Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 050228 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1020 PM EDT MON MAY 4 2015 .SYNOPSIS... MILD WEATHER PREVAILS THIS EVENING AND OVERNIGHT AHEAD OF AN APPROACHING COLD FRONT. THIS BOUNDARY MAY TRIGGER ISOLATED TO WIDELY SCATTERED SHOWERS TUESDAY. HIGH PRESSURE BUILDS IN BEHIND THIS FRONT WED...PROVIDING MILD TEMPERATURES BUT LOWER HUMIDITY THAN TUESDAY. WARMER WEATHER FOLLOWS THU AND FRI AS THE HIGH SLIPS SOUTH AND THEN EAST OF NEW ENGLAND. A COLD FRONT LATE THIS WEEKEND INTO EARLY NEXT WEEK MAY YIELD SCATTERED SHOWERS. OTHERWISE DRY... WARM AND SLIGHTLY MORE HUMID WEATHER PREVAILS THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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1027 PM UPDATE... MILD SOUTHWEST FLOW CONTINUES AHEAD OF AN APPROACHING COLD FRONT. WHILE WINDS HAVE DIMINISHED SOME WITH THE LOSS OF DAYTIME HEATING...STILL ENOUGH WIND OFF THE DECK TO KEEP THEM FROM DECOUPLING. THIS WAS ALLOWING LATE EVENING TEMPS TO STILL BE IN THE 60S TO NEAR 70...DESPITE RELATIVELY DRY AIR IN PLACE. DRY WEATHER CONTINUES FOR MOST OF THE NIGHT...BUT MID/HIGH LEVEL CLOUDINESS WILL INCREASE AHEAD OF THE COLD FRONT. AS THE COLD FRONT APPROACHES TOWARD DAYBREAK A FEW SPOT SHOWERS MAY DEVELOP BUT NOTHING SIGNIFICANT/WIDESPREAD EXPECTED. ITS SO DRY IN THE LOW LEVELS OF THE ATMOSPHERE AND INSTABILITY IS QUITE LIMITED. THEREFORE...WHILE A FEW SPOT SHOWERS POSSIBLE TOWARD DAYBREAK DRY WEATHER WILL DOMINATE. REMOVED MENTION OF THUNDER AS INSTABILITY APPEARS TOO LIMITED. LOW TEMPS BY DAYBREAK SHOULD ONLY DROP INTO THE UPPER 50S TO NEAR 60 BY DAYBREAK FOR MOST LOCATIONS...BUT IT WILL BE A FEW DEGREES COOLER ACROSS THE SOUTH COAST/CAPE/ISLANDS.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... A WEAKENING COLD FRONT WILL PROVIDE A FOCUS FOR ISOLATED TO SCATTERED SHOWERS ACROSS SOUTHERN NEW ENGLAND. INSTABILITY IS NOT GREAT...BUT CANNOT COMPLETELY RULE OUT THE POSSIBILITY OF AN ISOLATED THUNDERSTORM OR TWO. THE MOST LIKELY SCENARIO IS FOR SCATTERED SHOWERS...ESPECIALLY DURING THE MORNING HOURS. THE FRONT CONTINUES TO WEAKEN DURING THE AFTERNOON...WITH WEAK RIDGING ARRIVING DURING TUESDAY EVENING AND OVERNIGHT. THIS SHOULD MEAN A SLOW DRYING TREND TUESDAY NIGHT. TEMPERATURES WILL STILL BE SLIGHTLY ABOVE NORMAL TUESDAY AND TUESDAY NIGHT. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... 348 PM UPDATE... HIGHLIGHTS... * SPRING TO SUMMER-LIKE TEMPS MUCH OF THE PERIOD * MAINLY DRY WEATHER WED THRU SAT WITH INCREASING RISK OF SHOWERS SUN/MON SYNOPTIC OVERVIEW AND MODEL/GUIDANCE EVALUATION... 00Z ECENS/EPS AND 12Z GEFS ENSEMBLES IN GOOD AGREEMENT ON THE LARGE SCALE FLOW THIS PERIOD WHICH FEATURES AN ANOMALOUS CLOSED LOW EVOLVING OVER THE NORTHWEST ATLANTIC OF ABOUT -3 STD DEVIATIONS FROM CLIMO...ALONG WITH A RIDGE CENTERED OVER THE GREAT LAKES AND OHIO VALLEY. THIS PLACES NEW ENGLAND IN A DRY NORTHWEST FLOW REGIME WED THRU FRI. BY THE WEEKEND THE UPPER AIR PATTERN BECOMES SOMEWHAT PROGRESSIVE WITH THE CLOSED LOW MOVING INTO THE CENTRAL ATLANTIC ALLOWING GREAT LAKES RIDGE/HEIGHT ANOMALY TO ADVECT EASTWARD INTO NEW ENGLAND...CONTINUING THE DRY WEATHER INTO AT LEAST THE FIRST HALF OF THE WEEKEND. THEN BY LATE IN THE WEEKEND AND ESPECIALLY EARLY NEXT WEEK THE QUESTION BECOMES HOW QUICKLY DOES THE RIDGE ERODE AS UPSTREAM TROUGH APPROACHES. IN ADDITION...RIDGE BECOMES SOMEWHAT OF A DIRTY RIDGE WITH MOISTURE FROM REMNANT CLOSED LOW OVER THE SOUTHEAST STATES ADVECTING NORTHWARD UP THE EASTERN SEABOARD. AS EXPECTED AT THIS TIME RANGE THE DETERMINISTIC RUNS OF THE 12Z ECMWF AND 12Z GFS HANDLE THIS DIFFERENTLY ALONG WITH ENSEMBLES. THUS FORECAST CONFIDENCE BECOMES LOW ON SHOWER POTENTIAL LATER THIS WEEKEND INTO EARLY NEXT WEEK. TEMPERATURES... BRIEF COOL DOWN OR BETTER LABELED AS NOT AS WARM WED /LOW TO MID 70S/ IN THE POST FRONTAL AIRMASS ALONG WITH LOWER DEW PTS /30S/. HOWEVER AS SURFACE HIGH SLIPS SOUTH OF NEW ENGLAND THU...SURFACE WINDS BECOME WSW AND THIS WILL SUPPORT TEMPS WARMING TO 75 TO 80 AND POTENTIALLY CLIMBING INTO U70S AND L80S BY FRI. WARM WEATHER CONTINUES SAT WITH HIGHS IN THE L80S AWAY FROM THE SOUTH COAST. IN ADDITION WITH SSW SURFACE WINDS DEW PTS WILL CLIMB INTO THE 50S. STILL COMFORTABLE BUT THIS WILL RESULT IN NIGHTLY TEMPS NOT AS COOL ALONG WITH PATCHY FOG. SUNDAY...TRICKY AS POTENTIAL BACKDOOR FRONT IMPACTS EASTERN MA AND POSSIBLY RI. NOT AS WARM EARLY NEXT WEEK GIVEN LIKELY CLOUD COVER...SOUTHERLY FLOW AND RISK OF SHOWERS. HOWEVER TEMPS WILL STILL AVERAGE WARMER THAN NORMAL. PRECIPITATION... AS MENTIONED ABOVE DRY PATTERN PREVAILS WED THRU FRI AND PROBABLY INTO SAT. RISK OF SHOWERS INCREASES SUNDAY AS UPSTREAM TROUGH APPROACHES ALONG WITH REMNANT MOISTURE OFFSHORE FROM CLOSED LOW OVER THE SOUTHEAST STATES LATER THIS WEEK. HOWEVER GREATEST RISK OF SHOWERS APPEARS TO BE EARLY NEXT WEEK AS UPSTREAM TROUGH GETS CLOSER TO THE REGION AND BEGINS TO INTERACT WITH DEEPER MOISTURE ALONG AND OFF THE EASTERN SEABOARD. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TUE NIGHT. 7 PM UPDATE... ONLY CHANGE IS TO ADD LLWS TO TAF SITES IN EASTERN MA AND RI FOR LOW LEVEL SOUTHWEST JET OF UP TO 50 KT PEAKING AROUND 06Z TONIGHT. EARLIER DISCUSSION BELOW. ================================================================= SW WINDS MAY BRING SOME 20-25KT GUSTS THROUGH EARLY EVENING...OTHERWISE VFR THROUGH TONIGHT. VFR CIGS TUE AS COLD FRONT DROPS THROUGH SOUTHERN NEW ENGLAND...WITH SCATTERED SHOWERS POSSIBLE. MAY SEE SOME MVFR CIGS NEAR S COAST TUE AFTERNOON. VFR TUE NIGHT. KBOS TAF...HIGH CONFIDENCE IN TAF. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...WEDNESDAY THROUGH SATURDAY... 348 PM UPDATE... HIGH CONFIDENCE FOR VFR AND DRY WEATHER. LOW RISK FOR PATCHY FOG EACH NIGHT BETWEEN MIDNIGHT AND SUNRISE WITH LOCAL IFR CIGS/VSBYS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/... TONIGHT INTO TOMORROW...MODERATE CONFIDENCE. THE SW FLOW WILL SLOWLY GIVE WAY TO W FLOW AS A COLD FRONT CROSS THE WATERS DURING THE TUE EVENING HOURS. WITH THE PERSISTENT SW FLOW TODAY...SOME CONCERN WIND-DRIVEN SEAS COULD APPROACH 5 FT ON THE OCEAN WATERS. IT IS MARGINAL...BUT DID HAVE ENOUGH CONFIDENCE TO ISSUE A SMALL CRAFT ADVISORY ACROSS THE OUTER COASTAL WATERS. THE MAIN RISK WILL BE ROUGH SEAS...BUT COULD SEE A FEW GUSTS TO 25 KT AS WELL AHEAD OF A COLD FRONT. CONDITIONS IMPROVE TUESDAY AFTERNOON. SOME SHOWERS...WITH POSSIBLY EVEN A THUNDERSHOWER. TUESDAY NIGHT...WINDS AND SEAS CONTINUE TO DIMINISH. OUTLOOK...WEDNESDAY THROUGH SATURDAY... 348 PM UPDATE... WEDNESDAY...HIGH PRES OVER THE WATERS WITH TRANQUIL/DRY WEATHER AND GOOD VSBY. HIGH FORECAST CONFIDENCE. THURSDAY...HIGH SLIPS SOUTH OF NEW ENGLAND WITH WINDS BECOMING SSW. TRANQUIL/DRY WEATHER WITH GOOD VSBY CONTINUES. FRIDAY...HIGH PRES MOVES EAST OF NEW ENGLAND. DRY/TRANQUIL WEATHER CONTINUES. && .FIRE WEATHER... OVERNIGHT...FIRE WEATHER HEADLINES WERE CANCELLED AS WIND GUSTS HAVE DIMINISHED WITH LOSS OF DAYTIME HEATING. WINDS WILL NOT BE NEARLY AS STRONG ON TUESDAY SO NO FIRE WEATHER HEADLINES ANTICIPATED. THURSDAY...LOW RISK OF ELEVATED FIRE WEATHER CONCERNS WITH MIN RH VALUES DIPPING TO 25 TO 30 PERCENT ALONG WITH WSW WIND GUSTS UP TO 20 MPH. SUSTAINED WINDS WILL BE LESS 10-15 MPH BUT AGAIN GUSTS UP TO 20 MPH AND PERHAPS 25 MPH ARE POSSIBLE. WHILE ISOLATED OR WIDELY SCATTERED SHOWERS ARE POSSIBLE TUE MOST OF THE REGION WILL BE DRY WITH ANY RAINFALL LIKELY LESS THAN 0.25 INCHES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT TUESDAY FOR ANZ250. SMALL CRAFT ADVISORY UNTIL 3 PM EDT TUESDAY FOR ANZ254. SMALL CRAFT ADVISORY UNTIL 3 PM EDT TUESDAY FOR ANZ255-256. && $$ SYNOPSIS...NOCERA NEAR TERM...FRANK SHORT TERM...BELK LONG TERM...NOCERA AVIATION...NOCERA/JWD MARINE...BELK/NOCERA FIRE WEATHER...STAFF

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