Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 241959 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 359 PM EDT THU APR 24 2014 .SYNOPSIS... WINDS DIMINISH TONIGHT AS HIGH PRESSURE BUILDS INTO NEW ENGLAND FROM THE WEST...PROVIDING CHILLY TEMPERATURES BUT THEN REBOUNDING NICELY FRIDAY WITH MILD CONDITIONS AND LIGHT WINDS. LOW PRESSURE THEN BRINGS RAIN FRIDAY NIGHT INTO SATURDAY...FOLLOWED BY A DRYING TREND SUNDAY AND CONTINUING INTO EARLY NEXT WEEK ALONG WITH SEASONABLE TEMPERATURES AS HIGH PRESSURE RETURNS TO THE AREA. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 340 PM UPDATE... POWERFUL LATE SEASON OCCLUDED LOW SOUTH OF NOVA SCOTIA WILL CONTINUE TO GENERATE WINDY CONDITIONS ACROSS SOUTHERN NEW ENGLAND THROUGH SUNSET AND THEN BEGIN TO DIMINISH WITH NIGHTFALL AND ESPECIALLY AFTER MIDNIGHT. THE COMBINATION OF DIMINISHING WINDS/CLEAR SKIES AND A VERY DRY AIRMASS WITH DEW PTS IN THE TEENS AND 20S WILL RESULT IN A CHILLY NIGHT ACROSS SOUTHERN NEW ENGLAND. A BLEND OF ALL DATA SOURCES YIELDS MINS TONIGHT IN THE 30S REGIONWIDE...EXCEPT UPPER 20S IN THE DEEPER INTERIOR VALLEYS SUCH AS THE CT RVR VLY. THE OTHER EXCEPTION WILL BE IN THE CITY OF BOSTON...CAPE COD AND THE ISLANDS WHERE WINDS WILL NOT COMPLETELY DIMINISH AND KEEP MIN TEMPS AROUND 40. AS FOR FROST/FREEZE HEADLINES...THE GROWING SEASON HAS ONLY BEGUN ALONG THE SOUTH COAST. HERE ACROSS COASTAL RI AND SOUTH COASTAL MA TEMPS WILL DIP INTO THE M30S FOR A TIME FROM ABOUT 3 AM TO 7 AM. THIS WILL BE SUFFICIENT FOR WIDESPREAD FROST. GIVEN GROWING SEASON IS ALREADY IN PROGRESS HERE WILL ISSUE A FROST ADVISORY. DID NOT INCLUDE COMMUNITIES NEAR NARRAGANSETT BAY AS WINDS WILL LIKELY NOT DECOUPLE HERE KEEPING TEMPS IN THE U30S AND L40S. THUS LOWER RISK OF WIDESPREAD FROST. ELSEWHERE/INLAND TEMPS WILL BE COLDER HOWEVER NO HEADLINES GIVEN GROWING SEASON FOR MOST LOCATIONS DOESN/T START UNTIL SOMETIME IN MAY. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FRIDAY... REAL NICE DAY WITH LIGHT WINDS AS HIGH PRES CREST OVER THE REGION. DEEP LAYER SUBSIDENCE WILL PROVIDE LOTS OF SUNSHINE WITH STRONG APRIL SUN ANGLE WARMING AIRMASS INTO THE LOW AND MID 60S INLAND. COOLER ALONG THE COAST WITH DEVELOPING SEABREEZES BUT OVERALL A NICE DAY BY LATE APR STANDARDS AND CONSIDERING WHAT THE WEEKEND AND EXTENDED FORECAST OFFERS. FRIDAY NIGHT... ROBUST TROUGH OVER THE SOUTHERN PLAINS THIS AFTERNOON CONTINUES MOVING EASTWARD AND ARRIVES HERE FRI NIGHT. MODELS IN VERY GOOD AGREEMENT ON THIS SYSTEM...WITH PARENT LOW ENTERING WESTERN NY EARLY SAT...WHILE SECONDARY LOW SPINS UP NEAR LONG ISLAND NY. RAIN OVERSPREADS WESTERN PORTIONS OF CT AND MA 8 PM TO 2 AM...THEN ACROSS RI AND EASTERN MA 2 AM TO 8 AM. A PERIOD OF HEAVY RAIN POSSIBLE GIVEN MODEST ATLANTIC INFLOW AND JET DYNAMICS TOWARD 12Z SAT. && .LONG TERM /SATURDAY THROUGH THURSDAY/...
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HIGHLIGHTS... * UNSETTLED WEATHER IS EXPECTED ON SATURDAY...LOW CONF ON WASHOUT * UNSEASONABLE TEMPS AND UNSETTLED WEATHER MID NEXT WEEK MODELS AND CONFIDENCE... 12Z SYNOPTIC PATTERN IS IN GOOD AGREEMENT. HOWEVER THE EC IS MORE PROGRESSIVE ON PUSHING OUT THE BLOCKING PATTERN THEN THE GFS. OVERALL CONTINUED FOCUSING THE FORECAST BASE ON THE ENSEMBLES AS THE DETERMINISTIC GUIDANCE IS STILL SOMEWHAT SPREAD OUT. HOWEVER WITH BOTH THE NAO AND AO FORECASTED TO BE NEGATIVE AND WITH THE PNA EXPECTED TO BE MORE POSITIVE...THERE IS INCREASING CONFIDENCE OF A BLOCKING/TROUGH OVER THE NORTHEAST ALLOWING FOR MORE UNSETTLED WEATHER. QUICK MOVING SHORTWAVE OVER THE GREAT LAKES WILL MOVE INTO THE REGION PUSHING A DOUBLE BARREL LOW THROUGH NEW ENGLAND BY SATURDAY. THESE LOW PRESSURE SYSTEMS WILL EVOLVE INTO A CUT OFF UPPER LEVEL LOW WHICH CONTINUE TO INFLUENCE THE REGION BY WOBBLING OVER THE MARITIMES INTO MONDAY. HOWEVER A CLOSED TROUGH/LOW OVER THE ROCKIES ON MONDAY WILL EVENTUALLY BE FORCED EASTWARD ACROSS THE EASTERN US BY WED IN A DEVELOPING REX BLOCK SETUP AS WARMING RIDGES BUILD STRONGLY OVER THE WRN US. DETAILS... SATURDAY... A DOUBLE BARROW LOW WILL MOVE OVER SOUTHERN NEW ENGLAND ON SATURDAY. AS THE FIRST LOW MOVES THROUGH THE DETERMINISTIC MODELS AGREE THAT HEAVY PRECIP WILL OCCUR SAT MORNING INTO THE EARLY AFTERNOON HOURS THANKS TO GOOD ATLANTIC MOISTURE PLUME AND DESCENT JET DYNAMICS. BELIEVE THAT THE HEAVIEST PRECIP WILL OCCUR ON THE NW PORTION OF THE LOW. AS THE FIRST LOW MOVES THROUGH AND THE SECOND SHORTWAVE MOVES INTO THE REGION...ANOTHER SHOT OF PRECIP...MORE SHOWERY WEATHER... WILL MOVE THROUGH DURING THE EVENING HOURS. SO THERE IS A LOW PROBABILITY THAT THERE MAY BE A BREAK IN THE PRECIP ON SATURDAY. DURING THE EVENING HOURS THE REGION LOSES THE GOOD MOISTURE PLUME HOWEVER...SOME OF THE MOISTURE MAY MOVE ON THE BACKSIDE OF THE LOW. YET THE JET DYNAMICS ARE NOT IN FAVOR FOR HEAVY RAIN...SO HAVE MODERATE CONFIDENCE IN MORE SHOWERY WEATHER SATURDAY EVENING INTO THE OVERNIGHT HOURS. GUIDANCE CONTINUES TO INDICATE SOME ELEVATED INSTABILITY MOVING THROUGH ON SATURDAY SO HAVE INSERTED ISO THUNDER FOR NOW. HOWEVER FOCUSED MORE ON THE SOUTHERN HALF OF THE REGION WHERE THE BETTER PARAMETERS ARE LOCATED. AS THE SURFACE LOW APPROACHES...EASTERLY WINDS WILL DEVELOP ON SATURDAY RESULTING IN A MUCH COOLER COAST THEN ORIGINALLY THOUGH. HAVE DROP TEMPS DOWN INTO THE UPPER 40S TO LOW 50S. HOWEVER ACROSS THE CT VALLEY...IF CLOUDS BREAK OUT THEN TEMPS COULD SOAR INTO THE MID 50S THANKS TO THE HIGH APRIL SUNSHINE. ANY ADJUSTMENTS IN THE TRACK OF THE LOW COULD CAUSE CHANGES IN THE TEMPS. SUNDAY INTO MONDAY NORTHERLY FLOW WILL CONTINUE INTO SUNDAY KEEPING TEMPERATURES DOWN IN THE LOW TO MID 50S ACROSS THE REGION. HOWEVER WITH THE STRONG LOW PRESSURE SYSTEM JUST OFFSHORE APPEARS THAT THERE COULD BE SOME LINGERING SHOWERS. NORTHWESTERLY FLOW WILL CONTINUE ON MONDAY AND TUESDAY. CONDITIONS LOOK TO BE BREEZY ON MONDAY WITH THE DEPARTING LOW MOVING OFFSHORE AND WEAK HIGH PRESSURE TRYING TO MOVE INTO THE REGION...INCREASING THE PRESSURE GRADIENT. TEMPERATURES WILL BE CLOSE TO AVERAGE. TUESDAY INTO THURSDAY... BLOCKING PATTERN APPEARS TO SET-UP OVER THE REGION DURING THE MID TO PERHAPS THE END OF NEXT WEEK. AS AN UPPER LEVEL LOW WOBBLES ACROSS THE MIDWEST...APPEARS THAT A TROUGH WILL SET UP OVER THE NORTHEAST. THIS LOW WILL ALLOW FOR EASTERLY WINDS ACROSS THE REGION AS WELL AS CLOUDY SKIES. THEREFORE HAVE INCREASING CONFIDENCE THAT TEMPERATURES WILL BE WELL BELOW AVERAGE FOR THIS TIME OF YEAR AND EXPECT SEVERAL ROUNDS OF PRECIP. HOWEVER HAVE A LOW CONFIDENCE ON WHEN EXACTLY EACH ROUND OF PRECIP WILL OCCUR AND WHERE THE HEAVIEST WILL RESIDE. FOR NOW...HAVE INCREASING CONFIDENCE THAT COOL TEMPS AND UNSETTLED WEATHER WILL OCCUR.
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&& .AVIATION /20Z THURSDAY THROUGH TUESDAY/...
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LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH 12Z SATURDAY/...HIGH CONFIDENCE 4 PM UPDATE... THROUGH 00Z...GUSTY NW WINDS 30-40 KT CONTINUE THEN BEGINNING TO DIMINISH AROUND SUNSET. VFR AS WELL. AFTER 00Z...VFR WITH A DIMINISHING WIND. FRIDAY...VFR WITH LIGHT WINDS...SEABREEZES ALONG THE COAST. FRIDAY NIGHT...VFR TO START THEN QUICKLY LOWERING TO MVFR WITH RAIN OVERSPREADING WESTERN CT/MA 00Z-06Z THEN INTO RI AND EASTERN MA 06Z-12Z. LOW RISK OF IFR TOWARD 12Z SAT. EAST-SOUTHEAST WINDS MAY INCREASING UP TO 25 KT TOWARD 12Z SAT ACROSS RI AND EASTERN MA. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...SATURDAY THROUGH TUESDAY... SATURDAY...MODERATE CONFIDENCE. MAINLY VFR. BRIEF PERIODS OF MVFR/IFR CONDITIONS IN RAIN SHOWERS/FOG. SUNDAY INTO TUESDAY...LOW CONFIDENCE. VFR. SOME SHOWERY WX POSSIBLE ON THE EAST COAST ON SUNDAY.
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&& .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. TONIGHT... NW GALES UNTIL 8 PM OR SO FOLLOWED BY DIMINISHING WINDS OVERNIGHT. STRONGEST WINDS NEAR SHORE. FRI...HIGH PRES CREST OVER THE REGION YIELDING LIGHT WINDS WITH SEABREEZES NEAR SHORE. DRY WEATHER AND GOOD VSBY. FRI NIGHT...RAIN OVERSPREADS THE WATERS FROM WEST TO EAST. RAIN HEAVY AT TIMES TOWARD SUNRISE SAT. LOW RISK OF THUNDER SOUTH WATERS. AS LOW DEVELOPS SOUTH OF LONG ISLAND EAST TO SOUTHEAST WINDS MAY INCREASE TO 20-30 KT TOWARD SUNRISE SAT WITH STRONGEST WINDS SOUTH OF NANTUCKET AND MARTHAS VINEYARD. OUTLOOK...SATURDAY INTO TUESDAY... SATURDAY...LOW TO MODERATE CONFIDENCE. S WINDS AND SEAS INCREASE AS A LOW PRESSURE SYSTEM APPROACHES THE WATERS. VISIBILITIES MAY BE REDUCED AT TIMES IN RAIN SHOWERS. SMALL CRAFT ADVISORIES MAY BE NECESSARY. WINDS SHIFT TO THE NW AS THE COLD FRONT CROSSES THE WATERS. SUNDAY...MODERATE CONFIDENCE. N/NW WINDS WILL INCREASE AS SURFACE PRESSURE GRADIENT TIGHTENS OVER THE WATERS. SEAS WILL BUILD IN RESPONSE. SMALL CRAFT ADVISORIES MAY BE NEEDED. MONDAY INTO TUESDAY...UPPER LEVEL LOW OVER THE MARITIMES WILL CONTINUE TO KEEP PRESSURE GRADIENT TIGHT KEEPING THE WINDS UP AS WELL AS SEAS. SMALL CRAFT ADVISORIES MAY BE NEEDED THROUGH THE PERIOD.
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&& .FIRE WEATHER... ELEVATED FIRE WEATHER CONDITIONS CONTINUE UNTIL SUNSET AND THEN DIMINISH WITH NIGHTFALL. UNTIL THEN EXPECT NW WINDS 20-30 MPH WITH GUSTS UP TO 45 MPH AND RH VALUES 15-25 PERCENT. RECENT RAINFALL IN CENTRAL AND EASTERN NEW ENG WILL PRECLUDE RED FLAG CONDITIONS IN THESE AREAS. HOWEVER...LESS RAINFALL OCCURRED IN THE CT VALLEY THUS RED FLAG WARNING CONTINUES FOR CT. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR CTZ002>004. MA...WIND ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MAZ004>007- 012>021-026. FROST ADVISORY FROM 3 AM TO 7 AM EDT FRIDAY FOR MAZ020-021. NH...WIND ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ011-012-015. RI...WIND ADVISORY UNTIL 7 PM EDT THIS EVENING FOR RIZ001>007. FROST ADVISORY FROM 3 AM TO 7 AM EDT FRIDAY FOR RIZ006. MARINE...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR ANZ230>237-250- 251-254>256.
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&& $$ SYNOPSIS...NOCERA/DUNTEN NEAR TERM...NOCERA SHORT TERM...NOCERA LONG TERM...DUNTEN AVIATION...NOCERA/DUNTEN MARINE...NOCERA/DUNTEN FIRE WEATHER...STAFF

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