Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 162258 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 658 PM EDT THU APR 16 2015 .SYNOPSIS... A COLD FRONT WILL BRING A PERIOD OF SHOWERS TO THE REGION LATE TONIGHT INTO FRIDAY FOLLOWED BY A DRYING TREND IN THE AFTERNOON. WARM WEATHER RETURNS SAT AHEAD OF A DRY COLD FRONT. CANADIAN HIGH PRESSURE BRINGS COOLER WEATHER SUNDAY...BEFORE A COASTAL LOW DELIVERS A WIND SWEPT SOAKING RAIN TO THE REGION LATE MON INTO MON NIGHT. COOLER WEATHER SHOULD DOMINATE NEXT WEEK WITH A FEW SHOWERS FROM TIME TO TIME. && .NEAR TERM /THROUGH FRIDAY/... 7 PM UPDATE... SATELLITE LOOP SHOWS LEADING EDGE OF CLOUD SHIELD ALREADY ENTERING NEW ENGLAND...SO SKIES WILL BECOME CLOUDY DURING FIRST PART OF TONIGHT. SHOWERS ARE NOT TOO FAR BEHIND ACROSS WESTERN NY AND SHOULD ARRIVE OVERNIGHT...SINCE IT WILL TAKE AWHILE FOR LOW LEVEL DRY AIR TO ERODE. FORECAST LOWS IN 40S ARE ON TRACK. FRIDAY... MID-LEVEL SHORTWAVE COMBINED WITH ISENTROPIC LIFT AND INCREASING MOISTURE WILL ALLOW FOR A CHANCE OF SHOWERS VERY LATE TONIGHT/EARLY TOMORROW MORNING. BY THE MORNING HOURS ON FRIDAY...EXPECT GENERALLY WIDESPREAD RAINFALL AS A COLD FRONT APPROACHES FROM THE WEST. ATMOSPHERE CONDITIONS APPEAR TO BE STABLE...AS WELL AS THE TIMING IS NOT FAVORABLE TO MENTION THUNDER. GUIDANCE INDICATES THAT PWATS WILL BE AROUND 1 INCH AND WITH THE MOISTURE FLUX BEING 2-3 STANDARD DEVIATIONS AWAY...COULD SEE VERY LOCALIZED HEAVY DOWNPOURS. HOWEVER THIS SYSTEM IS FAIRLY PROGRESSIVE AND SHOULD BE MOVING OUT OF THE REGION BY THE AFTERNOON HOURS. IN FACT SOME AREAS COULD SEE ONLY 0.1- 0.2 OF AN INCH FOR STORM TOTAL. AS PREV FORECASTER MENTIONED BEST LOCATION FOR HEAVIER RAIN IS ACROSS THE HIGHER TERRAIN FROM OROGRAPHIC LIFT. APPEARS THAT THE FRONT BECOME WEAK OR STALLS SOUTH OF THE PIKE DURING THE AFTERNOON HOURS. THIS MAY BE A FOCUS FOR A FEW DIURNALLY DRIVEN SHOWERS TO DEVELOP DUE TO STEEP LAPSE RATES AND A MOIST PROFILE STILL IN PLACE. THESE SHOWERS WILL BE ISOLATED IN NATURE. BECAUSE THE AFTERNOON SHOWERS WILL BE SO HIT OR MISS...APPEARS WE MAY REBOUND NICELY FOR TEMPS...REACHING IN THE LOW TO MID 60S. && .SHORT TERM /FRIDAY NIGHT/... TOMORROW NIGHT... SHORTWAVE ALOFT WILL PUSH COLD FRONT OFFSHORE. THIS WILL ALLOW FOR DRY WEATHER OVERNIGHT. AS SKIES CLEAR OUT EXPECT A VARIETY OF LOW TEMPS DROPPING TO THE LOW TO MID 40S ACROSS RADIATIONAL COOLING REGIONS AND LOW 50S FOR THE URBAN CITIES OF BOSTON AND PROVIDENCE. && .LONG TERM /SATURDAY THROUGH THURSDAY/... HIGHLIGHTS... * WARM/BREEZY SAT...AN ISOLATED SHOWER IN NE MA? * WIND SWEPT SOAKING RAIN LATE MON INTO EARLY TUE * COOLER/FEW SHOWERS MID WEEK GOOD AGREEMENT AMONG MODELS/ENSEMBLES ON LARGE SCALE PATTERN INTO EARLY NEXT WEEK WHICH LEADS TO FAIRLY HIGH CONFIDENCE. INITIALLY WE HAVE SPLIT FLOW ACROSS CONUS WITH POTENT NORTHERN STREAM SHORT WAVE DIVING OUT OF SE CANADA...BEFORE CLOSED LOW OVER DESERT SW EJECTS INTO PLAINS AND EVENTUALLY INTO WESTERN GREAT LAKES AS IT PHASES WITH NORTHERN STREAM. AFTER WARM AND DRY START TO WEEKEND... TRANSITION MON-TUE FAVORS SOAKING RAIN AS COASTAL LOW TAPS INTO SOUTHERN STREAM MOISTURE. FROM THERE PATTERN FAVORS TEMPERATURES THAT ARE MORE TYPICAL OF MID APRIL ALONG WITH FEW SHOWERS FROM TIME TO TIME. DETAILS FOR MORE SIGNIFICANT WEATHER IN EXTENDED FORECAST FOLLOW BELOW. SATURDAY...HIGH CONFIDENCE. FOCUS IS ON RATHER POTENT SHORT WAVE DIVING ACROSS NORTHERN NEW ENGLAND. WARM ADVECTION AHEAD OF IT AND DRY COLD FRONT SHOULD HELP HIGHS REACH UPPER 60S TO LOWER 70S AWAY FROM S COAST BASED UPON MODEL 2M TEMPERATURES. SHORT WAVE SHOULD BE ABLE TO GENERATE AT LEAST SCATTERED SHOWERS BUT EXPECT MOST OF ACTIVITY TO REMAIN TO OUR NE WHERE BETTER DYNAMICS AND DEEPER MOISTURE RESIDE. AIRMASS IS FAIRLY DRY OVER SOUTHERN NEW ENGLAND SO AT MOST AM ONLY EXPECTING ISOLATED SHOWERS ACROSS NE MA SAT AFTERNOON. MONDAY AND MONDAY NIGHT...HIGH CONFIDENCE. STILL LOOKING AT WIDESPREAD RAINFALL ACROSS SOUTHERN NEW ENGLAND... PROBABLY STARTING IN CT VALLEY BY LATE MORNING AND IN E MA TOWARD EARLY AFTERNOON...AND LASTING INTO EARLY TUE MORNING. INCREASING ONSHORE FLOW WILL KEEP HIGHS IN 50S MON...AS E/SE WINDS GUST TO 25- 30 MPH DURING AFTERNOON AND EVENING. SHORT WAVE EJECTING FROM OH VALLEY WILL RESULT IN SECONDARY LOW DEVELOPMENT ALONG FRONTAL BOUNDARY LATE MON INTO TUE WHICH TRACKS OVER SOUTHERN NEW ENGLAND. ENSEMBLES POINT TO ANOMALOUS SYSTEM FOR MID APRIL WITH DEPARTURES FOR LOW LEVEL SOUTHERLY WIND...MOISTURE FLUX AND PRECIPITABLE WATER RUNNING 2-3 STANDARD DEVIATIONS ABOVE CLIMATOLOGY. THIS ALL BRINGS POTENTIAL FOR HEAVY RAINFALL. 24HR MODEL QPF RANGES FROM 0.75 TO 1.5 INCHES...BUT 12Z ECMWF IS MORE ROBUST WITH WIDESPREAD 1.5 TO 2.0 INCHES. THOSE HIGHER TOTALS ARE CERTAINLY ATTAINABLE GIVEN FAIRLY HIGH GEFS PROBS OF 1 AND 2 INCHES. TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE. CLOSED LOW OVER WESTERN GREAT LAKES FAVORS CLOUDS...SPOTTY SHOWERS FROM TIME TO TIME /MAINLY DIURNAL/ AND SEASONABLE TEMPERATURES IN 50S. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE. VFR CIGS WILL STEADILY LOWER TO MVFR OVERNIGHT AND EARLY FRI MORNING AS SHOWERS ARRIVE. S FLOW PREVAILS WITH GUSTS TO AROUND 20KT FRI AFTERNOON. CONDITIONS IMPROVE TO VFR LATE FRI AFTERNOON AND FRI EVENING. KBOS TAF...HIGH CONFIDENCE. KBDL TAF...HIGH CONFIDENCE. OUTLOOK...SATURDAY THROUGH TUESDAY... SAT...VFR. MVFR POSSIBLE IN ISOLD SHOWERS ACROSS NE MA. NW WINDS GUST TO 25KT IN AFTERNOON. HIGH CONFIDENCE. SUN...VFR. HIGH CONFIDENCE. MON...MVFR/IFR DEVELOPING IN RAIN/FOG BY AFTERNOON. E/SE WIND GUSTING TO 25-30KT NEAR COAST. MODERATE CONFIDENCE. TUE...MVFR POSSIBLE IN SCT SHOWERS. MODERATE CONFIDENCE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE. SOUTHERLY FLOW ACROSS THE WATERS TONIGHT WILL INCREASE SEAS TO 3 FEET. EXPECT WIDESPREAD RAIN TO MOVE OVER THE WATERS LATE TONIGHT INTO EARLY TOMORROW WHICH COULD LOWER VSBYS. UNDERCUT WAVES ON FRIDAY AS WAVEWATCH APPEARS TO BE OVERDONE WITH TOO MUCH MIXING AND MOMENTUM TRANSFER TO THE OCEAN SURFACE. HOWEVER DID HOIST NEAR SHORE SMALL CRAFT ADV FOR 25 KT GUSTS COMING OFF THE SURFACE. WINDS WILL SWITCH TO THE WEST LATE FRIDAY INTO FRIDAY NIGHT BEHIND A SURFACE COLD FRONT. OUTLOOK...SATURDAY THROUGH TUESDAY... SATURDAY AND SUNDAY...HIGH CONFIDENCE. NOT ANTICIPATING NEED FOR ANY HEADLINES OVER WEEKEND. DRY COLD FRONT PUSHES OFFSHORE SAT AFTERNOON BUT WINDS AND SEAS SHOULD STAY JUST BELOW SCA AND REMAIN SO INTO SUN...AS HIGH PRESSURE BUILDS OVER REGION. MONDAY...MODERATE CONFIDENCE. INCREASING E/SE WINDS EXPECTED MON WITH BUILDING SEAS...PROBABLY REQUIRING SCA WITH GUSTS REACHING 25-30KT. OUTSIDE CHANCE OF REACHING MARGINAL GALES /35KT/ ESPECIALLY ON SOUTHERN WATERS. SEAS COULD REACH AS HIGH AS 8-10 FT ON OUTER WATERS MON NIGHT. RAIN AND FOG WILL LIMIT VSBY MON AFTERNOON AND AND MON NIGHT. TUESDAY...MODERATE CONFIDENCE. CONDITIONS IMPROVE SOMEWHAT TUE AS WINDS SUBSIDE AND SEAS GRADUALLY DIMINISH...BUT SEAS SHOULD REMAIN ROUGH ON OPEN WATERS THROUGH MOST OF DAY WHICH WOULD REQUIRE SCA. && .FIRE WEATHER... A QUICK MOVING SYSTEM WILL PASS OVER SOUTHERN NEW ENGLAND LATE TONIGHT INTO EARLY FRIDAY MORNING. THIS SYSTEM MAY DROP AROUND A TENTH OR TWO WHICH MAY NOT BE SUBSTANTIAL ENOUGH TO COUNTER THE RECENT DRY CONDITIONS. WINDS WILL INCREASE TO 25 MPH FRIDAY AFTERNOON ON THE BACK SIDE OF THIS SYSTEM. A DRY COLD FRONT WILL PASS OVER THE REGION ON SATURDAY BRINGING MORE DRY AIR AND GUSTY WINDS. ANTICIPATE MINIMUM RELATIVE HUMIDITY VALUES TO FALL DOWN TO 25 PERCENT AND WIND GUSTS REACHING 30 MPH. THIS COULD BRING FIRE WEATHER CONCERNS TO THE REGION DEPENDING ON HOW MUCH PRECIP FALLS ON FRIDAY. HIGH PRESSURE MOVES IN ON SUNDAY KEEPING THE WINDS GUSTS AT BAY...BUT ALLOWING FOR RH/S TO DROP NEAR 30 PERCENT AGAIN. CONDITIONS WILL TURN MORE WET BY NEXT WEEK WITH SEVERAL CHANCES OF SHOWERS AND COOLER WEATHER THROUGHOUT THE WORK WEEK. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EDT FRIDAY FOR ANZ230>236-251. && $$ SYNOPSIS...DUNTEN NEAR TERM...DUNTEN/JWD SHORT TERM...DUNTEN LONG TERM...JWD AVIATION...DUNTEN/JWD MARINE...DUNTEN/JWD FIRE WEATHER...DUNTEN

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