Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 301355 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 955 AM EDT THU OCT 30 2014 .SYNOPSIS... HIGH PRESSURE WILL BRING DRY AND SEASONABLE CONDITIONS THROUGH THE END OF THE WORK WEEK. A COASTAL STORM WILL LIKELY DELIVER A GLANCING BLOW TO THE REGION LATE SATURDAY INTO SUNDAY...BUT THE OPPORTUNITY FOR A HIGHER IMPACT STILL EXISTS. MAINLY DRY WEATHER FOLLOWS WITH A SIGNIFICANT WARMING TREND BY NEXT TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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10 AM UPDATE...MADE SOME CHANGES TO THE SKY FORECAST BASED ON THE LATEST SATELLITE IMAGERY. OTHERWISE...FORECAST IS ON TRACK. PREVIOUS DISCUSSION... FOR TODAY...EXPECT DRY CONDITIONS AS WEAK HIGH PRES APPROACHES FROM THE WEST DURING THE DAY AS H5 SHORT WAVE CROSSES THE REGION...PUSHING OFFSHORE BY MIDDAY. H85 TEMPS DO FALL DURING THE DAY...THOUGH LOOKS LIKE THE CORE OF THE COLD AIR REMAINS TO THE N. TEMPS WILL BE SEASONABLE FOR LATE OCTOBER...TOPPING OFF IN THE 50S. EXPECT LIGHT W-NW WINDS WITH A LIGHT PRES GRADIENT ACROSS THE REGION.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... TONIGHT... EXPECT THE WEAK HIGH PRES RIDGE TO BUILD E ACROSS NORTHERN NEW ENGLAND TONIGHT. LIGHT N WINDS WILL BE IN PLACE WHICH WILL VEER TO NE AFTER MIDNIGHT. MAY SEE SOME MORE PATCHY FOG DEVELOP IN THE NORMALLY PRONE VALLEY AREAS. NOTING LOW PRES OVER THE GREAT LAKES TONIGHT AS A DIGGING H5 SHORT WAVE DIVES SE. SW FLOW ALOFT REMAINS IN PLACE...SO COULD SEE SOME MID AND HIGH CLOUDS WORK INTO WESTERN AREAS AFTER MIDNIGHT. WITH THE COLDER AIR WORKING IN ALONG WITH A GENERAL LIGHT WIND IN PLACE...EXPECT LOWS FALLING BACK TO THE 30S FOR MOST AREAS...RANGING TO LOWER-MID 40S ALONG THE IMMEDIATE COAST. WILL NEED TO MONITOR FOR FROST/FREEZE HEADLINES MAY BE NECESSARY FOR S/E COASTAL MA AND RI. FRIDAY... MAJOR DIGGING H5 LONG WAVE TROUGH/CUTOFF LOW TAKES SHAPE ACROSS THE OHIO VALLEY INTO THE CENTRAL GREAT LAKES...WHICH SETS UP AN INCREASING SW FLOW ALOFT ALONG THE EASTERN SEABOARD. HOWEVER...AT THE SURFACE...GENERAL LIGHT FLOW CONTINUES THOUGH E-NE WINDS WILL BEGIN TO FRESHEN DURING THE AFTERNOON ALONG THE S COAST. BIG QUESTION AT THIS POINT...WHERE LOW PRES DEVELOPS OFF THE MID ATLC OR SE U.S. COAST FRI AFTERNOON. EXPECT CLOUDS TO INCREASE WITH THE INCREASING LOW LEVEL ONSHORE FLOW IN PLACE. THIS WILL HOLD TEMPS BACK. HIGHS WILL ONLY REACH THE UPPER 40S ACROSS THE HIGHER TERRAIN OF SW NH/W MA...RANGING TO THE LOWER-MID 50S ELSEWHERE. AT THIS POINT...NOT EXPECTING ORGANIZED PRECIP DURING THE DAY ON FRIDAY AS BEST LIFT AND MOISTURE REMAINS S OF THE REGION. HOWEVER...COULD SEE SOME OCEAN INDUCED LIGHT SPRINKLES OR EVEN SOME COASTAL DRIZZLE. DID NOT MENTION THIS FOR NOW. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGHLIGHTS... * GLANCING BLOW MOST LIKELY SAT/EARLY SUNDAY...BUT GREATER IMPACT STILL POSSIBLE * BIGGEST CONCERN IS STRONG WINDS THIS WEEKEND ESPECIALLY CAPE COD * ACCUMULATING SNOW IS STILL POSSIBLE...BUT A LOW PROBABILITY * MUCH MILDER WEATHER RETURNS BY NEXT TUESDAY AND WEDNESDAY OVERVIEW...30/00Z GUIDANCE HAD COME INTO BETTER AGREEMENT REGARDING THEIR HANDLING OF A SIGNIFICANT COASTAL STORM THIS WEEKEND. THERE ARE A FEW ENSEMBLE MEMBERS THAT SUGGEST A CLOSER TRACK TO SOUTHERN NEW ENGLAND REMAINS POSSIBLE...BUT NOT VERY LIKELY. THE PREDOMINANT SIGNAL IS FOR A TRACK REMAINING SOUTH AND EAST OF THE 40N/70W BENCHMARK. WILL FAVOR A CONSENSUS BLEND TO SMOOTH OVER AS MANY MINOR DIFFERENCES AS POSSIBLE. DETAILS... SATURDAY AND SUNDAY... FORECAST CONFIDENCE IN THE DETAILS REMAINS MODERATE FOR THIS TIME PERIOD. THE BIGGEST CONCERN REMAIN POTENTIAL FOR STRONG TO PERHAPS DAMAGING WINDS...ESPECIALLY ACROSS THE CAPE AND NANTUCKET. THERE ARE TWO MAIN SHORTWAVES INVOLVED IN THIS STORM/S FORMATION. INITIALLY...MOST MODELS FORM AN ELONGATED LOW PRESSURE SYSTEM OR EVEN TWO CENTERS BEFORE CONSOLIDATING INTO A SINGLE PRIMARY STORM. CURRENT INDICATIONS ARE THAT THIS HAPPENS TOO LATE FOR A SIGNIFICANT RAIN/SNOW EVENT IN SOUTHERN NEW ENGLAND. PRECIPITATION TYPE AND TIMING...A LOT OF THIS WILL DEPEND ON HOW FAR WEST THE MAIN PRECIPITATION SHIELD REACHES. MOST OF THE FRONTOGENETICAL FORCING IS EXPECTED TO REMAIN OFFSHORE...WHICH WOULD ALSO SUGGEST A RATHER SHARP WESTERN EDGE TO THE PRECIPITATION SHIELD. MINOR WOBBLES IN THE TRACK...COULD HAVE A SIGNIFICANT IMPACT ON WHERE THIS EDGE TO THE PRECIPITATION ESTABLISHES ITSELF. INITIALLY...ALL PRECIPITATION WILL BE IN THE FORM OF RAIN OR JUST SCATTERED SHOWERS SATURDAY. IN FACT...MOST OF THE PRECIPITATION WILL BE OVER EASTERN NEW ENGLAND...WITH JUST A FEW SHOWERS ACROSS WESTERN SECTIONS IF THE CURRENT TRACK VERIFIES. IF THIS TRACK SHIFTS WEST AND WE END UP GETTING INTO HEAVIER PRECIPITATION SATURDAY NIGHT AND EARLY SUNDAY...DYNAMIC COOLING COULD RESULT IN SOME SNOW ACROSS THE HIGHER TERRAIN. AGAIN...BASED ON THE CURRENTLY EXPECTED TRACK...ACCUMULATING SNOW IS A RATHER LOW PROBABILITY. REGARDLESS...MOST PRECIPITATION SHOULD HAVE EXITED OUR REGION BY MID MORNING SUNDAY. STRONG WINDS... STRONG WINDS ARE THE ONE THING WE ARE FAIRLY CONFIDENT THAT WILL DEVELOP. EXCELLENT MIXING ON THE BACKSIDE OF THIS STORM SHOULD RESULT IN NORTH TO NORTHWEST WIND GUSTS OF 40 TO 50 MPH DEVELOPING LATE SATURDAY AND ESPECIALLY SUNDAY AS MIXING INCREASES. ACROSS CAPE COD AND NANTUCKET...DEPENDING ON THE TRACK OF THIS STORM...WE MAY SEE A PERIOD OF 50 TO 60 MPH WIND GUSTS. WIND ADVISORIES MAY BE NEEDED FOR MUCH OF THE REGION AND PERHAPS HIGH WIND WATCHES/WARNINGS FOR THE CAPE AND NANTUCKET. GIVEN MANY TREES STILL HAVE AT LEAST SOME LEAVES ON THEM...THE RISK FOR TREE DAMAGE AND ISOLATED POWER OUTAGES WILL BE ENHANCED. MONDAY THROUGH WEDNESDAY... DEEP UPPER TROUGH LIFTS NORTHEAST OF THE REGION AND WE ENTER AN AREA OF UPPER LEVEL RIDGING. A SIGNIFICANT WARMING TREND EXPECTED WITH SOME OF THE COASTAL PLAIN POSSIBLY SEEING HIGHS BREAK 60 BY TUESDAY OR WEDNESDAY. MAINLY DRY WEATHER OVER THIS TIME...BUT A SPOT SHOWER OR TWO IS POSSIBLE...ESPECIALLY TOWARD WEDNESDAY. && .AVIATION /14Z THURSDAY THROUGH MONDAY/...
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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 FRIDAY/...HIGH CONFIDENCE THROUGH TONIGHT...THEN MODERATE CONFIDENCE FRIDAY. TODAY...VFR. SCT-BKN CLOUDS 4-5KFT THROUGH THIS AFTERNOON. TONIGHT...VFR. INCREASING CLOUDS AFTER MIDNIGHT. MAY SEE LOCAL MVFR-IFR ACROSS SW NH INTO NW MA LATE. SHALLOW PATCHY GROUND FOG POSSIBLE AT PRONE TERMINALS. FRIDAY...MAINLY VFR. WINDS SHIFT TO E-NE DURING DAY...INCREASING ALONG COAST TO 10-15 KT WITH SOME GUSTS TO 20 KT LATE IN DAY. MAY SEE MVFR CIGS DEVELOP ALONG E COAST TERMINALS DURING THE AFTERNOON. WIDELY SCT SHOWERS ALONG S COAST POSSIBLE LATE. KBOS...HIGH CONFIDENCE IN TAF. KBDL...HIGH CONFIDENCE IN TAF. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY... FRIDAY NIGHT...MODERATE CONFIDENCE. VFR TO START BUT ONSHORE FLOW MAY RESULT IN MVFR CIGS DEVELOPING. A SPOT SHOWER OR TWO POSSIBLE. SATURDAY AND SUNDAY...MODERATE CONFIDENCE. STILL SOME UNCERTAINTY WITH THE TRACK OF A LOW PRESSURE. MOST LIKELY SCENARIO IS VFR TO BE MIXED AT TIMES WITH MVFR LATE SATURDAY INTO SATURDAY NIGHT. LOWER CONDITIONS MOST LIKELY ALONG THE COAST WITH RAIN OR SCATTERED SHOWERS. LOW PROBABILITY FOR A CHANGE TO SNOW AT THE END. CONDITIONS IMPROVE TO VFR BY LATE SUNDAY...BUT NORTH TO NORTHWEST WIND GUSTS OF 30 TO 40 KNOTS EXPECTED. STRONGEST WINDS ACROSS CAPE COD AND NANTUCKET WITH GUSTS OF 40 TO 50 KNOTS POSSIBLE. MONDAY...HIGH CONFIDENCE. VFR.
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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 FRIDAY/...HIGH CONFIDENCE. TODAY...SEAS WILL CONTINUE TO SUBSIDE ACROSS THE OUTER WATERS E AND S OF CAPE COD THIS MORNING. EXPECTING WINDS AND SEAS BELOW SMALL CRAFT CRITERIA. TONIGHT...LIGHT NE WINDS AND SEAS UP TO 3 FT. FRIDAY...WINDS BECOME E-NE BUT WILL REMAIN BELOW SMALL CRAFT CRITERIA. SEAS SLOWLY INCREASE TO 3 FT ON SOUTHERN OUTER WATERS. OUTLOOK...FRIDAY NIGHT THOUGH MONDAY... ***STORM FORCE WIND GUSTS AND 20 FOOT SEAS POSSIBLE LATE SATURDAY INTO SUNDAY ACROSS THE OPEN ATLANTIC WATERS EAST OF MASSACHUSETTS*** FRIDAY NIGHT...HIGH CONFIDENCE. INCREASING NE WINDS. GUSTS UP TO 30 KT WITH SEAS BUILDING TO AROUND 5 FT ON THE OUTER WATERS. SATURDAY AND SUNDAY...MODERATE CONFIDENCE. HIGH IMPACT MARINE EVENT EXPECTED. WHILE UNCERTAINTY REMAINS ON THE EXACT TRACK AND TIMING OF A COASTAL LOW PRESSURE...HIGH CONFIDENCE GALE FORCE NORTHERLY WIND GUSTS ACROSS MOST WATERS LATE SATURDAY INTO SUNDAY. IN FACT...MODERATE RISK FOR A PERIOD OF STORM FORCE WIND GUSTS WITH 20 FOOT SEAS ACROSS THE OPEN ATLANTIC WATERS EAST OF MASSACHUSETTS. EXACT WIND SPEEDS AND WAVE HEIGHTS WILL DEPEND UPON THE EXACT TRACK AND INTENSITY OF COASTAL LOW PRESSURE. A MARINE WEATHER STATEMENT WAS ISSUED TO ADDRESS THESE CONCERNS. MONDAY...MODERATE CONFIDENCE. NORTHWEST 25-30 KT WIND GUSTS AND SEAS WILL LIKELY CONTINUE MUCH OF THE DAY WITH GOOD MIXING IN THE COLD AIR ADVECTION PATTERN. && .TIDES/COASTAL FLOODING... ASTRONOMICAL HIGH TIDES ARE NOT THAT IMPRESSIVE LATE SATURDAY INTO SUNDAY. NONETHELESS...THERE IS AT LEAST A LOW PROBABILITY FOR MINOR COASTAL FLOODING/EROSION ALONG THE EASTERN MA COAST AS WELL AS PORTIONS OF CAPE COD AND NANTUCKET. THE CONCERN IS FOR THE EARLY MORNING HIGH TIDE SUNDAY. IF WE END UP REALIZING 20 FOOT SEAS OVER THE OPEN OCEAN AND NORTHERLY WIND GUSTS OF 40 TO 50 KNOTS...THERE COULD BE SOME MINOR COASTAL FLOODING AND EROSION. SOME OF THE HOT SPOTS WOULD BE SALISBURY AND PLUM ISLAND... HULL...SCITUATE AND PERHAPS SANDWICH HARBOR AND NANTUCKET HARBOR. AGAIN...IT WILL DEPEND ON EXACT WIND SPEEDS/WAVE HEIGHTS OUT OVER THE OCEAN DURING THE EARLY MORNING SUNDAY HIGH TIDE CYCLE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...FRANK/EVT NEAR TERM...BELK/RLG/EVT SHORT TERM...EVT LONG TERM...FRANK AVIATION...FRANK/EVT MARINE...FRANK/EVT TIDES/COASTAL FLOODING...

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