-- Discussion containing changed information from previous version are highlighted. --
262
FXUS61 KBTV 210531
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
131 AM EDT Tue May 21 2024

.SYNOPSIS...
A quiet and mild night is expected across the North Country with
temperatures falling back into the mid 50s to lower 60s. A few
showers are possible across northern New York toward sunrise, but
addition scattered showers and thunderstorms are anticipated on
Tuesday afternoon and evening. A few stronger storms will be
capability of small hail, gusty winds, and frequent lightning.
Temperatures warm well into the 80s on Tuesday with even warmer
temperatures on Wednesday before cooler air arrives for late week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 128 AM EDT Tuesday...Temperatures have been steadily
dropping overnight but continuing boundary layer winds are
helping keep the Champlain Valley mixed. This is keeping
temperatures there warmer than forecast and had to raise them a
little. Temperatures will generally stay above the crossovers so
fog development should be limited compared to previous nights.
ANy fog that develops will likely be in eastern Vermont.
Convection that formed north of Lake Ontario quickly decayed
before reaching the region so tonight should remain dry. Any
subsequent convection should not arrive until well after
daybreak. Previous discussion follows...

Mid/upper lvl ridge is located over the Mid-Atlantic States,
while westerly flow aloft prevails acrs our cwa. Some shallow
instability driven cumulus clouds have developed over the trrn,
but given the lack of forcing and deep layer moisture, just an
isolated shower is possible. Overall, a quiet and mild night is
anticipated with temps slowly cooling back into the mid 50s to
mid 60s. Have noted a complex of storms developing near Detroit,
MI into the northern Ohio Valley, while is tracking to impact
our western NY cwa btwn roughly 10z-14z Tues. This is associated
with secondary warm frnt type feature and have placed low chc
pops to cover the potential for showers and a few rumbles of
thunder.

Tues/Tues night, expecting a fairly active period of wx with
scattered showers/thunderstorms and a few stronger to locally severe
storms possible. SPC Day 2 Outlook continues with marginal risk for
severe, which looks reasonable when examining sounding and pre-
environmental conditions. Synoptic scale pattern shows weak embedded
convectively induced 700-500mb s/w energy traveling along northern
periphery of mid/upper lvl ridge impacting our cwa btwn 18z-00z
Tues. This energy wl be associated with a ribbon of enhanced 700mb
winds of 30 to 40 knots and modest height falls.

Pre-storm environmental parameters suggest a pulse type convective
mode, with maybe a few embedded bowing segments, but organized
convective wl be limited given the unidirectional wind profiles,
weak forcing, and 0 to 6 km shear values near 30 knots. Sfc based
CAPE values should increase to 1500-2000 J/kg, supported by highs
well into the 80s and sfc dwpts in the lower/mid 60s, which should
be reachable with MSS already 63F this aftn. Sounding data shows
steep 0 to 3 km lapse rates and DCAPE values near 1000 J/kg,
supporting the idea of localized gusty thunderstorm winds associated
with the stronger convective elements. In addition, given the EL
near 200mb and rather large CAPE profiles, the stronger updrafts
cores wl be capable of some very localized near severe hail. Have
gone ahead and placed marginal severe wording for small hail, gusty
winds, and heavy rainfall in fcst btwn 18z-00z Tues. Given the
potential vertical development of convection and pw values btwn 1.20
and 1.40, localized heavy down pours wl be possible, but potential
for flash flooding is minimal given anticipated storm motions of 20
to 25 knots. Progged 925mb temps are a degree or two warmer with
values btwn 22-23C, supporting highs well into the 80s most
locations. As always, some upstream convective debris clouds
could result in slightly cooler temps in some locations. A warm
and muggy night is on tap for Tues night with convection
dissipating by mid evening. Lows generally in the upper 50s to
mid 60s. Some patchy fog is possible, especially areas that get
rainfall on Tues.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 330 PM EDT Monday...Another day of unseasonably warm
temperatures is expected on Wednesday as upper level ridging
continues to build into the region. With 925mb temperatures around
+25C, daytime high temperatures will climb into the mid and upper
80s, with 90s possible in the broader valleys. Heat index values are
expected to stay below Heat Advisory criteria,but since it is so
early in the season there may be increased impacts due to lack of
acclimatization, especially for heat sensitive individuals; be sure
to stay hydrated, take frequent breaks, limit outdoor activities if
possible. Water temperatures across the region remain chilly, with
Lake Champlain near 60 degrees, so use caution and exercise cold
water safety if you plan on venturing out on local waterways.

Wednesday morning will feature mostly dry weather, but there might
be an isolated shower or thunderstorm during the afternoon given the
warm temperatures and an embedded shortwave providing enough
forcing. Chances of precipitation will increase heading into
Wednesday evening as a cold front approaches from the west. There is
still a little bit of uncertainty regarding the timing of the
frontal boundary, but it still looks like Wednesday evening through
Thursday will see some showers with embedded thunderstorms. The
severe potential looks a little weaker with this latest guidance,
with the best instability to the east, so while there will be some
embedded thunderstorms associated with the front, but the severe
potential is limited. Temperatures on Thursday will still be on the
warm side, with highs ranging from the upper 70s to mid 80s based on
the progression of the surface front.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 330 PM EDT Monday...A period of seasonable temperatures and
drier weather are expected across the region heading into Memorial
Day weekend as ridging builds overhead in the wake of a cold front.
Temperatures will be quite pleasant, especially after the recent
heat, with high temperatures in the upper 60s to mid 70s and
dewpoints only in the 40s. Overnight lows will be seasonable as
well, with temperatures in the upper 40s to low 50s. Some chances
for showers return towards the beginning of next week.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Through 06Z Wednesday...All terminals are currently VFR and they
should mostly stay that way through the night. Patchy fog will
develop in parts of the region later tonight but it will likely not
occur at any of the terminals. The one terminal that could see fog
is SLK but even there it looks unlikely at this point. Any fog would
lift shortly after sunrise. LLWS has developed at some of the
terminals and the rest have wind shear that is just below LLWS
criteria. The wind shear will continue tonight before diminishing
after sunrise as mixing occurs. Scattered showers and thunderstorms
will develop across the region tomorrow afternoon. The heaviest
storms will cause visibilities to briefly lower to MVFR or IFR.
However, most of the time during the day will be dry and VFR. The
best chance for thunderstorms looks to be between 17Z-02Z. Winds are
currently light and southerly and they should generally remain that
way throughout the TAF period. The exception will be in and around
any storms where strong convective wind gusts may occur.

Outlook...

Wednesday: VFR. Scattered SHRA, Isolated TSRA.
Wednesday Night: VFR. Chance SHRA, Slight chance TSRA.
Thursday: VFR. Chance SHRA, Slight chance TSRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
-- End Changed Discussion --

&&

.CLIMATE...
Record High Temperatures:

May 22:
KBTV: 93/1977
KMPV: 90/1994
KMSS: 89/1977
KSLK: 91/1911


Record High Minimum Temperatures:

May 22:
KBTV: 70/1911
KPBG: 65/1975
KSLK: 63/1921

May 23:
KPBG: 65/1964

&&

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

&&

$$
SYNOPSIS...Taber
NEAR TERM...Myskowski/Taber
SHORT TERM...Kremer
LONG TERM...Kremer
AVIATION...Myskowski
CLIMATE...Team BTV