Area Forecast Discussion
Issued by NWS Boston, MA

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144 FXUS61 KBOX 301920 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 320 PM EDT MON MAY 30 2016 .SYNOPSIS... A cold front over New York will swing across Southern New England tonight. Scattered thunderstorms over Eastern New York will affect Western MA and CT before weakening. Another batch of showers moving up the front may graze the South Coast overnight. High pressure then builds over New England with dry weather for the middle of the week. Another cold front may bring unsettled weather by the end of next week. && .NEAR TERM /THROUGH TONIGHT/... Through 8 pm... There was sufficient heating over NY and PA to generate a few thunderstorms during the afternoon. These showers/storms are moving east into favorable instability over Eastern NY and the Berkshire/Litchfield Hills. The favorable instability then diminishes farther east. This means a chance for showers and a few tstms to cross into Western MA and NW CT around 530-600 pm. Movement father east will be increasingly difficult. Note that the 13Z HRRR was showing showers into the CT Valley around 6 pm and weakening over the Worcester Hills 7-8 pm. Tonight... Lingering convection should fall apart with the loss of daytime heating. The cold front will slowly cross New England during the night. Model data suggests the front may be able to pull some of the showers off the South Coast back to the north. This would mean another period of showers in this area overnight with light amounts expected. Dew points will be in the upper 50s and lower 60s overnight. This suggests min temps in the low to mid 60s. With temps and dew points nearly equal and winds light, expect more patches of fog overnight especially in areas that received a soaking during the day. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... There may be some lingering showers along the South Coast early Tuesday. But with high pressure building in, the trend will be for showers tapering off and sky cover diminishing. Drier air will work into New England with dew points falling through the 50s. A weak cold front dips south over the region late Tuesday. The main effect of this front will be to turn winds out of the north Tuesday night. This may bring dew points a little lower, roughly upper 40s to mid 50s. Sunshine Tuesday will create mixing to at least 850 mb, possibly higher. Temps at the top of the mixed layer will support max surface temps in the low to mid 80s. The lower dew points will allow min temps to be a little lower than tonight, generally in the 50s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Highlights... * Mainly dry with above normal temperatures Tue/Wed * Unsettled weather may return toward next weekend Medium range models are in good agreement on the overall synoptic pattern. A mid-level ridge will move offshore Wednesday. Mid- level troughing then moves into Quebec towards the end of the work week and starts influencing our weather with several shortwaves working around the base of the trough. This will result in more unsettled weather towards the end of the week. Wednesday...A back door cold front arrives on Wednesday. Temperatures will be above normal, especially across the western zones. Onshore flow will result in more seasonable temperatures along the east coast. Thursday through Sunday...Mid-level trough moves into Quebec allowing several shortwaves rotating through the base of the trough to move through southern New England. This will result in periods of showers, particularly Friday and Saturday. Due to the difficulty in pinpointing when and where these showers will occur, have kept chance PoPs in the forecast for much of this period. However, not expecting rain to be widespread, nor for the entire period. Temperatures will be around normal for much of the time. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tuesday Night/... Through 00z... Showers and a few tstms may cross into Western MA and CT around 21Z. These would bring potential MVFR cigs/vsbys during the evening before dissipating. Tonight...Moderate confidence. Lingering IFR cigs and vsbys in fog and showers along the south coast. Mixed VFR/MVFR farther north. Local IFR/LIFR is possible in these areas overnight due to patchy dense ground fog. Tuesday and Tuesday night...High confidence. VFR. KBOS TAF...Moderate confidence in TAF. KBDL TAF...Moderate confidence in TAF. Outlook /Wednesday through Saturday/... Wednesday...Moderate confidence. VFR. Thursday...Moderate confidence. Mainly VFR conditions expected. Increasing clouds with diminishing conditions through the night, particularly along the south coast. Friday...Moderate confidence. Mainly VFR conditions expected. Brief MVFR conditions are possible in SCT -SHRA at times. && .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tuesday Night/...High confidence. Tonight...Moderate confidence. Poor visibility due to dense fog. Best chance for this will be across the southern waters from Block Island to Nantucket. Winds will remain below 20 knots. Seas will remain below 5 feet. Tuesday and Tuesday night...Moderate confidence. A south swell builds into the southern waters Tuesday. Expect the swell to reach 4 feet during the day, with potential for 4-5 foot swell Tuesday night. Southwest wind Tuesday shifts from the North Tuesday night, but remains below 20 knots. Outlook /Wednesday through Saturday/... Wednesday...Moderate confidence. Northeasterly winds and seas will remain below Small Craft Advisory criteria. Thursday...Moderate confidence. Easterly winds and seas increase. Seas may rise above 5 feet, especially on the outer waters. Friday...Moderate confidence. Easterly winds are expected to remain below 15 kts. Seas decrease through the period. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...WTB/RLG NEAR TERM...WTB SHORT TERM...WTB LONG TERM...RLG AVIATION...WTB/RLG MARINE...WTB/RLG

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