


Area Forecast Discussion
Issued by NWS Burlington, VT
Issued by NWS Burlington, VT
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
441 FXUS61 KBTV 120006 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 806 PM EDT Fri Jul 11 2025 .SYNOPSIS... Isolated showers and thunderstorms will diminish tonight, then redevelop on Saturday as the region remains in a humid and unstable pattern. A weak frontal passage will increase chances for showers and thunderstorms later Sunday into Monday. Drier, but continued hot and humid weather, is expected for the remainder of next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... As of 249 PM EDT Friday...For the rest of today, very isolated pulse showers will continue with limited thunderstorm development. They are primarily in northeastern/eastern Vermont this afternoon, again, near and east of a weak and nearly stationary surface front. Additionally, showers are developing over the western Champlain Valley, likely driven by typical differential heating/lake breeze convergence. The steering flow will generally be to the southeast, especially when storms are taller and tap into stronger winds aloft. With lack of upper level forcing to help maintain instability driven by surface heating, this activity should peak late afternoon trending southward with time, and die off this evening. Convection will not be strong enough to produce any significant impacts. Some patchy fog overnight is probable with light winds and seasonably humid air in place. That being said, mitigating factors include organized upstream convection over the Midwest and the associated mid and high level cloud cover that will stream across the region. Low temperatures will mainly be in the 60s, averaging about 5 to 10 degrees above normal. Heat and humidity will build further for tomorrow as 850 millibar temperatures tick up a couple degrees amid weak ridging. Confidence is moderate in maximum heat index values remaining a touch below Heat Advisory criteria. Currently NBM guidance suggests maximum heat index values in the low 90s are likely in the Champlain Valley where light southerly low level flow will minimize mixing of dry air aloft; think the HRRR tends to be overmixed and its lower humidity is not realistic, while NAM3 as typical is probably too extreme with depiction of low to mid 70 dew points during peak heating. High temperatures will range through the 80s to near 90 in the warmest spots. Aside from the heat, we will have to contend with thunderstorms again. Precipitation potential, as noted by the previous forecaster, has increased although coverage should remain isolated amid weak forcing. There is high confidence in sufficient instability and terrain driven lift to produce thunderstorms during the afternoon, primarily near/just east of the highest terrain. That being said, potential for severe weather remains low, as well, with deep layer shear only 15 to 20 knots per mean HREF values. Best overlap of CAPE and shear will tend to be over the central/southern Green Mountains. Mean SB CAPE values will peak in the 1500 to 2000 J/kg range. There is limited potential for stronger convection given the high CAPE, which would be capable of producing damaging wind/wet microbursts. Soundings show substantial dry air entrainment with mid-level dry air to suggest some potential in a rare storm that grows tall enough for precipitation loading. PWAT will trend higher during the day and become increasingly sufficient for heavy rainfall rates, between the 75th and 90th climatological percentile when average values rise into the 1.5 and 1.7 inch range. For tomorrow night, an increasing pressure gradient and associated low level jet of southerly winds will prevent fog formation and lead to mild overnight conditions. Temperatures will be a few to several degrees milder than tonight, in the mid 60s to low 70s. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 249 PM EDT Friday...Sunday continues to look like a potential higher impact day for isolated severe weather and flooding, with signals for this event being more likely in northern New York than Vermont. We aren`t yet in the timeframe to see the full suite of convective allowing models, but generally the meteorological ingredients and limited CAM output suggests potential for more linear/widespread convection with this system, which would be oriented along a frontal boundary. Additionally, machine learning convective hazard forecasts show the northern Adirondacks having a local maximum for severe thunderstorm probability. While there are chances for thunderstorms Sunday afternoon/evening farther east, as we get closer to the event would not be surprised if PoPs get peeled back in eastern areas of the region; deep layer flow looks southwesterly/parallel to the incoming surface front, which will keep the eastward progress of showers and thunderstorms slow. Heat and humidity looks similar to Saturday, with perhaps slightly less heating due to more cloud cover. We also will see substantially more wind than recent days, with a large scale pattern where we will be squeezed between high pressure to our east and seasonably strong low pressure tracking well to the northwest near James Bay. Overnight the showers and thunderstorms should diminish in intensity somewhat as they progress eastward, while the surface front remains to our west through the night. Another mild night with southerly flow is expected aside from the showers and thunderstorms. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 217 PM EDT Friday...The slow-moving, stretched-out frontal boundary coming in Monday will continue to track eastwards. The better moisture plume from this coming Sunday will have shifted east. Although there`s another shortwave and moisture plume, various models disagree on the exact track of these secondary features. Some scenarios track these more along the coastline and are more ill- defined feature. Additionally, a warm layer aloft will suppress thunderstorm development. However, by midday, there should be enough instability to generate isolated to scattered shower and thunderstorm activity across Vermont. The clouds and overhead boundary will help conditions stay in the lower to mid 80s. Default ridging and largely zonal flow aloft will allow temperatures to trend higher again Tuesday and Wednesday with values flirting with 90 again. A few ensemble members are hinting at a decaying MCS type feature tracking across Canada that could just graze the region late next Wednesday into Thursday. It seems a few showers and storms could pop on the southern flank as it races east from James Bay toward Quebec City. The larger scale system will arrive towards next weekend with a deeper trough lifting northeast from the Great Lakes region. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Through 00Z Sunday...Main aviation concern over the next 24 hours will be patchy fog and low stratus that will develop over portions of the area. KBTV, KPBG, and KRUT will remain VFR over the next 24 hours with light terrain driven winds. Have included mention of fog or stratus at all other TAF sites, including KSLK, KEFK, KMPV, and KMSS. Main timeframe for development of low stratus and fog will be between 07Z and 11Z tonight, with improvement to widespread VFR conditions expected by 12Z. During the day Saturday, expect some isolated to scattered showers and thunderstorms to develop, especially over our southern counties. Chances are too low to include in this TAF package, which only goes out to 18Z Saturday, but chances ramp up beyond the 24 hour TAF period after 18Z Saturday. Outlook... Saturday Night: VFR. Slight chance SHRA, Slight chance TSRA. Sunday: VFR. Chance SHRA, Chance TSRA. Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA, Chance TSRA. Monday: Mainly VFR, with local IFR possible. Chance SHRA, Chance TSRA. Monday Night: Mainly VFR, with local MVFR possible. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Kutikoff NEAR TERM...Kutikoff SHORT TERM...Kutikoff LONG TERM...Haynes AVIATION...Duell