Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 031850 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 250 PM EDT SUN MAY 3 2015 .SYNOPSIS...
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CONDITIONS GRADUALLY WARM INTO MONDAY...WITH A CHANCE FOR A FEW SHOWERS THIS AFTERNOON. HIGH PRESSURE BUILDS OVER THE REGION DURING EARLY NEXT WEEK. A COLD FRONT SWEEPS SOUTH ACROSS THE REGION TUESDAY. HIGH PRESSURE REBUILDS WITH DRY AND WARMING WEATHER THE REMAINDER OF THE WORK WEEK.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... 145 PM UPDATE... SCATTERED SHOWERS HAVE FORMED IN WESTERN MA AND NORTHERN CT. OTHERS WERE MOVING SOUTH THROUGH SOUTHERN NH. INSTABILITY IS QUITE MARGINAL. A FEW OF THE STRONGER SHOWERS COULD ATTAIN SOME LIGHTNING LATER THIS AFTERNOON. BUT BY EVENING WITH SUNSET...THEY SHOULD BE RAPIDLY DIMINISHING. TEMPERATURES WERE ABOUT AS FORECAST WITH MID AND UPPER 70S IN THE FAR INTERIOR AND MUCH COOLER 50S AND 60S ADJACENT TO BAYS AND THE OCEAN. LOWERED TEMPERATURES IN BOSTON PROPER AS EASTERLY SEA BREEZES HAVE RESTRICTED TEMPERATURES TO NEAR 60 THUS FAR. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... TONIGHT... PRECIP WILL COME TO AN END FAIRLY RAPIDLY AS SUNSET APPROACHES. THE LOSS OF HEATING WILL DIMINISH ANY REMNANT INSTABILITY. HOWEVER...LEFTOVER HIGHER DWPTS AND CLOUDS WILL LEAD TO A WARMER NIGHT THAN PREVIOUS NIGHTS...MINS MAINLY IN THE UPPER 40S AND 50S. MON... PROBABLY THE WARMEST DAY WAVE EXPERIENCED THUS FAR. H85 TEMPS MAY EVEN EXCEED +10C...BUT ONCE AGAIN AFTERNOON MIXING SHOULD EXCEED THIS LEVEL. SW RETURN FLOW EXPECTED...SO WITH ANOTHER DOWNSLOPE COMPONENT...EXPECT MANY AREAS TO APPROACH OR EVEN EXCEED LOWER 80S THIS TIME AROUND...EVEN NEAR THE E COAST AS THE W COMPONENT MAY BE ENOUGH TO PROHIBIT SEA BREEZE DEVELOPMENT. HOWEVER THE S COMPONENT WILL KEEP SOUTHERN COAST REGION COOLER EVEN AWAY FROM THE COAST. GOOD MIXING SUGGESTS VERY DRY WEATHER AND A BUILDING PRES GRADIENT SUPPORTS WIND GUSTS APPROACHING 20-25 MPH...SEE THE FIRE WEATHER SECTION BELOW FOR CONCERNS. && .LONG TERM /TUESDAY THROUGH SUNDAY/...
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* ABOVE NORMAL TEMPERATURES EXPECTED THROUGHOUT THE WEEK * COLD FRONT MOVES THROUGH TUESDAY WITH SHOWERS POSSIBLE * POTENTIAL FOR A BACK DOOR COLD FRONT SATURDAY A DECENT BLOCKING SYSTEM IS SETTING UP ACROSS THE UNITED STATES THIS WEEK WITH A TROUGH ACROSS THE WESTERN STATES AND A STRONG RIDGE OVER MUCH OF THE EASTERN HALF OF THE COUNTRY. MODELS ARE IN AGREEMENT THROUGH MUCH OF THE LONG TERM ON THIS BLOCK PERSISTING. HOWEVER... TOWARDS THE END OF THE WEEK...THE GFS IS QUICK TO BREAK DOWN THE BLOCK...WHILE THE ECMWF SUSTAINS IT THROUGH THE WEEKEND. THIS RESULTS IN A COUPLE OF DIFFERENCES...LARGELY WITH THE INTRODUCTION OF A BACK DOOR COLD FRONT IN THE ECWMF FOR SATURDAY. LOOKS PICTURE PERFECT FOR MUCH OF THE LONG TERM. THE TWO POTENTIAL EXCEPTIONS TO THIS ARE A COLD FRONT MOVING THROUGH TUESDAY AND A POSSIBLE BACK DOOR COLD FRONT MOVING INTO THE REGION SATURDAY. OTHERWISE...TEMPERATURES LOOK TO BE WELL ABOVE NORMAL WITH HIGHS MOSTLY IN THE 70S AWAY FROM SHORE WITH A POSSIBILITY OF NEAR 80 ON FRIDAY. THE COLD FRONT TUESDAY WILL LIKELY BRING SOME SHOWERS. INSTABILITY LOOKS FAIRLY MARGINAL AT THIS POINT BUT CANNOT COMPLETELY RULE OUT THUNDER SO HAVE KEPT THE SLIGHT CHANCE OF THUNDER CARRIED BY THE PREVIOUS FORECAST. THE BACK DOOR COLD FRONT SATURDAY IS CONFINED TO THE ECMWF SOLUTION WITH NO SIGN OF IT IN THE GFS. SO SATURDAY IS A SOMEWHAT LOW CONFIDENCE FORECAST. IF THE ECMWF IS RIGHT...COOLER AND CLOUDIER WEATHER WITH SOME RAIN POSSIBLE. IF THE GFS VERIFIES...ONE MORE BEAUTIFUL SPRING DAY...BEFORE A POTENTIAL COLD FRONT. ALL THAT SAID...TYPICALLY THE ECMWF HANDLES THESE BLOCKING SCENARIOS A BIT BETTER THAN THE GFS SO WILL LEAN TOWARDS THE ECMWF AT THIS TIME.
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&& .AVIATION /19Z 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. THIS AFTERNOON...HIGH CONFIDENCE. VFR. SEA BREEZES AT BOTH COASTS CONTINUE THIS AFTERNOON...OTHERWISE MAINLY LIGHT SOUTHERLY FLOW. SCATTERED SHOWERS ESPECIALLY WESTERN AND CENTRAL PORTIONS OF THE FORECAST AREA. AN ISOLATED CLAP OF THUNDER CANNOT BE RULED OUT. BRIEF MVFR VSBY POSSIBLE IN ANY SHOWERS. TONIGHT INTO MONDAY...HIGH CONFIDENCE. VFR. WINDS BECOME MORE SW OVERNIGHT AND CONTINUE INTO MON...WHEN GUSTS AROUND 20 KT ARE POSSIBLE AT TIMES. KBOS TAF...HIGH CONFIDENCE IN TAF. LOW RISK OF A FEW AFTERNOON SHOWERS 19Z-23Z. SEA BREEZE CONTINUES THROUGH THE AFTERNOON. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...TUESDAY THROUGH FRIDAY... HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF BRIEF MVFR/IFR CONDITIONS IN SCT -SHRA/ISOLD -TSRA TUESDAY.
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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 MONDAY/... THROUGH TONIGHT...HIGH CONFIDENCE. MAINLY QUIET BOATING WEATHER EXPECTED WITH HIGH PRES SLIDING E OF THE WATERS. ONSHORE SEA BREEZES NEAR THE COAST THIS AFTERNOON OTHERWISE WINDS GENERALLY TURN FROM S TO SW THIS AFTERNOON AND OVERNIGHT. MONDAY...MODERATE CONFIDENCE. SW FLOW MAY APPROACH 25 KT NEAR THE SE COAST OF MA...BUT REMAIN 20 KT OR LESS ON THE OPEN OCEAN. THIS STEADY SW FLOW COULD ALSO ALLOW A BUILDING SWELL IN THE GULF OF MAINE TO EXCEED 5 FT...WHICH COULD IMPACT THE NE WATERS. NOT CONFIDENT ENOUGH ON THESE POTENTIAL SMALL CRAFT CONDITIONS TO SUPPORT AN ADVISORY AT THIS TIME...BUT IT MAY BE NEEDED. OUTLOOK...TUESDAY THROUGH FRIDAY...HIGH CONFIDENCE. TUESDAY...WINDS AND SEAS DIMINISH AS HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT CROSSING THE WATERS EARLY. WEDNESDAY THROUGH FRIDAY...QUIET BOATING WEATHER WITH HIGH PRESSURE OVER THE WATERS.
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&& .FIRE WEATHER... STILL WATCHING FIRE WEATHER CONDITIONS FOR MONDAY. MINIMUM AFTERNOON RELATIVE HUMIDITY VALUES DROPPING TO 20-30 PERCENT WITH AFTERNOON WIND GUSTS OF 20 TO PERHAPS 25 MPH. THEREFORE...MARGINALLY CLOSE TO RED FLAG CONDITIONS ON MONDAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...DOODY/RLG NEAR TERM...GAF SHORT TERM...DOODY LONG TERM...RLG AVIATION...DOODY/RLG/GAF MARINE...DOODY/RLG/GAF FIRE WEATHER...STAFF

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