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Office: BTV

FXUS61 KBTV 170802

Area Forecast Discussion
National Weather Service Burlington VT
402 AM EDT Wed Aug 17 2022

After a mainly dry morning, widespread showers are expected later
this afternoon, lingering through Thursday as low pressure moves
northeastward across Maine. Drier and warmer conditions are expected
for the weekend.


As of 402 AM EDT Wednesday...Low pressure currently positioned
southeast of the 40N/70W benchmark will lift northward today and
tonight, eventually moving onshore near Penobscot Bay in coastal
Maine early Thursday. Plentiful cloud cover associated with this
system has already spread over the North Country, and expect we'll
have a couple of pretty cloudy days as the low slowly lifts to our
east. Rain showers will be a little slower to return, as we should
have a brief dry period this morning before rain moves back in
mid/late this afternoon into the evening hours. As we saw yesterday,
the showers will move from east to west as moisture and an inverted
trough wrap around the the low. Precipitation will be most
widespread in eastern VT through this evening, though at least
scattered showers will be possible all the way to the St Lawrence
Valley. The St Lawrence Valley is also the most likely to see any
sun today, and with that potential heating also comes the chance for
perhaps a thunderstorm or two. The wider valleys will see the
warmest conditions today, generally mid to upper 70s, with some
locations in the St Lawrence Valley topping 80F. Elsewhere, highs in
the upper 60s to low 70s will be common.

For overnight tonight and through the day on Thursday...widespread
showers gradually shift from eastern VT to become more focused in
the northern mountains the low lifts to our east. Winds will funnel
down the Champlain Valley overnight as they briefly turn north, so
it will likely be a bit breezy along Lake Champlain, though winds
should remain below Lake Wind Advisory levels. The flow will
eventually turn more to the northwest as the low starts to pull away
to the northeast through eastern ME, so rain will become steadiest
along the western slopes by mid-morning Thursday. However, overall
coverage will wane through the afternoon and evening as best forcing
and moisture begins to exit to the east. All told, rainfall totals
of a half to three-quarters of an inch are expected along and east
of the Greens, with a quarter to one-half of an inch for the
Adirondacks and Champlain Valley. West of the Adirondacks, rainfall
amounts will be a tenth of an inch or less. While temperatures won't
cool too sharply tonight due to the abundant moisture (lows will be
in the 50s), Thursday could be fairly cool, especially in eastern VT
due to thick cloud cover and cold air advection. Highs for the
western slopes of the Greens to the Connecticut River Valley will
remain in the lower to mid 60s, while lower to mid 70s are expected
in the Champlain and St Lawrence Valleys.


As of 402 AM EDT Wednesday...A deep and closed mid/upper lvl
circulation wl be lifting acrs eastern Maine, resulting in cyclonic
northwest flow over our fa. This combined with additional s/w energy
and lingering moisture in the 850 to 700mb layer wl produce a chance
for showers acrs central/eastern VT thru 06z on Friday, with highest
chcs acrs the NEK. Mid/upper lvl ridge builds into the eastern Great
Lakes and expands into the North Country on Friday into Saturday. A
general drying/warming trend wl be anticipated, with weak sfc high
pres overhead. Still cannot complete rule out a stray shower or two
during peak heating/instability acrs the dacks or portions of the
Greens on Friday aftn, but areal coverage with minimal
forcing/moisture wl be limited. Some patchy fog wl be possible on
Thurs night and again Fri night, but wl hold off for now, as
soundings indicate winds 15 to 25 knots at 925mb on Thurs night and
some mid lvl clouds lingering on Fri night. Temps mainly in the
upper 40s to near 60F for lows, with highs mid 70s to lower 80s,
with few locations mid 80s on Fri aftn, based on progged 925mb temps


As of 402 AM EDT Wednesday...Large scale pattern supports general
mid/upper lvl trof acrs the Ohio Valley into the NE CONUS for early
next week. This trof and associated pieces of energy wl result in an
unsettled pattern with chcs for showers/storms starting Sunday and
continuing into early next week. Still some disagreement with timing
of highest precip potential, as GFS is faster with lifting mid/upper
lvl trof and associated vort acrs our cwa on Tues, while ECMWF is
delayed by 6 to 12 hours. Given uncertainty in timing and still 5 to
6 days away we wl hold pops in the chc range (30-40%) for now and
make adjustments as event becomes better modeled by our guidance.
Wind fields don't look particular strong and sfc convergence is
weak, but with some sfc heating expecting CAPE values in the
800-1200 J/kg during the aftn hours, supporting some heavier
convective downpours. Did trim a few degrees off highs on Tues with
expectation of more clouds and potential showers, holding temps
mainly in the 70s. Otherwise, stuck close to NBM with temps in the
mid 70s to lower 80s and lowers mid 50s to mid 60s. Some increase in
humidity values are likely for early next week, associated with
southerly flow and pw values climbing over 1.5".


Through 06Z Thursday...Mainly VFR through much of the period
with local IFR/LIFR possible in patchy fog 06z-12z Wednesday.
KMPV and KEFK have the best chances of seeing fog. Mid-high
clouds will cover much of the region through at least 18z
Wednesday, but ceilings lower thereafter with widespread showers
moving in from the east. MVFR ceilings likely at all VT
terminals by 00z or so, and possibly at NY sites as well.
Visibility mainly unrestricted in showers, but KMPV, KEFK, and
KRUT could drop down to 5SM at times after 00z.


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




NEAR TERM...Hastings