Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 171742 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 142 PM EDT FRI MAY 17 2013 .SYNOPSIS... A DRY NORTH TO NORTHWEST FLOW WILL PREVAIL TODAY BEHIND A COLD FRONT THAT WILL CONTINUE TO MOVE SOUTH OF NEW ENGLAND TODAY. HIGH PRESSURE PROVIDES DRY AND SEASONABLE WEATHER FOR MUCH OF THE WEEKEND. AN APPROACHING WARM FRONT WILL THEN INCREASE THE CHANCE OF RAIN FROM LATE SUNDAY INTO MONDAY. THE FRONT LIFTS NORTH OF THE AREA AROUND TUE OF NEXT WEEK YIELDING WARM...MORE HUMID AND SHOWERY WEATHER MUCH OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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140 PM UPDATE... AREA OF HIGH CLOUDS STREAMING ACROSS CT RI AND SE MA WILL SHIFT TO THE S BY LATE TODAY. OTHERWISE...SCT-BKN CU ACROSS EASTERN NEW ENG WILL DECREASE IN COVERAGE WITH LIFTING CLOUD BASES THROUGH THIS EVENING. BOUNDARY LAYER WINDS REMAIN STRONG ENOUGH TO HOLD OFF THE SEABREEZE BUT IT APPEARS THE WINDS WILL DIMINISH MID/LATE AFTERNOON WITH WEAK SEABREEZES STILL POSSIBLE.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... MOSTLY CLEAR SKIES AND LIGHT WINDS SHOULD AID RADIATIONAL COOLING AND MOST LOCATIONS BACK FROM THE IMMEDIATE COAST SHOULD DIP INTO THE 40S...PERHAPS UPPER 30S IN COLDER SPOTS OF SW NH AND NW MA. SATURDAY LOOKS TO BE DRY AS WELL...ALTHOUGH THERE MAY BE ENOUGH OF A COLD POOL ALOFT N AND E OF WORCESTER FOR POSSIBLY A FEW SPRINKLES. THINK IT IS TOO DRY FOR ANY MEASURABLE RAFL BUT DID PUT A SMALL AREA OF SLIGHT CHANCE POPS IN NE MA AND SOUTHERN NH FOR SATURDAY MID TO LATE AFTERNOON. AIR MASS LOOKS TO BE MODESTLY MILDER...BRINGING TEMPS INTO THE 70S ACROSS THE INTERIOR. LOOKS LIKE A LIGHT ENOUGH GRADIENT TO SUPPORT SEA BREEZES NEAR THE COAST. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGHLIGHTS... * CHANCE OF RAIN LATE IN THE WEEKEND * TREND TOWARD WARMER/MORE HUMID AND SHOWERY WEATHER NEXT WEEK LOW CONFIDENCE FORECAST ON THE DETAILS NEXT WEEK AS MODELS ARE NOW TRENDING TOWARD A MORE AMPLIFIED/BLOCK PATTERN...WITH THE NORTHERN STREAM BECOMING MORE DOMINANT WITH TIME ACROSS SOUTHEAST CANADA AND THE NORTHEAST. THE QUESTION THEN BECOMES HOW MUCH DOES THE NORTHERN STREAM ERODE THE SUBTROPICAL RIDGE ALONG THE EASTERN SEABOARD NEXT WEEK? THIS WILL DETERMINE THE LOCATION AND SOUTHEAST PROGRESSION OF A FRONTAL BOUNDARY...WHICH WILL BE CRITICAL IN DETERMINING TEMPERATURES AND PROBABILITY OF PRECIPITATION. INCREASING FORECAST UNCERTAINTY HERE IS THE LONG WAVE PATTERN ALSO BECOMES MORE OF A SPLIT FLOW REGIME...WHICH OFFERS LOW PREDICTABILITY GIVEN THE INCREASED FORECAST UNCERTAINTY WILL LEAN/FOLLOW ENSEMBLE GUID /16-12Z ECENS AND 17-00Z GEFS/ MORE THAN THE DETERMINISTIC MODELS FROM TUE ONWARD. SAT NIGHT/SUN BEGINS WITH MID LEVEL CLOSED LOW OVER ATLANTIC CANADA AND A CORRESPONDING MARITIME HIGH JUST EAST OF NEW ENGLAND. THIS WILL PROVIDE DRY AND SEASONABLE COOL CONDITIONS SAT NIGHT INTO SUN. SUN WILL BE COOLER THAN SAT. THEN BY LATE SUN INTO MON THE ATLANTIC CANADA MID LEVEL LOW MOVES SEAWARD ALLOWING A WARM FRONT SOUTH AND WEST OF NEW ENGLAND TO APPROACH THE AREA. THIS MAY RESULT IN SOME WARM ADVECTION PRECIP ACROSS THE REGION FROM LATE SUN /ESP SUN NIGHT/ INTO MON. A FEW HEAVIER SHOWERS ARE POSSIBLE DURING THIS TIME AS THE 00Z GEFS INDICATES PWATS OF +2 STD MAY ADVECT INTO SOUTHERN NEW ENGLAND. BY TUE AND/OR WED SOUTHERN NEW ENGLAND SHOULD BE IN THE WARM SECTOR SO A PERIOD OF WARMER MORE HUMID WEATHER IS LIKELY. THEN COMES THE MORE DIFFICULT PART OF THE FORECAST...HOW FAR SOUTHEAST WILL A FRONTAL BOUNDARY PROGRESS AS THE LONG WAVE TROUGH OVER SOUTHEAST CANADA RELOADS WITH YET ANOTHER CLOSED LOW PIVOTING INTO QUEBEC. THE 16/12Z ECENS AND 17/00Z GEFS SUGGEST THE FRONTAL BOUNDARY WILL REMAIN OVER OR JUST NORTHWEST OF SOUTHERN NEW ENGLAND MUCH OF NEXT WEEK. THIS SHOULD YIELD WARM AND SOMEWHAT HUMID WEATHER ALONG WITH A RISK OF MAINLY DIURNAL SHOWERS FROM TUE AND BEYOND. SO WHILE THE FORECAST FOR NEXT WEEK CONTAINS CHANCE POPS JUST ABOUT EVERY DAY...NOT EXPECTING A WASHOUT WITH MANY HOURS OF DRY WEATHER ANTICIPATED ESPECIALLY DURING THE OVERNIGHTS AND INTO THE MORNING HOURS. AS FOR TEMPS...WARMER THAN NORMAL FROM TUE ONWARD BUT NOT EXPECTING ANY RECORD HEAT. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE. HIGH CONFIDENCE OF VFR CONDITIONS THROUGH SAT NIGHT. N/NW WINDS WILL DIMINISH THROUGH THE AFTERNOON WITH LOCAL MID/LATE AFTERNOON SEABREEZES STILL POSSIBLE. KBOS TERMINAL...SEABREEZE STILL POSSIBLE BY 21Z AS LOW LEVEL WINDS DIMINISH...BUT CONFIDENCE IS A BIT LOWER. SEABREEZE MORE LIKELY SATURDAY. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SAT NIGHT THROUGH SUN...VFR LIKELY ALONG WITH DRY WEATHER AND LIGHT WINDS. HIGH CONFIDENCE. SUN NIGHT THROUGH TUE....MVFR-IFR IN PERIODS OF LIGHT RAIN POSSIBLY IMPROVING TO VFR TUE. MODERATE CONFIDENCE.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY/...HIGH CONFIDENCE. WINDS HAVE DROPPED BELOW SCA THRESHOLDS BUT A RESIDUAL SWELL REMAINS IN THE OUTER SE WATERS WHERE SCA TO CONTINUE INTO THE AFTERNOON. OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY... SAT NIGHT AND SUN...HIGH PRES OVER GULF OF ME PROVIDES DRY WEATHER WITH LIGHT WINDS AND GOOD VSBY. HIGH CONFIDENCE. SUN NIGHT AND MON...HIGH PRES MOVES OFFSHORE WITH SSW WINDS INCREASING. PERIODS OF LIGHT RAIN AND FOG POSSIBLE. MODERATE CONFIDENCE. TUE...SOME IMPROVEMENT POSSIBLE AS WARM FRONT LIFTS NORTH OF THE REGION. MODERATE CONFIDENCE. && .FIRE WEATHER... IT WILL BE DRY AGAIN TODAY WITH REL HUMIDITIES DROPPING MOST INTERIOR LOCATIONS TO 25 TO 30 PERCENT...BUT NOT AS LOW AS YESTERDAY WHEN TEMPS WERE ABOUT 10 DEGREES WARMER AND DEWPOINTS SEVERAL DEGREES LOWER AIDED BY DEEP MIXING. WINDS WILL BE MUCH LIGHTER TODAY. OVER THE WEEKEND WINDS BECOME ONSHORE /E TO SE/ AT 10 MPH OR LESS...WHICH WILL KEEP MINIMUM RELATIVE HUMIDITY NO LOWER THAN 30 TO 40 PERCENT. ASIDE FROM AN ISOLATED SHOWER...DRY WEATHER IS EXPECTED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ254-255. && $$ SYNOPSIS...NOCERA/THOMPSON NEAR TERM...KJC SHORT TERM...THOMPSON LONG TERM...NOCERA AVIATION...KJC/NOCERA MARINE...NOCERA/THOMPSON FIRE WEATHER...

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