-- Discussion containing changed information from previous version are highlighted. --
944
FXUS61 KBTV 211724
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
124 PM EDT Fri Jun 21 2024

.SYNOPSIS...
Unsettled weather will continue through the weekend as a frontal
boundary wavering over the region will result in repeated rounds of
showers and thunderstorms. Temperatures will be much more seasonable
through the weekend, as well, with highs generally in the 70s and
80s.

&&

.NEAR TERM /THROUGH SATURDAY/...
-- Changed Discussion --
As of 112 PM EDT Friday...Adjusted precipitation chances
slightly over the next few hours as showers spark up across the
forecast area this afternoon. Temperatures are catching up to
previously forecast levels, so no real changes there. Previous
discussion below:

Previous discussion...Showers have come to an end early this
morning and the frontal boundary now lies draped over southern
sections of our forecast area. The front will settle just to our
south during the daylight hours, bringing much needed relief from
our recent heat wave. However, do expect scattered to numerous
showers and thunderstorms to develop along the front this afternoon,
mainly along and south of a line from Tupper Lake NY to Corinth VT.
Severe weather is not anticipated, though thunderstorms will be
capable of producing locally heavy rainfall and perhaps some gusty
winds, especially over southern Rutland/Windsor Counties. Highs will
range from the mid/upper 70s to the lower 80s.

Showers and thunderstorms will wind down this evening as we lose
daytime heating, though ample low-level moisture will allow patchy
fog to develop again overnight. Lows will be much more comfortable
than what we`ve seen recently, generally in the upper 50s to mid
60s.

Precipitation chances then return for Saturday as the front lifts
back north as a warm front. A weak wave of low pressure will slide
along the front late Saturday, helping to turn flow back toward the
south/southwest and ushering deep moisture northward. PWATs of 2.0
inches will return by the afternoon, and instability returns as CAPE
values approach/exceed 1500 J/kg. Hence expect thunderstorms will be
possible, especially over the central and southern Adirondacks and
south-central VT. 0-6km shear will be somewhat favorable at around
30 kt, so some stronger storms capable of producing gusty winds
can`t be ruled out. The bigger threat however will be heavy
rainfall. Note that the latest Day 2 Convective Outlook from SPC
keeps the Marginal Risk just to our south, while the Day 2 Excessive
Rainfall Outlook from WPC includes our entire forecast area in a
Marginal Risk. Anyone with outdoor plans should stay tuned to
forecast updates and be aware of any increasing threats. Highs on
Saturday will be in the low 70s to low 80s.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
As of 330 AM EDT Friday...An area of low pressure will pass through
the North Country on Sunday, bringing a potential flooding and
severe threat. A stalled frontal boundary will be draped across the
region Saturday night into Sunday before the center of the low
passes through. Along it, there will be strong frontogenetic forcing
and a favorable environment for heavy precipitation. PWATs will
range between 1.5 to 2 inches and there will be a very deep warm
cloud layer to about 12- 13K FT. This boundary will be mostly
stationary, so where it sets up there will be heavy rainfall and
likely some localized flooding. Right now, the GFS/Euro ensemble
guidance favors it setting up over southern Quebec, just over the
international border, but the placement has been moving slightly
back in forth with each model run. Looking at the deterministic
guidance, there will likely be a narrow area of 2-3+ inches of rain
with this feature. The WPC ERO highlights the northern part of the
region in a slight risk which seems reasonable for now, but if
confidence increases that the band will set up north of the region,
that will likely need to get removed. South of this front will be
able to briefly reach the warm sector of the storm. That looks to
cause some marginal instability to develop, at least over southern
Vermont, where there is higher confidence that the front will be to
the north. Euro/GFS ensembles give southern Vermont around a 40-60
percent chance of seeing higher than 500 J/Kg of CAPE, lowering to
close to 0 near the international border. With adequate deep layer
shear, there is a severe threat, but with the limited CAPE, it
should be on the low end. The cold front will come through late in
the day on Sunday and bring the highest chance of severe storms.
Behind the front, temperatures and dew points will gradually drop a
little.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
As of 330 AM EDT Friday...Behind the front, the weather pattern
remains active. An upper level low moves over the region on Monday.
With cold temperatures aloft, diurnal heating will cause some low-
topped convection to develop in the afternoon. However, the severe
threat with these should be limited. Brief ridging looks to build in
on Tuesday and temperatures look to warm back above normal. A
stronger cold front comes through on Wednesday and should finally
bring some more refreshing air into the region for the end of the
week. There is the potential for severe weather with this frontal
passage, but that would depend on the timing of the passage and how
much instability will be able to develop ahead if it.

&&

.AVIATION /17Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
Through 18Z Saturday...Scattered showers are developing across
the forecast area this afternoon, so VCSH is plentiful within
the TAFs. Watching RUT closely at this time as thunderstorms may
approach. Outside of showers and thunderstorms occasionally
lowering cigs and restricting vis, VFR is expected for all sites
through about 04Z-12Z Saturday, which is when fog/mist is
expected to develop, with highest confidence at SLK, MPV, and
RUT. Fog will likely last about 06-12Z, then low ceilings will
prevail at most if not all sites early tomorrow. We are
anticipating more widespread showers and thunderstorms for
tomorrow as a frontal boundary lifts north, which could keep
conditions soupy with low ceilings and visibilities. Winds
throughout the next 24 hours will be largely light and variable
to calm outside of thunderstorms.

Outlook...

Saturday Night: Mainly VFR, with local IFR possible. Likely SHRA.
Sunday: Mainly MVFR, with local IFR possible. Definite SHRA,
Chance TSRA.
Sunday Night: Mainly MVFR, with areas VFR possible. Likely SHRA,
Slight chance TSRA.
Monday: Mainly VFR, with areas MVFR possible. Likely SHRA, Slight
chance TSRA.
Monday Night: Mainly MVFR, with areas VFR possible. Chance SHRA,
Slight chance TSRA.
Tuesday: VFR. Slight chance SHRA.
Tuesday Night: VFR. Slight chance SHRA.
Wednesday: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance TSRA.
-- End Changed Discussion --

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Hastings
NEAR TERM...Hastings/Storm
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Storm