-- Discussion containing changed information from previous version are highlighted. --
306
FXUS61 KBTV 231143
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
743 AM EDT Sun Jun 23 2024

.SYNOPSIS...
Strong to severe thunderstorms are expected this afternoon into the
evening. The greatest threats are damaging winds and hail, but there
is also the possibility of an isolated tornado. Heavy rainfall could
lead to localized flash flooding in areas that receive multiple
storms. Quieter but still unsettled weather continues into the start
of the work week.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 631 AM EDT Sunday...An area of heavy rain is currently
over the region and it will push to the east and out of the
region by mid-morning. There are a few embedded thunderstorms
but they are mostly along the southern edge of this area of
rain. They will generally pass through the southern zones though
an isolated thunderstorm cannot be ruled out anywhere. None of
these storms will be severe though. After the rain moves out,
the key question is how fast the surface warm front can move
through and how quickly the clouds move out on the backside. The
clearing has reached the Mohawk Valley and is currently
beginning to make its way through the Southern Adirondacks and
Tug Hill Plateau.

Previous Discussion...A warm front is currently pushing north
across the region. It is bringing an an area of heavy showers
with a couple embedded thunderstorms into northern New York.
These will push into Vermont later tonight and should mostly
exit the region by mid- morning. The instability is elevated so
none of the storms here should be severe. There is also less
instability here than in areas to the south so any strong storms
there should weaken a bit before they move in. After the
showers move out, clouds will scour out as the warm front passes
to the north tomorrow morning. However, it could take until the
afternoon for that to occur east of the Greens. These lingering
clouds may keep the instability a little lower today, but even
if that occurs, a significant severe day still looks likely.
With strong surface warm air advection, it would not take long
for the atmosphere to destabilize once the sun comes out.

Conditions today will favor severe winds and hail, but a few
isolated tornadoes are possible as well. Using HREF averages, 0-6 KM
shear will be between 30-40 KTs and 0-1KM SRH will be between 100-
200 m2/s2. The possible limiting value will be CAPE. Between 1000-
1500 J/Kg is expected to develop this afternoon, but that is
dependent on how long the cloud cover can last. If the clouds linger
into the afternoon, these values will likely be lower, though it
given the rest of the environment, it would not take much CAPE for
some severe thunderstorms to develop. DCAPE should be between 500-
700 J/Kg so there is the possibility of a microburst, but it is not
the most favorable environment for that to occur. High PWATs and warm
cloud depths will allow for a flash flooding threat, but fast storm
motion would probably require multiple storms hitting the same area
for isolated flash flooding to develop. A strong cold front will
provide adequate synoptic lift. The storms will develop in the
afternoon and continue into the evening. It currently looks like
there will be a few isolated supercells, but most of the convection
looks to be quasi-linear. The severe threat tapers off later in the
evening.

An upper level low builds in for Monday, and the cold air aloft will
cause low topped convection to develop from diurnal heating. An
isolated thunderstorm is possible but it would not be severe.
Temperatures will on the cooler side of normal, with highs in the
60s and 70s. Dew points will eventually drop into the 50s so it will
feel more refreshing.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 359 AM EDT Sunday...Showers will briefly linger over mainly
eastern Vermont, but these will quickly come to an end as the upper
trough exits and drier air spreads into the region. Tuesday will see
plenty of sunshine with no precipitation expected. Highs will reach
into the lower to mid 80s. Monday night`s lows will be in the upper
40s to upper 50s, but Tuesday night will be a good 5-10 degrees
warmer as flow starts to shift to the southwest ahead of an
approaching cold front. Scattered showers with a few embedded
thunderstorms will spread across much of the region late Tuesday
night/early Wednesday morning, but the bulk of the activity
associated with the cold front will hold off until after daybreak.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 359 AM EDT Sunday...Wednesday will be the most active of the
period as moisture streams back northward ahead of a cold front
moving in from the west. While model soundings continue to indicate
a potential capping warm layer around 800 mb, still expect showers
and thunderstorms to develop ahead of the front and/or along a pre-
frontal trough. SB CAPE values are progged to reach 500-1200 J/kg,
and with 0-6km shear of 30-40kt, strong to severe thunderstorms
would possible. We`ll continue to monitor trends as this system gets
closer.

The cold front moves through by Wednesday night, ushering in a drier
airmass. High pressure will settle over the region, bringing a
couple of dry, pleasant days with seasonable highs in the 70s to
around 80F and lows in the 40s and 50s. Our next chance of rain will
move in on Saturday with another frontal system lifting across the
region.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Through 12Z Monday...A slow-moving warm front will push north
of the region this morning, bringing showers and low ceilings.
Low ceilings will continue until the front passes to the north
and strong southerly flow scours out the low-level clouds. This
has occurred at the New York terminals and BTV/RUT already. This
will occur at the rest of the terminals this morning. During
the day today, ceilings at all terminals will rise to VFR.
Showers will exit the region by mid-morning but a few of them
could be heavy enough to briefly lower visibilities to MVFR and
IFR. Winds will be very light before becoming strong out of the
south during the day, with gusts over 20KTs possible at any
terminal. Scattered to numerous thunderstorms will develop this
afternoon and evening, some of which will contain damaging winds
and large hail. Whether any of these storms hit a specific
terminal is uncertain because of their scattered nature, but
they are possible anywhere. These will also be able to briefly
lower visibilities to MVFR and IFR. LLWS will continue this
morning before weakening a bit this afternoon.

Outlook...

Monday: Mainly MVFR, with local IFR possible. Chance SHRA, Slight
chance TSRA.
Monday Night: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Tuesday: VFR. NO SIG WX.
Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Wednesday: VFR. Likely SHRA, Chance TSRA.
Wednesday Night: Mainly VFR, with areas IFR possible. Chance
SHRA, Chance TSRA.
Thursday: Mainly MVFR, with areas VFR possible. Slight chance
SHRA.
-- End Changed Discussion --

&&

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

&&

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