Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 031926 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 326 PM EDT FRI JUL 3 2015 .SYNOPSIS... HIGH PRESSURE OVER SOUTHERN NEW ENGLAND WILL SHIFT OFFSHORE OVERNIGHT. LOW PRESSURE RACES SOUTH OF NEW ENGLAND ON JULY 4TH AND MAY BRINGING SOME LIGHT RAIN TO SOUTH COASTAL AREAS. HIGH PRESSURE RETURNS SUNDAY AND LINGERS THROUGH EARLY WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... THROUGH 8 PM... HIGH PRESSURE OVER THE REGION. MOSTLY CLEAR SKIES AND LIGHT WIND SHOULD PROVIDE A FINE EVENING FOR OUTDOOR ACTIVITIES. TONIGHT... HIGH PRESSURE SHIFTS EAST BUT REMAINS IN CONTROL. SOUTHWEST FLOW ALOFT WILL BRING INCREASING MOISTURE IN THE FORM OF INCREASING CLOUDS ABOVE 10 THOUSAND FEET. SATELLITE SHOWS THESE HIGH CLOUDS OVER SOUTHWEST PA MOVING NORTHEAST...WITH A TREND TO REACH OUR AREA AFTER MIDNIGHT WHICH MATCHES WELL WITH GUIDENCE. FAIR SKIES THIS EVENING SHOULD ALLOW TEMPS TO COOL OFF QUICKLY. MEANWHILE DEW POINTS WILL CLIMB INTO THE 50S EVERYWHERE. THIS POINTS TO MIN SFC TEMPS IN THE 50S AND AROUND 60. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... INDEPENDENCE DAY... LOW PRESSURE ALONG THE MID ATLANTIC COAST RACES SOUTH OF OUR AREA ON SATURDAY. THE LOW WILL BE SUPPORTED BY AN UPPER SHORTWAVE MODEL FORECASTS HAVE BEEN BOUNCING AROUND THE PAST 24 HOURS REGARDING THE HANDLING OF COASTAL LOW THAT PASSES SOUTH OF NEW ENGLAND SATURDAY. GFS IS MOST AGGRESSIVE IN BRINGING PCPN ACROSS ALL OF SRN NEW ENGLAND WHILE THE NAM AND GGEM CLIP CAPE COD AND ISLANDS. THE ECMWF COMPROMISES WITH PCPN ACROSS RI AND SE MASS. WE FAVORED THE ECMWF PLACEMENT IN SETTING UP OUR POPS...LIKELY POPS ON THE CAPE/ISLANDS/SOUTH COAST...CHANCE POPS IN SE MASS/RI/NE CT...SLIGHT CHANCE NE MASS AND NCENTRAL MASS. CONVECTION FROM NEW YORK MAY CROSS INTO WESTERN MASS DURING THE AFTERNOON SO WE HAVE CHANCE POPS IN WESTERN MASS. SATURDAY NIGHT... THE COASTAL LOW CROSSES 40N/70W IN THE EVENING AND MOVES SOUTH OF NOVA SCOTIA OVERNIGHT. THIS SHOULD BRING ANY PCPN TO AN END DURING THE EARLY PART OF THE NIGHT. THE SUPPORTING UPPER TROUGH MOVES EAST OF US BY MORNING. THIS SHOULD BRING A CLEARING TREND AFTER MIDNIGHT WITH WINDS TURNING NORTHWEST. && .LONG TERM /SUNDAY THROUGH FRIDAY/... HIGHLIGHTS... * HIGH PRESSURE AND WARMING CONDITIONS INTO EARLY NEXT WEEK. * UNSETTLED CONDITIONS RETURN MID-LATE NEXT WEEK. OVERVIEW AND MODEL PREFERENCES...THE MOST RECENT GFS OPERATIONAL GFS REMAINS THE MORE AMPLIFIED OUTLIER IN THE SHORT TERM WITH THE DEEPENING OF A SHORTWAVE AND LOW PRES DEVELOPMENT THIS WEEKEND. THIS OVERAMPLIFCATION CONTINUES BEYOND THE WEEKEND LOOKING AT THE SYNOPTIC PATTERN. THEREFORE...WILL BE LEANING AWAY FROM THE GFS WITH THIS LONG TERM UPDATE AND APPLYING A BLEND OF THE GEFS/ECENS AND PERSISTENCE WITH THE OPERATIONAL ECMWF. A NEAR ZONAL FLOW PATTERN WILL SLOWLY GIVE WAY TO A BUILDING RIDGE ACROSS THE NE...AS DEEPENING CUTOFF ACROSS THE CANADIAN PRAIRIE CONTINUOUSLY FEEDS WARM ADVECTION INTO THE RIDGE. THEREFORE...THE MODERATING TEMPERATURE/DRY WX PATTERN WE HAVE BEEN ADVERTISING FOR EARLY NEXT WEEK STILL LOOKS LIKE A GOOD STARTING POINT. BY MID TO LATE NEXT WEEK...IT IS A MATTER OF THE INFLUENCE OF THIS CUTOFF. THERE IS SOME SUGGESTION OF A MORE E SHIFT IN THE CUTOFF...WHICH WOULD SUGGEST A LONGER UNSETTLED PERIOD. WHILE OTHERS ARE FURTHER W...AND SRN NEW ENGLAND REMAINS IN THE ZONAL FLOW WITHIN THE SE QUADRANT OF THE CUTOFF. IN ANY CASE...COOLER AND MORE PERIODIC WET WX IS POSSIBLE IN COMPARISON TO THE EARLY WEEK. DETAILS... SUN...A WEAK COLD FRONTAL PASSES ON SUN. OVERALL PWATS IN THE COLUMN ARE NEAR SEASONAL NORMALS AND THERE IS A FAIR AMOUNT OF DRY AIR WITH IN THE LOWEST 300HPA. AN ISOLATED SHOWER IS LIKELY TO BE MOST RAINFALL TO CONTEND WITH. H85 TEMPS NEAR +10C SUGGEST TEMPS NEAR NORMAL...SO HIGHS ON SUN REMAIN IN THE UPPER 70S TO LOW 80S. MON INTO TUE...WITH UPPER LVL RIDGE BUILDING OVER FROM THE W...COMBINING WITH THE BERMUDA HIGH...EXPECT HIGH PRES AND DRY WX TO PREVAIL. TEMPS WILL BE WARMING THROUGH THEE PERIOD...ALONG WITH RISING HUMIDITY. H85 TEMPS ARE CLOSER TO +15C BY TUE. THEREFORE...HIGHS RANGING IN THE 80S WILL BE FORECAST. WED...THE FIRST IN A SERIES OF WAVES EJECTING FROM THE STRONG CUTOFF WELL TO THE W WILL MOVE ACROSS THE REGION. INCREASING COLUMN MOISTURE WITH PWATS APPROACHING 2.0 STD DEVIATIONS ABOVE NORMAL...COOLING H5 TEMPS AND LEFTOVER WARM/MOIST LOWER LEVELS SUGGEST DECREASING STATIC STABILITY. THEREFORE...WITH THE WAVE AND ATTENDANT COLD FRONT...COULD SEE DEVELOPMENT OF T-STORMS AND SHOWERS. SHEAR IS NOT TOO STRONG AT THIS POINT...BUT WILL LIKELY NEED TO MONITOR THIS AS WE GET CLOSER. THU AND FRI...UNCERTAINTY REMAINS HIGH DURING THIS PERIOD AS IT WILL DEPEND ON HOW CLOSE THE UPPER CUTOFF GETS TO THE NE CONUS. THE FRONT WILL STALL IN THE VICINITY AND PROVIDE A FOCUS...BUT EXACTLY HOW MANY WAVE/HOW STRONG AND WHEN THEY OCCUR WILL HAVE TO BE BETTER DEFINED ONCE THE CUTOFF DEVELOPS AND BECOMES BETTER SAMPLED. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM /THROUGH FRIDAY NIGHT/... THIS AFTERNOON...HIGH CONFIDENCE. VFR. SEA BREEZES ALONG THE COAST. TONIGHT...HIGH CONFIDENCE. VFR. SATURDAY...MODERATE CONFIDENCE. VFR TO START. MVFR POSSIBLE IN SCATTERED AREAS OF LIGHT RAIN LATE IN THE DAY...BEST CHANCE IS AT TERMINALS ALONG THE SOUTH COAST. WE ARE MONITORING THE POSSIBILITY OF LOW CONDITIONS AT BOSTON TOWARD EVENING DEPENDING ON THE STRENGTH OF DEVELOPING EAST/NORTHEAST FLOW AT THAT TIME. SATURDAY NIGHT...MODERATE TO HIGH CONFIDENCE. RAIN OVER SOUTHEAST MASS/RI SHOULD TAPER OFF DURING THE FIRST PART OF THE NIGHT. MVFR CONDITIONS POSSIBLE IN ANY AREAS OF RAIN/FOG...OTHERWISE VFR WITH CLOUD BASES LIFTING/CLEARING OVERNIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK /SUNDAY THROUGH TUESDAY/... MON INTO TUE...HIGH CONFIDENCE. MAINLY VFR. A FEW SHOWERS OR THUNDERSTORMS POSSIBLE ON TUE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE TONIGHT...MODERATE CONFIDENCE SATURDAY AND SATURDAY NIGHT. TONIGHT... HIGH PRESSURE OVER THE REGION MOVES EAST OF THE WATERS BY SATURDAY MORNING. EXPECT LIGHT WINDS AND DIMINISHING SEAS. SATURDAY... LOW PRESSURE DEVELOPING ALONG THE MID ATLANTIC COAST WILL PASS OVER OR SOUTH OF THE SOUTHERN OUTER WATERS SATURDAY AFTERNOON AND EVENING. THIS WILL BRING LOWER VSBYS IN RAIN TO THE SOUTHERN WATERS WITH EAST WINDS INCREASING TO 15-20 KNOTS. FARTHER NORTH THE WINDS WILL BECOME EAST BUT AT LIGHTER SPEEDS. SATURDAY NIGHT...PERSISTANT EAST TO NORTHEAST WINDS WILL BUILD SEAS TO 5 FEET ON THE SOUTHERN OUTER WATERS. THIS MAY EVENTUALLY REQUIRE A SMALL CRAFT ADVISORY ON THOSE WATERS. AS THE LOW PRESSURE AREA MOVES OFF TO THE EAST THE WINDS WILL DIMINISH AND TURN NORTH OVERNIGHT. OUTLOOK /SATURDAY NIGHT THROUGH TUESDAY/... SUN...MODERATE CONFIDENCE. SEAS S AND SE OF NEW ENGLAND WILL SLOWLY DECLINE FROM 5-7 FT TO BELOW SMALL CRAFT ADVISORY CONDITIONS. THEREFORE...SMALL CRAFT ADVISORIES MAY LINGER THROUGH THE DAY ON SUN. SUN NIGHT INTO MON NIGHT...HIGH CONFIDENCE. HIGH PRES YIELDS MAINLY QUIET BOATING WEATHER. TUE...MODERATE CONFIDENCE. WINDS SHIFT TO THE S...AND WHILE QUIET BOATING WEATHER IS LIKELY TO DOMINATE...THERE IS A LOW CHANCE THAT INCREASING SEAS AND WINDS WILL APPROACH SMALL CRAFT ADVISORY THRESHOLDS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...WTB/DOODY NEAR TERM...WTB/DOODY SHORT TERM...WTB LONG TERM...DOODY AVIATION...WTB/DOODY MARINE...WTB/DOODY

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