Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 030850 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 350 AM EST Wed Mar 3 2021 .SYNOPSIS... Dry weather is expected through early next week. Temperatures moderate today, then drop below normal Thursday through the weekend. Above normal temperatures return by early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Warm front lifts north and east of the region this morning. Mid-level clouds will move off with the front, bringing sunshine for the day. Mixing is expected to reach to 900-mb, with temperatures at that level supporting surface max temps in the 40s, possibly around 50 in spots. Winds in the mixed layer will support westerly gusts around 15-20 kt/20 to 25 mph. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Tonight... Cold front sweeps south across Srn New England. There will be a shortwave aloft, but little jet forcing to cause lift. The airmass also looks fairly dry. Aside from a stray snow flurry, expect a dry frontal passage. Winds will shift out of the northwest after the front moves past, drawing colder air south over our area. Dew points will remain in the 20s, so expect overnight temps to be no colder than the 20s. Thursday... Northwest winds will continue to draw somewhat colder air in place. The air will be dry, so expect sunny skies. Temperatures aloft will cool by about 7C degrees within a similar mixed layer to today, so expect somewhat cooler temperatures compared with today. Temperatures aloft will support max sfc temps in the 30s, possibly lower 40s south of the Mass Pike. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Highlights... * Below normal temperatures with mostly dry conditions late week into the weekend. * It looks increasingly likely that we will make a run for the 50s by middle of next week. Thursday night into Sunday... Overall, expect a period of minimal impact weather across Southern New England as we remain in a northwest flow regime which will keep temperatures slightly below normal but also suppress storm systems to our south. Normal highs for early March are in the low to mid 40s. Expect daytime highs to generally run 5 to 10 degrees below normal. This is coincident with a brief period of +PNA and -AO, which favors upstream ridging over the Northern Rockies and a more persistent H5 trough east of the Mississippi River. The main driver for this cooler pattern is a meandering sub-500mb upper low over Newfoundland that will allow for a series of backdoor cold fronts to affect New England through this weekend and helping to keep temperatures below normal. Unfortunately for snow lovers, it also means that storm systems are suppressed well to our south. Given the overall synoptic pattern, our best chances of precipitation looks to be in the form of ocean-effect snow showers for the coastal areas and upslope snow showers for the interior high terrain. Another indicator of above average confidence in dry conditions is that the GFS/EC/GEM ensembles all show zero percent probability of total snow exceeding one inch through next Tuesday. By Sunday, the aforementioned closed low over Newfoundland finally moves further offshore, allowing for a H5 ridge to build into our area and finally commencing a warming trend. Models have come into better agreement that 40s will have to wait till Monday with highs this weekend looking to be in the 30s. The cool conditions looks to be offset by plentiful sunshine and mainly dry conditions. An ocean storm expected to pass well southeast of New England could also switch the winds to the north-northwest briefly, which would allow for ocean-effect snow showers over parts of Eastern MA and Cape Cod with 850mb temperatures between -12 to -15C and the SSTs around 40F. Monday into Tuesday... The new work week looks to feature a transition into a +AO/+NAO/-PNA regime, which is favorable for a more significant and prolonged warm up. This winter has been notable for the lack of anomalous warmth, unlike the previous winter. All four of our climate sites have gone a considerable amount of time without exceeding 50F for high temperature. Boston and Providence last saw above 50F on January 16 2021, with highs of 52 and 55F respectively. Hartford and Worcester last saw above 50F on Christmas Day last year, with highs of 63 and 61F respectively. This run is likely to come to an end by next Tuesday, if they don`t exceed 50F this afternoon. In fact, the CPC has a 70 percent probability of above normal temperatures for Southern New England in its latest 6 to 10 day outlook. Talk about a taste of spring! && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today through Thursday...High Confidence. VFR. West southwest winds gusting to 20 kt today diminish tonight, then turn from the northwest on Thursday. Northwest winds gust 20 to 25 kt Thursday. KBOS TAF...High confidence. VFR. KBDL TAF...High confidence. VFR. Outlook /Thursday Night through Sunday/... Thursday Night: VFR. Windy with local gusts up to 30 kt. Friday through Saturday Night: VFR. Breezy. Sunday: VFR. && .MARINE... Today through Thursday...High Confidence. Winds continue to diminish today, generally at Small Craft conditions this morning. Most waters will be lower than Small Crafts at some point this afternoon, with the southern outer waters not becoming lighter until early tonight. Winds shift from the northwest tonight as a cold front sweeps through. Northwest winds Thursday will increase to 25 kt with seas building to 5-6 feet on the outer waters toward evening. Outlook /Thursday Night through Sunday/... Thursday Night: Strong winds with gusts up to 30 kt. Areas of rough seas. Chance of freezing spray. Friday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Chance of freezing spray. Friday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of freezing spray. Saturday: Winds less than 25 kt. Seas up to 5 ft. Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Sunday: Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ232>235-237. Small Craft Advisory until 1 PM EST this afternoon for ANZ230- 231-236-251. Small Craft Advisory until 3 PM EST this afternoon for ANZ250. Small Craft Advisory until midnight EST tonight for ANZ254>256. && $$ SYNOPSIS...WTB/Chai NEAR TERM...WTB SHORT TERM...WTB LONG TERM...Chai AVIATION...WTB/Chai MARINE...WTB/Chai is the U.S. government's official web portal to all federal, state and local government web resources and services.