Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 130750 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 250 AM EST Tue Feb 13 2018 .SYNOPSIS...
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High pressure brings dry but chilly weather to southern New England today. Unseasonably mild weather is anticipated Wednesday into Friday afternoon with scattered rain showers from time to time ahead of an approaching cold front. A brief shot of cold but dry weather follows Friday night into Saturday...but above normal temperatures return Sunday and especially by Monday.
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&& .NEAR TERM /UNTIL 6 AM THIS MORNING/... 10pm update... The combination of a modest pres gradient and some mid lvl moisture impinging on the sounding from Lake Effect moisture in NY state have kept both dwpts and temps from dropping off as quickly as much of the guidance suggests it should. Therefore, will adjust toward the raw 2m temps which are closest, but with some minor manual adjustments. Mins are a bit warmer than previous forecast, but still chilly, with most locations headed for the 20s by sunrise. Forecast on track otherwise. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... Tuesday... High pressure passes overhead, yielding strong subsidence and sunny/mostly sunny skies. As the high center shifts to the east of New England, winds become light from the S/SW. Some high clouds may start working into our area late in the day. Anticipating high temps mainly in the upper 20s to mid 30s. NW winds to start the day, then as high passes overhead winds become light and variable, then out of the SW later in the afternoon. Tuesday night... As the area of high pressure moves further offshore, warm air advection ensues in the return flow. Expect some increase in clouds overnight, which will limit extent of radiational cooling. Hence overnight lows should be a few degrees warmer than those from Mon night, going with mid teens to mid 20s. Winds light out of the S/SW. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
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Highlights... * Brief showers possible late Wed night/early Thu am, otherwise mainly dry with unseasonably mild temperatures Thu afternoon * Cold front likely brings some showers Thu night/Fri am followed by a brief shot of dry but cold weather Fri night/Sat * Above normal temps return Sun and especially Mon Details... Wednesday night and Thursday... Anomalous upper level ridging over the Gulf coast will result in unseasonably mild westerly flow across southern New England. We may have a brief round of showers late Wed night/early Thu with a burst of marginal elevated instability/moisture. The low level jet has mainly a westerly component...so uncertain if these brief showers will impact most of the area or pass to the south of most locations. Regardless...mainly dry weather anticipated by late Thu morning and afternoon. Given well mixed atmosphere and 850T between +2C and +4C...high temps should be well above normal. High temps will likely climb well into the 50s. However...if we end up with more sunshine than expected it is not out of the question that a few locations in the lower elevations could break 60! Thursday night and Friday... Weak wave of low pressure and approaching cold front will likely bring a period of showers to the region Thu night into Fri morning. Mild/above normal temperatures will continue over this time period. Temps should remain above freezing Thu night with highs well up into the 40s to lower 50s on Fri. Friday night and Saturday... Dry weather but a brief shot of cold air moves into the region behind the cold front. Low temps Fri night in the teens to lower 20s with highs Sat mainly in the 30s. Sunday and Monday... Upper level ridging builds across the southeast coast resulting in the return of unseasonably high height fields into southern New England. Above normal temperatures will return Sun and especially by Mon. The threat for showers will increase by Monday...but of course timing is highly uncertain in this time range.
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&& .AVIATION /08Z TUESDAY THROUGH SATURDAY/...
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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 Wednesday/...High confidence. Through tonight... Mainly VFR, although some SCT-BKN MVFR CIGS (020-030) could impact the outer Cape/Nantucket late this afternoon and evening. NW winds with a few gusts to around 20 kt across SE MA this morning. The winds then shift around to the S by evening. Wed... More clouds with CIGS gradually lowering to low VFR with occasional MVFR conditions from S-N. Winds mainly SSW around 10 kt. KBOS Terminal... High confidence in TAF. KBDL Terminal... High confidence in TAF. Outlook /Wednesday Night through Saturday/...Moderate Confidence. Wednesday Night: Mainly VFR, with local MVFR possible. Breezy. Chance SHRA, patchy BR. Thursday: Mainly VFR, with areas MVFR possible. Breezy. Thursday Night: Mainly MVFR, with local IFR possible. Chance SHRA. Friday: MVFR/IFR conditions possible. Windy with local gusts to 30 kt. Chance SHRA. Friday Night: VFR. Windy with areas gusts to 30 kt. Saturday: VFR. Breezy.
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&& .MARINE...
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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 Wednesday/...High confidence. Tonight... NW winds gust 20 to 25 kts. Seas will slowly diminish, but remain at 4 to 6 feet on the outer waters and RI waters. Small Craft headlines are in place for most waters for tonight. Tuesday... High pressure over the waters. North winds 10 to 15 kts becoming variable less than 10 kts. Seas up to 5 ft on the outer coastal waters E/S of Nantucket in the morning, subsiding below 5 ft during the day. Tuesday Night... Winds/seas below SCA thresholds, with winds becoming SW 10 to 20 kts. Outlook /Wednesday Night through Saturday/...Moderate to High Confidence. Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers, patchy fog. Local visibility 1 to 3 nm. Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Friday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Chance of rain showers. Friday Night: Low risk for gale force winds with gusts up to 35 kt. Rough seas up to 11 ft. Saturday: Winds less than 25 kt. Local rough seas.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 5 AM EST early this morning for ANZ231-251. Small Craft Advisory until 10 AM EST this morning for ANZ250. Small Craft Advisory until 1 PM EST this afternoon for ANZ254- 255. Small Craft Advisory until 7 AM EST this morning for ANZ256.
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&& $$ SYNOPSIS...NMB/Frank NEAR TERM...Doody SHORT TERM...NMB LONG TERM...Frank AVIATION...Doody/Frank MARINE...NMB/Sipprell/Frank

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