Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | 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 250752 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 352 AM EDT MON MAY 25 2015 .SYNOPSIS... A WARM FRONT WILL MOVE ACROSS THE REGION TODAY...FOLLOWED BY WARM AND MUGGY CONDITIONS LASTING INTO NEXT WEEKEND. THE THREAT FOR SCATTERED SHOWERS AND THUNDERSTORMS WILL INCREASE FROM LATE WEDNESDAY THROUGH THURSDAY AND AGAIN OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 345 AM UPDATE...AN ILL-DEFINED WARM FRONT STRETCHED FROM EASTERN MICHIGAN SOUTHEASTWARD THROUGH THE APPALACHIANS TO NEAR DELMARVA EARLY THIS MORNING. HIGH LEVEL CIRRUS CLOUDS COVERED SOUTHERN NEW ENGLAND AHEAD OF IT. THE WARM FRONT WILL MOVE NORTHEAST AND ACROSS OUR REGION THIS AFTERNOON. THE CLOUD COVER...ALTHOUGH PRESENT...IS NOT EXPECTED TO BLOCK OUT ALL SUNSHINE. THUS THE WARM LATE-MAY SUNSHINE IS EXPECTED TO ALLOW TEMPERATURES TO CLIMB WELL INTO THE 80S. 925 MB TEMPS HIT 17C ON SUNDAY AND THEY ARE FORECAST TO HIT 20C THIS AFTERNOON. HAVE GONE A FEW DEGREES HIGHER THAN GUIDANCE. EXCEPTIONS WILL BE ON CAPE COD AND THE ISLANDS WHERE IT WILL REMAIN IN THE UPPER 60S AND 70S AND ON THE TIP OF CAPE ANN WHERE A SOUTHWEST TO SOUTH WIND OFF THE COOL OCEAN WILL LIKELY HOLD TEMPERATURES TO THE 70S. THICKER CLOUD COVER COULD HOLD TEMPERATURES BACK...BUT AM THINKING THAT WOULD MAINLY BE OVER NORTHERN NEW ENGLAND WHERE THE BETTER LIFTING PROCESSES ARE. ALTHOUGH THE GFS HAS SOME PRECIPITATION FOR NORTHERN MA...AM EXPECTING A COMPLETELY DRY MEMORIAL DAY. ALL MODELS SHOW THE GRADIENT TIGHTENING UP AND SOUTHWEST WINDS INCREASING TO 30-35 KNOTS JUST ABOVE THE SURFACE LATE THIS AFTERNOON ALONG THE SOUTH COAST. BUFKIT SHOWS THE POTENTIAL FOR A BRIEF PERIOD OF WIND GUSTS TO 20-28 MPH OVER LAND AREAS WITHIN AN HOUR OR TWO OF 5 PM. THE WIND GUSTS REMAIN LESS THAN 20 KNOTS OVER THE COASTAL WATERS DUE TO A PRONOUNCED INVERSION NEAR THE SURFACE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... TONIGHT...SOUTHWEST WINDS OF 10 TO 15 MPH OVERNIGHT WILL HELP INCREASE DEWPOINTS TO THE UPPER 50S AND ALLOW OVERNIGHT TEMPERATURES TO REMAIN IN THE 60S. A SOUTHWESTERLY LOW LEVEL JET OF AROUND 40 KNOTS AT 925 MB WILL BE JUST ABOVE THE SURFACE BUT THE AIR SHOULD BE DECOUPLED ENOUGH TO PREVENT STRONG WIND GUSTS AT THE GROUND. COULD SEE SOME PATCHY FOG DEVELOPING ALONG THE SOUTH COAST/CAPE COD/ISLANDS. VERY SLIGHT CHANCE OF A SHOWER ALONG THE MA/NH BORDER. AGAIN...MOST OF THE ENERGY WILL REMAIN TO OUR NORTH. TUESDAY...SOUTHERN NEW ENGLAND REMAINS IN INCREASINGLY WARM AND MOIST AIR FLOW AROUND A BERMUDA HIGH PRESSURE SYSTEM. HIGH CLOUDS IN THE MORNING MAY THIN ALLOWING SUNSHINE FOR A TIME. IT WILL BE BREEZY AND VERY WARM. WITH OVERNIGHT LOWS HOLDING IN THE 60S...IT WILL NOT TAKE LONG FOR TEMPERATURES TO ZOOM INTO THE 80S...MAXING OUT IN THE UPPER 80S ESPECIALLY IN THE CONNECTICUT AND MERRIMACK VALLEYS...BUT STILL UPPER 60S AND 70S AT THE SOUTH COAST/CAPE COD/ ISLANDS. LATE IN THE AFTERNOON...THERE COULD BE ENOUGH INSTABILITY IN NORTHWEST CT AND WESTERN MA TO POP SOME SCATTERED THUNDERSTORMS. WE HAVE A 20 TO 30 PERCENT PROBABILITY IN THOSE AREAS...BUT REMAINING DRY IN EASTERN SECTIONS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... */ HIGHLIGHTS... - WARM AND MUGGY CONDITIONS - THREAT OF MARINE STRATUS / FOG ALONG THE S COAST - SHOWER / THUNDERSTORM CHANCES BEGINNING LATE WEDNESDAY - THREAT OF HEAVY RAIN AND POSSIBLE SEVERE WEATHER - POTENTIAL LULL IN ACTIVITY FRIDAY - ANOTHER ROUND OF SHOWERS / THUNDERSTORMS FOR THE WEEKEND */ DISCUSSION... TUESDAY NIGHT - WEDNESDAY NIGHT: RIDGE OF HIGH PRESSURE GRADUALLY DEAMPLIFIES ALLOWING MID-LEVEL ENERGY ALONG WITH LOW- TO MID-LEVEL SW-CONVERGENT FLOW AND RRQ OF AN UPPER-LEVEL JET TO SLINK SE TOWARDS SNE. SHOWERS/THUNDERSTORMS CHANCES INCREASE. INITIAL ACTIVITY LOOKS TO DEVELOP ACROSS PA / UPSTATE NY BY AFTERNOON WITH DAYTIME HEATING. FOCUS APPEARS TO BE ALONG A PRE-FRONTAL BOUNDARY PARALLEL WITH LOW- LEVEL THETA-E/INSTABILITY AXES PRESSING E WITH THE WSW STEERING FLOW INTO N/W NEW ENGLAND LATE INTO THURSDAY MORNING. LIKELY SOME SEVERE TO THE W. OUTCOMES UNCERTAIN FOR HERE. PER BUFKIT CAPPING INVERSION ALONG WITH LOW- TO MID-LEVEL DRY AIR LINGERS. H925-85 SW-FLOW IS DIVERGENT. SHOWER ACTIVITY LIKELY PUSHES E INTO THE FORECAST AREA BUT LOSES ITS PUNCH AS IT DOES SO. SHOWERS POTENTIALLY LINGERING INTO THE FOLLOWING MORNING. WITH ANTICIPATED ELEVATED INSTABILITY THUNDERSTORM ACTIVITY NOT OUT OF THE QUESTION. OTHERWISE... WARM / MUGGY CONDITIONS WITH S-FLOW OF HIGHER DEWPOINT AIR N...THOUGH MID- TO HIGH-LEVEL CLOUD DECKS MAY LIMIT HEATING. MARINE STRATUS / FOG LIKELY TO BE AN ISSUE FOR MUCH OF THE FORECAST PERIOD FOR S/SE- COASTAL COMMUNITIES AS MOISTURE POOLS BENEATH A STOUT WARM-DRY- SUBSIDENCE INVERSION. THURSDAY - THURSDAY NIGHT: MAIN DRIVING FORCE OF MID-LEVEL ENERGY AND ATTENDANT JET-STREAK LIFTS NE RESULTING IN A COOL FRONT PUSHING SE OUT OF CANADA TO BECOME DIFFUSE INTO THE OVERNIGHT HOURS. THIS IN ADDITION TO POSSIBLE CLOUD COVER LEFT-OVER FROM WEDNESDAY PUTS INTO QUESTION OF SHOWER/THUNDERSTORM DEVELOPMENT. THOUGH THE BOUNDARY- LAYER MAY NOT DESTABILIZE...MID-LEVEL COOLING LENDING TO INCREASED ELEVATED INSTABILITY AND THE SUGGESTION OF PERHAPS SOME MID- TO UPPER-LEVEL FORCING /IN ADDITION TO THE CONSENSUS OF DECENT THETA-E AND INSTABILITY AXWS ACROSS SNE/ YIELDS CONTINUED CHANCE SHOWER / THUNDERSTORM THREAT. DECENT SHEAR SO A SEVERE THREAT IS POSSIBLE BUT HAVE GREATER CONFIDENCE TOWARDS A HEAVY RAIN THREAT. PWATS IN EXCESS OF 1.5-INCHES WITH FREEZING LEVEL HEIGHTS OF 11-12 KFT. CONTINUING WITH A WARM-MUGGY THEME WITH RESPECT TO CONDITIONS AS WELL AS MARINE STRATUS / FOG BEING AN ISSUE ALONG THE S/SE-COAST. FRIDAY - FRIDAY NIGHT: DISCREPANCIES AMONG FORECAST GUIDANCE. WHILE THE ENVIRONMENT LOOKS PRIME FOR SHOWER/THUNDERSTORM DEVELOPMENT... NOT A LOT OF FORCING APPARENT. OFFSHORE HIGH PRESSURE LOOKS TO BE INFLUENTIAL AS RIDGING ENHANCES ALOFT EVER SLIGHTLY AHEAD OF A WEEKEND DISTURBANCE. BIGGEST DISCREPANCY CENTERS AROUND MOISTURE AVAILABILITY TO WHICH GFS BUFKIT PROFILES SUGGEST CAN DESTABILIZE. WILL KEEP WITH SLIGHT CHANCE POPS FOR THE PERIOD. WEEKEND - EARLY NEXT WEEK: AGREED UPON THAT ENERGY DIVING S ROUND THE N CANADIAN VORTEX MEETS UP WITH ENERGY OUT OF THE CENTRAL CONUS PUSHING A SURFACE FRONTAL BOUNDARY S ACROSS THE NE CONUS. UNCLEAR AS TO ITS EVOLUTION...WHETHER IT STALLS. FORECAST INTO EARLY NEXT WEEK BECOMES COMPLICATED. OF CERTAINTY IS THAT A PRIMED ENVIRONMENT LOOKS TO EXIST AHEAD OF THE FRONTAL BOUNDARY BENEATH DEEP-LAYER FORCING. THIS SHOULD YIELD LIKELY SHOWER/THUNDERSTORM ACTIVITY. BUT WITH TIMING AND LONGEVITY UNCERTAIN WILL KEEP WITH CHANCE POPS. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... 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...VFR. ANY PATCHES OF MVFR VSBY IN FOG ALONG THE S COAST/ CAPE COD/ISLANDS EARLY THIS MORNING SHOULD DISSIPATE BY MID MORNING. SW WINDS MAY GUST TO 25 KT OVER THE INTERIOR 20-23Z. TONIGHT...VFR. MAY SEE PATCHY FOG WITH MVFR VSBYS LATE S COAST/ CAPE COD/ISLANDS. SW WINDS WILL BE UP TO 40 KT AT 1000-2000 FT ABOVE THE SURFACE. NOT QUITE STRONG ENOUGH FOR LOW LEVEL WIND SHEAR TO BE INSERTED INTO TERMINALS...BUT IMPORTANT TO BE AWARE OF. TUESDAY...VFR. COULD STILL HAVE SOME PATCHY MVFR VSBYS IN FOG NEAR THE S COAST...MAINLY EARLY. CHANCE OF A TSTM WITH MVFR VSBYS IN NW CT AND WESTERN MA...INCLUDING BDL/BAF AND IN THE BERKSHIRES LATE IN THE AFTERNOON. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY NIGHT...MODERATE CONFIDENCE. BREEZY SW-FLOW WITH 20 KT GUSTS AT TIMES. IFR STRATUS / FOG POSSIBLE ACROSS THE S/SE-COAST. INCREASING CHANCES FOR -SHRA/TSRA BEGINNING LATE WEDNESDAY TO W...MOST EVERYWHERE THURSDAY...CONCLUDING EARLY FRIDAY. TEMPO MVFR-IFR WITH ANY ACTIVITY. && .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...SW WINDS CONTINUE...GUSTING UP TO 20 KT ESPECIALLY IN THE LATE AFTERNOON. SEAS MAINLY 2 TO 4 FT. TONIGHT...SW WINDS INCREASE TO 20 TO 25 KT. EXPECTING LOW LEVEL INVERSION TO PREVENT STRONGER WINDS ALOFT FROM MAKING IT DOWN TO THE SEA SURFACE. SEAS BUILD TO 5-6 FT ON THE SOUTHERN WATERS THIS EVENING AND THE EASTERN OUTER WATERS OVERNIGHT. AS A RESULT... A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THESE AREAS THROUGH TUE. TUESDAY...GUSTY SW WIND FLOW OF 20 TO 25 KT CONTINUES OVER THE OUTER WATERS...AROUND THE WEST SIDE OF A BERMUDA HIGH PRESSURE SYSTEM. HAVE INCLUDED NANTUCKET SOUND IN THE SMALL CRAFT ADVISORY FOR TUE AS WIND GUSTS COULD REACH 20 TO 25 KT THERE AS WELL. A FEW FOG PATCHES WITH RESTRICTED VISIBILITY POSSIBLE ON THE SOUTHERN COASTAL WATERS. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY NIGHT...MODERATE CONFIDENCE. PERSISTENT SW-FETCH WITH GUSTS AROUND 20-25 KTS AT TIMES. STRONGEST WINDS ALONG THE NEAR-SHORE WATERS. WAVE HEIGHTS IN EXCESS OF 5-FEET WITH SWELL AND WIND-WAVE MOSTLY ON THE OUTER WATERS BUT GETTING INTO THE S INNER SOUNDS. DENSE FOG ANTICIPATED LENDING TO VISIBILITY RESTRICTIONS. && .FIRE WEATHER... EXPECT DEWPOINTS TO SLOWLY BUT STEADILY RISE INTO THE 50S TODAY. SW WINDS OF 10-20 MPH ARE EXPECTED... HOWEVER THERE COULD BE A BRIEF PERIOD OF 25 MPH GUSTS WITHIN AN HOUR OR TWO OF 5 PM. FORECASTED MINIMUM RH VALUES WILL BE FROM 35 TO 40 PERCENT OVER THE INTERIOR TODAY...AND 45 TO 55 PERCENT ON THE SOUTH COAST/CAPE COD/ISLANDS. WITH THE INCREASING HUMIDITY...EXPECT LOWERED FIRE WEATHER RISK SO WILL NOT BE ISSUING A STATEMENT AT THIS TIME. ALTHOUGH IT WILL BE WARMER ON TUE...DEWPOINTS WILL ALSO BE RISING KEEPING MINIMUM RELATIVE HUMIDITIES FROM 40 TO 50 PERCENT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 AM TO 6 PM EDT TUESDAY FOR ANZ232. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM EDT TUESDAY FOR ANZ235-256. SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM EDT TUESDAY FOR ANZ250- 254-255. && $$ SYNOPSIS...FIELD/SIPPRELL NEAR TERM...FIELD SHORT TERM...FIELD LONG TERM...SIPPRELL AVIATION...FIELD/SIPPRELL MARINE...FIELD/SIPPRELL FIRE WEATHER...FIELD

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