Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 160804 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 404 AM EDT WED APR 16 2014 .SYNOPSIS...
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ONCE A WINTRY MIX OF RAIN...SLEET AND SNOW COMES TO AN END THIS MORNING...HIGH PRESSURE WILL BRING A PERIOD OF DRY...BUT SEASONABLY COOL WEATHER TO THE REGION. LOW PRESSURE MAY BRING A ROUND OR TWO OF RAIN SHOWERS SOMETIME FRIDAY NIGHT INTO SATURDAY THEN DRY AND COOLER SUNDAY/MONDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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DUAL POL CC/ZDR PRODUCTS CONTINUES TO SHOW A BAND OF MODERATE TO EVEN HEAVY SLEET/SNOW PROGRESSING SLOWLY E ACROSS THE REGION THIS MORNING. CURRENT SETUP HAS IT MAINLY IN ERN CT AND THEN THROUGH MA/RI E OF WORCESTER COUNTY MA. HOWEVER...THE BACK END OF THE DRY AIR IN THE LOWEST LVLS IS ALSO RAPIDLY PROGRESSING E SUCH THAT CURRENT TIMING HAS IT REACHING THE CAPE/ISLANDS BY ABOUT 9-10Z OR SO. SO IT WILL BE A BATTLE BETWEEN THIS DRY AIR AND THE MIXING LINE ACROSS ERN MA/CT AND RI. HOWEVER GIVEN THE PROGRESSION IT IS LIKELY MOST AREAS WILL SEE A BRIEF CHANGE OVER TO A WINTRY MIX BEFORE PRECIP ENDS. ASIDE FROM THIS...THOSE AREAS WHICH HAVE SEEN SEVERAL HOURS OF MIXED PRECIP ARE REPORTING SOME SNOWFALL VALUES OF 1.0 TO 2.0+ INCHES OF MIXED SNOW/SLEET. THIS WILL COMBINE WITH TEMPERATURES WHICH ARE CONTINUING TO DECLINE AT OR BELOW FREEZING. WILL BE ISSUING AN SPS HIGHLIGHTING THE THREAT FOR TREACHEROUS TRAVEL ACROSS THE AREA EVEN AFTER THE PRECIPITATION HAS ENDED. WITH THE PRECIP NEARLY FINISHED BY AROUND 10-12Z EVERYWHERE...EXPECT RAPIDLY CLEARING SKIES AS WELL SUCH THAT SEVERAL AREAS IN WRN MA/CT AND SW NH MAY ACTUALLY BE ABLE TO SEE THE SUNRISE THIS MORNING. OTHERWISE TODAY...THE TREND WILL BE TOWARD CLEARING SKIES EVERYWHERE. HOWEVER DESPITE THIS...EVEN THOUGH MIXING SHOULD BE REASONABLY DEEP...H85 TEMPS WILL BE DROPPING TO ABOUT -10C. THEREFORE...DESPITE DECENT MID APRIL SUN...HIGHS TODAY WILL STRUGGLE TO BREAK OUT OF THE 40S IN MOST LOCALES. ONE FINAL NOTE...REMNANTS OF A 40 KT NW LLJ WILL LIKELY BE TAPPED SOMEWHAT EARLY TODAY AS WELL...ALTHOUGH IT WILL TAKE SOME TIME FOR THE MIXING TO EVEN REACH THE H92-H85 LAYER WHERE THIS RESIDES BEFORE IT EXITS TO THE E THIS AFTERNOON. THEREFORE...IT WILL BE A BREEZY START...BUT WITH WIND GUSTS GENERALLY CAPPING AT AROUND 30-35 MPH BEFORE DIMINISHING THIS AFTERNOON.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
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TONIGHT... HIGH PRES CRESTS OVER THE REGION. THIS SHOULD ALLOW FOR SKIES TO REMAIN MAINLY CLEAR AND WINDS TO BE FAIRLY LIGHT. THEREFORE...GOOD SETUP FOR RADIATIONAL COOLING IN AN ALREADY SEASONABLY COLD AIRMASS. EXPECT WITH INVERSIONS MOST AREAS AWAY FROM THE IMMEDIATE COAST TO DROP BELOW FREEZING...WITH SEVERAL AREAS IN THE LOW TO MID 20S. THU... HIGH PRES REMAINS IN CONTROL THANKS TO INVERTED RIDGING WITH THE CENTER OF THE HIGH SLIDING INTO THE CANADIAN MARITIMES. THIS SETUP ALLOWS WINDS TO SHIFT TOWARD THE E-NE THROUGH THE DAY. THEREFORE...DESPITE A CHANCE FOR TEMPS TO WARM SOMEWHAT WITH H85 TEMPS AROUND -1C E COASTAL LOCATIONS WILL ONCE AGAIN STRUGGLE TO BREAK OUT OF THE LOW 40S GIVEN SST VALUES THEMSELVES IN THE LOW TO MID 40S. AT OTHER INTERIOR LOCATIONS TEMPS SHOULD REBOUND TO THE MID TO UPPER 40S WITH SOME AREAS FINALLY BREAKING BACK INTO THE 50S AS WELL. SKIES SHOULD REMAIN MAINLY MOSTLY SUNNY...BUT SOME HIGH CLOUDS MAY SCRAPE S COASTAL LOCATIONS AS AN OCEAN WAVE PASSES WELL S OF THE AREA.
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&& .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * DRY BUT UNSEASONABLY CHILLY WED NIGHT * DRY WEATHER CONTINUES INTO FRI AND BECOMING MILDER INLAND * A PERIOD OF SHOWERS POSSIBLE FRI NIGHT INTO SAT BUT LOW CONFIDENCE AN ACTIVE AND SURPRISED NORTHERN STREAM JET THIS PERIOD WILL RESULT IN TEMPERATURES AT OR COOLER THAN NORMAL ALONG WITH A FEW CHANCES OF SHOWERS. VERY TYPICAL PATTERN FOR MID APRIL. DAILY DETAILS... WEDNESDAY NIGHT... CHILLY AIRMASS OVER THE REGION ALONG WITH MAINLY CLEAR SKIES AND DIMINISHING WINDS. THIS WILL RESULT IN COLD TEMPS OUTSIDE OF THE URBAN AREAS WITH MOST LOCATIONS IN THE 20S! THURSDAY AND FRIDAY... STRONG /1044 MB!/ HIGH PRESSURE ADVECTS INTO THE CANADIAN MARITIMES. THIS WILL EVOLVE INTO A COOL MARITIME AIRMASS FOR SOUTHERN NEW ENGLAND WITH LARGE TEMP DIFFERENCES FROM THE COAST TO INLAND. ACROSS EASTERN MA THE VERY CHILLY OCEAN WATERS WITH SSTS IN THE L40S WILL ACT LIKE A SNOWCOVER AND ENHANCE THIS COOL MARITIME AIRMASS. CHILLY ONSHORE WINDS WILL ADVECT THIS VERY COOL AND SHALLOW MARITIME AIRMASS INTO THE COASTAL PLAIN. THEREFORE ONLY EXPECTING HIGHS IN THE 40S OVER EASTERN MA...MEANWHILE STRONG APRIL SUN HEATS UP THE INTERIOR INTO THE 50S. AIRMASS CONTINUES TO MODIFY FRI WITH HIGHS 45- 50 EASTERN MA AND 55-60 WELL INLAND. FRIDAY NIGHT AND SATURDAY... MODELS CONTINUE TO STRUGGLE ON AMPLITUDE AND INTERACTION OF NORTHERN AND SOUTHERN STREAM WAVES. 12Z GFS REMAINS MORE ROBUST AND PHASING THAN THE 12Z ECMWF. THUS THE GFS IS THE WETTER SOLUTION OF THE TWO. ENSEMBLES INDICATE MORE STREAM SEPARATION AND ARE SLOWER PHASING THE STREAMS BUT THIS IS SOMEWHAT TYPICAL GIVEN THE LOWER RESOLUTION OF THE ENSEMBLES. TEMPS LIKELY REMAIN NEAR NORMAL...HIGHS IN THE 50S. SUNDAY/MONDAY/TUESDAY... AS EXPECTED LOTS OF TIMING ISSUES HERE GIVEN THE FAST FLOW ACROSS THE NORTHERN STATES. GIVEN THIS FLOW REGIME AND TIME RANGE HERE WILL FOLLOW A MODEL BLEND WHICH YIELDS TEMPS NEAR NORMAL AND A RISK OF SHOWERS IN THE MON NIGHT/TUE TIME FRAME. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
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LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH THURSDAY/... THROUGH 12Z...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. MIX OF MAINLY MVFR/IFR WILL GIVE WAY TO VFR FROM W TO E THROUGH 12Z. WITH VFR EXPECTED AS PRECIP ENDS. ANY AREAS CURRENTLY RAINING ALSO EXPECTED TO CHANGE TO A SLEET AND SNOW MIX FOR A BIT BEFORE ENDING AS WELL...AND TRIED TO TIME THIS AS CLOSE AS POSSIBLE IN THE TAFS. NW WINDS WITH GUSTS 20-25 KT CONTINUE. AFTER 12Z TODAY THROUGH THURSDAY...HIGH CONFIDENCE. MAINLY VFR. NW WINDS GUST 20-30 KT AT TIMES THROUGH THE MORNING...BUT THEN DIMINISH THROUGH THIS AFTERNOON AND EVENING. WINDS SHIFT TO THE N...THEN NE BY TOMORROW. KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT TIMING. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... THURSDAY THRU FRIDAY...VFR VSBYS LIKELY WITH MVFR CIGS POSSIBLE...HIGHEST PROBABILITY ACROSS RI AND EASTERN MA. FRIDAY NIGHT INTO SATURDAY...MVFR IN SCATTERED SHOWERS POSSIBLE BUT CONFIDENCE IS VERY LOW. SUNDAY...IMPROVING TREND WITH VFR LIKELY ALONG WITH INCREASING NW WINDS.
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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. NW GALE FORCE WINDS WILL CONTINUE ACROSS THE WATERS THROUGH MID MORNING...FOLLOWED BY A RAPID DECLINE IN WINDS. HOWEVER...SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR AT LEAST THE OCEAN WATERS THROUGH THE OVERNIGHT AND INTO THE DAY TO TOMORROW FOR SEAS ALONE. WHICH WILL FALL FROM 7-10 FT TO AN AVERAGE OF 5-7 FT BY TOMORROW MORNING. OTHERWISE...E-NE WINDS WILL ONCE AGAIN GUST AROUND 25 KT ON THE SRN WATERS DURING THE DAY TOMORROW...SO SMALL CRAFT ADVISORIES WOULD BE NEEDED ANYWAY FOR WINDS. IN ESSENCE...SMALL CRAFT ADVISORIES CONTINUE ACROSS THE REGION THROUGH MOST OF THE PERIOD..SAVE FOR THE NEAR SHORE WATERS LATE TODAY AND TONIGHT ONCE WINDS RECEDE. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... THU NIGHT THRU FRI...TREND HERE WILL BE DECREASING SOUTHERLY SWELLS WITH INCREASING ENE WIND WAVES. MAINLY DRY WITH MARITIME AIRMASS OVER THE WATERS COURTESY OF 1040 MB HIGH ACROSS NEWFOUNDLAND. FRI NIGHT AND SAT...LOW CONFIDENCE FORECAST WITH LOW PRES APPROACHING FROM THE SOUTH AND ANOTHER FROM THE GREAT LAKES. DILEMMA WILL BE HOW MUCH SEPARATION BETWEEN THESE SYSTEMS OR IF LOWS WILL MERGE INTO ONE STRONGER SYSTEM. STILL TOO EARLY TO SAY. SUNDAY...IMPROVING TRENDS WITH LOW PRES STRENGTHENING WELL EAST OF NEW ENGLAND FOLLOWED BY A MODEST NW WIND.
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&& .HYDROLOGY...
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SEVERAL POINTS ALONG THE CT RIVER ARE FLOODING OR WILL BE IN MINOR FLOOD SOON. WARNINGS CONTINUE FOR THE CT RIVER AT... THOMPSONVILLE HARTFORD MIDDLE HADDAM MONTAGUE NORTHAMPTON OTHER POINTS ALONG THE CT RIVER WILL NEED TO BE WATCHED AS WATER CONTINUES TO RUNOFF FROM RAINS OVERNIGHT AND YESTERDAY AS WELL AS DRAINAGE FROM RAIN AND MELTING SNOW ACROSS NRN NEW ENGLAND. IT MAY TAKE THROUGH THE END OF THE WEEK FOR SOME OF THE WATERS TO RECEDE BELOW FLOOD STAGE AT SOME OF THESE POINTS. ALSO...NOTE THAT IT IS POSSIBLE SOME OF THESE MAY ALSO REACH MODERATE FLOOD AT SOME POINT LATER IN THE NEXT COUPLE OF DAYS AS WELL BEFORE THEY RECEDE. OUTSIDE OF THE CT RIVER...THE PAWCATUCK AT WESTERLY CONTINUES TO RISE AS WELL AND MAY NEED TO BE MONITORED FOR POTENTIAL FLOODING LATER IN THE OVERNIGHT TONIGHT. BUT GIVEN THERE IS TIME TO MONITOR THE RESPONSE NO WARNING IS CURRENTLY OUT.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...GALE WARNING UNTIL NOON EDT TODAY FOR ANZ230>234-236-250-251. GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR ANZ235-237-256. GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ254-255.
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&& $$ SYNOPSIS...DOODY/GAF NEAR TERM...DOODY SHORT TERM...DOODY LONG TERM...GAF AVIATION...DOODY/GAF MARINE...DOODY/GAF HYDROLOGY...STAFF

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