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 230809 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 409 AM EDT SAT AUG 23 2014 .SYNOPSIS... AN ISOLATED SHOWER IS POSSIBLE...MAINLY DURING THE EARLY HALF OF THE DAY TODAY...BUT THEN HIGH PRESSURE REGAINS CONTROL INTO SUNDAY. DRY WEATHER WITH A WARMING TREND IS LIKELY DURING THE EARLY AND MIDDLE PORTIONS OF NEXT WEEK. A FRONT MAY APPROACH FROM QUEBEC LATE NEXT WEEK WITH A LOW CHANCE OF UNSETTLED WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... GRADUALLY...UPPER LVL SUBSIDENCE IS TAKING OVER THE COLUMN. THE MOISTURE TRAPPED BENEATH THE SUBSIDENCE INVERSION CONTINUES TO MANIFEST ITSELF AS AN AREA OF LOWER CLOUDS WHICH STREAMS FROM THE HIGH TERRAIN OF THE ADIRONDACK...GREEN AND WHITE MOUNTAINS. THESE ARE ALSO LIKELY THE RESULT OF ONE FINAL SHORTWAVE WHICH...PER LATEST WV IMAGERY IS SLIDING OUT OF QUEBEC AT THE TIME OF THIS WRITING. IT IS THIS LAST FEATURE WHICH WILL DEFINE THE EARLY HOURS OF THE DAY TODAY. MODELS INDICATE JUST ENOUGH LIFT AND UPPER LVL COOLING TO SUPPORT A POP SHOWER OR TWO. NOT EXPECTING THESE SHOWERS TO BE NEARLY AS WIDESPREAD AS PREVIOUS DAYS...AS THIS WAVE IS ALSO USHERING IN A MUCH DRIER AIRMASS WHERE PWATS DROP TO NEAR OR BELOW 1.0 INCHES. FOR NOW...WILL CARRY ONLY SLIGHT CHANCE POPS...SHIFTING FROM E-W AS INVERTED RIDGING REGAINS CONTROL FROM THE E. THE LOWER CLOUDS MAY TAKE A BIT LONGER TO FULLY DISSIPATE...INTO THE AFTERNOON HOURS ESPECIALLY ACROSS E-SE PORTIONS OF THE FA...WHERE MARINE FLOW WILL LIKELY MAINTAIN SOME LOWER LVL MOISTURE. GIVEN THE GRADUAL EXPECTED CLEARING...EXPECT HIGHS TO BE A BIT WARMER THAN FRI...BUT STILL BELOW NORMAL...MAINLY LOW-MID 70S. NE WINDS COULD BE BREEZY AS WELL...WITH A FEW GUSTS 15-20 MPH POSSIBLE AT TIMES ESPECIALLY ACROSS ERN MA AND RI. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT... AS HEIGHTS RISE FROM LONGWAVE TROF MOVING WELL SE OF THE REGION...SFC INVERTED RIDGE WILL BACK IN FROM THE NE. THIS SHOULD LEAD TO GRADUALLY CLEARING SKIES ACROSS MUCH OF THE FA...EXCEPT MAYBE IN THE HIGHER TERRAIN OF NW MA AND SRN NH. ALSO NOTE THAT SFC PRES GRADIENT WILL SLACKEN. THEREFORE...COULD ACTUALLY SEE SOME RADIATIONAL COOLING AND GIVEN THAT DWPTS WILL FALL THROUGH THE DAY BACK INTO THE 50S...WILL LIKELY SEE SEVERAL MINS IN THE LOW-MID 50S AS WELL. IF...THERE IS ENOUGH CLEARING IN THE NW VALLEYS...NOT OUT OF THE QUESTION SOME 40S ARE SEEN AS WELL. HAVE HIGHLIGHTED THIS IN THE MINS FOR THIS UPDATE. DRIER AIR IS LIKELY TO LIMIT FOG SOMEWHAT...BUT WITH RADIATIONAL PROCESSES SOME PATCHY FOG CAN/T BE RULED OUT. SUN... HIGH PRES REMAINS IN CONTROL THROUGH THE DAY. ASIDE FROM DIURNAL CU IN THE INTERIOR...PLENTY OF MIXING SHOULD ALLOW HIGHS TO REBOUND INTO THE UPPER 70S AND LOW 80S THANKS TO H85 TEMPS INCREASING TO ABOUT +12C. ONLY CAVEAT ARE NEAR SHORE LOCATIONS WHERE SEA BREEZES ARE POSSIBLE THANKS TO A WEAK PRES GRADIENT. CURIOUS...SOME MODELS ARE INDICATING A CONVECTIVE QPF BULLSEYE NEAR THE BERKSHIRES WHICH MAY HAVE TO BE WATCHED...BUT FOR NOW FEEL THAT THE DRIER AIR SHOULD OVERCOME. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * DRY WEATHER EXPECTED FOR MOST OF THIS PERIOD * WARMER...MORE HUMID CONDITIONS MOVE IN AROUND EARLY TO MIDDLE PORTIONS OF NEXT WEEK * UNCERTAINTY CONTINUES LATE NEXT WEEK AS A COLD FRONT APPROACHES FROM QUEBEC OVERVIEW AND MODEL PREFERENCES...23/00Z GUIDANCE REMAINS IN RATHER GOOD AGREEMENT WITH THE SYNOPTIC PATTERN THROUGH TUESDAY. THE DETAILS START TO BECOME MURKY LATE WEDNESDAY...EVEN THOUGH THERE ARE SOME COMMON THEMES IN THE OVERALL SOLUTIONS. SINCE SOME OF THESE DETAILS INVOLVE A POTENTIAL TROPICAL SYSTEM APPROACHING THE COAST... THE IMPACTS ON SENSIBLE WEATHER COULD BE SIGNIFICANT. USED A BLEND OF AVAILABLE GUIDANCE THROUGH WEDNESDAY TO SMOOTH OVER THE MINOR DIFFERENCES. STILL USED A BLEND...LEANING MORE HEAVILY UPON ENSEMBLE MEANS...AFTER WEDNESDAY DUE TO LOW CONFIDENCE IN ANY ONE DETERMINISTIC SOLUTION. ECMWF AND CANADIAN HAVE SIMILAR TIMING...WITH THE GFS REMAINING THE SLOWEST. GEFS MEAN SOLUTION IS CLOSER TO THE TIMING FROM THE INTERNATIONAL MODELS. DETAILS... MONDAY THROUGH WEDNESDAY...HIGH PRESSURE REMAINS IN CONTROL OF OUR WEATHER...LINGERING OVERHEAD MONDAY AND TUESDAY...BEFORE SLIPPING SOUTH OF OUR REGION FOR WEDNESDAY. EXPECTING MORE SEASONABLE TEMPERATURES DURING THIS PERIOD. WITH LIGHT PRESSURE GRADIENT MONDAY AND TUESDAY...LOCAL SEA BREEZES WILL LIKELY DEVELOP...KEEPING IT A BIT COOLER ALONG THE SHORELINE. SOME CLOUDS MAY START TO MOVE IN WEDNESDAY NIGHT...BUT TIMING IN QUESTION. THURSDAY-FRIDAY...LOWER CONFIDENCE FOR THIS PORTION OF THE FORECAST. FOR NOW...MAY SEE A FRONTAL SYSTEM TRY TO MOVE SOUTH OUT OF QUEBEC. QUESTIONS ABOUND WITH THE TIMING OF THIS FRONT...AS WELL AS HOW MUCH MOISTURE WILL BE ASSOCIATED WITH THIS SYSTEM. WITH A HIGH PRESSURE TO THE SOUTH...NEITHER EXPECTING THIS FRONT TO SET ANY SPEED RECORDS...NOR MOVE TOO FAR SOUTH OF OUR REGION IT IF MAKES IT THAT FAR. DID KEEP ONLY LOW CHANCE POPS MAINLY FOR THE INTERIOR FOR THURSDAY AFTERNOON/EVENING. VERY LITTLE INSTABILITY WITH THIS...BUT CAN NOT RULE OUT AN ISOLATED SHOWER OR THUNDERSTORM. CURRENT FORECAST SUGGESTS A DRIER AND COOLER DAY FRIDAY. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...THROUGH SUNDAY...HIGH CONFIDENCE. THROUGH MID DAY... PERIODS OF MVFR AND ISOLATED IFR IN LOW CIGS WILL CONTINUE BUT GRADUALLY LIFT ESPECIALLY AFTER SUNRISE. SOME AREAS REMAIN VFR. MOST TERMINALS SHOULD BE VFR BY MID DAY AND THEN REMAIN SO. NOT EXPECTED MUCH FOG THIS MORNING. WINDS MAINLY NE. AFTER MID DAY TODAY... MAINLY VFR. SOME PATCHY FOG POSSIBLE TONIGHT BUT MAINLY AT TYPICALLY PRONE TERMINALS. KBOS TERMINAL...HIGH CONFIDENCE IN OVERALL TAF TRENDS...LOWER CONFIDENCE IN EXACT TIMING OF IMPROVEMENT LATER THIS MORNING. KBDL TERMINAL...HIGH CONFIDENCE IN TAF TRENDS...LOWER CONFIDENCE IN EXACT TIMING OF IMPROVEMENT. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... HIGH CONFIDENCE VFR. LOW PROBABILITY OF PATCHY MVFR/IFR FOG EACH NIGHT. SEA BREEZES POSSIBLE MONDAY AND TUESDAY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM...THROUGH SUNDAY...HIGH CONFIDENCE. NE FLOW CONTINUES THROUGH THE DAY TODAY...SOME GUSTS MAY APPROACH 15-20 KT THROUGH THE EVENING HOURS. A BUILDING SWELL MAY APPROACH 4 FT ON THE OUTERMOST SRN WATERS AS WELL. THESE CONDITIONS ARE LIKELY TO LINGER UNTIL OVERNIGHT TONIGHT...WHEN HIGH PRES BUILDS OVER THE WATERS. LIGHTER...MORE N WINDS EXPECTED ON SUN. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... HIGH CONFIDENCE. HIGH CONFIDENCE. QUIET BOATING WEATHER IS EXPECTED FOR MUCH OF THIS PERIOD WITH HIGH PRESSURE ACROSS THE WATERS. LOW PROBABILITY OF PATCHY OVERNIGHT FOG LIMITING VISIBILITIES. SEAS MAY APPROACH 5 FT ACROSS THE OUTERMOST SOUTHERN COASTAL WATERS LATE WEDNESDAY FROM INCREASING SOUTH SWELLS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/DOODY NEAR TERM...DOODY SHORT TERM...DOODY LONG TERM...BELK AVIATION...BELK/DOODY MARINE...BELK/DOODY

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