Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 260716 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 316 AM EDT WED AUG 26 2015 .SYNOPSIS...
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A COLD FRONT WILL LINGER NEAR THE COAST TODAY BEFORE FINALLY PUSHING OFFSHORE TONIGHT. HIGH PRESSURE SLOWLY BUILDS INTO THE REGION THROUGH THE END OF THE WEEK WITH DRY AND SEASONABLE WEATHER AND COMFORTABLE HUMIDITY LEVELS. THE HIGH MOVES OFFSHORE THIS WEEKEND WITH WARMER TEMPERATURES...THEN HEAT AND HUMIDITY MAY RETURN FOR NEXT WEEK.
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&& .NEAR TERM /THROUGH TODAY/...
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SHOWERS AND ISOLD TSTMS WILL BE EXITING THE CAPE/ISLANDS...BUT STILL HAVE TO WATCH AREA OF CONVECTION LIFTING NE FROM THE OCEAN. WE STILL HAVE 1500 J/KG OF SBCAPE OVER THE OCEAN AND MODELS MAINTAIN UP TO 1000 J/KG ACROSS SE MA THROUGH THE MORNING WITH BACK EDGE OF DEEPER MOISTURE AND HIGHER KI AXIS LINGERING OVER THE CAPE/ISLANDS AND E COASTAL MA THROUGH 12-15Z BEFORE DRIER AIR PUSHES EAST. SO THE THREAT OF SHOWERS AND PERHAPS A TSTM WILL CONTINUE OVER THE CAPE/ISLANDS THIS MORNING AND POSSIBLY INTO E MA WHERE COLD FRONT WILL STALL TODAY. WILL HAVE LOW POPS THIS MORNING ...OTHERWISE DRY TODAY WITH MOSUNNY SKIES WEST AND INCREASING SUNSHINE EAST. UPPER LEVEL TROF AXIS WILL BE ACROSS THE EASTERN GT LAKES TODAY WITH FRONT STALLING NEAR E COASTAL MA AND CAPE COD. THIS WILL SLOW THE INFLUX OF DRIER AIR INTO SE NEW ENG WITH HUMID CONDITIONS THIS MORNING BEFORE DEWPOINTS SLOWLY DROP THIS AFTERNOON. HOWEVER...COMFORTABLE HUMIDITY IN W NEW ENG WITH DEWPOINTS IN THE 50S. 850 MB TEMPS 12-15C FROM WEST TO EAST SUPPORT HIGHS IN THE LOW TO MID 80S...WARMEST E NEW ENG WITH UPPER 70S INTERIOR HIGH TERRAIN.
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&& .SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/...
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TONIGHT... COLD FRONT PUSHES OFFSHORE WITH DRY CONDITIONS AND MOCLEAR SKIES. PATCHY INTERIOR VALLEY FOG POSSIBLE LATE AT NIGHT. DECENT RADIATIONAL COOLING WILL ALLOW LOW TEMPS TO DROP INTO THE 50S...EXCEPT LOW TO MID 60S BOS/PVD URBAN CENTERS AND CAPE/ACK. THURSDAY... MID LEVEL TROF AXIS SWINGS ACROSS NEW ENG BUT THE COLUMN IS DRY AS HIGH PRES BUILDS IN FROM THE WEST. THIS WILL LEAD TO MOSUNNY SKIES AND VERY PLEASANT CONDITIONS WITH COMFORTABLE HUMIDITY LEVELS. 850 MB TEMPS 10-11C SUPPORT MAXES MID 70S HIGHER TERRAIN TO NEAR 80 DEGREES COASTAL PLAIN AND INTERIOR VALLEYS.
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&& .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... OVERVIEW... MEDIUM RANGE MODELS AND ENSEMBLES REMAIN IN VERY GOOD AGREEMENT DURING THE THU-SAT TIMEFRAME...WEAKENING THE EASTERN LONG WAVE TROUGHING AS CUTOFF LOW LIFTS NE OVER EASTERN CANADA. UPPER FLOW BECOMES MORE ZONAL ACROSS THE EASTERN SEABOARD BY LATE THIS WEEK. LARGE SURFACE HIGH PRESSURE WILL BE THE DOMINANT FEATURE ACROSS THE EASTERN HALF OF THE U.S. INTO THIS WEEKEND. DO NOTE DIVERGENCE IN SOME OF THE MODEL SOLUTIONS DURING THIS WEEKEND...NAMELY THE 06Z/12Z GFS...IN HANDLING LINGERING H5 SHORT WAVE WEAKNESS. MOST MODELS AND ENSEMBLES KEEP THIS HANGING AROUND THE GREAT LAKES INTO OHIO VALLEY...BUT THE GFS SHIFTS IT E MUCH FASTER AND OVERDOES THE PRECIP FIELD. ON SATURDAY...IT TRIES TO WORK MOISTURE UP THE EASTERN SEABOARD AROUND THE SUBTROPICAL RIDGE OFFSHORE...THEN SHIFTS SHORT WAVE ENERGY E AROUND THE SUNDAY/SUNDAY NIGHT TIMEFRAME. THE 00Z ECMWF/GGEM KEEP THIS WEAKNESS WELL W OF THE REGION AND NOT NEARLY AS MUCH CONVECTION WITH IT AS THE HIGH PRES OFFSHORE REMAINS IN CONTROL. GEFS/ECENS MEANS ALSO KEEP A MAINLY DRY FORECAST GOING...SO LEANED TOWARD THE DRIER SOLUTION DURING THIS TIMEFRAME. INTO EARLY NEXT WEEK...LOOKS LIKE HIGH PRES RETURNS AS W-NW FLOW ALOFT TAKES OVER WITH HIGH AMPLITUDE UPPER RIDGE BUILDING INTO HUDSON AND JAMES BAYS. SW SURFACE WINDS TAKE OVER...WHICH BRING WARMER TEMPS AND HIGHER HUMIDITY. LEANED TOWARD AVAILABLE GUIDANCE FOR THE EARLY PORTION OF THIS FORECAST...THEN TRANSITIONED TOWARD THE ENSEMBLE MEANS FROM SUNDAY ONWARD. DETAILS... THURSDAY THROUGH SATURDAY...HIGH CONFIDENCE. LARGE HIGH PRES RIDGE BUILDS E OUT OF THE MIDWEST/GREAT LAKES. EXPECT DRY CONDITIONS. A GENERAL W-NW FLOW IN PLACE FOR THURSDAY-FRIDAY...THEN RIDGE AXIS SHIFTS E ON SATURDAY BRINGING RETURN TO SW WINDS AND GRADUALLY INCREASING HUMIDITY. SUNDAY...LOW CONFIDENCE. AS MENTIONED ABOVE...MODEL SOLUTION DIVERGENCE DUE TO TIMING OF SYNOPTIC FEATURES ACROSS THE REGION. LEANED TOWARD THE HPC GUIDANCE FOR THIS PERIOD. KEPT A DRY FORECAST GOING. WILL ALSO SEE TEMPS RISE...WITH HIGHS POSSIBLY AS MUCH AS 5 TO 10 DEGREES ABOVE NORMAL. MONDAY AND TUESDAY...LOW TO MODERATE CONFIDENCE. UPPER LEVEL RIDGE BUILDS ACROSS THE CENTRAL U.S. INTO CENTRAL CANADA...KEEPING MAINLY DRY FLOW IN PLACE. SOME UNCERTAINTY DUE TO DIVERGENCE WITH EARLIER SOLUTIONS...THOUGH LOOKING A BIT MORE CONFIDENT. TEMPERATURES WILL CONTINUE TO TREND ABOVE NORMAL DURING THIS TIMEFRAME...WHICH IS BACK TO SCHOOL FOR SOME. BOTH MODELS AND ENSEMBLES ARE HINTING AT UPPER 80S TO AROUND 90 AS UPPER LEVEL RIDGE CONTINUES TO BUILD ACROSS THE CENTRAL U.S. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
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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 THURSDAY/... THROUGH 12Z...PATCHY FOG AND STRATUS OVERNIGHT WITH MVFR AND SOME IFR. SHOWERS AND TSTMS EXITING CAPE/ISLANDS NEXT 1-2 HOURS...BUT CONTINUED THREAT OF A FEW SHOWERS OR A TSTM THROUGH 12Z SE MA AND CAPE. TODAY...HIGH CONFIDENCE. AREAS OF MVFR/IFR STRATUS AND PATCHY FOG EARLY...OTHERWISE VFR. BRIEF SHOWER OR TSTM POSSIBLE THIS MORNING SE COASTAL MA AND CAPE COD. COASTAL SEABREEZES DEVELOPING. TONIGHT AND THURSDAY...HIGH CONFIDENCE. VFR. PATCHY IFR FOG LATE TONIGHT INTERIOR VALLEYS. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. A PERIOD OF MVFR CIGS POSSIBLE EARLY THIS MORNING. SEABREEZE LIKELY BY MIDDAY. ANOTHER SEABREEZE POSSIBLE THU BUT LOWER CONFIDENCE. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...MODERATE TO HIGH CONFIDENCE. THURSDAY NIGHT THROUGH SUNDAY...MAINLY VFR CONDITIONS. COULD SEE WEAK SEA BREEZES ALONG THE COASTLINES. MAY SEE BRIEF PATCHY FOG OVERNIGHT THU NIGHT ACROSS NORMALLY PRONE INTERIOR VALLEYS.
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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 THURSDAY/...HIGH CONFIDENCE. QUIET BOATING WEATHER WITH WINDS AND SEAS BELOW SCA THRESHOLDS THROUGH THE PERIOD. A FEW SHOWERS OR PERHAPS A TSTM POSSIBLE THIS MORNING OVER E WATERS...OTHERWISE DRY WEATHER. OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...HIGH CONFIDENCE. EXPECT WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT CRITERIA AS HIGH PRESSURE TAKES CONTROL. EXPECT W-NW WINDS THU-FRI...SHIFTING TO S-SW FRI NIGHT-SUNDAY.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC NEAR TERM...KJC SHORT TERM...KJC LONG TERM...EVT AVIATION...KJC/EVT MARINE...KJC/EVT

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