857
FXUS61 KBTV 040517
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
117 AM EDT Tue Jun 4 2024

.SYNOPSIS...
Increasing moisture is expected. Isolated showers, coverage more
scattered over high terrain, will begin to develop with a few
rumbles of thunder. The weather pattern will begin to shift over the
later part of the week as an upper low approaches from the west.
This will bring cooler temperatures from 80s back to mid 70s and
lower 80s. The upper low will also bring more widespread rain
chances across the region.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 111 AM EDT Tuesday...Did lower temps at SLK as they are
already near anticipated low for the night as of 1 AM, otherwise
fcst in good shape. Expecting lows to range from lower 40s
NEK/SLK to near 60F in the Champlain Valley with mostly clear
skies and light trrn driven winds.

PREVIOUS DISCUSSION...

Temperatures are running about 10 degrees above normal this
afternoon under very dry, subsident air beneath a broad upper
ridge. Outside some terrain driven cumulus, it`s mostly clear.
For tonight, dry conditions are expected, but radiational
cooling doesn`t appear as strong with slowly increasing
moisture. Cool hollows will likely still fall into the 40s, but
most locations should stay in the 50s with perhaps a few spot
readings of 60 in the Champlain Valley.

For tomorrow, 925 hPa temperatures are about a degree or two warmer,
and so the forecast is for max temperatures to creep just a bit
higher. BTV and MSS are forecast to reach 88 at present. Ensemble
forecasts are about 10 to 30 percent chance of reaching 90. So it`s
not out of the realm of possibility. In eastern Vermont, it appears
there could be a backdoor cold front that slides into the area,
which will be reinforced by a developing sea breeze, and that could
help keep temperatures somewhat cooler in far eastern Vermont. With
a bit more moisture on the ground, greater heating, and the presence
of a subtle boundary in eastern Vermont, there should be enough
forcing to break a capping inversion, at least across the mountain
ranges. Since there`s still plenty of dry air underneath the
upper ridge still in place with little to no shear present, only
garden variety showers are anticipated across the Adirondacks
and eastern Vermont. A rumble of thunder would be most likely in
the Dacks. Overnight, a subtle theta e ridge axis will shift
east in conjunction with the development of a weak surface
trough and tiny embedded upper trough. It`s not much, but it
appears to be enough with 300 to 500 J/kg of elevated CAPE that
high resolution guidance is developing hit-or-miss showers in
the Champlain Valley. The HREF paintball briefly shows several
members with this type of development. So have refined the
forecast to highlight some of those details with a 20 to 30 PoP
in and around the Champlain Valley overnight. Not anticipating
the activity will be strong enough for thunder at the moment.
Increasing south flow and additional moisture will result in a
humid conditions Tuesday night into early Wednesday with mid
50s to mid 60s.

&&

.SHORT TERM /WEDNESDAY NIGHT/...
As of 300 PM EDT Monday...Wednesday will be another warm day
with highs reaching the mid to upper 80s. The humidity will also
be higher as dew points will be in the low 60s. Diurnal heating
will cause some instability to develop, but with minimal flow
aloft, it will be mostly terrain driven pulse-type thunderstorms.
Scattered showers and storms will likely develop in the
mountains during the early afternoon and may spread a bit into
the broad valleys later in the afternoon, but the coverage will
be more isolated there. Some guidance is suggesting up to 1500
J/KG of CAPE will be in place but with limited shear, there is
no severe threat with these storms. The showers will decrease in
coverage overnight without the diurnal heating but a cold front
will reach northern New York and cause some shower chances
there to increase there later in the night. With the increased
humidity and some lingering clouds, lows will only fall into the
60s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 300 PM EDT Monday...An unsettled pattern will be in place
during much of this period as a closed off low will be lingering for
several days. An initial cold front will come through Thursday into
Thursday night and bring some steadier rain. There is still high
model uncertainty with the exact timing of the front and how much
moisture it will be able to bring up into the area, but there is
good consensus that the front will be through by Friday morning.
However, there is no real consensus on QPF. Looking at a Euro, GEFS
and Canadian ensemble mixture, there is a roughly a 25 percent
chance that the region sees over an inch of rain while there is
around a 50 percent chance that the region sees under a half inch.
With model guidance trending toward slightly less precipitation,
conservatively went with around 0.25-0.50 inches for the region.
Areas that see heavier convective showers will see locally more. The
WPC put the region in a marginal risk ERO for flash flooding but
with dry antecedent conditions, that would likely require the higher
end synoptic-driven rain totals and training storms to occur in the
areas that see the most synoptic-driven rain. Therefore, flooding
looks unlikely at this time. After the front moves through, an upper
level low will be situated over the region and bring some shower
chances every day. There will be some embedded shortwaves that pivot
around it that will increase shower coverage during a few periods.
Temperatures will also drop back to or slightly below average with
the cooler airmass and increased clouds and showers. The shower
chances look to continue to the middle of next week at the moment.

&&

.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
Through 06Z Wednesday...Surface high pressure is providing our
taf sites with mostly clear skies and light winds this morning.
Have noted the AvnFPS ceiling/vis climo trend tool is indicating
a non zero potential for IFR or lower in br/fog at SLK btwn
08-10z this morning with probabilities of 20-25% based on crnt
obs. Have placed VCFG at 08Z and may place last minute tempo
group for br btwn 08-10z to cover potential. Otherwise, VFR
conditions prevail at rest of the sites for the next 12 to 24
hours with some isolated showers possible this aftn btwn
20z-24z. Light trrn driven winds will result in southeast winds
at RUT/PBG and northeast at MSS with light and variable under 5
knots elsewhere.

Outlook...

Wednesday: VFR. Scattered SHRA, Scattered TSRA.
Wednesday Night: VFR. Chance SHRA, Slight chance TSRA.
Thursday: MVFR/IFR conditions possible. Likely SHRA, Slight
chance TSRA.
Thursday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, Slight chance TSRA.
Friday: Mainly VFR, with local MVFR possible. Likely SHRA, Slight
chance TSRA.
Friday Night: Mainly VFR, with local IFR possible. Chance SHRA.
Saturday: Mainly VFR, with areas MVFR possible. Likely SHRA,
Slight chance TSRA.

&&

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

&&

$$
SYNOPSIS...Haynes
NEAR TERM...Haynes/Taber
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Taber