Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 161523 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 1023 AM EST Thu Feb 16 2017 .SYNOPSIS... Rapidly deepening area of low pressure lifts northeast across the southeast Canadian maritimes behind which snow lingers as winds out of the northwest remain blustery. Dry weather arrives Friday into Monday. A significant moderation in temperatures expected Sunday, when much of the region may see highs around 50 degrees. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Went ahead and dropped the advisory earlier in the morning as snow showers were weakening and clouds were breaking up. A few snow showers linger across Essex and Barnstable county but the main forcing for the advisory has been diminished. For today, potent shortwave will move across the region from north to south. CAA will begin to take hold over the region in gusty NW flow. As the wave moves through and temps aloft cool, surface temperatures will actually warm a few degrees. This temperatures difference will create steep lapse rates across southern New England. Appears that there is enough moisture within the low levels to create either rain and/or snow showers through the rest of the morning and into the early afternoon. Low confidence on where the highest coverage will be but for now will lean towards the coastal region as well as the higher terrain. These steep lapse rates will also make for gusty NW winds especially during the late morning into the afternoon. 925mb jet increases to about 30-35 kts which could result in gusts between 25-35 mph. These types of wind gusts combined with temperatures in the mid 30s will make it feel a lot cooler for much of the day.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
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Tonight... Any lingering snow shower will come to an by this evening as diurnal heating is lost and lapse rates weaken a bit. Still anticipate winds gusts to be up through the night especially across the coastal regions. Surface temperatures will drop into the teens away from the immediate coastline. Clearing skies may make a few interior locations drop below guidance but if wind gusts remain up then radiational cooling will be limited.
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&& .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Highlights... * Generally dry conditions through most of this period * Blustery and cold Friday * Moderating temperatures Saturday, and unseasonably mild Sunday * Above normal temperatures continue into early next week Details... Friday and Saturday... High pressure centered to our south becomes more slightly dominant in our neck of the woods. With this high pressure not directly overhead, expecting west winds to continue Friday, then shift southwest during Saturday. Dry weather should prevail, but we`ll have some clouds at times, moreso on Saturday as the warm air advection get underway and a weak shortwave arrives. Below normal temperatures Friday gradually rise to near normal levels for Friday night into Saturday. Saturday night and Sunday... Core of the deep closed low moves from the Maritimes toward southern Greenland. Meanwhile, a potent shortwave from the mid Mississippi Valley moves offshore through the Mid Atlantic states. The combined movement of these two features alters the mid level flow in our region to be more zonal for a time. This in turn will direct a low pressure to move from James Bay through the Saint Lawrence River valley. This will mean higher temperatures for southern New England, as we would be on the warm side of this low pressure. Some locations may approach 50 degrees Sunday, most likely across the lower terrain of eastern MA, RI and the lower CT River valley. Dry weather continues. Monday... High pressure expected to be in place across New England. This should mean near normal temperatures and mainly dry weather. Tuesday through Wednesday... This is the period of greatest uncertainty for this forecast, which is not atypical for this time range. The forecast for our region will depend on the extent of amplification of a downstream mid level trough over the Maritimes. 16/00Z ECMWF was quite aggressive in bringing its closed low well south of the other guidance, almost 10 degrees of latitude. After looking at the ensembles, am going to discount the ECMWF deterministic solution. Some hints there might be a warm frontal passage Tuesday, which could give us a slight chance for showers. Not a lot of humidity feature, so just have increasing clouds Tuesday, for now. Another high pressure to our south should then nudge a ridge into southern New England for Wednesday. Near normal temperatures expected. && .AVIATION /15Z THURSDAY THROUGH MONDAY/...
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Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Range /through Thursday/... Today...Moderate confidence. Any VFR terminals will drop back to MVFR as diurnal heating will increase cloud coverage today. Also cannot rule out a few snow showers today at any terminal site. NW winds, sustained around 10 to 15 kts, gusts 20 to 30 kts, strongest winds over the high terrain and along the coast. Tonight... MVFR to low-end VFR BKN cigs linger, gradually dissipating through the evening period. However blustery NW winds continue with sustained flow around 10 kts and gusts around 25 kts. KBOS TAF...Messy morning push. Improving conditions during the late morning hours into the afternoon with blustery NW winds throughout, especially after SN comes to an end, gusts up to 30 kts possible. KBDL TAF...Not much impact with respect to precipitation. Terminal should remain dry. Winds remaining blustery out of the NW. Outlook /Friday through Monday/... Friday and Saturday...High confidence. Mainly VFR conditions. Saturday night through Sunday night...Moderate confidence. May see patchy MVFR-IFR CIGS/VSBYS develop Saturday night across the CT River valley and east slopes of the Berkshires ahead of warm front. MVFR-IFR CIGS may linger Sunday and early Sunday night along the east slopes of the Berkshires. Elsewhere, mainly VFR. Monday...High confidence. Mainly VFR conditions.
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&& .MARINE...
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Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Range /through tonight/...Moderate Confidence. Blustery NW winds to gale force across the outer waters. Winds have dropped below 30kts so SCA has been issued for the rest of the waters. Outlook /Friday through Monday/... Friday and Friday night...High confidence. W-NW winds will continue to gust up to 25-30 kt, so Small Craft Advisories will likely continue for many of the waters. Light freezing spray will may persist into Friday morning, but should become less of a risk as winds diminish. Rough seas early, then will slowly subside but remain at or above 5 ft through Fri night across the outer coastal waters. Saturday through Sunday...High confidence. W-SW winds gusting up to 20 kt. Seas below 5 ft. Monday...Moderate confidence. NW winds may approach Small Craft Advisory levels across the eastern outer coastal waters.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ230>237-251. Gale Warning until 7 PM EST this evening for ANZ250-254>256.
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&& $$ SYNOPSIS...Belk/Sipprell NEAR TERM...Dunten SHORT TERM...Sipprell LONG TERM...Belk AVIATION...Belk/Sipprell/Dunten MARINE...Belk/Sipprell/Dunten

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