Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 180746 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 346 AM EDT FRI APR 18 2014 .SYNOPSIS...
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EAST TO NORTHEAST FLOW WILL KEEP TEMPERATURES COOL ALONG COASTAL AREAS...ALONG WITH THE POSSIBILITY OF GRAY SKIES THROUGH THE AFTERNOON. A WEAKENING FRONT WILL PUSH ACROSS THE REGION ON SATURDAY. HIGH PRESSURE RETURNS INTO MONDAY WITH MODERATING TEMPERATURES. LOW PRESSURE AND A COLD FRONT WILL CROSS THE REGION TUESDAY INTO WEDNESDAY WITH THE CHANCE FOR SHOWERS. DRY AND SEASONABLE CONDITIONS ARE FORECAST INTO LATE NEXT WEEK.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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INVERTED RIDGING FROM HIGH PRES CENTER IN THE CANADIAN MARITIMES CONTINUES TO YIELD A DEEP DRY LAYER ABOVE SOME TRAPPED MOISTURE FROM THE DELMARVA TO NEW ENGLAND. THIS IS COMBINING WITH E TO NE FLOW...DRAWING AIR ACROSS THE WATERS WHERE SSTS ARE ONLY IN THE LOW 40S. WITH THIS FLOW EXPECTED TO CONTINUE UNTIL THE RIDGE SHIFTS E LATE TODAY...THE TRAJECTORY IS EXPECTED TO KEEP AREAS WITHIN BOTH THE I-495 AND I-95 CORRIDORS MUCH COLDER THAN AREAS FURTHER W. THEREFORE...EXPECT HIGHS ONLY IN THE LOW-MID 40S MAINLY E OF THESE HIGHWAYS WHILE HIGHS FURTHER W WILL BREAK INTO THE LOW- MID 50S. REGARDING MARINE SC AND DRIZZLE CHANCES...MODELS STRUGGLING TO INITIALIZE CURRENT BAND OF SC S OF LI AND INTO NJ AND CONTINUES TO TRY AND DEVELOP ANOTHER BAND E OF MASS BAY. HOWEVER...AM NOTING THAT DWPT DEPRESSIONS IN THE LOW LVLS ARE A BIT WIDER THAN GUIDANCE CURRENTLY SHOWING AND WINDS HAVE BEEN MORE N OF E. CMC REGIONAL BL SETUP DOES STILL SUGGEST SC FORMS E OF MASS BAY AROUND 12Z...SLIDING INLAND THROUGH THE MORNING HOURS...AND IT IS THE ONLY MODEL HANDLING CURRENT BAND S OF LONG ISLAND. GIVEN ALL OF THESE PROS/CONS REGARDING THE SC DEVELOPMENT...DIMINISHED THE COVERAGE BUT CONTINUED TO HIGHLIGHT THE POSSIBILITY UNTIL WINDS SHIFT MORE TO THE W BY LATE IN THE DAY IN ADVANCE OF A WEAKENED COLD FRONT. HOWEVER...SHOULD NOTE THE CONFIDENCE IS NOT ALL THAT HIGH ON WHETHER IT OCCURS AT ALL...OR ITS EXACT TIMING.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
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TONIGHT... SFC COLD FRONT WILL BE RAPIDLY SLIDING ACROSS THE AREA DURING THE OVERNIGHT HOURS. HOWEVER...SOUNDINGS SHOW MOISTURE LAYER REMAINS MAINLY ABOVE H6...WITH DWPT DEPRESSIONS EXCEEDING 10C FROM THE SFC TO H6. LOW-MID LVL F-GEN IS ALSO VERY WEAK AS IT ARRIVES GIVEN IT IS TRYING TO PUSH THROUGH RIDGING. THEREFORE...EXPECT LITTLE FANFARE WITH THIS FRONTAL PASSAGE EXCEPT MID-HIGH CLOUDINESS AND W WINDS INCREASING THROUGH SUNRISE. CONTINUE TO SUGGEST NIL POPS. BKN-OVC CLOUDS WILL KEEP MINS WARMER THAN PREVIOUS NIGHTS...BUT ANOMALOUSLY COOL AIRMASS SUGGESTS TEMPS STILL DROP TO THE LOW-MID 30S. SAT... HIGH PRES REGAINS CONTROL WITH COLD ADVECTION TO START THE DAY. THIS COLD ADVECTION WILL ALLOW MIXING UNDER ONLY PARTLY CLOUDY SKIES TO REACH HIGHER THAN H8...WHERE TEMPS ONLY DIP TO AROUND -1C. COMBINE THIS WITH W DOWNSLOPE FLOW...AND TEMPS SHOULD BE ABLE TO REBOUND INTO THE LOW 60S. LOW CHANCE OF A SEA BREEZE GIVEN H92 WINDS REACH AROUND 20-25 KT. THEREFORE...ALSO EXPECT WINDS AROUND 20 MPH THROUGH THE DAY.
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&& .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGHLIGHTS... * DRY AND SEASONABLE THROUGH MONDAY * SHOWERS FORECAST FOR TUESDAY INTO WEDNESDAY OVERVIEW AND MODEL PREFERENCES/CONFIDENCE... NOTING MEDIUM RANGE MODELS CONTINUE TO SIGNAL A FLAT...SPLIT FLOW SURFACE AND UPPER LEVEL REGIME ACROSS THE LOWER 48 INTO EARLY NEXT WEEK...KEEPING FAST MOVING WEAK SYSTEMS ACROSS THE NORTHERN TIER STATES. BY AROUND SUNDAY...MODELS ARE SIGNALING AN H5 CUTOFF LOW DEVELOPING OFF THE SE U.S...WHICH COULD BRING A CHANGE IN THE OVERALL UPPER LEVEL FLOW AROUND THE MIDDLE OF NEXT WEEK. SOME QUESTIONS AS TO THE TIMING OF THIS FEATURE AND WHEN IT WILL MOVE OFFSHORE. BY THE MIDDLE OF NEXT WEEK...LOOKS LIKE A MORE AMPLIFIED LONG WAVE PATTERN DEVELOPS AS AN H5 SHORT WAVE DIGS OUT OF CENTRAL CANADA AND THE GREAT LAKES. THIS LOOKS TO ARRIVE AROUND THE TUE- WED TIMEFRAME...WHICH SIGNALS A PERIOD OF UNSETTLED WEATHER FOR THE REGION. ANOTHER CUTOFF LOW ALSO LOOKS TO DEVELOP ACROSS THE NORTHERN ROCKIES LATE IN THE PERIOD...WHICH MAY LEAD TO A SLOWING OF THE PROGRESSION OF SYSTEMS. USED A BLEND OF THE ENSEMBLE MEANS AND PREVIOUS FORECAST...ALL OF WHICH ARE IN GOOD AGREEMENT FOR MOST OF THIS FORECAST PERIOD. DETAILS... SATURDAY... EXPECT A DRY...WEAK FRONT TO CROSS THE REGION DURING THE DAY. WENT WITH A DRY FORECAST...AS THERE IS LITTLE IF ANY MOISTURE ASSOCIATED WITH THIS FEATURE EMBEDDED IN THE DRY WESTERLY UPPER FLOW. WINDS WILL SHIFT TO NW DURING THE AFTERNOON BUT...WITH A LIGHT PRES GRADIENT...NOT EXPECT THEM TO BECOME TOO GUSTY. HIGHS WILL RANGE FROM THE MID 50S TO LOWER 60S. WITH MOSTLY CLEAR SKIES AND LIGHT N WINDS...EXPECT OVERNIGHT LOWS WILL DROP TO THE UPPER 20S ACROSS SW NH INTO N CENTRAL AND W MA... POSSIBLY AS FAR S AS THE SPRINGFIELD AREA...RANGING TO THE UPPER 30S TO AROUND 40 ALONG THE IMMEDIATE S COAST. THESE COLDER INTERIOR READINGS WILL RUN AROUND 5 DEGREES BELOW SEASONAL NORMALS. SUNDAY AND MONDAY... CONTINUED HIGH CONFIDENCE FOR DRY AND SEASONABLE CONDITIONS ACROSS THE REGION AS HIGH PRES BECOMES CENTERED ACROSS NEW ENGLAND. WILL BE SOMEWHAT COOLER ALONG E COASTAL AREAS AS THE ORIENTATION OF THE N-S RIDGE AXIS WILL KEEP AN E-NE WIND FLOW IN PLACE. IT WILL REMAIN RATHER CHILLY ALONG THE COAST ON SUNDAY WITH HIGHS ONLY IN THE LOWER- MID 50S...EVEN SOME UPPER 40S ON THE OUTER CAPE AND NANTUCKET...BUT WILL MODERATE SOMEWHAT BY MONDAY AS THE RIDGE NARROWS AS IT SETTLES S. HIGHS MONDAY WILL REMAIN COOLER ACROSS THE OUTER CAPE AND NANTUCKET TO THE IMMEDIATE S COAST...TOPPING OFF IN THE LOWER-MID 50S...BUT RANGING TO THE 60S ELSEWHERE. SOME HIGH CLOUDS MAY BEGIN TO FILTER IN LATER SUN NIGHT INTO MON ACROSS CENTRAL AND NORTHERN AREAS. MONDAY NIGHT THROUGH WEDNESDAY... MODELS CONTINUE TO SIGNAL THIS TO BE AN UNSETTLED PERIOD AS BROAD LOW PRES AND ITS ASSOCIATED COLD FRONT WORK OUT OF THE GREAT LAKES. SOME QUESTION AS TO THE ARRIVAL OF PRECIP...LOOKS TO BE A BIT SLOWER THAN PREVIOUSLY FORECAST. MAY SEE SCT SHOWERS MOVE INTO S NH/NW MA WELL AFTER MIDNIGHT MON NIGHT. BEST SHOT OF PRECIP WILL BE THE TUESDAY INTO WEDNESDAY MORNING TIMEFRAME AS THE FRONT TENDS TO SLOW DOWN AS IT MOVES ACROSS THE REGION...IN RESPONSE TO CUTOFF LOW PRES TRYING TO EXIT OFF THE SE U.S. COAST. MIGHT SEE BEST QPF VALUES INTO THE TUE NIGHT TIMEFRAME AS MODELS ARE TRYING TO SIGNAL A WEAK WAVE MOVING ALONG THE FRONT... POSSIBLY BRINGING A DECENT SHOT OF PRECIP INTO CENTRAL AND EASTERN AREAS. SOME DISPARITY AS TO WHERE THIS WILL OCCUR. KEPT POPS ON HIGH END CHANCE CATEGORY...BUT FEEL HIGHEST WILL BE MAINLY ACROSS CENTRAL AND EASTERN MA INTO RI FOR NOW. EXPECT HIGHS ON TUESDAY TO BE MAINLY IN THE 60S...EXCEPT 50S ALONG IMMEDIATE S COAST...BUT ONLY IN THE 50S TO LOWER 60S DURING WED WITH CLOUD COVER AND PRECIP. CURRENT TIMING SUGGESTS BACK EDGE OF PRECIP SHOULD START TO SHIFT INTO WESTERN AREAS DURING WED AFTERNOON. WEDNESDAY NIGHT-THURSDAY... SOME TIMING ISSUES ON THE OPERATIONAL MODEL RUNS...BUT LOOKS TO BE DRYING OUT FROM W-E EARLY WED NIGHT...THEN HIGH PRES BUILDS IN OUT OF CENTRAL CANADA FOR THURSDAY. SOMEWHAT LOWER CONFIDENCE DURING THIS TIMEFRAME DUE TO TIMING. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE THROUGH TONIGHT...HIGHER CONFIDENCE INTO SAT... THERE IS THE CHANCE OF ANOTHER ROUND OF MVFR CIGS WRAPPING INTO AREAS S AND E OF A WST-PVD-BOS LINE. LOWER CONFIDENCE ON EXACTLY HOW DEEP IT GETS...BUT ONCE IT OCCURS IT WILL LIKELY LINGER INTO AT LEAST THE EARLY AFTERNOON AS NE WINDS VEER TO THE E. OUTSIDE OF THIS LINE...MAINLY VFR IS EXPECTED. BY LATE THIS AFTERNOON...WINDS W OF THE LINE SHIFT FROM THE S TO W AND WINDS E OF THE LINE BEGIN TO SHIFT TO THE S...SO ANY LINGERING MVFR CIGS SHOULD BEGIN TO SCT OUT. AFTER THAT MAINLY VFR IS EXPECTED OVERNIGHT INTO SAT ALTHOUGH WITH INCREASING HIGH AND MID CLOUDS DURING THE OVERNIGHT AND EARLY MORNING HOURS. ALTHOUGH THERE IS THE LOW PROBABILITY OF SOME MVFR/IFR FOG BEFORE WINDS SHIFT TO THE W AT COASTAL TERMINALS EARLY SAT MORNING. WINDS THEN SHIFT TO THE W SAT MORNING WITH WNW WIND GUSTS AROUND 20 KT BY MID DAY SAT. KBOS TERMINAL...MODERATE CONFIDENCE. MAIN ISSUE IS WHETHER AND FOR HOW LONG MVFR CIGS REMAIN IN PLAY LATER THIS MORNING. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SATURDAY NIGHT THROUGH MONDAY...HIGH CONFIDENCE. VFR. MONDAY NIGHT AND TUESDAY...MODERATE CONFIDENCE. VFR TO START. MAY SEE LOCAL MVFR IN SCT SHOWERS MOVING INTO S NH AND CENTRAL-W MA AFTER MIDNIGHT. WILL SEE AREAS OF LOW END MVFR CIGS/VSBYS THROUGH TUESDAY AS FRONT SLOWLY CROSSES THE REGION. && .MARINE...
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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 SATURDAY/...HIGH CONFIDENCE. ALTHOUGH WINDS EACH DAY ARE EXPECTED TO REMAIN BELOW THE 25 KT THRESHOLD FOR SMALL CRAFT ADVISORY...A LINGERING SWELL WILL KEEP SEAS AT LEAST 5-7FT THROUGH THE DAY ON SAT ON THE OCEAN WATERS ESPECIALLY. THEREFORE WILL TRANSITION TO SMALL CRAFT FOR HAZ SEAS ACROSS THE WATERS INTO 12Z SAT AT LEAST...WITH NEAR SHORE WATERS DROPPING EARLIER. WINDS TODAY BEING OUT OF THE N-NE...SHIFTING TO THE SW TONIGHT THEN W DURING THE DAY ON SAT. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SUNDAY...NE WINDS RETURN ACROSS THE WATERS AS HIGH PRES BUILDS TO THE N. GUSTS UP TO 20 KT EARLY. SEAS LINGER AROUND 5 FT ON THE EASTERN OUTER WATERS...THOUGH MAY SUBSIDE SUN NIGHT. MONDAY AND TUESDAY...EXPECT WINDS TO SHIFT FROM SE TO S-SW BUT REMAIN LIGHT...GENERALLY 15 KT OR LESS THROUGH THIS TIMEFRAME. MAY SEE SOME GUSTS UP TO 20 KT LATER TUESDAY. SEAS BELOW SMALL CRAFT CRITERIA.
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&& .HYDROLOGY...
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MINOR FLOODING CONTINUES ALONG PORTIONS OF THE MAIN STEM CT RIVER. MOST POINTS HAVE REACHED CREST...BUT WILL TAKE MORE TIME TO DROP BELOW FLOOD STAGE. THE RIVER HAS DROPPED BELOW FLOOD STAGE AT MONTAGUE...AND IS NOT EXPECTED TO REACH MODERATE FLOOD ANY LONGER AT MIDDLE HADDAM. FLOOD WARNINGS REMAIN POSTED ALONG CT RIVER AT... NORTHAMPTON THOMPSONVILLE HARTFORD MIDDLE HADDAM
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ232. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EDT THIS AFTERNOON FOR ANZ235-237. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT SATURDAY FOR ANZ250-251-254>256.
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&& $$ SYNOPSIS...FRANK/DOODY NEAR TERM...DOODY SHORT TERM...DOODY LONG TERM...FRANK AVIATION...FRANK/DOODY MARINE...FRANK/DOODY HYDROLOGY...

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