Area Forecast Discussion
Issued by NWS Burlington, VT

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750 FXUS61 KBTV 221759 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 1259 PM EST Thu Feb 22 2018 .SYNOPSIS... Cloud cover will increase today as a weak system brings a chance of snowfall to southern Vermont this afternoon. Clouds will then decrease through the overnight hours with temperatures returning to near normal values. Temperatures will then quickly warm on Friday as another system moves toward the area. Precipitation will build across the region late Friday morning with a transition from snow to sleet to rain expected but no impacts are expected with this system as it quickly exits the region Friday night. && .NEAR TERM /THROUGH FRIDAY/... As of 1218 PM EST Thursday...Very minor update to capture latest trends in temps/dwpts and winds. Still expecting a period of light snow across Rutland/Windsor Counties between 18z-21z this aftn...which is confirmed by latest radar trends. The combination of deeper moisture and lift from 700mb fgen forcing will help saturate low levels enough to produce this light snow. Otherwise...a few flurries possible over central vt into the high peaks with mostly cloudy skies prevailing. Temps holding steady in the upper 20s to mid 30s. Previous discussion below: Temperatures have been slower to fall than originally expected as quite a bit of mid and high level clouds continue to push across the region. In addition, the majority of the cold air advection seems to have lagged a bit behind the cold front with Canadian observations showing temperatures just in the low 20s. Skies will clear toward morning and as the temperatures at 850mb and 925 mb continue to cool, our low temperatures should be observed just after sunrise. An impressive fetch of southwesterly flow aloft continues to advect moisture from the Gulf of Mexico up toward the North Country. The strong Bermuda High that brought record warmth to much of New England yesterday has now retreated slightly to the southeast but 850/700/500 heights still remain well above normal for this time of the year. The way that the longwave pattern has set up with the aforementioned southwesterly flow aloft will continue to bring several short waves through New England over the next several days. The first shortwave will push south of Vermont this afternoon and a chance of snow will develop across Windsor and Rutland Counties. Much of the moisture with this system will be shunted pretty far south but some moisture will wrap around the shortwave and bring some snow near the VT/NY/MA border but Rutland and Springfield may see a dusting of snow while the remainder of the forecast area remains dry. Skies will clear on the backside of the shortwave tonight with nice subsidence suppressing cloud cover. This will lead to a true radiative cooling night where temperatures are expected to drop into the single digits to mid teens across the forecast area. Even with these colder temperatures, temperatures will remain near or slightly above normal due in large part to the anomalously high heights aloft. Temperatures will quickly warm on Friday as warmer and wetter air associated with another shortwave pushes toward New England. Precipitation type will be the forecast challenge with this system as temperatures across the board start well below freezing and warm throughout the day. A transition from snow to sleet to rain is expected as temperatures warm both aloft and at the surface. There could be some pockets of freezing rain but these look restricted to the higher elevations. Valley locations within and east of the Green Mountains will likely see periods of sleet linger through the afternoon as the cold air at the surface will likely be difficult to scour out. Overall QPF looks unimpressive with less than a tenth of an inch of liquid over most locations with slightly higher amounts over the higher terrain. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 445 AM EST Thursday...Friday night...most of the precipitation will be tapering off in the evening as the best warm advection, lift, and deeper moisture moves east rather quickly and a weak occluded front moves though the region. Precipitation type will be mainly rain as the column warms but still a bit problematic in eastern VT where some pockets of freezing temps will linger with light freezing rain. Still some uncertainty in temps being a degree or two either side of freezing. Some of the higher terrain above 2000 ft could see some snow showers by Saturday morning as colder air aloft moves in. QPF will be light with less than a tenth of an inch so not expecting much of either freezing rain or snow. High pressure over Quebec and ridging aloft moves into the region for Saturday afternoon and the first half of Sat night before the next system in the form of an warm and occluded front approaches with some increasing clouds late. More below. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 445 AM EST Thursday...A rather strong and deepening low pressure will track from CO through the western Great Lakes into James Bay Canada through Sunday night. It`s associated occluded frontal system and precipitation will move from southwest to northeast into the North Country starting early Sunday. Initially, it looks like it will be cold enough for an inch or so of snow or sleet on the leading edge bute`ll be on the warm side of that system as well as temperature profiles warm above freezing right up through 850 mb so any mix/snow will change to rain once again. The winds should be stronger on Sunday as we see some SE downsloping developing. Anticipate 20-30kts with gusts of 25-45kts along the western slopes of the Greens and the northern slopes of the Adirondacks. It does look a little drier and slightly cooler Monday through Wednesday with ridging aloft and a NW flow as high pressure moves from the midwest to the mid- Atlantic coast. There may be a few rain or snow showers especially in the higher terrain with the NW flow later Monday into Tuesday morning, but very light QPF. It will continue warmer than normal through the period with high temperatures in the upper 30s to mid 40s Sunday cooling a bit in to the 30s to near 40 with lows in the upper mid 20s to low 30s Monday then down in the 20s with a few teens Tue/Wed. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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Through 18Z Friday...Mainly VFR conditions will prevail through the TAF period with the exception of KRUT, where a quick shot of light snow could temporarily reduce conditions to MVFR between 18Z and 21Z. As the majority of the precipitation from this system will remain south of the forecast area, expect all other TAF sites to remain VFR. Light northerly winds will continue through the night and switch to southerly winds of up to 10 kt during the morning hours. Through the afternoon, southerly winds will increase to 10-15 kt with gusts up to 25 kts possible through the early afternoon. Outlook... Friday Night: Mainly MVFR, with areas VFR possible. Chance RA, Chance FZRA. Saturday: Mainly VFR, with local MVFR possible. NO SIG WX. Saturday Night: VFR. Chance SN. Sunday: Mainly MVFR and IFR, with local VFR possible. Definite RA, Definite SN. Sunday Night: Mainly VFR, with local IFR possible. Chance SHRA, Chance SHSN, Chance PL. Monday: VFR. Slight chance SHRA, Slight chance SHSN. Monday Night: Mainly VFR, with local MVFR possible. Slight chance SHSN. Tuesday: VFR. Slight chance SHRA, Slight chance SHSN.
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&& .HYDROLOGY... As of 445 AM EST Thursday...The flood watch has been cancelled as temperatures have dropped below freezing across much of New York and Vermont this morning which has helped to reduce snow melt runoff. Flooding associated with localized ice jams is still ongoing across portions of Northern New York and northern Vermont but latest hydrographs show most locations have crested and are beginning to drop. There still may be some flooding associated with ice jams today as ice jams release and re-develop downstream but the greatest potential for flooding has ended. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Clay NEAR TERM...Clay/Taber SHORT TERM...Sisson LONG TERM...Sisson AVIATION...RSD HYDROLOGY...Clay/Sisson/Neiles

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