Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 211313 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 913 AM EDT SUN SEP 21 2014 .SYNOPSIS... SHOWERS WITH LOCALLY HEAVY RAIN THIS MORNING MAINLY OVER CONNECTICUT...WESTERN-CENTRAL MASSACHUSETTS INTO SOUTHERN NEW HAMPSHIRE WILL BECOME LESS NUMEROUS THIS AFTERNOON FROM WEST TO EAST. WARM AND MUGGY CONDITIONS TODAY WILL BE REPLACED BY 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/...
-- Changed Discussion --
910 AM UPDATE... WHILE MOST OF THE REGION WAS DRY AT MID MORNING...A NARROW BAND OF SCATTERED SHOWERS CONTINUED TO AFFECT A SMALL PORTION OF NORTHERN CT AND INTO CENTRAL MA. THERE STILL WAS SOME BRIEF LOCALLY HEAVY RAIN...BUT NOT AS HEAVY WHAT WE SAW EARLIER THIS MORNING AS THE LOW LEVEL JET HAS WEAKENED A TAD. OVERALL...SCATTERED HIT AND MISS SHOWERS WILL CONTINUE INTO THE AFTERNOON. WE MAY SEE THEM EXPAND A BIT INTO EASTERN MA/RHODE ISLAND BY AFTERNOON AS SURFACE INSTABILITY INCREASES...DESPITE WEAKENING WIND FIELDS. NOT LOOKING AT A WASHOUT THOUGH AS MUCH OF THE TIME WILL FEATURE DRY WEATHER IN A SPECIFIC LOCATION. THE OTHER MAIN FEATURE WE ARE WATCHING IS THE SYNOPTIC RAIN SHIELD ASSOCIATED WITH THE SURFACE LOW OFF THE MID ATLANTIC COAST. WHILE LACK OF BAROCLINICITY WILL LIKELY KEEP MOST OF THE ACTIVITY OFFSHORE...APPEARS IT MAY CLIP THE FAR SOUTHEAST NEW ENGLAND COAST FOR A FEW HOURS LATER THIS AFTERNOON INTO EARLY THIS EVENING. THIS IS MAINLY FOR THE CAPE AND NANTUCKET...BUT PERHAPS GETTING A BIT FURTHER NORTHWEST THAN THAT FOR A FEW HOURS. HIGH TEMPS THIS AFTERNOON ARE TRICKY. LOTS OF CLOUDS AND SCATTERED SHOWERS ACROSS THE INTERIOR SHOULD KEEP HIGHS MAINLY IN THE MID TO UPPER 70S. STILL RATHER HUMID THOUGH GIVEN DEWPOINTS IN THE 60S. ACROSS PORTIONS OF INTERIOR SOUTH EASTERN MA/RI...WILL LIKELY SEE SOME 80 DEGREE HIGHS WHERE SUN WAS OUT THIS MORNING. CLOUDS SHOULD INCREASE IN THIS REGION THIS AFTERNOON AS LOW PRESSURE OFF THE MID ATLANTIC COAST LIFTS NORTHEASTWARD. CERTAINLY A DRAMATIC CHANGE BACK TO SUMMER WEATHER AFTER THE VERY CHILLY START EARLY YESTERDAY MORNING!
-- End Changed Discussion --
&& .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 /13Z SUNDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY/... 12Z UPDATE...MODERATE CONFIDENCE. MIX OF MVFR/IFR IN A LINE FROM CT THROUGH CENTRAL AND WESTERN MA INTO SRN NH. THIS WILL LINGER THROUGH THE MORNING UNTIL LEFTOVER SHOWERS COME TO AN END. OTHERWISE...MAINLY VFR ALTHOUGH SOME LOW CLOUDS MAY MOVE INTO SOUTHEAST MA LATE IN THE DAY. TONIGHT...MAINLY VFR EXCEPT MVFR/IFR CAPE COD AND THE ISLANDS EARLY HALF OF THE NIGHT. CHANCE OF A BROKEN LINE OF SHOWERS AROUND 06Z ESPECIALLY WESTERN- CENTRAL MA INTO NH. MONDAY...VFR. MODEST W WIND. DRY RUNWAYS. KBOS TERMINAL..MODERATE CONFIDENCE IN TAF ON TIMING BUT LOWER CONFIDENCE ON AREAL COVERAGE OF SHOWERS. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. OUTLOOK...MONDAY NIGHT 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...NOCERA/DOODY NEAR TERM...FRANK SHORT TERM...NOCERA LONG TERM...DOODY AVIATION...NOCERA/DOODY MARINE...NOCERA/DOODY

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.