272
FXUS61 KBTV 070224
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1024 PM EDT Sat Jul 6 2024

.SYNOPSIS...
Mostly dry weather will start off the week, though an isolated
shower is possible tomorrow. The heat and humidity will remain
in place as well. A cold front will approach from the west,
bringing a renewed threat of showers and thunderstorms late
Tuesday into Wednesday. Some of the stronger thunderstorms
could produce locally heavy rainfall.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 1017 PM EDT Saturday...Lessening surface-based instability
late this evening will continue to allow showers and a few
embedded thunderstorms to wane. At 02Z, remaining showers are
across far nern VT and along the international border from near
Jay to Highgate. Most of this activity should diminish and/or
exit to the east of the region by 04-05Z. Rainfall earlier this
evening was locally heavy, with rainfall totals of 1-2" across
portions of Addison and Washington counties where convective
storms were the most widespread and frequent. Included in this
was the KMPV airport, with 1.88" today which appears to be a
calendar day record (1.28" on 7/6/1948).

As clouds decrease, main story after midnight will be locally
dense fog. Dewpoints remain near 70F and main sections of the
North Country experienced a wetting rainfall during the past
12-18 hrs. As such, should see areas of dense fog developing
near or just past midnight, and fog may possibly be widespread
across central and eastern VT. With light and variable winds,
little overall change in the muggy conditions overnight with
dewpoints remaining in the upper 60s to lower 70s in most
locations.

Drier weather returns for Sunday but there will be a weak
shortwave trough passing to the north of the region and that
could set off a shower or two across northern areas. The heat
will continue for Sunday with highs in the 80s again, but dew
points will drop off slightly into the 60s. Patchy fog looks to
develop Sunday night as well, mainly during the 06-12Z time
frame.

&&

.SHORT TERM /MONDAY NIGHT/...
As of 532 PM EDT Saturday...Surface high pressure moves overhead on
Monday, and recent cold front passage (Sat) brings in drier air at
the surface and aloft, thus it should be sunny and very warm again.
Decent surface heating should mix drier air to the surface thus it
should be very warm but dry. Highs in the M80s-L90s.

Surface high shifting east Monday night allowing return flow to
bring an increase in moisture at all levels that have been plaguing
the Tristate and Mid-Atlantic for some time, thus increasing
dewpoints with lows in the 60s to around 70.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 532 PM EDT Saturday...Bermuda High offshore and northern stream
disturbance moving across the Great Lakes on Tuesday will continue
the SSW warm and increasingly humid airmass into our region.
Ensemble PWATs show 1.5- 1.75 inches across our area with 1.75-2
inches across SNE and Hudson Vly southward with over 2 inches from
NYC southward. Deterministic models have higher values and advect
some of these higher PWATS just ahead of approving northern stream
system.

There is some higher level moisture from Beryl getting entrained
along the approaching frontal boundary, but the main moisture source
is locally grown with PWATS greater than 90th percentile across our
area with rising warm cloud depth layers for likely efficient rain
producing showers and thunderstorms. The big question is how much
activity, timing and is there more than one round?

Unfortunately, the picture isn`t very clear but the general
consensus is daytime heating, instability and likely position of a
pre-frontal trof across NY will be a focus of shower/t-storms with
mid-level energy moving across the area as well. The mid-low level
flow appears nearly parallel to the boundary thus likely looking at
potential training showers/t-storms while the mid-level trof
continues to lift ENE for the boundary to slowly push across NY-VT
late Tuesday-Tuesday night and perhaps be east of area by Wed AM.

At this time...a general 1/2-1 inch with localized training of 2+
inches not out of the question.

WPC has the area in Marginal risk attm and feel that is justified.

Still under somewhat cyclonic flow on Wednesday with PWATS still
1.25 and higher and another weak shortwave and secondary cold front
pushing through for another round of showers and possible
thunder...esp southern areas.

While all of this is happening, the upper level Bermuda High is
strengthening thus the second frontal boundary that passes Wed is
never too far away and lies across eastern and southern New England
so can`t rule out shower threat, mainly south on Thursday while high
pressure tries to make progress across the northern tier.

As we get into Thu Ngt-Friday...the mid-level energy of what was
Beryl gets lifted and captured into the general trofiness across the
Great Lakes and Ms Rvr Vly. The weak surface reflection moves into
the Ms Rvr Vly and Ohio Rvr Vly and then eventually across the
northeast as a possible weak surface wave.

Meanwhile, the strengthening Bermuda High begins to push the
previous cold front as a warm front with the main story being rich
moisture (PWATS 1.75-2+ inches) across SNE and mid-Atlantic
advecting back towards our area.

Will these two identities move across the area separate or will
they interact for more organized rounds of rain and heavy rain
showers. Still too early but worth to monitor closely. At the
very least it looks showery and wet for Friday and Saturday.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Through 00Z Monday...VFR prevails this Saturday evening,
interrupted by brief heavy showers reducing visibilities as low
as a half mile for some. These showers will continue for the
next few hours and end by 06Z Sunday, replaced by drier weather
and clearing skies by 06Z and onward. With light winds, high
dewpoints/crossover temperatures, and recent rainfall, fog is
expected to develop, especially across Vermont where wind will
be the lightest. Most likely sites for IFR conditions will be
SLK, EFK, and MPV from 05Z-13Z Sunday, though fog is not out of
the question at any site tonight, especially those that had rain
today. Following the fog, tomorrow will be a dry, VFR day with
winds under 10 knots out of the southwest.

Outlook...

Sunday Night: VFR. Patchy BR.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Chance SHRA, Chance TSRA.
Tuesday Night: VFR. Likely SHRA, Likely TSRA.
Wednesday: Mainly VFR, with local MVFR possible. Chance SHRA,
Chance TSRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.
Thursday: Mainly VFR, with local MVFR possible. Chance SHRA.

&&

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

&&

$$
SYNOPSIS...Myskowski
NEAR TERM...Banacos/Myskowski
SHORT TERM...SLW
LONG TERM...SLW
AVIATION...Storm