINISH BY EVENING. TONIGHT...THE LULL BEFORE THE STORM. W WINDS DIMINISH AS THEY VEER TO NW-N DURING THE NIGHT. SEAS ON THE EASTERN OUTER WATERS AND DOWN TO THE SOUTHERN OPEN WATERS REMAIN AOA 5 FT. HOWEVER...AS NE WINDS INCREASE DURING WED...GALE AND STORM WATCHES HAVE BEEN ISSUED. OUTLOOK...WEDNESDAY THROUGH FRIDAY... WEDNESDAY INTO THURSDAY...MODERATE CONFIDENCE. NOR`EASTER ANTICIPATED TO PASS AROUND THE 40N/70W BENCHMARK 00Z THU. HIGH PROB OF NE GALES WITH A LOW TO MODERATE RISK OF STORM FORCE GUSTS 21Z WED TO 06Z THU. HEAVY RAIN LENDING TO REDUCED VISIBILITIES AT TIMES. FRI...MODERATE CONFIDENCE. SCA CONDITIONS SHOULD PERSIST ON OUTER WATERS DUE TO 25KT GUSTS AND 5 FT SEAS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 10 AM EST THURSDAY FOR CTZ002. WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR CTZ003-004. MA...WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 10 AM EST THURSDAY FOR MAZ002>004-008>011. HIGH WIND WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT FOR MAZ019-022>024. WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR MAZ005>007-012>016-026. NH...WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 10 AM EST THURSDAY FOR NHZ011. WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR NHZ012-015. RI...HIGH WIND WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT FOR RIZ008. WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR RIZ001-003. MARINE...STORM WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR ANZ231>235-237-254>256. GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT FOR ANZ230-236-250-251. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ235- 237-255-256. && $$ SYNOPSIS...NOCERA/EVT NEAR TERM...DUNTEN SHORT TERM...EVT LONG TERM...NOCERA AVIATION...NOCERA/EVT MARINE...NOCERA/EVT

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