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 101923 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 323 PM EDT THU JUL 10 2014 .SYNOPSIS...
-- Changed Discussion --
A STALLED COLD FRONT JUST OFFSHORE WILL FINALLY MOVE SOUTH OF THE REGION EARLY FRIDAY. DRIER AND MORE SEASONABLE WEATHER WILL THEN CONTINUE INTO SATURDAY. UNSETTLED WEATHER RETURNS LATE SUNDAY INTO EARLY NEXT WEEK WITH THE RISK OF SHOWERS AND THUNDERSTORMS ALONG WITH INCREASING HUMIDITY.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 7 PM THIS EVENING/...
-- Changed Discussion --
CURRENTLY...MASS FIELDS AND AVAILABLE OBS SUGGEST COLD FRONTAL BOUNDARY IS STALLED JUST OFF OF MAINLAND SRN NEW ENGLAND...FROM ACK SOUND SW TO LONG ISLAND. CONVECTION NEAR SRN NJ AND THE DELMARVA HAS BEGUN TO PUSH E...AND THE NRN EXTENT LOOKS TO CLIP ESPECIALLY ACK BY LATE THIS AFTERNOON AND EVENING. CONVECTIVE THREAT IS LIKELY TO STAY JUST TO THE S HOWEVER...SINCE INSTABILITY IS INCREASES AND BEST THETA-E RIDGE EXTENDS S OF THE CURRENT FRONTAL POSITION. WILL MAINTAIN ISO TS IN THE WX FOR THE TIME BEING...BUT FEEL THAT ANYTHING THAT EFFECTS SRN NEW ENGLAND WILL BE JUST A RAIN SHIELD BY THE TIME IT ARRIVES. WILL NEED TO WATCH THE DEVELOPMENT OF A WEAK FRONTAL WAVE OFF THE DELMARVA LIKELY TRIGGERED BY SCT CONVECTION CURRENTLY IN MARYLAND AND DELAWARE...THIS MAY BE THE LAST THREAT FOR RAIN ACROSS ACK/MVY OR EXTREME SRN CAPE COD DURING THE OVERNIGHT HOURS...WILL CONTINUE A BAND OF CHANCE...TAPERING TO SLIGHT CHANCE POPS THROUGH ABOUT 06 FOR THIS THREAT. AFTER THE FRONTAL WAVE...THE COLD FRONT ITSELF SHOULD BEGIN A LOW MIGRATION FURTHER S. ASIDE FROM THIS RAIN THREAT...DRYING DWPTS WILL CONTINUE INTO TONIGHT AS HIGH PRES SLOWLY NOSES IN FROM THE W. THE COMBINATION OF A REMNANT CI SHIELD FROM CONVECTION TO THE S IS LIKELY TO MITIGATE RADIATIONAL COOLING SOMEWHAT...SO EXPECT OVERNIGHT LOWS TO BE A BIT WARMER THAN THEY OTHERWISE COULD BE. EXPECT LOWS MAINLY IN THE UPPER 50S TO MID 60S. A FEW NW VALLEYS...AWAY FROM THE CI SHIELD MAY DROP INTO THE LOW 50S THANKS TO A BETTER SHOT FOR RADIATIONAL COOLING.
-- End Changed Discussion --
&& .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM FRIDAY/...
-- Changed Discussion --
TOMORROW... WITH WEAK FRONTAL WAVE SHIFTING WELL TO THE SE OF NEW ENGLAND EARLY IN THE MORNING...EXPECT THAT COLD FRONT WILL FINALLY BEGIN A FURTHER MIGRATION TO THE S...ALLOWING HIGH PRES TO BEGIN TO CREST ACROSS THE REGION DURING THE DAY. ASIDE FROM SOME EARLY CI FROM THE WAVE...CLOUDS WILL COME IN THE FORM OF DIURNAL CU AS MODELS SHOW A MODEST MOISTURE LAYER JUST ABOVE THE BL. MODELS ARE STILL TRYING TO INDICATE A POCKET OR TWO OF VERY LIGHT QPF THANKS TO RAZOR THIN CAPE PROFILE ABOVE THE MIXED LAYER PER LATEST SOUNDINGS. HOWEVER...AGREE WITH PREVIOUS FORECAST SHIFT THAT THE OVERALL COLUMN LOOKS MUCH TOO DRY AT THIS TIME. THEREFORE...WILL CONTINUE WITH NIL POPS. TYPICAL MID SUMMER MIXING PROFILES AND H85 TEMPS NEAR +13C SUPPORT HIGHS MAINLY LOW-MID 80S /NEAR TYPICAL FOR THIS TIME OF YEAR/ EXCEPT NEAR SHORELINES WHERE WEAK PRES GRADIENT WILL SUPPORT SEA BREEZE DEVELOPMENT. TOMORROW NIGHT... SIMILAR SETUP TO THU NIGHT AS DWPTS FALL INTO THE LOW 50S. HOWEVER...DO EXPECT A BIT MORE CLEARING AND A GENERALLY WEAK PRES GRADIENT. THEREFORE...MIGHT SEE A BIT MORE RADIATIONAL COOLING ACROSS THE REGION. HAVE MINS A BIT COOLER...MAINLY IN THE LOW 50S TO AROUND 60F. POSSIBLY A LITTLE WARMER IN THE URBAN SPOTS.
-- End Changed Discussion --
&& .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGHLIGHTS... * PLEASANT/DRY WEATHER AND LESS HUMID FRI NIGHT/SAT * BECOMING UNSETTLED LATE SUN INTO EARLY NEXT WEEK SYNOPTIC SCALE FLOW AND MODEL PREFERENCES... FLOW TEMPORARILY DEAMPLIFIES EARLY IN THE PERIOD TO PROVIDE DRIER AND LESS HUMID MID SUMMER WEATHER ACROSS SOUTHERN NEW ENGLAND. BY LATER SUNDAY/SUN NIGHT AND ESPECIALLY EARLY NEXT WEEK THE UPPER AIR PATTERN UNDERGOES SIGNIFICANT AMPLIFICATION WITH A PIECE OF THE POLAR VORTEX DIVING SOUTHWARD INTO THE GREAT LAKES. GEFS ANOMALIES SUGGEST 500 MB HEIGHTS FALL TO ABOUT -3 SD BELOW OVER THIS REGION EARLY NEXT WEEK. THIS CLOSED LOW WILL THEN TRACK NORTHEAST INTO SOUTHERN ONTARIO AND QUEBEC EARLY NEXT WEEK. HOWEVER THE LEADING EDGE OF ITS FRONTAL ZONE WILL PROVIDE UNSETTLED WEATHER FOR SOUTHERN NEW ENGLAND POSSIBLY AS EARLY AS LATER SUNDAY BUT MORE LIKELY MON AND TUE OF NEXT WEEK. ALL OF THE MODEL GUIDANCE INCLUDING THE GEFS AND ECENS IS IN VERY GOOD AGREEMENT ON THE EVOLUTION OF THIS HIGH AMPLITUDE TROUGH ALONG WITH THE SYNOPTIC SCALE FLOW PATTERN ACROSS NEW ENGLAND. THUS WILL FOLLOW A MODEL BLEND FOR THIS PORTION OF THE FORECAST. DAILY DETAILS... FRI NIGHT AND SATURDAY...VERY PLEASANT DRY WEATHER WITH COMFORTABLE HUMIDITY AND LIGHT WINDS AS HIGH PRES CREST OVER THE REGION. WEAK PGRAD WILL SUPPORT AFTERNOON SEA BREEZES KEEPING THE COASTLINE SLIGHTLY COOLER THAN THE INTERIOR. DEW PTS IN THE 50S WILL SUPPORT LOWS IN THE U50S TO L60S AND HIGHS 80-85. SUN/MON/TUE....WEATHER BECOMES UNSETTLED AS UPPER AIR PATTERN AMPLIFIES SIGNIFICANTLY. THE GFS AND ITS ENSEMBLES ARE ON THE FAST EDGE OF THE GUIDANCE WITH THE THREAT OF SHOWERS ARRIVING SUN. REMAINDER OF THE GUID IS SLOWER KEEPING DRY WEATHER HERE UNTIL NIGHTFALL/SUN EVENING. HIGHER RISK OF SHOWERS/T-STORMS COMES MON AND TUE AS FULL LATITUDE TROUGH OVER THE GREAT LAKES ADVECTS NORTHEAST INTO SOUTHERN ONTARIO AND QUEBEC. STRONG FRONTAL ZONE ASSOCIATED WITH THIS SYSTEM WHICH WILL IMPACT THE REGION MON AND TUE WITH AN INCREASED RISK OF SHOWERS/T-STORMS. TROUGH MAY HAVE ENOUGH AMPLIFICATION TO BACK THE MID LEVEL FLOW FOR GOOD ATLC INFLOW YIELDING HEAVY RAINFALL THREAT. ALSO TURNING WARMER AND MORE HUMID THIS PERIOD AS WELL. MIDDLE OF NEXT WEEK...ENSEMBLES SUGGEST MID/UPR LVL TROUGH SHOULD BE MOVING OFFSHORE AROUND THE MIDDLE OF NEXT WEEK. THIS WOULD SUPPORT A TREND TOWARD DRIER AND LESS HUMID WEATHER. && .AVIATION /17Z THURSDAY THROUGH MONDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE FOR MOST EXCEPT ACK THIS EVENING. THROUGH TONIGHT... VFR FOR MOST. ONLY CAVEAT WILL BE ACK...WHERE ANOTHER ROUND OF STRATUS AND LOW VSBYS ARE POSSIBLE IN FOG UNTIL LATE. ALSO...SOME RAIN POSSIBLE LATE THIS AFTERNOON/EVENING FOR ACK. OTHERWISE...LIGHT LATE DAY SEA BREEZES AT NEAR SHORE TERMINALS WITH LIGHT W WINDS ELSEWHERE. TOMORROW AND TOMORROW NIGHT... VFR. SEA BREEZES ONCE AGAIN LIKELY AT NEAR SHORE TERMINALS. START TIME IS LIKELY 15Z-17Z. KBOS TAF...HIGH CONFIDENCE IN TAF. AFTERNOON SEA BREEZE MAY TAKE UNTIL 18Z-20Z TO START THIS TODAY. SHOULD START 14-15Z TOMORROW. KBDL TAF...HIGH CONFIDENCE IN TAF. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE. FRIDAY NIGHT AND SATURDAY...HIGH CONFIDENCE FOR VFR/DRY WEATHER AND LIGHT WINDS. SUNDAY-MONDAY...VFR TO START BUT LOWERING TO MVFR LATE SUN/SUN NIGHT AND ESPECIALLY MON AS RISK OF SHOWERS/T-STORMS INCREASES. LOCALLY HEAVY DOWNPOURS POSSIBLE IN ANY THUNDERSTORMS. && .MARINE...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /TODAY THROUGH FRI NIGHT/...HIGH CONFIDENCE. A COLD FRONT WILL SLOWLY MOVE S OF THE WATERS EARLY TOMORROW...UNTIL THEN A FEW POCKETS OF SHOWERS...AND POSSIBLY EVEN A RUMBLE OF THUNDER IS POSSIBLE MAINLY ON THE WATERS S OF BLOCK ISLAND TO NANTUCKET THROUGH THE EARLY HALF OF THE OVERNIGHT. WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH FRI NIGHT. OUTSIDE OF AN ISOLATED TS. OUTLOOK...SATURDAY THROUGH TUESDAY...MODERATE CONFIDENCE. FRIDAY NIGHT THROUGH SUNDAY...IDEAL BOATING WEATHER WITH GOOD VSBY/DRY WEATHER AND LIGHT WINDS AS HIGH PRES CREST OVER THE WATERS. SUNDAY NIGHT-MONDAY...HIGH PRES MOVES OFFSHORE WITH RISK OF SHOWERS/T-STORMS INCREASING. SSW WINDS INCREASE AS WELL.
-- End Changed Discussion --
&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...NOCERA/DOODY NEAR TERM...DOODY SHORT TERM...DOODY LONG TERM...NOCERA AVIATION...NOCERA/DOODY MARINE...NOCERA/DOODY

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