817
FXUS61 KBTV 062334
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
734 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 on Wednesday and
bring some showers and storms. Some of these could produce
locally heavy rainfall.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
As of 532 PM EDT Saturday...A few areas of convection have developed
this afternoon, and scattered showers will continue for the rest of
the day. The most numerous showers are along a very weak nearly-
stationary boundary located across central Vermont. However, it has
been moving just quick enough to prevent repeated training storms.
With 1-1.5 inches of rain falling across parts of the region this
morning, there are a few areas vulnerable to localized flash
flooding. However, there would likely need to be multiple training
storms, and that has not been occurring. Storm motion should
continue to be faster, so that is unlikely to occur during the rest
of the day. Model soundings show a subtle mid-level inversion at
around 20-25K feet, corresponding to around the -10 to -20 degrees
celsius level. That has been able to top the convection and prevent
much lightning from occurring. Continued daytime heating looks to
allow the convection to reach a little higher and that could lead to
a few more storms with lightning, but overall most of the convection
should not contain lightning. The convection will die down this
evening and skies should at least partially clear. With light winds,
high dewpoints/crossover temperatures and recent rainfall, fog will
develop, especially across Vermont where wind will be the lightest.
Drier weather returns for Monday but there will be a weak shortwave
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.

&&

.SHORT TERM /MONDAY THROUGH 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 SATURDAY/...
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 /00Z 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...Myskowski
SHORT TERM...SLW
LONG TERM...SLW
AVIATION...Storm