560
FXUS61 KBTV 301733
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
133 PM EDT Sun Jun 30 2024

.SYNOPSIS...
Humid air ahead of a cold front will help supply enough fuel
for scattered morning thunderstorms. Some storms may be capable
of a few strong to locally severe wind gusts and flash
flooding. Chances of thunderstorms will decrease during the
afternoon as drier air begins to enter the North Country, and
precipitation chances will diminish tonight. Quieter weather is
expected for the upcoming week with seasonable warmth and mostly
rain-free conditions.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 124 PM EDT Sunday...Severe Thunderstorm Watch has been
issued for Essex, Caledonia, Orange, and Windsor Counties in
eastern VT until 8 PM.

Previous discussion...Biggest change with this update was to
temperatures. With ample sunshine, they`ve soared well into the
80s across much of VT, while NY spots are in the mid/upper 70s.
This is already above previously forecasted highs by 3-5
degrees, and have increased maximum temperatures for this
afternoon accordingly. Otherwise, the rest of the forecast
remains in good shape. We continue to see isolated to scattered
convection popping up along the pre-frontal trough, with the
bulk of the activity having been in the northern tier of
counties along the international border. Storms have not been
overly impressive so far, with updrafts getting sheared apart
before being able to gain much appreciable height. We will
continue to monitor closely, but so far the main threat has been
torrential rainfall; saw one rain gauge near Franklin, VT that
recorded nearly an inch in less than 30 minutes. Any
strong/severe storms would be capable of producing damaging
winds, as evidenced by strong cells that have been crossing
southern NY over the past couple of hours. Please remain weather
aware today, especially if you have outdoor plans.

A strong and complex frontal system will progress through the
northeastern US today. At the moment, we are in the warm sector
with ample heat and humidity, but because of the nocturnal
timing, instability is pretty low, especially in Vermont. In
northern New York, particularly in St. Lawrence and Franklin
counties, there is notably higher instability. This environment
should support thunderstorm development in the pre- dawn hours
as outflow from a cluster of showers in Ontario approaches,
providing necessary lift to grow existing showers, which are
being hampered by mid- level dry air. Given ample effective
shear and downdraft CAPE, organized thunderstorms will be
capable of isolated, damaging wind gusts, so we will be focused
on the morning convection over the northern counties of our
region as it moves across northern New York and Vermont.

Following this, there will be one more opening for impactful
weather associated with a pre-frontal trough, between 8 AM and
about 1 PM. There will likely be at least some sunny breaks in
the sky, allowing for temperatures to warm into the low 80s
across much of Vermont to boost instability. Coverage of
thunderstorms remains questionable given the drying aloft, but
any cells will also be capable of damaging wind gusts with
similar parameters given high deep layer shear and DCAPE.
Generally the threat will shift southeastward during this time
frame.

Then this evening we will see winds back to the northwest,
supporting lowering humidity following some scattered showers
along and just behind the cold frontal passage. Low temperatures
should be about seasonable in the upper 40s to near 60. Dry
weather is expected tomorrow. With continued cold air advection
and the related northerly breezes, temperatures tomorrow will
end up actually a little below normal, mainly in the low to mid
70s.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
As of 324 AM EDT Sunday...Surface high pressure building into the
region with a cooler, drier airmass with low temperatures in the
40s/L-M50s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
As of 324 AM EDT Sunday...Really no changes from yesterday`s
perspective...High pressure still in control on Tuesday with
moderating temperatures to near or slightly above seasonable levels
with highs in the U70s-L80s. Tuesday night will feature upper ridge
axis across the NE and dampening with the approach of a northern
stream shortwave with the surface high shifting SE for the
development of a return SSW flow and temperatures back into the
M50s-L/M60s.

Northern stream shortwave shifts east across southern Canada which
will dampen further the heat ridge across the southern CONUS. A warm
front traverses the area Wed with increased heat/humidity but likely
decent amount of clouds which may limit instability. Pre-frontal
trof may try to move during or shortly after peak heating so can`t
rule out showers and t-storms late Wed then front Wed eve especially
in northern NY possibly holding off in VT until around/after any
firework celebrations but stay tuned. as there are some firework
celebrations Wed eve. Highs in the upper 70s-M80s with dewpoints
back AOA 60F.

Upper level shortwave rotates east across southern Ontario/Quebec
thus the cold front slowly moves across CWA but appears to wash out
across the area. Therefore showers overnight Wed night with a
leftover morning shower possible on the 4th. Otherwise, despite a
lingering boundary there appears to be lack of any lift or
instability and should be mainly dry or only a shower for
Independence Day festivities with temperatures in the U70s-M80s.

Another northern stream shortwave/trof moving across the upper
Mississippi Rvr Vly Friday lifts ENE across the northern Great Lakes
and weakens Friday night and takes a similar path across SE Canada
Saturday. Weak low pressure associated with it will follow suit but
the lingering boundary will attempt to lift across our area as a
warm front Friday night-Saturday for some shower activity but not a
repeat of yesterday. Also right now, I`m leaning toward mainly
dry for Friday.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Through 18Z Monday...Main concern through 00z Monday will be
scattered thunderstorms, mainly at KMPV and KRUT. IFR will be
possible should a thunderstorm move over any terminal, along
with gusty winds, heavy rain, and small hail. Otherwise, VFR
conditions will persist through 02z Mon, along with scattered
showers. After 02z, ceilings will lower to 1200-2800 ft, with
IFR potentially possible at KSLK, with showers gradually winding
down overnight. Ceilings improve to VFR by 13z, with skies
clearing from north to south through the remainder of the
period. A cold front shifting through the region from north to
south will allow south/southeast winds to turn to the west and
eventually northwest by 00z Monday. Winds remain gusty to 20 kt
through 00z as well, then remaining 5-10 kt overnight into
Monday morning.


Outlook...

Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. Slight chance SHRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, Slight chance TSRA.
Independence Day: Mainly VFR, with local MVFR possible. Slight
chance SHRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR. Slight chance SHRA, Slight chance TSRA.

&&

.HYDROLOGY...
The threat for localized heavy downpours and isolated flash flooding
continues across our region through midday. We`ve generally
seen between 0.75" and 1.5" of rain over the last 24 hours.
Sharp river rises of the East Branch of the Passumpsic in East
Haven and the Lamoille River in Johnson occurred overnight,
indicative of hydrophobic soils. Therefore, scattered heavy
showers and thunderstorms this morning will be capable of flash
flooding in portions of northern Vermont today.

&&

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

&&

$$
SYNOPSIS...Kutikoff
NEAR TERM...Hastings/Kutikoff
SHORT TERM...SLW
LONG TERM...SLW
AVIATION...Hastings
HYDROLOGY...Clay/Kutikoff