Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 302304 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 704 PM EDT THU APR 30 2015 .SYNOPSIS... CONTINUED MID- TO UPPER-LEVEL DISTURBANCES WILL RESULT IN CLOUDS AND A FEW SHOWERS AROUND THROUGH THE END OF THE WEEK. MAINLY DRY CONDITIONS ARE EXPECTED THROUGH THE WEEKEND...BUT A SERIES OF WEAK DISTURBANCES MAY BRING A FEW SHOWERS FROM TIME TO TIME. WARMER TEMPERATURES ARRIVE SUNDAY INTO EARLY NEXT WEEK...BUT A BACKDOOR FRONT WILL BRING SHOWERS TUESDAY FOLLOWED BY DRY AND MILD WEATHER WEDNESDAY AND THURSDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 7 PM UPDATE... CLOUDS HAVE FILLED IN ACROSS THE REGION AND NOTING A FEW SHOWERS MOVING S ACROSS NH. CLOUDY SKIES WILL PREVAIL TONIGHT AND CANT RULE OUT A BRIEF SHOWER AS BACKDOOR FRONT SETTLES S. UPDATED T/TD/POP GRIDS FOR NEAR TERM TRENDS. OTHERWISE FORECAST ON TRACK. PREVIOUS DISCUSSION... LIGHT SHOWERS / SPRINKLES PREVAIL AHEAD OF A BACKDOOR COLD FRONT SWEEPING S/SW ACROSS THE REGION OVERNIGHT. FORECAST GUIDANCE STILL POORLY HANDLING THE LIGHT EVENT. WILL FOCUS ON WHERE FORECAST GUIDANCE CONSENSUS IS DERIVING BROKEN TO OVERCAST CLOUDS. SLIGHT CHANCE POPS. DO HAVE HIGHER CONFIDENCE OF OUTCOMES CONSIDERING ASCENT OF AVAILABLE MOISTURE AHEAD OF THE FRONT THROUGH A FAVORABLE ENVIRONMENT ALOFT. UPSTREAM BANDING OF SHOWERS AND COLDER CLOUD TOPS HAS BEEN EVIDENT ACROSS MAINE PER SATELLITE AND RADAR. BELIEVE THE GREATER FOCUS OF ACTIVITY WILL BE ALONG NE- SLOPES OF HIGHER TERRAIN WITH OROGRAPHIC TENDENCIES AS SOME OF THE NEAR-TERM HIGH- RES GUIDANCE SUGGESTS. E-ONSHORE FLOW AHEAD OF THE FRONT BACKING NW WITH PASSAGE BECOMING BLUSTERY WITH GUSTS AROUND 20-25 MPH POSSIBLE. COOL AIRMASS OFF THE OCEAN MAINTAINED...BUT ALSO A PRONOUNCED CLOUD DECK. LOWS AROUND THE LOW- TO MID-40S. BELIEVE BLANKETING CLOUDS WILL PREVENT LOCALES FROM FALLING INTO THE UPPER-30S AS WAS THE CASE LAST NIGHT. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... FRIDAY... WILL KEEP THE FOCUS OF LIGHT SHOWERS/SPRINKLE ACTIVITY ACROSS SW- AREAS OF NEW ENGLAND AHEAD OF THE BACKDOOR COLD FRONT AS IT SLIDES S AND BECOMES DIFFUSE UP AGAINST A PRONOUNCED OFFSHORE LOW DEVELOPS OFF THE MID-ATLANTIC COAST. HIGH PRESSURE OVER THE GULF OF MAINE BUILDS INTO THE REGION. CLOUDS DISSIPATING E TO W EVER SLOWLY. A LIGHT WIND PROFILE...AS WELL AS A COLDER AIRMASS IN PLACE ALOFT...SHOULD MAKE FOR AN UNSEASONABLY COOL DAY. LOOKING AT HIGHS IN THE 50S ACROSS THE INTERIOR...COOLER WITH ONSHORE SEA-BREEZE FLOW ACROSS E MA. FRIDAY NIGHT... AS THE OFFSHORE LOW DEEPENS...N-STREAM MID-LEVEL ENERGY IS USURPED ACROSS THE REGION REARWARD INTO THE POSITIVELY-TILTED TROUGH. MID- LEVEL CLOUD DECKS NOT OUT OF THE QUESTION...BUT SOME THOUGHT AS TO WHETHER WE WILL SEE ONE LAST SHOT OF SPRINKLE ACTIVITY BEFORE WE CLEAR OUT. MOISTURE DOES BECOME FOCUSED AHEAD OF THE WAVE AND THERE IS FAVORABILITY WITH RESPECT TO THE LOCAL ENVIRONMENT SUPPORTIVE FOR LIFT...ALBEIT MID-LEVEL ENERGY IS STRETCHED BECOMING WEAKER. WILL GO WITH SLIGHT CHANCE POPS FOR SPRINKLE ACTIVITY COINCIDENT WITH BROKEN TO OVERCAST CLOUD DECKS. SOME HINT WITH LONG-FETCH OF NE-FLOW OFF THE WATERS THAT MOISTURE- LOADING OCCURS BECOMING TRAPPED BENEATH THE DRY INVERSION ASSOCIATED WITH THE HIGH PRESSURE OVER THE GULF OF MAINE. COULD SEE A MIX OF LOW CLOUDS / FOG / DRIZZLE OVER E/SE NEW ENGLAND. NOT ALL FORECAST GUIDANCE IS ON BOARD...BUT IT IS SOMETHING WORTH MONITORING. WILL NOT PREVAIL WITH THIS FORECAST DUE TO UNCERTAINTY. OTHERWISE LIGHT WINDS WITH NE-FLOW ALONG THE SHORES OVERNIGHT. CLOUD DECKS LENDING TO A BLANKET EFFECT...BUT SHOULD ANY LOCALES CLEAR OUT WOULD EXPECT RADIATIONAL COOLING. LOWS AROUND THE UPPER-30S WITH COOLER TEMPERATURES DURING THE DAY AND EXPECTATION OF RADIATIONAL COOLING OVERNIGHT. && .LONG TERM /SATURDAY THROUGH THURSDAY/... HIGHLIGHTS... * A SPOT SHOWER POSSIBLE THIS WEEKEND...OTHERWISE DRY WEATHER AND MILDER SUNDAY * EVEN WARMER EARLY NEXT WEEK BUT A CHANCE OF SHOWERS TUE * DRY AND MILD WED/THU OVERVIEW... UPPER TROF LIFTS OUT SATURDAY FOLLOWED BY WEAK RIDGING AND RISING HEIGHTS INTO EARLY NEXT WEEK WHICH WILL LEAD TO A WARMING TREND. HOWEVER...POLAR JET JUST TO THE NORTH WITH SHORTWAVE ENERGY MOVING THROUGH WILL BREAK DOWN THE RIDGE RESULTING IN A BACKDOOR FRONT SOMETIME TUE OR TUE NIGHT AS MID LEVEL FLOW TURNS NW. SATURDAY AND SUNDAY... WEAK SFC RIDGING ON SAT WILL ALLOW FOR AT LEAST PTSUNNY SKIES. WEAK SHORTWAVE PASSAGE COUPLED WITH TT RISING INTO THE UPPER 40S MAY TRIGGER AN ISOLD SHOWER...MAINLY WESTERN NEW ENG OTHERWISE DRY WEATHER. ANOTHER WEAK SHORTWAVE PASSAGE SUNDAY WITH TT A BIT HIGHER...IN THE LOWER 50S AND SFC LI DROPPING TO NEAR ZERO BUT LOW LEVEL MOISTURE IS A BIT LESS SO WORST CASE WOULD BE ANOTHER CHC OF AN ISOLD SHOWER/TSTM...OTHERWISE PT-MOSUNNY SKIES. COVERAGE LIMITED AND ONLY HAVE SLIGHT CHC POPS IN THE GRIDS. ONSHORE FLOW SAT WITH DEVELOPING SEABREEZES WILL KEEP TEMPS ALONG THE COAST IN THE 50S...WITH LOW TO MID 60S ELSEWHERE. WARMEST SPOT WILL BE IN THE CT VALLEY WHERE A FEW LOCATIONS MAY APPROACH 70 DEGREES. ON SUNDAY...LOW LEVEL FLOW BECOMES WESTERLY WITH 925 MB TEMPS WARMING TO 13-14C. MAXES SHOULD REACH INTO THE LOWER 70S INTERIOR VALLEYS WITH MID/UPPER 60S ELSEWHERE...COOLER CAPE/ISLANDS AND IMMEDIATE S COAST. MONDAY AND TUESDAY... INCREASING SW FLOW AHEAD OF COLD FRONT WILL BRING 850 MB TEMPS TO 10- 11C ON MON WITH HIGH REACHING WELL INTO THE 70S IN THE INTERIOR AND POSSIBLY NEAR 80 CT VALLEY. COOLER 60S ALONG THE S COAST. MODELS BRING A BACKDOOR FRONT SWD INTO SNE SOMETIME TUE OR TUE NIGHT WHICH WILL BE ACCOMPANIED BY SOME SHOWERS...BUT TIMING STILL UNCERTAIN THIS FAR OUT. DEPENDING ON TIMING OF FRONT AND CLOUD COVER/SHOWERS... ANOTHER WARM DAY IS POSSIBLE BUT CONFIDENCE IN TEMPS IS LOWER AND IT COULD END UP CONSIDERABLY COOLER THAN FORECAST IS FRONT IS QUICKER. WEDNESDAY AND THURSDAY... IT APPEARS ANY SHOWERS WILL PUSH TO THE S BY WED...WITH HIGH PRESSURE BUILDING IN BRINGING DRY WEATHER AND MILD TO WARM TEMPS. && .AVIATION /23Z 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/... TONIGHT...HIGH CONFIDENCE. COLD FRONT DROPS S. WINDS BECOMING NE. GUSTS UP TO 20 KTS POSSIBLE BEHIND THE FRONT. BRIEF -SHRA POSSIBLE. LOW-END VFR CIGS DROPPING TO MVFR OVERNIGHT. FRIDAY...HIGH CONFIDENCE. CONTINUED ONSHORE FLOW. WINDS RELAXING AS THEY TURN E. LOW-END VFR / MVFR CIGS LIFTING DURING THE MID-MORNING TO MIDDAY HOURS. -SHRA CHANCES DIMINISH. FRIDAY NIGHT...MODERATE CONFIDENCE. LOW-END VFR CIGS POSSIBLE ALONG WITH ANOTHER SHOT OF -SHRA. WINDS TURNING N. MAY SEE IFR CIGS AND DRIZZLE ACROSS E/SE-COASTAL TERMINALS WITH THE ONSHORE FLOW. VSBY ISSUES WITH FOG POSSIBLE. KBOS TAF...HIGH CONFIDENCE IN TAF. SHOULD SEE A MORE E-WIND PRIOR TO THE COLD FRONTAL PASSAGE LATER TONIGHT. KBDL TAF...HIGH CONFIDENCE IN TAF. .OUTLOOK /SATURDAY THROUGH TUESDAY/... SATURDAY THROUGH MONDAY...HIGH CONFIDENCE. VFR MOST OF THE PERIOD. ISOLD SHOWER POSSIBLE SAT/SUN. TUESDAY...LOW TO MODERATE CONFIDENCE. AREAS OF MVFR POSSIBLY DEVELOPING WITH SCT SHOWERS BUT TIMING UNCERTAIN. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT-TERM /THROUGH FRIDAY NIGHT/... THROUGH FRIDAY...HIGH CONFIDENCE. E-FLOW PERSISTING OVER THE WATERS INTO TONIGHT WILL BACK NE AND PERHAPS BECOME BLUSTERY WITH GUSTS UP AROUND 20 KTS DURING THE OVERNIGHT HOURS AS A COLD FRONT /PRESENTLY ACROSS MAINE/ SWEEPS S ACROSS THE WATERS ALONG WITH THE CHANCE OF SHOWERS. SEAS COULD RISE EVER BRIEFLY TO 5-FEET ON THE OUTER WATERS... OTHERWISE MAJORITY OF THE TIMEFRAME HAS SUB-SMALL-CRAFT-ADVISORY CRITERIA. FRIDAY NIGHT...LOW CONFIDENCE. CONCERN TOWARDS SATURDAY MORNING OF LOW CLOUDS WITH A MIX OF FOG AND DRIZZLE RESULTING IN SOME VISIBILITY ISSUES. LOW CONFIDENCE AT THIS TIME. WINDS AND SEAS SHOULD BE BELOW SMALL-CRAFT ADVISORY CRITERIA. .OUTLOOK...SATURDAY THROUGH TUESDAY...HIGH CONFIDENCE. SATURDAY...NE WINDS GUSTING TO 20 KT S/SE WATERS WELL N OF COASTAL LOW WITH SEAS POSSIBLY UP TO 5 FT WATERS S AND E OF ACK. SUNDAY...QUIET BOATING WEATHER WITH S/SW WINDS BELOW 15 KT AND SEAS BELOW SCA. MONDAY AND TUESDAY...INCREASING PRE-FRONTAL SW WINDS TO 15-20 KT. WINDS UNCERTAIN TUE AFTERNOON WHICH WILL DEPEND ON TIMING OF A COLD FRONT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...KJC/SIPPRELL SHORT TERM...SIPPRELL LONG TERM...KJC AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL

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