Area Forecast Discussion
Issued by NWS Boston, MA

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607 FXUS61 KBOX 271423 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 1023 AM EDT SAT AUG 27 2016 .SYNOPSIS... High pressure builds over Northern New England, bringing dry weather for much of this weekend. A cold front will bring the threat for showers and thunderstorms Sunday night into Monday. Weak high pressure brings dry and mild conditions on Tuesday, followed by another cold front for mid week. This will bring another chance for showers and thunderstorms. Large high pressure from north central Canada will likely bring dry conditions and more seasonable temperatures by late this week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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High pressure is in place over the Northeast USA with center over Quebec. Aside from some patchy cirrus, Southern New England skies are sunny and should remain that way through the evening. Dew points should remain in the mostly comfortable upper 50s/low 60s. Late morning temps were in the mid 70s to lower 80s, a couple of degrees warmer than forecast. Based on the 10 am values, we have inched the max temp forecast up a couple of degrees with values in the upper 80s and low 90s inland. A northeast to east wind along the Mass east coast may keep temps near that shore a few degrees cooler than the interior.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... The center of the high pressure shifts east tonight into Sunday. Expecting mainly clear skies and light winds to prevail through this portion of the forecast. Once the high pressure reaches the Maritimes late Sunday, there is a small possibility for a mid level shortwave to bring isolated showers to northwest MA late in the day. Temperatures expected to be slightly above normal, despite seabreezes along both coasts Sunday. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Highlights... * Scattered showers and thunderstorms possible Sunday night into Monday * Dry and mild conditions briefly return Tuesday * Another cold front brings the chance for brief wet weather Tuesday night into Wednesday * Large high pressure sweeps out of north central Canada with more dry conditions and near seasonable temperatures late this week Overview and model preferences... Medium range model and ensemble suite continues to signal generally warm conditions with brief periods of showers/ thunderstorms across the northern tier states with weak mid level short waves in the nearly zonal steering flow through mid week. All models showing changes working into the overall North American flow as high amplitude ridge builds into north central Canada, across Nunavut and the NW Territories toward the Arctic Circle by mid week. This will bring a NW flow aloft into the northeast U.S. Large surface high pressure will shift SE late this week out of central Canada with more dry conditions as temperatures become seasonal. Only noting two weak fronts that will cross the region, with just a few showers and/or thunderstorms, so the long term dryness looks to continue into the holiday weekend. Used a blend of available guidance through Wednesday as models did show pretty good continuity, then blended over to ensemble guidance with the pattern change noted later this week though the 00Z operations runs of the GFS, GGEM and ECMWF remain in rather good agreement with the evolving North American pattern. Details... Sunday night-Monday...High pressure moves offshore with a SW wind flow in place at the surface and aloft. Cold front works SE, bringing the chance for showers/thunderstorms, with the best shot across N Mass around the Route 2 region, possibly as far south as the Mass Pike through Sunday night into Monday morning. As the front moves across the region, the H5 short wave associated with it pushes quickly E by midday Monday. With the lack of energy as well as limited moisture, the precipitation weakens as it shifts SE. The front continues to slowly cross the region, but as a dry passage. Winds shift to W-NW during Monday afternoon as skies become partly cloudy. Warm air lingers across the region, with highs mainly in the lower-mid 80s, with a couple of spots possibly touching 90. Tuesday...As the front pushes offshore, it stalls south of the region early Tuesday. Weak high pressure will build across, so expect another dry day. Temperatures remain mild, though, but dewpts do drop a few degrees so it will be less humid. Tuesday night-Wednesday...Another front will bring a few showers/ thunderstorms late Tuesday night and Wednesday. The front will steadily move through, pushing offshore Wednesday night. Will see best shot for precipitation across the CT valley to the E slopes of the Berkshires. Temperatures will continue to run above seasonal normals. Thursday night-Friday...Expect dry conditions as large high pressure works southeastward out of north central Canada to the Great Lakes during this timeframe. Temperatures will slowly lower to near or even below seasonal normals by Friday. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
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Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Sunday/... This afternoon...High Confidence. VFR. Light N-NE winds. Sea breezes will develop along both coasts. Tonight...High Confidence. VFR. Light and variable wind. Patchy fog after midnight in the usually prone locations, mainly in the CT River Valley, with IFR/LIFR cigs/vsbys through sunrise. Sunday... VFR with winds turning S and increasing. Increasing mid and high clouds across the region, with the possibility of a few SHRA N/W late in the day. KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF. Outlook /Sunday Night through Wednesday/... Sunday night...Moderate confidence. Mainly VFR. May see patchy MVFR conditions in widely scattered -SHRA/-TSRA mainly near and N of the Mass Pike, best chance near and N of Route 2. Patchy fog with local MVFR-IFR VSBYs after midnight. Monday...Moderate to high confidence. Mainly VFR. Slight chance of SHRA/TSRA over central and N Mass through midday. W winds shift to NW, may gust up to 20 kt on the S coast. Tuesday...Moderate to high confidence. VFR. Light W-NW winds back to SW as high pressure shifts S of the region. Tuesday night-Wednesday...Moderate confidence. Mainly VFR. Local MVFR-IFR in scattered SHRA/isolated TSRA. SW winds gusting to 15-20 kt along S coast, shifting to W-NW Wednesday night.
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&& .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Sunday/...High confidence. Winds and seas expected to remain relatively light through Sunday. Sea breezes near shore expected both today and Sunday. Seas increase across the outer coastal waters Sunday in response to arriving southeast swell from distant Tropical Storm Gaston. Outlook /Sunday Night through Wednesday/... Sunday night...High confidence. High pressure pushes offshore. Expect S-SW winds gusting to 20 kt across the eastern outer waters. Seas will remain below 5 ft, but may see a few higher swells on the eastern outer waters due to Gaston. Scattered showers/thunderstorms from Cape Cod northward with local visibility restrictions, along with patchy fog after midnight. Monday...Moderate to high confidence. SW winds shift to NW as cold front passes. Gusts up to 20 kt on the eastern outer waters Monday afternoon/evening. May see isolated showers/thunderstorms across the northern waters into Monday afternoon with brief visibility restrictions. Monday night-Tuesday...High confidence. NW winds shift to NE on Tuesday as high pressure builds across. SE Swells up to 5-6 feet reach the outer waters from Gaston. Tuesday night-Wednesday...Moderate confidence. Winds shift to S-SW as cold front approaches. Gusts up to 20 kt possible on the eastern outer waters Wednesday afternoon. May see local visibility restrictions Wednesday afternoon in isolated showers/ thunderstorms. Leftover 5 foot swells early Tuesday night will subside after midnight. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Belk/EVT NEAR TERM...WTB/EVT SHORT TERM...Belk LONG TERM...EVT AVIATION...Belk/EVT MARINE...Belk/EVT is the U.S. government's official web portal to all federal, state and local government web resources and services.