Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 070816 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 416 AM EDT TUE JUL 7 2015 .SYNOPSIS... A COLD FRONT MOVES THROUGH SOUTHERN NEW ENGLAND WEDNESDAY BRINGING SHOWERS AND THUNDERSTORMS...SOME WITH HEAVY DOWNPOURS. THE FRONT MOVES SOUTH OF NEW ENGLAND WEDNESDAY NIGHT AND STALLS...ALLOWING ANOTHER ROUND OF SHOWERS AND STORMS THURSDAY. HIGH PRESSURE THEN BUILDS IN WITH FAIR WEATHER FOR FRIDAY AND SATURDAY. ANOTHER WEATHER SYSTEM APPROACHES EARLY NEXT WEEK AND MAY BRING MORE WET WEATHER. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 11 PM UPDATE... DEWPTS HAVE RISEN QUICKLY SINCE 00Z ACROSS THE REGION...MAINLY IN THE LOWER-MID 60S ACROSS THE REGION. WITH THE HIGHER DEWPTS ESPECIALLY ACROSS S COASTAL AREAS...EXPECT TEMPS TO LEVEL OFF A BIT MILDER THAN PREVIOUSLY FORECAST...WHICH HAVE BEEN UPDATED. ALSO NOTED THAT LOW CLOUDS HAVE WORKED INTO NYC AREA AND ACROSS LONG ISLAND WITH THE LIGHT S-SE WINDS THERE AT 03Z. WITH LIGHT/VRBL OR CALM WINDS ACROSS MOST OF THE REGION...SHOULD KEEP LOW CLOUDS AND PATCHY FOG FROM DEVELOPING UNTIL AFTER 06Z ALONG THE S COAST WITH THE ONSHORE WINDS AND TEMP/DEWPT SPREADS LOWER. PATCHY FOG WILL ALSO DEVELOP FURTHER INLAND WITH THE HIGHER DEWPTS...BUT WILL PROBABLY HOLD OFF UNTIL AROUND SUNRISE FOR A FEW HOURS ESPECIALLY WHERE WINDS BECOME CALM. HAVE UPDATED REMAINING NEAR TERM FORECAST TO BRING CONDITIONS CURRENT. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... TUESDAY INTO TUESDAY NIGHT... WARM FRONT WILL LIFT NORTHWARD TOMORROW PUTTING SOUTHERN NEW ENGLAND INTO A THE WARM/MOIST AIRMASS. A WEAK SHORTWAVE ALOFT WILL TRIGGER A FEW SCT SHOWERS WILL DEVELOP ACROSS THE REGION AFTER 11 AM LASTING INTO THE EVENING HOURS. MU CAPE VALUES COULD INCREASE TO 1500 J/KG AND WITH 20-30 KT SHEAR COULD SEE SOME STRONG STORMS. HAVE A VERY LOW CONFIDENCE ON IF ANY WOULD BE COME SEVER. LIMITING FACTOR IS THE LAPSE RATES AND THE CLOUD COVER...WHICH WOULD LIMIT THE AMOUNT OF INSTABILITY THAT COULD DEVELOP. YET PWAT VALUES ARE OVER 1.5 INCHES AND WITH WARM RAIN CORE PROCESSES...COULD SEE SOME HEAVY DOWNPOURS WITH PERHAPS URBAN/POOR DRAINAGE FLOODING. AS 850 MB TEMPS WARM TO 16C AND WITH DEWPOINTS REACHING CLOSE TO 70F...ANTICIPATE A WARM/MUGGY DAY. CONVECTION WILL BEGIN TO WIND DOWN BY THE EVENING HOURS AS HEATING IS LOST AND WE ARE ON THE BACKSIDE OF THE SHORTWAVE. SOUTHWESTERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL KEEP THE REGION IN WARM/MOIST FLOW. THIS WILL ALLOW FOR FOG TO DEVELOP ESP ALONG THE SOUTH COAST. OVERNIGHT TEMPS WILL WILL BE MILD WITH SEVERAL PLACES ONLY DROPPING INTO THE LOW 70S. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... BIG PICTURE... UPPER HIGH PRESSURE REMAINS IN CONTROL OVER THE ATLANTIC COAST WHILE LOW PRESSURE DIGS OVER THE WESTERN USA. JET FLOW FROM WESTERN CANADA RIDES ALONG THE US/CANADIAN BORDER. THE RIDGE SHIFTS TO THE MIDWEST AND PLAINS OVER THE WEEKEND MAKING ROOM FOR A TROUGH TO DIG OVER THE CANADIAN MARITIMES. UPPER HEIGHTS REMAIN AT OR ABOVE SEASONAL NORMALS THROUGH THE PERIOD. THIS SUGGESTS NORMAL SUMMER TEMPERATURES...ALTHOUGH DAYTIME HIGHS WILL OF COURSE BE HELD BACK ON DAYS OF HEAVY SKY COVER OR STRONG EAST FLOW. THE DAILIES... WEDNESDAY NIGHT-THURSDAY...MODERATE CONFIDENCE. COLD FRONT IN SOUTHEAST NEW ENGLAND DURING THE EVENING MOVES OFFSHORE BEFORE MIDNIGHT. THE FRONT THEN BECOMES ALIGNED WITH THE UPPER FLOW AND STALLS SOUTH OF THE REGION. SHORTWAVE IN THE UPPER FLOW MOVES THROUGH DURING THURSDAY...GENERATING A WAVE ALONG THE FRONT AND MAINTAINING A RISK OF SHOWERS THURSDAY. THE BEST CHANCE WILL BE SOUTH OF THE MASS PIKE NEAREST THE WAVE AND THE FRONT. PRECIPITABLE WATER VALUES REMAIN HIGH NEAR THE SOUTH COAST...SO LOCALLY HEAVY DOWNPOURS WILL CONTINUE TO BE A CONCERN IN SOUTHERN AREAS. CLOUDS AND A LIGHT EAST FLOW SHOULD KEEP DAYTIME TEMPS IN THE 70S. FRIDAY-SATURDAY...MODERATE TO HIGH CONFIDENCE. HIGH PRESSURE BUILDS OVER THE REGION WITH CLEARING SKIES AND LIGHT WINDS. MIXING SHOULD REACH TO AT LEAST 850 MB AND POSSIBLY TO 800 MB. TEMPS AT THESE LEVELS WOULD SUPPORT MAX TEMPS OF 80-85 FRIDAY AND MID 80S SATURDAY. DEW POINTS 55 TO 65 AND LIGHT WINDS SUGGEST MIN TEMPS IN THE SAME RANGE AS WELL AS PATCHY FOG. SUNDAY-MONDAY...LOW CONFIDENCE. CHANGES IN THE OPERATIONAL MODEL SOLUTIONS REGARDING MOISTURE IN THE VERTICAL ACTS TO SUPPRESS PCPN IN SOUTHERN NEW ENGLAND DURING THIS PERIOD. MEANWHILE A SHORTWAVE SWINGS ACROSS NORTHERN NEW ENGLAND INTO THE MARITIMES...PUSHING A COLD FRONT THROUGH OUR AREA. IT IS HARD TO TOTALLY KILL OFF POPS WHILE SUCH A MECHANISM IS IN PLACE. WE WILL MAINTAIN CHANCE POPS FOR THE MOMENT AND AWAIT FUTURE MODEL RUNS. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY NIGHT/... OVERNIGHT...MODERATE CONFIDENCE. VFR. MAY SEE MVFR-IFR CIGS AND/OR VSBYS ALONG S COASTAL AROUND OR AFTER 06Z. PATCHY FOG WITH MVFR CIGS/VSBYS MAY DEVELOP AROUND 07Z- 09Z FURTHER INLAND...UP TO MID CT VALLEY AND ACROSS S CENTRAL MA/RI/SE MA. LIGHT S-SE WINDS. TUESDAY...HIGH CONFIDENCE. MVFR-IFR CIGS AND ANY FOG LIFT TO HIGH-END MVFR / LOW-END VFR. -SHRA/-TSRA DEVELOPING OVER W/SW-TERMINALS BY AFTERNOON. SEA- BREEZES DURING THE MORNING WILL ERODE WITH INCREASING S-WINDS GUSTING UP TO 25 KTS POSSIBLE ALONG THE S-COAST. TUESDAY NIGHT...MODERATE CONFIDENCE. CONDITIONS POSSIBLY DROPPING BACK TO MVFR-IFR ALONG WITH THE POTENTIAL FOR PATCHY FOG. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA-BREEZE DURING THE MORNING WILL ERODE BY AFTERNOON TUESDAY PER INCREASING S-WINDS. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. PATCHY FOG IS POSSIBLE TONIGHT. LOW RISK OF A -TSRA TOMORROW AFTERNOON. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WEDNESDAY NIGHT-THURSDAY...MODERATE CONFIDENCE. A COLD FRONT OVER SOUTHEAST MASS/RI IN THE EVENING MOVES OFFSHORE WITH WINDS BECOMING NORTH OVERNIGHT AND NORTHEAST THURSDAY BUT WITH SPEEDS BELOW 15 KNOTS. SHOWERS MOVING UP THE FRONT THURSDAY WILL BRING AREAS OF MVFR CIGS/VSBYS WITH THE BEST CHANCE IN CT-RI AND SOUTHEAST MASS. FRIDAY-SATURDAY...MODERATE-HIGH CONFIDENCE. HIGH PRESSURE BRINGS CLEARING SKIES. VFR. AREAS OF IFR POSSIBLE IN EARLY MORNING FOG. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM /THROUGH TUESDAY NIGHT/...HIGH CONFIDENCE. 11 PM UPDATE... WINDS AND SEAS BELOW SMALL CRAFT CRITERIA OVERNIGHT. PATCHY FOG POSSIBLE ACROSS THE SOUTHERN WATERS WITH LOCALLY REDUCED VSBYS. SEAS WILL BEGIN TO BUILD TUESDAY AS A WARM FRONT MOVES N. COULD SEE SOME LOW END SCA DURING THE AFTERNOON WITH SOUTHERLY WIND GUSTS NEAR 25 KTS AND SEAS 4-5 FT. ALTHOUGH MARGINAL...FELT IT WAS BEST DUE TO ALL OF THE RECREATIONAL BOATERS ACROSS THE WATERS THIS WEEK. AFTER SUNSET...S WINDS WILL DIE DOWN BUT COULD SEE A CHOP ALONG THE WATERS OVERNIGHT. PATCHY DENSE FOG COULD ALSO REDEVELOP OVER THE WATERS. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... WINDS AND SEAS REMAIN BELOW SMALL CRAFT THRESHOLDS THROUGH THE PERIOD. A COLD FRONT MOVES OFFSHORE WEDNESDAY NIGHT AND STALLS OVER THE SOUTHERN WATERS. A DISTURBANCE MOVING ALONG THE FRONT WILL BRING SHOWERS AND SCATTERED TSTMS WEDNESDAY NIGHT/THURSDAY WITH REDUCED VSBYS IN ANY HEAVY DOWNPOURS. HIGH PRESSURE BRINGS FAIR WEATHER FRIDAY AND SATURDAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 10 PM EDT THIS EVENING FOR ANZ250. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM EDT THIS EVENING FOR ANZ231-251. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM EDT THIS EVENING FOR ANZ230. && $$ SYNOPSIS...WTB/DUNTEN NEAR TERM...EVT SHORT TERM...DUNTEN LONG TERM...WTB AVIATION...WTB/DUNTEN MARINE...WTB/DUNTEN/EVT

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