Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 241340 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 940 AM EDT Fri Mar 24 2017 .SYNOPSIS... An active weather pattern is expected for the next several days across the entire North Country. A wide variety of precipitation types are also expected with snow changing to rain today through tonight...but not before some light snow accumulations occur. There may even be some sleet mixed in. The precipitation will push south of the area on Saturday...but then returns late Saturday night and continues Sunday into Monday. Once again we will be looking at a mix of rain...sleet...and snow. && .NEAR TERM /THROUGH SATURDAY/...
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As of 940 AM EDT Friday...Some modest adjustments to current forecast to speed of timing/arrival of snows across the area. Also nudged QPF/snowfall amounts up just slightly from prior forecast, though still offer a general 0.5 to 2 inches for valleys today, 2 to 4 inches in the mountains with localized totals to perhaps 6 inches in the highest elevations. Didn`t get too carried away with some of the higher model QPF output given a distinct high bias during warm advective events. Used latest RAP model for mid level thermal profiles and slightly cooler model-blended hourly temperature trends given expected wet bulbing processes. This would offer highs mainly in the lower to mid 30s across north central/northeastern VT and upper 30s to lower 40s elsewhere. Prior discussion... Clouds will continue to be on the increase today as a warm front approaches the region. Favorable warm air advection will take place for widespread precipitation to develop across the area...especially this afternoon into the first half of tonight. However...there will be one narrow band of snow that moves across the area this morning. Low dew points across the area this morning should help temperatures cool briefly at the onset of precipitation before warming above freezing later today into early tonight. Thus looking at snow changing to rain later today...with temperatures remaining cold enough over parts of eastern Vermont for the precipitation to remain as snow with even some sleet mixing in as warmer temperatures aloft move across the region. Most locations should see a half to two inches...with higher amounts in the mountains and over north central and northeast Vermont where two to four inches is more likely. Northwest flow aloft takes over late tonight and warm front will begin to get shunted to the south after midnight tonight and colder and drier air will begin to move out of Canada and down into the far northern portions of New York and Vermont. High temperatures today will be in the mid 30s to lower 40s with lows tonight in the mid 20s north to mid 30s south. On Saturday...colder and drier air continues to push south during the day and any precipitation will be most concentrated over the central and southern sections of our area with front pushing southward. Highs will be in the mid 30s to lower 40s and thermal profile suggests a mix of precipitation types once again with rain...sleet...and snow possible.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 415 AM EDT Friday....Initially Saturday evening the cold front that will have caused the precip on Friday will sag south of the North Country and should lead to a brief period of dry weather. However that will be short lived as the high pressure over the Hudson Bay builds east. As that does, the flow will become southerly and push the front back to the north with a reinvigorating shot of cold air and precip. Expect snow initially as we wet bulb down and cool however the southerly warm air will eventually win out, and we see a transition from snow with wintry mix, and then to plain rain but Sunday during the daytime hours. There could be a few pockets of freezing rain but with the warm air pushing in from the south and the high sun angle its climatologically difficult to see much freezing rain in late March. While boundary layer temps melt all the precip to mainly rain during the day on Sunday, as we cool overnight we return to the mixed bag of precip. The warm nose looks strongest over the Saint Lawrence and Champlain valleys however east of the Greens 925mb temps stay below zero. The result is that I anticipate mainly rain with some ice pellets for the Greens and west however east of the spine of the Greens we`ll be looking at a messy wintry mix. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 415 AM EDT Friday...The pattern continues to be messy moving into the work week next week. As the first of a series of upper level troughs swings through off and on rain/snow will persist through Monday night before briefly subsiding. Then the next trough swings through bringing more rain and snow Tuesday into Wednesday. The difficulty in the forecast is that the thermal profiles are very close to the rain or snow line so slight movement north or south of the low pressure systems will have dramatic impacts on precip type. So I`ve gone with the boundary layer idea of rain/snow based primarily on surface temp for now but will update as temps aloft become clearer. The general trend in temperatures is that we are finally truly coming out of winter as the airmasses are becoming more Pacific than Arctic. Thus we will see a generally warming trend that puts out temps near normal with highs in the 40s and lows in the 30s. With the exception of Monday night and temps in the mid to upper 30s overnight, the diurnal swings should be good for the maple sap runs. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... Through 12Z Saturday...Overall expect VFR conditions through about 14z before ceilings and visibilities lower through the remainder of the period. However...there will be a narrow band of snow moving across the area that reduces visibilities down to a mile and ceilings to around 1000 feet for less than one hour through 13z. Otherwise looking at MVFR/IFR conditions developing over the entire area...especially after 18z and continuing through the remainder of the period. Precipitation will begin as snow and then transition over to rain between 21z and 00z. Light winds through 12z before increasing out of the south with gusts in the 15 to 20 knot range at most locations later this morning and afternoon. Winds will start to shift to the west and north after 06z. Outlook 12Z Saturday through Tuesday... 12Z Saturday through 18Z Saturday...MVFR/IFR conditions expected to improve as precipitation settles southward and lessening in coverage by Saturday afternoon affecting mainly southern terminals at that point. Highest threat of mix to occur at northern terminals. 18Z Saturday through 12Z Sunday...trending mainly VFR /precipitation-free as Canadian high pressure noses briefly southward into the area. 12Z Sunday through 12Z Tuesday...widespread mixed precipitation and/or rain return to the region. 12Z Tuesday onward...light and spotty mixed precipitation transitions toward a period of steadier rains by Wednesday. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Evenson NEAR TERM...Evenson/JMG SHORT TERM...Evenson LONG TERM...Deal AVIATION...Evenson/KGM is the U.S. government's official web portal to all federal, state and local government web resources and services.