Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 191000 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 500 AM EST Fri Jan 19 2018 .SYNOPSIS...
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Dry and seasonably cold conditions today, then a warming trend this weekend with continued dry weather. A storm system will bring the potential for heavy rain and strong coastal winds late Monday night into Tuesday, but there is a risk of some wintry mix/ice across the interior late Monday and Monday night. Blustery, dry and seasonably cold weather will follow Wednesday and Thursday.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Low clouds continue to linger across Cape Cod as seen on latest GOES-16 Nighttime Microphysics Composite satellite imagery, along with some lower clouds across portions of the CT Valley into the Berkshires. Also seeing some mid and high clouds passing across the lower CT valley into central and E Mass at 09Z. Line of precip moving across eastern VT into NH, and continues to shift E on the latest NE regional 88D radar. May see a few spotty snow showers along the MA/NH border through around 12Z or so as the H5 short wave moves off the Maine coast and into the Gulf of Maine by mid morning. Will see some breaks in the clouds across most areas through around midday, then some more clouds will approach from the W during the afternoon, with more clouds across NW Mass and the E slopes of the Berkshires. Noting some decent low level mixing up to H925 with some gusts up to 20-25 kt from about midday onward. Also see a 35 kt H85 jet moving across the waters later this afternoon. Will likely see gusts up to 25-30 kt developing especially across the southern waters. Have posted Small Crafts there. Expect temps to top off in the 30s, mildest across areas S of the Mass Pike.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
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Tonight... Expect a general W wind flow in place as large high pressure moves off the mid Atlantic and Carolina coast. As winds become mainly zonal across the region, low level wind data indicating a 35-40 kt jet up to H9 which increases to 45-50 kt by around 12Z Sat. However, some question on the low level lapse rates and whether it will mix down. Noting very good low level lapse rates at H95 especially across the southern waters after 06Z Sat. Looks like will see a good gradient in place which will drive the W winds, which will become gusty along the immediate coast and especially across the waters after midnight. Better shot will be across the waters. Temps will fall to the mid 20s to around 30 early tonight, then will level off or even rise a bit after midnight on W-SW winds which will gust up to around 20-25 kt along the S coast, Cape Cod and the islands. Saturday... Still noting strong low level jet crossing the immediate coast and across the coastal waters during Sat, upwards to 45-50 kt which could mix down with the good low level gradient in place. Will see westerly wind gusts up to 20-25 kt across the higher inland terrain, and up to 25-35 kt along the S coast, Cape Cod and the islands. May need wind advisories for portions of the S coast. Another weak H5 short wave moves across northern New England. Not expecting any precip with it, but could see mid and high clouds cross central and northern Mass during the day. Good warm air advection sets up, with H85 temps up to +5C to +7C across central and southern areas Sat morning on W-SW winds, though cooler air may work southward during the afternoon as H85 temps fall. Have forecasted highs in the upper 40s to lower 50s across the lower CT valley to the coastal plain, but will be a bit cooler along the S coast with the gusty winds off the colder waters as well as over the higher inland terrain.
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&& .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... 230 AM update... Highlights... * Dry and mild Sunday * Risk of some wintry mix/ice in the interior late Mon/Mon night * A period of heavy rain and strong coastal winds likely late Mon night into Tue * Blustery and seasonably cold Wed/Thu Sunday... Less wind Sunday with NW flow but continued mild with temps in the 40s across much of the region. Expect mostly sunny skies as axis of mid/high level moisture across northern New Eng. Turning colder Sun night as cold front drops south across the region with strong high pres building across Canada and ridging nosing down into New Eng. Monday into Tuesday... Developing warm advection pattern ahead of warm front will lead to some light precip developing Mon afternoon and more likely Mon night. With high pres to the N/NE and good cold air damming signature, thermal profiles should be cold enough for some light snow/mix/ice in the interior with minor accum possible. A brief mix is also possible at the onset in the coastal plain. However, the main event will likely be late Mon night and especially Tue as potent mid level trough/low lifts NE across the Gt Lakes. Ptype mostly rain but ECMWF has low level cold air lingering into Tue morning across interior MA where some wintry mix/ice may continue before precip quickly changes to rain. Models indicate a strong pre-frontal low level jet which will advect high PWAT airmass northward into New Eng. PWAT and low level wind anomalies around +2SD which suggest potential for heavy rainfall and gusty winds. As previous forecaster noted, some convection also possible given steep mid level lapse rates. However, system is progressive which should limit excessive rainfall potential. Still, deterministic GFS/ECMWF/GGEM all indicate potential for 1"+ QPF and EPS has moderate probs of 1 inch rainfall. Temps may reach into the 50s in the coastal plain with 40s elsewhere. Wednesday and Thursday... Blustery and colder weather expected but dry conditions with NW flow. GEFS and EPS mean 850 mb temps around -8C Wed and -10C Thu so near seasonable temps expected, perhaps a bit below normal Thu. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/...
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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 Saturday/...High confidence. Through 12Z...VFR. May see spotty MVFR CIGS in a few locations across the mid and outer Cape as well as parts of N CT and the mid and lower CT valley through 12Z. Today...VFR. Any leftover MVFR CIGS should improve by 14Z. May see some SCT-BKN clouds at around 3500 ft at times around midday. Tonight and Saturday...VFR. W-SW winds increase late tonight and Saturday morning. May see sustained winds up to 20-25 kt and gusts up to 30-35 kt, with best chance along the S coast, Cape Cod and the islands as well as the inland higher terrain. KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF. Outlook /Saturday Night through Tuesday/... Saturday Night: VFR. Breezy. Sunday through Sunday Night: VFR. Monday: Mainly VFR, with local MVFR/IFR possible. Chance RA, chance SN in the afternoon. Monday Night: Mainly MVFR, with areas IFR possible. Breezy. RA likely. Chance SN, FZRA, PL interior. Tuesday: Mainly MVFR, with local IFR possible. Windy with gusts to 30 kt. RA.
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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 Term /through Saturday/...High confidence. Winds have diminished briefly early this morning across the waters so have ended Small Crafts through the morning. Strong low level wind jets will cross the waters starting around midday today through Saturday. With the W-SW winds in place, will see winds increase especially late tonight and Saturday. Have issued Small Craft Advisories from this afternoon through around midnight tonight, which will transition to Gale Watches for the outer waters as well as the southern bays and sounds late tonight and Saturday. Could see gusts up to 35-40 kt in the gale watch areas. Seas may build as high as 6-9 ft, highest across the southern waters during Saturday. Outlook /Saturday Night through Tuesday/... Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Sunday through Monday: Winds less than 25 kt. Seas locally approaching 5 ft. Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Rain likely. Tuesday: Low risk for gale force winds with gusts up to 35 kt. Rough seas up to 12 ft. Rain.
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&& .HYDROLOGY... A Flood Warning remains in effect for the Connecticut River at Middle Haddam, where ice jams are causing river fluctuations. For details on specific area rivers, including observed and forecast river stages, please visit the Advanced Hydrologic Prediction Service (AHPS) graphs on our website. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Gale Watch from Saturday morning through Saturday afternoon for ANZ232>235-237-250. Small Craft Advisory from 1 AM to 8 AM EST Saturday for ANZ232>234. Small Craft Advisory from 7 AM to 4 PM EST Saturday for ANZ230. Small Craft Advisory from 1 AM to 5 PM EST Saturday for ANZ231. Small Craft Advisory from 2 AM to 4 PM EST Saturday for ANZ236. Small Craft Advisory from 10 PM this evening to 8 AM EST Saturday for ANZ235-237. Small Craft Advisory from midnight tonight to 8 AM EST Saturday for ANZ250. Small Craft Advisory from 2 AM to 7 PM EST Saturday for ANZ251. Gale Watch from late tonight through Saturday evening for ANZ254. Small Craft Advisory from noon today to 5 AM EST Saturday for ANZ254. Gale Watch from late tonight through Saturday evening for ANZ255-256. Small Craft Advisory from noon today to 3 AM EST Saturday for ANZ255-256.
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&& $$ SYNOPSIS...KJC/EVT NEAR TERM...EVT SHORT TERM...EVT LONG TERM...KJC AVIATION...KJC/EVT MARINE...KJC/EVT HYDROLOGY...Staff

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