Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 141100 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 700 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 EXITING THE REGION BY EARLY WEDNESDAY MORNING. DRIER AND MUCH COOLER CONDITIONS EXPECTED FOR WEDNESDAY AND THURSDAY WITH TEMPERATURES MODERATING BY FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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7PM UPDATE... OVERALL TREND IN THE FORECAST REMAINS ON TRACK FOR TODAY. WARM FRONT IS CURRENTLY STALLED ACROSS KEEN TO KASH TO KBVY. IN FACT BEDFORD JUMPED FROM 41 TO 59 WITHIN AN HOUR. EXPECT THE FRONT TO PUSH NORTHWARD WITHIN THE NEXT FEW HOURS ALLOWING FOR THE REST OF THE REGION TO BE IN THE WARM SECTOR. STRONG SOUTHERLY WINDS CONTINUES TO ADVECT WARM MOIST AIR INTO THE REGION. THIS HAS ALLOWED FOR PATCHY FOG TO DEVELOP ACROSS THE SOUTH COAST AND ISLANDS. HOWEVER THE GUSTY WINDS ARE KEEPING THE VSBYS DROPPING BELOW 2SM. ADJUSTED FORECAST TO ACCOUNT FOR CURRENT CONDITIONS. PREVIOUS DISCUSSION... 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.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... 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. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * COLD FRONT WILL EXIT THE REGION WED MORNING * BELOW AVERAGE TEMPS FOR THE REMAINDER OF THE WORK WEEK * MODERATING TEMPS FRIDAY MODELS AND CONFIDENCE... OVERALL 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT FOR THE POTENT COLD FRONT WHICH WILL EXIT THE REGION TUESDAY NIGHT INTO EARLY WED MORNING. MODELS CONTINUE TO SHOW STRONG HIGH PRESSURE IN THE WAKE OF THIS FRONT LEADING TO DRY WEATHER. THE NEXT FEATURE TO FOCUS ON IS ANOTHER TROUGH ALOFT PROGRESSING ACROSS THE LOWER 48 BY THE END OF THE WEEK. GUIDANCE HAS BEEN INDICATING MULTIPLE UNCERTAINTIES WITH THIS FEATURE INCLUDING DISTRIBUTION OF ENERGY WITHIN THE FLOW AND THE TIMING. HOWEVER AS THIS SYSTEM DIGS INTO THE CONUS...STRONG RIDGING WILL BUILD EAST OF THE REGION. INCREASING CONFIDENCE IN THE FORECAST WITH HIGH CONFIDENCE THAT WET WEATHER WILL OCCUR TUESDAY NIGHT AND EXIT THE REGION BY 12Z WEDNESDAY. THERE IS STILL SOME UNCERTAINTY ON WHERE THE HEAVIEST PRECIP WILL OCCUR BUT BELIEVE ACROSS CT AND SOUTH OF THE MASS PIKE WILL SEE THE HIGHER QPF AMOUNTS. OTHERWISE MODERATE CONFIDENCE THAT HIGH PRESSURE WILL DOMINATE THE REMAINDER OF THE WEEK WITH LOW CONFIDENCE ON POTENTIAL WET WEATHER FOR NEXT WEEKEND. DETAILS... TUESDAY NIGHT INTO WEDNESDAY.... A COLD FRONT WILL PUSH HEAVY PRECIP FROM WEST TO EAST OVERNIGHT AND BE OUT OF THE REGION BY WED MORNING. EXPECT RAINFALL TO BE HEAVY AT TIMES AS A SOUTHERLY LLJ TRANSPORTS ATLANTIC/GULF MOISTURE WITH PW NEAR 1.5 INCHES...WHICH IS 4 STANDARD DEVIATIONS AWAY...INTO THE REGION. ANTICIPATE THAT THE EVENING COMMUTE WILL BE IMPACTED THE MOST ACROSS THE REGION DUE TO THE HEAVY RAINFALL...LOWER VSBYS AND PONDING ACROSS ROADWAYS. FINALLY THERE IS THE POSSIBILITY THAT A RUMBLE OF THUNDER COULD DEVELOP ALONG THE LINE. ALTHOUGH GUIDANCE IS A LITTLE ON THE WEAKER SIDE...SHOWALTERS ARE STILL BELOW ZERO INDICATING FOR MORE ELEVATED CONVECTION. ALSO WITH STRONG 925MB LLJ BETWEEN 50-70KTS...ANY STRONG SHOWERS THAT DEVELOP COULD TAP INTO THESE STRONG WINDS ALOFT RESULTING IN SOME GUSTY WINDS WITHIN THESE SHOWERS THAT WOULD GENERALLY LOOK WEAKER. BECAUSE OF THIS HAVE INSERTED ISOLATED THUNDER INTO THE FORECAST BUT WILL NEED TO MONITOR FOR POTENTIAL GUSTY WINDS. COLDER AIR WILL FILTER IN VERY LATE TUE NIGHT INTO WED AS THE FRONT PASSES TO THE EAST...WITH ANY LINGERING SHOWERS EXPECT MIXING OR A CHANGE SNOW VERY BRIEFLY. VERY LITTLE IF ANY ACCUMULATION IS EXPECTED. BECAUSE OF THIS STRONG CAA MOVING INTO REGION EXPECT A RAPID DROP IN TEMPERATURES. THERE IS A LOW PROBABILITY FOR A FLASH FREEZE POTENTIAL BUT CONFIDENCE IS LOW. WEDNESDAY AFTERNOON INTO FRIDAY... STRONG COLD FRONT WILL MOVE OFFSHORE BY WED MORNING. FOLLOWED BY STRONG SUBSTANCE AND A BUILDING HIGH PRESSURE SYSTEM. ANOTHER UPPER LEVEL DIGGING TROUGH WILL BEGIN TO DEVELOP ACROSS THE WESTERN CONUS...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 THE REGION. OVERALL ANTICIPATE DRY WEATHER WITH WELL BELOW AVG TEMPS FOR WED AND THURS. TEMPERATURES WILL BE COLD AND RAW ALONG THE EAST COASTLINE AS EASTERLY ONSHORE FLOW WILL DOMINATE THROUGH THE REMAINDER OF THE WEEK. DROP TEMPERATURES WED NIGHT BY SEVERAL DEGREE BELOW GUIDANCE AS STRONG HIGH PRESSURE WILL KEEP SKIES CLEAR AND WINDS LIGHT. TEMPS WILL FEEL MORE LIKE EARLY MARCH...AND COULD MAKE A RUN AT RECORDS. ANY VEGETATION THAT DECIDED TO START GROWING THIS PAST WEEK...DUE TO THE ABOVE NORMAL TEMPS...WILL NEED TO BE COVERED AS TEMPS WILL DROP BELOW FREEZING. NO PLANS FOR FREEZE HEADLINES AS GROWING SEASON DOES NOT START UNTIL APRIL 20TH. FRIDAY TEMPS WILL BE MODERATING DUE TO BUILDING THERMAL RIDGE TRYING TO PUSH INTO THE REGION. HOWEVER EXPECT TEMPS ALONG THE IMMEDIATE MASS COASTLINE TO STILL BE WELL BELOW AVERAGE. IN FACT IT DOESN`T LOOK LIKE THE CAPE OR EVEN BOSTON WILL GET ABOVE 50 UNTIL SAT OR MAYBE SUNDAY. SATURDAY AND SUNDAY... GUIDANCE AS WELL AS THERE ENSEMBLES ARE INDICATING A WAVE MOVING ACROSS THE GREAT LAKES REGION LATE FRIDAY AND INTO SATURDAY RESULTING IN A SYSTEM MOVING TOWARDS NEW ENGLAND. THIS COULD RESULT IN A SOGGY AND COOLER WEEKEND. HOWEVER THIS FAR OUT...HAVE LOW CONFIDENCE. && .AVIATION /12Z 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 7AM UPDATE... 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 THE REGION BEHIND A STRONG COLD FRONT 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 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-SOUTHWESTWINDS 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 POSSIBILITY FOR GALES TUESDAY EVENING INTO THE OVERNIGHT HOURS...A GALE WATCH HAS BEEN ISSUED. 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. 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. && .BOX WATCHES/WARNINGS/ADVISORIES... 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. && $$ SYNOPSIS...WTB/DUNTEN NEAR TERM...WTB/DUNTEN SHORT TERM...WTB LONG TERM...DUNTEN AVIATION...WTB/DUNTEN MARINE...WTB/DUNTEN HYDROLOGY...

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