686
FXUS61 KBTV 220136
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
936 PM EDT Tue May 21 2024

.SYNOPSIS...
Isolated to scattered thunderstorms are expected to continue
late this afternoon into early this evening, generally
dissipating before midnight. A few storms may be strong to
severe through this evening, with localized strong winds and
small hail the primary threats. A warm overnight period is
expected, followed by hot and moderately humid conditions across
the North Country on Wednesday. High temperatures may reach 90
degrees in a few valley locations. A few thunderstorms are
possible Wednesday afternoon, with isolated to scattered
thunderstorms possible Wednesday night into Thursday in
association with a cold front approaching from the eastern Great
Lakes region. Somewhat cooler and drier conditions return on
Friday into the holiday weekend, but temperatures will remain
above seasonal averages for late May.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 930 PM EDT Tuesday...Convection is winding down at this
hour. The most concentrated activity stretches from the
Champlain Valley westward into the central Adirondacks, with a
few rumbles of thunder being noted. The latest mesoanalysis from
SPC shows little in the way of available instability remaining,
so expect the remaining showers to continue their downward trend
in coverage and intensity over the next couple of hours.
Otherwise, expect a somewhat muggy night with temperatures
remaining in the 60s in most spots. Forecast generally remains
on track; only changes were some minor tweaks to PoPs to match
the latest radar trends, and to remove enhanced t-storm wording
as strong/severe threat has ended.

Previous discussion...We continue to monitor ongoing strong
thunderstorms this afternoon, which have developed in advance of
a shortwave trough pushing eastward from far sern Ontario and
the eastern portion of Lake Ontario. The 18Z RAP-based SPC
mesoanalysis indicates that SBCAPE values have reached 1500-2000
J/kg across portions of the Adirondacks esewd into s-central
VT, along with nearly non-existent CINH. SFC-6km bulk shear of
25-30kts is sufficient for strong multicellular storms and
possible storm clusters as outflow interactions occur with
ongoing activity through this evening. A few severe storms are
possible, with localized damaging winds the primary threat.
Given convective mode and WBZ heights of 9-10KFT, anticipate
mainly sub-severe hail, but certainly some small hail will be
possible with any stronger cores through 00Z. Thereafter,
diminishing instability should allow overall intensity and
extent of convection to wane later this evening. Upstream
shortwave and associated forcing appears to translate close to
the intl border region overnight, so could see some continued
showers and a few rumbles of thunder into the overnight hours
across the far north. Otherwise, relatively mild overnight with
lows mainly in the lower 60s, except mid-upr 50s across the
Adirondacks and far nern VT. May see some patchy fog during the
pre-dawn hours, mainly confined to the deeper valleys of eastern
VT given 20-25kt winds in the 1-2kft AGL layer causing some
turbulent mixing in most locations overnight.

On Wednesday, a 700mb shortwave ridge builds across the North
Country with a building 850mb thermal ridge across Northern New
England. Lesser precipitation chances and better insolational
heating should allow temperatures to reach 90F at BTV and a few
other locations within the Champlain Valley and upper CT River
Valley. Generally mid-upper 80s elsewhere. Heat index valleys reach
91-92F during the afternoon with mid-60s dewpoints. Just below heat
advisory criteria, but we will continue to message the hot and
moderately humid conditions (and warmest day of the year thus far).
May see an isold tstm Wednesday afternoon, but better height falls
and slightly cyclonic 700-500mb flow Wednesday night suggest better
coverage of showers and a few embedded thunderstorms developing
during Wednesday night. PoPs generally 30-50% Wednesday night. Lows
should be in the low-mid 60s Wednesday night as S-SW winds 5-9 mph
persist thru much of the night.

&&

.SHORT TERM /THURSDAY NIGHT/...
As of 210 PM EDT Tuesday...A surface cold front comes through on
Thursday with height falls and temperatures aloft falling during the
day from west to east. Dew points should fall rather quickly into
the 50s by the morning hours across northern NY, and then in the
afternoon across Vermont. As such, the best chance for decent shear
to overlap with surface-based instability is across Central and
Southern Vermont on Thursday afternoon. This is where the forecast
indicates better chances for thunderstorms. Thinking is still that
while a few stronger storms are possible, they should stay mainly
below severe criteria.

Temperatures will see highs in the low 70s to mid 80s across
Vermont, with cooler temperatures in the low to mid 70s across
northern NY.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 210 PM EDT Tuesday...A return to seasonable conditions is
expected after the passage of the cold front on Thursday. While
expecting a mostly dry holiday weekend, a few showers and possible
thunderstorm, especially on Saturday afternoon, cannot be ruled out.
Overall the region should expect highs over the weekend in the upper
60s to mid 70s with dew points in the 40s and 50s, a welcome change
from the muggy conditions from earlier this week. Looking into next
week, weather looks unsettled as a few systems move into the region
Monday through the mid week.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...Scattered strong thunderstorm activity
will wane through 02z, with local IFR possible through that
time. Brief heavy rainfall and gusty winds will be the main
threats, along with small hail. Activity wanes after 02z, with
VFR conditions to prevail through the remainder of the TAF
period thereafter. The exception will be some localized MVFR
visibilities in patchy fog 09-12z, mainly at KMPV. Winds
generally light south-southwest overnight into Wednesday.

Outlook...

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. Chance SHRA.
Saturday Night: Mainly VFR, with local IFR possible. Chance SHRA.
Sunday: Mainly VFR, with areas MVFR possible. Chance SHRA.

&&

.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...Banacos
NEAR TERM...Banacos/Hastings
SHORT TERM...Verasamy
LONG TERM...Verasamy
AVIATION...Hastings
CLIMATE...Team BTV