537
FXUS61 KBTV 110729
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
329 AM EDT Thu Jun 11 2026
.WHAT HAS CHANGED...
As of 250 AM EDT Thursday...
A Heat Advisory was issued for today in eastern Windsor County
from 12 to 8 PM.
&&
.KEY MESSAGES...
As of 250 AM EDT Thursday...
1. Building heat and humidity will impact the region with
potentially dangerous conditions today in Windsor County and
more widespread for Friday.
2. Isolated to scattered thunderstorms are expected today with
a cold front potentially bringing stronger variety storms Friday
afternoon.
3. Strong cold front to bring widespread rainfall and
thunderstorms to the region late Sunday with more seasonal, yet
unsettled, weather for next week.
&&
.DISCUSSION...
As of 250 AM EDT Thursday...
KEY MESSAGE 1: Temperatures are slow to fall this morning with
more expansive cloud cover limiting radiational cooling. As
such, temperatures will start warm today with 925mb temperatures
ranging 23-25C. Mixing supports high temperatures in the upper
80s to around 90 degrees. Conditions will be a little
uncomfortable this afternoon with heat index values pushing 90
for most locations and mid/upper 90s in Windsor County. A heat
advisory was issued for portions of southern Vermont from 12 to
8 pm today. The saving grace for the Champlain Valley could be
cloud cover associated with convection. Some showers and a few
thunderstorms may form this afternoon limiting max temperatures
enough to be excluded from higher heat related concerns.
However, it will still be an uncomfortable day and caution is
advised since most are not acclimated to these conditions.
Friday, temperatures warm further as 925mb temps rise in the
23-27C range. Ridging will be sufficient to cap morning/early
afternoon convection from the Champlain Valley eastward, so heat
indices are expected to climb into the mid/upper 90s for the
Champlain Valley and portions of the Connecticut River Valley.
Timing of the front will play a part in heat stress for the
Champlain Valley, but current model output favors a post-4 PM
passage. Those in northeastern Vermont may be included in the
Advisory later if model warming trends continue. There is a
non-zero chance that heat indices could approach/exceed 100 for
a few locations, but have held back a little since some guidance
pushing these values has had recent tendencies to run a little
too warm. Should more of a consensus build in other model
output later today, excessive/extreme heat concerns will
increase.
KEY MESSAGE 2: With heat building and a weak trough moving
through the region today, some isolated to scattered
thunderstorms will be possible. Coverage of thunderstorms have
increased from previous forecasts mainly due to a more
consolidated consensus on the trough timing. This trough is
somewhat of a ridge runner, but won`t benefit from much capping
to keep skies clear; so convection will likely self limit given
skinny CAPE profiles. Still, moisture/temperatures will be
sufficient to allow for 1000+J/kg CAPE this afternoon and
triggering should be sufficient for thunderstorms. A few of
these storms could be heavy rainers with 1.5+inches of PWAT and
expected slow movement.
Friday is a different story. The ridge axis builds more over the
region with temperatures warming further. CAPE will likely build
beneath a capping inversion until a cold front sweeps through
the region. Shear will increase to around 30kts supporting more
favorable dynamics for organized convection. Shear coupled with
1500 to potentially 2500 J/kg CAPE will support at least
isolated stronger variety thunderstorms. SPC also has the
region under a Slight (15%) risk of severe thunderstorms given
heat, moisture, and a good triggering mechanism. While storms
are expected to be moving, some locations that have received
heavy rainfall may be susceptible to flooding. This will be
especially true for areas where roads have washed out.
KEY MESSAGE 3: Global deterministic and ensemble guidance is coming
into better agreement depicting a sharp cold front moving across the
region Sunday afternoon and evening. There will likely be some
discrepancies in subsequent model runs on when exactly the front is
expected to move through but there should be some decent instability
in place. Thunderstorms appear to be a good bet along the frontal
boundary as we will see daytime temperatures soar into the upper 80s
with dewpoints in the the 60s. Even if the front is delayed and
comes through overnight, elevated instability would still be present
and produce scattered to numerous thunderstorms. The latest machine
learning algorithms are showing the potential for some strong to
severe storms on Sunday but the timing of the front will be the key
to whether we see generic thunderstorms or those of the stronger
caliber.
Following the frontal passage, temperatures appear to drop back
closer to seasonal normals through the first half of next week. We
will be under the influence of a weak upper level trough that will
shunt the warmer air to the south while we see temperatures in the
70s and lower dewpoints than what we have seen as of late. However,
with the influence of an upper level trough and a pocket of cold air
aloft, a few diurnally driven showers and possibly a thunderstorm or
two cannot be ruled out each day. It doesn`t appear like any day
will be a wash-out by any means but some passing showers/storms will
remain a possibility each day.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Through 06Z Friday...Mid-level clouds are building in the wake of the
precipitation which has surprisingly helped stunt the potential for
fog development this morning. We will continue to see some rain
showers move across the region through 9Z with localized MVFR
visibilities possible within any showers. Ceilings will slowly drop
from 3000-5000 ft to 1000- 3000 ft between now and 12Z with a quick
improvement to high VFR by mid-morning. Additional showers and
thunderstorms are expected again this afternoon but will likely be
less widespread than those observed on Wednesday. Still, MVFR with
some very localized IFR visibilities could see seen with these
showers between 18Z and 00Z. Winds will be light from the west today
and become light and variable overnight.
Outlook...
Friday: VFR. Chance SHRA, Chance TSRA.
Friday Night: VFR. Definite SHRA, Chance TSRA.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. Chance SHRA, Chance TSRA.
Sunday Night: MVFR/IFR conditions possible. Chance SHRA.
Monday: Mainly VFR, with local MVFR possible. Slight chance SHRA.
&&
.CLIMATE...
Record High Temperatures:
June 12:
KBTV: 94/2017
KMPV: 88/2017
KMSS: 89/2005
Record High Minimum Temperatures:
June 11:
KBTV: 71/2017
June 12:
KBTV: 71/2017
KPBG: 67/2017
KSLK: 62/1996
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Heat Advisory from noon to 8 PM EDT Friday for VTZ001-002-005-
009-011-021.
Heat Advisory from noon today to 8 PM EDT this evening for
VTZ021.
NY...Heat Advisory from noon to 8 PM EDT Friday for NYZ028-035.
&&
$$
WHAT HAS CHANGED...Boyd
DISCUSSION...Boyd/Clay
AVIATION...Clay
CLIMATE...NWS BTV
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