Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 181019 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 429 AM EST Sun Feb 18 2018 .SYNOPSIS... The snow quickly ends from west to east early this morning followed by rapidly improving conditions as temperatures rise well above freezing today. A warm front will then likely bring a period of showers late Monday and/or Monday night. This will set the stage for potentially near record high temperatures Tuesday and particularly Wednesday. A cold frontal passage will bring cooler temperatures late in the week along with the potential for some unsettled weather. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Back edge of the precipitation appears to be moving into portions of the CT valley on latest NE regional 88D radar imagery. Noting leftover -SN to KOXC-KHVN and northeastward on 09Z observations, with dry conditions S and W of there. As intensifying low pressure quickly pushes E to the Gulf of Maine, the precip shield will push offshore by mid morning. NW low level jet crosses the region this morning, so will likely see wind gusts up to 20-30 kt, highest along the immediate coast and higher inland terrain. This should not last long, probably through about midday, then will diminish. Skies should become mostly sunny by midday as well, except for some clouds that may linger a bit longer along the coast. Not a lot of cold air associated with this system as the mid level flow remains nearly zonal. So, expect temps to top off in the 35-40 degree range across the higher terrain, ranging to the mid 40s across the coastal plain. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... Tonight... Large high pressure will build E toward the region. This will bring mostly clear skies through around midnight, then may see some clouds push in as light NW winds shift to S during the night. Expect overnight lows mainly in the 20s, except 30-35 along the immediate S coast. With the dropping temps, any standing water from the snow melt may form into black ice on untreated surfaces. && .LONG TERM /MONDAY THROUGH SATURDAY/...
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Highlights... * Warm front likely brings a round of rain showers late Mon/Mon night * Near record breaking warmth possible Tue/Wed w/highest risk Wed * Cooler temperatures Thu/Fri/Sat with perhaps some unsettled weather Details... Monday and Monday night... Some morning sunshine will fade behind increasing cloudiness ahead of an approaching warm front. Enough forcing/lift will be available with this front for a round of rain showers late Mon/Mon night. High temps Mon will be well up into the 40s to near 50...but expect mainly steady or slowly rising temperatures Mon night with plenty of low clouds and increasing low level moisture. Areas of fog may also develop. Tuesday and Wednesday... Anomalous 594 decimeter upper level ridge off the southeast coast will set the stage for the potential of near record warmth Tue/Wed in southern New England. If enough sunshine is realized...high temperatures will soar well into the 60s away from the marine influence of the south coast/Cape/Islands Tue/Wed. In fact...model 2 meter temperature guidance continues to indicate the potential for 70+ degree readings on Wed in some locations. With that said...there is one big fly in the ointment that could result in cooler temperatures than we are currently forecasting. Model cross sections indicate a fair amount of low clouds on Tue and possibly some on Wed. If low clouds do get in the way it still would be mild...but high temps would mainly be in the 50s. Greater concern for low clouds appears to be Tue...but can not rule them out Wed either especially near the south coast. Thursday/Friday/Saturday.... While the upper level ridge off the southeast coast will remain fairly strong...a 1040 mb surface high across eastern Canada and northern New England will force a cold front south of the region. This will result in cooler temps Thu/Fri/Sat...but still expect readings to average above normal. Will have to watch for a bit of ana frontal precipitation on Thu...but that is uncertain. A better chance for a period of precipitation exists sometime Fri and/or Sat...but low confidence on timing. Ptype favors liquid...although we can not rule out a bit of ice/snow if Canadian High Pressure hangs in a bit longer.
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&& .AVIATION /09Z SUNDAY THROUGH THURSDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tonight/... Through 12Z...High confidence. Areas of MVFR-IFR CIGS/VSBYS in -SN continue across most of the region at 09Z, except -RA across S RI/SE Mass where winds were light E-NE or calm. As back edge of precip shifts E, conditions should improve to VFR by 12Z, except may linger across E coastal areas. Winds shift to W-NW by 12Z, and may gust up to 20 kt across the E slopes of the Berkshires as well as across the S coastal islands. Today... Brief leftover MVFR-IFR CIGS through 13Z-14Z, then VFR. NW wind gusts up to 25-30 kt this morning, highest across higher inland terrain and along the coast, then diminish during the afternoon. Tonight... VFR. KBOS Terminal... MVFR-IFR conditions in -SN will improve to VFR by around 13Z as precip ends. W-NW wind gusts up to 20-25 kt this morning, then diminish during the afternoon. KBDL Terminal... MVFR-IFR conditions in -SN should improve to VFR by 12Z. NW wind gusts up to 20-25 kt this morning, then diminish by mid afternoon. Outlook /Monday through Thursday/...Moderate to High confidence. Washingtons Birthday: Mainly VFR, with local MVFR possible late. Breezy. Chance SHRA late. Monday Night: Mainly MVFR, with areas IFR possible. SHRA likely, patchy BR. Tuesday: MVFR with local IFR possible. Breezy. Patchy BR. Tuesday Night: MVFR/IFR conditions possible. Wednesday: Mainly VFR, with local MVFR possible. Wednesday Night through Thursday: Mainly VFR, with areas MVFR possible. Breezy. Chance SHRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tonight/... Through Today...Moderate confidence. Reduced visibility in areas of rain and snow should improve by midday as precipitation moves offshore. NW winds will gust up to 25-30 kt through midday, then will diminish. Seas will build up to 5-6 ft across the outer waters. Small Craft Advisories in effect for all waters through midday, then will slowly end as winds diminish, though may linger across the outer waters into this evening. Tonight...High confidence. Leftover 5 foot seas should subside across the outer waters by around 03Z, should Small Crafts should end. Otherwise, light W-NW winds will become S during the night. Good visibility. Outlook /Monday through Thursday/...Moderate to High confidence. Washingtons Birthday: Small Craft Advisory wind gusts possible mainly confined to our eastern outer waters. Areas of seas approaching 5 ft. Chance of rain showers. Monday Night: Low risk for Small Craft Advisory winds with local gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers, patchy fog. Local visibility 1 to 3 nm. Tuesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain showers, patchy fog. Local visibility 1 to 3 nm. Tuesday Night: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers. Wednesday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Slight chance of rain showers. 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. && .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...Winter Storm Warning until 7 AM EST this morning for CTZ002>004. MA...Winter Storm Warning until 7 AM EST this morning for MAZ005>007-011>019. Winter Weather Advisory until 7 AM EST this morning for MAZ002>004-008>010-026. RI...Winter Storm Warning until 7 AM EST this morning for RIZ001>006. MARINE...Small Craft Advisory from 7 AM this morning to 2 PM EST this afternoon for ANZ231>234. Small Craft Advisory from 8 AM this morning to 1 PM EST this afternoon for ANZ230. Small Craft Advisory from 7 AM this morning to noon EST today for ANZ236. Small Craft Advisory from 7 AM this morning to 1 PM EST this afternoon for ANZ235-237. Small Craft Advisory until 6 PM EST this evening for ANZ250- 256. Small Craft Advisory until 1 PM EST this afternoon for ANZ251. Small Craft Advisory until 10 PM EST this evening for ANZ254- 255. && $$ SYNOPSIS...EVT/Frank NEAR TERM...EVT SHORT TERM...EVT LONG TERM...Frank AVIATION...EVT/Frank MARINE...EVT/Frank CLIMATE...Staff

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