FXUS61 KBTV 190743
Area Forecast Discussion
National Weather Service Burlington VT
343 AM EDT Mon Aug 19 2019
A broken line of showers and embedded thunderstorms will move
across the North Country this morning with brief heavy rainfall
and localized wind gusts to 30 mph. Additional afternoon showers
and storms are possible, mainly over eastern Vermont.
Temperatures will warm well into the 80s with a few readings
approaching 90 degrees in the Champlain and lower Connecticut
Valley. A dry and warm day is expected on Tuesday, followed by
more chances for showers and storms on Wednesday into Thursday.
.NEAR TERM /UNTIL 2 PM THIS AFTERNOON/...
As of 325 AM EDT Monday...Forecast challenge continues to be
convective chances and associated pops today. Water vapor shows
modest height falls across the eastern Great Lakes associated
with channeled 700 to 500mb vort, along with a ribbon of
enhanced mid level moisture. Regional mosaic radar indicates a
broken line of showers with embedded storms approaching the SLV
early this morning. Based on high res convective allowing
models, expect precip acrs dacks btwn 09z-11z, cpv 11z-13z,
central VT 13z-14z, and thru NEK/eastern VT by 16z. Laps shows
limited instability ahead of this line with CAPE values
generally <500 j/kg, but some elevated instability is present.
Thinking brief heavy rainfall and localized gust to 30 mph
possible within the heavier convective elements this morning.
Meanwhile, water vapor shows large area of subsidence/dry air
aloft building behind short wave energy, which should result in
clearing skies this aftn. This clearing will help warm temps
quickly into the 80s with a few locations near 90f in the
CPV/lower CT River Valley. The sfc heating will help create sfc
based cape values in the 1000 to 2000 j/kg across CPV and
portions of VT, while 0 to 6km shear is in the 35 to 40 knot
range. These parameters would support some organized convection,
however developing warm nose/cap around 800mb, along with deep
dry layer btwn 850 and 300mb with limited upper level forcing
will result in minimal activity this aftn/evening. Have mention
only schc/low chc (15% to 30%) pops from eastern Dacks into Vt
thru this aftn/evening.
Tonight into Tuesday...relatively quiet period of weather
anticipated with building heights and modest cap in place,
combined with dry air will limit threat for showers/storms.
Cannot completely rule out a stray shower/storm on Tues aftn
during peak heating/instability across the eastern Dacks or
higher trrn of Green Mtns. The best convergence will be
associated with lee side trof/lake breeze boundary interaction
on the west side of the CPV. 925mb to 850m thermal profiles are
slightly cooler on Tues with highs generally in the upper 70s
to mid 80s anticipated, with some drier dwpts/lower humidity
values as better mixing occurs during the aftn hours. Some areas
of patchy fog is likely tonight, with clearing skies and light
winds, especially as cross over values are reached in many
locations. Lows a little cooler than recent nights with readings
from the mid 40s slk to lower 60s CPV.
.SHORT TERM /2 PM THIS AFTERNOON THROUGH TUESDAY NIGHT/...
As of 303 PM EDT Sunday...Picture perfect late summer weather
expected for Tuesday with high pressure settling across the region.
Drier air will work southward from Canada behind Monday/Monday
night`s frontal passage. Thus expect plenty of sunshine, lower
dewpoints, and highs in the upper 70s to mid 80s. The dry weather
will continue into Tuesday night, though moisture will begin to
spread northward overnight as the flow turns to the southwest ahead
of a potent upper trough approaching from the west. A few showers
may move into southern Rutland and Windsor Counties late, but
overall expect any precipitation to hold off until Wednesday. Lows
will be in the upper 50s to mid 60s.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 303 PM EDT Sunday...Wednesday and Wednesday night are the focus
of the long term as a vigorous upper trough is expected to bring a
round of showers and thunderstorms to the region. However, still
uncertainty as to how things will play out since, as is usually the
case, parameters are not all quite optimally lined up. Moisture will
surge into the North Country during the day Wednesday, though how
much is in question. The GFS continues to show the highest PWATs
remaining to our south with a frontal boundary across coastal New
England, while the NAM indicate 1.5-1.75 inch PWATs streaming into
areas from the Champlain Valley eastward. This has implications on
instability, as does the 700-850mb warm layer indicated by the GFS.
In spite of increasing moisture, there does look to be quite a bit
of dry air to overcome aloft Wednesday afternoon as well. A
prefrontal trough will precede the cold front, which won`t arrive
until after peak daytime heating. However, this is a very dynamic
system, and 0-6km shear will be around 30kt. Have therefore gone
with likely PoPs for Wednesday evening, but subsequent shifts will
need to monitor for severe potential. Wednesday will be hot and
muggy as well with highs in the lower to mid 80s in many spots. The
front will push through Wednesday night, and precipitation will wind
down as a result. It`ll be one last uncomfortable sleeping night
with lows remaining in the 60s.
For Thursday onward...pleasant weather expected with high pressure
building across the region. The upper low will pivot across southern
Quebec Thursday-Friday, so a few showers will be possible,
particularly in the northern mountains. However, dry weather takes
hold through the end of the week. Conditions will be much more
comfortable as dewpoints will drop back into the 40s and 50s. Highs
will be seasonable, mainly in the 70s, though Friday could be a bit
cooler in spots as the upper low spins just north of the
international border. Overnight temperatures will be in the upper
40s to mid 50s.
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Through 06Z Tuesday...Changeable conditions anticipated this
morning with a window of fog/br and associated ifr possible at
slk/mpv. In addition, line of showers/embedded storms will
impact our western taf sites btwn 09z-12z this morning with a
period of mvfr vis/cigs. IFR in fog/br most likely at slk
through 09z, however expecting conditions to improve as
clouds/precip and mixing develops with approaching line of
showers. Meanwhile, at mpv thinking fog/br develops btwn 06-07z
associated with window of clearing skies and light winds, before
lifting around sunrise. Elsewhere, mainly vfr conditions prevail
with approaching showers toward sunrise. Expect south/southwest
winds to increase behind showers at 10 to 15 knots with
localized gusts up to 20 knots at slk/mss and btv.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Slight chance SHRA.
Wednesday: VFR. Chance SHRA, Chance TSRA.
Wednesday Night: Mainly VFR, with local MVFR possible. Likely
SHRA, Slight chance TSRA.
Thursday: Mainly VFR, with local MVFR possible. Chance SHRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: Mainly VFR, with local MVFR possible. Slight chance SHRA.