Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 132347 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 747 PM EDT SUN APR 13 2014 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH INTO CENTRAL AND NORTHERN NEW ENGLAND THIS EVENING. BREEZY CONDITIONS AND MILD TEMPERATURES ARE EXPECTED FOR MONDAY. A SLOW MOVING COLD FRONT WILL BRING A SOAKING RAIN LATE MONDAY NIGHT INTO TUESDAY NIGHT. DRIER AND MUCH COOLER CONDITIONS EXPECTED FOR THE MIDDLE AND END OF THIS WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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730 PM UPDATE...APPEARS THAT THE WARM FRONT MAY FINALLY BE MOVING N AS WINDS HAVE SHIFTING TO S AT KBOS...KORH AND KORE. HAVE SOME CONCERNS THIS FRONT MAY STALL WITH SUNSET...AND NOT MAKE IT TO MUCH FARTHER NORTH. SHOULD THIS SCENARIO OCCUR...TEMPERATURES AND WINDS WILL NEED MORE ADJUSTING LATER THIS EVENING. AT THIS POINT...SEEING MUCH STRONG SOUTH WINDS THAN NORTHEAST WINDS NORTH OF THE FRONT. THEREFORE..THINKING IT SHOULD CONTINUE TO CRAWL NORTH OVERNIGHT. EXPECT MAINLY CLEAR CONDITIONS TO CONTINUE THROUGH THIS EVENING... THOUGH SOME LOWER CLOUDS MAY START TO FORM ALONG THE SOUTH COAST AS TEMPERATURES BEGIN TO DROP. PREVIOUS DISCUSSION... WITH THE FRONT PUSHING INTO CENTRAL AND NORTHERN NEW ENGLAND BY EARLY TONIGHT...EXPECT TEMPS TO REMAIN IN THE LOWER-MID 50S. DEWPTS WILL LEVEL OFF IN THE UPPER 40S TO LOWER 50S OVERNIGHT. EXPECT AREAS OF LOW CLOUDS AND FOG TO DEVELOP BEGINNING THIS EVENING ALONG THE COAST...THEN WILL PUSH INLAND OVERNIGHT. WITH THE GOOD INFLUX OF LOW LEVEL MOISTURE ON THE S-SW WINDS...EXPECT PATCHY DRIZZLE TO DEVELOP ALONG THE S COAST...CAPE COD AND THE ISLANDS...MAINLY AROUND OR AFTER MIDNIGHT.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... MONDAY... AREAS OF FOG ALONG THE COAST AND PATCHY DRIZZLE ON THE S COAST SHOULD DISSIPATE BY AROUND MID MORNING AS TEMPS RISE AND S-SW WINDS INCREASE. SOME PATCHY FOG MAY LINGER ACROSS THE CAPE AND ISLANDS INTO MIDDAY. CLOUDS MAY ALSO LINGER ALONG THE S COAST...BUT SHOULD SEE SOME SUNSHINE THERE AS WELL. WITH A LOT OF SUNSHINE...EXPECT PRETTY GOOD MIXING IN PLACE. NOTING STRONG LAPSE RATES UP TO AROUND H9 ESPECIALLY INLAND SO SHOULD SEE SOME S-SW WINDS MIX DOWN. ALSO NOTING STRONG LOW LEVEL JET UP TO 45-50 KT AT BOTH H925 AND H850...SO HAVE MENTIONED GUSTS UP TO 30 KT POSSIBLE MAINLY ACROSS PORTIONS OF E MA INTO S CENTRAL NH. H85 TEMPS UP TO +12C TO +14C CROSS S NH DURING THE MORNING AND WITH THE GOOD WIND FLOW IN PLACE...TEMPS SHOULD REACH THE MID OR EVEN UPPER 70S IN S CENTRAL NH INTO THE MERRIMACK VALLEY OF MA. WILL BE SOMEWHAT COOLER ESPECIALLY ALONG THE S COAST WITH THE GOOD ONSHORE FLOW IN PLACE. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
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HIGHLIGHTS... * STRONG COLD FRONTAL PASSAGE TUESDAY INTO EARLY WEDNESDAY MORNING * BELOW AVERAGE TEMPERATURES FOR THE REMAINDER OF THIS WORK WEEK * MODERATING TEMPERATURES FRIDAY MODELS AND CONFIDENCE...OVERALL...13/12Z GUIDANCE REMAINS IN VERY GOOD AGREEMENT WITH THE HANDLING OF A SLOW MOVING COLD FRONT LATE MONDAY NIGHT INTO EARLY WEDNESDAY MORNING...AS WELL AS THE HIGH PRESSURE TO FOLLOW. BIGGER DIFFERENCES ARISE TOWARDS NEXT WEEKEND...WITH THE ECMWF DEPICTING A STRONGER SOUTHERN STREAM MID LEVEL TROUGH MOVING THROUGH THE EASTERN USA THAN THE GFS. THE GFS PLACES IS EMPHASIS ON A STRONGER CUTOFF IN THE NORTHERN STREAM INSTEAD. HAVE HIGH CONFIDENCE WITH RESPECT TO MOST OF THE DETAILS THROUGH FRIDAY...WITH LOWER THAN NORMAL CONFIDENCE IN THE DETAILS FOR NEXT WEEKEND. DISCOUNTED SOME OF THE WRF-BASED GUIDANCE...INCLUDING THE 13/15Z SREF...AS THEY APPEAR TO BE TOO SLOW MOVING THE COLD FRONT TROUGH OUR REGION. GENERALLY FAVORED A CONSENSUS SOLUTION OTHERWISE...TO SMOOTH OVER THE MINOR DIFFERENCES THROUGH FRIDAY. GAVE MORE OF AN EDGE TO THE ECMWF GUIDANCE TOWARD NEXT WEEKEND...AS IT WAS PREFERRED BY WPC AND THE GFS CUTOFF LOOKS ANOMALOUSLY TOO POTENT. DETAILS... MONDAY NIGHT INTO WEDNESDAY....LATEST GUIDANCE CONTINUES TO INDICATE THE DEVELOPMENT OF SEVERAL WAVES ALONG A SLOW MOVING COLD FRONT. THIS WILL ALLOW FOR MULTIPLE CHANCES FOR MODERATE TO HEAVY RAINFALL. AN AMPLIFYING LONGWAVE TROUGH OVER THE CENTRAL USA WILL SEND A COLD FRONT TOWARD NEW ENGLAND LATE TUESDAY INTO TUESDAY NIGHT...EXITING OUR REGION BY WEDNESDAY MORNING. A FEW SHOWERS MAY DEVELOP AHEAD OF THE FRONT MONDAY NIGHT...BUT BELIEVE THAT GUIDANCE IS PICKING UP MORE ON THE FOG AND DRIZZLE POTENTIAL DUE TO THE MARITIME AIR BEING ADVECTED ONSHORE FROM STRONG SOUTHERLY WINDS. THIS COLD FRONT SHOULD APPROACH BY LATE TUESDAY MORNING...PUSHING HEAVY RAINFALL FROM WEST TO EAST THROUGHOUT THE DAY. EXPECTING RAINFALL TO BE HEAVY AT TIMES AS A +4 STANDARD DEVIATION SOUTHERLY LOW-LEVEL JET TRANSPORTS ATLANTIC/GULF MOISTURE NORTH. PRECIPITABLE WATER VALUES ARE NEAR 1.5 INCHES...WHICH IS ABOUT +3 STANDARD DEVIATIONS ABOVE NORMAL. THUS THE INGREDIENTS ARE IN PLACE FOR A DECENT SOAKING. WE ANTICIPATE THE EVENING COMMUTE WILL BE THE MOST IMPACTED ACROSS DUE TO THE HEAVIER RAIN AND LOWER VISIBILITY. FINALLY THERE IS THE POSSIBILITY THAT A ISOLATED THUNDERSTORMS COULD DEVELOP ALONG THE LINE AT THE NOSE OF THE STRONG LOW-LEVEL JET. DUE TO LOW CONFIDENCE IN ITS OCCURRENCE...KEPT IT OUT OF THE FORECAST FOR NOW. SIGNIFICANTLY COLDER AIR WILL ARRIVE VERY LATE TUESDAY NIGHT INTO WEDNESDAY AS THIS FRONT PASSES TO THE EAST...WITH ANY LINGERING SHOWERS MIXING WITH OR CHANGING BRIEFLY TO SNOW. VERY LITTLE IF ANY ACCUMULATION IS EXPECTED. MINIMUM TEMPERATURES TUESDAY NIGHT SHOULD BE 15-20 DEGREES LOWER THAN THOSE MONDAY NIGHT. MUCH OF SOUTHERN NEW ENGLAND WILL BE AROUND FREEZING EARLY WEDNESDAY MORNING. WEDNESDAY AFTERNOON INTO FRIDAY...STRONG COLD FRONT WILL MOVE OFFSHORE BY WEDNESDAY MORNING. FOLLOWED BY STRONG SUBSIDENCE FROM A HIGH PRESSURE. ANOTHER UPPER LEVEL DIGGING TROUGH WILL BEGIN TO DEVELOP ACROSS THE WESTERN USA...ALLOWING FOR A STRONG RIDGE TO DEVELOP ACROSS THE NORTH ATLANTIC. THIS RIDGE WILL PUSH THE BUILDING HIGH OVER NEWFOUNDLAND AND LABRADOR YIELDING TO EASTERLY FLOW FOR OUR REGION. OVERALL ANTICIPATE DRY WEATHER WITH WELL BELOW NORMAL TEMPERATURES THROUGH THURSDAY NIGHT. TEMPERATURES WILL BE MODERATING FRIDAY DUE TO A BUILDING THERMAL RIDGE TRYING TO PUSH INTO OUR REGION. HOWEVER ALONG THE IMMEDIATE MASS COASTLINE TEMPERATURES WILL STRUGGLE ON ALL THREE DAYS TO GET ABOVE 50F DUE TO THE ONSHORE WIND. SATURDAY AND SUNDAY...OPERATIONAL GUIDANCE AS WELL AS THEIR ENSEMBLES INDICATE A POTENTIAL LOW PRESSURE IMPACTING SOUTHERN NEW ENGLAND NEXT WEEKEND. THERE IS LITTLE AGREEMENT IN THE DETAILS...BUT WE COULD BE LOOKING AT A SOGGY WEEKEND. HOWEVER THIS FAR OUT...HAVE LOW CONFIDENCE.
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&& .AVIATION /00Z MONDAY THROUGH FRIDAY/...
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LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY/... TONIGHT...MODERATE CONFIDENCE. EXPECT LOW CLOUDS AND FOG TO DEVELOP ACROSS PORTIONS OF RI/SE MA...THEN WILL SHIFT INLAND OVERNIGHT. LOCAL IFR-LIFR CIGS/VSBYS. PATCHY DRIZZLE ALSO FOR S COASTAL TERMINALS. LLWS AS SW LOW LEVEL JET MOVES ACROSS REGION. MADE SIGNIFICANT CHANGES TO KBOS TAF FROM 18Z ISSUANCE...AS TERMINAL TYPICALLY DOES NOT DROP BELOW MVFR WITH SOUTH WINDS. MONDAY...MODERATE CONFIDENCE. IFR-LIFR CONDITIONS EARLY...WHICH SHOULD IMPROVE BY MID-LATE MORNING. MVFR-IFR CIGS MAY LINGER ACROSS CAPE COD AND THE ISLANDS THROUGH MIDDAY. S-SW WINDS GUSTING TO 25-30 KT. CONTINUED LLWS THROUGH MIDDAY...SW WINDS 40-50 KT AT 2000 FT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. FRONTAL BOUNDARY JUST NORTH OF THE TERMINAL MAY SAG BRIEFLY SOUTH THIS EVENING... RESULTING IN A NORTHEAST WIND FOR A TIME. LOW CONFIDENCE THIS WILL HAPPEN AS SOUTH WINDS ARE STRONGER. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... TUESDAY-WEDNESDAY...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE IN TIMING. EXPECTING MVFR CONDITIONS TO DEVELOP FROM W-E DURING TUE MORNING IN RAIN. PERIODS OF HEAVY RAIN POSSIBLE TUE AFTERNOON/EVENING ACROSS CENTRAL AND WESTERN AREAS WITH AREAS OF IFR. RAIN MAY MIX WITH LIGHT SNOW AND/OR SLEET ACROSS S NH/W MA BEFORE ENDING LATE TUE NIGHT OR WED MORNING. CONDITIONS SHOULD IMPROVE TO VFR FROM W-E DURING WED. THURSDAY AND FRIDAY...HIGH CONFIDENCE. VFR.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE. TONIGHT...EXPECT S WINDS TO INCREASE OVERNIGHT. SEAS WILL ALSO BUILD. SMALL CRAFTS IN EFFECT. EXPECT AREAS OF FOG TO DEVELOP BEGINNING THIS EVENING THROUGH THE OVERNIGHT WITH LOCAL 1/4 MILE OR LESS. PATCHY DRIZZLE ALSO TO DEVELOP MAINLY ALONG THE S COASTAL WATERS. MONDAY...AREAS OF FOG AND DRIZZLE MAY LINGER INTO MID MORNING. EXPECT IMPROVING VSBYS BY MIDDAY OR EARLY AFTERNOON. SOUTH TO S-SW WINDS GUSTING UP TO 25-30 KT. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... MONDAY NIGHT...HIGH CONFIDENCE. FOG WILL DEVELOP ACROSS THE WATERS. STRONG SOUTHERLY WINDS WILL RESULT IN BUILDING SEAS. SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED. TUESDAY INTO THURSDAY...MODERATE CONFIDENCE. STRONG COLD FRONT WILL MOVE ACROSS THE WATERS TUESDAY INTO WEDNESDAY. EXPECTING GUSTY WINDS BEHIND THIS FRONT DUE TO STRONG COLD AIR ADVECTION. THERE IS A LOW PROBABILITY OF GALES TUESDAY EVENING INTO THE OVERNIGHT HOURS. SEAS WILL BUILD FURTHER IN RESPONSE. WINDS START TO RELAX LATE WEDNESDAY INTO THURSDAY...BUT SEAS WILL TAKE QUITE A BIT LONGER. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED. FRIDAY...HIGH CONFIDENCE. WINDS CONTINUE TO DIMINISH BELOW 25 KT. ROUGH SEAS LINGER ACROSS THE OUTER COASTAL WATERS. && .HYDROLOGY... WATER BEING ROUTED DOWNSTREAM FROM THE UPPER CONNECTICUT RIVER BASIN HAS RESULTED IN MINOR FLOODING AT BOTH HARTFORD AND MIDDLE HADDAM CT. FLOOD WARNINGS CONTINUE FOR THE CT RIVER AT THESE LOCATIONS. THOSE WITH INTERESTS ALONG LOWER REACHES OF CT RIVER SHOULD PAY ATTENTION TO THE LATEST FORECASTS AND CURRENT WATER LEVELS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT MONDAY FOR ANZ230>237-250- 251-254>256. && $$ SYNOPSIS...BELK/EVT NEAR TERM...BELK/EVT SHORT TERM...EVT LONG TERM...BELK AVIATION...BELK/EVT MARINE...BELK/EVT HYDROLOGY...STAFF

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