-- Discussion containing changed information from previous version are highlighted. --
274
FXUS61 KBTV 132238
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
638 PM EDT Thu Jun 13 2024

.SYNOPSIS...
A cold front moving through the Great Lakes this afternoon will
bring a period of showers and possibly thunderstorms to our region
late tonight into Friday with localized stronger storms possible in
far southern Vermont early Friday afternoon. Cool and dry air
filters in for the weekend, but by Monday, warm and moist air will
shift back into the region. Temperatures warming into the upper 80s
to mid 90s is expected by the middle of next week. In conjunction
with high dewpoints and warm overnight conditions, heat impacts are
likely next week.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
As of 635 PM EDT Thursday...We had a few showers and one
thunderstorm develop over the higher terrain this afternoon but
these have been slowly weakening as the lack of forcing aloft is
stunting new convection. Further west, showers and thunderstorms
ahead of a cold front are marching eastward and will be here
during the late evening hours. Models continue to suggest these
storms will fizzle out over the North Country tonight but we
will continue to watch the storms closely as they move closer to
us. In the meantime, a stray shower cannot be ruled out through
sunset but mainly dry conditions are expected through the early
to mid evening hours.

Previous Discussion...The forecast remains on track for tonight
through Friday night with the main feature of interest being a cold
front currently moving through the Great Lakes region. CAMs have
been very consistent showing showers and embedded thunder associated
with the front won`t move into the St. Lawrence Valley until close
to midnight, then become fragmented and scattered as it moves
eastward through the remainder of the night into Friday morning.
With the loss of daytime heating and precip arrival time, along with
the best dynamics and cold pool shifting north of the region, the
threat for strong storms is low during the overnight hours despite a
strong low-level jet of 40-50kts moving across the region. As such,
gusty winds are likely the biggest threat which will continue up to
25 mph in the broader valleys overnight with the potential for brief
gusts greater than 35 mph along the frontal passage, mainly across
northern New York.

As the front shifts through Vermont during the daylight hours
Friday, a short window will exist in the early to mid-afternoon
hours for some stronger storms to develop across central and
southern zones where up to 1000 J/kg of CAPE and about 40-45 knots
of 0-6km shear may exist. As the previous forecaster mentioned, the
intensity of storms will be conditional on clearing, and SPC`s
depiction of a slight risk outlook south of our forecast area and a
marginal risk across Rutland and Windsor Counties of Vermont
continues to be reasonable. Any activity that does develop will wane
after sunset with the loss of surface heating and the front shifting
away from the region, and a quiet and cool night is on tap with lows
falling into the 40s and 50s.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
As of 326 PM EDT Thursday...The weekend weather will be gorgeous,
featuring highs in the 60s and 70s, and low humidity. There will
also be abundant sunshine and relatively light winds. Clear skies
and calm winds overnight will allow temperatures to drop quickly.
Lows Saturday night will mostly be in the 40s, but temperatures
should reach the 30s in the coldest hollows. Enjoy the cooler
weather while it lasts because significant heat will build in next
week.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 326 PM EDT Thursday...The first major heat event of the year
looks to occur next week, starting Tuesday and continuing for the
rest of the week. High temperatures above 90 degrees and increasing
humidity will likely cause apparent temperatures to be well in the
90s, particularly in the broad valleys. The region will be on the
northern periphery of an unusually strong ridge. Some model guidance
brings the center of it to 600 dm at 500 mb. Southwest flow will
prevent any cooling marine impacts from the Atlantic and increased
humidity will help lows stay elevated overnight. Temperatures in the
valleys will likely not fall out of the 70s Tuesday night onward,
preventing much overnight relief from the heat. While there is high
confidence of very warm temperatures, the exact magnitude of the
heat is still uncertain. It looks like there will be a couple of
shortwaves that will ride along the top of the ridge. With
sufficient instability from the airmass, it would not take much to
initiate some convection to keep afternoon temperatures a little
lower. Also, with westerly flow aloft from being on the northern
edge of the ridge, it is possible that debris from upstream
convection over the Great Lakes could stream into the area provide
some cloud cover. While this would limit high temperatures, it would
also increase overnight lows. However, despite these uncertainties,
there is high confidence in a significant heat event and the NBM
seems very reasonable in giving an 80-90 percent probability of
highs exceeding 90 in the broad valleys. However, the higher end
probabilities where it gives the Burlington area a 40-50 percent
chance of reaching 100 are likely unrealistic. Overall, this looks
to be a relatively long- duration significant heat event and it would
beneficial to take precautions early.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Through 18Z Friday...VFR conditions will prevail across the
region through 06Z before showers and embedded thunder roll
through with ceilings lowering to MVFR from around 09-15Z at
KMSS/KSLK/KEFK/KRUT. Visibility within the showers should
generally remain VFR with brief periods of MVFR possible. Gusty
winds will likely be the main concern through the period, with
SSW gusts up to 25kts at KMSS/KSLK/KBTV this afternoon through
much of the night, and the potential for a brief period of
25-35kts at KMSS around 06Z, and potentially KSLK around 08Z
along a frontal passage. LLWS is likely aloft at all terminals
through the overnight hours as a strong low level jet of 40-50kt
traverses the region.

Outlook...

Friday Night: VFR. Slight chance SHRA.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
Sunday Night: VFR. Slight chance SHRA.
Monday: Mainly VFR, with local MVFR possible. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Slight chance SHRA.

&&

.MARINE...
As of 326 PM EDT Thursday...A brief period of wind gusts up to
25 knots is expected across the broad lake waters tonight
prompting the issuance of a lake wind advisory. Waves will
likely build to 1 to 3 feet, and caution is urged for small
craft venturing out overnight.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Lahiff
NEAR TERM...Clay/Lahiff
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Lahiff
MARINE...Lahiff