Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 220603 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 203 AM EDT Sun Apr 22 2018 .SYNOPSIS... High pressure remains in control through Tuesday bringing dry weather with moderating temperatures. Wet weather returns Wednesday into Thursday as low pressure moves through our region. Mainly dry weather follows on Friday before becoming dreary again next weekend. && .NEAR TERM /THROUGH TODAY/... High pressure builds over the region today. Moisture cross sections show a moist layer between 750 mb and 850 mb this afternoon. This may be enough to generate a few clouds above 5000 feet, but otherwise a sunny day. The light pressure gradient will mean light winds today, but will also be favorable for sea breezes developing along the coast during the late morning/midday and continuing through afternoon. Mixing yesterday reached to nearly 750 mb, per 00Z soundings. Model cross sections show mixing to 800 mb today. Temperatures at that level will be -5C to -6C, which is equivalent to 0C to -1C at 850 mb. Fully mixed, this would favor max sfc temps in the upper 50s and around 60. Mixing a little deeper would support max temps 60-65. Cooler temperatures near the coast due to the sea breeze. && .SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/... High pressure remains overhead tonight and Monday. Expect radiational cooling tonight, bringing another chilly night with areas of frost, even some temps below freezing. Sunny skies on Monday with light wind, which will again allow developing sea breezes. Similar deep mixing to today, but with temperatures a few degrees warmer and supporting sfc max temps in the low to mid 60s away from the cooler coast. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... */ Highlights... - Warm up early next week - Wet and breezy midweek - Perhaps a reprieve Friday - More showers possible Saturday 21/12Z guidance remained in rather good agreement with the overall synoptic pattern through Wednesday. Then typical timing and amplitude differences creep into the solutions. Prefer a consensus blend to smooth over the less predictable features for this time range. Expecting well defined mid level northern and southern stream features to phase over the central Appalachians about mid week. Guidance remained consistent with that idea from previous runs. It`s how the pattern evolves after this phasing where some questions remain, particularly with timing. In most cases, looking like a period of wet weather sometime Wednesday, and perhaps lingering into Thursday. Depending on timing, another front may pass through our region sometime Friday into Saturday. Temperature-wise, looking much closer to normal early next week. Seabreezes likely on Monday, so cooler towards the coasts. Below normal temperatures should return mid week, then remain near to below normal into next weekend. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Monday/...High confidence. VFR through the period with light wind. Coastal seabreezes will develop midday/afternoon, dissipate in the evening, then redevelop Monday midday/afternoon. KBOS Terminal...High confidence in TAF. Moderate-high probability of a sea breeze midday/afternoon. KBDL Terminal...High confidence in TAF. Outlook /Monday Night through Thursday/...High confidence. Monday night through Tuesday: VFR. Tuesday Night: Mainly VFR, with local MVFR possible. Breezy. Chance RA. Wednesday: Mainly MVFR, with areas IFR possible. Breezy. RA likely. Wednesday Night: Mainly VFR, with areas IFR possible. Breezy. Chance RA. Thursday: Mainly VFR, with local MVFR possible. Chance RA, slight chance SHRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Monday/...High confidence. Light winds and seas. Winds turning onshore near the coast midday/afternoon and again Monday midday/afternoon as sea breezes develop. Outlook /Monday Night through Thursday/...High confidence. Monday night through Tuesday: Winds less than 25 kt. Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain. Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Rain likely. Wednesday Night: Winds less than 25 kt. Areas of rough seas. Chance of rain. Thursday: Winds less than 25 kt. Areas of rough seas. Chance of rain, slight chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...WTB/Belk NEAR TERM...WTB SHORT TERM...WTB LONG TERM...Belk AVIATION...WTB/Belk MARINE...WTB/Belk

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