Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 200832 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 432 AM EDT WED JUL 20 2016 .SYNOPSIS... High pressure in control will bring dry and warm afternoons through Thursday with comfortable humidity. The heat and humidity will return Friday along with the risk for scattered showers and thunderstorms during the afternoon and evening. Hot weather is expected to continue this weekend and an approaching cold front may bring us another round of scattered showers and thunderstorms sometime next Monday and/or Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... High pres continues to slowly slip S of the region this morning and through the day today. This should maintain the current SKC conditions throughout. This will allow for another day with a well mixed BL, leading to dwpts once again in the 40s and low 50s. H85 temps hover near +10C, so highs reach in the mid 80s. Overall a very pleasant Wednesday. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Tonight... Similar conditions. SKC with weak pres gradient, leads to radiational cooling. Only caveat will be a slight increase in overnight mins due to a combination of moderated airmass and gradual increase in moisture with high pres center just E of the region. Lows mainly in the low 50s to low 60s. Thu... High pres continues a slip to the SE. Return flow developing will lead to an increase in both low-level moisture and H85 temperatures to near +12C. Therefore, with sunshine outside of diurnal CU, expect highs reaching the upper 80s to near 90 away from sea breezes. Dwpts increase to mid-upper 50s and low 60s, still not too bad for July. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Highlights.. * Heat and humidity returns Fri, with some severe weather potential * Hot weather this weekend with highs mainly in the 90s * Another round of sct showers/thunderstorms possible sometime next Monday into Tuesday Details... Thursday night... Low level moisture continues to increase ahead of an approaching cold front. Mainly dry conditions expected to continue through much of the night. Small risk for showers across far western MA late. Patchy fog may develop late in the typically prone locations. Friday... We still have concerns about severe weather potential Friday into Friday night. The timing is not set, but currently favoring a typical diurnal pattern. While much of the day will be dry, it will become hot and humid. Model soundings continue to suggest the presence of an elevated mixed layer. Still need to see if this layer will develop, and arrive into our region in time to make a significant impact. It appears there should be plenty of forcing mechanisms and instability to support at least scattered thunderstorms. The strength of these thunderstorms is still in question. Saturday and Sunday... Consistent signal for another period of high heat and humidity. Winds appear to be strong enough to prevent an east coast seabreeze. The majority of this weekend looks dry right now, with a cold frontal passage early Saturday. Will need to determine how far south this front can get offshore before stalling. Monday and Tuesday... Very warm to hot temperatures likely continue with increasing humidity ahead of an approaching cold front. Depending on how far south the cold front make it and timing, there will be the risk for a round or two of scattered showers/thunderstorms during this time, but a washout is not expected. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Thursday/...High Confidence. VFR. Some light, late starting sea breezes today. Otherwise, W-NW winds. KBOS TAF...High confidence in TAF. KBDL TAF...High confidence in TAF. Outlook /Thursday Night through Sunday/... Friday...Moderate confidence. Mainly VFR. Scattered showers and thunderstorms may result in brief lower CIGS/VSBYS Friday afternoon and evening. Southwest wind gusts of 25 to 30 knots develop Friday afternoon along and southeast of a Boston to Providence line. Saturday and Sunday...High confidence in mainly VFR conditions. && .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Thursday/...High confidence. Mainly quiet boating weather through Wednesday Night thanks to high pressure building across the region from the W. NW winds veering out of the S/SW with time. Sea-breezes anticipated along the near-shore. Outlook /Thursday Night through Sunday/... Thursday...High confidence. Winds/seas mainly below small craft advisory thresholds most of the day. However, near shore southwest wind gusts of 20 to 25 knots and choppy seas are expected to develop along the south coast during the afternoon. Friday...Moderate confidence. Increasing southwest flow ahead of a cold front. This should allow wind gusts of 25 to 30 knots to develop Friday afternoon. Long southwest fetch will allow seas to build to between 4 and 7 feet, with the highest seas across the southern coastal waters. Saturday and Sunday...High confidence. Leftover swell will likely result in rough seas across the southern waters into the first part of Saturday. Otherwise, relatively weak pressure gradient should keep winds and seas below small craft advisory thresholds. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Belk/Doody NEAR TERM...Doody SHORT TERM...Doody LONG TERM...Belk AVIATION...Belk/Doody MARINE...Belk/Doody is the U.S. government's official web portal to all federal, state and local government web resources and services.