Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 240533 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 133 AM EDT Mon Jul 24 2017 .SYNOPSIS... Chances for precipitation increase tonight as an upper level trough brings widespread rain to the region during the day Monday and into Monday night. Showers will be heavy at times, especially across northern New York. Total rainfall through Monday night will range from near an inch and a half across northern New York, to three-quarters to around inch across Vermont. Overcast skies will yield unseasonably cool temperatures, with Monday afternoon highs mainly in the low to mid 60s. High pressure and warmer temperatures should return by Wednesday. However, a frontal system will bring showers and thunderstorms on Thursday. && .NEAR TERM /UNTIL 2 PM THIS AFTERNOON/... As of 1044 PM EDT Sunday...Our brief reprieve of calm weather ends overnight as an upper level low over the Great Lakes moves ewd and brings showers back to the North Country to start the work week. As the upper level low tracks towards the Saint Lawrence valley, a series of low pressure systems will bring widespread rainfall to the region. The first of those lows will move into northern New York ushering in thicker cloud cover and enhanced PWAT. Consensus of the guidance brings the PWATs to 1.5-1.6 across the Saint Lawrence valley with 1.2-1.4 across Vermont which is slightly above normal based on the ALY sounding climatology. The first showers are developing east of Lake Ontario at 0245Z, and should shift newd into St. Lawrence County over the next 1-2 hrs, before overspreading the remainder of the North Country by 12Z Monday. As the showers increase in coverage through Monday, it should be pretty much a washout across the North Country. Temps will be seasonable cold as we`ll be 15 degrees below normal (highs mainly in the low-mid 60s). Concerning the showers, with the above normal PWATs and persistent rainfall, I did keep with the previous forecaster`s idea that the rainfall will be heavy at times. As the first surface low tracks up the Saint Lawrence it should bring a burst of moderate rainfall overnight and then as the upper level low tracks closer the parent low will pivot and begin to dive southeast. This should mean that northern New York receives the most significant rainfall as the energy from the systems will be focused on that area for the longest period of time whereas eastern Vermont will see slightly less total rainfall. Between 1-2 inches will fall over northern New York with between 0.5-1 inch of rain should fall over Vermont. Flooding isn`t currently a concern because RFC flash flood guidance is nearly 2 inches in the 1 hour and between 2-3 in the 3 hour range. There should be enough instability and cold air aloft to support some embedded thunder with the showers mainly over northern New York. && .SHORT TERM /2 PM THIS AFTERNOON THROUGH WEDNESDAY/... As of 321 PM EDT Sunday...Mid-level trough over the North Country will continue producing showers on Tuesday into Tuesday evening. The trough will be replaced with high pressure Tuesday night with diminishing cloud cover allowing for possible fog development towards early Wednesday morning. At the surface, the ridge of high pressure will crest over the region early Wednesday, then slide off the New England coast during the day. Southwest flow will return, filtering in warmer air. Seasonably cold temperatures on Tuesday with maxes generally in the 60s and mins Tuesday night in the 50s will recover on Wednesday as maxes reach the mid to upper 70s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 321 PM EDT Sunday...Surface ridge continues to slide into the Atlantic as frontal system approaches the North Country from the northwest on Wednesday night. Expect this boundary to bring showers late Wednesday night through Thursday. At this point, models diverge on sensible weather Thursday night into Friday, but trending to keep precipitation and associated low further south, possibly affecting the southern half of the forecast area. GFS and ECMWF agree on another ridge of high pressure building in from Canada for the weekend. Temperatures throughout the period expected to be near normal. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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Through 06Z Tuesday...Deteriorating conditions expected across the area today into tonight as upper low pressure brings widespread rainfall to the region. Thunder threat rather low and confined to northern New York counties. Lack of expected coverage warrants ommission from NY terminal forecasts at this point. Generally looking at VFR trending MVFR at all terminals in the 09-18Z time frame as rain arrives from southwest to northeast. Brief IFR visibilities possible in heavier showers, especially in northern NY. Showers trend a bit lighter after 00Z Tuesday, though solid coverage remains across the area as cigs lower into the 005-015 AGL range (IFR/MVFR) with widespread 3-5sm br. Winds east to southeasterly through the period mainly in the 5 to 15 knot range, though occasionally gusty to 30 kts at KRUT in the 12-00Z time frame. Outlook... Monday Night: MVFR. Likely SHRA. Tuesday: VFR/MVFR. Chance SHRA. Tuesday Night: VFR. Patchy FG. Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. Slight Chance SHRA. Thursday: VFR. Likely SHRA...Slight Chance TSRA. Thursday Night: VFR. Chance SHRA. Friday: VFR. Chance SHRA.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Banacos/Deal NEAR TERM...Banacos/Deal SHORT TERM...KGM LONG TERM...KGM AVIATION...JMG

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