496
FXUS61 KBTV 180633
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
233 AM EDT Sat Jul 18 2026
.WHAT HAS CHANGED...
As of 232 AM EDT Saturday...
No significant changes.
&&
.KEY MESSAGES...
As of 232 AM EDT Saturday...
1. Thunderstorms and heavy rain this afternoon and evening.
2. Seasonably cool weather and intervals of wildfire smoke
expected over the next few days.
3. Frontal passages bring chances for showers and thunderstorms
Tuesday night into Wednesday before high pressure dominates our
weather on Thursday and Friday.
&&
.DISCUSSION...
As of 232 AM EDT Saturday...
KEY MESSAGE 1: An anomalously strong low for the time of year (~995 mb)
will track eastward from Ontario through southern Quebec today and
tonight. Showers will be more widespread close to the international
border as the warm front and center of the low will be closer. A
powerful cold front will come through in the afternoon and evening,
bringing a round of showers and storms. The airmass ahead of the
system will be relatively cool and not conducive to high
instability. Peak mean HREF SBCAPE values are around 500-750 J
during this time frame and earlier rounds of showers/clouds could
prevent enough heating to reach these values. However, due to the
strength of the low, there will be strong shear and dynamics. 0-6 KM
shear is forecast to be in the 40-50 KT range. One thing lacking
will be a significant surface wind shift/convergence with the front,
with southwesterly synoptic flow expected behind the front until the
center of the surface low pushes east. Height falls will be quite
significant though. The main threat from the storms is by far the
damaging winds, but there is a large amount of helicity where some
low level rotation will be possible. Based on this information, the
SPC continued the region in a split between a slight and marginal
risk. These storms will contain heavy rain, but with strong
background flow, the storms will move quickly and minimize the
flooding threat. There also does not look to be a stalled axis of
rain along the warm front on the front side that often occurs in
these setups. However, the threat for flooding cannot be completely
ruled out if areas see multiple rounds of heavy rain, with the
greatest threat of that being along the international border. In
summary, it is a conditional severe threat where little to no
development could happen, but if just enough solar heating does
occur, there could be several strong and severe storms this
afternoon and evening.
KEY MESSAGE 2: Highs look to be in the 70s to mid 80s over the next few
days, with slightly cooler conditions on Sunday. Lows will generally
be in the 50s and dew points will be relatively low. The wildfire
smoke makes a return for today as flow becomes westerly to
southwesterly, bringing the smoke that is currently over the Midwest
and Great Lakes into the region. Thankfully, behind the cold front
on Saturday, winds eventually become northwesterly and push the
smoke back to the south. The source of the smoke is fires in western
Ontario.
KEY MESSAGE 3: A cold frontal boundary and upper level trough are both
expected to cross the forecast area Tuesday night into Wednesday,
bringing another round of showers with embedded thunderstorms. By
Thursday morning surface high pressure will begin to ridge into the
north country, bringing a return to drier weather once again. Headed
into the weekend not a lot of model agreement on what will happen.
Will monitor the mid week period for potential strong or severe
storms as well as heavy rainfall. Highs for the mid and late week
are expected to be around the 70s and lower 80s with lows in the
upper 40s to lower 60s, though this may depend on how exactly the
atmospheric pattern shapes up during this period.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday...Quiet/VFR aviation weather conditions are
expected to prevail through 12Z Saturday. Light rain showers are
spreading across our area overnight, but not expecting any
reductions below VFR as activity remains light. Light and
variable winds overnight will become southerly after sunrise
with increasing gustiness; gusts to 25 kts are expected at BTV,
especially during Saturday afternoon. A low level jet will also
cross the region from SW-NE starting around 12Z-15Z, so LLWS is
forecast at most of the TAF locations except RUT. Included some
visibility restrictions during the daylight hours Saturday in
haze and wildfire smoke. In terms of precipitation, currently
seeing a leading band of -SHRA, followed by a stronger line of
showers and possibly embedded thunderstorms during the late
afternoon into the early evening hours. A few storms could be
strong to severe late in the day, but are not currently
mentioned in the TAFs due to uncertainties related to timing and
spatial coverage of activity. Brief heavy rainfall and gusty
winds will be possible.
Outlook...
Sunday: Mainly VFR, with local MVFR possible. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: Mainly VFR, with areas MVFR possible. Likely SHRA,
Chance TSRA.
Tuesday Night: Mainly MVFR, with local IFR possible. Definite
SHRA, Chance TSRA.
Wednesday: MVFR/IFR conditions possible. Likely SHRA, Chance
TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Air Quality Alert from 6 AM this morning to 11 PM EDT this
evening for VTZ001>011-016>021.
NY...Air Quality Alert until midnight EDT tonight for NYZ026>031-
034-035-087.
&&
$$
WHAT HAS CHANGED...Myskowski
DISCUSSION...Myskowski/Neiles
AVIATION...Neiles
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