Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 122231 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 630 PM EDT FRI SEP 12 2014 .SYNOPSIS... HIGH PRESSURE BUILDS INTO SOUTHEAST CANADA AND MAINE BRINGING A COOL NIGHT TO SOUTHERN NEW ENGLAND. A QUICK MOVING WEATHER SYSTEM THEN BRINGS SCATTERED SHOWERS LATE SATURDAY AFTERNOON AND EARLY EVENING. HIGH PRESSURE BRINGS DRY WEATHER WITH SLIGHTLY BELOW NORMAL TEMPERATURES SUNDAY INTO MONDAY. THE NEXT COLD FRONT WILL LIKELY BRING A PERIOD OF SHOWERS LATE MONDAY NIGHT INTO TUESDAY. MAINLY DRY WEATHER EXPECTED NEXT WEDNESDAY THROUGH FRIDAY WITH SLIGHTLY BELOW NORMAL TEMPERATURES CONTINUING. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 630 PM UPDATE... STRATO-CUMULUS CLOUDS HAVE DISSIPATED EARLY THIS EVENING ACROSS THE CAPE AND ISLANDS. OTHERWISE...MAINLY CLEAR SKIES WERE IN PLACE EARLY THIS EVENING OTHER THAN A TOUCH OF HIGH CLOUDINESS. IDEAL SEP WEATHER ACROSS THE REGION THROUGH THE EVENING WITH MAINLY CLEAR SKIES...COMFORTABLE TEMPS AND LIGHT WINDS. AFTER SUNSET...TEMPS WILL FALL FAIRLY QUICKLY GIVEN DRY ATMOSPHERE...CLEAR SKIES AND LIGHT WINDS. MANY LOCATIONS WILL DIP INTO THE MU40S TONIGHT INCLUDING PLACES SUCH AS MARTHAS VINEYARD... NORWOOD AND OTHER INTERIOR EASTERN MA LOCATIONS. ALSO WESTERN MA AND SOUTHWEST NH SHOULD FALL INTO THE MU40S. ELSEWHERE MINS WILL BE IN THE LOW TO MID 50S. TRICKY PART TO THE FORECAST WILL BE IF SOME LOW CLOUDS ARE ABLE TO DEVELOP NEAR THE COAST TOWARD DAYBREAK. THESE CLOUDS MAY REAPPEAR TOWARD SUNRISE GIVEN BLYR COOLING OVERNIGHT. THUS COULD SEE SKIES BECOME PARTLY TO MOSTLY CLOUDY TOWARD DAYBREAK OVER EASTERN MA AND POSSIBLY INTO RI...BUT CONFIDENCE IS LOW. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... SATURDAY... DRY TO START THE DAY BUT QUICK MOVING NORTHERN STREAM SHORT WAVE TROUGH APPROACHES FROM THE WEST. TWO AREAS OF SHOWERS WILL TRACK ACROSS THE NORTHEAST. FIRST BATCH WILL BE OVER NY STATE AND NORTHERN NEW ENGLAND WITH PARENT LOW AND ACCOMPANYING LOW TO MID LEVEL JET. A SECOND AREA OF SHOWERS WILL TRACK SOUTH OF NEW ENGLAND AS LAST NIGHT/S FRONTAL BOUNDARY LIFTS NORTHWARD WITH SECONDARY LOW PRES DEVELOPING ON THE FRONT IN RESPONSE TO RRQ OF THE UPPER JET STREAK. THIS YIELDS LIKELY POPS ACROSS CAPE COD AND THE ISLANDS WITH CHANCE POPS ELSEWHERE FOR SCATTERED SHOWERS. GREATEST RISK OF SHOWERS IS SOMEWHERE BETWEEN 4-8 PM. COULD BE SOME HEAVIER SHOWERS ALONG SOUTH COAST AND OFFSHORE AS PWATS CLIMB TO 2 INCHES /+2 STD FROM CLIMO/. HOWEVER INSTABILITY ALOFT AND AT THE SURFACE IS LACKING SO HEAVIER SHOWERS AND THUNDER MAY BE WELL OFFSHORE. SYSTEM IS VERY PROGRESSIVE SO NOT EXPECTING A SOAKING RAIN. IN FACT SOME LOCATIONS MAY ONLY SEE A TRACE OF RAINFALL WITH OTHER LOCATIONS SUCH AS WELL INLAND AND ALONG THE SOUTH COAST PERHAPS A TENTH OR TWO. TEMPS A FEW DEGS COOLER THAN TODAY GIVEN THE COOLER START ALONG WITH INCREASING CLOUDS AND LIGHT ONSHORE WINDS. SATURDAY NIGHT... QUICK MOVING SYSTEM EXITS THE REGION BETWEEN 00Z WEST TO PERHAPS 03Z CAPE COD. EXPECT DECREASING CLOUDS AND DRIER AIR TO OVERSPREAD THE REGION. NORTHERLY WINDS WILL BECOME GUSTY LATE AT NIGHT AND TOWARD SUNRISE SUNDAY WITH A FEW GUSTS UP TO 25 MPH POSSIBLE. && .LONG TERM /SUNDAY THROUGH FRIDAY/... HIGHLIGHTS... * DRY WITH SLIGHTLY BELOW NORMAL TEMPS SUN/MON * LOW RISK OF PATCHY FROST SUN NIGHT ACROSS DISTANT INTERIOR * A PERIOD OF SHOWERS LIKELY LATE MON NIGHT/TUE * DRY WEATHER/SLIGHTLY BELOW NORMAL TEMPS NEXT WED-FRI DETAILS... SUNDAY AND MONDAY... LARGE HIGH PRESSURE WILL BE ANCHORED OVER SOUTHERN NEW ENGLAND SUN AND MON. THIS WILL RESULT IN DRY WEATHER WITH SLIGHTLY BELOW NORMAL HIGH TEMPS. HIGHS SUN AND MON WILL BE IN THE 60S...TO LOWER 70S. LOWS SUN NIGHT WILL BE QUITE CHILLY FOR MID SEPTEMBER. MAY SEE SOME MIDDLE TO UPPER 30S ACROSS PORTIONS OF SOUTHWEST NH/NORTHWEST MA... WHERE THIS IS A LOW RISK FOR SOME PATCHY FROST IN THE TYPICALLY COOLEST OUTLYING LOCATIONS. MOST OTHER AREAS WILL SEE LOWS IN THE 40S. MONDAY NIGHT AND TUESDAY... A POTENT SHORTWAVE/COLD FRONT WILL BE APPROACHING SOUTHERN NEW ENGLAND LATE MON NIGHT INTO TUE. THIS SHOULD RESULT IN A PERIOD OF RAIN SHOWERS...BUT EXACT TIMING IS UNCERTAIN AT THIS POINT. ITS POSSIBLE WE COULD EVEN SEE A PERIOD OF HEAVY RAIN IF THE MORE AMPLIFIED ECMWF MODEL IS CORRECT...BUT GFS/GGEM ARE A TAMER WITH THE SHORTWAVE SO THAT IS UNCERTAIN. INSTABILITY LOOKS FAIRLY LIMITED...SO WILL NOT INCLUDE THUNDER IN THE FORECAST AT THIS TIME. HIGHS SHOULD BE IN THE 60S TO AROUND 70. WEDNESDAY THROUGH FRIDAY... HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT WED INTO FRI. THIS SHOULD RESULT IN MAINLY DRY WEATHER WITH SLIGHTLY BELOW NORMAL TEMPS FOR THE END OF THE WORK WEEK. WE MAY HAVE TO DEAL WITH THE RISK FOR SOME FROST IN SOUTHWEST NH/NORTHWEST MA...WHERE WINDS CAN DECOUPLE. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TONIGHT... HIGH CONFIDENCE. VFR THEN LOWERING CONFIDENCE TOWARD SUNRISE SAT AS CIGS BKN020-030 POSSIBLE EASTERN MA INTO RI. WILL ONLY GO SCT025 FOR NOW GIVEN LOW CONFIDENCE. LIGHT EAST-NORTHEAST WINDS. SATURDAY... AS MENTIONED ABOVE LOW CONFIDENCE ON MORNING CIGS BKN025 ACROSS EASTERN MA AND RI. HIGHER CONFIDENCE THESE MVFR CIGS BKN025 BECOME MORE WIDESPREAD DURING THE AFTERNOON. SCATTERED SHOWERS MOST LIKELY AFTER 18Z FROM WEST TO EAST. SAT NIGHT... MVFR CIGS IN SCATTERED SHOWERS IMPROVING TO VFR BY 03Z WEST AND BY 06Z EAST. MODEST NNE WIND DEVELOPS 06Z-12Z WITH GUSTS UP TO 20-25 KT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. ONLY EXCEPTION IS POSSIBLE CIGS BKN020-030 LATE TOWARD SUNRISE SAT. GIVEN LOW CONFIDENCE HERE WENT WITH SCT025. THINKING CIGS BKN025 WAITS UNTIL THE AFTERNOON. GREATEST RISK OF SHOWERS 20Z SAT THRU 03Z SUN. KBDL TERMINAL...HIGH CONFIDENCE. GREATEST RISK OF SHOWERS 18Z SAT THRU 00Z SUNDAY. OUTLOOK...SUNDAY THROUGH WEDNESDAY...MODERATE TO HIGH CONFIDENCE. MAINLY VFR CONDITIONS OVER THIS TIME...EXCEPT FOR A PERIOD OF MVFR-IFR CONDITIONS LATE MON NIGHT/TUE IN A ROUND OF SHOWERS AND PERHAPS SOME LOW CLOUDS/FOG PATCHES. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. FORECAST CONFIDENCE IS HIGH THROUGH SATURDAY NIGHT. TONIGHT...TRANQUIL WEATHER WITH HIGH PRES BUILDING INTO SOUTHEAST QUEBEC AND MAINE. LIGHT EAST TO NORTHEAST WINDS...DRY WEATHER AND GOOD VSBY. SATURDAY...LIGHT NORTHEAST WINDS BECOME VARIABLE AS ONE AREA OF LOW PRES TRACKS NE INTO NY STATE AND ANOTHER WEAK LOW FORMS OFF THE NJ COAST. CHANCE OF SHOWERS LATE IN THE DAY WITH A LOW RISK OF THUNDER WELL SOUTH OF NEW ENGLAND. SAT NIGHT...WEAK LOW PRES EXITS EASTWARD ACROSS GEORGES BANK AND TOWARD THE MARITIMES BY SUNRISE SUNDAY. A MODEST NORTH WIND DEVELOPS WITH A LOW RISK OF GUSTS UP TO 25 KT LATE. SCATTERED SHOWERS DURING THE EVENING GIVES WAY TO DRY WEATHER AND GOOD VSBY. OUTLOOK...SUNDAY THROUGH WEDNESDAY.... SUNDAY...MODERATE TO HIGH CONFIDENCE. MAY HAVE SOME MARGINAL SCA NORTHERLY WIND GUSTS/SEAS ACROSS THE EASTERN WATERS SUN MORNING IN THE COOL ADVECTION PATTERN. WINDS/SEAS SHOULD DIMINISH SUN AFTERNOON AS PRESSURE GRADIENT WEAKENS. MONDAY INTO TUE MORNING...MODERATE TO HIGH CONFIDENCE. HIGH PRESSURE NEARBY WILL RESULT IN A WEAK PRESSURE GRADIENT KEEPING WINDS/SEAS BELOW SCA THRESHOLDS. TUESDAY AFTERNOON INTO WEDNESDAY...MODERATE CONFIDENCE. MAY SEE SOME MARGINAL SCA WINDS/SEAS ACROSS THE OUTER-WATERS BEHIND A COLD FRONT/LOW PRESSURE SYSTEM IN THE COOL AIR ADVECTION PATTERN. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/FRANK NEAR TERM...FRANK/NOCERA SHORT TERM...NOCERA LONG TERM...FRANK AVIATION...NOCERA/FRANK MARINE...NOCERA/FRANK

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