145
FXUS61 KBTV 191821
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
221 PM EDT Wed Aug 19 2026
.WHAT HAS CHANGED...
As of 220 PM EDT Wednesday...
No significant changes were made to the forecast.
&&
.KEY MESSAGES...
As of 220 PM EDT Wednesday...
1. Showers are expected to continue this afternoon and evening
before drier and seasonable weather returns as we head into the
weekend.
2. Showers and thunderstorm chances increase by the end of the
weekend with unsettled weather continuing into early next week.
Temperatures will be relatively seasonable through the extended
period.
&&
.DISCUSSION...
As of 220 PM EDT Wednesday...
KEY MESSAGE 1: A dying cold front is approaching northern New York and
Vermont from Canada this afternoon, producing some showers out ahead
of it. The forcing will decrease as it moves east through northern
New York, but enough instability is out there to allow the showers
to continue into Vermont. A couple embedded thunderstorms are
possible as well. While sufficient deep layer shear will be in place
for potentially strong storms, low instability, some dry air aloft,
a lack of well-defined surface boundary, and pre-existing
clouds/showers will be working against it. Therefore, an isolated
strong to severe storm is not likely this afternoon, but cannot be
completely ruled out. Any storms will fall apart as they try to push
southeast this evening and southern areas should remain mostly dry.
Chances of lingering showers overnight are around 10-40%, mainly
near the international border. High pressure will build down from
Canada to end the week and start the weekend, bringing cooler
temperatures and lower humidity. Lows tonight will be seasonable in
the 50s, then cooling late week into the 40s and 50s. Highs through
Saturday will be seasonable, with temperatures rising into the 70s
and low 80s each afternoon. Next chance of precipitation arrives
later Saturday afternoon onward.
KEY MESSAGE 2: A quasi-double barrel pattern will develop by late
Saturday with competing pieces of energy, one over central-eastern
Ontario, and a coastal low in southern New England. Models depict a
deepening trough over the Great Lakes by Saturday with a coastal low
riding along the coast of southern New England. The deepening of the
Great Lakes trough will help amplify our flow pattern aloft Saturday
night into Sunday, likely accelerating the coastal low
northeastward. A few showers will be possible on the periphery of
the coastal low Saturday night in southeastern Vermont, though
majority of Vermont will stay dry Saturday and Saturday night. In
northern New York, the Great Lakes trough will lead to increasing
shower chances late Saturday into Saturday night across the St.
Lawrence Valley and northwestern Adirondacks. Questions linger on
how much moisture will be sandwiched between the two systems closer
to Sunday morning, as it pertains to precipitation chances in
Vermont. Currently there is a 35-50% chance of rain Sunday morning
for much of Vermont, though these values may increase or decrease
with how the trough amplification occurs. A more delayed
amplification could keep the coastal system from racing east with a
moisture interaction in the area between the system Sunday morning.
A faster amplification will likely lead to less system interactions
and perhaps a dry Sunday morning. Regardless, as the Great Lakes
trough translates east Sunday, everyone will see periods of rain,
and perhaps some thunderstorms should enough clearing take place to
allow instability to grow. Temperatures will start off on the warmer
than average side in the upper 70s to low 80s, though with the
approach of clouds and showers, temperatures by Sunday will begin a
gradual decrease back to seasonable levels.
The main piece of energy departs late Sunday, though cyclonic flow
about a trailing upper low over eastern Ontario will keep some
shower chances around. Lingering showers will be focused over the
higher terrain Monday and Tuesday afternoon, mainly diurnally
driven. Sky cover Monday and Tuesday will favor more clouds then sun
as a result of the scattered shower chances. Temperatures will
remain on the seasonable to potentially slightly below seasonable
levels Monday and Tuesday with highs in the low to mid 70s.
Temperatures will rebound by mid week with subtle ridging building
over eastern New England.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Through 18Z Thursday...A slow moving cold front is moving through the
region, weakening as it moves east. The boundary is broken into two
parts. An initial area of isolated light showers and drizzle
currently from eastern Franklin County VT to SLK, and a secondary
area of more moderate scattered showers in the St. Lawrence Valley.
The first round will be unimpactful showers for EFK/BTV/PBG/MPV.
However, the second round could bring brief MVFR vsbys under any
showers, with higher confidence in any reductions at MSS/SLK for the
next hour or two. Confidence wains as this secondary boundary slides
east, though about a 30% chance for any vsbys reductions exists at
BTV/PBG/EFK/MPV. RUT should remain dry through this afternoon. The
front then washes out over the area with lingering low level
moisture for tonight. The question then becomes does this moisture
scour out in the mid levels for fog potential, or does this low
level moisture remain fairly thick with more low level stratus.
Regardless, most sites will likely see some reductions at least to
MVFR cigs and vsby tonight with moisture lingering. Confidence in
fog will increase should a terminal receive a shower close to sunset
or 23-01Z. Models depict some easterly flow at BTV which could draw
some VCFG at the least near sunset. Highest probabilities for fog
(around 40-50%) exist at SLK/MPV, with slightly lower probs (30-40%)
at MSS/EFK. Trends upstream suggest low stratus may initially spread
over the area transitioning to more fog closer to sunrise. Any low
clouds scour out by tomorrow morning with mainly high clouds through
the end of the TAF period. Winds will generally remain west to
southwest today, becoming light and variable overnight into tomorrow
morning.
Outlook...
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday Night: Mainly VFR, with areas MVFR possible. Chance
SHRA.
Sunday: Mainly MVFR, with areas VFR possible. Likely SHRA, Slight
chance TSRA.
Sunday Night: Mainly VFR, with local IFR possible. Chance SHRA.
Monday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight
chance TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Storm
DISCUSSION...Storm/Danzig
AVIATION...Danzig
|
