-- Discussion containing changed information from previous version are highlighted. --
061
FXUS61 KBTV 180601
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
201 AM EDT Tue Jun 18 2024

.SYNOPSIS...
A period of dangerously high heat starts on Tuesday and will
persist into Thursday. Highs will reach well into the 90s each
day, and overnight temperatures will remain muggy and
uncomfortable. Please be sure to take appropriate precautions to
avoid heat stress through the remainder of this week. Although
an isolated thunderstorm can`t be ruled out Tuesday or
Wednesday, our next best chance for rain arrives late Thursday
into Friday with a cold frontal passage.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
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As of 148 AM EDT Tuesday...Light southerly winds continue
tonight resulting in a slower cool down. It`s still 79 degrees
at nearly 2AM which doesn`t bode well for this morning`s
starting temperatures and subsequent warm-up through the
afternoon. Adjusted overnight lows to cool more slowly in
broader valleys, but will wait until the next update to fine
tune the thermal trend after daybreak. Otherwise, we could see
some thunderstorms firing off of lake breeze tomorrow,
especially on the western shore where lake breeze would be
pushing upslope and up-shear allowing for increased
convergence. If storms do form, they would lower temperatures
mainly over the Champlain Valley, but at the cost of an increase
in damaging wind potential - CAPE/DCAPE values are projected to
far exceed the typical range for the North Country. Heat is
still the primary concern despite any localized cool downs from
a shower or outflow from a thunderstorm.

Previous discussion below:
The forecast remains on track, with a period of dangerously
warm temperatures expected to start Tuesday.

Ample sunshine across much of the region has allowed
temperatures to warm into the upper 70s to mid 80s in most
locations this afternoon. Dewpoints are already creeping up as
well; readings in the mid and upper 60s are fairly common.
Moisture will continue to increase tonight, and the result will
be a muggy overnight, especially in the St Lawrence and
Champlain Valleys, where lows will only drop to around 70F. Low
to mid 60s are expected elsewhere.

Things really start to heat up on Tuesday, with 925mb
temperatures approaching 25-27C. The question is how much cloud
cover there will be through the day. A weak shortwave currently
moving into western NY is producing some convection this
afternoon. This feature will continue to slowly push eastward
tonight and Tuesday. While current expectations are that the
convective activity will wane as it approaches the North
Country, there very well could be debris clouds passing overhead
during the morning and early afternoon hours. While it`s hard
to discern just how extensive this cloud cover may be, there are
some indications that it could be thick enough to limit warming
just a touch tomorrow. Have therefore lowered the maximum
temperature forecast just a tad, though really just by a degree
or two - not enough to make an appreciable difference. With
dewpoints to approach or even exceed 70F, still anticipate
dangerously high heat index values in the mid/upper 90s to
around 100F. Even if we do get more clouds than expected, it
will still be very warm tomorrow, so please make sure to follow
the proper heat precautions.

Otherwise, while a stray thunderstorm or two can`t be totally
ruled out given the abundance of moisture and instability that
will be available, continue to believe that tomorrow will be
dry. Tuesday night will be even warmer and more uncomfortable
than tonight; lows will likely remain in the 70s in the wider
valleys, with upper 60s in higher elevations.
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&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
As of 333 PM EDT Monday...A prolonged period of dangerous heat
is expected to continue across the region through Thursday. A
strong upper level ridge will continue to amplify as it shifts
towards the region, with 925mb temperatures reaching or
exceeding +25C. The current forecast shows high temperatures
soaring into the 90s for Wednesday and Thursday, with dewpoints
in the upper 60s to low 70s leading to heat indices in the mid
90s to low 100s. There is a non- zero chance for precipitation
throughout the period given the abundant moisture and hot
temperatures. In addition to the hot daytime temperatures,
overnight low temperatures will also remain warm with mist
places struggling to drop below 70s which will add to the
cumulative impacts of the heat. Experimental NWS HeatRisk
highlights the threat well, showing major to extreme risk of
heat related impacts for the middle of this week. Be sure to
practice heat safety by staying hydrated, avoiding strenuous
outdoor activity and checking up on your family, friends,
neighbors, and those most vulnerable to heat.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 333 PM EDT Monday...The ridge begins to flatten out and a
frontal boundary will start to drop through the region Thursday
night into Friday, providing some relief to the heat. While the
overall forcing and moisture is rather lackluster, instability
will be quite high given the heat and humidity which will may
allow for showers and thunderstorms to develop along the front.
Temperatures during the day on Friday will be cooler but still
be on the warm side for this time of year, with high
temperatures in the 80s to lower 60s across southern Vermont
depending on how quickly the front passes through. Temperatures
heading into the weekend will remain on the warmer side of
normal heading into the weekend, with more chances for showers
as we head into the weekend.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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Through 06Z Wednesday...VFR conditions are expected overnight
except for some moderate fog potential at SLK which is showing
near saturated conditions and decreases below 10SM already at
the VIS sensor. Result was to include some MVFR conditions 7-11Z
with a lower potential of worse than MVFR mainly if mist can
consolidate into a 100ft cloud layer. Otherwise, included some
convective clouds for the 17-22Z period with VCSH at PBG. Best
chances of thunderstorms will be along the west shore of Lake
Champlain as lake breeze results in surface convergence. Should
TS form, gusts will likely be strong given the expected heat.
Tonight, rather benign conditions return.

Outlook...

Wednesday: VFR. Slight chance SHRA, Slight chance TSRA.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. Chance SHRA, Chance TSRA.
Thursday Night: VFR. Chance SHRA, Slight chance TSRA.
Friday: VFR. Chance SHRA, Slight chance TSRA.
Friday Night: VFR. Slight chance SHRA.
Saturday: VFR. Chance SHRA, Slight chance TSRA.
-- End Changed Discussion --

&&

.CLIMATE...
Hot temperatures will result in values near records by the
middle of next week. Below are some of the records under threat
of being broken.

Record High Temperatures:

June 18:
KBTV: 97/1994 Forecast 96
KMPV: 93/1994 Forecast 92
KPBG: 94/1994 Forecast 92
KMSS: 97/1994 Forecast 94
KSLK: 94/1907 Forecast 91

June 19:
KBTV: 100/1995 Forecast 97
KMPV: 95/1995 Forecast 93
KPBG: 93/2001 Forecast 94
KMSS: 94/1955 Forecast 93
KSLK: 93/1994 Forecast 91

June 20:
KBTV: 95/2012 Forecast 96
KMPV: 90/2020 Forecast 92
KPBG: 94/1964 Forecast 92
KMSS: 92/2012 Forecast 91
KSLK: 92/1995 Forecast 90


Record High Minimum Temperatures:

June 19:
KPBG: 70/1949 Forecast 69

June 20:
KPBG: 70/1953 Forecast 72
KSLK: 68/2012 Forecast 66

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
VT...Heat Advisory from noon today to 8 PM EDT Thursday for
     VTZ001>011-016>021.
NY...Heat Advisory from noon today to 8 PM EDT Thursday for
     NYZ026>031-034-035-087.
-- End Changed Discussion --

&&

$$
SYNOPSIS...Hastings
NEAR TERM...Boyd/Hastings/Taber
SHORT TERM...Kremer
LONG TERM...Kremer
AVIATION...Boyd/Neiles
CLIMATE...Team BTV