Area Forecast Discussion
Issued by NWS Burlington, VT

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139 FXUS61 KBTV 132354 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 754 PM EDT Sun Jul 13 2025 .SYNOPSIS... Summer heat and humidity is fueling showers and thunderstorms as a cold front slowly approaches from the west. Stronger thunderstorms through this evening will likely lead to a few instances of flash flooding and damaging winds in northern New York, while heavy rainfall will be possible with all thunderstorms through tomorrow. While dry weather returns for Tuesday, heat will build midweek, peaking Wednesday, before another Thursday with thunderstorm chances leads to a quieter and less hot period to close out the week. && .NEAR TERM /THROUGH MONDAY NIGHT/... As of 309 PM EDT Sunday...Busy convective weather, with both severe and flash flooding concerns, through this evening, while the threat of heavy rainfall lessens a bit overnight into tomorrow in our region. Robust moisture and heat are present this afternoon along with a subtle upper level shortwave kicking northeastward ahead of a cold front. The axis of greatest instability, featuring around 2500 J/kg mixed layer CAPE, has been over the St. Lawrence Valley where widespread thunderstorm activity developed by 2 PM. Meanwhile the axis of maximum precipitable water is offset just to the west at over 2", near and just ahead of another quasi-linear area of convection in southern Ontario heading towards northern New York. The expectation is for rounds of thunderstorms to slowly move towards the east through this evening, with eastward progress driven by outflow as the mean 850- 300 millibar flow remains largely parallel to the front/running, from southwest to northeast. The strongest convection capable of damaging winds should remain mainly within the corridor where a Storm Prediction Center slight risk (level 2 of 5) of severe thunderstorms exists, over much of northern New York and extreme northwestern Vermont. With limited deep layer shear peaking near 25-30 knots, storm organization will be limited, which suggests mainly isolated/lower coverage of damaging wind to localized wet microbursts and perhaps small bow echoes. That being said, with widespread coverage of thunderstorms, the potential for some impacts through tonight is high; stay weather aware. As we move into tonight, ongoing convection will weaken a bit with considerable decrease in instability as it moves through Vermont during the late evening hours. That being said, with such a juicy environment featuring soundings of tall, skinny CAPE with elevated convection, threat of localized heavy rainfall in any showers will remain. The cold front will still lag behind, such that after sunrise there will be some good heating and reinvigoration of instability across Vermont. HREF mean SBCAPE values by 2 PM increase into the 1250-1750 J/kg range, supporting additional heavy thunderstorms with a low risk of severe winds; focus of stronger convection and higher instability will be displaced south of our region. As winds turn more westerly through the day, some modest air mass change will occur leading to less hot conditions. In western areas that have more time to advect in drier air, temperatures will be a bit warmer with lower humidity. For now, we have no mention of fog for tomorrow night, but may need to add in future forecasts as large scale pattern with abundant rain and limited drying, light winds and clearing skies will support this potential for quite a bit of dense fog. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 203 PM EDT Sunday...No impactful weather is expected on Tuesday as a weak ridge of high pressure moves overhead and precipitation chances are very low. Seasonably hot conditions will lead to typically high wet bulb globe temperatures, indicative of plenty of sunshine, moderate humidity, and light winds, as temperatures warm into the mid 80s to low 90s with similar heat index values. WPC Heat Risk values will be largely in the moderate range as well given mid- summer conditions. The air mass aloft will become a bit warmer overnight, but with light winds most areas outside of the wide valleys should manage to cool off well with a nocturnal inversion developing, leading to lows in the upper 50s to mid 60s in most locations. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 203 PM EDT Sunday...Heat and humidity will continue mid to late week with a ridge cresting over the easter CONUS. Heat will peak on Wednesday with 925mb temperatures trending higher towards 25-27C. Dewpoints will reach into the mid to upper 60s which will drive heat index values into heat advisory criteria. The ridge looks to weaken as a shortwave will draw some troughing across the area Wednesday night into Thursday. Timing and amplification of this initial shortwave remains in question, however, it should lead to more parallel flow across northern New York behind it which will help slow an associated frontal system. This set up looks similar to today and the event last Thursday where a slow moving frontal system pools moisture leading to heavy rain. Current Pwat forecasts show values near 1.5-2," which will need further monitoring given recent heavy rain events. Ensembles indicate the front should finally clear out by Friday evening though the air mass behind it, while offering some relief, will still feature at or above seasonable temperatures. Dewpoints look to fall into the lower 60s for the weekend. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
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Through 00Z Tuesday...Currently all terminals are VFR ahead of a cold front, with clusters of showers and thunderstorms stretching across northern New York and northwestern Vermont. Within the heavier showers, there will be temporary IFR conditions. Through the next six hours this should be primarily at Vermont TAF sites as most of the stronger convection is pushing northeastward out of the Adirondacks. There are additional showers trailing behind in northern New York with generally VFR visibilities and ceilings. While MVFR ceilings are favored at sites like EFK and MPV towards daybreak as some lowering of ceilings occurs behind the heavy rain tonight, there should be enough southwesterly flow off the deck to help scour out the near surface moisture. Otherwise mainly VFR conditions should persist. Winds have diminished with the precipitation moving into the area, but will tend to remain southerly through at least 12Z. In northern New York a wind shift to westerly will occur after that time with the cold frontal passage. Farther east, winds will turn westerly towards 15-20Z, leading to a window of at least a few hours in which showers and possibly a thunderstorm may develop. Outlook... Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. Slight chance SHRA, Slight chance TSRA. Wednesday Night: VFR. Slight chance SHRA, Slight chance TSRA. Thursday: VFR. Likely SHRA, Chance TSRA. Thursday Night: MVFR/IFR conditions possible. Chance SHRA, Slight chance TSRA. Friday: Mainly MVFR, with local IFR possible. Chance SHRA, Slight chance TSRA.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Kutikoff NEAR TERM...Kutikoff SHORT TERM...Kutikoff LONG TERM...Danzig AVIATION...Danzig/Kutikoff