Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 291100 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 700 AM EDT MON JUN 29 2015 .SYNOPSIS... MAINLY DRY WEATHER RETURNS TODAY WITH TEMPERATURES SLIGHTLY COOLER THAN NORMAL. WARMER TEMPERATURES MOVE IN TUESDAY AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT WILL BRING SHOWERS/SCATTERED THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY. SOME STORMS WEDNESDAY MAY BE STRONG ALONG WITH LOCALLY HEAVY RAINFALL. BEHIND THE FRONT... DRIER AND NEAR SEASONABLE WEATHER RETURNS THURSDAY. ANOTHER FRONTAL SYSTEM MAY BRING A ROUND OF SHOWERS AND THUNDERSTORMS FRIDAY AND/OR SATURDAY. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... 7 AM UPDATE... NOT VERY SUMMER-LIKE THIS MORNING WITH LOW CLOUDS/PATCHY FOG/DRIZZLE AND COOL TEMPERATURES IN THE 50S. HOWEVER BROAD AREA OF LOW PRESSURE OVER NEW ENGLAND THIS MORNING WILL LIFT NORTHEAST THIS AFTERNOON. THIS WILL SHIFT WINDS TO THE SW AND THIS LAND TRAJECTORY FOR MUCH OF THE REGION HELP MODIFY/ERODE THE MARITIME AIRMASS OVER THE AREA THIS MORNING. THIS WILL WARM TEMPS INTO THE LOW AND MID 70S THIS AFTERNOON...U60S ALONG THE IMMEDIATE SOUTH COAST. BUFKIT TIME SECTIONS FROM BOTH THE GFS AND NAM INDICATE LOTS OF LOW LEVEL MOISTURE PERSISTING INTO THIS AFTERNOON. SO EXPECTING MORNING STRATUS TO LIFT INTO A SCU/CU DECK WITH A FEW BREAKS OF SUNSHINE DEVELOPING. HOWEVER THEME WILL LIKELY BE MORE CLOUDS THAN SUN TODAY. NEVERTHELESS MUCH BETTER THAN YESTERDAY/S WEATHER. OVERALL NO MAJOR CHANGES FROM PREVIOUS FORECAST. EARLIER DISCUSSION BELOW. ================================================================== TRAPPED LOW LEVEL MOISTURE WILL CONTINUE TO KEEP STRATUS AND SOME DRIZZLE ACROSS THE AREA. SURFACE WINDS HAVE GONE LIGHT OR ARE IN AN EASTERLY FLOW. THIS MAY ALLOW FOR FOG TO DEVELOP IN THE NORMALLY PRONE REGIONS OVER THE NEXT HOUR OR TWO. SCT SHOWERS ACROSS THE BERKS WILL CONTINUE THANKS TO UPSLOPE EASTERLY FLOW. TODAY... SURFACE LOW WILL HEAD TOWARDS THE MARITIMES THIS MORNING ALLOWING FOR THE FLOW TO TURN MORE WESTERLY. THIS WILL HELP DRY THE REGION OUT. STRATUS COULD HANG TOUGH FOR THE MORNING HOURS...BUT SHOULD BREAK UP AROUND NOON. THIS WILL HELP WARM TEMPS BACK TOWARDS SEASONABLE. WENT A FEW DEGREES BELOW GUIDANCE AS LINGERING CLOUDS AS WELL AT 850MB TEMPS AT 9-10 C WILL LIMIT MAX HEATING. LASTLY GUIDANCE HAS A FEW TENTHS OF QPF THIS AFTERNOON. HAVE A LOW CONFIDENCE THAT SHOWERS WILL DEVELOP AS THE LOW LEVELS WILL BE DRY. BUFKIT SOUNDINGS DO SHOW THAT THE ACROSS THE SOUTH SHORE WINDS COULD GUSTS UP TO 25 MPH. SO WITH GOOD MIXING AND DRY LOW LEVELS...NOT ANTICIPATE SHOWERS BUT MORE CLOUDS/VIRGA THIS AFTERNOON. BEACH FORECAST... THERE IS A HIGH RISK OF RIP CURRENT ACROSS SOUTH FACING SHORES OF RI AND THE ISLANDS. THERE IS ALSO A MODERATE RISK OF RIP CURRENTS ACROSS THE EASTERN FACE BEACHES OF MASS. THERE IS THE POTENTIAL THE WAVE GUIDANCE IS UNDER DOING THE PERIOD AND SWELL ALONG EASTERN MASS...SO SWIMMERS SHOULD BE AWARE OF THE RIP CURRENT POTENTIAL. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM TUESDAY/... TONIGHT INTO TUESDAY... WEAK HIGH PRESSURE WILL BUILD IN TONIGHT. THERE IS A LOW PROB OF SOME PATCHY FOG AS WINDS WILL BE LIGHT WITH PARTLY CLOUDY SKIES. HOWEVER...CLOUDS WILL BE ON THE INCREASE AS WAA AND MID-LEVEL RIDGING MOVES OVER THE AREA. TEMPS AND DEWPOINTS WILL BE ON THE RISE ON TUESDAY AS MID-LEVEL RIDGE BUILDS. ACROSS THE GREAT LAKES...SURFACE LOW WILL DEVELOP AS UPPER LEVEL TROUGH DIGS INTO THE MIDWEST. THIS LOW AND ITS ASSOCIATED WARM FRONT WILL MOVE ACROSS THE HUDSON VALLEY AND INTO NORTHERN NEW ENGLAND. ALTHOUGH THINK THAT MOST OF THE REGION WILL REMAIN DRY...WESTERN MASS COULD SEE A POP-UP THUNDERSTORM ALONG WARM FRONTAL PASSAGE DURING THE AFTERNOON HOURS. TEMPERATURES WILL RETURN TO SEASONABLE WITH HIGHS IN THE UPPER 70 TO LOW 80S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * SHOWERS AND SCATTERED THUNDERSTORMS LIKELY TUESDAY NIGHT AND WEDNESDAY...SOME STORMS MAY BE STRONG WITH LOCALLY HEAVY RAINFALL * DRY AND SEASONABLE THURSDAY * RISK OF SHOWERS/T-STORMS AGAIN FRI/SAT - INDEPENDENCE DAY SYNOPTIC OVERVIEW AND MODEL PREFERENCES... AN ACTIVE PATTERN CONTINUES THIS PERIOD WITH UNSETTLED WEATHER AT TIMES IN THE FORM OF SHOWERS/T-STORMS EVERY 2 OR 3 DAYS THIS PERIOD. THIS IS IN RESPONSE TO THE CURRENT HIGH AMPLITUDE FLOW ACROSS NORTH AMERICA PERSISTING. ONLY CHANGE HERE IS THAT THE WESTERN CONUS/ CANADA RIDGE RETROGRADES INTO THE GULF OF ALASKA. THIS SHIFTS THE DOWNSTREAM TROUGH OVER THE GREAT LAKES A BIT FARTHER WEST. HOWEVER AS NEW RIDGING DEVELOPS OVER GREENLAND AND THE DAVIS STRAIT... /SUPPORTING A NEGATIVE NAO/ TROUGHING IS REESTABLISHED OVER ONTARIO INTO THE GREAT LAKES. THIS SETUP SUPPORTS CYCLONIC FLOW ALOFT ACROSS THE GREAT LAKES INTO NEW ENGLAND MUCH OF THIS FORECAST PERIOD... YIELDING THE RISK SHOWERS/T-STORMS EVERY 2 OR 3 DAYS. IN ADDITION THIS ACTIVE AND SUPPRESSED NORTHERN STREAM JET WILL PRECLUDE EXCESSIVE HEAT AND HUMIDITY FROM ADVECTING NORTHEAST INTO NEW ENGLAND. THUS TEMPS AT OR SLIGHTLY COOLER THAN NORMAL. TELECONNECTIONS FROM BOTH THE EPS AND GEFS SUPPORT THIS PATTERN WITH BOTH ENSEMBLE SYSTEMS IN AGREEMENT ON A NEGATIVE NAO/AO AND EPO ALONG WITH A POSITIVE PNA. THUS FORECAST CONFIDENCE ABOVE AVERAGE THIS PERIOD. DAILY SENSIBLE WEATHER... TUE NIGHT/WEDNESDAY...FAIRLY ROBUST NORTHERN STREAM TROUGH APPROACHES WITH WARM FRONTAL CONVECTION LIKELY LATE TUE NIGHT. MULTI MODEL BLEND OFFERS LIKELY POPS TOWARD 12Z WED. THUS WIDESPREAD SHOWERS WITH EMBEDDED THUNDER LIKELY. THEN ON WED FORECAST DILEMMA BECOMES WILL WARM SECTOR AIRMASS OVERSPREAD SOUTHERN NEW ENGLAND? IF SHALLOW COOL AIR IS DISLODGED AND LIFTS NORTH OF THE AREA THE RISK FOR STRONG TO SEVERE STORMS EXIST. HOWEVER IF SHALLOW COOL AIR IS MORE STUBBORN AND PERSIST OVER THE AREA THEN SUBSEVERE STORMS ARE MORE LIKELY. AT THIS TIME RANGE TOO EARLY TO SAY WITH ANY CERTAINTY. NEVERTHELESS...GIVEN GOOD SYNOPTIC SCALE FORCING/DEEP LAYER MOISTURE AND MARGINAL TO MODEST INSTABILITY SHOWERS AND T-STORMS SHOULD BE FAIRLY WIDESPREAD. THUS WILL SIDE WITH LKLY POPS FROM A MULTI-MODEL BLEND. THURSDAY...SHOULD SEE A DRYING TREND WITH SEASONABLE TEMPERATURES BEHIND DEPARTING SHORT WAVE TROUGH AND ATTENDING COLD FRONT. ALTHOUGH SOME UNCERTAINTY ON ADDITIONAL SHORT WAVE ENERGY ROUNDING THE BASE OF THE TROUGH WHICH MAY CLIP CT/RI AND SOUTHEAST MA WITH CLOUDS AND POSSIBLE SHOWERS. THUS LOW FORECAST CONFIDENCE. FRI/SAT/SUN...HIGH CONFIDENCE ON NORTHERN STREAM REMAINING AMPLIFIED AND ACTIVE THIS PERIOD. HOWEVER LOTS OF UNCERTAINTY ON THE TIMING AND DEPTH OF INDIVIDUAL SHORT WAVES AND ATTENDING COLD FRONTS. ENSEMBLES SUGGESTING NORTHERN STREAM MAY BE SUPPRESSED ENOUGH FOR MUCH OF THE CONVECTION TO REMAIN SOUTH AND SOUTHWEST OF NEW ENGLAND. NEVERTHELESS HIGH UNCERTAINTY/LOW CONFIDENCE FORECAST HERE. && .AVIATION /12Z 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/... 12Z UPDATE...NO MAJOR CHANGES FROM 06Z AND 09Z TAFS. TRENDS WILL BE FOR MVFR/IFR TO LIFT TO VFR BY MIDDAY AS WINDS BECOME SW. LOCAL SEABREEZES POSSIBLE. EARLIER DISCUSSION BELOW. =================================================================== TODAY...HIGH CONFIDENCE IN TRENDS BUT TIMING IS UNCERTAIN. LOW CLOUDS AND FOG WILL SHOULD IMPROVE TO VFR THANKS TO DRIER AIR WORKING IN FROM THE WEST. LOW PROB OF A SEA BREEZE ALONG THE MASS EAST COAST. TONIGHT...HIGH CONFIDENCE. VFR CONDITIONS WITH MVFR CIGS POSSIBLE IN RADIATIONAL FOG. TUESDAY...HIGH CONFIDENCE. VFR CONDITIONS WITH WARM FRONT PASSING TO THE WEST. WINDS WILL SWITCH TO A MORE SOUTHERLY DIRECT AND A FEW -SHRA/ISO -TSRA IS POSSIBLE ACROSS WESTERN TERMINALS. KBOS TERMINAL...HIGH CONFIDENCE IN TAF...MODERATE CONFIDENCE IN TIMING. LOW PROBABILITY OF SEA BREEZE TODAY. KBDL TERMINAL...HIGH CONFIDENCE IN TAF...MODERATE CONFIDENCE IN TIMING. OUTLOOK...TUE NIGHT THROUGH FRIDAY... TUE NIGHT AND WED...HIGH PROBABILITY FOR WIDESPREAD SHOWERS WITH SCATTERED TSTMS. RISK OF A FEW STRONG STORMS WED. IFR AND MVFR CONDITIONS LIKELY. THU AND FRI...LOTS OF UNCERTAINTY. FOR NOW WILL SAY VFR BUT COULD SEE MVFR THU ACROSS CT/RI AND SOUTHEAST MA IN POSSIBLE SHOWERS. EVEN MORE UNCERTAINTY REGARDING FRI. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /INTO TUESDAY/...HIGH CONFIDENCE. MONDAY...SMALL CRAFT HEADLINES FOR SEAS WILL CONTINUE FROM LEFTOVER SWELL THROUGH TODAY. COULD ALSO SEE 25 KTS ALONG THE NEAR SHORE SOUTHERN WATERS. SCA HAS BEEN ISSUED. TONIGHT INTO TUESDAY...SEAS WILL BEGIN TO DISSIPATE AS SWELL WEAKENS. OTHERWISE LIGHT WIND OVERNIGHT SWITCHING TO THE SOUTH BY TUESDAY. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUES NIGHT AND WED...WIDESPREAD SHOWERS AND SCATTERED TSTMS LIKELY AHEAD OF APPROACHING COLD FRONT. VSBY LIMITED IN AREAS OF FOG/SHOWERS AND SCATTERED TSTMS. MODEST S-SW WINDS AHEAD OF THE FRONT. THU AND FRI...LOTS OF UNCERTAINTY REGARDING HOW FAR SOUTH OFFSHORE COLD FRONT EXITS. && .EQUIPMENT... KBOX WSR-88D IS OUT OF SERVICE UNTIL AN UNKNOWN TIME. TECHNICIANS HAVE BEEN NOTIFIED AND WILL LOOK INTO THE ISSUE THIS MORNING. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR ANZ232>234. SMALL CRAFT ADVISORY UNTIL 3 AM EDT TUESDAY FOR ANZ235-237. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ250- 251. SMALL CRAFT ADVISORY UNTIL 9 AM EDT TUESDAY FOR ANZ254>256. && $$ SYNOPSIS...NOCERA/DUNTEN NEAR TERM...NOCERA/DUNTEN SHORT TERM...DUNTEN LONG TERM...NOCERA AVIATION...NOCERA/DUNTEN MARINE...NOCERA/DUNTEN EQUIPMENT...

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