Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 231856 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 256 PM EDT THU APR 23 2015 .SYNOPSIS... UNSEASONABLY COOL WEATHER CONTINUES INTO AT LEAST EARLY NEXT WEEK WITH SPOTTY SHOWERS OR SPRINKLES. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... THROUGH EVENING...CLOSED UPPER LOW AND COLD POOL ARE IN POSITION OVER NEW ENGLAND. THE COLD POOL IS PROVIDING AN UNSTABLE PROFILE THAT HAS GENERATED SOME LIGHT SHOWERS ALONG WITH A COUPLE OF REPORTS OF GRAUPEL. ALSO IN THE MIX IS A SHORTWAVE MOVING THROUGH THE CYCLONIC FLOW. THIS GENERATED TWO OR MORE LINES OF SHOWERS AS IT MOVED ACROSS NEW YORK...AND WILL MOVE ACROSS SOUTHERN NEW ENGLAND LATE AFTERNOON/EVENING. AXIS IS ACROSS CAPE COD AND THE ISLANDS AROUND 8 PM. WE HAVE BUMPED POPS UP ESPECIALLY IN WESTERN AND CENTRAL MASS AND NORTHERN CT DUE TO THE APPROACHING SHORTWAVE. GUSTY WEST WINDS CONTINUE THROUGH THE EVENING AND THEN DIMINISH. TONIGHT... COLD AIR SURFACE AND ALOFT REMAINS IN PLACE. CROSS SECTIONS SHOW PLENTY OF MOISTURE LINGERING BETWEEN 850 AND 700 MB...AS WELL AS SOME LIFT IN THIS LAYER. EXPECT CLOUDS DIMINISHING AFTER SUNSET BUT NOT COMPLETELY GOING AWAY. WEST WINDS WILL BRING AIR IN FROM THE GREAT LAKES. MIN TEMPS UPSTREAM THIS MORNING WERE IN THE UPPER 20S TO MID 30S. CLOUDS AND LINGERING WIND WILL INTERFERE WITH FROST DEVELOPMENT OUTSIDE OF ANY STRONGLY SHELTERED SPOTS. BUT AIR TEMPS AT OR A LITTLE BELOW 32F ARE EXPECTED IN WESTERN PARTS OF THE AREA. MEANWHILE THE FROST/FREEZE SEASON HAS STARTED IN CT-RI AS WELL AS IN SOUTHEAST AND COASTAL MASS. FREEZING TEMPS ARE EXPECTED IN AT LEAST 50% OF NORTHCENTRAL AND NORTHEAST CT. FREEZING TEMPS ARE POSSIBLE IN PARTS OF NORTHWEST RI. EXPECTED COVERAGE IS LESS IN SOUTHEAST AND COASTAL MASS. WE WILL ISSUE A FREEZE WARNING FOR HARTFORD-TOLLAND-WINDHAM COUNTIES IN CT AND WESTERN PROVIDENCE- WESTERN KENT COUNTIES IN RI FOR LATE TONIGHT/FRIDAY MORNING. IN THE RI PORTION...OUR EXPECTATION IS MOSTLY TO THE WEST AND NORTHWEST OF THE SCITUATE RESERVOIR. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FRIDAY...WILL LIKELY SEE ANOTHER ROUND OF DIURNAL CLOUDS DEVELOP. SHOWER/SPRINKLE COVERAGE SHOULD BE LESS THAN TODAY. IT/S STILL UNSTABLE ALOFT BUT LACKING THE PASSAGE OF THE SHORTWAVE TO ORGANIZE CONVECTION. THE MIXED LAYER REACHES NEAR 800 MB AGAIN WITH 20-25 KNOT WINDS IN THE LAYER. TEMPS NEAR THE TOP OF THE LAYER WILL BE SIMILAR TO TODAY AND SO WE EXPECT MAX SFC TEMPS EITHER SIDE OF 50...PERHAPS MID 50S IN THE WARMEST SPOTS. FRIDAY NIGHT... UPPER LOW SHIFTS EAST BUT COLD POOL AND CLOUD MOISTURE LINGERS OVER NEW ENGLAND. SO WE MAY NOT CLEAR COMPLETELY...BUT PROBABLY FEWER CLOUDS THAN TONIGHT. TEMPERATURES SHOULD BE SIMILAR TO TONIGHT BUT MODEL GUIDENCE IS A DEGREE OR TWO LESS COLD. THIS LEAVES LESS ROOM FOR ANY ADDITIONAL FREEZE HEADLINES IN CT. THIS STATUS WILL BE REEVALUATED BY THE MIDNIGHT SHIFT. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... HIGHLIGHTS... * BELOW NORMAL TEMPERATURES THROUGH NEXT WEEK * SPOTTY DIURNAL SHOWERS THIS WEEKEND INTO MID-NEXT WEEK * LOW CONFIDENCE ON COASTAL SYSTEM THURS/FRIDAY. OVERVIEW... OVERALL THE 00Z MODELS HANDLE THE DEEP CLOSED LOW MOVING ACROSS THE NORTHEAST COMPARABLY ON FRI AND GRADUALLY SHIFT THE ENERGY OFFSHORE SOUTHEAST CANADA ON SAT INTO SUNDAY. A GENERAL MODEL COMPROMISE IS PREFERRED FOR THIS TIME PERIOD. BEYOND THE WEEKEND THE FOCUS IS ON THE UPPER LEVEL LOW...WHICH WILL MIGRATE BACK TOWARDS THE NORTHEAST BY MONDAY...AND A CLOSED LOW OVER THE DESERT SOUTHWEST. THE FORECAST CHALLENGE FOR NEXT WEEK WILL BE THE MIGRATION OF THIS DESERT LOW ACROSS THE SOUTHERN PLAINS AND ITS INTENSIFICATION ACROSS THE SOUTHEAST AS IT WRAPS UP INTO THE CLOSED LOW. A KEY COMPONENT OF THE SYSTEM`S INTENSIFICATION WILL BE THE INCORPORATION OF SOUTHEASTWARD-MOVING SHORTWAVE ENERGY AND WHERE THIS NORTHERN STREAM ENERGY WILL PHASE WITH THE CUTOFF SYSTEM. CURRENTLY THE 00Z GFS IS FASTER AND PHASES OVER THE PLAINS WHERE THE EC IS LESS AMPLIFIED/MORE PROGRESSIVE AND ALLOWS THE ENERGY TO BE THE KICKER TO PUSH THE CUTOFF LOW OUT TO SEA. TELECONNECTION INDICES OF -NAO/+PNA DO NOT TRULY SUPPORT THE EC SOLUTION...SO TRENDED CLOSER TO WPC AND THE GFS FOR THIS FORECAST. DETAILS... * SATURDAY INTO SUNDAY...HIGH CONFIDENCE. STRONG CUTOFF LOW WILL CONTINUE TO IMPACT THE NORTHEAST DURING THIS TIME PERIOD. UPPER LEVEL RIDGE OVER THE CENTER CONUS WILL BUILD PUSHING THE BULK OF THE ENERGY OFFSHORE SAT/SUN. THIS MAY LIMIT SHOWER CHANCES AS BEST COLD POOL AND FORCING WILL BE NORTHEAST OF THE AREA. A STRENGTHENED SURFACE LOW WILL PASS SOUTH OVER THE MID- ATLANTIC DURING THIS TIME PERIOD KEEPING MOST OF THE MOISTURE TO THE SOUTH. REGARDLESS APPEARS THAT THIS SURFACE LOW WILL GET CAUGHT IN THE OVERALL UPPER FLOW PATTERN AND RETROGRADE THE LOW BACK TOWARDS NEW ENGLAND BY EARLY NEXT WEEK. THIS LOW AND ITS ASSOCIATED COLD POOL WILL CONTINUE TO KEEP TEMPS BELOW AVERAGE FOR MUCH OF THE FORECAST. A FEW SITES MAY WARM INTO THE 60S OVER THE WEEKEND AS THE COLD POOL WILL BE EAST OF THE AREA. ANTICIPATE CLEARING SKIES OVERNIGHT WITH DIURNAL CU DURING THE DAY. STILL CANT RULE OUT AN ISOLATED SHOWER DURING THE AFTERNOON HOURS...BUT NOTHING TO CANCEL WEEKEND PLANS OVER. AREAS THAT HAVE THE BEST CHANCE FOR ANY PRECIP WILL BE THE NORTHEAST HALF OF THE REGION...CLOSER TO THE LOW PRESSURE. * MONDAY INTO TUESDAY...MODERATE CONFIDENCE. GUIDANCE BEGINS TO SPLIT THE UPPER LEVEL PATTERN OUT WEST DURING THIS PORTION OF THE FORECAST AS MENTIONED ABOVE. FOR NEW ENGLAND...THE UPPER LEVEL LOW WILL RETROGRADE INCREASING THE CHANCES OF PRECIP AS SEVERAL POTENT SHORTWAVES MORE THROUGH THE FLOW. CHANCE FOR SHOWERS WILL BE HIGHER THAN FOR THIS UPCOMING WEEKEND. TEMPERATURES WILL CONTINUE TO BE COOLER THAN NORMAL. WEDNESDAY AND BEYOND...LOW CONFIDENCE. LOTS OF UNCERTAINTY IN THIS PORTION OF THE FORECAST. EVERYTHING IS DEPENDENT ON HOW THE CUT-OFF LOW IN THE DESERT SOUTHWEST BEHAVES. CURRENTLY BELIEVE WED IS A TRANSITION DAY WITH BELOW NORMAL TEMPS CONTINUING. WATCHING THE DEVELOPMENT OF A COASTAL LOW ON THURSDAY PER THE GFS...WHERE THE 00Z EC SEEMS TO LOST THE LOW VS ITS 12Z COUNTERPART. REGARDLESS BELIEVE BELOW AVG TEMPS WILL CONTINUE. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM /THROUGH FRIDAY NIGHT/... THROUGH 8 PM/00Z...HIGH CONFIDENCE. VFR WITH PATCHES OF MVFR CIGS/VSBYS IN SHOWERS ESPECIALLY WORCESTER HILLS AND POINTS WEST. GUSTY WEST WINDS 20-25 KNOTS DIMINISHING TOWARD SUNSET. TONIGHT...HIGH CONFIDENCE. VFR. FRIDAY...HIGH CONFIDENCE. MAINLY VFR. AS WITH TODAY...CONDITIONS MAY BRIEFLY LOWER TO MVFR IN LIGHT SHOWERS FROM MIDDAY THROUGH THE EARLY EVENING HOURS. WEST WINDS GUSTING TO 20 KNOTS DURING THE DAY. FRIDAY NIGHT...HIGH CONFIDENCE. VFR. KBOS TAF...HIGH CONFIDENCE IN OVERALL TAF. MODERATE CONFIDENCE IN TIMING OF SHOWERS. KBDL TAF...HIGH CONFIDENCE IN OVERALL TAF. MODERATE CONFIDENCE IN TIMING OF SHOWERS. OUTLOOK...SATURDAY THOUGH MONDAY... SAT AND SUNDAY...HIGH CONFIDENCE. MAINLY VFR. CONDITIONS COULD LOWER TO MVFR QUICKLY IN A BRIEF DIURNALLY DRIVEN SHOWER OR TWO. SEA BREEZE DEVELOPMENT IS POSSIBLE ALONG THE EAST COAST. MONDAY...MODERATE CONFIDENCE. VFR WITH MVFR CONDITIONS IN SCT SHOWERS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... TONIGHT...HIGH CONFIDENCE. A WEAK FRONT SWEEPS ACROSS THE WATERS. WEST WINDS GUSTING NEAR 25 KNOTS EARLY AND 15-20 KNOTS LATE. SEAS AT 5-7 FEET ON THE OUTER WATERS AND RI WATERS WILL DIMINISH OVERNIGHT. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL WATERS THIS EVENING AND MOST WATERS OVERNIGHT. FRIDAY...HIGH CONFIDENCE. WEST-NORTHWEST WINDS WILL GUST TO 20 KNOTS. A FEW SPOTS MAY APPROACH 25 KNOTS...PRIMARILY SOUTH OF BLOCK ISLAND. SEAS LINGER AT 5 FEET ON THE SOUTHERN AND SOUTHEAST OUTER WATERS. A SMALL CRAFT ADVISORY WILL CONTINUE MAINLY ON THOSE OUTER WATERS. FRIDAY NIGHT...HIGH CONFIDENCE. WEST-NORTHWEST WINDS WILL CONTINUE TO GUST NEAR 20 KNOTS. SEAS WILL LINGER BETWEEN 4-5 FEET. OUTLOOK...SATURDAY THOUGH MONDAY... SATURDAY INTO MONDAY...HIGH CONFIDENCE. UPPER LEVEL LOW WILL CONTINUE TO SPIN ACROSS THE NORTHEAST. HIT OR MISS SHOWERS POSSIBLE DURING EACH DAY. HOWEVER EXPECTING BOTH WIND AND SEAS TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. && .HYDROLOGY... A COMBINATION OF RAINFALL AND SNOWMELT ACROSS NORTHERN NEW ENGLAND WAS MAKING ITS WAY DOWN THE CONNECTICUT RIVER. THIS COMBINED WITH TIDAL INFLUENCES AT THE MOUTH OF THE RIVER WILL RESULT IN MINOR FLOODING ACROSS PORTIONS OF THE LOWER CONNECTICUT RIVER. THE RIVER NEAR MIDDLE HADDAM IS UNDER STRONG TIDAL INFLUENCE. AS A RESULT...THE RIVER IS ABOVE FLOOD STAGE AT HIGH TIDE AND NEAR FLOOD STAGE AT LOW TIDE. THIS IS EXPECTED TO TREND LOWER THE NEXT COUPLE OF CYCLES...WITH A HIGH TIDE CREST BELOW FLOOD STAGE LATE FRIDAY AFTERNOON. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...FREEZE WARNING FROM 3 AM TO 8 AM EDT FRIDAY FOR CTZ002>004. MA...NONE. RI...FREEZE WARNING FROM 3 AM TO 8 AM EDT FRIDAY FOR RIZ001-003. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230- 236. SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL NOON EDT FRIDAY FOR ANZ250-251- 254>256.
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&& $$ SYNOPSIS...WTB/DUNTEN NEAR TERM...WTB SHORT TERM...WTB LONG TERM...DUNTEN AVIATION...WTB/DUNTEN MARINE...WTB/DUNTEN HYDROLOGY...

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