Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 181222 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 722 AM EST Sat Nov 18 2017 .SYNOPSIS... Strong low pressure will pass through the region tonight into Sunday with widespread rainfall and milder temperatures. Rain will taper to snow showers on Sunday afternoon as much colder air surges back into the area along with gusty winds. The general weather pattern quiets down from Monday onward into much of next week with mainly dry and seasonably cold weather expected for the Thanksgiving holiday. && .NEAR TERM /THROUGH SUNDAY/...
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As of 722 AM EST Saturday...The forecast remains on track as we progress into the daylight hours. Small adjustments were made to hourly temperatures and dewpoints into late morning to match current observational trends, otherwise no other changes were needed. Have a great day. Prior discussion... Quite the variety of weather is expected over the next 36 hours as deepening low pressure tracks from the Ohio Valley into the St. Lawrence Valley by Sunday morning. From a broad perspective the overall theme of the forecast remains the same with thickening clouds expected today before widespread precipitation arrives by early evening into the overnight hours. Strengthening southerly flow and warm thermal advective processes will push boundary layer temperatures above freezing in most locales by mid to late afternoon such that mainly a steady light rain is expected. The only exception would be a brief period of mixed precipitation at onset at mountain summit level and possibly across portions of far northeastern VT. Given the strength of the synoptic background southerly flow have generally downplayed this threat however. Highs today to top out in the upper 30s to mid 40s for most spots with readings holding steady in VT overnight, and falling through the 30s toward morning across northern NY as cold front sweeps through. By Sunday the cold front surges quickly across the remainder of the forecast area, clearing well east by afternoon as the ~980 mb surface low races northeast toward the Gulf of St. Lawrence by early evening. Robust 3-hourly pressure rises behind the frontal boundary should ensure a windy afternoon as steadier rains transition to snow showers and flow trends northwesterly. Accumulations should be minor, though amounts from a dusting to 2 inches will be possible across the St. Lawrence Valley and higher terrain of the Adirondacks/Greens by early evening. Using an upward adjustment factor from 160-190 percent yields gusts into the 30 to 45 mph range with highest gusts in favored westerly downslope areas of the eastern Adirondacks and eastern Greens/CT River Valley. Temperatures will take on a typical cool-season non-diurnal trend as highs from the upper 30s to mid 40s will be reached in the morning before values slowly fall into the upper 20s to mid 30s by late afternoon.
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&& .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/... As of 330 AM EST Saturday...Sunday night will basically be the tail end of the system which brings wind and precipitation earlier in the day. Snow showers will be ending though gusty winds will continue. Expecting 20-30 mph gusts nearly everywhere as cold air advection keeps the boundary layer mixed. Lows will bottom out in the teens to 20s, so wind chills will be primarily in the single digits. Will have some lake effect snow showers on Monday in the Southern St Lawrence valley and Northern Adirondacks. High temperatures on Monday will be about ten degrees colder than seasonal normals, mainly 20s and lower 30s. Winds will remain pretty gusty on Monday and conditions will be blustery. Winds will begin to slack off towards evening with surface ridge building over the area. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 345 AM EST Saturday...Monday night through Tuesday night will feature quieter weather. Southwesterly flow will bring some warmer temperatures to the North Country. Fairly clear skies with temperatures back around seasonal normals once again. A weak cold front will cross the region on Wednesday and some light rain or snow showers are expected, especially across the higher terrain. At this point looks like very minimal impact. Thanksgiving day will be cooler and dry. Flurries are possible with westerly flow off the lakes, though nothing significant is expected. Thursday night into Friday could see another weak shortwave bring some more light rain or snow showers. No major storms on the horizon at this time. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... Through 12Z Sunday...Mainly VFR through 00Z Sunday with thickening mid/high cloud cover as light winds trend south/southeasterly at 5 to 10 kts (northeasterly at KMSS). After 00Z Sunday widespread rain affects all terminals with ceilings lowering to MVFR in the 015-025 AGL range in general. Some occasional VFR may continue at KBTV/KPBG/KRUT. Winds continue south to southeasterly from 5 to 10 kts (northeasterly at KMSS) and will trend modestly gusty into the 13 to 18 kt range at KRUT/KBTV/KPBG/KSLK terminals late. Outlook... Sunday: Mainly MVFR, with local IFR possible. Windy with gusts to 35 kt. Definite RA, Chance SHRA, Chance SHSN. Sunday Night: VFR. Chance SHSN. Monday: Mainly VFR, with local MVFR possible. Slight chance SHSN. Monday Night: Mainly VFR, with areas MVFR possible. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA, Chance SHSN. Wednesday: Mainly VFR, with local MVFR possible. Slight chance SHRA, Slight chance SHSN. && .MARINE... As of 337 AM EST Saturday...A Lake Wind Advisory is in effect for today as southerly winds increase into the 15 to 25 knot range by this afternoon and significant wave heights build into the 2 to 4 foot range with a moderate chop. These conditions may prove hazardous to those operating small craft, especially on the broad lake and in bays/inlets with southerly exposures. Gusty south winds will gradually abate tonight, though increase sharply from the northwest by Sunday as a strong cold front sweeps across the area. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...Neiles LONG TERM...Neiles AVIATION...JMG MARINE...JMG is the U.S. government's official web portal to all federal, state and local government web resources and services.