000
FXUS61 KBTV 301943
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
343 PM EDT Tue Jun 30 2020

.SYNOPSIS...
Continued scattered showers and thunderstorms are possible again
on Wednesday as upper level low remains overhead. Hot weather is
expected on Wednesday with highs in the upper 80s to low 90s
before a weak cold front brings slightly cooler readings for the
upcoming holiday weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 340 PM EDT Tuesday...Increasing convective coverage this
afternoon will give way to largely beneficial rains across most of
VT and into areas of eastern NY. The heavier of these storms are
putting down around 1-1.5" of rain in an hour or so, therefore
continue to think the threat for isolated flooding may be possible
if locations see training storms. This threat will be highly
localized, and given recent dryness, likely minimal in impact
resulting in ponding of water in poor drainage areas along with
minor washouts possible. Tonight, expect low clouds and fog to
return as has happened the last couple nights with lows in the
around 60 mountains/mid 60s valleys. As upper level circulation
remains overhead again on Wednesday, anticipate similar evolution to
the day as today. Convective threat looks maybe slightly more
organized for Wednesday as temperatures warm into the upper 70s to
around 80, with CAPE values around 700-1000 J/kg and 15- 25kt of bulk
shear creeps into our western NY zones. Given better lapse rates and
layer deep shear, in addition to the threat for heavy rainfall,
briefly gusty winds may be possible as well. The nearly stationary
area of low pressure off the MA coastline will finally begin to
drift southward Wednesday night and we should finally see the return
of drier weather Wednesday night heading into Thursday. Nearly
similar low temps in the upper 50s/low 60s are expected Wednesday
night.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 340 PM EDT Tuesday...Hot weather expected Thursday as a
departing upper level system will allow for a ridge axis to shift
into our region. Warm air advection and mostly clear skies will
drive temperatures into the mid to upper 80s across the high terrain
and near 90 across the valleys. The influence of the ridge will
cause warming aloft, making conditions less favorable for showers
and thunderstorms. Thus, mostly dry conditions are expected Thursday
afternoon, though a few showers and storms could spark along the
mountain ridges mid-day. Looking at dewpoints, values should remain
in the low to mid 60s, which will bring heat indices to 92-93 in the
Champlain and St. Lawrence Valleys - just below advisory level.
Still, for prolonged activity, taking a few precautions and knowing
the signs of heat exhaustion is always beneficial.

The better focus for precipitation will be with a backdoor cold
front late into evening into the overnight hours. Upstream
instability and shear should allow storms to develop over southern
Quebec Province, aided by a jet streak aloft. The question becomes
whether that convection can sustain itself during the evening hours
as it heads into our environment of less shear, waning instability,
and lack of inflow ahead of the convection. The front will slowly
sag south and may not be clear of the area by Friday morning. Thus,
another warm night with upper 50s to mid 60s will be in store.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 340 PM EDT Tuesday...Still looking at some scattered convection
across the Adirondacks and south-central Vermont as a weak cold
front slowly sags south on Friday. Then, large scale ridging off to
the west tries to nose into our region, but will flatten as it comes
in. This will maintain northwest flow aloft that will allow weak,
embedded shortwaves to cross the area into the new week. With above
normal temperatures (mid to upper 80s) and dewpoints in the lower
60s, diurnally driven showers and thunderstorms will be possible
each day.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
Through 18Z Wednesday...Mix of MVFR/VFR out there this
afternoon. Similar to yesterday, daytime convection will bring
chances for heavy rainfall and brief IFR visibilities across the
airspace this afternoon. Have included VCTS in all VT TAF sites
as timing of exact airport impact is difficult given cellular
nature of storms today. Tonight, expect aviation conditions to
deteriorate back down to MVFR/IFR once again as low level
moisture remains socked in place. Ceilings/visibilities will
lift towards 13/14z similar to today. Winds will be out of the
N/NW around 5-15kt this afternoon, trending light overnight
before increasing around 5-15kt again tomorrow.


Outlook...

Wednesday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Thursday: VFR. Slight chance SHRA, Slight chance TSRA.
Thursday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Friday: Mainly VFR, with areas MVFR possible. Slight chance SHRA.
Friday Night: VFR. Slight chance SHRA.
Independence Day: VFR. Slight chance SHRA.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. Slight chance SHRA.

&&

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

&&

$$
SYNOPSIS...LaRocca
NEAR TERM...LaRocca
SHORT TERM...Haynes
LONG TERM...Haynes
AVIATION...LaRocca