FXUS61 KBOX 260725 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 325 AM EDT Fri Apr 26 2024 .SYNOPSIS... High pressure across the northeastern states allows for dry weather, chilly nights, and comfortable afternoons through the first-half of the weekend. Unsettled pattern sets up for Sunday into early next week with shower chances. Temperatures turn milder for some but a back door cold front likely keeps the warmest air over western SNE Monday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Highlights: * Freeze Warning: In effect until 8 AM for northern CT, RI, and southeast MA. No changes made to the Freeze Warning, temperatures continue to settle into the middle and lower 30s, with the coldest spots on the Cape and Vineyard, here temperatures tumbled into the 20s. One area that has been tough to nail down is the CT River Valley, this area has stayed a bit warmer than guidance. Likely due to the dewpoints remaining elevated for much of the first-half of the night. Do think temperatures will drop another 2 to 4 degrees before sunrise, which would have many locations in the upper 20s to low 30s around the time of sunrise. Otherwise, a quiet and sunny day ahead with surface high pressure firmly in place over southern New England. Nearly a carbon copy forecast from Thursday. After starting with temperatures in the 20s and low 30s, today warms into the upper 50s and low 60s for most, though coastal towns remain cooler. Why? An on shore wind/ sea breeze develops by mid-morning. Here temperatures reach the low 50s. With a sprawling high pressure system the mean wind direction of the boundary layer is tough to nail down, do think wind direction is a bit variable today, though eastern Massachusetts sees an easterly wind due to the sea breeze. Southern Rhode Island and south coast of Massachusetts seas more of a southerly wind, once again due to the sea breeze. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... Copy & Paste: Yet another dry, clear, and cold night across southern New England. That said, do not think temperatures dip as low as it has done the past two nights. Given repetitiveness of the forecast, leaned on the biased-correct CONSMOS and made manual adjustments to our prone locations that radiate on clear and calm nights. Overall, widespread lows in the middle and upper 30s for the coastal plain and upper 20s and low 30s across the interior. Where we could see temperatures drop lower, our known radiators; I-495 corridor, hallows of eastern CT, and Martha's Vineyard - Here temperatures may drop between 28F and 32F. Given the limited area, will hold off this morning on issuing a Freeze Watch. This situation might be better handled with a Frost Advisory, but will leave that up to the day crew after reviewing the latest data. As for Saturday, a sunny and comfortable one with surface high pressure anchored south of Block Island. Light winds and clear skies will allow for temperatures to climb into the low and middle 60s away from the coast. At the coast, a sea breeze likely to develop given persistent pattern, highs will only reach the middle and upper 50s. By late afternoon a mid-level shortwave approaches from the west with a surface warm front. Day light hours remain dry, though mid and high clouds begin to move in from west to east during the late afternoon. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Key Points... * Scattered showers Saturday night become more hit-and-miss Sunday into Monday; more widespread rain chances through mid week with potential for a thunderstorm. * Warming trend through next week but a back door cold front likely keeps warmest air confined to western SNE. Details... Sunday and Monday... A passing warm front and weak isentropic lift will lead to widely scattered showers across southern New England Saturday night. Lack of strong forcing will limit rainfall amounts to a few hundredths to a few tenths focused over western MA/CT with lesser amounts to the east. This comes as high pressure sinks south of the region and the trough of low pressure drops from Canada into New England Sunday into Monday. Thus, despite being on the periphery of a mid level ridge can't rule out some hit-and-miss showers each day with a good amount of cloudcover. The biggest impact of the track of this low will be a backdoor cold front that, despite a steadily warming mid level airmass (850 mb temps up to +10C by Monday for some), will keep the more significant warm up confined to western MA/CT on Monday. There remains a high degree of uncertainty with respect to high temperatures, especially Monday as the front looks to drop through Sunday night. Tuesday through Thursday... Guidance is looking slower to kick steering flow back to southerly for Tuesday which is not increasing confidence in the temperature forecast beyond Monday either. A seasonable airmass does look to remain in place though, with highs in the low to mid 60s for Tuesday and warming further Wed/Thu. Again, this will be highly dependent on the how the pattern evolves beyond Monday which remains uncertain. What is largely agreed upon is our mid level ridging finally breaking down with a shortwave and frontal system moving through on Tuesday bringing the return of more widespread rain showers. Some thunderstorms are possible, mainly over western MA/CT where there exists several hundred J/kg of CAPE but forcing does not look especially strong. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 08z TAF Update: Through 12z... High confidence. VFR. Light and variable winds. Today... High confidence. VFR. Light winds and at times variable direction less than 6 knots, though coastal terminals will have an onshore wind around 10 to 12 knots, sea breeze develops between 15z-17z. Tonight... High confidence. VFR. Light and variable winds. Chance of patchy fog in areas that radiate. Saturday... High confidence. VFR. Increasing high clouds by late afternoon. South/southwest winds 10 to 15 knots. KBOS TAF...High confidence. VFR. Sea breeze develops again by 14-15z. KBDL TAF...High confidence. VFR. Light and variable winds. Outlook /Saturday Night through Tuesday/... Saturday Night: Mainly VFR, with local IFR possible. Chance SHRA. Sunday: Mainly VFR, with local IFR possible. Slight chance SHRA. Sunday Night through Monday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Tuesday: Mainly VFR, with areas MVFR possible. Slight chance RA. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today through Saturday... High confidence. Tranquil boating conditions through Saturday as high pressure builds southeastward into the coastal waters. Today: Sunny. Light north winds (easterly near shore) early today, this afternoon, winds turn southerly around 10-15 kt. Seas 3 ft or less. Tonight: Dry. Winds becomes more westerly and are less than 10 knots. Seas 2 ft or less. Saturday: Sunny. Increasing southwest winds 10 to 15 knots, seas 2-3 ft. Outlook /Saturday Night through Tuesday/... Saturday Night through Sunday Night: Winds less than 25 kt. Slight chance of rain showers. Monday: Winds less than 25 kt. Monday Night: Winds less than 25 kt. Slight chance of rain showers. Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Freeze Warning until 8 AM EDT this morning for CTZ002>004. MA...Freeze Warning until 8 AM EDT this morning for MAZ007-014>024. RI...Freeze Warning until 8 AM EDT this morning for RIZ001>007. MARINE...None. && $$ SYNOPSIS...BW/Dooley NEAR TERM...Dooley SHORT TERM...Dooley LONG TERM...BW AVIATION...BW/Dooley MARINE...BW/Dooley