413
FXUS61 KBTV 211918
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
318 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 WEDNESDAY NIGHT/...
As of 316 PM EDT Tuesday...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 THROUGH 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 TUESDAY/...
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 /19Z TUESDAY THROUGH SUNDAY/...
Through 12Z Wednesday...Isold to scattered thunderstorm activity
may impact TAF locations 19-23Z across VT and northern NY this
afternoon/early eve. Brief heavy rainfall and gusty winds are
possible, along with dangerous cloud-to-ground lightning.
T-storm activity dissipates later this evening with mainly scattered
midlevel (VFR) cloudiness. May see BR/FG formation east of the
Green Mtns, especially in the CT River Valley, during the pre-
dawn hours on Wednesday. During Wednesday morning, VFR
conditions expected with just FEW-SCT200-250. Winds generally
light S-SW across the region this afternoon away from any
thunderstorm activity.

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. NO SIG WX.
Saturday Night: Mainly VFR, with local IFR possible. Slight
chance SHRA.
Sunday: Mainly VFR, with areas MVFR possible. Slight 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
SHORT TERM...Verasamy
LONG TERM...Verasamy
AVIATION...Banacos
CLIMATE...Team BTV