316
FXUS61 KBTV 310625
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
225 AM EDT Mon Aug 31 2026
.WHAT HAS CHANGED...
As of 223 AM EDT Monday...
Forecast for broader rains Monday evening into Tuesday continues to
trend southwards.
&&
.KEY MESSAGES...
As of 223 AM EDT Monday...
1. Dry today, and light shower activity possible on Tuesday.
2. A vigorous low will be capable of producing locally heavy
rain and thunderstorms on Wednesday into Wednesday night.
3. Trending drier into the weekend with a few chances for
lingering showers as an upper low departs to the east.
&&
.DISCUSSION...
As of 223 AM EDT Monday...
KEY MESSAGE 1: Widespread fog across Vermont and northern New York will
give way to supremely comfortable weather today. Patchy mid to high
level clouds will continue to stream along sluggish boundary to our
southwest. So the Northeast Kingdom should be nice and sunny, while
the North Country sees a bit more cloud cover. Temperatures will
rise into the 70s during the afternoon with light winds.
For this evening and overnight, the range of high res and global
models remain in better consensus of a southward position of
elevated convection along the aforementioned quasi-stationary front.
The high res guidance the last several days likely had some
convective feedback, and now that we`re closer, those models have
less time to get carried away. There should still be a swath of
moderate rain along the borderlines with our neighboring forecast
offices across Vermont and northern New York and little to no rain
across far northern Vermont. This also lowers the likelihood of
thunder. Pulled QPF back even further from the previous forecast.
About a third to half inch is likely in southern Rutland/Windsor
counties, and approaching the southern Adirondacks and far souther
St. Lawrence Counties, and just a couple hundredths at Vermont`s
international border. During the evening and overnight, a trough
will begin to develop while surface pressures rise along Coastal New
England. This appears like it will trap moisture along eastern
slopes. If forecast soundings weren`t too dry near the surface, I
would think this would be a drizzle/mist type set up. Flow aloft
remains somewhat fast, so perhaps there some forcing that produces
very light rain showers that linger into Tuesday night.
KEY MESSAGE 2: The more potent system appears to be the Wednesday
system. A trough tracking across the Northern Plains will eject east
as it gets caught between a closed upper low north of the Great
Lakes and an upper high in the southeastern US. Favorable conditions
for height falls will allow the development of a strengthening
surface low across the Great Lakes quickly moving east by Wednesday
afternoon. Initially, we`ll still have high pressure in the Canadian
Maritimes holding dry stable air east and west-northwest flow aloft
still maintaining the line between this dry air and warm, moist air
to our south. As the surface low develops a warm front will shift
east late morning into the early afternoon. Light rain should push
west to east, but any rain from it will be tempered by the low-level
dry air. That warm front will shift just north of the international
border, and then the surface low will follow Wednesday night.
Increasing instability (mostly aloft) and sharp frontogenetic
forcing against stubborn high pressure will produce thunderstorms
that will be capable of heavy rainfall. The degree of elevated
instability remains in question, and there will almost certainly
still be some wobbles in the exact track as we`ve seen for Tuesday`s
system depending on convective processes and where exactly low
pressure will track along a still present sluggish thermal/moisture
gradient.
KEY MESSAGE 3: Our Wed/Thu system will occlude Thursday night off the
southeast New England Coast, dragging its parent low southeast with
it. Showers look to continue as wrap around moisture lingers across
Vermont, with some drying in northern New York. The upper low will
drift over northern Maine by Friday keeping cyclonic flow
northeasterly flow entrenched. While most of the late week and
weekend looks to be on the drier side, isolated to scattered
diurnally driven showers during the day will be possible, mainly
over eastern Vermont and the Adirondacks. Current precipitation
chances are around 35-50%, with the exception of the higher terrain
which currently have PoPs to 60-70%. Any daytime shower activity
will wane by the evenings. Skies look to remain on the cloudy side
Friday into Saturday. Friday looks to be the best chances for rain
in the late week and weekend with rain chances decrease each day
towards next week. Temperatures will generally be seasonable in the
60s and 70s, but there is a chance for some lower temperatures than
current guidance is suggesting across eastern Vermont should more
clouds, and precipitation develop. Overnight lows will trend cooler
into the weekend towards the mid 40s to low 50s as subtle ridging
and some radiational cooling nights are to be expected heading into
next week.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday...A moisture gradient is becoming washed
out in a line from Lebanon, NH to Massena, NY. To the northeast,
widespread dense fog has formed at EFK, with vicinity fog noted
at PBG, and already ongoing fog at FSO as well in the northern
Champlain Valley. Satellite shows this fog seeping south and
west towards MPV/BTV. Into NY, fog is also already evident at
MSS/SLK, with some bouncing at SLK due to due some slight mixing
aloft as the moisture gradient is centered over the terminal.
There is medium to high confidence for fog at all terminals,
outside of RUT. RUT may stay fog free tonight as they are on the
south side of the gradient and may hold onto a very light
drainage wind. Have used TEMPO grids for IFR at sites not
already entrenched in fog (PBG/BTV/MPV). Highest confidence in
prevailing fog at most sites will be from 08-12Z. Prevailing fog
at BTV/PBG may be delayed until closer to 09-10Z, with bouncing
IFR beginning around 08Z, though there is lower confidence that
fog may move in for BTV as early as 07Z, though did not get
this aggressive in this forecast. Conditions look to improve
back towards VFR in the 13-14Z period, outside of PBG/BTV, where
improvements will be slightly earlier between 12-13Z should fog
develop. Quiet VFR aviation conditions are expected after 14Z
through 00Z with mainly clear skies, and light and variable
terrain driven winds. Clouds back build in after 00Z tonight.
Outlook...
Tuesday: Mainly VFR, with local MVFR possible. Likely SHRA,
Slight chance TSRA.
Tuesday Night: Mainly MVFR, with local IFR possible. Chance SHRA.
Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA,
Slight chance TSRA.
Wednesday Night: Mainly MVFR, with local IFR possible. Chance
SHRA, Slight chance TSRA.
Thursday: Mainly MVFR, with local IFR possible. Chance SHRA.
Thursday Night: Mainly MVFR, with local IFR possible. Chance
SHRA.
Friday: MVFR/IFR conditions possible. Chance SHRA, Slight chance
TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Haynes
DISCUSSION...Danzig/Haynes
AVIATION...Danzig
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