Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 280506 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 106 AM EDT SUN SEP 28 2014 .SYNOPSIS... ANOTHER DAY OF SUMMERLIKE WARMTH IS AHEAD TODAY AS HIGH PRESSURE HEADS OFF THE COAST. A FRONT WILL DROP SOUTH ACROSS THE REGION MONDAY...FOLLOWED BY A COOLER NORTHEAST FLOW AND PERHAPS A BRIEF SHOWER. A COASTAL LOW PRESSURE SYSTEM WILL DEVELOP BUT STAY TO THE SOUTH OF THE REGION DURING THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... 105 AM UPDATE... PATCHY DENSE FOG HAS BEGUN TO FORM ONCE AGAIN...PRIMARILY ACROSS PARTS OF CT RIVER VALLEY...INTERIOR E MA AND UPPER CAPE. EXPECT THIS TO PERSIST THROUGH A LITTLE PAST SUNRISE AS TEMPERATURES DROP INTO 40S AND 50S. AFTER FOG BURNS OFF...ANOTHER DAY WITH PLENTY OF SUNSHINE IS AHEAD. MORE OF S/SW FLOW IN PLACE TODAY WITH HIGH PRESSURE OFF COAST...BUT GRADIENT LOOKS TO BE WEAK ENOUGH TO ALLOW FOR FEW HOURS OF SEA BREEZES ALONG BOTH COASTS. HIGHS WILL RUN A FEW DEGREES WARMER THAN YESTERDAY GIVEN TEMPERATURES ALOFT...WHICH SHOULD REACH MID 80S AWAY FROM COAST. RECORD HIGHS AT PROVIDENCE...WINDSOR LOCKS AND PERHAPS WORCESTER WILL BE CHALLENGED TODAY /SEE CLIMATE SECTION BELOW/. && .SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/... SHOULD BE A MILDER NIGHT TONIGHT WITH BROAD S/SW FLOW IN PLACE... OTHERWISE CLEAR SKIES WITH A RETURN OF PATCHY DENSE FOG IN LOW LYING AREAS. LOWS WILL DROP BACK INTO 50S AND LOWER 60S. TIMING OF COLD FRONT DROPPING S THROUGH REGION MON IS HANDLED WELL BY 00Z MODELS. IT SHOULD REACH MA/NH BORDER 12Z-15Z...PUSH THROUGH BOSTON AND MASS PIKE CORRIDOR BY 18Z THEN MUCH OF CT...RI AND SE MA BY 21Z OR SO. INCREASING NE FLOW BEHIND FRONT WILL AFFECT MUCH OF E MA MON AFTERNOON...SO HIGHS FROM BOSTON TO NE MA WILL OCCUR LATE IN MORNING...BEFORE READINGS DROP DURING AFTERNOON. IN FACT NAM 2M TEMPERATURES FALL INTO UPPER 50S BY EVENING AROUND CAPE ANN. FARTHER INLAND...IT IS USUALLY DIFFICULT FOR COOLER AIR TO PENETRATE MUCH PAST WORCESTER HILLS SO WARMEST READINGS WILL BE FOUND IN WESTERN NEW ENGLAND. NOT EXPECTING MUCH IN WAY OF SHOWERS AS FRONT PUSHES THROUGH... ESPECIALLY GIVEN LACK OF SIGNIFICANT LIFT AND DEEP MOISTURE AS SEEN ON FORECAST CROSS SECTIONS. INCLUDED MENTION OF ISOLATED SHOWERS BUT ANY ACTIVITY SHOULD BE BRIEF AND NOT PRODUCE MUCH IN WAY OF RAINFALL. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... HEADLINES... *A CHANCE OF SHOWERS MONDAY NIGHT INTO TUESDAY *UNCERTAIN FORECAST AFTER MONDAY *COASTAL LOW MAY DEVELOP MIDWEEK OFF SOUTHEAST COAST OVERVIEW... THE GENERAL PATTERN BEGINS WITH SPLIT FLOW AROUND A CUTOFF LOW PRESSURE SYSTEM IN THE WESTERN US. THIS IS THE WESTERN EDGE OF A WAVE TRAIN. IN THE EASTERN US...A TROUGH EXISTS. AS THE PATTERN EVOLVES...THE RIDGE MOVES EAST INTO THE EASTERN US WITH A TROUGH OVER THE WESTERN US FOR A VERY HIGH AMPLITUDE PATTERN WITH STRONG BLOCKING IN EASTERN CANADA. THE MODELS ARE HAVING TROUBLE HANDLING THE TIMEFRAME FROM TUESDAY ON THROUGH THE END OF THE PERIOD. A COASTAL LOW FORMS OFF THE MID ATLANTIC COAST...BUT DISCREPANCIES OCCUR IN THE TRACK AND INTENSITY DEPARTMENTS MAINLY BECAUSE THE MODELS AREN/T HANDLING THE LOCATION AND INTENSITY OF THE RIDGE OVER SOUTHEASTERN CANADA. DAILIES... TUESDAY THROUGH THURSDAY...AS THE ENERGY FROM MONDAY/S COLD FRONT MOVES INTO THE UNITED STATES...ENERGY FROM THE SOUTHEASTERN US AND THAT COLD FRONT INTERACT TO CREATE A COASTAL LOW PRESSURE SYSTEM. HOWEVER...VERY DIFFERENT SOLUTIONS ENSUE. THE 00Z ECMWF HAS CUTOFF THE ENERGY AS IT IS WONT TO DO WHILE THE 6Z GFS/00Z CANADIAN HAVE NOT AND HAVE THE LOW PRESSURE SYSTEM FURTHER SOUTH. AM LEANING AWAY FROM THE ECMWF ON THIS FORECAST. AM ALSO NOTING THAT THE GEFS SHOWS VERY LOW PROBABILITY OF PRECIPITATION...WHICH MAY BE FROM SPREAD...BUT ALSO FROM MOST MEMBERS SHOWING NO PRECIPITATION. WITH A STRONGER RIDGE TO THE NORTH ESPECIALLY INDICATED IN THE GFS BY THE LOW RH AT 700 MB...BELIEVE THAT MOST OF THE PRECIPITATION WILL STAY SOUTH...BUT COULD STILL HAVE A CHANCE OF PRECIPITATION ESPECIALLY ALONG THE SOUTH COAST OF SOUTHERN NEW ENGLAND. THIS IS ENFORCED BY THE NEW 12Z ECMWF THAT CAME IN DRY FOR THE REGION. AGREE WITH PREVIOUS FORECASTER IN SAYING THE ONLY AGREEABLE PORTIONS OF THIS FORECAST IS THAT NORTHEAST WINDS WILL DEVELOP ALLOWING FOR CLOUDS AND COOLER TEMPERATURES DURING THIS PERIOD. FRIDAY...WITH THE COASTAL LOW NOW OUT TO SEA...HIGH PRESSURE OCCURS AHEAD OF AN APPROACHING COLD FRONT. HAVE GONE AWAY FROM DETERMINISTIC GUIDANCE FOR FRIDAY AND SATURDAY. SATURDAY...ANOTHER TROUGH APPROACHES FROM THE WEST AND A COLD FRONT LOOKS TO MOVE OVER THE REGION. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...HIGH CONFIDENCE THROUGH MON. LOCALIZED IFR/LIFR IN PATCHY DENSE FOG THROUGH DAYBREAK... MAINLY DUE TO VSBY. OTHERWISE VFR TODAY WITH LIGHT S/SW FLOW. SEA BREEZES SHOULD DEVELOP AROUND MIDDAY ALONG BOTH COASTS...THOUGH IT WILL BE WEAK ALONG E MA COAST AND PROBABLY WILL NOT GET VERY FAR INLAND. PATCHY FOG EXPECTED ONCE AGAIN TONIGHT BUT ANY IFR/LIFR WILL BE LOCALIZED...LESS SO THAN THIS MORNING. COLD FRONT DROPS S ACROSS REGION MON WITH WIND SHIFT TO N/NE. TIMING IS 12Z-15Z ALONG MA/NH BORDER...AROUND 18Z BAF-ORH-BOS... BY 21Z BDL-PVD-PYM AND CLOSER TO 00Z TUE ALONG S COAST...CAPE COD AND ISLANDS. VFR CIGS 040-050 AHEAD OF FRONT BUT EXPECT CIGS TO LOWER TO MVFR BEHIND IT...MAINLY LATE IN DAY ACROSS S NH AND N MA. MAY ALSO BE ISOLD SHOWER. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE ONSET SHOULD BE A BIT LATER THAN USUAL...MORE LIKE 16Z-18Z...AND IT MAY BE WEAK ENOUGH THAT IT MAY REMAIN OVER BOS HARBOR OR ON E END OF AIRPORT. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...MONDAY NIGHT THROUGH THURSDAY... MONDAY NIGHT-TUESDAY...MODERATE CONFIDENCE. VFR. COLD FRONT MAY BRING SCATTERED SHOWERS WITH LOCAL MVFR CIGS/VSBYS POSSIBLE. AREAS WHERE RAIN FALLS COULD ALSO SEE FOG FORM. NE WINDS MAY PICK UP ALONG THE IMMEDIATE E COAST OVERNIGHT...GUSTS TO AROUND 20 KT POSSIBLE FROM KBOS TO KBVY. TUESDAY NIGHT THROUGH THURSDAY...MODERATE CONFIDENCE. MAINLY VFR... THOUGH COULD SEE PATCHY MVFR CIGS ESPECIALLY ALONG THE COAST WITH PERSISTENT ONSHORE WINDS. WIDELY SCT SHOWERS MAY LINGER ACROSS REGION WITH THE MOIST AIRMASS IN PLACE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...HIGH CONFIDENCE THROUGH MON. HIGH PRESSURE MOVES OFFSHORE TODAY WITH LIGHT S/SW FLOW AND FLAT SEAS THROUGH TONIGHT. WEAK SEA BREEZES DEVELOP AROUND MIDDAY. COLD FRONT PUSHES S ACROSS WATERS MON...FIRST NEAR MERRIMACK RIVER IN MORNING AND PROBABLY NOT REACHING S COAST UNTIL LATE AFTERNOON. SW WINDS GIVE WAY TO WIND SHIFT TO N/NE BEHIND FRONT...AND MAY REACH 25 KT LATE IN DAY FROM BOSTON TO MERRIMACK RIVER AS SEAS BUILD TO 3 TO 5 FT. SCA MAY BE NEEDED FOR THESE AREAS. OUTLOOK...MONDAY NIGHT THROUGH THURSDAY... MONDAY NIGHT...MODERATE CONFIDENCE. COLD FRONT MOVES S INTO THE REGION. GUSTY NE WINDS MOVE IN ACROSS THE EASTERN WATERS WITH GUSTS UP TO 25 KT POSSIBLE. SEAS MAY ALSO BUILD ON THE OPEN WATERS...POSSIBLY UP TO 5-6 FT E OF CAPE ANN TO E OF BOSTON HARBOR. SCA MAY BE NEEDED THERE. TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE. PERSISTENT NE WINDS REMAIN IN PLACE AS POSSIBLE COASTAL LOW DEVELOPS OFF THE MID ATLC COAST. SEAS WILL BUILD UP TO 5-7 FT...HIGHEST ON THE OUTER WATERS LATE TUE NIGHT AND WED. VSBY RESTRICTIONS POSSIBLE ON THE SOUTHERN OUTER WATERS IN SCT SHOWERS AND PATCHY FOG. && .CLIMATE... RECORD HIGHS FOR TODAY 9/28 BOSTON.......... 90 IN 1881 AND PREVIOUS YEARS PROVIDENCE...... 84 IN 1943 WORCESTER....... 84 IN 1916 WINDSOR LOCKS... 83 IN 1959 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...EVT/JWD NEAR TERM...JWD SHORT TERM...JWD LONG TERM...99 AVIATION...EVT/JWD MARINE...EVT/JWD CLIMATE...STAFF

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