Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 301859 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 259 PM EDT WED JUL 30 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 /THROUGH TONIGHT/...
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200 PM UPDATE...ONLY MINOR ADJUSTMENTS TO TEMPERATURES AND SKY COVER TO ACCOUNT FOR LATEST TRENDS NEEDED THIS AFTERNOON. FOR TONIGHT...A WEAK HIGH PRESSURE WILL RESULT IN LIGHT WINDS. ALONG WITH PARTLY CLOUDY SKIES...PATCHY FOG SHOULD ONCE AGAIN DEVELOP. THE RELATIVELY DRY AIRMASS SHOULD ALLOW MIN TEMPERATURES TO BE UNSEASONABLY COOL ONCE MORE. USED A BLEND OF THE MOS GUIDANCE.
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&& .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
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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.
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/...
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HIGHLIGHTS... * A FEW SHOWERS POSSIBLE ON FRIDAY * STEADY RAIN LIKELY SOMETIME THIS WEEKEND * SHOWERS AND THUNDERSTORMS POSSIBLE EARLY NEXT WEEK THE MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE LONG TERM. THERE ARE DIFFERENCES IN THE DETAILS OF COURSE BUT OVERALL THE SYNOPTIC SCALE PATTERN IS FAIRLY WELL MODELED. USED A BLEND OF AVAILABLE GUIDANCE FOR MUCH OF THE FORECAST. THE HIGH AMPLITUDE UPPER LEVEL TROUGH ACROSS THE EASTERN U.S. IS THE DOMINANT FEATURE THROUGH THE EARLY PART OF THE LONG TERM. FRIDAY...THE COMBINATION OF A SHORTWAVE AND ABNORMALLY COLD AIR AT 500MB MAY BE ENOUGH TO SPARK SOME SHOWERS AND PERHAPS A THUNDERSTORM...BUT MUCH OF THE DAY SHOULD BE DRY. SATURDAY AND SUNDAY...THE TROUGH SHIFTS A BIT TO THE WEST OVER THE WEEKEND ALLOWING FOR SUBTROPICAL MOISTURE TO MOVE UP THE EAST COAST. THIS ALLOWS A STATIONARY FRONT OFF THE COAST TO SHIFT WEST OVER SOUTHERN NEW ENGLAND. COMBINED WITH THE MOISTURE...EXPECT A FAIRLY STEADY RAINFALL ACROSS AT LEAST A PORTION OF SOUTHERN NEW ENGLAND THROUGH PART OF THE WEEKEND. THERE ARE SOME DIFFERENCES IN THE MODELS BOTH IN THE WESTWARD EXTENT OF THE FRONT AND IN THE TIMING SO THIS COULD OCCUR SATURDAY...SUNDAY...OR A PORTION OF BOTH DAYS. MONDAY AND TUESDAY...STATIONARY FRONT SLOWLY SHIFTS BACK OFFSHORE BRINGING AN END TO THE STEADY RAINFALL. HOWEVER...LOW PRESSURE MOVING THROUGH QUEBEC WILL BRING A COLD FRONT TOWARDS SOUTHERN NEW ENGLAND. EXPECT THE POSSIBILITY FOR SHOWERS AND THUNDERSTORMS PERIODICALLY.
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&& .AVIATION /18Z WEDNESDAY 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 THURSDAY... THROUGH 00Z...HIGH CONFIDENCE. VFR CONDITIONS DESPITE SCATTERED TO BROKEN DECK OF MID LEVEL CLOUDINESS. SEA BREEZES DEVELOP THIS AFTERNOON ALONG PORTIONS OF THE IMMEDIATE COAST. TIMING AGAIN IS THE MOST UNCERTAIN FACTOR. TONIGHT AND THURSDAY...HIGH CONFIDENCE. PATCHY LATE NIGHT LOW CLOUDS AND FOG WITH LOCAL IFR POSSIBLE. MAINLY VFR CONDITIONS. A FEW HIT AND MISS SHOWERS/THUNDERSTORMS ARE EXPECTED DURING THE DAY THURSDAY ACROSS THE INTERIOR...WHICH MAY RESULT IN BRIEFLY LOWER CIGS/VSBYS. THURSDAY NIGHT...MODERATE CONFIDENCE. MAINLY VFR...WITH LOCAL IFR IN LOW CLOUDS AND PATCHY FOG. KBOS TAF...HIGH CONFIDENCE IN TAF. MODERATE CONFIDENCE IN END TIME OF SEA BREEZE THIS EVENING. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...FRIDAY THROUGH SUNDAY... FRIDAY...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF A BRIEF PERIOD OF MVFR CONDITIONS IN -SHRA. SATURDAY AND SUNDAY...MODERATE CONFIDENCE. MAINLY VFR NW...CHANCE FOR MVFR CIGS/VSBYS IN SCATTERED SHOWERS. MVFR CONDITIONS MORE PROBABLE TOWARDS EASTERN MA/RI IN -SHRA.
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&& .MARINE...
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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 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 SUNDAY... 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.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/RLG NEAR TERM...BELK SHORT TERM...BELK LONG TERM...RLG AVIATION...BELK/RLG MARINE...BELK/RLG

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