Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 180833 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 333 AM EST Sun Feb 18 2018 .SYNOPSIS...
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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.
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&& .NEAR TERM /UNTIL 6 AM THIS MORNING/... 1250 AM Update... KBOX 88D Dual Pol continues to show correlation coefficient (CC) values of around 0.8, indicative of wet snow and/or rain across SE RI and S coastal Massachusetts including the mid and lower Cape and Martha`s Vineyard. Also noting bright banding on the 0.5 degree reflectivity where the mixed precip lies. Temps in those areas ranged from 33 degrees from KPVD-KPYM, up to 39 degrees at KACK at 05Z where it continues to lightly rain. Winds have shifted back to light N across the CT Valley where temps remain in the upper 20s to near 30, while heavier snow was reported across N central and NE Mass down to the Route 128 where visibilities were between 1/2 and 1 mile. Noting snow amounts of 3-5 inches across N Central CT into NW RI on Public Information Statement at 1217 AM. With the mix and change over to rain across S coastal areas, have ended the the Winter Storm Warnings and Winter Weather Advisories across those areas. Noting back edge of precip working into SW CT, moving into the southern Berkshires as deepening low pressure pushes ENE early this morning. Have updated to bring conditions current, including headlines to be in line with the conditions especially across S RI/S coastal Mass. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM MONDAY/... The storm tonight will quickly depart within the progressive mid level flow. High pressure will build into the Mid Atlantic states, bringing drier and warmer conditions to southern New England during this period. Expecting a decent amount of snow melt Sunday afternoon. Good radiational cooling conditions Sunday night could lead to the formation of black ice on untreated surfaces. && .LONG TERM /MONDAY THROUGH SATURDAY/...
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Highlights... * Warm front likely brings a round of rain shower 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 decameter 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/...
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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 Tonight/... Overnight...Moderate confidence. Conditions deteriorating with onset -SN/SN, possible +SN for BDL to BOS and interior terminals S/E away from the coast. Some mixed -RA/-SN along S coastal terminals, with mainly RA at KACK. Lowering LIFR-VLIFR with 1/4SM SN VV002 for some toward midnight, but some question where the band of heavier snow will set up. IFR-LIFR for S coastal terminals with mix with, possible changeover to rain. Light/variable winds through 07Z-08Z become N-NW toward daybreak. Today... Brief leftover MVFR-IFR CIGS through 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...Moderate confidence. IFR conditions in -SN, may see conditions briefly lower to LIFR in occasional periods of SN through 08Z-09Z. Snow accumulations along runways of around 2-3 inches. Conditions improve to VFR by around 12Z-14Z. KBDL Terminal... Snow begin reported, will increase in intensity going towards midnight, diminishing a couple of hours after, light into the early morning hours. Looking for snowfall accumulations on the runways potentially up around 6 inches. Airport weather warnings may be needed for snowfall rates of 1-2 inches per hour. 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.
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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 Tonight/... Poor visibility with gusty E-SE winds expected tonight in snow and rain. Gusts could approach 30 kt. Rough seas expected to build once more across the outer coastal waters Sunday. Gusty NW winds develop in the wake of a departing low pressure, too. Small Craft Advisories posted for all the waters at some point tonight into Sunday. 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.
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&& .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...Frank NEAR TERM...Sipprell/EVT SHORT TERM...Belk LONG TERM...Frank AVIATION...EVT/Frank MARINE...EVT/Frank CLIMATE...Staff

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