Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 182358 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 758 PM EDT FRI APR 18 2014 .SYNOPSIS... A WEAKENING COLD FRONT WILL MOVE ACROSS SOUTHERN NEW ENGLAND LATER TONIGHT. HIGH PRESSURE WILL THEN BUILD OVER THE REGION BRINGING DRY AND PLEASANT WEATHER SATURDAY THROUGH MONDAY. LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL LIKELY BRING A PERIOD OF WET WEATHER TO THE REGION SOMETIME LATE TUESDAY INTO A GOOD PORTION OF WEDNESDAY. ANOTHER HIGH BUILDS IN WITH DRY... PLEASANT CONDITIONS INTO LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --
750 PM UPDATE... LOW CLOUDS ARE STARTING TO MOVE IN ALONG THE E COAST AS SEEN ON LATEST OBS AT 23Z. ALSO NOTING SOME LOWER VSBYS ACROSS THE OUTER CAPE. E-NE WINDS CONTINUE...BUT HAVE DIMINISHED WHICH HAS HELPED THE LOW CLOUDS TO REDEVELOP AS THE SUN SETS. HAVE ADDED LOWER CLOUDS BACK INTO E MA/RI THROUGH 04Z OR SO. SHOULD SEE CLOUDS BREAK UP AS WINDS SHIFT TO S AHEAD OF APPROACHING FRONT...THEN WILL TEND TO DRY UP AS THE COLD FRONT PASSES AND WINDS SHIFT TO W-NW. PREVIOUS DISCUSSION... TONIGHT...SURFACE COLD FRONT OVER THE GREAT LAKES WILL CROSS NEW ENGLAND OVERNIGHT. EXTRAPOLATION BRINGS THE FRONT TO THE CT VALLEY AROUND 09Z-11Z. JET DYNAMICS ARE FOCUSED TOWARD THE CANADIAN BORDER/NRN VT/NRN NH. TIME CROSS SECTIONS OVER SRN NEW ENGLAND SHOW MOST OF THE FAVORABLE RH AT OR ABOVE 500 MB...BEST RH VALUES OF 60-70 PCT FOR A BRIEF PERIOD AROUND 06Z-09Z. IF THERE ARE ANY SHOWERS IN OUR AREA...WOULD EXPECT THEM TO BE IN SRN NH OR IN EXTREME NRN MASS. WE HAVE ADDED SLIGHT CHANCE POPS TO SRN NH AND EXTREME NORTHERN ESSEX CO BUT VALUES ARE LOW...ROUGHLY 15-18 PCT. TEMPS WILL COOL SOMEWHAT TONIGHT FROM A STARTING POINT IN THE 40S...BUT CLOUDS WILL SLOW ANY COOLING TREND. WE STAYED CLOSE TO A MODEL CONSENSUS WHICH HAS MINS MAINLY IN THE 30S. A FEW OF THE COLDER SPOTS IN FRANKLIN AND CHESHIRE COUNTIES COULD REACH THE UPPER 20S.
-- End Changed Discussion --
&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... SATURDAY... THE COLD FRONT MOVES OFFSHORE SATURDAY MORNING. THE TRAILING UPPER TROUGH CROSSES NEW ENGLAND BETWEEN 12Z AND 18Z. THERE IS SOME CONCERN FOR ADDITIONAL CLOUDS POPPING AS THE COLDEST AIR MOVES OVERHEAD. BUT THE FORECAST MOISTURE CONTENT OF THE AIRMASS DIMINISHES...SO WE WILL FOLLOW MODEL TRENDS AND GO WITH CLEARING SKIES. THE SOLAR HEATING AND COOLING TEMPS ALOFT WILL ALLOW FOR DEEP MIXING OF THE AIRMASS WITH THE MIXED LAYER REACHING TO AT LEAST 900 MB AND PROBABLY TO 850 MB. WINDS IN THIS LAYER TOMORROW WILL REACH AT LEAST 25 KNOTS...AND THERE ARE SOME MODEL INDICATIONS OF 30 KNOTS. THIS WOULD MEAN GUSTS OF 30-35 MPH MIXING TO THE SURFACE TOWARD MIDDAY AND THE AFTERNOON. TEMPS AT 850 MB WILL BE 0C TO -2C...THE NAM SUGGESTS -4C. WITH FULL MIXING THIS WOULD SUPPORT MAX TEMPS IN THE MID 50S TO AROUND 60. THE BUILDING SURFACE PRESSURES SHOULD BE HIGH ENOUGH TO ADD ANOTHER 1-2F TO THESE EXPECTATIONS. WE WILL FORECAST MID 50S TO LOWER 60S. SATURDAY NIGHT... HIGH PRESSURE IN QUEBEC BUILDS OVER NEW ENGLAND. EXPECT CLEAR SKIES AND LIGHT WINDS WITH DEWPOINTS IN THE 20S AND LOWER 30S. RADIATIONAL COOLING SHOULD ALLOW MIN TEMPS IN THE UPPER 20S AND 30S. && .LONG TERM /SUNDAY THROUGH FRIDAY/... HIGHLIGHTS... * DRY SUNDAY AND MONDAY WITH CHILLY NIGHTS AND MILD DAYS * WET WEATHER LIKELY SOMETIME LATE TUESDAY INTO MOST OF THE DAY WEDNESDAY * ANOTHER HIGH BRINGS DRY AND SEASONABLE CONDITIONS INTO LATE NEXT WEEK OVERVIEW AND MODEL PREFERENCES/CONFIDENCE... MEDIUM RANGE MODELS AND ENSEMBLES CONTINUE TO SIGNAL CHANGING CONDITIONS DURING THIS TIMEFRAME...FROM A RATHER FLAT...SPLIT FLOW PATTERN EARLY TO A DEVELOPING AMPLIFIED...SLOWLY PROGRESSIVE PATTERN BY THE MIDDLE TO END OF NEXT WEEK. QUESTION AS TO WHETHER THIS SLOWING IN THE UPPER LEVELS WILL TRANSLATE TO THE SURFACE... CAUSING APPROACHING FRONTAL SYSTEM DURING TUE INTO WED TO SLOW AS IT MOVES OFF THE COAST. OPERATIONAL MODEL RUNS SHOWING QUITE A BIT OF SPREAD BEYOND WEDNESDAY AS THE NEXT SYSTEM THAT TRIES TO SHIFT E OUT OF THE GREAT LAKES WITH...OF ALL MODELS...THE 12Z EC TRYING TO KEEP THE NEXT SYSTEM MOVING FASTER WHILE THE GFS SLOWS THE RIDGE ACROSS THE REGION THROUGH FRIDAY. USED A BLEND OF THE GFS/EC ENSEMBLES ALONG WITH THE PREVIOUS FORECAST...GIVING GOOD CONSISTENCY. THIS WAS ALSO PRETTY CLOSE TO THE WPC GUIDANCE. HAVE OVERALL MODERATE FORECAST CONFIDENCE SUNDAY INTO WEDNESDAY...THEN LOWER CONFIDENCE LATE NEXT WEEK. DETAILS... SUNDAY AND SUNDAY NIGHT... LARGE HIGH PRES WILL BUILD ACROSS QUEBEC DURING LATE SUNDAY INTO MONDAY. SKIES WILL START OUT MOSTLY CLEAR EARLY SUNDAY MORNING...THEN SOME CLOUDS WILL DEVELOP ESPECIALLY ALONG THE COAST AS EAST TO NORTHEAST WINDS WILL BRING COOLER CONDITIONS. EXPECT HIGHS FROM ONLY AROUND 50 ALONG THE IMMEDIATE COAST...RANGING TO THE MID 50S TO NEAR 60 ACROSS THE CONNECTICUT RIVER VALLEY. OCEAN CLOUDS MAY MOVE INLAND DURING SUNDAY NIGHT WITH THE ONSHORE WINDS AS THE HIGH SHIFTS ACROSS THE GULF OF MAINE TO E OF NEW ENGLAND. EXPECT GENERALLY LIGHT WINDS THAT WILL BEGIN TO SHIFT TO SE TO S OVERNIGHT. MAY ALSO SEE SOME PATCHY FOG DEVELOP ALONG THE SHORE AFTER MIDNIGHT. WITH LIGHT WINDS...TEMPS WILL FALL BACK TO THE 30S AT MOST LOCATIONS...THOUGH MAY HOLD NEAR 40 ALONG THE IMMEDIATE COAST. SOME QUESTION AS TO THE TEMP REGIME...DEPENDING UPON HOW MUCH CLOUDINESS WORKS INLAND. MONDAY... HIGH PRES REMAINS IN CONTROL E OF THE REGION...THOUGH THE RIDGE TENDS TO WEAKEN DURING THE DAY. SKIES WILL BE MAINLY MOSTLY SUNNY...THOUGH A FEW CLOUDS MIGHT LINGER ALONG THE COAST EARLY. EXPECT WINDS TO BECOME MORE SOUTHERLY DURING THE DAY BUT WILL REMAIN AT 10 MPH OR LESS. WITH THE LIGHT PRES GRADIENT ACROSS THE REGION AND H85 TEMPS RISING TO +6C TO +9C DURING THE DAY AS THE S WINDS TAKE HOLD...WILL SEE TEMPS RISE TO THE MID AND UPPER 60S WELL INLAND. BIG QUESTION WILL BE WHETHER SEA BREEZES DEVELOP ALONG THE COAST...WHICH COULD KEEP TEMPS BACK IN THE 50S. IF THEY DO DEVELOP...MAY BE RATHER SHALLOW AND REMAIN WITHIN A FEW MILES OF THE SHORELINE. ON MONDAY NIGHT...MID AND HIGH LEVEL CLOUDS WILL INCREASE AHEAD OF APPROACHING SYSTEM OUT OF THE GREAT LAKES. OVERNIGHT LOWS WILL ONLY BE IN THE 40S. TUESDAY AND WEDNESDAY... MODELS CONTINUE TO SIGNAL A RATHER STRONG H5 SHORT WAVE WORKING E OUT OF THE GREAT LAKES INTO NORTHERN NEW ENGLAND LATER TUESDAY. ASSOCIATED COLD FRONT WILL BRING ROUND OF SHOWERS ACROSS THE REGION...THOUGH TIMING IS STILL A BIT UNCERTAIN. FOR NOW...LOOKS LIKE BEST SHOT FOR PRECIP WILL BE FROM TUESDAY NIGHT THROUGH MOST OF THE DAY ON WEDNESDAY. ANOTHER QUESTION WILL BE WHETHER THE SYSTEM SLOWS DOWN AS IT MOVES INTO THE REGION ON WEDNESDAY. MODELS STILL SHOWING SOME SOLUTION SPREAD WITH THIS ASPECT...THOUGH DOES LOOK LIKE IT SHOULD PUSH OFFSHORE EARLY WEDNESDAY NIGHT. THURSDAY AND FRIDAY... ANOTHER HIGH RIDGE WILL LOOKS TO BUILD DOWN THE EASTERN SEABOARD DURING THURSDAY...WITH ANOTHER SHOT OF DRY BUT COOLER AIR. SOME MODELS TRY TO KEEP SOME SPOTTY PRECIP ALONG THE COAST EARLY THU. LOOKS TO BE MAINLY DRY ON FRIDAY AS THE RIDGE SLOWLY PUSHES OFFSHORE...THOUGH A WARM FRONT MAY BRING A FEW WIDELY SCT SHOWERS LATE IN THE DAY OR FRI NIGHT. TIMING REMAINS UNCERTAIN THOUGH. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. MODERATE CONFIDENCE TONIGHT...HIGHER CONFIDENCE SATURDAY AND SATURDAY NIGHT... EARLY TONIGHT...MODERATE CONFIDENCE...MAINLY FOR TIMING. MVFR-IFR CIGS/LOCAL MVFR VSBYS IN LOW CLOUDS AND PATCHY FOG REDEVELOP ALONG E COAST THROUGH AROUND 04Z-05Z...THEN SHOULD DISSIPATE AS WINDS SHIFT TO S AHEAD OF APPROACHING FRONT. LATER TONIGHT...HIGH CONFIDENCE IN TREND...MODERATE CONFIDENCE IN TIMING. EXPECT WINDS TO SHIFT AS A COLD FRONT FROM THE GREAT LAKES APPROACHES. THIS SHOULD MOVE THE LOWER CLOUDS OUT OF THE AREA WHILE VFR CLOUDS ASSOCIATED WITH THE FRONT MOVE IN. MOVEMENT OF THE FRONT WOULD BRING IT THROUGH OUR AREA BETWEEN 06Z AND 12Z. CONDITIONS SHOULD REMAIN VFR THROUGH THE NIGHT WITH WINDS SHIFTING TO NORTHWEST LATE. SATURDAY AND SATURDAY NIGHT... DRIER AIR MOVES IN. EXPECT CLEARING SKIES AND VFR. DAYTIME HEATING BY THE SUN WILL DRAW STRONGER WINDS GUSTS TO THE SURFACE WITH GUSTS TO AT LEAST 25 KNOTS...POSSIBLY 30 KNOTS. THESE WINDS WILL DIMINISH AROUND SUNSET. CONTINUED VFR WITH DIMINISHING NORTH WIND SATURDAY NIGHT. KBOS TERMINAL...MODERATE CONFIDENCE. MAIN ISSUE IS EXTENT AND DURATION OF MVFR CIGS THROUGH EARLY TONIGHT. KBDL TERMINAL...HIGH CONFIDENCE. OUTLOOK...SUNDAY THROUGH WEDNESDAY... SUNDAY-MONDAY...HIGH CONFIDENCE. VFR CONDITIONS. TUESDAY AND WEDNESDAY...LOW TO MODERATE CONFIDENCE. VFR CONDITIONS TO START ON TUESDAY. CIGS/VSBYS MAY LOWER TO MVFR IN SCT SHOWERS AND PATCHY FOG LATE TUESDAY THROUGH AT LEAST MIDDAY WEDNESDAY. CONDITIONS SHOULD IMPROVE TO VFR FROM W-E WEDNESDAY AFTERNOON AND EVENING.
-- End Changed Discussion --
&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE. WINDS MOST OF THE TIME WILL REMAIN BELOW 25 KNOTS. IT IS POSSIBLE ON SATURDAY THAT GUSTS CLOSE TO SHORE MAY BE NEAR 25 KNOTS. WINDS WILL SHIFT TO NORTHWEST ON SATURDAY AND NORTH SATURDAY NIGHT. A LINGERING SWELL WILL KEEP SEAS 5 TO 7 FEET THROUGH SATURDAY...AND 5 FOOT SEAS MAY LINGER ON THE OUTER WATERS SATURDAY NIGHT. WILL CONTINUE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS ON THE OUTER WATERS AND ON MASSACHUSETTS BAY/IPSWICH BAY. OUTLOOK...SUNDAY THROUGH WEDNESDAY... SUNDAY...MODERATE TO HIGH CONFIDENCE. EXPECT NE WINDS TO GUST UP TO 20 KT EARLY...THEN WILL DIMINISH DURING THE DAY AS THEY SHIFT TO E AS THE HIGH STARTS TO SHIFT OFFSHORE LATE SUN AFTERNOON/SUN NIGHT. LEFTOVER 5 FOOT SEAS ACROSS THE SOUTHERN OUTER WATERS SHOULD SUBSIDE. MONDAY AND TUESDAY...MODERATE TO HIGH CONFIDENCE. EXPECT LIGHT SE WINDS ON MONDAY TO BECOME S MON NIGHT AND TUE. SEAS REMAIN BELOW SMALL CRAFT CRITERIA. TUESDAY NIGHT AND WEDNESDAY...MODERATE CONFIDENCE. SW WINDS TUE NIGHT WILL SHIFT TO W AS LOW PRES AND COLD FRONT MOVE SLOWLY ACROSS THE WATERS. EXPECT NW WINDS TO PICK UP DURING WED...THOUGH TIMING IS UNCERTAIN. COULD SEE LOW END SMALL CRAFT WINDS AND SEAS LATE WED OR WED NIGHT ACROSS THE OPEN WATERS. && .FIRE WEATHER... WEATHER CONDITIONS DRY OUT DURING THE DAY SATURDAY WITH DEWPOINTS IN THE 20S AND MINIMUM RH VALUES REACHING 28-35 PERCENT. NORTHWEST WINDS ARE ALSO EXPECTED TO PICK UP WITH GUSTS OF AT LEAST 25 KNOTS AND POSSIBLY 30 KNOTS. WEATHER CONDITIONS ARE SUFFICIENT TO CREATE AN ELEVATED FIRE WEATHER CONCERN...BUT REPORTS RECEIVED SO FAR INDICATE GROUND CONDITIONS ARE STILL TOO MOIST. NO FIRE WEATHER HEADLINES WILL BE ISSUED AT THIS TIME...BUT THE SITUATION WILL BE MONITORED. && .HYDROLOGY... MINOR FLOODING CONTINUES ALONG PORTIONS OF THE MAIN STEM CT RIVER. MOST POINTS HAVE CRESTED AND ARE NOW RECEDING...MIDDLE HADDAM WILL CREST TONIGHT. SEE THE LATEST FLOOD STATEMENT FOR DETAILS. FLOOD WARNINGS REMAIN POSTED ALONG CT RIVER AT... NORTHAMPTON THOMPSONVILLE HARTFORD MIDDLE HADDAM && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM EDT SUNDAY FOR ANZ250-254. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM EDT SATURDAY FOR ANZ251. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 1 PM EDT SATURDAY FOR ANZ255-256. && $$ SYNOPSIS...WTB/EVT NEAR TERM...WTB/EVT SHORT TERM...WTB LONG TERM...EVT AVIATION...WTB/EVT MARINE...WTB/EVT FIRE WEATHER...WTB HYDROLOGY...WTB

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