275
FXUS61 KBTV 060751
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
351 AM EDT Sat Jul 6 2024

.SYNOPSIS...
Numerous showers and thunderstorms will roll through the forecast
area this morning, with more hit or miss activity this afternoon
before dissipating after sunset. Drier days are forecast for Sunday
and Monday although remaining humid at the ground and warm. Another
round of showers and thunderstorms likely late Tuesday into
Wednesday along a cold front passage. Slightly cooler and less humid
air returns midweek.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 351 AM EDT Saturday...Showers and thunderstorms continue to
shift across northern New York this morning along a stalled frontal
boundary draped through the region. This activity will continue to
move eastward through mid- morning, affecting the Champlain Valley
around sunrise with brief heavy rain likely, but no strong storms.
Meanwhile to our south, convection is exploding over eastern PA
along a surface trough extending southward from the NY Capitol
region into the central Appalachians, and the latest CAMs show this
activity riding northward into western MA and southern/central VT
from about 9 AM to noon before shifting east of the CT River Valley.
Still not expecting anything more than some heavy rain from these
storms with hourly amounts generally below 1".

After all the morning convection passes, we should see breaks of
sunshine develop and with surface dewpoints still well into the
upper 60s to lower 70s instability will grow with progged SBCAPE`s
in the 1000-1500 J/kg range. A weak cold front to our west and some
embedded shortwave energy riding northeastward ahead of the parent
upper trough over the Great Lakes should provide the necessary lift
to spark some additional showers and thunderstorms in the afternoon,
but should be fairly widely scattered. Some storms could become
strong, though as the previous forecaster mentioned, the presence of
some mid-level dry air and 50-60kts of 0-6km shear may hamper
updraft development. Certainly areas to watch for isolated flash
flooding will be where the greatest rainfall footprints are from the
morning convection, which will likely be across Rutland, Windsor,
and Orange counties.

Convection generally dissipates after sunset but with the frontal
passage not expected until after midnight, the warm and humid
airmass will likely support some isolated showers and perhaps some
embedded thunder through the first half of the overnight. Drier
conditions generally follow for Sunday though a weak boundary north
of the border may help to spark some isolated showers across border
towns. Not enough to cancel any outdoor plans for sure, but temps
will once again be rising into the mid/upper 80s and dewpoints
remain in the 60s producing a moderate heat risk for some VT locales.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
As of 351 AM EDT Saturday...Sunday night should be cooler than of
late, with mostly clear skies and light winds promoting good
radiational cooling. Some of the colder hollows could see lows in
the lower 50s with upper 50s to low 60s for many locations. Warmest
spots would once again be across the urban centers of the Champlain
valley with lows in the mid 60s. Surface high pressure moves
overhead on Monday, which should prove to be a decent day for
outdoor activities with comfortable humidity. Temperatures will once
again peak in the mid 80s to near 90, but with mixing up to
850-800mb, lower dew points should be mixed down to the surface so
expect plentiful sunshine with breezy southwest winds helping to
make being outdoors rather pleasant for the North Country in mid
July. By Monday night, winds will shift to the south as an upper
level disturbance approaches from the Great Lake with overnight lows
generally in the 60s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 351 AM EDT Saturday...Upper ridging starts to break down on
Tuesday as a positively tilted upper level trough approaches from
the Great Lakes. As such, shower and thunderstorm chances do return
on Tuesday. NAEFS ensemble situational awareness table shows PWATs
and IVT rising to over 90th percentile for our region later Tuesday
into Wednesday, so multiple rounds of heavy rainfall is certainly
possible with a slow-moving cold front nearby providing the focus
for scattered to numerous thunderstorms. Looking upstream, the
anomalous PWAT plume appears to have its origins in the Gulf of
Mexico. The orientation of the approaching upper trough does allow
for the possibility of TC Beryl- related moisture to stream towards
the Northeast. PWATs rise to around 2 inches on Tuesday with some
deterministic guidance even showing upwards of 2.3 to 2.5 inches.
For reference, the daily max of climatology for Albany, NY upper air
site around mid July is around 2.1 inches. Fortunately for our area,
the consensus of guidance shunts the plume of richest PWATs south of
our area later Tuesday into early Wednesday. There are indications
that the unusually moist air mass could coincide with the better
dynamics for stronger storms that would further enhance the
rainfall, but mid- range guidance still unsurprisingly differ on the
timing of the surface cold front. Right now, WPC has continued to
highlight a marginal risk for excessive rainfall for Day 4 (Tuesday
into Tuesday night) across the entire CWA but not Day 5 (Wednesday
into Wednesday night). Those with outdoor plans middle of next week
are advised to stay up to date with the latest forecast.

Additionally, if drier weather were to prevail, parts of the
Champlain valley and Connecticut valley could see heat index values
rise into the lower and mid 90s. WPC heat risk does highlight
potential for widespread moderate heat-related impacts for Tuesday
so the temperature trends are worth monitoring as well in addition
to heavy rainfall and thunderstorms. Cold front should finally clear
the region later Wednesday into Thursday, leading to at least a
couple of days with more seasonable temperatures (upper 70s to mid
80s) and comfortable humidity (dew points in the 50s) for mid July
standards. Having said that, the aforementioned plume of tropical
enhanced moisture continues to linger across the Mid Atlantic states
into Southern New England. By Friday, a warm front may be lifting
northwards again and we might once again get into the more humid if
not oppressive air mass. Stay tuned.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday...VFR conditions are expected to generally
prevail through the overnight hours with showers and embedded
thunder affecting KMSS and KSLK through 12Z which could briefly
reduce cigs to MVFR and vsby IFR. To the east, there is a
lesser chance of isolated showers, and ceilings may lower to
MVFR and possible IFR at times at KRUT, KMPV, and KEFK.
Confidence is very low at fog occurring based on current
conditions so have removed that from the previous forecast.
After 12Z rounds of showers are likely with thunderstorms
possible with the highest confidence of prevailing rain being
from 13-18Z for VT terminals, then VCSH for the afternoon as
confidence is much lower when and where convection will occur.
Anything that does develop will diminish after 00Z, with skies
trending SCT thereafter.

Outlook...

Sunday: VFR. NO SIG WX.
Sunday Night: VFR. Patchy BR.
Monday: VFR. NO SIG WX.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. Chance SHRA, Chance TSRA.
Tuesday Night: MVFR/IFR conditions possible. Likely SHRA.
Wednesday: Mainly MVFR, with local IFR possible. Likely SHRA.

&&

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

&&

$$
SYNOPSIS...Lahiff
NEAR TERM...Lahiff
SHORT TERM...Chai
LONG TERM...Chai
AVIATION...Lahiff