334
FXUS61 KBTV 070047
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
847 PM EDT Thu Jun 6 2024

.SYNOPSIS...
Moderate to locally heavy rain showers are expected this evening
as a front moves through. The rest of the week into early next
week will feature cool temperatures and shower chances most
days as an upper-level low stalls overhead.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 736 PM EDT Thursday...Forecast is largely on track. A line
of showers with embedded downpours and isolated thunder
associated with the occluded front is approaching the Champlain
Valley. Isolated gusts of up to 40 mph are possible. Forecast
remains largely on track. When thunder roars, go indoors.

PREVIOUS DISCUSSION...A cold front will sweep through from west
to east this evening, with the frontal passage marked by a line
of moderate to locally heavy rain showers with some embedded
thunderstorms. Expect the heavy showers to move through northern
NY between 3 PM and 7 PM, moving into the Champlain Valley
between 6 PM and 10 PM. During the evening hours, the rain
showers will become lighter as the line moves into eastern
Vermont. The main hazard this evening associated with the
showers/storms will just be locally heavy rainfall, with
precipitable water values analyzed between 1.5 and 1.8 inches in
northern NY and relatively deep warm cloud depths. Rainfall
amounts upstream have locally exceed 1.3 inches in places, but
most areas have picked up between a quarter and three quarters
of an inch. Storm total precipitation amounts for our forecast
area this evening range from 0.75 to 1.1 inch over northern NY
and into northwestern VT, then generally around a half inch for
eastern VT. We should be able to handle these amounts without
any real issues, although we could see some ponding of water in
poor drainage areas. Will be watching hydro closely through the
evening.

Overnight tonight, showers will weaken and diminish in coverage.
We will see some patchy fog/mist form, especially over valleys
in eastern Vermont. Overnight lows will be in the low to upper
50s.

The core of a deep upper-level low will shift into southeastern
Ontario Friday.  As the low approaches our forecast area, mid-level
height falls, steepening lapse rates, and multiple shortwaves
rotating around the upper low will promote showery conditions.
Expect coverage and intensities of showers to increase through the
day along with increasing diurnal instability.  700 to 850 mb lapse
rates will peak around 7.5 to 8.5 deg C/km Friday midday/afternoon,
coincident with blossoming coverage of showers.  Between 100 and 500
J/kg SBCAPE will develop during the afternoon, highest over northern
and western counties (closest to the core of the low), thus expect
some isolated embedded thunderstorms within the showers.  Potential
for developing instability and thunderstorms will remain dependent
on any clearing in the clouds.  Even if we do see thunderstorms,
severe weather isn`t expected as the better shear will remain
displaced to the east of the best instability.  High temperatures
for Friday will be in the low to mid 70s for much of the area,
locally in the upper 70s to 80 in the Champlain and Connecticut
River Valleys. Showers will diminish in coverage Friday night with
the loss of diurnal instability.  Overnight lows will be in the 50s
for most areas, locally in the upper 40s in the Adirondacks.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 316 PM EDT Thursday...Overall, the weekend will be showery as
an upper level low will be in place to the north of the region.
However, the showers will be on and off so it will not be raining
the entire time, especially in the broad valleys. Diurnal heating
and cold temperatures aloft will cause scattered to numerous showers
to develop in the afternoons. Two shortwaves pivoting around this
low will pass through, one around Saturday morning and one late in
the day on Sunday into Sunday night. Very weak ridging will build in
Saturday night. Because of the cold air aloft, there will still be
daytime showers when the ridging is in place but they should be less
numerous than in the shortwaves. The shortwave Sunday night should
be able to keep some showers over the area at night, even without
the diurnal heating. There is the chance for an isolated
thunderstorm on Saturday or Sunday afternoon, but they would be non-
severe and a vast majority of the convective showers will contain no
thunder. Temperatures during this period will be slightly under
normal to around normal. Highs will be between 65-75 and lows will
be in the 50s and upper 40s.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 316 PM EDT Thursday...One final shortwave pivots through on
Monday and it will help increase the showers again during the day.
These showers look to be lighter and less widespread than over the
weekend and the chance of thunder looks lower as well. The upper
level low should mostly move out of the region Monday night and
ridging will begin to build in. A lingering shower is possible on
Tuesday but it looks like it should be mostly dry. A weak storm
system will move through the region later in the week but right now
it looks like it will relatively unimpactful. Temperatures should
trend above average by mid to late week but any significant heat
looks unlikely.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
Through 00Z Friday...Cold front continues to track east.
The tropical airmass is causing rain in a narrow band to produce
3/4SM to 2SM visibility and quick accumulations. Periodically,
there have been embedded gusts within the line, but the winds
are expected to weaken heading east. After 04z, shower activity
will shift east. Some LLWS is possible at KEFK and KMPV through
about 05z along the frontal axis with south winds around 35
knots at 2000 ft agl. As skies clear tonight and with recent
rain and very humid conditions, fog will be possible, but not
guaranteed due to 15 knot winds just off the surface. Beyond
10z or 11z fog should dissipate, with mainly south to southwest
winds across the region at 5 to 10 knots. Pop up showers and a
few storms will develop beyond 15z Friday.

Outlook...

Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Saturday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Sunday: Mainly VFR, with local MVFR possible. Likely SHRA, Slight
chance TSRA.
Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Monday: Mainly MVFR, with local IFR possible. Chance SHRA.
Monday Night: Mainly VFR, with areas MVFR possible. Slight chance
SHRA.
Tuesday: VFR. Slight chance SHRA.

&&

.CLIMATE...
Based on the current forecast, daily records are possible at
some climate sites.

Record daily precipitation is possible at Massena and
Plattsburgh today.

Record Precipitation:

June 6:
KPBG: 1.05/2008
KMSS: 1.09/1953

&&

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

&&

$$
SYNOPSIS...Duell
NEAR TERM...Chai/Duell
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Haynes
CLIMATE...Kutikoff/Kremer