Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 252334 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 634 PM EST Sat Feb 25 2017 .SYNOPSIS... A strong cold front will cross the region tonight, bringing showers and a low chance for thunderstorms as this front passes. Blustery conditions with more seasonable temperatures expected for Sunday. Well above normal temperatures return Monday, and likely remain through much of next week. A couple of weather systems will bring periods of wet weather Tuesday into Thursday. Colder air looks to return late next week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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Will continue to monitor thunderstorm risk across the western half of southern New England this evening. Latest mesoanalysis continues to show an unfavorable airmass across much of southern New England. While the instability is low, the effective shear associated with the convective line was about 60 kt. This may be enough to sustain some stronger storms for a couple more hours across western MA and northern CT. At this time, not expecting any strong thunderstorms east of central MA and RI. Previous Discussion... Fine line of convection along the cold front moving into eastern NY. Sct to numerous t-storms along this line where MUCAPES 250-500 J/kg but MUCAPES 1000-1500 J/kg further south across SE PA where greater severe wx threat exists. Hi-res guidance indicates this line will move into western MA and northern CT 00-02z. Strong mid level omega holds together into W MA along with 40-50 kt LLJ so expect the line to maintain itself as it moves into W MA early this evening but the line of convection will begin to outrun better instability to the west so some weakening is expected. Still expect brief heavy downpours and gusty winds in western MA and N CT with low risk of an isold damaging wind gust if convection can mix down stronger winds aloft. Will have to monitor radar closely as deep layer shear and 0-1km helicity values are quite robust and damaging wind or even a brief tornado is favorable in this environment if instability is greater than forecast. As the line moves east across central and eastern New Eng 02-06z it will diminish and weaken as mid level omega weakens rapidly and becomes fragmented. So just a few showers expected by the time it gets to eastern MA. The rain may end as a brief period of snow showers in the Berkshires as deeper colder air rushes in behind the front, but moisture will be exiting as the cold air moves in. Low risk of a coating to less than an inch in the Berkshires. Gusty W/NW winds develop behind the cold front which moves through SNE 01-06z from west to east. Gusts to 30-40 mph possible, strongest over higher terrain. Min temps by Sun morning will range from 35 to 40 degrees, except upper 20s to lower 30s over the higher terrain in central and western MA
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&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... Sunday...Mid level shortwave moves east of New Eng. Expect partly to mosunny skies with sct-bkn strato-cu developing in cold advection pattern. Gusty W/NW winds expected with soundings supporting gusts to 35 mph with chance of a few gusts over 40 mph across the higher terrain where low prob a wind advisory may be needed. Much colder airmass Sun as 850 mb temps drop to -8 to -10C. However, temps will likely overachieve a bit as soundings indicate mixing above 850 mb with good downsloping. Expect maxes ranging from the upper 30s higher elevations to the mid 40s in the coastal plain with a few upper 40s possible. Sunday night... Surface high moves off mid Atlc coast with ridge axis moving east of New Eng. Winds will diminish and shift to SW overnight. Column is dry except for some increase in mid/high level moisture. Expect mostly clear to partly cloudy skies with mins ranging through the 20s. && .LONG TERM /MONDAY THROUGH SATURDAY/... Highlights... * Above average temperatures for next week * Widespread showers possible Wednesday/Thursday * More seasonable conditions return Friday Overview... 25/12Z guidance remains in rather good agreement through this period. Mainly a nearly zonal flow aloft near New England, while a deeper mid level trough develops over the western USA. This would favor above normal temperatures, as well as a storm track to our north and west. Eventually, this mid level trough will move east, reacquainting our region to winter. Favored a consensus approach to smooth over the less predictable details. Timing the arrival of the aforementioned trough is not yet set in stone, and could change with later forecasts. Details... Monday...High confidence. High pressure remains to our south, maintaining a southwest flow for our region with dry weather. Expecting another good mixing day, with strong west winds of 40-50 kt at 925 mb. Gusty winds should be the result. Eventually, this high pressure moves off to the east. This should permit a shortwave passing just south of our region to bring a chance of showers Monday night towards the south coast. It`s possible this wave passes even farther south, which would keep mean drier weather Monday night. Tuesday...High confidence. High pressure continues to move east, as a second, more potent, shortwave arrives later in the day. Southwest flow aloft will help saturate the profile. Depending on when this occurs, we could see a few flakes north of the Pike early in the day. However, confidence remains low on any snow occurring. Will continue the forecast of clouds and showers. Wednesday into Thursday...Moderate confidence. Main weather producer for this portion of the forecast still anticipated to impact our region sometime between early Wednesday morning and Thursday afternoon. The low pressure should stay well to our north and west, so we`re looking at a more wet than white forecast. South to southwest winds will maintain temperatures well above average for late February. Moisture content with this system is above normal for this time of year. However, this system is progressive, so still not expecting a large amount of rain. Very strong low level jet may impact our region, if it comes farther north. Any heavy rainfall could produce strong gusts. Some weak instability, so thunderstorms are possible. Still a lot of details to work out, but a system to watch in the coming days. Friday and beyond...Moderate confidence. As the cold front with the mid week low pressure passes through our region, west to northwest winds take a hold across our region. Mainly dry weather with a return to more wintry temperatures. Can see a scenario where ocean-effect clouds and snow could develop, if temperatures get low enough. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/...
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Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Sunday Night/... Tonight...Moderate confidence. Widespread showers and isolated thunderstorms will move through western New England 00-02Z, then diminish in both intensity and coverage as it moves into eastern New Eng 03-06Z. Brief heavy rain and gusty winds possible with any thunderstorms in western New England. Precipitation may end as brief period of snow showers near the Berkshires 03-06Z. IFR/MVFR cigs with patchy fog will improve to VFR after cold fropa and wind shift to W/NW 02-06Z. W/NW gusts to 30 kt developing after the wind shift, with G35 kt possible over higher terrain. Sunday...High confidence. VFR with sct-bkn cigs 4-5k ft. W/NW gusts to 30 kt, higher gusts possible over higher terrain in the morning. Sunday night...High confidence. VFR. Diminishing W wind becoming SW overnight. KBOS TAF...Moderate confidence through this evening, then high confidence in improving conditions overnight. KBDL TAF...Moderate confidence through this evening, then high confidence in improving conditions late this evening. Outlook /Monday through Thursday/... Monday...High confidence. VFR with westerly wind gusts near 20-30 kt. Tuesday...Moderate confidence. Generally VFR, with MVFR conditions possible south of the Pike in showers. Wednesday into Thursday...Moderate confidence. MVFR to possible IFR in -SHRA/-RA.
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&& .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Sunday Night/...High confidence. Tonight...Moderate confidence. Southerly winds shift to W/NW behind a cold front 03-06z. Increasing post-frontal winds with a few marginal gale force gusts to 35 kt expected. Will continue gales for most of the open waters. Sunday...High confidence. W/NW gusts to 30-35 kt, especially during the morning with a gradual diminishing trend during the afternoon. Sunday night...High confidence. Diminishing W winds in the evening becoming SW overnight. Another surge of 25-30 kt gusts expected toward daybreak. Outlook /Monday through Thursday/... Monday...High confidence. Improving conditions with gusts near 20 kts and seas beginning to subside as high pressure builds over the southern waters. Tuesday...High confidence. Relatively quiet boating weather during the day. Seas build late Tuesday night Wednesday into Thursday...Moderate confidence. More widespread rainfall with lower vsbys possible. Increasing south to southwest winds with building seas. Small Craft Advisories likely, with a low risk for gale force gusts. && .HYDROLOGY... We will need to monitor rising water levels across southern New England into early next week. Much, if not all, of our snowpack has, or will have, melted. There is still much more snowpack upstream, over northern new England, that will push into the headwaters and head downstream. Some river levels could approach action stage. && .CLIMATE... RECORD HIGH TEMPS FOR YESTERDAY BOS 73/2017 - previous record 70/1985 PVD 72/1985 - topped off at 71 degrees (no record) BDL 73/1985 - topped off at 72 degrees (no record) ORH 69/2017 - previous record 67/1985 RECORD HIGH MIN TEMPS FOR YESTERDAY BOS 49/1930 - bottomed out at 46 (no record) PVD 45/2017 - ties previous record of 45/1984 BDL 43/1981 - bottomed out at 42 (no record) ORH 48/2017 - previous record 46/1985 RECORD HIGH TEMPS FOR TODAY BOS 65/1930 * broken 69 degrees PVD 69/1976 BDL 70/1976 * tied 70 degrees ORH 64/1976 * broken 65 degrees RECORD HIGH MIN TEMPS FOR TODAY BOS 46/1891 PVD 45/1930 BDL 45/1930 ORH 37/1996, 1984, 1976 DEW POINTS OF NOTE FOR YESTERDAY BOS Max Dew Point 54 ties highest for date set in 1985 PVD Max Dew Point 53 is highest for date. Previous high 50/1990 BDL Max Dew Point 54 is highest for date. Previous high 49/1990 ORH Max Dew Point 53 is highest for date. Previous high 48/1985 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Gale Warning from 2 AM to 11 AM EST Sunday for ANZ231>235-251. Small Craft Advisory from 11 PM this evening to 7 PM EST Sunday for ANZ230-236. Small Craft Advisory from 11 PM this evening to 10 PM EST Sunday for ANZ237. Gale Warning from 2 AM to 2 PM EST Sunday for ANZ250-254>256. && $$ SYNOPSIS...Belk/KJC NEAR TERM...Belk/KJC SHORT TERM...KJC LONG TERM...Belk AVIATION...Belk/KJC MARINE...Belk/KJC HYDROLOGY... CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.