035
FXUS61 KBTV 030219
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1019 PM EDT Thu May 2 2024

.SYNOPSIS...
After lingering showers in far northeastern Vermont wind down,
dry conditions in the wake of a cold front will continue
overnight. Some low clouds and fog will be possible overnight,
then skies should become partly to mostly sunny on Friday. Some
rain showers will enter northern New York on Saturday, and the
entire region for Sunday. Aside from the cooler and wetter
weather on Sunday, largely seasonable weather is expected over
the next week.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 1009 PM EDT Thursday...No major changes were needed to the
forecast with this update, only some minor tweaks to reflect
recent observations. Some lower cloud cover can be seen across
the northern portion of the forecast area, with some mist and
fog beginning to develop in some locations, although mostly
clear skies are still found further south.

Previous Discussion... A cluster of rain showers is currently
skirting through far northeastern Vermont late this afternoon.
It is associated with a cold pool aloft as heights fall in the
base of the upper trough swinging southeastward behind the
surface cold front that is now well east of our region. The
pressure gradient behind the front is weak such that winds have
only been around 10 to 15 MPH, and the northwesterly winds
should diminish, as will any lingering light rain
showers/sprinkles, after sunset.

While anticyclonic flow will lead to continued dry weather
overnight, the question remains as to how much fog and/or low
stratus develops. Expect our mountains to be obscured by low
clouds overnight due to a subsidence inversion and lingering
moisture. Otherwise, have offered patchy fog largely where it
rained this afternoon/early evening in northern/northeastern
Vermont. However, conditionally areas of fog will develop in
portions of northern New York where skies clear out. Compared to
areas farther east, 925 millibar flow looks particularly light
overnight. In contrast, light southeasterly flow suggests
stratus will be more prominent east of the Green Mountains.

For Friday into Friday night, no significant weather is expected
with ridging building into our region. Temperatures have trended
a touch warmer, with most likely highs now exceeding 70 in just
about all of the Champlain Valley in addition to the St.
Lawrence Valley. The aforementioned southeasterly flow will
dampen warming in central and eastern Vermont a bit, but it
should be a largely pleasant day once morning shallow clouds
dissipate. Towards the very end of the period shower chances
develop across our western areas, but there is quite a bit of
model disagreement on if the upper level forcing is sufficient
to get enough lift to support precipitation. The incoming wave
looks to peter out as it runs into a strong ridge, so mainly we
will see increasing cloud cover and mild temperatures with an
increase in southerly wind Friday night.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
As of 323 PM EDT Thursday...PWATs rise to 2 standard deviations above
normal on Sunday as moisture with Gulf of Mexico origin looks to
overspread the region. Forecast soundings show a lack of surface-
based instability, so showers with brief locally heavy downpours
look to be the main risk. While there could be embedded thunder due
to elevated instability, no organized thunderstorms are anticipated.
It will be quite breezy as well, with persistent southeast winds
gusting 30-35 mph at times. Rainfall chances wise, it does look like
areas east of the Adirondacks should stay dry for most of Saturday.
This is because while a shortwave trough moves eastward from the
Great Lakes, it encounters a stout omega block, and therefore the
best forcing is diverted north of our region on Saturday. While
there should be plenty of cloud cover, have utilized the 75th
percentile of model guidance for Champlain Valley and point east.
Highs should top out right around 70, or a few degrees above
climatological norm for early May across the Champlain Valley.
Expect 60s elsewhere, except 50s in the high terrain. Heading into
Sunday, the omega block finally moves east, allowing the shortwave
trough to approach closer to our CWA albeit in a deamplified state.
This means that PoPs increase to the likely category with scattered
to perhaps numerous showers on Sunday. While there would likely be
widespread wetting rainfall, QPF amounts are quite manageable in the
0.25 to 0.5 inch range. Indeed, the MMEFS shows none of our area
rivers going into action stage.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 323 PM EDT Thursday...The overall weather pattern heading into
the first full week of May can be described as unsettled with no
real significant warm up or impactful weather. Unsurprisingly, the
CPC 8-14 day temperature outlook favors near normal temperatures and
leans towards above normal rainfall. For reference, typical highs
for North Country in early May are in the low to mid 60s, while
average overnight lows are in the mid 30s to low 40s. The upper
level pattern features a positively tilted omega block sandwiched
between an anomalously deep trough across the Rockies/northern Great
Plains and another trough over eastern Quebec/Newfoundland. H5
height anomalies favor a period of widespread showers and
thunderstorms in the Tuesday/Wednesday time frame, as positive H5
height anomalies give way to near normal values. Depending on the
timing of the associated surface cold front, ingredients may exist
for a few stronger storms. But with the potential storms being 5
days away, have largely stuck to a blend of guidance for this time
frame.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...Mostly VFR conditions currently at 6 out
of our 7 sites with low MVFR cigs at EFK. Highest confidence of
cigs going IFR in the next 1 to 2 hours is at EFK with
eventually LIFR/VLIFR developing in low clouds and fog with vis
around 1/2sm toward midnight. At our other sites anticipated
lower clouds in the MVFR range to redevelop over the next 1 to 3
hours, with localized IFR cigs at BTV/SLK/PBG and MPV possible
toward 06z. Have handle these sites with tempo groups to
highlight the 30 to 40% probability of IFR, with higher
confidence of IFR cigs after 06z, as low level flow becomes
strongly blocked and moisture is trapped below subsidence
inversion. Conditions improve to MVFR after 12z Friday and
mostly VFR by 15z, except some lingering MVFR cigs in the mtn
taf sites of EFK/SLK and MPV. North/northeast winds at 4 to 8
knots this evening will become mostly light and terrain driven
by 03z and continue into Friday morning.

Outlook...

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

&&

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

&&

$$
SYNOPSIS...Kutikoff
NEAR TERM...Kremer/Kutikoff
SHORT TERM...Chai
LONG TERM...Chai
AVIATION...Taber