Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 040911 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 411 AM EST WED MAR 4 2015 .SYNOPSIS...
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WEAK LOW PRESSURE WILL PUSH ALONG THE STALLED FRONT WITH ANOTHER ROUND OF SNOW TONIGHT INTO THURSDAY. HIGH PRESSURE WILL BUILD IN FOR FRIDAY THROUGH THIS WEEKEND...BRINGING DRY CONDITIONS WITH COLDER THAN NORMAL TEMPERATURES. A WEAKENING FRONT MAY BRING SOME LIGHT SNOW SHOWERS ON MONDAY.
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&& .NEAR TERM /UNTIL 6 AM THIS MORNING/... 225 AM UPDATE... BACK EDGE OF PRECIP AHEAD OF APPROACHING COLD FRONT HAS MOVED ACROSS N MA MAINLY N OF THE MASS PIKE AT 06Z. WHERE PRECIP IS LINGERING...MAINLY NEAR AND S OF THE MASS PIKE...IT IS MAINLY LIGHT RAIN. NOTING A COUPLE OF SPOTS WITH LINGERING MIXED PRECIP MAINLY ACROSS NE MA...BUT SHOULD END IN THE NEXT HOUR OR TWO. TEMPS AT 06Z MAINLY IN THE 30S...THOUGH A FEW SPOTS HAVE HIT 40 /41 AT KBID AND 40 AT KTAN/. VERY STRONG LOW LEVEL JET PASSING ACROSS SOUTHERN AND EASTERN AREAS AS SEEN ON 00Z KCHH AND KOKX SOUNDINGS AS WELL AS SHORT RANGE MODELS /SW WINDS AT 45-60 KT AT H925...UP TO 70 TO 80 KT AT H85/. SHOULD SEE THESE WINDS SLOWLY DIMINISH AND SHIFT TO W AS THE JET MOVES E WITH THE FRONTAL PASSAGE THIS MORNING. STRONG PRES FALLS CONTINUE AT 06Z... GENERALLY FROM 4-7 MB/3 HR WHICH HELPS TO MIX DOWN SOME OF THE SW WINDS ESPECIALLY ACROSS RI/SE MA AND THE HIGHER INLAND TERRAIN. SHORT RANGE MODELS /NAM AND HRRR/ SEEM TO BE HANDLING THE ENDING PRECIP EARLY THIS MORNING SO LEANED TOWARD THESE ALONG WITH RADAR TRENDS FOR THIS UPDATE. REMAINDER OF FORECAST IN PRETTY GOOD SHAPE BUT HAVE UPDATED TO BRING CONDITIONS CURRENT. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... COLD FRONT MOVES THROUGH SOUTHERN NEW ENGLAND DURING THE MORNING. THAT SHOULD END MOST OF THE PCPN. THE BEST CHANCE OF PCPN WOULD BE ALONG THE SOUTH COAST...WITH TEMPS WARM ENOUGH FOR RAIN. UPPER FLOW WILL BE WEST-TO-EAST AHEAD OF ANOTHER UPPER TROUGH SWINGING ACROSS THE GREAT LAKES. THE WEDNESDAY COLD FRONT WILL LINE UP WITH THAT UPPER FLOW...STALLING THE FRONT SOUTH OF NEW ENGLAND. MEANWHILE THE UPPER JET IN THE FLOW MOVES ACROSS NEW ENGLAND AND PLACES US IN ITS RIGHT ENTRANCE REGION. THIS WILL GENERATE SUPPORT FOR A WAVE ON THE FRONT PUSHING PCPN NORTH AGAIN WEDNESDAY NIGHT. AT THE SAME TIME...WINDS SHIFTING TO NORTH WILL DRAW COLDER AIR SOUTH ACROSS THE REGION AGAIN. SO ANY DEVELOPING PCPN WOULD CHANGE TO FREEZING RAIN AND THEN SNOW. QUESTION REMAINS AS TO WHETHER THE COLD AIR WILL BE DRY ENOUGH TO SUPPRESS THE PCPN SHIELD FARTHER SOUTH. THIS MAY LIMIT ANY SIGNIFICANT PCPN TO THE SOUTH COAST OR EVEN JUST OFFSHORE. WE WILL GO WITH CATEGORICAL POPS ALONG THE SOUTH COAST...LIKELY POPS ACROSS CT-RI-SE MASS...AND CHANCE POPS FARTHER NORTH. BASED QPF ON HPC VALUES. DUE TO THE COMBINATION OF EXPECTED PCPN AND EXPECTED TEMPS...WE HAVE ISSUED A WINTER STORM WATCH ALONG THE SOUTH COAST INCLUDING CAPE COD AND ALL THE ISLANDS. THIS WILL ALSO INCLUDE KENT COUNTY RI. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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* HIGH PRESSURE BUILDS IN THU NIGHT...PASSING S FRIDAY * MOISTURE STARVED COLD FRONT MOVES THROUGH THIS WEEKEND * UNCERTAIN FORECAST EARLY NEXT WEEK MODELS ARE IN FAIRLY GOOD AGREEMENT GOING INTO THE WEEKEND. THERE ARE SOME MINOR DISCREPANCIES IN TIMING OF A COLD FRONT THROUGH THE WEEKEND. THEN NEXT WEEK THEY DIVERGE A BIT...WITH ECMWF ATTEMPTING TO BRING A COASTAL LOW UP OVER THE BENCHMARK TUESDAY AND THE GFS BRINGING IN A STRONG HIGH PRESSURE JUST SOUTH OF SOUTHERN NEW ENGLAND. AT THIS POINT...WILL OPT FOR A BLEND OF AVAILABLE GUIDANCE FOR THE WEEKEND INTO EARLY NEXT WEEK TO TAKE CARE OF SOME OF THE TIMING ERRORS. HIGH PRESSURE BUILDS IN FROM THE MIDWEST THURSDAY NIGHT...BRINGING AN END TO THE SNOW. THEN FRIDAY...THE HIGH PRESSURE BECOMES SUPPRESSED TO THE SOUTH AS LOW PRESSURE MOVES INTO QUEBEC. THIS WILL KEEP CHILLY TEMPERATURES...WELL BELOW NORMAL FOR EARLY MARCH... IN PLACE FOR SOUTHERN NEW ENGLAND. THIS WEEKEND...A SHORTWAVE PUSHES LOW PRESSURE THROUGH QUEBEC... ALLOWING A COLD FRONT TO MOVE THROUGH SOUTHERN NEW ENGLAND. AT THIS POINT...THIS FRONTAL PASSAGE APPEARS TO BE FAIRLY MOISTURE STARVED SO LITTLE IF ANY PRECIP WILL ACCOMPANY THIS FRONT. TEMPERATURES MODERATE A BIT BUT REMAIN WELL BELOW NORMAL. EARLY NEXT WEEK MODELS DIVERGE WITH RADICALLY DIFFERENT SOLUTIONS FOR SOUTHERN NEW ENGLAND. GIVEN THE TIME FRAME...THIS IS NOT COMPLETELY UNUSUAL...SO WILL TAKE EITHER MODEL WITH A GRAIN OF SALT AT THIS TIME. REGARDLESS OF THE MODEL...IT DOES LOOK LIKE TEMPERATURES CONTINUE TO MODERATE INTO NEXT WEEK.
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&& .AVIATION /09Z 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 TONIGHT/... THROUGH 12Z...CIGS MAINLY IFR-LIFR WITH VLIFR ALONG THE S COAST. PRECIP ENDING MAINLY ACROSS THE CT VALLEY AND N OF THE MASS PIKE WITH VFR VSBYS...BUT PATCHY FOG DEVELOPING WITH VSBYS RANGING FROM MVFR TO IFR WITH PATCHY LIFR. S-SW WINDS AT 15-20 KT GUSTING TO 25 KT MAINLY ACROSS E MA/RI WHERE STRONG LOW LEVEL JET LINGERS. LLWS LIKELY AT 2KFT THERE. LIGHT RAIN LINGERS MAINLY S OF THE MASS PIKE. TODAY...MODERATE CONFIDENCE. N OF MASS PIKE...SHOULD SEE GENERALLY VFR CONDITIONS. S OF MASS PIKE...VFR WITH PATCHY MVFR CIGS/VSBYS ALONG S COASTAL AREAS WITH LINGERING LIGHT RAIN. TONIGHT...MODERATE CONFIDENCE. N OF MASS PIKE...MAINLY VFR CIGS THOUGH MAY LOWER TO MVFR ALONG THE PIKE AFTER MIDNIGHT. S OF THE MASS PIKE...CONDITIONS DETERIORATE TO MVFR BY 05Z IN MIXED PRECIP CHANGING OVER TO SNOW FROM N-S. WILL VSBYS LOWER TO IFR-LIFR ACROSS N CT/RI/SE MA IN PERIODS OF SN/+SN AFTER 05Z. KBOS TAF...HIGH CONFIDENCE IN OVERALL TRENDS...LOWER CONFIDENCE IN EXACT TIMING. KBDL TAF...HIGH CONFIDENCE IN OVERALL TRENDS...LOWER CONFIDENCE IN EXACT TIMING. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... MODERATE CONFIDENCE. MAINLY VFR THROUGH THIS PERIOD. BRIEF MVFR CONDITIONS ARE POSSIBLE THURSDAY NIGHT AS SNOW COMES TO AN END.
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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 WEDNESDAY/... OVERNIGHT... S-SW WINDS CONTINUE TO INCREASE AS PRES GRADIENT TIGHTENS...WHICH WILL CONTINUE TO SUPPORT WINDS GUSTING TO 25-30 KT AT TIMES. SEAS ALSO BUILDING...AND WILL INCREASE TO 6-8 FT ON THE OUTER WATERS. SMALL CRAFT ADVISORY CONTINUES FOR ALL WATERS. WEDNESDAY... COLD FRONT CROSSES THE WATERS. THIS WILL SHIFT THE WIND OUT OF THE WEST. WINDS WILL CONTINUE TO GUST AT TIMES TO 25 KNOTS...AND SEAS WILL CONTINUE AT 5 TO 8 FEET ON THE EXPOSED WATERS. SMALL CRAFT ADVISORY CONTINUES BUT MAY BE DROPPED ON SOME NEAR SHORE WATERS. WEDNESDAY NIGHT... WINDS BECOME NORTHWEST AND PULL COLDER AIR ACROSS THE WATERS...GUSTING 20-25 KNOTS LATER AT NIGHT. SEAS WILL LINGER AROUND 5-6 FEET OVERNIGHT. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... HIGH CONFIDENCE. WINDS AND SEAS SLOWLY DIMINISH THURSDAY NIGHT AND FRIDAY AS HIGH PRESSURE BUILDS OVER THE WATERS. THEY THEN INCREASE BUT ONLY MODESTLY OVER THE WEEKEND AS A COLD FRONT APPROACHES THEN CROSSES THE WATERS. SMALL CRAFT ADVISORIES WILL LIKELY BE NECESSARY ON THE OUTER WATERS FOR A PORTION OF THIS TIME.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY EVENING FOR MAZ020>024. RI...WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY EVENING FOR RIZ003>008. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ230-236. SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ235-237- 250-254>256. SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ251.
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&& $$ SYNOPSIS...WTB/RLG NEAR TERM...EVT SHORT TERM...WTB LONG TERM...RLG AVIATION...RLG/EVT MARINE...WTB/RLG/EVT

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