Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 011444 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1044 AM EDT FRI MAY 1 2015 .SYNOPSIS... COOL DAY TODAY ACROSS THE AREA THANKS TO CONTINUED FLOW OFF THE GULF OF MAINE. WARMER TEMPERATURES ARE EXPECTED TOMORROW. A FEW SHOWERS ARE POSSIBLE EACH DAY. HIGH PRESSURE BUILDS OVER THE REGION DURING EARLY NEXT WEEK. A COLD FRONT SWEEPS SOUTH ACROSS THE REGION TUESDAY AND THEN STALLS SOUTH OF NEW ENGLAND MIDWEEK. HIGH PRESSURE REBUILDS WITH DRY AND WARMING WEATHER WEDNESDAY AND THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1044 AM UPDATE... NO MAJOR CHANGES TO THE ONGOING FORECAST. EAST TO NORTHEAST FLOW MAINTAINING CLOUDS ACROSS SOUTHERN NEW ENGLAND THIS MORNING. THESE CLOUDS WERE ALREADY STARTING TO BREAK UP WEST OF THE WORCESTER HILLS. WE STILL EXPECT THIS TREND TO CONTINUE AND SLOWLY WORK ITS WAY EAST THROUGH THIS AFTERNOON. MINOR TWEAKS TO TEMPERATURES AS WELL...TO REFLECT THE SKY COVER CHANGES. PREVIOUS DISCUSSION... WITH THE TRAPPED MOISTURE BENEATH A MODEST SUBSIDENCE INVERSION... EXPECT THIS CLOUDINESS TO LINGER MUCH OF THE MORNING...BUT DO SEE THE LIKELIHOOD OF SOME MID-LATE DAY BREAKS AS THE DRIER AIR MIXES THROUGH TO THE BL. IN SPITE OF THIS...THE CONTINUED ONSHORE FLOW WILL LIKELY LEAD TO TODAY BEING ONE OF THE COOLER DAYS RECENTLY... WITH MOST PLACES REMAINING IN THE 50S FOR HIGHS...OR EVEN 40S NEAR THE COAST. A WEAK INSTABILITY TROF WELL TO THE W IS LIKELY TO GENERATE SOME -SHRA...BUT FEEL THE BULK OF THESE REMAIN OUTSIDE OF OUR CWA. OTHERWISE...THE OCEAN LOW PRES TO THE S IS LIKELY TO USURP MUCH OF THE MOISTURE/DYNAMICS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... TONIGHT... FAIRLY SIMILAR CONDITIONS OVERALL AS WEAK HIGH PRES CONTINUES TO SLIDE TO THE E. THERE WILL LIKELY BE SOME LINGERING LOW-MID CLOUDS ASSOCIATED WITH A SHORTWAVE MOVING N-S ACROSS THE REGION OVERNIGHT. HOWEVER...SOME INDICATIONS SUGGESTS THE DEVELOPMENT OF MARINE STRATUS/FOG OFFSHORE WHICH COULD SLIDE ACROSS MAINLY E MA DURING THE EARLY MORNING HOURS. HOWEVER...BUFKIT PROFILES AND CMC DATA /WHICH IS TYPICALLY ONE OF THE BETTER PERFORMING MODELS FOR MARINE STRATUS/ DO NOT SUPPORT THIS AS THEY SHOW A DRY LAYER FROM NEAR THE SFC TO ABOUT 5KFT. THEREFORE...DON/T HAVE ENOUGH CONFIDENCE FOR FOG/DRIZZLE WITH THIS UPDATE...BU IT BEARS WATCHING ESPECIALLY GIVEN THE WEAK WARM ADVECTION WITH HIGH PRES TO THE E. LOWS WILL BE DEPENDENT ON HOW MUCH CLOUDINESS IS OBSERVED...BUT SUSPECT MINS WILL BE NEAR TO SLIGHTLY BELOW WHAT THEY HAVE BEEN THE LAST FEW NIGHTS GIVEN THE COOLER START. SAT... MID LVL RIDGING WILL FINALLY BEGIN TO BUILD TO THE E AS UPPER LVL CUTOFFS MOVE E OF THE REGION. THIS WILL ALLOW FOR THE GRADUAL DIMINISHING OF CLOUDINESS ACROSS THE REGION. COMBINE THIS INCREASED SUNSHINE WITH WARMER MID LVL TEMPS THANKS TO THE MODEST WARM ADVECTION MENTION ABOVE...AND SUSPECT WE WILL SEE WARMER TEMPS ACROSS THE REGION THAN EXPERIENCED ON FRI. WINDS WILL BE SHIFTING TO THE S...SO AWAY FROM THE COAST...WHERE SEA BREEZES ARE STILL LIKELY THANKS TO A WEAK PRES GRADIENT. WILL SEE TEMPS IN THE UPPER 60S TO LOW 70S. COOLER NEAR THE COAST THANKS TO SEA BREEZES. THERE IS A SLIGHTLY HIGHER CHANCE FOR SHOWERY ACTIVITY MAINLY ACROSS WRN MA/CT AS THE WEAK INSTABILITY TROF SHIFTS E. WILL CARRY SLIGHT CHANCE POPS FOR NOW...BUT ITS POSSIBLE THAT HIGHER POPS WILL BE NEEDED AS THIS FEATURE IS BETTER DEFINED. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... BIG PICTURE...RIDGE BUILDS OVER THE EASTERN USA WHILE GULF OF ALASKA LOW AND SOUTHERN STREAM SHORTWAVE MERGE TO FORM A CLOSED LOW WEST OF THE ROCKIES. WITH ABOVE NORMAL HEIGHTS OVER NEW ENGLAND...WE SHOULD EXPECT TEMPS AT OR ABOVE NORMAL ESPECIALLY OVER THE INTERIOR. MODEL GUIDANCE IS SUFFICIENTLY SIMILAR TO GO WITH A GENERAL BLEND OF DATA. THE DAILIES... SATURDAY NIGHT-SUNDAY...HIGH PRESSURE AXIS SHIFTS OFFSHORE BRINGING A LIGHT SOUTHWEST FLOW ACROSS NEW ENGLAND. TEMPS AND DEWPOINTS WILL BE CLOSE ENOUGH AT NIGHT FOR PATCHES OF FOG TO DEVELOP. SUNSHINE ON SUNDAY WILL BURN OFF THE FOG AND PROVIDE A FAIR WEATHER DAY. MIXING SHOULD REACH TO 800 MB WHERE TEMPS OF 2-3C WOULD SUPPORT SFC MAX TEMPS OF 68-73F. A SHORTWAVE CROSSES THE REGION DURING THE DAY. CONVECTIVE INDICES SHOW SOME CONCERN FOR SHOWERS IN THE INTERIOR DURING THE AFTERNOON. WE CONTINUE TO MENTION SLIGHT CHANCE POPS IN THE INTERIOR WITH LOW-END CHANCE POPS IN NORTHWEST MASS. MONDAY...HIGH PRESSURE IN PLACE OFFSHORE SHOULD BRING FAIR WEATHER. TEMPS ALOFT AT 9-11C WILL SUPPORT MAX SFC TEMPS IN THE MID-UPPER 70S...EXCEPT COOLER TEMPS ALONG THE SOUTH COAST. TUESDAY...UPPER SHORTWAVE SQUEEZES THE RIDGE SOUTH A LITTLE AND MOVES ACROSS NORTHERN NEW ENGLAND. WHILE MUCH OF THE DYNAMIC SUPPORT WILL BE NORTH OF OUR AREA...THIS WILL SWING A COLD FRONT ACROSS SOUTHERN NEW ENGLAND WITH LOW LEVEL CONVERGENCE. THE AIRMASS WILL BE MOIST WITH PRECIPITABLE WATER VALUES REACHING 1.4 INCHES WHICH IS ABOUT 2 STD DEVIATIONS ABOVE NORMAL. WE WILL MAINTAIN CHANCE POPS FOR SHOWERS. WEDNESDAY-THURSDAY...HIGH PRESSURE BUILDS IN WITH A RETURN TO DRIER WEATHER. TEMPS ALOFT OF 8-9C WILL BRING MAX SFC TEMPS IN THE 70S. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT-TERM /THROUGH FRIDAY NIGHT/... TODAY...MODERATE CONFIDENCE MAINLY DUE TO TIMING UNCERTAINTY. VFR THIS MORNING IN THE CT VALLEY...BUT MVFR CIGS AT WORCESTER AND RI/EASTERN MASS. EXPECT THESE CIGS TO GRADUALLY LIFT TO VFR THIS AFTERNOON. ISOLATED SHOWERS POSSIBLE...BUT FOR MOST PLACES THIS WILL BE A DRY DAY WITH NORTHEAST WINDS. TONIGHT...MODERATE CONFIDENCE. WITH CLOUDINESS STILL IN PLACE IT/S POSSIBLE SOME E COASTAL LOCATIONS DIP BACK TO MVFR/IFR UNDER LOW CIGS AND OCCASIONAL DRIZZLE. HOWEVER...IT COULD REMAIN VFR LIKE THE REST OF THE REGION. HENCE THE UNCERTAINTY. SATURDAY...HIGH CONFIDENCE. MAINLY VFR AFTER ANY LOWER CIGS/DRIZZLE DIMINISHES. WINDS SHIFT MORE TO THE SE. KBOS TAF...MODERATE CONFIDENCE IN TAF...MAINLY DUE TO UNCERTAINTY IN TIMING OF MVFR CIGS. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...MODERATE CONFIDENCE. SATURDAY NIGHT THROUGH MONDAY...VFR MOST OF THE PERIOD. LOCAL MVFR CIGS/VSBYS POSSIBLE SUNDAY IN WIDELY SCATTERED SHOWERS...MAINLY WESTERN MASSACHUSETTS. LOCAL MVFR/IFR ALSO POSSIBLE IN PATCHY FOG SUNDAY AND MONDAY EARLY MORNINGS. TUESDAY...PERIODS OF MVFR CIGS/VSBYS IN SHOWERS AS A COLD FRONT SWEEPS THROUGH. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT-TERM /THROUGH SATURDAY/... TODAY...HIGH CONFIDENCE. MAINLY E TO NE FLOW...WITH THE POSSIBILITY OF A FEW GUSTS AROUND 20 KT THIS MORNING ON THE WATERS S AND E OF THE ISLANDS/CAPE COD. SEAS BUILD TO AROUND 4 FT...BUT CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS. TONIGHT INTO SAT...LOW CONFIDENCE. CONCERN TOWARDS SATURDAY MORNING OF LOW CLOUDS WITH A MIX OF FOG AND DRIZZLE RESULTING IN SOME VISIBILITY ISSUES. LOW CONFIDENCE AT THIS TIME. WINDS AND SEAS SHOULD BE BELOW SMALL- CRAFT ADVISORY CRITERIA. SHOULD THESE LOWER VSBYS OCCUR...THEY WILL IMPROVE DURING THE DAY SAT. .OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...HIGH CONFIDENCE. WINDS AND SEAS WILL BE LESS THAN SMALL CRAFT THRESHOLDS. AREAS OF FOG WILL BRING POOR VISIBILITY TO THE WATERS SUNDAY AND MONDAY EARLY MORNING. SOUTHWEST WINDS WILL GUST TO 20 KNOTS ON TUESDAY AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT WILL BRING SCATTERED SHOWERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...WTB/DOODY NEAR TERM...WTB/BELK/DOODY SHORT TERM...DOODY LONG TERM...WTB AVIATION...WTB/BELK/DOODY MARINE...WTB/DOODY

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