Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
844 FXUS61 KBOX 150815 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 415 AM EDT Tue Aug 15 2017 .SYNOPSIS...
-- Changed Discussion --
Showers lingers today, with a stray thunderstorm possible before improvement arrives again tomorrow night. High pressure brings fair weather Wednesday and Thursday. A weather system from the Plains will bring showers and scattered thunder Friday and Saturday. High pressure returns with fair weather Sunday and Monday.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Today...High confidence. A soupy morning is shaping up across the region as southerly flow continues to increase the low level moisture. Several locations across the Cape and the Islands are reporting fog less than a mile, which is also shown in webcams. Have contemplated about spreading the dense fog adv, but because rain is moving into the region, it may keep sites from falling below a half of a mile. Thus will hold off for now. Showers continue across southern CT and into portions of New England early this morning. This is in conjunction with stalled stationary boundary south of the region, weak WAA and upper level jet streak. As the jet streak continues to move across the region, expect showers to become more widespread resulting in precip lingering into the morning commute. This is suggested by the latest few runs of the HRRR which seems to be on the right track per current conditions. An increase in mid-level moisture while a weak shortwave rides along the front will also aid in the shower development. Showers will become more scattered in nature by mid-morning but still lingering thanks to the near by boundary and increasing low level moisture. Another shortwave will ride along the front during the afternoon hours. Guidance is hinting that these will be more widespread and clip the south coast resulting in likely precip across the Cape and the Islands. Def not turning into a nice beach day today. Because of the focus on precip across the south, the potential for a few strong thunderstorms seems to be unlikely at this time. Potent shortwave across the Great Lakes will bring a few strong storms across northern New England. Because of the precip potential across the south coast, cloud cover will be dense today. This will limit heating and thus anticipate highs only in the upper 70s and keep Cape values low. Mid-level moisture as indicated by the K values will also drop this afternoon away from the south coast. Thus limiting any strong thunderstorm potential. Can`t rule out one across NW MA closer to the northern shortwave and steeper lapse rates, but overall threat is low. Lastly, QPF amounts will generally be light today, but with PWAT values reaching above 1.5 to 2 inches south of the Pike, may need to watch for nuisance flooding.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
-- Changed Discussion --
Tonight into Tomorrow... High confidence. Upper level trough will swing through the region tonight as High pressure to the west begins to build. Still plenty of low level moisture around so another night of stratus and fog will be on deck. This is shown in BUFKIT cross sections, especially across the south coast and CT valley. Conditions will improve once surface cold front swings through the area and winds switch to a more westerly direction bringing in drier air. High pressure will build on Wednesday resulting in mostly sunny skies and temperatures warming back into the 80s. Beach Forecast: One thing to watch is the high surf and rip current threat from Hurricane Gerth. Swells up to 7 feet are expected to approach the region late tonight into tomorrow morning. This combined with a period of 14 sec and waves above 5-8 feet will result in a life-threatening conditions for all people who enter the surf from dangerous rip currents and high surf. Because of this, went ahead and issued a high surf adv for Wednesday. Use caution if heading to the beach.
-- End Changed Discussion --
&& .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Big Picture... Subtropical high remains in control across the Southern USA while a general zonal flow continues across Canada and the Northern USA. A series of shortwave ridges and troughs will move through this flow. A closed low over Quebec and cyclonic flow over New England all shift east Wednesday night. Multiple shortwaves move through New England Friday through Sunday. Model mass and thermal fields from the 00Z suite are in general agreement through Friday. They are then similar in general through the weekend but show differences in details. Run-to-run consistancy has had problems the past few days, which tempers confidence especially for the end of week system. Details... Wednesday night and Thursday... High confidence. Shortwave ridge moves over the region with dry air through most of the column. Light gradiant means light surface wind Wednesday night, which should allow a period of radiational cooling. Mid and high level moisture increases Thursday, especially afternoon/evening. Overall, a fair weather period. With radiational cooling expected, we nudged min temps down a couple of degrees Wednesday night. With temps aloft 12-14C, expect Thursday max temps in the upper 70s to mid 80s. Thursday night to Saturday... Moderate confidence. Next group of shortwaves moves through late in the week. First will be with the approaching warm front, second with the cold front, and a third trailing the second. Moisture builds in the column with PW values building to 2 inches Friday, then diminishing late Saturday as the cold front moves through. Stability parameters are mixed, with the Totals marginal, but the LI unstable. Looks like showers with some potential for thunder especially on Saturday. High dew points will contribute to areas of fog each overnight/morning. Sunday-Monday... Lingering instability Sunday as the third shortwave moves through. But moisture fields dry out Saturday night, which makes it hard to support any forecast of showers. High pressure builds later Sunday into Monday. Overall, a dry forecast with near seasonal temperatures. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Wednesday/... Before 12z...Moderate confidence. VFR away from the Cape and Islands, but many eastern terminals will drop to MVFR cigs by sunrise. LIFR conditions will continue across the Cape and Islands as IFR occurs along the south coast. Widespread showers across the region. Today...Moderate confidence. Lingering fog burns off after sunrise. Sct showers will continue until late this morning. Otherwise, VFR with a few showers and isolated T-storms mainly W MA during the afternoon. Weak sea breezes along the east coastline. Tonight...Moderate confidence. VFR gives way to another mix of IFR/MVFR mainly CT/RI and SE MA while the remainder stays mostly VFR, then as winds shift around to the W, transition back to VFR everywhere toward the morning. Wednesday...High confidence. VFR with dry weather. KBOS Terminal...Moderate confidence in TAF. Low probability for a few hours of MVFR conditions after 09z. KBDL Terminal...High confidence in TAF. Outlook /Wednesday Night through Saturday/... Moderate confidence. Wednesday night-Thursday... High confidence. VFR with light wind. Patches of fog are possible overnight and Thursday morning, especially in the usual fog spots. Thursday night through Saturday... Moderate confidence. VFR with areas of MVFR cigs/vsbys in showers and scattered thunderstorms. Lowest conditions are expected Friday night in areas of fog.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Wednesday/...High confidence. Today... S winds develop with gusts to around 20 kts on the E waters during the day, but brief. Otherwise seas will begin to build as swells from GERTH begin to approach the waters. Should remain below SCA until this evening. Otherwise widespread showers will impact the southern waters today. This evening and into tomorrow... A few showers will lingering but conditions will be improving. Still anticipate another round of fog tonight. Waves begin to reach above 5 feet across the southern waters as swells from GERTH increase. SCA has been issued for tonight and lasts into tomorrow as waves will reach between 5-8 feet with a southerly swell near 7 feet. Outlook /Wednesday Night through Saturday/... Moderate confidence. Winds less than 20 knots through the period, although gusty at times especially on Narragansett Bay Friday and Saturday. Lingering 5-6 foot seas on the southern waters Wednesday night, subsiding to less than 4 feet Thursday through Saturday. Areas of fog will bring reduced visibility most mornings. Showers and scattered thunder Friday and Saturday will also bring reduced visibility.
-- End Changed Discussion --
&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...High Surf Advisory from 9 AM to 8 PM EDT Wednesday for MAZ020- 022>024. Dense Fog Advisory until 10 AM EDT this morning for MAZ022>024. RI...High Surf Advisory from 9 AM to 8 PM EDT Wednesday for RIZ006>008. MARINE...Small Craft Advisory for hazardous seas from 11 PM this evening to 8 PM EDT Wednesday for ANZ235-237. Small Craft Advisory for hazardous seas from 7 PM this evening to 8 PM EDT Wednesday for ANZ255-256. && $$ SYNOPSIS...WTB/Dunten NEAR TERM...Dunten SHORT TERM...Dunten LONG TERM...WTB AVIATION...WTB/Dunten MARINE...WTB/Dunten

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