Area Forecast Discussion
Issued by NWS Boston, MA

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781 FXUS61 KBOX 240806 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 406 AM EDT Sat Sep 24 2016 .SYNOPSIS... Cool and dry weather this weekend will continue into early next week. A slow- moving low pressure and cold front could lead to some showers late next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Cold front just on the verge of the S coast as of 3AM and continuing to both wash out and move offshore. The loss of the F-gen associated with the front, combined with the drier air spilling in from the N has led to a near end of the SHRA across the region. ONly a few more left after 8Z. Otherwise, continued dry air entrainment and mixing in the next few hours should allow dwpts to drop into the 40s and head for the 30s by evening. Full clearing may require a few more hours as there is some trapped low clouds as far N as the Monadnocks which have yet to dissipate. However, trend toward clear expected. H92 temps will be dropping through the day, but not as quickly as overnight tonight. Therefore, looking at highs still able to reach the low 70s thanks to slight W component to the flow in typically warmer spots (Merrimack and CT River valleys). Elsewhere, mid to upper 60s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Tonight... With fall-like airmass settling in, clear skies and a weakening pres gradient, looking at a good night for radiational cooling. One of the cooler nights in recent memory expected. Bufkit inversions suggest temps in sheltered valleys could reach mid- upper 30s, particularly in NW MA. As such, will hoist Frost Advisory for Franklin CO. This could potentially be expanded. Elsewhere, still expect upper 30s to mid 40s. Tomorrow... With a cool start, in spite of what should be abundant sunshine, high temps will only be able to reach low-mid 60s. Light NW breezes definitely will give it a fall feel. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... HIGHLIGHTS... * Areas of Frost possible Sunday Night across NW zones * Frontal system late Monday/Tuesday will bring widespread showers * More seasonable temperatures return by Tuesday Overview/confidence... High confidence in below average temperatures Sunday night into Monday. Model guidance is in better agreement then 24 hours ago with passing frontal system bringing precipitation to the region late Monday into Tuesday. Temperatures will turn more seasonable for the remainder of the week. Guidance does begin to spread by late Wed into Thursday. The EC builds the North Atlantic ridge stalling the upper level low over the Ohio Valley where at the GFS is a bit less amplified keeping the cut-off low over New England. This leads to difference in both temperature and precip chances. Continues with model blend until guidance becomes more inline. Sunday night into Monday...High Confidence. High pressure settles over the region Sunday night resulting in light winds and clear skies. This will allow for radiational cooling which could plummet temps into the low to mid 30s away from the urban centers and coastal regions. Frost advisories will have to be issued with the potential for a possible freeze warning for NW zones. Will hold off for now due to current frost advisory to avoid double headlines. High pressure will remain over the region for most of the day before sliding offshore by the evening. Sea breeze development is possible across both coastlines. Otherwise anticipate a mostly sunny skies for most of the day with temperatures warming into the mid to upper 60s. Monday night into Tuesday...Moderate Confidence. Upper level ridge will move overhead Monday night as WAA spills into the region. Overnight temps will begin to fall during the evening hours before remaining steady or even rising by the early morning hours. A few showers are possible during the overnight hours, but the bulk of the rain will move through on Tuesday. Ahead of the FROPA, temperatures will warm into low 70s across the area. Dewpoints will be on the rise as well making it feel a bit more humid. Appears the best timing will be Tuesday morning which could make way to a rough morning commute. GEFS continue to show 70- 80 percent probs of over a half of an inch of rain, so confidence is increasing in widespread rainfall. Lastly, a good pressure gradient behind the passing frontal system could result in gusty winds near 20-25 mph. Wednesday and Beyond...Low Confidence. Guidance begins to diverge within this timeframe as mentioned above. EC keeps the region more wet by late next week with the upper level low to our west. The GFS is a more dry scenario with perhaps a few diurnal showers within the cold core low over the region. Will continue with a model blend for temperatures but will keep the forecast dry for now until guidance spread decreases. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through 12Z...Moderate confidence. Remnant MVFR conditions and -SHRA continue to dissipate and shift offshore. It should, it should clear most of CT/RI by 08Z, then SE MA by 10Z with gradual clearing from N-S. Even before full clearing, CIGS should lift to VFR. Today through Sunday...High confidence. Mainly VFR. Near shore wind gusts out of the N-NW 20-25 kt at times late today and tonight. KBOS TAF...High confidence in TAF. KBDL TAF...High confidence in TAF. Outlook /Sunday Night through Wednesday/... Monday...High confidence. VFR. Sea Breezes along the coast. Monday night thru Wednesday...Moderate confidence. VFR through the period with localized MVFR in rain on Tuesday. Gusty winds southerly winds near 30 kts across East coastal terminals. Improving trend on Wednesday. && .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today...High confidence. Although winds and seas will begin to subside through the day, seas on the ocean waters will hold right around 5 ft. Therefore, will continue small craft advisories. Tonight into tomorrow...High confidence. Resurgence of NW winds to near 25 kt will likely require near shore waters to once again have a small craft advisory, and continue the ocean waters. Seas will be the issue tomorrow, dropping from about 6-7 ft through the day. Outlook /Sunday Night through Wednesday/... High confidence in high pressure settling over the waters Sunday night into Monday. This will allow in lingering 5 foot seas to dissipate. Strong cold front will approach the waters late Tuesday. Ahead of the front southerly winds will increase just shy of gales with seas building as a response. Vsbys will drop within any heavy rain showers as the front passes. Winds and seas will relax by Wednesday as weak high pressure builds back over the waters. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Frost Advisory from 2 AM to 8 AM EDT Sunday for MAZ002-003. RI...None. MARINE...Small Craft Advisory until 8 AM EDT this morning for ANZ231>235-237-251. Small Craft Advisory until 5 PM EDT Sunday for ANZ250-254>256. && $$ SYNOPSIS...Doody/Dunten NEAR TERM...Doody SHORT TERM...Doody LONG TERM...Dunten AVIATION...Doody/Dunten MARINE...Doody/Dunten

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