Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 211959 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 259 PM 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 1223 PM EST Wednesday...Updated to capture latest trends in clouds/temps and dwpts. Current satl pic shows a sharp line of clouds moving into central/northern VT attm with the actual sfc boundary across western dacks. Temps will drop 5 to 8 degrees with increasing clouds and another 10 to 15 degrees with the actual boundary this aftn. A brief rain shower with qpf less than a tenth of an inch is expected with fropa. Have continued to mention highest pops in the northern dacks into the northern/central greens this aftn. Also, have tried to integrate latest obs into hourly temp fields to capture trends. Both MPV/BTV have reached 69 with 70 at Rutland. RER has been updated. Hydro update...continuing to see river rises from significant snowmelt at mid/upper elevations this aftn...with some isolated ice jam related flooding on the Ausable, Salmon, Great Chazy, and Winooski. Still watching the Lamoille, Passumpsic, and Missisquoi very closely given latest hydro graph trends showing sharp rises for the potential ice jam related flooding. Previous discussion below: 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/...
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As of 257 PM EST Wednesday...A deep subtropical high over Florida will lead to a persistent and mild WSW flow aloft through the long term period. High pressure over the east will lead to a rather mild day on Saturday with highs in the 40s before the next round of precipitation moves in later in the evening. A strong low pressure moving out from CO through the western Great Lakes early Sunday morning before finally moving into James Bay Canada Sunday night. The associated occluded frontal system and precipitation will move through the North Country late Saturday into Sunday. While we`ll be on the warm side of that system, with the arrival overnight and below freezing temps across area at that time, we can expect a wintry mix, especially across northern NY, of snow/sleet and freezing rain. By mid morning, temps bounce back above freezing, changing precipitation over to rain, though NEK could hold on to a mix until later in the day Sun. 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, though a wind advisory isn`t of the question for part of the day Sunday. Looking into next week, things look a little drier and slightly cooler Monday and Tuesday with ridging aloft and a NW flow, but highs will still be above seasonal normals, upper 30s to lower 40s with lows overnight in the mostly in the mid 20s to low 30s.
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&& .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... Through 18Z Thursday...A brief shot of MVFR/IFR conditions is moving through NY with the frontal passage as some light rain falls but will quickly become VFR on the back side of the front as drier air returns to the region. Expect VFR conditions to prevail through overnight hours into tomorrow with some gusty southwesterly winds at KBTV/KMPV/KRUT this evening switching to northwesterly after 00Z. Outlook... 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 areas VFR 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. Sunday Night: VFR. Chance SHSN, Chance SHRA. Monday: VFR. Chance SHRA, Chance SHSN. && .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...
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VT...Flood Watch through Thursday morning for VTZ001>012-016>019. NY...Flood Watch through Thursday morning for NYZ026>031-034-035- 087.
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&& $$ SYNOPSIS...Clay NEAR TERM...Clay/Taber SHORT TERM...Sisson LONG TERM...Verasamy AVIATION...Verasamy 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.