Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 211806 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 205 PM EDT SUN SEP 21 2014 .SYNOPSIS... MUGGY CONDITIONS WITH A FEW HIT AND MISS SHOWERS EXPECTED THIS AFTERNOON IN MOST LOCALES...BUT A PERIOD OF RAIN IS LIKELY ACROSS THE CAPE AND NANTUCKET LATE THIS AFTERNOON/EARLY THIS EVENING. DRIER AND LESS HUMID WEATHER MONDAY AS A DRY COLD FRONT SWEEPS ACROSS THE REGION. HIGH PRESSURE DOMINATES THE WEEK AHEAD...WITH COOLER TEMPERATURES THE FIRST HALF...AND WARMER TEMPS THE LATTER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 205 PM UPDATE... MARGINAL INSTABILITY AND DEEP LOW LEVEL MOISTURE HAS ALLOWED SCATTERED SMALL SHOWERS TO AFFECT THE REGION THIS AFTERNOON. WHILE MOST OF THE TIME WAS DRY AT A GIVEN LOCATION...BRIEF SHOWERS WILL CONTINUE TO AFFECT THE REGION AT TIMES FOR THE REMAINDER OF THE AFTERNOON. MEANWHILE...SURFACE LOW OFF THE MID ATLANTIC COAST AND ITS SYNOPTIC RAIN WAS WORKING ITS WAY NORTHEAST. MOST OF THE MESOSCALE MODELS NOW AGREE THAT A PERIOD OF STEADY RAIN WILL AFFECT THE FAR SOUTHEAST NEW ENGLAND COAST LATE THIS AFTERNOON INTO PART OF THE EVENING HOURS. NOT SURE HOW MUCH IF ANY RAIN WILL MAKE IT BACK ACROSS INTERIOR SOUTHEAST MA/SOUTHERN RI...BUT IF IT DOES SHOULD BE RATHER SHORT LIVED. AFTERNOON TEMPS WILL REMAIN IN THE 70S EVEN NEAR 80 IN A FEW LOCALES. DEWPOINTS WELL INTO THE 60S WILL RESULT IN MUGGY CONDITIONS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... TONIGHT... NORTHERN STREAM TROUGH AND COLD FRONT OVER THE GREAT LAKES THIS MORNING ZIPS ACROSS THE REGION TONIGHT. MOISTURE IS LIMITED SO AREAL COVERAGE OF SHOWERS WILL BE LIMITED AND CONFINED TO THE INTERIOR. OTHERWISE MAINLY DRY TONIGHT AND MILD AS FRONTAL PASSAGE DOESN/T OCCUR UNTIL MONDAY MORNING. MONDAY... COLD FRONT MOVES ACROSS THE AREA IN THE MORNING WITH A SECONDARY FRONT PASSING IN THE AFTERNOON. MOISTURE IS LIMITED SO JUST EXPECTING SOME CLOUDS MIXING WITH THE SUNSHINE. STILL MILD AS COOLER AIR DOESN`T ARRIVE UNTIL MON NIGHT. SO EXPECTING HIGHS MON WELL INTO THE 70S INCLUDING CAPE COD AND THE ISLANDS GIVEN WESTERLY WINDS. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... HIGHLIGHTS... * DRY WEATHER FOR MOST OF THE WEEK * COOL TEMPERATURES THROUGH WED...MODERATING BY THE WEEKEND OVERVIEW AND MODEL PREFERENCES... 21.00Z LONG RANGE MODEL GUIDANCE IS SHOWING FAIRLY GOOD AGREEMENT THROUGHOUT THE LONG TERM DESPITE THE VARIANCE IN OVERALL PATTERN LATE IN THE PERIOD. THIS VARIANCE IS APPARENT IN TELECONNECTIONS...WHERE ALTHOUGH AO/NAO ARE POSITIVE...HOW STRONGLY POSITIVE IT WILL BE REMAINS IN QUESTION. IN SPITE OF THIS...FAIRLY LOCKED PATTERN ACROSS THE CONUS IS FAVORED AS CUTOFF LOW PRES/LONGWAVE TROF IN THE E GIVES WAY TO BUILDING RIDGE. THIS RIDGE IS THE RESULT OF A COMBINATION OF A SRN STREAM RIDGE CURRENTLY ACROSS THE SW/TEXAS WHICH WILL COMBINE WITH THE PERSISTENT WRN ATLANTIC RIDGE. THEREFORE...AFTER A COOL AND DIURNALLY CLOUDY START TO THE WEEK...A GRADUAL WARMING TREND IS EXPECTED THROUGH THE WEEKEND. DRY WX PREVAILS THANKS TO STRONG 1035+ HIGH PRES ASSOCIATED WITH THE BUILDING UPPER RIDGE. GIVEN THE AGREEMENT HERE...A BLEND OF GUIDANCE WILL BE USED AS A BASELINE. DETAILS... MON NIGHT INTO WED... BAFFIN ISLAND CUTOFF IS CONNECTED TO LONGWAVE TROF WITH BASE THROUGH NEW ENGLAND. THIS WILL GRADUALLY SLIDE TO THE E THROUGH THE EARLY HALF OF THE WEEK. HOWEVER...GIVEN THE PERSISTENT COOL DRAW WITH N COMPONENT TO THE FLOW...SUSPECT THIS WILL BE THE COOLEST PORTION OF THE FORECAST WITH POTENTIAL FOR DIURNAL CLOUD COVER UNDER CYCLONIC FLOW. DAYTIME HIGH TEMPS ARE LIKELY TO COOL TUE AND MORESO ON WED THANKS TO A COOLER START. H85 TEMPS REMAIN CLOSE TO +6C EACH DAY...SO NOT QUITE AS COLD AS THE LATE WEEK COOL AIRMASS OF THIS PAST WEEK. HIGHS MAINLY IN THE LOW-UPPER 60S EACH DAY. REGARDING LOWS...TUE NIGHT IS LIKELY TO BE THE COOLER OF THE TWO THANKS TO CENTER OF HIGH PRES MORE DIRECTLY OVERHEAD YIELDING WEAK FLOW. ALTHOUGH WITH RADIATIONAL COOLING SOME FROST IS POSSIBLE EITHER NIGHT IN THE COOLER VALLEYS PARTICULARLY IN NW MA OR SW NH. THU INTO THE WEEKEND... HIGH PRES WILL BE SLOWLY CRESTING OVER THE REGION WITH TIME. LOW- MID LVL HEIGHTS CONTINUE TO RISE SUGGESTING INCREASING TEMPS THROUGH THE COLUMN...THEREFORE...MODERATE TEMPS ARE EXPECTED EACH DAY AS WELL. H85 TEMPS START ABOUT +9C THU...THEN MAY REACH BETWEEN +12C AND +14C BY SUN. WITH MODERATION EACH DAY SUSPECT THAT HIGHS WILL START NEAR NORMAL...INCREASING TO ABOVE NORMAL BY THE WEEKEND...AT WHICH POINT HIGHS IN THE UPPER 70S FOR THE WEEKEND. FOR WHAT IT/S WORTH...EVEN THOUGH THE BLOCKING PATTERN SUGGESTS THE DRY HIGH PRES AND ASSOCIATED SUBSIDENCE DOMINATES...THERE IS AN INVERTED TROF IN THE MID ATLANTIC WITH HIGHER MOISTURE WHICH MAY NEED TO BE WATCHED. WILL MAINTAIN A DRY FORECAST FOR NOW AS A DRY PATTERN SUCH AS THIS GENERALLY SUGGESTS POSITIVE FEEDBACK...MAINTAINING ITSELF. HOWEVER...WITH THE VARIANCE EVIDENT IN THE OVERALL FLOW PATTERN ALOFT LATE IN THE WEEK...MAY NEED TO MONITOR THIS INVERTED TROF AND SUBTROPICAL MOISTURE WHICH COULD YIELD A CHANGE IN THE FORECAST. INDIVIDUAL ENSEMBLE MEMBERS FROM BOTH THE GEFS AND ECENS DO BRING THIS TROF CLOSER TO NEW ENGLAND THAN DO OTHER MEMBERS AND THE OPERATIONAL MODELS. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY NIGHT/... REST OF THIS AFTERNOON...MODERATE CONFIDENCE. MAINLY MVFR CIGS WERE DOMINATING AT MID AFTERNOON...BUT SOME IFR CONDITIONS WERE DEVELOPING ACROSS THE CAPE AND NANTUCKET. MAY SEE CONDITIONS LOWER TO IFR IN SOME LOCALES NEAR THE SOUTHEAST NEW ENGLAND COAST THROUGH EARLY EVENING. REST OF THE REGION SHOULD MAINLY BE MVFR. TONIGHT...LOW TO MODERATE CONFIDENCE. GUIDANCE SEEMS A BIT TOO PESSIMISTIC ON CEILINGS/VISIBILITIES GIVEN WINDS SHIFTING TO MORE OF A WESTERLY DIRECTION LATER THIS EVENING...ALBEIT LIGHT. PATCHES OF IFR CONDITIONS STILL LIKELY THOUGH...ESPECIALLY IF ANY PATCHY FOG CAN DEVELOP. WIDESPREAD IFR CONDITIONS MOST LIKELY NEAR THE FAR SOUTHEAST NEW ENGLAND COAST. AGAIN...FORECAST CONFIDENCE IS LOW TO MODERATE SO LATER SHIFTS WILL HAVE TO MONITOR TRENDS CLOSELY. MONDAY AND MONDAY NIGHT...HIGH CONFIDENCE IN VFR CONDITIONS. JUST A LOW RISK FOR BRIEF MVFR CIGS ACROSS THE INTERIOR ON MONDAY AS A DECK OF STRATO-CUMULUS CLOUDS MOVES INTO THE REGION. OTHERWISE...GUSTY WEST TO NORTHWEST WINDS OF 20 TO 25 KNOTS EXPECTED DURING THE DAY MONDAY. KBOS TERMINAL...MODERATE CONFIDENCE TONIGHT WITH HIGH CONFIDENCE ON MONDAY. KBDL TERMINAL...MODERATE CONFIDENCE TONIGHT WITH HIGH CONFIDENCE ON MONDAY. OUTLOOK...TUESDAY THROUGH THURSDAY... HIGH CONFIDENCE. VFR DOMINATES THROUGH THE PERIOD. A FEW POCKETS OF EARLY MORNING FOG AT TYPICALLY PRONE TERMINALS EACH NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... TODAY... MODEST S-SE WINDS WITH HEAVY SHOWERS ACROSS THE WESTERN WATERS. VSBY REDUCED IN HEAVY RAIN AND PATCHY FOG. TONIGHT... SHOWERS DIMINISH. SEAS BUILD ACROSS THE OCEAN WATERS THUS SCA IN EFFECT. SSW WINDS SHIFT TO WEST TOWARD SUNRISE. MONDAY... WEST WINDS YIELD GOOD VSBY AND DRY WEATHER. HOWEVER SEAS REMAIN ROUGH FROM LEFTOVER SOUTH SWELL COMBINED WITH DEVELOPING WEST WIND WAVES. OUTLOOK...MONDAY NIGHT THROUGH THURSDAY... HIGH CONFIDENCE... 5-8 FT SEAS AND WINDS BOTH DIMINISH MON NIGHT...SUCH THAT SMALL CRAFT ADVISORIES ARE LIKELY TO END. ALTHOUGH THE SWELL MAY LINGER A BIT INTO TUE...EVEN THESE SHOULD DROP BELOW SMALL CRAFT ADVISORY THRESHOLDS EARLY. OTHERWISE...MAINLY QUIET BOATING WEATHER FOR THE REMAINDER OF THE PERIOD UNDER HIGH PRES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EDT MONDAY FOR ANZ235-237-250-254>256. && $$ SYNOPSIS...FRANK/NOCERA/DOODY NEAR TERM...FRANK SHORT TERM...NOCERA LONG TERM...DOODY AVIATION...FRANK/DOODY MARINE...NOCERA/DOODY

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