Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 241854 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 254 PM EDT FRI APR 24 2015 .SYNOPSIS... UNSEASONABLY COOL WEATHER CONTINUES THROUGH THIS WEEKEND WITH SPOTTY SHOWERS OR SPRINKLES. UNSETTLED WEATHER AND BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH NEXT WEEK AS WELL. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... THROUGH 8 PM... UPPER LOW AND COLD POOL IN PLACE OVER NEW NEW ENGLAND. A WEAK SHORTWAVE MOVES THROUGH THE CYCLONIC FLOW AROUND THIS LOW AND CROSSES NEW ENGLAND TOWARD 00Z. RH FORECAST PROFILES SHOW A LAYER OF HIGH RH VALUES BETWEEN 850 AND 700 MB THROUGH 00Z...ALTHOUGH VERTICAL MOTION IS SUBSIDENT. WE COULD SEE A FEW SPRINKLES OR FLURRIES LATE TODAY/THIS EVENING. TONIGHT...LINGERING CLOUD SHIELD UNDER THE UPPER LOW AND COLD POOL...BUT THIS SHOULD START TO LIFT OUT TO THE NORTH AND EAST SOMEWHAT. SO WE EXPECT AT LEAST PARTIAL CLEARING TONIGHT WITH THE BEST CHANCE OVER CONNECTICUT. PRESSURE GRADIENT STAYS ENOUGH TO KEEP THE AIR MOVING...SO FROST IS NOT LIKELY EXCEPT POSSIBLY IN THE MOST SHELTERED OF LOCATIONS THAT CLEAR. ON THE OTHER HAND TEMPERATURES WILL BE SIMILAR TO LAST NIGHT OR PERHAPS A DEGREE OR TWO COOLER. EXPECTED RANGE IS IN THE UPPER 20S AND 30S...AND FREEZING TEMPS IN PARTS OF THE ACTIVE GROWING ZONE /CT-RI- SOUTHEAST MA/. WE PLAN ON CONVERTING THE EXISTING FREEZE WATCH TO A FREEZE WARNING FOR NORTHERN CT AND NORTHWEST RI. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... SATURDAY...UPPER CLOUD SHIELD AND COLD POOL WILL BE FOCUSSED OVER NORTHERN NEW ENGLAND BUT CLOSE ENOUGH TO AFFECT US. DAYTIME HEATING AND A SHORTWAVE CYCLING AROUND THE LOW MAY PUSH CLOUDS BACK OUR WAY DURING THE DAY. THE SURFACE LAYER WILL BE DRIER...SO MOST ATTEMPTS AT PRECIPITATION SHOULD EVAPORATE ON THE WAY DOWN. TEMPS AT 850 MB ARE FORECAST AROUND -2C...WHICH SUPPORTS MAX SFC TEMPS IN THE 50S. WINDS ALOFT IN THE MIXED LAYER REACH 20 KNOTS...SO EXPECT ANOTHER DAY OF GUSTS EITHER SIDE OF 20. SATURDAY NIGHT... WEAK RIDGE BUILDS OVER SOUTHERN NEW ENGLAND PROVIDING CLEARING SKIES AND LIGHT WINDS. RADIATIONAL COOLING WITH DEW POINTS IN THE 30S...SO MIN SFC TEMPS SHOULD BE IN THE 30S. && .LONG TERM /SUNDAY THROUGH FRIDAY/... HIGHLIGHTS... * BELOW NORMAL TEMPERATURES THROUGH NEXT WEEK * SCATTERED DIURNAL SHOWERS THIS WEEKEND INTO MID-NEXT WEEK * LOW CONFIDENCE ON COASTAL SYSTEM THURS/FRIDAY. OVERVIEW... DEEP CLOSED LOW OVER THE REGION BEGINS TO GRADUALLY PIVOT EAST OFFSHORE NOVA SCOTIA ON SAT BUT THEN BECOMES NOTABLY ELONGATED BY SUN AS ADDITIONAL ENERGY DROPS SOUTH DOWN ACROSS THE NORTHEAST. THE 00Z GEM IS THE WEAKEST SOLUTION WHILE THE 00Z GFS/00Z NAM/00Z UKMET AND 00Z ECMWF ARE ALL BETTER CLUSTERED WITH DEPTH AND TIMING THROUGH SUNDAY. BY NEXT WEEK APPEARS UNSETTLED WEATHER AND BELOW NORMAL TEMPS CONTINUE AS BLOCKING PATTERN PERSIST...SUPPORTED BY -NAO/-AO/+PNA. UPPER LEVEL LOW AND CONTINUED COLD POOL WILL KEEP ON SPINNING OVER THE REGION MONDAY AND BEGIN TO EXIT LATE TUESDAY. STILL LOTS OF QUESTIONS ABOUT THE MIGRATION OF THE DESERT CUTOFF LOW AS IT MOVES ACROSS THE SOUTHEAST AND ITS POTENTIAL WRAP UP INTO ANOTHER CLOSED LOW FOR NEW ENGLAND. A KEY COMPONENT OF THE SYSTEM`S INTENSIFICATION WILL BE THE INCORPORATION OF SOUTHEASTWARD-MOVING SHORTWAVE ENERGY AND WHERE THIS NORTHERN STREAM ENERGY WILL PHASE WITH THE CUTOFF SYSTEM. CURRENTLY THE 00Z GFS PHASES THE SOUTHERN PLAIN WAVE FASTER THAN THE EC WHICH IS MORE AMPLIFIED. THE EC/S NORTHERN STREAM IS FARTHER EASTWARD THAN THE GFS...IN WHICH THE EC SEEMS TO PULL A COASTAL LOW CLOSER TO THE REGION BY THUS/FRI. REGARDLESS APPEARS THAT A COASTAL LOW WILL HAVE AN IMPACT ON THE REGION LATE IN THE WORK WEEK. FELT ENSEMBLE GUIDANCE WAS BEST FOR THE WORK WEEK. DETAILS... * SUNDAY...HIGH CONFIDENCE. STRONG CUTOFF LOW WILL CONTINUE TO IMPACT THE NORTHEAST DURING THIS TIME PERIOD. UPPER LEVEL RIDGE OVER THE CENTER CONUS WILL BUILD PUSHING THE BULK OF THE ENERGY OFFSHORE SAT NIGHT BEFORE THE LOW MIGRATES BACK TOWARDS NEW ENGLAND BY SUNDAY. STRONG SHORTWAVE WILL MOVE THROUGH THE REGION FROM THE NORTH INCREASING PRECIPITATION CHANCES ON SUNDAY. TEMPS MAY REACH 60F AS COLD POOL IS STILL OFFSHORE. * MONDAY INTO TUESDAY...MODERATE CONFIDENCE. THE UPPER LEVEL LOW WILL RETROGRADE INCREASING THE CHANCES OF PRECIP AS 2 POTENT SHORTWAVES MORE THROUGH THE FLOW FROM THE NORTH. COLD POOL ALOFT SEEMS TO SIT OVER THE REGION AS WELL. CHANCE FOR SHOWERS WILL BE HIGHER THAN FOR THIS UPCOMING WEEKEND AS LAPSE RATES WILL BE STEEPER AND SOME HINTS OF INSTABILITY. INCREASED POPS ESP ALONG THE MASS COASTLINE WHERE FORCING COULD OCCUR IF SEA BREEZE DEVELOPS. TEMPERATURES APPEAR TO BE AROUND 10 DEGREES COOLER ON MONDAY THANKS TO THE STRONG COLD POOL OVER THE REGION. * WEDNESDAY AND BEYOND...LOW CONFIDENCE. STILL SOME UNCERTAINTY IN THIS PORTION OF THE FORECAST. EVERYTHING IS DEPENDENT ON HOW THE CUT-OFF LOW IN THE DESERT SOUTHWEST AND DIGGING NORTHERN STREAM WAVES BEHAVES. CURRENTLY BELIEVE WED IS A TRANSITION DAY WITH MID LEVEL RIDGE BUILDING INTO THE REGION BUT KEEPING TEMPS BELOW NORMAL. WATCHING THE DEVELOPMENT OF A COASTAL LOW ON THURSDAY/FRIDAY. BOTH THE GFS AND EC HAVE SHOWN THE COASTAL LOW THIS TIME AROUND...SO CONFIDENCE IS INCREASING THAT IT WILL OCCUR. THIS IS SUPPORTED BY THE ENSEMBLES. THE GFS IS SLIGHTLY FARTHER OFFSHORE AND FASTER COMPARED TO THE EC...REGARDLESS WET WEATHER AND COOL TEMPS WILL CONTINUE. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /THROUGH SATURDAY/... THIS AFTERNOON...HIGH CONFIDENCE. VFR WITH NORTHWEST WINDS GUSTING 20-22 KNOTS. TONIGHT AND SATURDAY...HIGH CONFIDENCE. VFR. POSSIBLE BRIEF MVFR IN SPOTTY SHOWERS DURING THE DAY SATURDAY. NORTHWEST WINDS GUSTING AROUND 20 KNOTS. SATURDAY NIGHT...HIGH CONFIDENCE. VFR WITH LIGHT WIND. KBOS TAF...HIGH CONFIDENCE IN OVERALL TAF. KBDL TAF...HIGH CONFIDENCE IN OVERALL TAF. OUTLOOK...SUNDAY THROUGH TUESDAY... MODERATE CONFIDENCE. VFR WITH MVFR CONDITIONS IN SCT SHOWERS. SEA BREEZE DEVELOPMENT IS POSSIBLE ALONG THE EAST COAST EACH DAY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TONIGHT THROUGH SATURDAY/... SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... WEST-NORTHWEST WINDS GUST 20 TO 25 KNOTS WITH STRONGEST GUSTS OFFSHORE. SEAS LINGER NEAR 5 FEET ON THE OUTER WATERS THROUGH SATURDAY AND THEN SUBSIDE. SEAS BELOW 5 FEET ALL OTHER WATERS THROUGH THE PERIOD. SMALL CRAFT ADVISORY LINGERS ON THE OUTER WATERS THROUGH SATURDAY MORNING DUE TO SEAS AND OCCASIONAL GUSTS TO 25 KNOTS. SCA ALSO LINGERS ON RI AND BLOCK ISLAND SOUNDS TONIGHT MOSTLY DUE TO WINDS AT OR NEAR 25 KNOTS. OUTLOOK...SUNDAY THOUGH TUESDAY... HIGH CONFIDENCE. UPPER LEVEL LOW WILL CONTINUE TO SPIN ACROSS THE NORTHEAST. HIT OR MISS SHOWERS POSSIBLE DURING THE DAY. WIND AND SEAS TO REMAINS BELOW SCA ON SUNDAY. POTENT COLD POOL WILL FILTER IN FROM THE NORTH CREATING STRONG CAA AN INCREASE WINDS/SEAS FOR MONDAY AND TUESDAY. SCA MAY BE NEEDED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR CTZ002>004. MA...NONE. RI...FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR RIZ001-003. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ250- 254>256. && $$ SYNOPSIS...WTB/DUNTEN NEAR TERM...WTB SHORT TERM...WTB LONG TERM...DUNTEN AVIATION...WTB/DUNTEN MARINE...WTB/DUNTEN

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