Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 290546 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 146 AM EDT SUN MAY 29 2016 .SYNOPSIS... The Memorial Day weekend will continue to see well above normal temperatures with daytime max temps between 10 to 20 degrees above normal. Increasing low level moisture will allow for higher relative humidities and an increasing chance for widespread showers with scattered thunderstorms possible on Sunday and Memorial Day. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 142 AM EDT Sunday...No significant changes needed to current forecast, with warm conditions continuing late this evening (temps mainly in the low-mid 70s at 10pm). With the 2pm observation in Burlington we reached 90 degrees for the second day in a row putting us two thirds of a way to a local heat wave. Expect warm and moderately humid conditions through the overnight period. Despite some aftn and early evening towering Cu across the higher terrain, anticyclonic flow aloft with strong mid-level ridge in place across NY/New England precluding any convective initiation with lack of large-scale forcing for ascent. Anticipate some patchy fog/mist across the valleys of northern NY after midnight tonight, similar to what occurred during the pre- dawn hrs this morning. Lack of rainfall in recent days will generally limit areal extent of fog formation. Overnight low temperatures generally in the low to mid 60s. For Sunday, mid-level shortwave trough crossing the Eastern Great Lakes induces height falls by afternoon across Northern NY/VT, with better chance for afternoon shower and thunderstorm development as compared to the previous 2-3 days. There will be a large influx of precipitable water with values rising to 1.6-1.8". 925mb temps are elevated again Sunday and the 21-23C 925mb temps will support max temps tomorrow once again in the upper 80s to low 90s. Currently the forecast for Burlington reaches heat wave criteria with a max temps of 90 expected. Should remain dry with partly to mostly sunny for the morning hours, then will see scattered shower/thunderstorm development mainly after 17-18Z, with initial development likely starting across the Eastern slopes of the Adirondacks and moving Eastward into the Champlain Valley and into Southern VT, per 18Z NAM4KM. MUCAPE values are expected to reach 1000-2000 J/kg during the peak daytime heating hours. With the chance for thunderstorm development, slow storm motions, and PWAT values 1.6-1.8", continued to mention the chance for heavy rain in any thunderstorms that develop. We should be safe with regards to flash flooding owing to how dry we`ve been in May but locally heavy downpours and dangerous cloud to ground lightning can be expected with the scattered convective storms expected Sunday afternoon into early Sunday evening. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... As of 427 PM EDT Saturday...precipitable water values early Sunday night will be 1.5 to 2 inches. Will mention showers and thunderstorms for Sunday night, and will include some heavy rainfall possible with any thunderstorms. Conditions quite dry across the region in May, so do not expect any flash flood issues at this time. ECMWF and GFS models now showing frontal system will move through the region earlier in the day on Monday with showers mainly Monday morning, as both models showing a mid level dry slot will move into the region by 18z Monday. Thus, have decreased pops for Monday afternoon, and will go with a dry forecast for Monday night. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 427 PM EDT Saturday...Fair and dry weather will be over the north country from Tuesday through Thursday night, as a ridge of high pressure at the surface and aloft builds east from the Great Lakes. ECMWF and GFS models in fairly good agreement with bring a cold front from the Great Lakes into the region with showers expected Friday and Friday night. ECMWF and GFS models differ on forecast for Saturday, with the ECMWF model more progressive than the GFS and has a mainly dry forecast for Saturday, while the GFS model has the front stalled across the region on Saturday as it will be parallel to the upper flow. Thus, forecaster confidence for the Saturday forecast is low at this time. Have stuck with super-blend pops for Saturday and will have a chance of showers in the forecast for Saturday. && .AVIATION /06Z Sunday THROUGH Thursday/... Through 06z Monday... Generally VFR with overnight IFR/LIFR mist at SLK and possibly at MPV. Increasing risk for sct SHRA/TSRA particularly after 16z Sunday at our NY terminals. Similar to last night with some leftover high clouds. Areas of mist likely starting at 06z at SLK. Boundary- layer flow is slightly higher enough at mpv to keep any mist that may develop there temporary. Winds initially light/terrain driven becoming calm. Any mist/light fog lifts early in the morning under strong sunshine. Additional heating and increasing depth of moisture should support at least scattered showers/possible storms. Latest short-term guidance points to a start time around 16z off the Adirondacks and then advancing eastward. Any thunderstorm capable of heavy rain and associated brief IFR visibilities. Maintained VCSH for this period with prevailing VFR conditions. Winds becoming south/southwest 5-8 kts. Outlook 06z Monday through Thursday... Mainly VFR with daily chances for showers and thunderstorms each afternoon and evening. Greatest coverage/threat appears to occur in the Monday early evening time frame. Best chance for a dry day will be Wednesday. && .CLIMATE... Record maximum temperatures for Saturday 5/28 and Sunday 5/29 are as follows: 5/28 5/29 BTV - Burlington 92 in 1978 89 in 1978 MPV - Montpelier 88 in 1978 87 in 1978 MSS - Massena 89 in 1978 90 in 1978 St Johnsbury 93 in 1978 92 in 1978 Mt Mansfield 77 in 1978 77 in 1978 && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Deal NEAR TERM...Banacos/Deal/Neiles SHORT TERM...WGH LONG TERM...WGH AVIATION...Neiles CLIMATE...BTV is the U.S. government's official web portal to all federal, state and local government web resources and services.