Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 230517 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 117 AM EDT SAT MAY 23 2015 .SYNOPSIS... A COLD FRONT WILL MOVE OFFSHORE TONIGHT...USHERING IN UNSEASONABLY COLD AIR WITH AREAS OF FROST...ESPECIALLY IN WESTERN MASSACHUSETTS. GRADUAL WARMING IS EXPECTED THROUGH NEXT WEEK...LEADING TO HOT AND HUMID CONDITIONS BY MID WEEK. THERE IS THE LOW CHANCE FOR A SHOWER OR THUNDERSTORM MONDAY THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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115 AM UPDATE... PATCHY MID CLOUDS MOVING OFF S COAST AND THRU CENTRAL NEW ENGLAND...OTHERWISE CLEAR SKIES PREVAIL. WINDS HAVE DIMINISHED ACROSS PARTS OF INTERIOR BUT STILL SEEING DECENT MIXING OVER MOST OF AREA...ESPECIALLY NEAR COAST. THIS WILL LEAD TO WIDE RANGE IN TEMPERATURES BY DAYBREAK. AM FAIRLY CONFIDENT IN FROST/FREEZE WHERE HEADLINES ARE CURRENTLY IN PLACE...AND LESS SO ACROSS USUAL COLD SPOTS IN INTERIOR E MA. MADE SOME ADJUSTMENTS TO OVERNIGHT LOWS TO REFLECT THIS TREND.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... HIGHER PRESSURE OVER THE MID ATLANTIC STATES GRADUALLY INCREASES ITS INFLUENCE ON OUR WEATHER SATURDAY INTO SATURDAY NIGHT. WITH THIS HIGH PRESSURE REMAINING TO OUR SOUTH...WE WILL SEE A CONTINUATION OF A GENERALLY WEST WIND. PRESENT THINKING IS THIS FLOW WILL BE STRONG ENOUGH TO PREVENT SEABREEZES FROM DEVELOPING. UNSEASONABLE COLD CONTINUES...WITH HIGH TEMPERATURES SATURDAY ONLY RECOVERING INTO THE LOWER TO MID 60S AT MOST. MORE SEASONABLE TEMPERATURES ARE EXPECTED FOR SATURDAY NIGHT LOW TEMPERATURES. DRY WEATHER CONTINUES. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... - SOME SHOWERS POSSIBLE OVER THE INTERIOR MONDAY...BUT HIT-OR-MISS - GRADUAL WARMING LEADS TO HOT AND HUMID CONDITIONS BY MID WEEK. OVERVIEW AND MODEL PREFERENCES... WITH 22.12Z MODEL GUIDANCE CONTINUING TO CONVERGE ON A SOLUTION... AGREE WITH THE LATEST CPC OUTLOOK THAT WARMER THAN USUAL WEATHER WILL RETURN AFTER A COOL START THIS WEEKEND. PREVIOUS SHIFT FORECASTER NOTED THAT THERE IS NOW MUCH BETTER AGREEMENT THAT BERMUDA HIGH AND IT/S SUBTROPICAL RIDGE ARE LIKELY TO GAIN CONTROL OVER THE REGION THROUGH AT LEAST MID WEEK AS LONGWAVE TROF CONTINUES TO RECEDE BACK INTO NE QUEBEC/LABRADOR. THEREFORE... WILL BE CONTINUING THIS TREND THANKS TO BETTER CONFIDENCE IN THE LATEST RUN SOLUTIONS. KIND OF LIKE THE CMC/ECMWF AS A BLEND TO START GIVEN THEIR BETTER CONSISTENCY AND SLIGHTLY LOWER AMPLIFIED SOLUTIONS. HOWEVER...THIS MASS FIELD RIDGE IS ACCOMPANIED BY FAIRLY ROBUST THETA-E RIDGE WITH PWATS NEARLY 3 STD DEVIATIONS ABOVE NORMAL. TO QUOTE W.B. YEATS...THE CENTRE CANNOT HOLD...A DESTABILIZED COLUMN COULD YIELD DIURNAL CONVECTION PARTICULARLY AS A WEAKENING CUTOFF LOW PRES CURRENTLY OVER THE ROCKIES SHIFTS E BY TUE-WED. NEAR NEUTRAL AO/NAO ALSO SUGGEST THE BLOCK WON/T HOLD UP. DETAILS... SUN...MAINLY A REBOUND DAY. THE COLDER TEMPS OF SAT WILL BE GIVING WAY TO MORE MODERATE...SEASONAL TEMPERATURES. H85 TEMPS WILL BE REACHING THE NEAR NORMAL VALUES OF +8C TO +10C. SW WINDS WILL PROMOTE SOME DOWNSLOPING SO WARMER LOCALES OF WRN MA/CT WILL LIKELY APPROACH 80...WHILE THE REMAINING LOCALES REMAIN IN THE 70S. THIS MODERATE W FLOW IS LIKELY ALSO TO LIMIT SEA BREEZE DEVELOPMENT. MON...AS THE UPPER RIDGE BEGINS IT/S BUILDING PROCESS LLJ AND ATTENDANT SFC WARM FRONT WILL BE NOSING IN FROM THE W ON THE PERIPHERY OF THIS RIDGE. SUSPECT ENOUGH MOISTURE CONVERGENCE /PWATS INCREASE TO NEARLY 1.0 INCHES/ AND LIFT ASSOCIATED WITH THIS FEATURE TO YIELD A RISK FOR AFTERNOON -SHRA DEVELOPMENT MAINLY ACROSS INTERIOR WRN MASS/CT. ECHO PREVIOUS FORECASTER THAT IT IS UNLIKELY TO BE A WASHOUT...AND CIPS ANALOGS CONTINUE TO KEEP THE BULK OF THE ACTION TO THE NW. H85 TEMPS WILL INCREASE TO +10C OR +12C...BUT A LITTLE WEAKER MIXING WITH INCREASING CLOUD COVER AHEAD MAY KEEP AMBIENT TEMPS NEAR SEASONAL...BUT WITH INCREASED HUMIDITY AS THE BUILDING THETA-E RIDGE SUGGESTS DWPTS HEADING INTO THE 50S. TUE AND WED...THINGS START TO GET TRICKY HERE. PEAK THETA-E RIDGING AND SLIGHT COOLING AT H5 ARE LIKELY TO YIELD MODERATE MID LVL LAPSE RATES WITHIN THE WARM SECTOR. BUFKIT PROFILES DENOTE VERY HIGH PWATS /NEAR 1.75 INCHES/ ALONG WITH SFC BASED INSTABILITY 500- 1000 J/KG EACH AFTERNOON. STRONGER LLJ AND UPPER LVL DIVERGENCE REMAIN TO THE NW ON TUE...SO SUSPECT MOST CONVECTIVE ACTIVITY REMAINS NW. ON WED...RELOADING OF THE PATTERN AND SECONDARY RIDGE BUILDING BEHIND THE TUE SHORTWAVE MAY MITIGATE AFTERNOON CONVECTIVE ACTIVITY IN SPITE OF THE DESTABILIZED PROFILE. GIVEN THE DIURNALLY DRIVEN INSTABILITY BUT WITH MITIGATING FACTORS...WILL INCREASE POPS TO LOW END CHANCE IN THE W EACH AFTERNOON AS IT/S LIKELY TO BE MORE HIT OR MISS. RETURN FLOW...WITH W COMPONENT AND WARMING MID LVL TEMPS ALL SUGGEST CONTINUOUS TEMPERATURE MODERATION. HIGHS MAY APPROACH THE 90F IN WARM SPOTS. DWPTS IN THE LOW-MID 60S SUGGEST UNCOMFORTABLE HUMIDITY. THU AND FRI...ONCE AGAIN A TRICKY FORECAST HERE. IN THIS CASE...BETTER LOW LVL FORCING IS EXPECTED IN THE FORM OF A MORE ROBUST MID LVL SHORTWAVE AND ATTENDANT COLD FRONTAL PASSAGE. HOWEVER...AT ISSUE IS THE REBOUNDING RIDGE MENTIONED EARLY. THIS WILL LEAD TO AN OVERALL WEAKENING OF THE COLD FRONT/TROF SYSTEM. BUFKIT DOES SHOW SIGNS OF A SUBSIDENCE INVERSION IN PLACE WHICH COULD PRECLUDE AFTERNOON CONVECTION. INSTABILITY STILL SOMEWHAT FAVORABLE...BUT THIS IS A WEEK OUT. WILL NEED TO CONTINUE TO WATCH THIS PERIOD SHOULD THE FRONT SLOW TO A NEAR STALL AS IT INTERACTS WITH THE BUILDING RIDGE. PROVIDING A NEAR STEADY SOURCE OF LIFT FOR THE DESTABILIZED ATMOSPHERE. && .AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH SUN. W/NW WINDS GUST TO 20-25 KT THROUGH MIDDAY...BEFORE WINDS BACK TO W/SW AND DIMINISH THIS AFTERNOON AND TONIGHT. SW WINDS GUST TO 20-25KT SUN...ESPECIALLY NEAR S COAST. VFR THROUGH PERIOD. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. W/NW FLOW. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...SUNDAY THROUGH WEDNESDAY... MONDAY...HIGH CONFIDENCE. VFR. MAINLY LIGHT W-SW WINDS...WITH SEA BREEZES LIKELY. LOW CHANCE FOR A SHOWER IN WRN MA/CT MON AFTERNOON AND EVENING. TUE AND WED...HIGH CONFIDENCE. MAINLY VFR. ALTHOUGH SOME OVERNIGHT FOG AND STRATUS IS POSSIBLE NEAR COASTLINES...THIS COULD LEAD TO LOCALIZED IFR/MVFR. ALSO...SW FLOW DOMINATES. LOW CHANCE EACH AFTERNOON/EVENING FOR AFTERNOON SHOWERS/TSRA MAINLY IN THE FAR INTERIOR.
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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 SATURDAY NIGHT/... COLD FRONT MOVING OFFSHORE WILL BRING INCREASING NW WINDS TO WATERS WITH GUSTS UP TO 25KT. SCA REMAINS POSTED. WINDS DIMINISH SAT AFTERNOON AS HIGH PRES BUILDS OVER WATERS AND REMAINS BELOW SCA THROUGH SAT NIGHT WITH DIMINISHING SEAS. OUTLOOK...SUNDAY THROUGH WEDNESDAY... SUNDAY AND MONDAY...HIGH CONFIDENCE. HIGH PRES WILL MOVE OVER THE WATERS YIELDING PERIOD OF MAINLY QUIET BOATING WEATHER. TUESDAY AND WEDNESDAY...MODERATE CONFIDENCE. WINDS SHIFT TO THE SW...AND INCREASE WITH A FEW NEAR SHORE GUSTS BETWEEN 20 AND 25 KT. EXPECT A SLOWLY BUILDING SW SWELL. THERE MAY BE A NEED FOR SMALL CRAFT ADVISORIES THROUGH THIS PERIOD...BUT NOT THE ENTIRE TIME. SOME MARINE STRATUS AND FOG MAY DEVELOP...REDUCING VISIBILITIES. && .FIRE WEATHER... VERY DRY CONDITIONS EXPECTED SATURDAY...ALONG WITH GUSTY WEST WINDS. WITH THE LACK OF APPRECIABLE RAINFALL ACROSS SOUTHERN NEW ENGLAND LAST NIGHT...AND INFORMATION FROM STATE FIRE OFFICIALS...WILL ISSUE A STATEMENT CONCERNING AN ELEVATED RISK FOR FIRE SPREAD ACROSS SOUTHERN NEW ENGLAND. && .CLIMATE... RECORD LOWS FOR MAY 23RD... BOSTON - 40 /1967/ HARTFORD - 37 /1976/ PROVIDENCE - 40 /1950/ WORCESTER - 32 /1929/ && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...FROST ADVISORY UNTIL 7 AM EDT THIS MORNING FOR MAZ004-009>011- 026. FREEZE WARNING UNTIL 7 AM EDT THIS MORNING FOR MAZ002-003-008. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR ANZ231>235-237-250-251-254>256. SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ230- 236.
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&& $$ SYNOPSIS...BELK/DOODY NEAR TERM...JWD SHORT TERM...BELK LONG TERM...DOODY AVIATION...JWD MARINE...BELK/DOODY FIRE WEATHER...BELK CLIMATE...STAFF

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