Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 260027 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 727 PM EST Sat Feb 25 2017 .SYNOPSIS... A strong cold front will continue move eastward across the North Country this afternoon and early evening. The leading edge of the front will have strong gusty winds and heavy rain. Rain will continue behind the front continuing the potential for ice jams and river flooding through the weekend. Tonight, lingering snow showers concentrated over the higher terrain will taper off Sunday morning. More seasonable weather returns Sunday with some light snow in the higher elevations before a quieter period of weather to start the work week. && .NEAR TERM /THROUGH SUNDAY/... As of 318 PM EST Saturday...Strong cold front moving through Northern New York this afternoon has produced strong gusty winds, heavy rain and isolated lightning/thunder. Gusty winds out ahead of the front from strong 850mb jet...CXX VWP showing 50kts at 850mb has also helped with deeper mixing and strong WAA, resulting in temperatures in the 60s to around 70. Expect the leading edge of to reach the Champlain Valley around 22Z, continuing east into central VT around 00Z and eastern VT shortly thereafter. The very warm temperatures and the heavy rain that is moving eastward across the area will continue the flood threat. Already have some areas/rivers flooding (see FLW`s) and expect the rain this afternoon and evening to result in runoff reaching the rivers and rivers cresting on Sunday. Observed 6-hourly rainfall amounts have generally ranged from quarter inch to half inch. Rain will continue with still some embedded areas of moderate to heavy rain possible into this evening. Expect the back edge to move out of the SLV around 03Z, CPV after midnight/05z. Lingering precipitation focused around the higher terrain is expected through Sunday morning. Also behind the front, the cold air advection surges in and we will see 25-35 degree diurnal swings with lows in the mid-upper 20s expected. Thus the precip lingering behind the anafront will likely end as end as a period of rain/snow in the valleys and heavy wet snow in the higher elevations where several inches of accumulation are possible. Sunday, some gusty winds of 30kts or less are possible in lingering PGF before subsiding in the afternoon. Drier air will move in with slight ridging at the surface. Max temperatures in decreasing cloud cover will generally be in the 30s. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 318 PM EST Saturday...Ridging at the surface continues Sunday night, but a mid level shortwave will near the international border Monday morning. Models disagree how far south the shortwave will reach, but with limited moisture available, have kept only slight chance POPs throughout the period, mainly for higher terrain near the international border. With increased cloud cover possible from the shortwave and generally moderating temperatures as low level flow becomes for SW, expect min temperatures Sunday night to be in the 20s. Increasing 500mb heights indicative of continued moderating temperatures in SW flow on the NW edge of surface ridge will have Monday and Monday night dry with max temperatures in the 40s and mins in the 20s. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 318 PM EST Saturday...Tuesday the area will remain under slight ridging aloft, but moisture and weak vorticity attempt to move in from the south. NAM and GFS in agreement bringing precipitation into at least the southern half of the forecast area Tuesday afternoon, while ECMWF wait for developing low to bring precipitation Tuesday night-Wednesday. This system associated with deepening 500mb trough over the northern plains states. Details of track of developing surface low and strength continue to be under debate. Overall 12Z GFS and ECMWF show the surface low to track near the international border, which could start precip as rain through most of Thursday before the associated cold front moves through. Lingering snow showers possible late Thursday. Overall still time for models to focus around a solution. && .AVIATION /00Z Sunday THROUGH Thursday/... Through 00Z Monday...A strong cold front is moving through Vermont as of 00Z Sunday. Expecting rain with this cold front to come to an end by 06Z Sunday. Rain has already changed to snow over the Adirondacks in northern New York as of 00Z Sunday, especially at KSLK. Expecting areas of MVFR/IFR through 06Z Sunday, with areas of MVFR/VFR after 06Z Sunday. Expecting west-northwest surface wind gusts at or above 20 knots through the period. Outlook 00Z Monday through Thursday... 18Z Sunday - 12Z Tuesday...Mainly VFR under high pressure. 12Z Tuesday - 00Z Thursday...VFR with chance MVFR/IFR rain showers. 00Z Thursday - 00Z Friday...areas of MVFR in rain showers ahead of a cold front. && .HYDROLOGY... As of 430 AM EST Saturday...Rivers seeing rises with snowmelt and ice jams on northern rivers. Missisquoi River jams causing high water at a few spots along that river and have issued a flood warning for Franklin County along the river for the jams. Great Chazy showing some ice impacts with locals reporting a jam in place at Perry Mills but water finding a way through. East Branch Ausable at Ausable Forks NY jam has moved downstream and has come to rest near Chester NY with no effect according to Emergency Management. Passumpsic river also at risk for ice jams but no ice movement yet reported there. Ice jams possible anywhere there is a constriction in the river such as a bend or bridge abutment to stop ice movement. Thunderstorms and rain moving into area will combine with ongoing snowmelt produced by record setting temperatures to transition this to an open water minor flood event. Have already issued flood warnings for flooding for East Branch Ausable at Ausable Forks and Otter Creek at Center Rutland to exceed flood stage later tonight. Both gages only a couple feet below flood stage at issuance. Watching Winooski basin for rain/snowmelt flooding as well but holding off on warnings at the moment until we see the rainfall amounts. Missisquoi also at risk of open water flooding possibly at North Troy VT where ice is not present. Lamoille River less of a flood threat as it is starting at lower levels, and forecast to see mainly within-bank rises. Most river rises overnight with crests after midnight into mid day Sunday. && .CLIMATE... Several more record high temperatures are expected to be broken tomorrow on February 25, 2017. Here are the current records for our long standing sites: Burlington, VT 55|1985 Montpelier, VT 59|1985 St. Johnsbury, VT 60|2016 Massena, NY 50|1956 Mount Mansfield, VT 49|1961 && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Flood Watch through Sunday evening for VTZ001>012-016>019. NY...Flood Watch through Sunday evening for NYZ026>031-034-035-087. && $$ SYNOPSIS...Deal/KGM NEAR TERM...JMG/KGM SHORT TERM...KGM LONG TERM...Evenson/KGM AVIATION...Evenson/WGH HYDROLOGY...Hanson CLIMATE...Lahiff is the U.S. government's official web portal to all federal, state and local government web resources and services.