Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 140753 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 353 AM EDT MON APR 14 2014 .SYNOPSIS... GUSTY SOUTHWEST WINDS WILL BRING MILD TEMPERATURES TODAY AND TUESDAY. A SLOW MOVING COLD FRONT WILL BRING A SOAKING RAIN TUESDAY BEFORE MOVING THROUGH NEW ENGLAND EARLY TUESDAY NIGHT. DRIER AND MUCH COOLER CONDITIONS EXPECTED FOR THE MIDDLE AND END OF THIS WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THROUGH 8 AM/12Z... AREAS OF FOG AND LOW CLOUDS OVER CAPE COD AND ISLANDS CAUSED BY HIGHER DEWPOINT AIR MOVING OVER THE THE COLDER WATERS OF THE BAYS AND SOUNDS. THIS SHOULD CONTINUE THROUGH THE REMAINDER OF THE NIGHT. WINDS ARE NEAR CALM IN SOME INTERIOR SPOTS...AND WITH INCREASING DEWPOINTS THERE WILL BE SOME PATCHES OF FOG UNTIL SUNRISE. WARM FRONT LINGERS OVER NORTHEAST MASS/SOUTHCENTRAL NH WITH TEMPS IN THE 40S TO THE NORTH AND 50S/LOW 60S TO THE SOUTH. TEMPS SHOULD BE NEAR STEADY EXCEPT FOR ANY WARMING IN THE NORTHEAST AS THE WARM FRONT SLOWLY MOVES NORTH. PATCHES OF MID AND HIGH CLOUDS MOVING ACROSS FROM NEW YORK WILL CROSS SOUTHERN NEW ENGLAND THE REST OF THE NIGHT. TODAY... AREAS OF FOG AND LOW CLOUDS SHOULD DISSIPATE BY MID MORNING. STRONG SOUTHWEST WINDS ALOFT /40-50 KNOTS/ WILL PUSH THE SURFACE WARM FRONT NORTHEAST OF THE MERRIMACK VALLEY. DYNAMICS AND DEEP MOISTURE WILL REMAIN WELL TO THE WEST...SO EXPECT A DRY WEATHER DAY. TEMPERATURES IN THE WARM SECTOR WILL START THE DAY MILD. MIXING SHOULD REACH TO AT LEAST 925 MB...TEMPS AT THAT LEVEL AND AT 900 MB WOULD SUPPORT MAX SFC TEMPS IN THE MID 70S. SOUTH- SOUTHWEST WIND OFF THE WATERS WILL KEEP THE SOUTH COAST COOLER...55-65. OBSERVED WINDS THROUGH THOSE LEVELS ARE 35-40 KNOTS...MUCH COULD MIX TO THE SURFACE. WE ARE ESTIMATING GUSTS TO 30 KNOTS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
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TONIGHT... UPPER RIDGE OVER THE EASTERN USA SHIFTS OFFSHORE AS AN UPPER TROUGH DIGS OVER THE GREAT LAKES. THIS WILL SLOW THE FORWARD PROGRESS OF A COLD FRONT OVER THE GREAT LAKES AS WELL AS THE SUPPORTING JET DYNAMICS. IT WILL ALSO DRAW MORE HUMIDITY NORTH INTO NEW ENGLAND. EXPECT A BROAD AREA OF SHOWERS OVER NY AND PA...AND A CHANCE OF A FEW SHOWERS REACHING THE BERKSHIRE EAST SLOPES AND THE CT VALLEY TOWARD MORNING. OTHER CONCERN WILL BE FOG/DRIZZLE DEVELOPMENT. BEST CHANCE WILL AGAIN BE ALONG THE SOUTH COAST AND ISLANDS AS THE HUMID AIR MOVES OVER THE COLDER WATERS OFF OUR SOUTH COAST. TUESDAY... RIGHT ENTRANCE REGION OF THE UPPER JET MOVES ACROSS NEW ENGLAND DURING TUESDAY. STRONG LOW LEVEL JET WILL BRING GULF AND ATLANTIC MOISTURE OVER OUR AREA. CROSS SECTIONS SHOW A DEEP COLUMN OF MOISTURE. PRECIPITABLE WATER VALUES ARE FORECAST AT 1.5 INCHES WHICH IS 2-3 STD DEV ABOVE NORMAL FOR APRIL. STABILITY VALUES ARE MOSTLY UNFAVORABLE...BUT TOTALS ARE 45-49 SO THUNDER IS NOT OUT OF THE QUESTION. OVERALL...A WET DAY. AS WE WILL BE IN THE WARM SECTOR...WE FAVORED CONVECTIVE WORDING /SHOWERS/. THE LOW LEVEL JET WILL INCREASE TO 60-70 KNOTS WHICH WILL FAVOR SOUTHERLY SURFACE GUSTS OF 35-40 KNOTS AND POSSIBLY A LITTLE MORE. A WIND ADVISORY MAY EVENTUALLY BE NEEDED.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * STRONG COLD FRONTAL PASSAGE TUESDAY NIGHT 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... TUESDAY NIGHT AND WEDNESDAY MORNING... 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. 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. && .AVIATION /07Z 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 TUESDAY/...HIGH CONFIDENCE IN TRENDS BUT MODERATE CONFIDENCE IN TIMING THROUGH 12Z/8 AM... FOG AND LOW CLOUDS DEVELOPING OVERNIGHT. PRIMARY LOCATION SHOULD BE ALONG THE SOUTH COAST AND ISLANDS OF RI AND MASS WITH CIGS BELOW 1000 FEET AND VSBYS 1-3 MILES. PATCHY MVFR VSBYS IN FOG POSSIBLE ELSEWHERE IN SOUTHERN NEW ENGLAND AS HUMIDITY INCREASES. STRONG WINDS JUST OFF THE SURFACE WITH OBSERVED 35-40 KNOTS. THIS WILL CAUSE LOW LEVEL WIND SHEAR. TODAY... AREAS OF FOG AND LOW CLOUDS WILL INITIALLY BRING IFR CONDITIONS ALONG THE SOUTH COAST...BUT THIS SHOULD DISSIPATE DURING THE MORNING. MOST AREAS WILL BE VFR WITH SOME MID AND HIGH CLOUDS. GUSTY SOUTH-SOUTHWEST WIND AT THE SURFACE WITH 30 KNOT WINDS. WINDS AT 2000-3000 FEET WILL INCREASE TO 40-50 KNOTS CONTINUING LOW LEVEL WIND SHEAR THROUGH THE DAY. TONIGHT... THE HUMID ENVIRONMENT WILL ALLOW CLOUDS WITH MVFR CIGS TO DEVELOP. SOME PATCHY FOG IS POSSIBLE WITH MVFR VSBYS. CONTINUED STRONG WINDS AT 2000 FEET WITH RESULTING LOW LEVEL WIND SHEAR. TUESDAY... COLD FRONT APPROACHES FROM THE GREAT LAKES WITH SHOWERS DEVELOPING FROM WEST TO EAST. A FEW SHOWERS MAY REACH THE CT VALLEY AROUND SUNRISE...THEN SPREAD EAST THROUGH THE MORNING. EXPECT IFR CIGS/VSBYS IN RAIN AND FOG FROM MIDDAY THROUGH EVENING. ALSO A POTENTIAL FOR SCATTERED OR ISOLATED THUNDERSTORMS TUESDAY AFTERNOON/EVENING. GUSTY SOUTH WINDS 35 KNOTS...POSSIBLY 40 KNOTS. CONTINUED STRONG WINDS AT 2000 FEET WITH LOW LEVEL WIND SHEAR. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT-WEDNESDAY...HIGH CONFIDENCE IN TRENDS...MODERATE CONFIDENCE IN TIMING. 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...
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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 TUESDAY/...HIGH CONFIDENCE. TODAY...AREAS OF FOG AND LOW VSBYS POSSIBLE EARLY...BUT OTHERWISE FAIR SKIES AND GOOD VSBYS. INCREASING SEAS AND SOUTH-SOUTHWEST WINDS WITH GUSTS EXPECTED AROUND 30 KNOTS...SEAS REACHING 5-8 FEET ON THE EXPOSED WATERS. A SMALL CRAFT ADVISORY FOR ALL WATERS CONTINUES. TONIGHT...FOG AND LOW VSBYS AGAIN POSSIBLE. STRONG SOUTH-SOUTWEST WINDS WITH 25-30 KNOT GUSTS. SEAS CONTINUE AT 5-8 FEET ON THE EXPOSED WATERS. TUESDAY... RAIN SHOWERS MOVE ACROSS THE WATERS...SOME HEAVY DOWNPOURS AND ISOLATED THUNDER/LIGHTNING. POOR VSBYS IN RAIN AND FOG. WINDS OVERHEAD WILL INCREASE WITH SPEEDS OF 60-70 KNOTS AT 2000 FEET...AND SOME OF THIS WILL REACH THE SURFACE IN GUSTS. THESE WINDS WILL HAVE THE POTENTIAL TO REACH GALE FORCE. A GALE WATCH HAS BEEN ISSUED FOR ALL WATERS FOR TUESDAY AFTERNOON/EVENING. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT INTO THURSDAY...MODERATE CONFIDENCE. STRONG COLD FRONT WILL MOVE ACROSS THE WATERS TUESDAY NIGHT 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.
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&& .HYDROLOGY...
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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. HEAVY DOWNPOURS ASSOCIATED WITH THE APPROACHING COLD FRONT TUESDAY AND TUESDAY NIGHT MAY PRODUCE 1-2 INCHES OF RAINFALL. THIS WILL BE A CONCERN FOR PRODUCING URBAN/POOR DRAINAGE FLOODING. IT WILL ALSO RAISE RIVER LEVELS JUST AS SNOWMELT IS WORKING ITS WAY SOUTH. WE WILL CONTINUE TO MONITOR WITH AN EYE TOWARD EVENTUALLY ISSUING A FLOOD WATCH.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...GALE WATCH FROM TUESDAY AFTERNOON THROUGH LATE TUESDAY NIGHT FOR ANZ230>237-250-251-254>256. SMALL CRAFT ADVISORY UNTIL 2 PM EDT TUESDAY FOR ANZ230>237-250- 251-254>256.
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&& $$ SYNOPSIS...WTB/BELK NEAR TERM...WTB SHORT TERM...WTB LONG TERM...BELK AVIATION...WTB/BELK MARINE...WTB/BELK HYDROLOGY...

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