806
FXUS61 KBTV 202359
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
759 PM EDT Thu Jun 20 2024

.SYNOPSIS...
Our hot streak will come to an end with temperatures returning
to seasonable levels to end out the week. Additional
thunderstorm chances are expected over the weekend with the best
chances occurring Sunday.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 751 PM EDT Thursday...Showers and thunderstorms are
continuing, but are no longer severe. Shower activity will die
down overnight. Some fog formation is expected as winds become
light with lots of low level moisture in place. Minimum
temperatures will dip into the 60s areawide tonight, some
welcome relief from the past couple nights. Previous discussion
follows.

High pressure located in the Atlantic Ocean continues to draw
warm, moist air into the forecast area from the west/southwest
this afternoon and evening, and mid level westerly winds will be
strongest across the international border where deep layer
shear is most significant. A cold frontal boundary will be
dropping through this evening from north to south, continuing to
trigger showers and thunderstorms as well as putting an end to
our three day heat wave. As the front clashes with our warm,
humid air mass in place, this will be the focus of convection
this evening. Deep layer shear as a whole is meager, but
precipitable water values are impressive, up to around 2 inches
in some spots. Modeled MLCAPE values are 2000-3000 J/kg. The
main concern with these storms will be damaging wind gusts and
hail, which has already been reported across portions of the
forecast area this afternoon. In addition to severe concerns, we
are also monitoring the thunderstorms for heavy rain over the
same area, as this could result in isolated flash flooding. The
storms are expected to be slow moving along the stalling front,
which would allow a heavy storm to drop an impressive amount of
rain in one spot before moving on under high pwat conditions.
Expected rainfall amounts will vary depending on where
thunderstorms occur, but generally thinking 0.20-1.00".
Thunderstorm threat should end around 8 PM this evening as we
lose daytime heating and instability.

Low temperatures will fall into the 60s for most tonight, which
will be much cooler than it has been the last few nights, but
still a good 5-10 degrees above average. Thick moisture at the
surface will result in patchy fog in the classic valley
locations and those that received plenty of rain from the
showers and storms today. Tomorrow will be cooler than today,
returning our highs back to around seasonable levels in the
upper 70s to mid 80s. Showers and thunderstorms are expected to
return tomorrow, mainly for the southern half of the forecast
area along the frontal boundary. Severe weather is not
anticipated tomorrow. Rainfall amounts should be up to a half an
inch. Tomorrow night, this frontal boundary will be stalled out
just to our south, which again will be where most showers set
up. Lows will fall even farther tomorrow night into the mid 50s
to mid 60s, still about 5 degrees above climatological normals.
Once again, there is the potential for some fog with the
stationary boundary and low level moisture.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 410 PM EDT Thursday...Active weather with showers and
thunderstorms continues on Saturday, with potential impacts more
towards excessive rainfall than strong thunderstorms with
limited instability. Temperatures have trended a bit cooler for
Saturday associated with northerly low level flow, clouds, and
showers. Highs may be only in the upper 60s to low 70s in much
of northern New York and Vermont. However, south of a surface
front a chance of thunderstorms is indicated. In this region,
which may include much of south central Vermont into portions of
the Adirondacks, daytime heating and moist boundary layer air
would support tall skinny CAPE that could result some showers
that can produce frequent lightning along with torrential rain.
However, even showers on the cool side of the front will be
capable of torrential rain with high precipitable water, deep
cloud layer depths in a very moist air mass. Given suddenly
wetter antecedent conditions, potential for flash flooding may
be elevated. The orientation of the front, largely draped west
to east, will likely act as a focus for additional showers and
thunderstorms back across the eastern Great Lakes Saturday night
while the front bulges northward in our region. As such,
despite relatively cool air on Saturday, it may not cool off
much overnight.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 410 PM EDT Thursday...Sunday is set up to be potentially
a significant severe weather day as a strong cold front
approaches from the west. Most model guidance brings upper level
support through our region during the afternoon hours
coincident with an unseasonably strong surface low lifting
through the St. Lawrence Valley, putting our region in the
system`s warm sector. Amongst the global model clusters, three
of the four scenarios for Sunday produce ingredients for severe
weather Sunday afternoon, which would include organized
thunderstorms given the deep layer shear and moderately high
CAPE expected. The one scenario that does not suggest an active
day, driven by many GEFS members, shows very little instability
due to a lot more ongoing showers. Mid level flow looks to be
southwesterly near 40 knots at 700 millibars, with increases in
upper level winds coinciding with peak heating as heights fall.

After this cold front crosses the region, humidity should trend
downward to more comfortable conditions on Monday. The next
opportunity for severe weather then may follow for Wednesday as
another strong cold front may pass through the region. Below
normal temperatures finally may arrive for Thursday following
that frontal passage.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...Showers and thunderstorms are dying down
in strength, but will continue for another couple hours.
Another round of fog after 06z Friday, especially in areas that
see rain. Have gone with IFR conditions at KMPV/KSLK, with some
MVFR mentions at other stations. All stations should return to
VFR after 13Z on Friday. Some scattered showers will be possible
again Friday afternoon, especially south.

Outlook...

Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance TSRA, Patchy BR.
Saturday: Mainly MVFR, with areas VFR possible. Chance SHRA,
Slight chance TSRA.
Saturday Night: Mainly MVFR, with local IFR possible. Chance
SHRA, Slight chance TSRA.
Sunday: Mainly MVFR, with local IFR possible. Definite SHRA,
Chance TSRA.
Sunday Night: Mainly MVFR, with local IFR possible. Chance SHRA,
Slight chance TSRA.
Monday: Mainly MVFR, with areas VFR possible. Likely SHRA, Slight
chance TSRA.
Monday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Tuesday: VFR. NO SIG WX.

&&

.EQUIPMENT...
Our radar KCXX is currently down. Time of return is unknown at
the moment.

&&

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

&&

$$
SYNOPSIS...Storm
NEAR TERM...Neiles/Storm
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Neiles
EQUIPMENT...Team BTV