Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 191852 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 252 PM EDT SAT APR 19 2014 .SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE IN CONTROL WILL RESULT DRY WEATHER INTO TUESDAY. MILD AFTERNOON/S EXCEPT FOR CHILLY SEA BREEZES ALONG THE COAST SUNDAY. A LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL LIKELY BRING A PERIOD OF WET WEATHER TUESDAY AFTERNOON INTO WEDNESDAY. ANOTHER HIGH PRESSURE ARRIVES WITH MORE DRY...PLEASANT CONDITIONS FOR LATE NEXT WEEK.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
STRONG HIGH PRESSURE WILL BUILD SOUTH FROM EASTERN CANADA. THIS WILL RESULT IN MAINLY CLEAR SKIES AND LIGHT WINDS...WHICH ARE NEAR IDEAL RADIATIONAL COOLING CONDITIONS. LOW TEMPERATURES WILL BOTTOM OUT IN THE LOWER TO MIDDLE 20S ACROSS PORTIONS OF SOUTHWEST NH/NORTHWEST MA...TO MAINLY THE UPPER 20S TO MIDDLE 30S ELSEWHERE. THESE READINGS ARE QUITE COLD FOR THE LATTER HALF OF APRIL...BUT WILL BE SHY OF ANY RECORDS.
-- End Changed Discussion --
&& .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
-- Changed Discussion --
HIGH PRESSURE OVER EASTERN CANADA WILL SHIFT TO A POSITION JUST SOUTH OF THE MARITIMES LATE SUNDAY NIGHT. THIS WILL RESULT IN MOSTLY CLEAR SKIES...BUT ALSO ONSHORE WINDS. SINCE THE WATER IS STILL RATHER COLD...TEMPERATURES ALONG THE IMMEDIATE COAST SHOULD HOLD IN THE 45-50 DEGREE RANGE. ELSEWHERE...PLENTY OF SUNSHINE SHOULD BOOST MAX TEMPERATURES WELL INTO THE 50S. A FEW LOCATIONS NEAR THE CT AND MERRIMACK RIVER VALLEYS MAY REACH AROUND 60 DEGREES. WINDS WILL BE MUCH LIGHTER THAN TODAY...SO IT WILL BE A PLEASANT AFTERNOON INLAND FROM THE COAST. NOT AS IDEAL RADIATIONAL COOLING CONDITIONS SUNDAY NIGHT...SO EXPECTING SEASONABLE TEMPERATURES.
-- End Changed Discussion --
&& .LONG TERM /MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
OVERVIEW AND MODEL PREFERENCES... 19.00Z MODEL GUIDANCE SUITE SHOWING REASONABLY GOOD AGREEMENT IN THE SYNOPTIC SCALE THROUGH THE LONG TERM. THIS IS EVEN WITHIN A SPLIT FLOW REGIME WHICH IS EXPECTED TO TRANSITION FROM ZONAL TO MORE AMPLIFIED BY LATE IN THE WEEK. THERE ARE SOME TYPICAL BIASES APPARENT BY THE LATTER HALF OF THE WEEK REGARDING A POTENTIAL WAVE OF LOW PRES FOR THIS COMING WEEKEND. WITH THE AGREEMENT THROUGH MOST OF THE PERIOD A CONSENSUS BLEND OF OPERATIONAL AND ENSEMBLE GUIDANCE WILL BE USED...BUT WITH MORE WEIGHT ON ENSEMBLE MEANS WHICH AGREES WITH LATEST WPC LONG RANGE THINKING. AS MENTIONED ABOVE...A ZONAL SPLIT FLOW WILL GIVE WAY TO MORE AMPLIFIED FLOW AS SRN AND NRN STREAM WAVES PHASE TO CREATE A LONGWAVE TROF IN VICINITY OF THE GREAT LAKES BY MID WEEK. THIS WILL YIELD A DRY-WET TRANSITION FROM MON INTO TUE NIGHT-WED. HOWEVER...THIS MORE AMPLIFIED PATTERN DOES FEATURE A STRONGER RIDGE TO FOLLOW FOR THE LATTER HALF OF THE WEEK. HOWEVER...BECAUSE OF THE DIFFICULTY GUIDANCE HAS WITH THESE MORE AMPLIFIED FLOW PATTERNS TOWARD THE ENDS OF THEIR CYCLES...THERE IS A LOT OF VARIANCE WITH YET ANOTHER LOW PRES WAVE FOR THE WEEKEND. HOWEVER...THE PROPOSED BLEND SHOULD AT LEAST HIT THE MAIN POINTS. DETAILS... MON...A SFC RIDGE INVERSION REMAINS IN CONTROL INTO THE THE DAY TUE SUPPORTING A DRY FORECAST EVEN AS A WARM FRONT SLIDES INTO NRN NEW ENGLAND. AFTER A COOL START MON MORNING WITH H85 TEMPS AVERAGING +7C AND FULL MIXING UNDER PARTLY CLOUDY SKIES...SFC TEMPS ARE EXPECTED TO REBOUND TO THE MID 60S. S-SW WINDS MAINLY AROUND 10 MPH ON MON MAY ALLOW FOR A WEAK SEA BREEZE EVEN ON THE E COAST...BUT THIS WOULD BE SHALLOW AND ONLY WITHIN A FEW MILES OF THE SHORE. MON NIGHT INTO TUE WEAK WARM ADVECTION SHOULD KEEP LOWS IN THE 40S...WITH MID-HIGH CLOUDS BUILDING OVER DURING THE DAY TUE. THESE CLOUDS SHOULD STILL ALLOW FULL MIXING TO H85 THOUGH...WHERE TEMPS ARE CLOSER TO +10C. THEREFORE...WARMER TEMPS ON TUE...WITH SOME LOCATIONS BREAKING INTO THE 70S IN SPITE OF THE INCREASING CLOUDS. TUE NIGHT INTO WED... SFC COLD FRONT WILL BE APPROACHING THEN CROSSING THE REGION INTO THE EARLY HALF OF THE DAY ON WED. AM NOTING THE GUIDANCE DOES SUPPORT A SECONDARY FRONTAL WAVE SLIDING ALONG THIS FRONT ALONG WITH A MODEST 30-40 KT LLJ. THIS SUGGESTS IT MAY BE A LITTLE SLOWER MOVING THAN SOME ENSEMBLE MEMBERS SUGGEST...AND THE OPERATIONAL ECMWF IS A BIT SLOWER. THEREFORE...WILL SLOW THE OVERALL RAIN THREAT...ALLOWING IT TO CONTINUE INTO MID DAY WED. MODEST LIFT AND PWATS AROUND 1.0 SUGGESTS WIDESPREAD RAIN EVENT...BUT NOT AS STRONG AS SOME EARLIER THIS SPRING. MOST QPF AMOUNTS SHOULD LIE SOMEWHERE BETWEEN 0.25 AND 0.5 INCHES GIVEN ITS SLIGHTLY FASTER MOVEMENT AND WEAKER LLJ ENERGY. THU INTO FRI... AMPLIFIED RIDGE GAINS CONTROL AS LONGWAVE TROF SLIDES OFFSHORE. MAINLY DRY FORECAST EXPECTED. DESPITE THE INITIAL COLD ADVECTION ON THU THE BUILDING RIDGE SHOULD HEIGHTS/MID LVL TEMPS RISING. THEREFORE...LOOKING AT TEMPS NEAR TO SLIGHTLY ABOVE AVERAGE...ESPECIALLY FOR HIGHS GIVEN DECENT LATE APRIL SUN. NEXT WEEKEND... ANOTHER TRANSITIONAL PERIOD AS LONGWAVE TROF APPROACHES FROM THE W. THIS SUGGESTS UNSETTLED AND POTENTIALLY WET CONDITIONS FOR AT LEAST SOME OF THE WEEKEND...BUT WITH A LOT OF VARIABILITY AND MODEL DIFFICULTY RESOLVING AMPLIFIED FLOW BY DAY 7...CONFIDENCE IS LOW IN EXACT TIMING OR HOW WET IT MAY BE. WHILE THERE IS SOME AGREEMENT THAT THE ACTUAL ATTENDANT LOW WOULD BE AN INSIDE RUNNER...HOW FAR NORTH THE CORRIDOR OF STRONGEST DYNAMICS GOES IS DIFFICULT TO RESOLVE. LOOK FOR MORE UPDATES AS WE APPROACH.
-- End Changed Discussion --
&& .AVIATION /19Z SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --
LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...TODAY THROUGH SUNDAY NIGHT...HIGH CONFIDENCE. VFR CONDITIONS. GUSTY NORTHWEST WINDS DIMINISH THIS EVENING. WINDS BECOME ONSHORE LATE TONIGHT...THEN CONTINUE TO SHIFT SOUTHEAST SUNDAY AFTERNOON...THEN SOUTH SUNDAY NIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...MONDAY THROUGH WEDNESDAY... MONDAY INTO TUE...HIGH CONFIDENCE. MAINLY VFR. WINDS SHIFT FROM THE W ON MON TO THE S ON TUE. TUE NIGHT INTO WED...MODERATE CONFIDENCE. VFR GIVES WAY TO MIX OF MVFR/IFR IN PERIODS OF RAIN AND LOW CIGS. CONDITIONS GRADUALLY IMPROVE DURING THE DAY ON WED...ALTHOUGH AS THINGS IMPROVE THERE IS THE CHANCE FOR 25-30 KT W-NW WIND GUSTS ON WED.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH SUNDAY/...HIGH CONFIDENCE. TONIGHT... LOOKS LIKE WE MAY SEE A PERIOD OF NORTH TO NORTHEAST 25 KNOT WIND GUSTS OVER THE EASTERN WATERS IN A SURGE OF COLD ADVECTION. KEPT THE EASTERN ATLANTIC WATERS WITH SMALL CRAFT ADVISORY HEADLINES. ITS POSSIBLE WE MAY NEED TO EXTEND THEM INTO CAPE COD BAY AND NANTUCKET SOUND FOR A TIME. SUNDAY AND SUNDAY NIGHT... WINDS SHOULD REMAIN BELOW ADVISORY THRESHOLDS ACROSS MOST OF THE WATERS. HOWEVER...MARGINAL 5 FOOT SEAS EXPECTED TO LINGER INTO THE LATE MORNING/EARLY AFTERNOON ACROSS PORTIONS OF THE EASTERN ATLANTIC WATERS BEFORE FINALLY SUBSIDING. OUTLOOK...MONDAY THROUGH WEDNESDAY... MONDAY INTO TUE...HIGH CONFIDENCE. HIGH PRES REMAINS IN CONTROL ACROSS THE WATERS. THEREFORE...ASIDE FROM WHAT MAY BE A FEW NEAR SHORE GUSTS APPROACHING 25 KT ON TUE FROM THE S-SW...MAINLY QUIET BOATING WEATHER IS EXPECTED. TUE NIGHT INTO WED...MODERATE CONFIDENCE. COLD FRONT APPROACHES THEN CROSSES THE WATERS EARLY WED WITH PERIODS OF RAIN. TUE NIGHT INTO WED...S WINDS SHOULD REMAIN BELOW SCA THRESHOLDS BUT A BUILDING S SWELL ON THE SRN AND ERN OCEAN WATERS MAY BREAK 5 FT...LEADING TO THE NEED FOR SMALL CRAFT ADVISORIES. ON TUE...ONCE WINDS SHIFT TO THE W-NW WIND GUSTS 25-30 KT AND CONTINUED 5-7 FT SEAS WILL LEAD TO THE NEED FOR SMALL CRAFT ADVISORIES ON ALL WATERS.
-- End Changed Discussion --
&& .FIRE WEATHER...
-- Changed Discussion --
SUNDAY...ALTHOUGH THE DRY WEATHER CONTINUES...WINDS WILL BE MUCH LIGHTER AND HIGH TEMPERATURES A BIT LOWER. NO HEADLINES PLANNED.
-- End Changed Discussion --
&& .HYDROLOGY...
-- Changed Discussion --
MINOR FLOODING CONTINUES ALONG PORTIONS OF THE MAINSTEM CT RIVER. ALL POINTS HAVE FINALLY CRESTED AND ARE NOW RECEDING. SEE THE LATEST FLOOD STATEMENT FOR DETAILS. FLOOD WARNINGS REMAIN POSTED ALONG CT RIVER AT... HARTFORD AND MIDDLE HADDAM
-- End Changed Discussion --
&& .BOX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT SUNDAY FOR ANZ250. SMALL CRAFT ADVISORY UNTIL 5 PM EDT SUNDAY FOR ANZ254. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO NOON EDT SUNDAY FOR ANZ255.
-- End Changed Discussion --
&& $$ SYNOPSIS...BELK/DOODY NEAR TERM...BELK SHORT TERM...BELK LONG TERM...DOODY AVIATION...BELK/DOODY MARINE...BELK/DOODY FIRE WEATHER...BELK HYDROLOGY...BELK

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.