Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 072045 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 445 PM EDT MON JUL 7 2014 .SYNOPSIS...
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VERY WARM/HOT AND HUMID WEATHER WILL PERSIST THROUGH MID WEEK. WHILE MUCH OF THE TIME WILL BE DRY...A FEW STRONG HIT AND MISS THUNDERSTORMS WILL BE POSSIBLE AT TIMES ESPECIALLY ACROSS THE INTERIOR. A FEW ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE DURING THURSDAY IF THE COLD FRONT MOVES SLOWER. DRY WEATHER WITH LOWER HUMIDITY WILL ARRIVE BY THE END OF THE WEEK INTO THE WEEKEND.
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&& .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ***SCATTERED STRONG TO SEVERE THUNDERSTORMS THIS EVENING ACROSS PORTIONS OF INTERIOR SOUTHERN NEW ENGLAND*** SHORTWAVE COMBINING WITH MODEST INSTABILITY ALONG WITH 30 TO 40 KNOTS OF SHEAR HAS ALLOWED SCATTERED STRONG TO SEVERE THUNDERSTORMS TO WORK INTO SOUTHWEST NH/NORTHWEST LATE THIS AFTERNOON. GIVEN CAPES ON THE ORDER OF 1000 TO 1500 J/KG INTO THIS EVENING...FEEL THE THREAT FOR SCATTERED STRONG TO SEVERE THUNDERSTORMS MAY EXPAND TO AFFECT PORTIONS OF NORTHERN CT...WESTERN/NORTH CENTRAL MA AND INTO SOUTHERN NH INTO THE EVENING HOURS. THE PRIMARY THREAT WILL BE STRONG TO DAMAGING STRAIGHT LINE WIND GUSTS ALONG WITH TORRENTIAL RAINFALL. HAIL WILL BE A SECONDARY CONCERN IF ANY DISCRETE CORES CAN DEVELOP. THERE IS UNCERTAINTY IF THIS ACTIVITY WILL HOLD TOGETHER AS IT TRIES TO ENTER EASTERN MA/RHODE ISLAND. WE SHOULD SEE A WEAKENING TREND...BUT STILL AT LEAST SOME CONVECTIVE POTENTIAL GIVEN 30+ KNOTS OF SHEAR ALONG WITH SOME INSTABILITY. WILL HAVE TO MONITOR THIS CLOSELY THIS EVENING. SHOULD SEE THE ACTIVITY WIND DOWN NEAR OR SHORTLY AFTER MIDNIGHT AS THE SHORTWAVE DEPARTS. OTHERWISE...CAN/T RULE OUT A SPOT SHOWER OR THUNDERSTORM GIVEN LOW LEVEL JET AND LEFT OVER INSTABILITY...BUT THE VAST MAJORITY OF THE NIGHT SHOULD BE DRY. LOW TEMPS WILL ONLY FALL BACK TO THE LOWER 70S IN MOST LOCALES...WITH PERHAPS A FEW UPPER 60S IN NORTHWEST MA/SOUTHWEST NH. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... TUESDAY AND TUESDAY NIGHT... ANOTHER VERY WARM/HOT AND HUMID DAY ACROSS THE REGION. HIGHS SHOULD TOP OUT AROUND 90 TO THE LOWER 90S IN MANY LOCATIONS...ALTHOUGH A FEW DEGREES COOLER ON THE SOUTH COAST/CAPE ISLANDS WITH SOUTHWEST WINDS. IT WILL ONCE AGAIN BE BREEZY IN THE AFTERNOON WITH SOUTHWEST WIND GUSTS OF 20 TO 30 MPH. WHILE MUCH OF THE DAY WILL BE DRY...THE ATMOSPHERE WILL BECOME MODERATELY UNSTABLE DURING THE AFTERNOON. EXPECT 1000 TO 2000 J/KG OF CAPE TO DEVELOP ALONG WITH 30 TO 40 KNOTS OF SHEAR. THE MAIN UNCERTAINTY IS THAT WE DON/T HAVE AS STRONG A SHORTWAVE APPROACHING AS THE ONE THIS AFTERNOON/EVENING. HOWEVER...GIVEN VERY GOOD INSTABILITY/SHEAR WE PROBABLY WILL SEE ISOLATED TO SCATTERED THUNDERSTORMS DEVELOP DURING THE LATE AFTERNOON/EVENING HOURS. WHILE AREAL COVERAGE REMAINS UNCERTAIN AND COULD BE LIMITED...ANY STORM OR STORM/S THAT ARE ABLE TO DEVELOP IN THIS ENVIRONMENT COULD BECOME STRONG TO SEVERE. THE MAIN THREAT WOULD BE STRONG TO DAMAGING STRAIGHT LINE WIND GUSTS...BUT LARGE HAIL CAN/T BE RULED OUT WITH ANY DISCRETE CELLS. HEAVY RAINFALL AND DANGEROUS CLOUD TO GROUND LIGHTNING WILL BE THE MAIN THREATS WITH THIS ACTIVITY. BEST SHOT FOR A FEW STRONG TO SEVERE THUNDERSTORMS WILL BE NORTHWEST OF A BOSTON TO PROVIDENCE LINE...ALTHOUGH CAN/T REALLY RULE ONE OUT ANYWHERE. SHOULD SEE ACTIVITY WIND DOWN AFTER MIDNIGHT...BUT CAN/T RULE OUT A FEW SPOT SHOWERS/THUNDERSTORMS RIGHT THROUGH DAYBREAK WEDNESDAY GIVEN GOOD JET DYNAMICS/INSTABILITY. && .LONG TERM /WEDNESDAY THROUGH MONDAY/...
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HIGHLIGHTS... * VERY WARM/HOT AND HUMID ON WED * A FEW THUNDERSTORMS POSSIBLE WED INTO THU * DRIER AND LESS HUMID AIR RETURNS BY THE END OF THE WEEK OVERVIEW AND MODEL PREFERENCES... MEDIUM RANGE MODEL SUITE ARE IN GOOD AGREEMENT IN CONTINUING TO DIG A LONG WAVE UPPER TROUGH/CUTOFF LOW FROM HUDSON BAY THROUGH THE GREAT LAKES TO THE OHIO VALLEY WHILE RIDGING BUILDS ACROSS WESTERN CANADA INTO THE NORTHERN ROCKIES INTO THURSDAY. WITH THE TROUGH AXIS CUTTING THROUGH THE LAKES...WILL SEE SLOW PROGRESSION OF COLD FRONT TRYING TO SLICE THROUGH THE REGION. ONCE THIS TROUGH LIFTS NE LATER THU/THU NIGHT...CONDITIONS LOOK TO IMPROVE WITH DRIER AIR MOVING IN. TIMING OF NEXT SYSTEM WORKING ACROSS THE NORTHERN TIER STATES IS IN QUESTION WITH LACK OF MODEL CONTINUITY...THOUGH LOOKS LIKE ANOTHER H5 CUTOFF LOW DIGS OUT OF NORTHERN CANADA ACROSS HUDSON BAY INTO EARLY NEXT WEEK...SO ANOTHER TROUGH MAY START TO DIG SERD. MODELS ARE DIVIDED ON HOW FAR THIS WILL DIG S AND HOW SURFACE SYSTEMS RIDING ALONG IN THIS FLOW WILL MOVE...SO LOWER CONFIDENCE IN FORECAST BEYOND SATURDAY. WITH THE GOOD AGREEMENT WITH THE MODELS EARLY IN THIS CYCLE...USED A BLEND OF AVAILABLE GUIDANCE THEN LEANED TOWARD THE ENSEMBLES BEYOND FRIDAY WITH THE TIMING ISSUES NOTED. DETAILS... WEDNESDAY/WEDNESDAY NIGHT... WITH THE COLD FRONT RUNNING NEARLY PARALLEL TO THE UPPER LEVEL TROUGH...WILL BE SLOW TO EXIT THE REGION. STILL QUITE A BIT OF INSTABILITY ACROSS THE REGION WITH CAPES IN THE 500-1000 J/KG RANGE AND LIFTED INDICES BELOW ZERO. SO...KEPT CHANCE OF SHOWERS/TSTMS GOING IN THE FORECAST. ALSO...PWATS ARE 1.8 TO 1.9 INCHES...SO WILL SEE HEAVY RAINERS WITH ANY TSTMS. KEPT HEAVY RAINFALL WORDING GOING IN THE FORECAST INTO EARLY WED NIGHT. WILL ALSO NEED TO MONITOR WIND SHEAR ON ORDER OF AROUND 40 KT WHICH COULD HELP VENT ANY CONVECTION ALONG WITH THE CAPES AND LI/S. EXPECTING WARM AND HUMID CONDITIONS WITH HIGHS IN THE 80S...HIGHEST ACROSS E MA/RI/N CT. FOR NOW...LOOKS LIKE THE FRONT WILL CLEAR THE COAST OVERNIGHT WED BUT MAY HUG THE COAST INTO THU MORNING. BRINGING BACK EDGE OF PRECIP SLOWLY SEWD AND HAVE KEPT MENTION OF THUNDER IN GENERALLY ACROSS AREAS S OF THE MASS PIKE. THURSDAY... HAVE KEPT SLIGHT CHANCE MENTION OF SHOWERS/TSTMS...MAINLY ACROSS E MA/RI/NE CT THU MORNING...THEN SHOULD SHIFT OFFSHORE DURING THE AFTERNOON. THIS WILL BE DEPENDENT UPON TIMING OF THE UPPER TROUGH TO THE N AND W. MODELS DO SHOW PRETTY GOOD AGREEMENT THOUGH. WILL STILL NEED TO MONITOR THE TIMING AND WHETHER MORE INSTABILITY THAN CURRENTLY INDICATED WILL HANG BACK. DEWPTS IN THE LOWER-MID 60S DO HANG BACK ACROSS THE AREA...SO MAY HAVE SOME PROBLEMS EARLY. FRIDAY AND SATURDAY... HIGH PRES WILL PUSH E FROM THE GREAT LAKES...BRINGING COOLER AND DRIER CONDITIONS. SEA BREEZES WILL BE LIKELY BOTH DAYS WITH THE LIGHT WIND FLOW IN PLACE THANKS TO THE HIGH. DAYTIME HIGHS WILL BE IN THE LOWER 80S...CLOSE TO SEASONAL NORMALS. CLOUDS LOOK TO INCREASE FROM THE W SATURDAY NIGHT. SUNDAY AND MONDAY... AS LONG WAVE TROUGHING LOOKS TO RETURN TO THE W OF THE REGION... MAY SEE ANOTHER FRONT BEGIN TO APPROACH. HOWEVER...DUE TO TIMING ISSUES...NOT A LOT OF CONFIDENCE BUT DOES LOOK LIKE ANOTHER ROUND OF SCT SHOWERS/TSTMS RETURN.
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&& .AVIATION /21Z MONDAY THROUGH SATURDAY/...
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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 TUESDAY NIGHT/... THIS AFTERNOON AND TONIGHT...MODERATE CONFIDENCE. SCT SHOWERS/THUNDERSTORMS ARE EXPECTED TO MOVE INTO INTERIOR SOUTHERN NEW ENGLAND ROUGHLY BETWEEN 4 PM AND MIDNIGHT. A FEW OF THE STORMS MAY RESULT IN STRONG WIND GUSTS AND BRIEF TORRENTIAL RAIN. THE ACTIVITY WILL BE HIT AND MISS...BUT WILL RESULT IN LOCALIZED MVFR-IFR CONDITIONS. ACTIVITY SHOULD WEAKEN AS IT MOVES INTO EASTERN MA/RI...BUT A FEW THUNDERSTORMS CAN/T BE RULED OUT AFTER 8 OR 9 PM THROUGH ABOUT MIDNIGHT. SOUTHWEST WIND GUSTS OF 25 TO 30 KNOTS SHOULD DIMINISH SOME AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING. OTHERWISE...VFR CONDITIONS DOMINATE THROUGH TONIGHT OTHER THAN SOME LOCALIZED PATCHY GROUND FOG LATE. LOW PROBABILITY THAT LOW CLOUDS/FOG DEVELOP ACROSS SOUTHEAST NEW ENGLAND BUT DIDN/T HAVE ENOUGH CONFIDENCE TO INSERT INTO THE TAF. LATER SHIFTS WILL HAVE TO MONITOR. TUESDAY AND TUESDAY NIGHT...MODERATE CONFIDENCE. VFR CONDITIONS WILL DOMINATE...BUT PERHAPS A BETTER CHANCE OF LOW CLOUDS AND FOG DEVELOPING ALONG THE SOUTHEAST NEW ENGLAND COAST TUE NIGHT. IN ADDITION...A FEW AFTERNOON AND EVENING STRONG THUNDERSTORMS ARE POSSIBLE WITH THE BEST SHOT NORTHWEST OF A BOS TO PVD LINE. KBOS TAF...MODERATE CONFIDENCE IN TAF. LOW PROBABILITY FOR A THUNDERSTORM IN THE VICINITY BETWEEN 00Z AND 04Z. KBDL TAF...MODERATE CONFIDENCE IN TAF. LOW TO MODERATE PROBABILITY FOR A FEW STRONG THUNDERSTORMS IN THE VICINITY BETWEEN 21Z AND 03Z. OUTLOOK...WEDNESDAY THROUGH SATURDAY... WEDNESDAY...MODERATE CONFIDENCE. MAINLY VFR AWAY FROM THE COAST. AREAS OF IFR CIGS/VSBYS ACROSS COASTAL AREAS IN LOW CLOUDS/FOG WHICH SHOULD IMPROVE BY AROUND MID MORNING...BUT WILL REDEVELOP AFTER MIDNIGHT WED NIGHT. WILL SEE LOCAL BRIEF MVFR-IFR CIGS/VSBYS IN SCT SHOWERS/TSTMS. THURSDAY...MODERATE CONFIDENCE. SHOULD BE MAINLY VFR. WIDELY SCT SHOWERS LINGER WITH LOCAL MVFR VSBYS. ISOLD THUNDER POSSIBLE ALONG S COAST. FRIDAY...HIGH CONFIDENCE. VFR CONDITIONS. SATURDAY...MODERATE CONFIDENCE. VFR INTO EARLY SATURDAY NIGHT. MAY SEE MVFR CIGS/VSBYS AFTER MIDNIGHT IN SCT SHOWERS/ISOLD TSTMS ACROSS WESTERN AREAS AS ANOTHER SYSTEM APPROACHES. LOWER CONFIDENCE DUE TO TIMING ISSUES.
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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 /THROUGH TUESDAY NIGHT/...HIGH CONFIDENCE. PERSISTENT SOUTHWEST FLOW WILL CONTINUE RIGHT THROUGH TUESDAY NIGHT AHEAD OF A SLOW MOVING COLD FRONT. NEAR SHORE GUSTS OF 25 TO 30 KNOTS WILL DIMINISH AFTER SUNSET...SO WILL BE ABLE TO LET SOME OF THE NEAR SHORE HEADLINES EXPIRE. WINDS MAY BE A TOUCH LESS GUSTY ON TUESDAY...BUT STILL THE RISK FOR 25 KNOT WIND GUSTS SO MORE NEAR SHORE SCA HEADLINES MAY BE NEEDED. AS FOR THE OUTER-WATERS...WILL CONTINUE TO NEED SCA HEADLINES WITH LONG SOUTHWEST FETCH RESULTING IN 4 TO 7 FOOT SEAS. OTHERWISE...MAY SEE AREAS OF FOG DEVELOP MAINLY TUE NIGHT WHICH COULD BE LOCALLY DENSE ACROSS THE SOUTHERN WATERS. IN ADDITION...LOW TO MODERATE PROBABILITY FOR A FEW STRONG THUNDERSTORMS TO MOVE ACROSS THE NEAR SHORE WATERS THIS EVENING AND AGAIN LATE TUE. OUTLOOK...WEDNESDAY THROUGH SATURDAY. WEDNESDAY...MODERATE CONFIDENCE. S-SW WINDS CONTINUE AT 10-15 KT. A FEW GUSTS TO 20 KT POSSIBLE THROUGH THE DAYLIGHT HOURS. S SWELLS WILL CONTINUE AT 5-7 FT ON THE OUTER WATERS. REDUCED VSBYS IN FOG WILL CONTINUE. SCT SHOWERS/TSTMS WITH HEAVY RAINFALL THROUGH WED EVENING. THURSDAY...MODERATE CONFIDENCE. S-SW WINDS BELOW 15 KT DURING THE DAY WILL SLOWLY SHIFT TO W-NW THURSDAY NIGHT. MAY SEE 5 FOOT SEAS ACROSS THE SOUTHERN OUTER WATERS EARLY...THEN SHOULD SUBSIDE. FRIDAY-SATURDAY...HIGH CONFIDENCE. WINDS AND SEAS BELOW SMALL CRAFT CRITERIA.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230- 236-251. SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR ANZ235-237- 254>256. SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ250. && $$ SYNOPSIS...FRANK/EVT NEAR TERM...FRANK SHORT TERM...FRANK LONG TERM...EVT AVIATION...FRANK/EVT MARINE...FRANK/EVT

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