Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | 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 301737 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 137 PM EDT THU JUN 30 2016 .SYNOPSIS... Dry but very warm weather is on tap for the region today. A cold front moves over the region on Friday into early Saturday, bringing a round or two of scattered showers and thunderstorms. High pressure builds in behind the front and prevails through the middle of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 AM update... Current forecast on track. Forecast soundings suggest some diurnal cu will develop but skies will be mostly sunny. Highs will reach well into the 80s with light winds, except cooler along the immediate coast where seabreezes develop. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... ***A few strong to severe thunderstorms possible late Friday into Friday night with localized heavy rainfall*** Tonight... High pressure moves off the coast, but dry and tranquil weather should prevail. Low temps will mainly be in the upper 50s and lower 60s, except middle to upper 60s in the urban heat island of Boston. Localized patchy ground fog may develop late in the typically prone locations. Friday... Approaching shortwave trough will allow a modest southerly low level jet to advect deeper moisture back into southern New England. Clouds should increase in the warm air advection pattern as the day wears on. There is a lot of uncertainty as to how quickly low level moisture will return and timing of the shortwave. Appears one shortwave will lift across NY state into northern New England, while a secondary wave lifts across southern New England late Fri into Fri night. The result of the shortwaves and height falls should allow the risk for scattered showers/thunderstorms to increase Friday afternoon into Friday night. The timing and amount of instability remains highly uncertain, but appears decent mid level lapse rates should result in a period of 1000+ J/kg of CAPE along with 0 to 6 km shear of 30 to 40 knots. So to sum up, we are fairly confident in a round or two of scattered showers/t-storms later Friday into Friday night. Instability/timing remain the biggest wild cards, but given decent mid-level lapse rates/height falls, there will be the risk for a few strong to severe thunderstorms. In addition, locally heavy rainfall will also be a possibility. Hopefully, later model guidance runs will come into better agreement on timing and amount of instability that we can expect. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGHLIGHTS... * Showers/thunderstorms linger into Friday night * Cooler temps Saturday, then increasing temps through next week * High pressure brings dry weather for much of next week Overview...Quiet pattern continues through next week starting with upper level ridging in the center of the country and upper troughs in the Pacific NW and the NE. The upper level pattern flattens out a bit by Monday with weak ridging continuing across the middle of the country. Models are in good agreement on the synoptic pattern and will use a blend of available guidance for this forecast. A cold front moves through southern New England Friday night with a few lingering showers and thunderstorms. Then high pressure builds into the region for the remainder of the holiday weekend. Low pressure passes south of southern New England Tuesday and Wednesday, but quiet weather will continue for the region. Temperatures...Aside from slightly cooler temperatures Saturday, behind the cold front, temperatures will gradually warm into next week. By the middle of next week, temperatures will be in the upper 80s to lower 90s. Precipitation...The only shot of rain in the long term forecast is showers and thunderstorms with the cold front Friday night. Timing of the front has sped up since last night, so expect the bulk of the storms to be Friday afternoon, then lingering into Friday night. Otherwise, looking at a dry forecast through the middle of next week. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --
Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Friday night/... Through Tonight...High confidence. VFR. Some localized patchy fog may develop late in the typically prone locations. Friday...Moderate confidence. Mainly VFR cigs. Scattered showers and t-storms developing in the afternoon, especially late in the day in western New England with brief lower conditions. Friday night...Moderate confidence. Areas of MVFR/IFR cigs possibly developing, especially east along with patchy fog. Showers and scattered t-storms likely moving across the region during the evening. KBOS Terminal...High confidence. KBDL Terminal...High confidence. Outlook /Saturday through Monday/... Saturday...High confidence. Any lingering MVFR conditions will improve to VFR quickly Saturday morning. Sunday and Monday...High confidence. VFR. Low probability of sea breezes developing each afternoon.
-- End Changed Discussion --
&& .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Friday/...High confidence. Winds and seas should remain below small craft advisory thresholds through the period, but do expect near shore southerly wind gusts around 20 knots to develop Friday afternoon. Otherwise, dense fog across our southeast waters should burn off later this morning. In addition, a few thunderstorms may affect the waters late Friday and Friday evening. Outlook /Friday Night through Monday/... High confidence. Mainly quiet boating weather expected. Winds and seas remain below SCA criteria throughout the period. However, they will increase as a cold front crosses over the coastal waters Friday night. This will result in showers and thunderstorms, which will reduce visibilities at times. && .FIRE WEATHER... Dry weather is expected today with very warm temperatures and humidity values dropping to 30 to 35 percent away from the coasts this afternoon. Winds will remain below 10 mph, however, precipitation was very spotty yesterday with many locations not getting any rain at all. Hit or miss showers and thunderstorms are possible Friday and Friday night. However, widespread precipitation looks to be nil over the next 7 days. High pressure and dry conditions appear to take hold of the region Saturday, lasting through the middle of next week. Specifics are still too hard to nail down, but it looks like the area will be less humid and a bit cooler but dry during this time frame. RH values could drop close to 30 percent between Sun into Wed. Winds overall appear to be light during this period. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Frank/RLG NEAR TERM...KJC SHORT TERM...Frank LONG TERM...RLG AVIATION...KJC/RLG MARINE...Frank/RLG FIRE WEATHER... is the U.S. government's official web portal to all federal, state and local government web resources and services.