Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 310545 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 145 AM EDT THU JUL 31 2014 .SYNOPSIS... MAINLY DRY/PLEASANT WEATHER TODAY OTHER THAN PERHAPS A BRIEF PASSING SPRINKLE. A FEW SHOWERS AND PERHAPS A THUNDERSTORM OR TWO ARE POSSIBLE THU AND FRI...BUT MOST OF THE TIME WILL FEATURE DRY WEATHER. CONFIDENCE IS INCREASING IN A PERIOD OF STEADY RAIN SOMETIME THIS WEEKEND AS LOW PRESSURE TRACKS CLOSE TO THE COAST. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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145 AM UPDATE... THE SHOWERS EARLIER THIS EVENING ACROSS NEW YORK STATE HAVE FALLEN APART AND JUST A TOUCH OF MID LEVEL CLOUDINESS REMAINS. DRY WEATHER WILL CONTINUE ACROSS SOUTHERN NEW ENGLAND THROUGH DAYBREAK. LIGHT WINDS/RELATIVELY DRY AIR IN PLACE SHOULD ALLOW LOW TEMPS TO FALL BACK MAINLY INTO THE 50S BY DAYBREAK...WITH LOWER 60S EXPECTED IN THE URBAN HEAT ISLANDS OF BOSTON/PROVIDENCE.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/... A POTENT SHORTWAVE WILL BE MOVING INTO NORTHERN NEW ENGLAND THURSDAY. MARGINAL INSTABILITY WILL DEVELOP ACROSS OUR NORTHERN AND WESTERN ZONES...WITH CAPES ON THE ORDER OF 500 TO 1000 J/KG. 0 TO 6 KM SHEAR IS FAIRLY STRONG...AROUND 40 KNOTS. THE CORE OF THE 500 MB COLD POOL TEMPERATURES AROUND -18 TO -20C...WHICH IS QUITE COLD FOR THIS TIME OF YEAR. THE BEST DYNAMICS WILL BE TO OUR NORTH AND WEST. HOWEVER...ENOUGH PARAMETERS ARE IN PLACE FOR A FEW HIT OR MISS SHOWERS OR THUNDERSTORMS ACROSS THE INTERIOR...ESPECIALLY ACROSS NORTHWEST MA AND SOUTHWEST NH. WHILE INSTABILITY IS RATHER MARGINAL...THE COLD POOL ALOFT AND ROBUST SHEAR MAY RESULT IN A FEW STRONG STORMS PRODUCING SMALL HAIL AND/OR GUSTY WINDS. INSTABILITY WEAKENS THURSDAY NIGHT...SO SHOWERS AND THUNDERSTORM COVERAGE DECREASES THROUGH THE EVENING. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGHLIGHTS... * AN ISOLATED THUNDERSTORM IS POSSIBLE ON FRIDAY * VERY UNSETTLED PATTERN FOR THE WEEKEND * SHOWERS AND THUNDERSTORMS POSSIBLE EARLY NEXT WEEK MODELS AND CONFIDENCE... 12Z MODEL GUIDANCE IS STILL IN GOOD AGREEMENT WITH THE FORECAST. A STRONG TROUGH WILL DOMINATE ACROSS THE MIDWEST FOR THE REMAINDER OF THIS WEEK INTO THE WEEKEND. A STALLED FRONT OVER THE EASTERN SEABOARD WILL BE THE FOCUS FOR HEAVY RAIN FOR THE WEEKEND AS SEVERAL WAVES RIDE ALONG THIS FRONT. OUT WEST...AN UPPER LEVEL RIDGE WILL CONTINUE TO BUILD ACROSS THE WESTERN CONUS AND EVENTUALLY MOVE INTO THE PLAINS. THIS WILL ALLOW FOR THE UPPER LEVEL TROUGH TO TURN MORE ZONAL BY THE FIRST HALF OF THE WEEK. BECAUSE OF THE OVERALL AGREEMENT TRENDED TOWARDS A BLEND OF THE MODELS AND PREVIOUS FORECAST FOR THIS PACKAGE. FOR CONFIDENCE LEVEL...HAVE HIGH CONFIDENCE ON TRENDS FOR THIS FORECAST...BUT A LOW CONFIDENCE ON EXACT TIMING. DETAILS... FRIDAY... SOUTHWESTERLY FLOW WILL ALLOW FOR GULF MOISTURE TO BEGIN TO SEEP INTO THE REGION BY FRIDAY. TEMPERATURES WILL BE CLOSE TO AVERAGE WITH A MIXTURE OF CLOUDS AND SUN. MODELS TRY TO PUSH OUT SOME QPF BUT DO NOT HAVE A GOOD FEELING AS HIGH PRESSURE OUT EAST BUILD ALLOWING FOR AN INCREASE IN HEIGHTS. IN FACT SOME OF THE INSTABILITY PARAMETERS MOVE WESTWARD THROUGHOUT THE DAY. SO FOR NOW MENTIONED JUST ISOLATED THUNDERSTORMS...BUT WITH A LOWER CONFIDENCE. SATURDAY INTO SUNDAY... MAIN FOCUS ON THE FORECAST WAS FOCUS ON THE WEEKEND. GUIDANCE CONTINUES TO SHOW THAT A SLUG OF RAIN WILL IMPACT NEW ENGLAND SOMETIME DURING THE WEEKEND...BUT THERE IS STILL SOME DIFFERENCES IN TIMING. OVERALL A STALLED FRONT WILL BE DRAPED ACROSS THE EASTERN SEA BOARD AS A FEW WAVES RIDE ALONG THIS FRONT BRING UNSETTLED WEATHER TO THE REGION. APPEARS TO BE 2 DIFFERENT MODEL CAMPS...THE GFS/CANADIAN AND THE EC/ECENS/UKMET. THE GFS CAMP BRINGS THE HEAVIEST RAIN ON SUNDAY WHILE THE EC CAMP BRINGS IT IN DURING THE DAY ON SATURDAY. OVERALL UNIFORM SOUTHWESTERLY FLOW THROUGH THE LEVELS WILL ALLOW FOR THE FLOW TO TAP INTO THE GULF MOISTURE INCREASING THE PWATS CLOSE TO 2 INCHES...AND ALMOST 2 STANDARD DEVIATIONS AWAY. BOTH MODELS ARE ALSO SHOWING A GOOD 850 MB LLJ INTO THE FLOW AT RESPECTIVE TIMES FOR HEAVY RAIN TO OCCUR. ALSO BECAUSE OF THE INCREASING LLJ CANNOT RULE OUT A RUMBLE OF THUNDER. CONFIDENCE IS MODERATE TO HIGH THAT HEAVIER RAIN WILL OCCUR...JUST A MATTER OF FINE TUNING THE TIMING OF WHEN IT WILL IMPACT SOUTHERN NEW ENGLAND. WORK WEEK... UPPER LEVEL FLOW WILL BECOME MORE ZONAL BY THE BEGINNING OF THE WORK WEEK. HOWEVER APPEARS THAT THERE MAY BE SOME LINGERING SHOWERS ON MONDAY...WITH A BETTER SHOT ON TUESDAY AS FRONT SLIDES THROUGH THE REGION. HOWEVER TIMING OF THIS SYSTEM MAY CHANGE AS IT IS STILL 6-7 DAYS AWAY. && .AVIATION /06Z THURSDAY THROUGH MONDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TODAY THROUGH FRIDAY... TODAY...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS. A FEW HIT AND MISS SHOWERS/THUNDERSTORMS EXPECTED THIS AFTERNOON...MAINLY TO THE NORTHWEST OF I-95 WITH THE HIGHEST RISK ACROSS NORTHWEST MA/SOUTHWEST NH. THIS ACTIVITY MAY RESULT IN BRIEFLY LOWER CIGS/VSBYS. TONIGHT...MODERATE TO HIGH CONFIDENCE. MAINLY VFR CONDITIONS OTHER THAN PATCHY GROUND FOG POSSIBLE LATE IN THE TYPICALLY PRONE LOCATIONS. FRIDAY...HIGH CONFIDENCE IN MAINLY VFR CONDITIONS. A FEW HIT AND MISS SHOWERS AND THUNDERSTORMS POSSIBLE DURING THE AFTERNOON...MAINLY NORTHWEST OF I-95. THIS ACTIVITY MAY RESULT IN BRIEFLY LOWER CONDITIONS. KBOS TAF...HIGH CONFIDENCE IN VFR CONDITIONS WITH MODERATE CONFIDENCE THAT A SOUTHEAST SEA BREEZE DEVELOPS FOR A FEW HOURS THIS AFTERNOON. VERY LOW PROBABILITY FOR A THUNDERSTORM MOVING OVER THE TERMINAL THIS AFTERNOON. KBDL TAF...HIGH CONFIDENCE IN TAF. LOW PROBABILITY FOR A BRIEF THUNDERSTORM TO MOVE ACROSS THE TERMINAL THIS AFTERNOON. OUTLOOK...FRIDAY NIGHT THROUGH SUNDAY... SATURDAY AND SUNDAY...MODERATE CONFIDENCE. MVFR CIGS/VSBYS IN SCATTERED SHOWERS. POSSIBLE MVFR/IFR CONDITIONS MORE PROBABLE TOWARDS EASTERN MA/RI IN -RA AND ISO THUNDER. MONDAY...MODERATE CONFIDENCE. CONDITIONS IMPROVING TO VFR.
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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...TODAY THROUGH THURSDAY NIGHT... HIGH CONFIDENCE. WINDS/SEAS SHOULD GENERALLY REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THROUGH THURSDAY NIGHT ALONG WITH GOOD VISIBILITIES. LOW RISK OF MARGINAL 5 FOOT SWELL REACHING INTO THE SOUTHERN AND EASTERN ATLANTIC WATERS TONIGHT AND THURSDAY FROM A DISTANT OFFSHORE LOW PRESSURE. BASED ON MOST WAVE GUIDANCE... CAPPED SEAS AT 4 FEET FOR NOW BUT LATER SHIFTS WILL HAVE TO REEVALUATE. OUTLOOK...FRIDAY THROUGH MONDAY... FRIDAY...HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE OVER THE WATERS. SATURDAY AND SUNDAY...MODERATE CONFIDENCE. WINDS AND SEAS ARE FORECAST TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. HOWEVER...MORE UNSETTLED WEATHER IS LIKELY WITH A STATIONARY FRONT WAVERING OVER THE WATERS. BRING SEVERAL ROUNDS OF RAIN AND ISOLATED THUNDER. MONDAY...MODERATE CONFIDENCE. IMPROVING VSBY CONDITIONS WITH SEAS/WINDS STILL BELOW SCA. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...FRANK SHORT TERM...BELK LONG TERM...DUNTEN AVIATION...FRANK/DUNTEN MARINE...BELK/DUNTEN

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