Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 271828 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 228 PM EDT SUN JUL 27 2014 .SYNOPSIS...
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SCATTERED SHOWERS AND THUNDERSTORMS EARLY THIS AFTERNOON WILL TAPER OFF BY MID AFTERNOON. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL SWEEP ACROSS THE AREA MONDAY MORNING WITH A SECOND BATCH MONDAY AFTERNOON...AS LOW PRESSURE TRACKS FROM THE GREAT LAKES TO NEW ENGLAND AND EVENTUALLY PUSHES A COLD FRONT THROUGH THE REGION MONDAY NIGHT. THE COLD FRONT STALLS OVER THE MARITIMES AND NEW ENGLAND OFFSHORE WATERS FROM MIDWEEK THROUGH THE WEEKEND.
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&& .NEAR TERM /THROUGH TONIGHT/...
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230 PM UPDATE... *** HEAVY SHOWERS AND SCATTERED T-STORMS WILL EXIT EASTERN MA AND RI MID TO LATE AFTERNOON *** NOT MUCH CHANGE FROM PREVIOUS FORECAST/DISCUSSION AS WARM FRONTAL CONVECTION CONTINUES TO PUSH INTO EASTERN MA AND RI AT 2 PM. HEAVY RAINFALL AND GUSTY WINDS CAN BE EXPECTED IN A FEW OF THE STRONGER STORMS...THIS INCLUDES THE NORTH SHORE OF BOSTON. THIS ACTIVITY WILL MOVE OFFSHORE BY 3 OR 4 PM OR SO. FARTHER WEST ACROSS NY AND PA IN THE TRUE WARM SECTOR AIRMASS CLOUDS GIVE WAY TO BREAKS OF SUNSHINE. NOT MUCH CONVECTION IN THIS WARM SECTOR AS MID LEVEL RIDGING AND ASSOCIATED MID LEVEL DRY AIR ADVECTING ACROSS THIS REGION. THUS THIS WILL BE THE TREND FOR SOUTHERN NEW ENGLAND FOR THE REMAINDER OF THE AFTERNOON AND EARLY EVENING...WITH A TREND FOR THE RISK OF SHOWERS/TSTMS TO DIMINISH WITH TIME. TEMPS WILL RISE INTO THE LOWER 80S THE NEXT FEW HOURS AS SUNSHINE DEVELOPS FROM WEST TO EAST. QUITE MUGGY WITH DEW PTS 65 TO 70.
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&& .SHORT TERM /MONDAY/...
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*** LOCALIZED FLASH FLOODING POSSIBLE TONIGHT *** *** FEW SEVERE STORMS POSSIBLE AGAIN MON *** CONCERN FOR TONIGHT IS POTENTIAL FOR LOCALIZED FLASH FLOODING AND PERHAPS STRONG TO SEVERE STORMS...BUT AGAIN CONFIDENCE REMAINS MODERATE AT BEST IN HOW THINGS EVOLVE. ONCE ANY STORMS DIMINISH THIS EVENING...ATTENTION TURNS TO POTENTIAL MCS DEVELOPMENT UPSTREAM ACROSS OHIO VALLEY. HIGHER-RES MODELS INCLUDING 00Z NAM ARE MORE INSISTENT THAT ITS REMNANTS WILL TRACK NEAR OR OVER SOUTHERN NEW ENGLAND TONIGHT...PROBABLY NEAR S COAST IF NOT A BIT FARTHER INLAND. 00Z GFS SEEMS TO BE STRUGGLING MORE WITH THIS FEATURE...PROBABLY DUE TO ITS COARSER RESOLUTION... BUT ALSO HINTS AT SOME SORT OF ORGANIZED CONVECTION. WILL MAINTAIN LIKELY POPS FOR MUCH OF REGION TONIGHT. OVERALL SEVERE THREAT TONIGHT IS QUESTIONABLE AS WE REMAIN UNSTABLE BUT 0-3KM SHEAR AND LAPSE RATES DROP OFF A BIT. CERTAINLY MAIN THREAT APPEARS TO BE HEAVY RAIN WITH PLENTIFUL LOW LEVEL MOISTURE. FLASH FLOOD THREAT DOES NOT APPEAR TO BE WIDESPREAD ENOUGH TO ISSUE ANY WATCHES AT THIS TIME...NOR DO WE HAVE CONFIDENCE IN GREATEST THREAT AREA.MONDAY NIGHT...LINGERING AREAS OF MVFR/IFR IN THUNDERSTORMS. OTHERWISE VFR OR TRENDING TO VFR. WINDS SHIFT TO WEST AND DIMINISH. UPPER LOW CUTS OFF TO OUR W MON AS SURFACE LOW LIKELY PASSES JUST TO OUR W. THIS SHOULD FOCUS MOST OF SHOWERS/STORMS TO OUR W AND N WHERE BETTER LARGE SCALE FORCING RESIDES. WE MAY EVEN END UP WITH A DRY SLOT ACROSS SE NEW ENGLAND BUT PERSISTENT S/SW FLOW SHOULD MAINTAIN CLOUDINESS THERE. ONCE AGAIN THERE ARE QUESTIONS AS TO HOW MUCH CLEARING WE ACTUALLY SEE AND IF THAT GENERATES ENOUGH INSTABILITY FOR ADDITIONAL STORM DEVELOPMENT MON AFTERNOON. IF STORMS CAN DEVELOP...ENVIRONMENT WOULD FEATURE DECENT MID LEVEL LAPSE RATES AND STRONG 0-3KM SHEAR WHICH WOULD SUPPORT A FEW SEVERE STORMS. DUE TO CONTINUED UNCERTAINTY...USED BLEND OF GUIDANCE WHICH GIVES HIGHS IN 70S TO AROUND 80.
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&& .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... BIG PICTURE... MODELS CONTINUE TO ADVERTISE A MERIDIONAL TYPE FLOW THROUGH THE UPCOMING WEEK. FOUR LOBES OF THIS FLOW ARE THE GULF OF ALASKA TROUGH...WESTERN NORTH AMERICA RIDGE...EASTERN NORTH AMERICA TROUGH...AND WEST ATLANTIC RIDGE. THE EFFECT OF THIS PATTERN WILL BE TO BRING SIMILAR WEATHER EACH DAY. MODELS CONTINUE TO SHOW THE CORE OF THE EASTERN NO-AM TROUGH EJECTING NORTH THROUGH QUEBEC FRIDAY AND SATURDAY. THIS MAY LEAVE ROOM FOR THE ATLANTIC RIDGE TO SHIFT WEST BY SATURDAY. THE SIMILARITY IN MODEL FIELDS FAVORS A BLEND OF AVAILABLE DATA. THE DAILIES... MONDAY NIGHT... SURFACE LOW PRESSURE LIFTS NORTH INTO CANADA...ALL THE WHILE SWINGING A COLD FRONT ACROSS THE REMAINDER OF SOUTHERN NEW ENGLAND AND THEN OFFSHORE. WINDS SHIFT TO WEST AND BECOME LIGHT. THE AIRMASS WILL STABILIZE AND FAVORABLE DYNAMICS WILL MOVE OFF. EVENING SHOWERS/THUNDERSTORMS WILL TAPER OFF AT NIGHT. SUFFICIENT AIRMASS DRYING IS INDICATED TO SUPPORT A CLEARING TREND OVERNIGHT. TUESDAY THROUGH FRIDAY... WITH THE UPPER TROUGH TO OUR WEST AND UPPER RIDGE TO OUR EAST...EXPECT THE UPPER FLOW TO REMAIN FROM THE SOUTHWEST. THE DEPARTED COLD FRONT WILL STALL OVER THE MARITIMES AND THE OFFSHORE WATERS. MEANWHILE COLD POOL INSTABILITY UNDER THE UPPER TROUGH WILL BE OVER NY AND ONTARIO WHILE NEW ENGLAND IS UNDER THE LEFT ENTRANCE REGION OF THE UPPER JET...A SUBSIDENT ZONE. SURFACE HIGH PRESSURE WILL BUILD OVER SOUTHERN NEW ENGLAND. THIS WILL MEAN A CHANCE OF SHOWERS WELL OFFSHORE AND OVER NY/ONTARIO WITH DRY WEATHER OVER SOUTHERN NEW ENGLAND. IF THE UPPER FEATURES SHIFT A LITTLE FURTHER EAST OR WEST...THEN IT IS POSSIBLE WE COULD HAVE A CHANCE OF SHOWERS IN PART OF SOUTHERN NEW ENGLAND. BUT DRY WEATHER IS THE LIKELY SCENARIO. SATURDAY... AS THE UPPER TROUGH LIFTS NORTH...EXPECT THE OFFSHORE FRONT TO SHIFT WEST CLOSER TO THE COAST. THIS SHOULD BRING AN INCREASE IN THE CHANCE OF SHOWERS...WITH THE BEST CHANCE ON THE CAPE AND ISLANDS. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 215 PM UPDATE... MODERATE CONFIDENCE THROUGH MON...THEN INCREASING CONFIDENCE MON NIGHT. THRU 00Z...SHOWERS AND SCATTERED TSTMS EXIT EASTERN MA 3PM OR 4PM...THEN ANY NEW CONVECTION SHOULD BE VERY ISOLATED IF AT ALL. ANY LINGERING MVFR ACROSS EASTERN MA WILL IMPROVE TO LOW END VFR BY 4 PM. TONIGHT...MARGINAL MVFR/VFR TO START THEN LOWERING TO MVFR/IFR AS THE NIGHT PROGRESS AS FOG DEVELOPS. ANOTHER ROUND OF HEAVY SHOWERS WITH SCT TSTMS DEVELOPS 07Z-10Z FROM SW TO NE. HEAVY RAIN AND GUSTY WINDS ARE THE MAIN THREATS. MONDAY...IFR/LIFR IN THE MORNING WITH SCT SHRA/TSTMS LIFTS NE INTO ME 12Z TO 15Z FROM SW TO NE. THEN LOW END VFR MOST TERMINALS BY AFTERNOON WITH ANOTHER ROUND OF TSTMS POSSIBLE EXPECT ACROSS RI AND SOUTHEAST MA WHERE RISK OF SHRA/TSTMS IS MUCH LOWER. A FEW STRONG STORMS ARE POSSIBLE WITH HEAVY RAIN AND GUSTY WINDS. MONDAY NIGHT...IMPROVING WEATHER AFTER 03Z OR SO AS COLD FRONT SWEEPS ACROSS THE AREA ALONG WITH A WIND SHIFT TO THE WNW. ANY LINGERING SHOWERS/TSTMS ACROSS NORTHERN MA AND SOUTHWEST NH AND MVFR CONDITIONS WILL IMPROVE TO VFR AFTER 03Z OR SO. KBOS TAF...MODERATE CONFIDENCE. SHOWERS/STORMS JUST ABOUT OFFSHORE AS OF 230 PM. LITTLE IF ANY NEW CONVECTION UNTIL 09Z-12Z MON. LOWERING TO MVFR/IFR TONIGHT IN FOG...THEN IMPROVING TO VFR MON MIDDAY. A FEW STRONG STORMS POSSIBLE MON AFTN. KBDL TAF...MODERATE CONFIDENCE. MVFR/VFR THEN LOWERING TO MVFR/IFR AFTER 07Z AS SHOWERS AND TSTMS OVERSPREAD THE TERMINAL. HEAVY RAIN AND GUSTY WINDS POSSIBLE. CONDITIONS IMPROVE TO VFR MON MIDDAY WITH ANOTHER ROUND OF AFTN T-STORM POSSIBLE. A FEW STRONG STORMS POSSIBLE. OUTLOOK...TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE. TUESDAY...VFR BUT WITH ISOLATED MVFR IN SHOWERS/TSTMS MAINLY SRN NEW HAMPSHIRE AND WESTERN/CENTRAL MASS IN THE AFTERNOON/EVENING. WEDNESDAY-THURSDAY...VFR.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE TODAY THROUGH MON. SCA REMAINS POSTED TODAY FOR ALL WATERS DUE TO INCREASING SW FLOW WITH GUSTS TO 25 KT...ESPECIALLY NEAR SHORE. THIS WILL ALSO PRODUCE BUILDING SEAS TO 5 FT ON OUTER WATERS. SHOWERS AND STORMS EXPECTED LATER THIS MORNING WITH ADDITIONAL STORMS POSSIBLE DURING AFTERNOON. SW WINDS DROP OFF A BIT TONIGHT AND MON BUT SEAS CONTINUE TO BUILD ON OUTER WATERS TO 6 OR 7 FT. SHOWERS/STORMS SHOULD BECOME MORE WIDESPREAD WITH AREAS OF FOG TONIGHT...BEFORE CONDITIONS GRADUALLY IMPROVE MON. OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...MODERATE CONFIDENCE. MONDAY NIGHT... COLD FRONT MOVES OVER THE WATERS. SOUTHWEST WINDS IN THE EVENING WILL GUST TO 25 KNOTS...BUT SHOULD DIMINISH AFTER THE COLD FRONT MOVES THROUGH AND WINDS SHIFT TO WEST. SEAS 5-7 FEET IN THE EVENING SHOULD SUBSIDE AFTER THE WIND SHIFT. TUESDAY...WINDS AND SEAS WILL CONTINUE TO SUBSIDE AS THE COLD FRONT SHIFTS EAST OF THE WATERS. SEAS AT 5 FEET MAY LINGER ON THE OUTER WATERS FOR PART OF THE DAY. WEDNESDAY-THURSDAY...LIGHTER WINDS AND SEAS AS HIGH PRESSURE BUILDS OVER THE WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230>234-236-237-251. SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ235-250- 254>256.
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&& $$ SYNOPSIS...WTB/JWD NEAR TERM...NOCERA SHORT TERM...JWD LONG TERM...WTB AVIATION...WTB/NOCERA MARINE...WTB/JWD

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