Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 240552 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1252 AM EST WED DEC 24 2014 .SYNOPSIS... WEAK LOW PRESSURE PASSES OFFSHORE TONIGHT. A MUCH STRONGER STORM TRACKING ACROSS THE GREAT LAKES WILL BRING HEAVY RAIN...GUSTY WINDS AND MINOR COASTAL FLOODING WEDNESDAY INTO CHRISTMAS MORNING. DRY WEATHER WITH ABOVE NORMAL TEMPERATURES WILL FOLLOW FROM CHRISTMAS AFTERNOON INTO SAT. A COLD FRONT MAY BRING A FEW RAIN OR SNOW SHOWERS SUNDAY. ANOTHER STORM MAY AFFECT US SUNDAY NIGHT INTO MON...BUT IT COULD ALSO PASS WELL TO OUR SOUTH. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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1245 AM UPDATE... LOW CLOUDS AND AREAS OF DRIZZLE AND FOG WILL CONTINUE OVERNIGHT AS LOW LEVEL E/NE FLOW AND ABUNDANT LOW LEVEL MOISTURE REMAINS IN PLACE WITH DRIER AIR IN THE MID LEVELS. TEMPS WILL NOT CHANGE MUCH OVERNIGHT.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... UPPER RIDGE BUILDS TO HIGHER AMPLITUDE BUT SHIFTS EAST OF NEW ENGLAND. DEEP TROUGH OVER THE PLAINS MOVES EAST. THIS BRINGS A DEEP SOUTH-SOUTHWEST FLOW OVER THE EASTERN USA WITH A STRONG 150 KNOT UPPER JET DRIVING NORTH THROUGH IT. THIS WILL BRING AN AIRMASS WITH PRECIPITABLE WATER VALUES OF 1.5" OR HIGHER...OVER 3 STD DEVIATIONS ABOVE NORMAL AND NEAR THE MAXIMUM HISTORICAL VALUE. LOW LEVEL SOUTHWEST JET OF 50-65 KNOTS ARRIVES WEDNESDAY AFTERNOON AND CONTINUES THROUGH WEDNESDAY NIGHT...THEN SHIFTS EAST CHRISTMAS MORNING. LOW PRESSURE LIFTS NORTH FROM THE GULF OF MEXICO TO THE GREAT LAKES...THEN SWINGS A COLD FRONT TOWARD NEW ENGLAND. GOOD MODEL AGREEMENT ON MOVEMENT OF THE FRONT...REACHING THE CONNECTICUT VALLEY BY 12Z THURSDAY. THIS SYSTEM WILL GENERATE GOOD LOW LEVEL LIFT...AND BY WEDNESDAY NIGHT THE APPROACHING UPPER JET SHOULD SUPPORT LIFT FROM THE UPPER PART OF THE STORM. COMBINE THIS WITH THE VERY HUMID AIRMASS...AND WE SHOULD EXPECT PERIODS OF RAIN WEDNESDAY AND ESPECIALLY WEDNESDAY NIGHT WITH SOME HEAVY DOWNPOURS. THIS SHOULD BRING AN ADDITIONAL 1-2 INCHES OF RAIN. THE DYNAMICS MAY ALSO DRIVE SOME ISOLATED THUNDER...WITH THE BEST CHANCE LATE WEDNESDAY NIGHT AHEAD OF THE COLD FRONT. CONCERNS...RAIN. THE AIRMASS HAS A HIGH RAINFALL POTENTIAL BUT MAY NOT TAP ALL OF THAT POTENTIAL. HOWEVER THERE MAY BE SOME LOCALLY HEAVIER DOWNPOURS THAT PUSH TOTALS IN A FEW SPOTS ABOVE 2 INCHES. WITH OR WITHOUT THIS...THE AMOUNT OF RAIN MAY BE ENOUGH TO CAUSE SOME URBAN/POOR DRAINAGE FLOODING. WE HAVE ISSUED A FLOOD WATCH FOR MOST OF OUR AREA FOR LATE WEDNESDAY THROUGH THURSDAY MORNING. CONCERNS...WIND...PER BUFKIT THE LOW LEVEL JET OF 55 TO 65 KNOTS WILL REACH DOWN TO ABOUT 1000 FEET AGL. THIS WILL BE LOW ENOUGH TO REACH THE HIGHER HILLTOPS AND MAY INCH CLOSER TO THE SURFACE. IT IS FACING A STRONG TEMPERATURE INVERSION NEAR THE GROUND WHICH MAY KEEP SOME OF THIS WIND ABOVE THE GROUND. HEAVY DOWNPOURS MAY PROVIDE A CHANNEL TO BRING SOME OF THAT WIND DOWN THE FINAL THOUSAND FEET TO THE SURFACE. IN ANY CASE...WE EXPECT SOME GUSTY SOUTH WINDS WEDNESDAY AFTERNOON THROUGH 12Z THURSDAY WITH VALUES TO AT LEAST 30 KNOTS AND POSSIBLY APPROACHING 40 KNOTS. CONCERNS...COASTAL FLOODING...ASTRONOMICAL TIDES WILL REMAIN HIGH WITH A CONTINUED SOUTHEAST WIND ALONG THE MASS EAST COAST DURING THE MORNING. MORE ON THIS IN THE COASTAL FLOOD SECTION. WARM ADVECTION WEDNESDAY AFTERNOON WILL BRING WARMER TEMPERATURES WITH VALUES REACHING THE 50S AND POSSIBLY REACHING 60 IN SOME SPOTS. TEMPERATURES AND DEW POINTS WEDNESDAY NIGHT WILL NOT FALL MUCH WITH VALUES LINGERING IN THE 50S. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * DRY AND WINDY CHRISTMAS AFTERNOON WITH GUSTS TO 45 MPH POSSIBLE * CONTINUED DRY WITH ABOVE NORMAL TEMPERATURES FRI AND SAT * A STORM MAY AFFECT THE REGION SUNDAY NIGHT INTO MON...BUT CONFIDENCE IS LOW OVERVIEW... MODELS CONTINUE TO EXHIBIT GOOD OVERALL AGREEMENT INTO FRIDAY. AFTER THAT TIME..THE ECMWF CONTINUES TO MAINTAIN A SHARPER MID LEVEL TROUGH OVER THE CENTRAL USA, THIS TROUGH WOULD RESULT IN A STORM TRACK CLOSER TO SOUTHERN NEW ENGLAND EARLY NEXT WEEK. THAT SAID...JUST ABOUT ALL GUIDANCE IS INDICATING AT LEAST SOME POTENTIAL FOR A PERIOD OF WET WEATHER EARLY NEXT WEEK. HAVE LOW CONFIDENCE IN THE DETAILS OF STORM TRACK EARLY NEXT WEEK. WILL KEEP A CHANCE OF SHOWERS IN THE FORECAST LATE SUNDAY INTO MONDAY UNTIL THIS CRITICAL DETAIL CAN COME INTO BETTER FOCUS. CHRISTMAS DAY...HEAVY RAIN WILL LIKELY BE ONGOING CHRISTMAS MORNING ACROSS THE COASTAL PLAIN. RAIN THEN MOVES OUT BY MIDDAY WITH SKIES BECOMING CLEARER IN THE AFTERNOON. GUSTY SOUTHWEST WINDS IN THE MORNING NEAR THE COAST ASSOCIATED WITH THE LOW-LEVEL JET AND HEAVIER RAINFALL. ALL AREAS WILL SEE STRONG WEST WIND GUSTS IN THE AFTERNOON AS COLD ADVECTION DEVELOPS WITH STEEPENING LOW LEVEL LAPSE RATES. WIND GUSTS TO 45 MPH WILL BE POSSIBLE AND WIND ADVISORIES MAY BE NEEDED. MAX TEMPERATURES IN THE 50S TO NEAR 60 DEGREES WILL OCCUR IN THE MORNING...WITH TEMPS FALLING DURING THE AFTERNOON. FRIDAY INTO SAT... HIGH PRESSURE CENTERED TO OUR SOUTH BRINGS DRY WEATHER WITH ABOVE NORMAL TEMPERATURES. THE MILDER DAY WILL BE SATURDAY. SUNDAY INTO TUESDAY...LOW CONFIDENCE FORECAST. A COLD FRONT MAY BRING A FEW RAIN/SNOW SHOWERS SUNDAY. WE WILL THEN HAVE TO WATCH FOR POSSIBLE FRONTAL WAVE SUNDAY NIGHT INTO MONDAY. THIS WAVE MAY END UP TOO FAR SOUTH BUT WILL KEEP LOW POPS IN THE FORECAST. SOME OF THE GUIDANCE...MOST NOTABLY THE ECMWF...KEEPS A LOW PRESSURE NEAR OUR REGION INTO TUESDAY MORNING. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE. THROUGH 12Z...WIDESPREAD IFR/LIFR CONDITIONS IN STRATUS...DRIZZLE AND FOG. TODAY AND TONIGHT...WIDESPREAD IFR/LIFR CONDITIONS CONTINUE WITH RAIN OVERSPREADING THE REGION LATER THIS MORNING THROUGH THE AFTERNOON AND CONTINUING TONIGHT. A BAND OF LOCALLY HEAVY SHOWERS AND ISOLATED THUNDERSTORMS WITH POTENTIALLY STRONG WINDS MAY MOVE ACROSS THE REGION 09-12Z. LOW LEVEL WIND SHEAR WILL DEVELOP LATE TODAY AND THIS EVENING AS 2000 FT WINDS INCREASE TO 40-50 KT. THE LLWS WILL SHIFT TO SE NEW ENGLAND LATE TONIGHT WITH 2000 FT WINDS INCREASING TO 60 KT. KBOS TERMINAL...HIGH CONFIDENCE IN IFR/LIFR CONDITIONS. KBDL TERMINAL...HIGH CONFIDENCE IN IFR/LIFR CONDITIONS. OUTLOOK...THURSDAY THROUGH SUNDAY... CHRISTMAS...MODERATE CONFIDENCE. IFR IN RAIN TO START...THEN CONDITIONS IMPROVE TO VFR IN THE AFTERNOON FROM WEST TO EAST. WEST WIND GUSTS TO 35-40 KT POSSIBLE IN THE AFTERNOON. FRIDAY AND SATURDAY...HIGH CONFIDENCE. VFR. SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. SCATTERED MVFR IN SHOWERS AS A COLD FRONT PASSES THROUGH.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE. TONIGHT... EAST WINDS NEAR 20 KNOTS WILL DIMINISH. BUT ROUGH SEAS WILL KEEP SMALL CRAFT ADVISORY GOING ON MOST WATERS. WEAK LOW PRESSURE MOVING UP THE COAST WILL PASS JUST OFFSHORE...BRINGING DIMINISHING LIGHT RAIN ALONG WITH CLOUDS/FOG/DRIZZLE. WEDNESDAY AND WEDNESDAY NIGHT...STRONG SOUTH WINDS WILL MOVE UP THE COAST FROM THE CAROLINAS WEDNESDAY...REACHING THE NEW ENGLAND WATERS IN THE AFTERNOON AND LINGERING THROUGH THE NIGHT. WINDS WILL REACH 50-65 KNOTS ABOUT 2000 FEET ABOVE THE OCEAN SURFACE. BUT A STRONG TEMPERATURE INVERSION MAY KEEP ALL OF THIS WIND FROM REACHING THE SURFACE. EVEN SO...HEAVY DOWNPOURS MAY PROVIDE A CHANNEL FOR SOME OF THIS WIND TO REACH THE SURFACE IN GUSTS. WE ARE CURRENTLY FORECASTING GUSTS TO 30 KNOTS OR THE LOWER 30S. LOW CONFIDENCE FOR GUSTS REACHING GALE FORCE. EXPECT FOG AND RAIN WITH LOCAL HEAVY DOWNPOURS. OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE CHRISTMAS...WINDS SHIFT TO SW/W WITH GALE FORCE GUSTS POSSIBLE. IMPROVING VSBYS IN THE AFTERNOON AS RAIN MOVES OUT. FRI AND SAT...EXPECT WEST WINDS BELOW SMALL CRAFT ADVISORY LEVELS FRI. INCREASING SOUTHWEST WINDS SAT WITH GUSTS TO 25 KT. SUNDAY...WEST TO NORTHWEST WINDS MAY GUST TO 25 KT ACROSS THE OUTER COASTAL WATERS. MAY ALSO SEE 5 FOOT SEAS ACROSS THE OUTER COASTAL WATERS AS WELL. && .TIDES/COASTAL FLOODING... EASTERN MASSACHUSETTS COAST: HIGH TIDE AT BOSTON WILL BE 11.7 FT AT MIDDAY WEDNESDAY WITH A SURGE OF AROUND 1.0 FT. THE SURGE TODAY /TUESDAY/ SHOWED MINOR SPLASHOVER ALONG THE EAST MASSACHUSETTS COAST. EXPECT SIMILAR EFFECTS WEDNESDAY. A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR THE EAST MASSACHUSETTS COAST FOR THE MIDDAY WEDNESDAY HIGH TIDE. SOUTH COAST: WE DO NOT EXPECT MUCH IF ANY COASTAL FLOODING ALONG THE SOUTH COAST. NOT ENOUGH WIND OR SURGE FOR THE WEDNESDAY EVENING HIGH TIDE. HIGHEST SURGE OF 1-2 FEET LIKELY TO OCCUR DURING LOW TIDE LATE WED NIGHT WITH THE SURGE AND SEAS DECREASING DURING THE CHRISTMAS MORNING HIGH TIDE. WORST CASE IS MINOR SPLASHOVER FOR THE CHRISTMAS MORNING HIGH TIDE BUT EVEN THIS IS NOT LOOKING FAVORABLE. && .CLIMATE... RECORD HIGHS FOR DEC 24 / DEC 25... BOS...61 IN 1996 / 65 IN 1889 PVD...60 IN 1990 / 63 IN 1964 BDL...59 IN 1996 / 64 IN 1964 ORH...57 IN 1996 / 60 IN 1964 && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...FLOOD WATCH FROM THIS AFTERNOON THROUGH THURSDAY MORNING FOR CTZ002>004. MA...FLOOD WATCH FROM THIS AFTERNOON THROUGH THURSDAY MORNING FOR MAZ002>022-026. COASTAL FLOOD ADVISORY FROM 9 AM THIS MORNING TO 4 PM EST THIS AFTERNOON FOR MAZ007-014>016-019-022. RI...FLOOD WATCH FROM THIS AFTERNOON THROUGH THURSDAY MORNING FOR RIZ001>007. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST THURSDAY FOR ANZ231>234-236. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST THURSDAY FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ250-251- 254>256.
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&& $$ SYNOPSIS...WTB/BELK NEAR TERM...KJC SHORT TERM...WTB LONG TERM...BELK AVIATION...BELK/KJC MARINE...WTB/BELK TIDES/COASTAL FLOODING...WTB CLIMATE...STAFF

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