Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 211133 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 633 AM EST Wed Feb 21 2018 .SYNOPSIS... Record breaking warm temperatures are expected today which will cause significant snow melt and sharp rises on local streams and rivers. Areas of ice jam flooding are possible through Wednesday night. Scattered rain showers will be seen as a cold front will push through the area this afternoon. Temperatures will quickly drop temperatures back into the 20s and 30s tonight with drier conditions expected on Thursday and Friday. && .NEAR TERM /THROUGH THURSDAY/... As of 410 AM EST Wednesday...Temperatures have been on the rise this morning with KBTV already setting a record high temperature of 60 degrees shortly after midnight. A few cold pockets have been observed across the state with locations like Plattsburgh and Springfield in the 40s and 30s respectively while most other sites are in the 50s and 60s. The few locations that have proven stubborn with the colder temperatures will mix out prior to the frontal passage with temperatures quickly warming into the mid 50s to mid 60s. With the unseasonably warm start to the day, it`s quite likely that temperatures across much of the state will warm into the mid to upper 60s while some locations from Burlington southward may see temperature approach and possibly top the 70 degree mark. However, a cold front will push through the North Country this afternoon and inhibit the extent of how warm it will get today due to the frontal passage occurring prior to peak heating. Even so, record high temperatures are all but certain across much of the forecast area before temperatures drop back below freezing tonight. Although PWAT values are in the 1 to 1.4 inch range (which is 3 to 4 standard deviations above normal), the lack of synoptic forcing will likely lead to just some scattered rain showers throughout the morning and afternoon hours before drier air filters in behind the front. The main concern today will be the potential for localized flooding due to ice jams. There was an ice jam near Ausable Forks for a large portion of the overnight hours but it released around 3:30 AM. Additional flooding from ice jams is possible today and tonight as snow continues to melt from the mountains and flows into the main stem rivers and interacts with pre- existing ice jams from the previous warm up in January. The good news is there should only be another 0.05 to 0.15 inches of rainfall today with the frontal passage; so additional rainfall should not complicate matters further. For Thursday...more seasonable, yet slightly above normal, temperatures will be observed. A weak shortwave will rotate around the Bermuda High and bring a chance of snowfall to Rutland and Windsor counties but most of the snowfall is expected to stay well south of the area. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 410 AM EST Wednesday...Friday night looks quiet with 1040 mb high pressure center moving across southern Quebec. With clear skies to partly cloudy skies temps should fall into the teens with the normal cold spots down in to the single numbers. The next system quickly approaches from the southwest on Friday with some overrunning warm advection precipitation by afternoon. the 850mb zero line moves north of the region by evening on the nose of a 40 kt SW flow. It looks like temperatures will warm surface and aloft so it will be mostly a snow or mix changing to rain type of event. QPF looks light perhaps 0.10-0.30" event with perhaps an inch of snow mainly in northeast VT. High temps on Friday mainly in the 30s. Friday night most of the precip will have moved out, but with some weak cold advection as another weaker high pressure system moves into Quebec. Lows mainly the upper 20s to lower 30s, well above normal for this time of year. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 410 AM EST Wednesday...A persistent and mild WSW flow aloft is expected through the period with a deep subtropical high over Florida. High pressure and ridging aloft over the east will bring quiet mild day on Saturday with highs in the 40s. Meanwhile a rather strong 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 through the North Country during Sunday. We`ll be on the warm side of that system as well as temperature profiles warm above freezing right up through 850 mb so any mixed rain and snow will change to rain once again. The winds should be stronger on Sunday as we see some downsloping developing. Anticipate 20-25kts with gusts of 25-35kts along the western slopes of the Greens and the northern slopes of the Adirondacks. It does look a little drier and slightly cooler Monday and Tuesday with ridging aloft and a NW flow, but still looking at highs in the upper 30s to lower 40s with lows overnight in the mostly in the mid 20s to low 30s, continuing above normal. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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Through 12Z Thursday...VFR conditions prevail across all TAF sites this morning with a warm front to our north and a cold front to our west. A brief shot of MVFR conditions are expected with the frontal passage as some light rain falls but will quickly become VFR on the back side of the front as drier returns to the region. A stout low level jet upwards of 50 kt at 2kft will produce some wind shear out ahead of the front. Any shear will dissipate post frontal passage as the jet of stronger winds gets shunted further east. Expect VFR conditions to prevail through the evening and overnight hours with some gusty northerly winds at KBTV/KMPV. Outlook... Thursday: VFR. Slight chance SHSN. Thursday Night: VFR. NO SIG WX. Friday: Mainly VFR, with local MVFR possible. Likely RA, Chance SN. Friday Night: Mainly MVFR, with local IFR possible. Likely SN, Likely RA, Chance SHSN. Saturday: Mainly MVFR, with local IFR possible. Chance SHRA, Chance SHSN. Saturday Night: Mainly VFR, with local MVFR possible. Chance SN, Chance SHSN. Sunday: Mainly MVFR and IFR, with local VFR possible. Likely RA, Likely SN.
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&& .HYDROLOGY... As of 410 AM EST Wednesday...Record-breaking warmth will continue across the area today with record-breaking high temperatures in the 60s to near 70 in some locales. Despite relatively light rainfall, moist winds and dewpoint temperatures in the 40s to lower 50s will continue to foster rapid snowmelt and ice break- up across the entire area. Also boosting confidence are extremely high thawing degree hour totals with two day totals by later today averaging from 900 to 1200. As a result, modest to substantial river rises are occurring and will continue into this evening supported by NAEFS/SREF MMEFS hydrograph data and reflected in our latest river forecasts. While widespread open water flooding is not expected, several rivers may approach minor flood. More importantly, numerous ice jams remain in place from the substantial thaw this past January so the potential for localized high water and/or flooding near these features remain a real threat as ice break-up occurs. && .CLIMATE... Here are the current record high temperatures for today: BTV................60* (2018)... MPV................57 (1953)... MSS................62 (1953)... St. Johnsbury......62 (1981)... *Site hit record high temperature early this morning with temperatures continuing to rise through this afternoon. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Flood Watch through this evening for VTZ001>012-016>019. NY...Flood Watch through this evening for NYZ026>031-034-035-087. && $$ SYNOPSIS...Clay NEAR TERM...Clay SHORT TERM...Sisson LONG TERM...Sisson AVIATION...Clay HYDROLOGY...TEAM BTV CLIMATE...TEAM BTV is the U.S. government's official web portal to all federal, state and local government web resources and services.