Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 312343 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 743 PM EDT THU JUL 31 2014 .SYNOPSIS... A FEW HIT AND MISS SHOWERS/THUNDERSTORMS ARE EXPECTED THIS EVENING ACROSS SOUTHERN NH AND WESTERN MA. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED AGAIN FRIDAY AFTERNOON...MAINLY NORTHWEST OF I-95. THE WEEKEND FORECAST REMAINS UNCERTAIN...BUT THE POTENTIAL FOR PERIODS OF WET WEATHER CONTINUES. SEASONABLE TEMPERATURES ARE THEN EXPECTED EARLY NEXT WEEK && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 730 PM UPDATE... CAPE VALUES CONTINUE TO DECLINE...AND A MID LEVEL SHORTWAVE MOVES FARTHER EAST FROM OUR REGION. EXPECTING THE LAST OF THE SHOWERS THIS EVENING TO DIMINISH OR MOVE EAST OF SOUTHERN NH AND NORTHERN MA BY 9-10 PM. OTHER THAN THAT...THE PRIMARY FORECAST THEME REMAINS ON TRACK. MADE SOME TWEAKS TO NEAR TERM CONDITIONS TO REFLECT LATEST OBSERVATIONS. PREVIOUS DISCUSSION... TONIGHT...DIURNAL CONVECTION ENDS EARLY...WITH HIGH PRESSURE CENTERED OFFSHORE WINDS ARE EXPECTED TO BECOME LIGHT SW. THERE MAY BE PATCHY LINGERING CONVECTIVE DEBRIS CLOUDS THAT CROSS OUR AREA...OTHERWISE MOSTLY CLEAR SKIES EXPECTED TONIGHT. GOOD RADIATIONAL COOLING WITH WINDS BECOMING LIGHT...TEMPS SHOULD DIP INTO THE MID 50S TO LOW 60S ACROSS MOST LOCALES. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FRIDAY...HIGH PRESSURE REMAINS CENTERED OFFSHORE...WITH A DEEP UPPER TROUGH LINGERING OVER EASTERN CANADA INTO THE GREAT LAKES REGION AND MISSISSIPPI VALLEY. THIS PLACES OUR AREA IN SW FLOW...AND THE MODELS ARE INDICATING A MOISTURE RICH ENVIRONMENT UPSTREAM IN THE SOUTHEASTERN U.S. THIS WILL BRING A GRADUAL INCREASE IN MOISTURE ACROSS OUR AREA FRIDAY INTO FRIDAY NIGHT. DURING FRIDAY SOME AFTERNOON DIURNAL CONVECTION IS POSSIBLE...CAPE INCREASING TO A FEW HUNDRED J/KG ACROSS THE INTERIOR. A SHORT WAVE MOVING THROUGH THE AREA MAY ASSIST AS A TRIGGER. SHEAR IS LESS THAN TODAY AND 500 MB TEMPS ARE NOT AS COLD. FRIDAY NIGHT...INCREASING MOISTURE CONTINUES. AN OFFSHORE FRONT IS EXPECTED TO BACK WESTWARD TOWARDS OUR COASTLINE...AND MODELS INDICATE THE POTENTIAL FOR AN OPEN WAVE DEVELOPING ALONG THIS FRONT. OVER THE COURSE OF THE NIGHT INCREASING CLOUDS ARE EXPECTED...WITH RAIN/SHOWERS POSSIBLE LATE. THERE IS SOME UNCERTAINTY ON THE PLACEMENT OF THE LOW FOR 12Z SAT...GENERALLY BETWEEN THE CAROLINAS AND MID ATLANTIC COASTLINE. && .LONG TERM /SATURDAY THROUGH THURSDAY/... HIGHLIGHTS... * STEADY RAIN LIKELY SOMETIME THIS WEEKEND * SHOWERS AND THUNDERSTORMS POSSIBLE EARLY NEXT WEEK THE MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH MOST OF THIS PORTION OF THE FORECAST. HOWEVER...THERE ARE DEFINITELY DIFFERENCES BOTH IN THE DETAILS AND ALSO IN PARTS OF THE SYNOPTIC PATTERN...PARTICULARLY AROUND THE POTENTIAL SYSTEM THIS WEEKEND. USED A BLEND OF AVAILABLE GUIDANCE FOR MUCH OF THIS PORTION OF THE FORECAST. SATURDAY AND SUNDAY...A MID LEVEL TROUGH SHIFTS A BIT TO THE WEST THIS WEEKEND...ALLOWING FOR SUBTROPICAL MOISTURE TO MOVE UP THE EAST COAST. THIS WESTWARD SHIFT DRAGS A NEARLY STATIONARY FRONT WEST TOWARD SOUTHERN NEW ENGLAND. COMBINED WITH THE MOISTURE... EXPECTING A FAIRLY STEADY RAINFALL ACROSS AT LEAST A PORTION OF SOUTHERN NEW ENGLAND THROUGH PART OF THIS WEEKEND. THERE ARE STILL DIFFERENCES IN THE MODELS...BOTH IN THE WESTWARD EXTENT OF THIS FRONT AND IN ITS TIMING. DEPENDING ON THE ULTIMATE RESOLUTION OF THESE DETAILS...THE FORECAST COULD REQUIRE SIGNIFICANT CHANGES. MONDAY AND TUESDAY...STATIONARY FRONT SLOWLY SHIFTS BACK OFFSHORE BRINGING AT LEAST A TEMPORARY END TO THE RISK FOR STEADY RAINFALL. HOWEVER...LOW PRESSURE MOVING THROUGH QUEBEC WILL BRING A COLD FRONT TOWARDS SOUTHERN NEW ENGLAND. EXPECTING THE POSSIBILITY FOR SHOWERS AND THUNDERSTORMS PERIODICALLY. WEDNESDAY...HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT. COOLER BUT QUIET WEATHER IS EXPECTED. THURSDAY...ANOTHER WAVE OF LOW PRESSURE ARRIVES FROM THE WEST...PUSHING A FRONT CLOSER TO OUR REGION. THIS SHOULD LEAD TO A SLIGHT INCREASE IN RAINFALL CHANCES. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT... TONIGHT...MODERATE CONFIDENCE. MAINLY VFR CONDITIONS OTHER THAN PATCHY GROUND FOG POSSIBLE LATE IN THE TYPICALLY PRONE LOCATIONS. SHRA SHOULD DIMINISH BY 01/02Z. 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. FRIDAY NIGHT...MODERATE CONFIDENCE VFR CONDITIONS. LOW CHANCE OF MVFR CIGS/VSBYS IN SCATTERED SHOWERS. KBOS TAF...HIGH CONFIDENCE IN VFR CONDITIONS. SEA BREEZE IS EXPECTED TO DEVELOP DURING FRIDAY TOWARDS MIDDAY. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...SATURDAY THROUGH TUESDAY... SATURDAY THROUGH SUNDAY...MODERATE CONFIDENCE. MAINLY VFR NW...CHANCE FOR MVFR CIGS/VSBYS IN SCATTERED SHOWERS. MVFR CONDITIONS MORE PROBABLE TOWARDS EASTERN MA/RI IN -SHRA. MONDAY AND TUESDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR/IFR CONDITIONS IN SCT -SHRA/TSRA...MAINLY DURING THE AFTERNOON AND EVENING HOURS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TODAY THROUGH FRIDAY NIGHT... HIGH CONFIDENCE. UPPER LEVEL RIDGE JUST EAST OF THE WATERS WILL KEEP WINDS/SEAS BELOW SMALL CRAFT ADVISORY LEVELS THROUGH FRIDAY AFTERNOON WITH GOOD VISIBILITIES. IN ADDITION...WINDS/SEAS EXPECTED TO REMAIN BELOW SCA THRESHOLDS FRIDAY NIGHT. OUTLOOK...SATURDAY THROUGH TUESDAY... HIGH CONFIDENCE. RELATIVELY QUIET BOATING WEATHER EXPECTED WITH RESPECT TO WINDS AND SEAS. RAIN IS LIKELY FOR A TIME THROUGH SUNDAY...AS A WAVERING STATIONARY FRONT NEAR OR OVER THE WATERS. THE MAIN IMPACT WILL BE REDUCED VISIBILITY. DRIER WEATHER EXPECTED BOTH MONDAY AND TUESDAY...WITH ONLY THE THREAT OF AN ISOLATED SHOWER OR TWO ACROSS THE WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/NMB NEAR TERM...BELK/NMB SHORT TERM...NMB LONG TERM...BELK AVIATION...BELK/NMB MARINE...BELK/NMB

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