-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 231719
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
119 PM EDT Wed May 23 2018

.SYNOPSIS...
A weak cold front will cross the area today with little fanfare
other than a few isolated showers or a stray storm across
eastern counties. Otherwise high pressure will provide fair and
seasonably warm temperatures through Friday. More uncertainty
arrives by the upcoming weekend as an increase in moisture and a
cold front sinking southward from Canada may lead to a period
or two of showers, especially Saturday and Saturday night.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1020 AM EDT Wednesday...Overall forecast is in good shape
with just a few tweaks to sky cover and precip probs for the
next few hours. Front lies north of the border and is currently
interacting with some stable low clouds inhibiting any
convective development. Once it crosses the border, better
instability will exist so still think slight to low chance of an
isolated shower and/or thunderstorms looks good through the
afternoon across northeastern areas.

Prior discussion...
After areas of patchy morning fog and low clouds burn off, a
much better day is on tap for our area as skies trend partly
sunny under drying northwesterly winds. A weak cold front will
be dropping southward through the area by this afternoon, behind
which those winds could gust into the 15 to 20 mph range in the
100-700 pm time frame. Some weak instability and meager
moisture convergence could also spark an isolated shower or
storm across mainly eastern and northeastern VT during this time
period as the front passes, but a warm layer near 600 mb should
inhibit any convective cells from attaining overly robust
levels. High temperatures will respond nicely to the increase in
overall sunshine, topping out in the lower to mid 70s north and
mid to upper 70s south which agrees nicely with modeled 18-21Z
925 mb thermal profiles.

Then trending mainly clear over time tonight as high pressure
builds east from the Great Lakes and Ohio Valley. I stuck close
to a multi-model bias-corrected blend for low temperatures
offering values in the lower and mid 40s in the broader valleys
and from 35 to 40 across Green and Adirondack Mountain
communities with some slight variability. Winds light.

By Thursday the surface high builds atop and just east of our region
by afternoon as light north/northwesterly flow trends south to
southwesterly over time. High temperatures cool slightly (3-5
degrees) from today`s values, but all and all another outstanding
day is on tap with nil pops under mostly sunny skies.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
As of 407 AM EDT Wednesday...Heights will be rising through the
evening hours as high pressure continues to build heading into
the weekend. Southerly flow will become westerly by mid day on
Friday and temps will warm rapidly. The westerly warm air
advection will bring 925mb temps of 18C to 21C over the region
meaning low to mid 80s can be expected. In the Champlain valley
we could see temps warm into the mid to upper 80s as BUFKIT
soundings show we will mix up to around 890mb. With that mixing
we`ll also see slightly drier dew points along with fairly gusty
winds. Expect gusts during the morning and afternoon hours of
between 25-30 mph. With the higher temps and decent mixing
there`s some potential for showers to develop in the afternoon
hours on Friday. Showalters turn negative across much of
Northern Vermont and Northern New York after 12pm. Any showers
would be isolated in nature but I certainly can`t rule out the
threat.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 407 AM EDT Wednesday...The weekend still presents itself
as a challenging forecast. Saturday night still seems like the
time period where we`ll have the best chance for rain but
confidence isn`t real high on any solution. The ridge starts to
break down Friday night as a front starts to drop south over
the North Country. This will bring in rain along with an
increase in cloud cover. Then its still a question of where does
the front stall out. I`m still leaning towards the front
stalling out to our south which means that we`ll be looking at
possible chances for rain heading into Sunday. QPF from the
global guidance is showing a bulls eye of zero rainfall during
the day on Sunday. Based on the placement of the bullseye and
upper level support I`m leaning towards the idea that we`ll see
a modified marine airmass over Vermont with the continental
airmass over northern New York. 925mb temps show a wedge of
cold air with easterly flow over VT/NH and warm air over NY. So
we may be too stable to be able to develop much in the way of
precip on Sunday across the Champlain Valley and east across
Vermont. I dont have a lot of confidence in that however.

Coming out of the weekend an upper level trough does swing
through the North Country and showers continue Monday into
Monday night. We`ll return to near normal temps with dry air
moving in as a dome of high pressure builds in for Tuesday and
Wednesday.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
Through 18Z Thursday...VFR conditions are expected through the
period. Diurnal cumulus developing over the region this
afternoon may produce a stray shower or isolated thunderstorm
across northern Vermont, but will dissipate to mainly clear
skies after sunset. Overnight, SKC to FEW250 is expected with
light winds, with more fair weather clouds developing across the
region tomorrow.

Outlook...

Thursday Night: VFR. NO SIG WX.
Friday: VFR. Slight chance SHRA.
Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Saturday: Mainly VFR, with local IFR possible. Chance SHRA.
Saturday Night: MVFR/IFR conditions possible. Likely SHRA.
Sunday: Mainly VFR, with local IFR possible. Chance SHRA.
Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Memorial Day: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance TSRA.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...JMG
NEAR TERM...JMG/Lahiff
SHORT TERM...Deal
LONG TERM...Deal
AVIATION...Lahiff