382
FXUS61 KBTV 291928
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
328 PM EDT Mon Jun 29 2026
.WHAT HAS CHANGED...
As of 325 PM EDT Monday...
Excessive Heat Watch has been issued for the Champlain Valley and
Eastern Windsor County in Vermont from 16Z Weds through 23Z Friday
for daily heat index values near 105 degrees.
&&
.KEY MESSAGES...
As of 325 PM EDT Monday...
1. Major to localized extreme heat risk expected Wednesday thru
Friday with heat index values near 105 degrees possible in the
Champlain Valley/Eastern Windsor and 95 to 100 elsewhere.
2. Daily chances for showers and thunderstorms increase on
Tuesday and continue through Thursday, some localized strong to
severe storms possible.
3. Dangerously hot and humid conditions will linger into the
holiday weekend along with daily chances of showers and
thunderstorms.
&&
.DISCUSSION...
As of 325 PM EDT Monday...
KEY MESSAGE 1: A long and dangerous heat wave is expected to impact the
fa from Weds into the upcoming holiday weekend, as a strong
mid/upper lvl heat ridge builds acrs the central Appalachian
Mountains. Progged 925mb temps are expected to be in the 26-29C range
for Weds and Thurs, which is 99th-100th percentile for our cwa,
indicating the significance of this upcoming heat wave. In addition,
2m dwpts wl continue to climb Tues thru Thurs with many areas seeing
values in the 68-75F range, during max heating. This wl create heat
index values around 105F in the watch area and 95 to 100F outside
the watch, where eventually heat advisories wl likely be needed. The
warmest day continues to be Thursday acrs our cwa with high temps in
the lower 90s mtns to upper 90s warmer valleys. A few record high
temps are likely to be broken on during this heat wave. The boundary
layer moisture wl result in very muggy conditions overnight with
lows upper 60s to upper 70s most nights.
KEY MESSAGE 2: Very challenging fcst with regards to thunderstorm
potential and intensity on Tues and Weds, given large spread in
potential solutions from CAMS. SPC has upgraded most of our cwa to
slight risk (2 out of 5) for severe with 15% wind and 5% tornado
prob.
Mid/upper lvl ridge over the Ohio Valley/Great Lakes wl be expanding
toward our cwa, while convectively induced vorts wl be ejecting from
northern Rockies trof acrs southern Canada and diving southeast acrs
the Mid Atlantic/NE CONUS Tues thru Thurs. On Tues the heat/humidity
and associated instability wl be expanding northward toward our cwa,
creating a potential boundary for convection to follow. The best
instability looks to be located acrs our western and central cwa,
with less over the NEK. HREF mean CAPE shows values near 300 J/kg
over the NEK, 1000 J/kg CPV and 1500 J/kg over the SLV on Tues aftn
with 0 to 6 km shear of 40 to 50 knots. Guidance spread is rather
large on placement of convection on Tuesday with some CAMS having
the convection over central NY, while others have it over central
Maine. However, the gradient is progged to be acrs our cwa and that
is typically a place where convection likes to travel. The HRRR/RRFS
and RAP indicate a potential busy day for convection, while
NAM3KM/ARW and WRF NSSL is much less robust with convection. An EML
was evident in some guidance as warm dry air in the 700-500mb layer
was progged to advect off the southern Rockies and move around the
periphery of ridge and toward the northeast CONUS late Tues into
Weds. If convection does occur, given available instability/shear
and pw`s surging above 1.50", gusty winds, hail and heavy down pours
are possible. Have not placed enhanced wording in grids yet, given
the uncertainty in timing/placement of convection for Tues. Similar
type of scenario is expected on Weds and Thurs with daily potential
for strong to locally severe thunderstorms. If you have outdoor
plans, please keep an eye to the sky and be ready to seek shelter if
threatening weather approaches your location this week.
KEY MESSAGE 3: Friday is likely to be our third day in a row with at
least heat advisory conditions in place as maximum temperatures
reach the upper 80s to mid 90s. Have a chance of showers and
thunderstorms mentioned on Friday as a weak cold front will drop
into our area from Canada. This front will then remain draped
somewhere across or very near to our forecast area through the
weekend. This means there will be additional chances for showers and
thunderstorms on both Saturday and Sunday, but it may not be as hot
as previous days since clouds and precipitation can help damper the
afternoon maximum temperatures. Each day should be a few degrees
cooler than the previous day. Minimum temperatures remaining in the
70s in some locations will make it tough to cool off and
accumulating warm days will take its toll.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
Through 18Z Tuesday...Through 18Z Tuesday... Very quiet aviation
forecast period over the next 24 hours at all 7 terminals. Winds
will be light and skies mostly clear with only FEW to SCT mid to
high clouds at times. PBG has developed a light lake breeze this
afternoon with winds out of the east off the lake which will become
light to calm overnight. Do not believe we will reach crossover
temperatures overnight, so left mention of fog out of the forecast
at this time.
Outlook...
Tuesday Night: VFR. Chance SHRA, Chance TSRA.
Wednesday: VFR. Chance SHRA, Chance TSRA.
Wednesday Night: VFR. Chance TSRA, Slight chance SHRA.
Thursday: VFR. Slight chance SHRA, Slight chance TSRA.
Thursday Night: VFR. Chance SHRA, Chance TSRA.
Friday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight
chance TSRA.
Friday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Independence Day: Mainly VFR, with local MVFR possible. Chance
SHRA, Chance TSRA.
&&
.CLIMATE...
Extreme heat and humidity is possible later this week,
especially on Wednesday and Thursday, which could lead to some
daily records. Below are the current daily high and low
temperature records in jeopardy at our area climate sites.
Record High Temperatures:
June 30:
KBTV: 93/2018
July 1:
KBTV: 96/2018
KMPV: 92/2018
KPBG: 94/1968
KMSS: 94/2018
July 2:
KBTV: 97/2018
KMPV: 90/2018
KMSS: 94/2018
July 3:
KMPV: 91/2002
Record High Minimum Temperatures:
July 1:
KBTV: 76/2018
KPBG: 73/1971
KSLK: 69/2018
July 2:
KPBG: 77/2002
KSLK: 68/2002
July 3:
KBTV: 76/1911
KPBG: 73/2002
July 4:
KPBG: 71/1973
KSLK: 67/1952
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Extreme Heat Watch from Wednesday afternoon through Friday
evening for VTZ001-002-005-009-011-021.
NY...Extreme Heat Watch from Wednesday afternoon through Friday
evening for NYZ028-035.
&&
$$
WHAT HAS CHANGED...Taber
DISCUSSION...Taber/Neiles
AVIATION...Neiles
CLIMATE...NWS BTV
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