Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 190807 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 307 AM EST Mon Feb 19 2018 .SYNOPSIS... A warm front will likely bring a period of showers late today and tonight. This will set the stage for near record high temperatures Tuesday and especially Wednesday...so long as enough sunshine is realized. Cooler temperatures work into the region Thursday into the weekend...but still expecting them to remain above normal. Best chance for unsettled weather will be sometime Friday into next weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1240 AM Update... High pressure ridge slowly pushing E across the region early this morning, which should move off the coast by around 12Z. Veil of high thin cirrus continues to move E across the northeast U.S. as seen on latest GOES-East Air Mass RGB composite satellite loop. Noting mainly calm winds across the region on the 05Z observations so, even with the passing high clouds, temps were mainly in the 20s except a bit milder across the urban centers. With the temps below freezing, should see refreezing of any standing waters into black ice on untreated surfaces. Short range models continue to signal a warm bias vs. current conditions, so have adjusted downward. Beginning to see winds shift to SE-S across central and E NY state on the backside of the ridge so suspect that, once winds start to gradually increase from the S, temps should halt their fall and even rise a bit overnight. The question is when this will start. Will continue to monitor this aspect. Have updated to incorporate near term trends into the overnight forecast. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... Increasing south winds will boost temperatures well above normal Monday, and likely keep temperatures nearly steady or slowly rising Monday night. Morning sunshine. Increasing clouds during the afternoon as a warm front approaches. There appears to be enough forcing and moisture for a likely period of showers sometime late afternoon into Monday night. Chance for showers should decrease after midnight Tuesday as a warm front moves into northern New England. It should remain mostly cloudy, though. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Highlights... * Wednesday: Near all time February record highs might be approached if enough sunshine is realized * Cooler Thu/Fri into next weekend but temps still above normal * Unsettled weather possible sometime Friday into next weekend with ptype favoring rain although a bit of ice/snow can not be ruled out Details... Tuesday night... Massive southeast upper level ridge will result in an anomalous southwest flow of very mild air into southern New England. Low temps may not drop below 50 away from the cooler marine influence of the south coast. Some low clouds and fog are certainly possible...especially near the Cape/Islands with high dewpoint air moving over the relatively cool ocean. Wednesday... Anomalous upper level ridge of 594 decameters off the southeast coast will pump an incredibly mild airmass into our region for late February standards. This will result in 850T rising to between +12C and +14C. Given southwest flow...high temperatures will climb well into the 60s to lower 70s inland from the cooling marine influence of the southeast New England coast. If this ends up being the case...record highs would be broken and near all time February record high temperatures would be challenged. The one fly in the ointment is if we are jammed up in a bunch of low clouds. NAM soundings suggests this as a possibility...but often southwest flow is able to allow for these to break up. However...if the low clouds remain in place high temps would be cooler than currently forecast. Something later shifts will have to monitor closely. Wednesday night and Thursday... While the southeast upper level ridge will remain in place...1040+ MB surface high pressure system will approach from the west and force a cold front south of the region Wed night/Thu. The result will be significantly cooler temperatures Thursday with high temperatures mainly in the 40s. At this time...the bulk of the period looks dry but we can not rule out a period of mainly ana frontal showers which are depicted in some of the GEFS/EPS ensemble members. Friday through Sunday.... Low confidence forecast particularly with timing...but the potential exists for a couple rounds of unsettled weather Friday into next weekend. Certainly not expecting the entire period to be a washout...just impossible to try to time individual shortwaves this far out. The southeast ridge remains pretty strong...so ptype favors mainly rain. However...if a couple Canadian high pressure systems are slower to retreat it could be marginally cold enough to support a bit of snow/ice. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tuesday/...High confidence. Through 12Z...VFR. Light/variable or calm winds becoming light S after 08Z. Today...Mainly VFR. May see areas of MVFR CIGS/VSBYS push into central and western areas after 18Z in scattered showers. S winds gusting up to around 20 kt from late morning into mid afternoon. Tonight...Areas of MVFR CIGS/VSBYS in scattered -SHRA and patchy fog. Local IFR possible toward the south coast, including the Cape and islands. S winds gust up to 20 kt across Cape Cod and the islands. Tuesday...MVFR conditions in scattered -SHRA and patchy fog early improving to VFR. However, MVFR may linger along the S coast through early afternoon. KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF. Outlook /Tuesday Night through Friday/...Moderate confidence. Tuesday Night: MVFR/IFR conditions possible. Slight chance SHRA, patchy BR. Wednesday: Mainly VFR, with local IFR possible. Breezy. Slight chance SHRA. Wednesday Night through Thursday: Mainly VFR, with areas MVFR possible. Chance SHRA. Thursday Night: VFR. Friday: Areas of MVFR/IFR possible. Breezy. Chance RA with a low risk of some ice/snow across the interior. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tuesday/...High confidence. Through 12Z...Light/variable winds shift to S. Good visibility. Today into Tonight...Increasing S winds, resulting in build seas across the outer coastal waters. Small Craft Advisories will likely be needed across the outer coastal waters as well. Chance of rain showers. Patchy fog possible tonight with visibility of 1 to 3 nm. Outlook /Tuesday Night through Friday/...Moderate to High confidence. Tuesday Night: Winds less than 25 kt. Areas of rough seas. Slight chance of rain showers, patchy fog. Areas of visibility 1 to 3 nm. Wednesday: A period of southwest wind gusts of 20 to 25 knots possible with the strongest winds near shore. Areas of rough seas. Slight chance of rain showers, patchy fog. Local visibility 1 to 3 nm. Wednesday Night: Winds less than 25 kt. Local rough seas. Chance of rain showers. Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Thursday Night: Winds less than 25 kt. Friday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain. && .CLIMATE... Record Highest Observed Temperature for February... (since records began) Boston.........73 (02/24/2017) Hartford.......73 (02/24/1985) Providence.....72 (02/24/1985) Worcester......69 (02/24/2017) Record High Temperatures (Tuesday 20th / Wednesday 21st)... February.......20th......21st..... Boston.........68 (1930) 63 (1906) Hartford.......69 (1930) 63 (1930) Providence.....69 (1930) 63 (1930) Worcester......65 (1930) 59 (1930) Record Warmest Low Temperature... February.......20th......21st..... Boston.........46 (1930) 45 (1994) Hartford.......50 (1981) 49 (1981) Providence.....48 (1981) 50 (1981) Worcester......47 (1981) 43 (2002) && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 3 AM to 5 PM EST Tuesday for ANZ235- 237. Small Craft Advisory from 10 AM this morning to 5 PM EST Tuesday for ANZ250-254. Small Craft Advisory from 6 PM this evening to 5 PM EST Tuesday for ANZ255-256. && $$ SYNOPSIS...Frank NEAR TERM...WTB/EVT SHORT TERM...Belk LONG TERM...Frank AVIATION...EVT/Frank MARINE...EVT/Frank CLIMATE...Staff

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