049
FXUS61 KBTV 142343
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
743 PM EDT Tue May 14 2024

.SYNOPSIS...
Showers and thunderstorms will wind down overnight tonight, but the
unsettled weather pattern will continue over the next few days.
Several rounds of showers are expected through the rest of the week,
with Friday having the best potential to remain mostly dry.
Temperatures will remain seasonable through the weekend as well,
with highs generally in the 60s and 70s and lows in the 40s and 50s.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 730 PM EDT Tuesday...As expected, the thunderstorms late
this afternoon have been mostly garden variety, with a couple of
stronger cells producing quarter inch to half inch hail. A
severe-warned storm earlier produced 33 kt gust at Plattsburgh,
but no damage were reported. The cold waters of Lake Champlain
stabilized storms as they crossed over from northern NY into VT,
although marginal shear of around 25 kt near the international
border along with 6C/km mid level lapse rates have allowed the
storms to produce lightning again as they leave the Champlain
Valley. Not expecting anything severe especially with the
imminent loss of daytime heating, although brief locally heavy
downpours can still occur along with rumbles of thunder. Across
central and southern VT, daytime heating pushed temperatures
into the upper 70s to around 80, but the instability is not
colocated with the best dynamics so they have mainly missed out
on the convection and rainfall. Otherwise, forecast remains on
track so only made minor tweaks to bring it up to date.

PREVIOUS DISCUSSION...Scattered showers with isolated
thunderstorms will continue through the rest of this afternoon
into the evening hours, especially from the Adirondacks eastward
into north- central/central VT. The main threat from this
activity will be briefly heavy rainfall. Given fairly
unidirectional flow and a slow moving frontal boundary just to
our north, training of cells will be a concern. Flooding is not
anticipated, but ponding of water in poor drainage areas will be
possible, especially in locations that see multiple
showers/storms. Otherwise, have already seen one or two more
robust thunderstorms this afternoon, with a couple of reports of
small hail. Strong winds will be possible in stronger storms,
as well. Strong storms will continue to be possible through 7 pm
or so, and while an isolated marginally severe thunderstorm
can`t be totally ruled out, the risk is low with widespread
severe not anticipated.

Showers and thunderstorms will wind down this evening as we lose
daytime heating and instability. The front will make a slow push
southward overnight, eventually hanging up somewhere over
northern/central portions of our forecast area. Moisture will linger
however, keeping plenty of clouds around. Some patchy fog or drizzle
will be possible as well. The moisture will also serve to keep
temperatures from cooling much overnight, and lows will be in the
50s areawide.

The front will lift back north on Wednesday, allowing showers to
once again develop, especially in the afternoon. Moist profiles and
poor lapse rates will limit instability, so not anticipating any
thunderstorms. With little in the way of sunshine, highs will be
cooler than today, especially in central/southern sections. Highs
will be in the mid 60s to around 70F. Like today, showers will wane
in the evening as we lose daytime heating. Lows will be similar to
tonight, perhaps a few degrees cooler.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 336 PM EDT Tuesday...On Thursday there will be pretty
pronounced upper level ridging that will stifle any showers that can
develop in weakly unstable environment. Overall the pattern should
support mainly dry weather between isolated, slow moving and light
showers. High temperatures should be a few to several degrees warmer
than on Wednesday with more low level dry air and lower cloud cover,
especially as one goes west. While winds will be light, there seems
to be some uncertainty as to the low level flow. The latest forecast
shows greater northerly flow down the Champlain Valley associated
with Canadian high pressure nosing southward, while a weak
southeasterly low level regime develops in eastern Vermont tied to
the closed low drifting over the western Atlantic. Overall, between
this low level flow and a ton of dry air aloft I don`t foresee any
significant shower activity despite the 30-50% PoPs during the day,
with greatest chances of rainfall generally in northern Vermont
shifting eastward with time. Any diurnally driven, light showers
should taper off quickly Thursday night with lack of any large scale
forcing and continued height rises. Would expect patchy fog could
develop overnight in the typical, localized valley locations with
light wind and probable clearing skies. Many areas should fully
decouple which will probably see lower temperatures than currently
indicated, but there is no threat of frost conditions with a
relatively mild air mass in place.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 336 PM EDT Tuesday...The large scale weather pattern doesn`t
look to change much through early next week with a tendency towards
troughing. The resulting unsettled weather will remain largely
unimpactful due to deeper moisture being shunted south of the area
by convergent upper level flow. One notable shift in the forecast
has been towards warmer conditions on Friday as brief ridging builds
in. Probabilities of temperature exceeding 80 are now in the 35-45%
range in a large swath of the Champlain Valley, and 20-35% in some
other valley locations such as along the I-89 and I-91 corridors. So
mid to upper 70s look to be rather common with spot 80 degree
values, which would make it the warmest day so far this spring for
many spots. The NWS HeatRisk product suggests the warmth could
affect those who have extreme sensitivity to heat, especially given
we`ve been mostly on the cool side recent. However, with some clouds
and moderate humidity, it doesn`t look noteworthy as indicated by
the WBGT values below the elevated threshold.

A very weak cold front approaching from the west brings us higher
chances of showers in northern New York by Friday night spreading
areawide through Saturday. With no significant moisture or wind
fields, would think no more than a brief downpour with this system.
Moving into Sunday there remains some uncertainty with regards to
the upper level pattern but still favoring a trough with some shower
chances and lack of substantial instability. Most global model
clusters favor height rises with a warmer day on Monday compared to
Sunday, although about half of the 12Z EPS members do show a closed
low to our northwest that point to a possible change in the forecast
moving forward for early next week. More of the same for Tuesday so
NBM temperatures near to a bit above normal both days look
reasonable at this time along with largely 15 to 30% PoPs.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...Scattered showers and a few
thunderstorms, one southwest of KEFK and one south of KSLK, are
progressing east across the region. Activity has been mainly
scattered, with only localized impacts. But reductions to 2SM to
5SM are possible for any terminal to take a direct hit as
scattered showers and storms continues through about 04z before
thunder is completely out of the picture. Tonight`s main
challenge is whether there will be drizzle or patchy fog along
the international border impacting KEFK, KMSS, and KPBG from
about 05z to 11z tied to a surface boundary. The picture isn`t
clear on which it will be and when so have stuck to a blend of
4SM and 1500-2500 ft agl ceilings. Winds light and variable
through about 12z. About 15z-16z, surface stationary front
strengthens and numerous showers will begin to develop with
ceilings falling to 1000-2500 ft agl and visibilities 3 to 6SM
in heavier showers. There could be some improvement late in the
day at KRUT and KMPV to VFR. Winds will become south to
southwest 4 to 8 knots, but remain northeast at KMSS. Shower
activity wanes after 22z.

Outlook...

Wednesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Thursday: Mainly VFR, with local MVFR possible. Chance SHRA.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. Slight chance SHRA.
Friday Night: VFR. Slight chance SHRA.
Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Saturday Night: MVFR/IFR conditions possible. Chance SHRA.
Sunday: Mainly MVFR, with areas VFR possible. Chance SHRA.

&&

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

&&

$$
SYNOPSIS...Hastings
NEAR TERM...Chai/Hastings
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Haynes