403
FXUS61 KBTV 042325
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
725 PM EDT Sat May 4 2024

.SYNOPSIS...
Dry weather will give way to widespread rainfall on Sunday
along with breezy conditions. High pressure will bring dry and
mostly sunny weather to start the new work week. The next chance
for widespread rainfall and potential thunderstorms arrive
middle of the week.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
As of 722 PM EDT Saturday...Its a beautiful evening acrs our fa
with partly cloudy skies and comfortable temps in the 60s to
near 70F. Hope you enjoyed todays weather, because changes are
on the way for Sunday. Have increased pops to 100% for Sunday as
a widespread wetting rainfall is anticipated with qpf ranging
btwn 0.25 and 0.75. A cool, raw and wet day is anticipated with
localized breezy south/southeast winds likely from time to
time. Did make some minor tweaks to cloud grids this evening,
temps, and winds, but overall fcst in good shape.

Previous discussion follows:
It has turned out to be a fairly pleasant early May day across
North Country with upper ridging overhead mitigating the low-
level maritime flow from coastal New England. KCXX radar shows
some reflectivity returns across our southwestern and southern
zones but much of these are just virga with plenty of dry air in
the lower levels of the atmosphere. The partial sunshine has
allowed temperatures to warm into the upper 60s to low 70s with
even some isolated 73-74 degree readings despite plenty of cloud
cover. Overnight tonight, the omega block weakens and moves
east, allowing a piece of weak shortwave energy to come up the
Ohio River valley. There are some hints of elevated instability,
but while a handful of rumbles cannot be ruled out, it should
be isolated enough to preclude mention of thunder with this
forecast package.

Heading into Sunday, PWATs rise to around 1.5 standard deviations
above normal as moisture with Gulf of Mexico origins overspreads the
region. Upper level pattern shows a stout omega block shifting east
of our area into Maine, increasing shower chances and coverage on
Sunday. However, organized convection is not expected as the main
jet energy associated with the shortwave trough moving eastward from
the Great Lakes is diverted into Quebec. As a result, the main
trough axis does not approach North Country until sometime middle of
next week. Indeed, forecast soundings show a lack of surface-based
instability, so scattered to numerous showers with brief locally
heavy downpours look to be the main risk. While there could be
embedded thunder due to elevated instability, the coverage is again
too isolated to mention in the forecast.

While widespread wetting rainfall is expected, rainfall amounts are
quite manageable in the 0.25 to 0.5 inch range with locally higher
amounts in the favored upslope regions of the Green Mountains and
Adirondacks. Indeed, the MMEFS shows none of our area rivers going
into action stage. Sunday will be about 10-12F cooler than Saturday,
with highs only in the 50s with low 60s possible if there are breaks
in the rain or clouds. In addition, a 40-50 kt 925mb southerly low
level jet overspreads the region during the day on Sunday. NAEFS
situational awareness ensemble table shows the v vector wind rising
up to 2.5 standard deviations above normal, so it will be a rather
breezy if not blustery day. A mitigating factor is that the waters
of Lake Champlain is still quite cold with water temperatures still
in the low to mid 40s, which is almost isothermal to the forecast
925mb temperatures in the +5 to +8C range. That could reduce the
mixing potential in the boundary layer, in addition to the
stabilizing effect of any rainfall. So have mostly kept wind gusts
in the 30 to 35 mph range across the Champlain Valley despite the
southerly wind component being anomalously strong. Overall, no
overall hazardous weather to speak of but Sunday does look to be a
less than ideal day for outdoor activities. Heading into Sunday
night, showers taper off and the boundary layer looks well mixed
enough to preclude widespread fog development. Temperatures stay
quite mild in the mid 40s to low 50s.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
As of 307 PM EDT Saturday...A few showers could linger on Monday from
a weak surface trough (QPF up to 0.03"), but precipitation chances
decrease throughout the day as drier air moves in. With this dry
air, clouds will be on the decrease as well on Monday, allowing for
mostly sunny skies by the afternoon. Resulting highs will be in the
mid 60s to lower 70s, a few degrees above average. Monday night,
clouds will mostly clear out and winds will be light/variable as
high pressure noses into the region from Hudson Bay. This will cause
lows to drop into the 40s for most. It`s possible for some patchy
fog to develop late Monday night into early Tuesday morning with the
favorable light winds and clearing skies. This will largely depend
on how much the skies do clear as some models hold onto some clouds
throughout the night.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 307 PM EDT Saturday...Ridging and surface high pressure will
keep Tuesday dry and mostly sunny. There could be some high clouds
arriving Tuesday afternoon/evening due to a trough hovering to our
northeast as well as another approaching system. Tuesday is likely
to be our warmest day of the long term period (through Saturday)
with highs in the upper 60s through mid 70s, several degrees above
average.

Precipitation chances will return by Wednesday as one of a few waves
follow the zonal flow aloft through the forecast area. Each day
through the end of the week could have some showers. Highs will take
a hit from these, mostly peaking in the 60s, and lows will be in the
40s and lower 50s for the remainder of the week. Frontogenetical
forcing and instability look most favorable Wednesday for some
thunderstorm chances, but instability and forcing are not impressive
enough for severe weather concerns at this time.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Through 18Z Sunday...Expect VFR conditions to persist for all
terminals through 12z Sunday. Winds are generally under 10 kt
out of the south or southeast, except for northeast at KMSS.
Channeled or terrain driven flow can result in 15 kt winds at
KPBG, KBTV and KRUT. After 12z Sunday, increasing shower
coverage will lead to ceilings lowering to MVFR for most
terminals. Additionally, LLWS increase to 45 kt at 2000 ft for
most terminals after 12z Sunday.

Outlook...

Sunday: Mainly MVFR, with areas VFR possible. Definite SHRA.
Sunday Night: Mainly MVFR, with areas IFR possible. Chance SHRA.
Monday: Mainly VFR, with local IFR possible. Slight chance SHRA.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Chance SHRA.
Wednesday: MVFR/IFR conditions possible. Likely SHRA.

&&

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

&&

$$
SYNOPSIS...Chai
NEAR TERM...Chai
SHORT TERM...Storm
LONG TERM...Storm
AVIATION...Chai/Taber