FXUS61 KBTV 172351
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
751 PM EDT Wed Jul 17 2019
An active period of weather is expected across the North
Country through Saturday. Cold front pushes south tonight and
drier weather is expected for Thursday and Thursday night. Hot
and humid conditions are expected on Friday and Saturday. There
could be some late afternoon and evening thunderstorms on
Friday. The best chance for thunderstorms, some of which could
be strong or severe, looks to be Saturday afternoon and night.
.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 614 PM EDT Wednesday...Scattered showers and a few
embedded thunderstorms across nrn NY and VT will continue
moving sewd at 15-20 mph this evening. Main impact from this
activity has been locally heavy downpours, including reports of
1+" in 30 minutes time in the Westford, VT area around 4pm.
Marginal lapse rates have kept lightning activity low, and
generally not expecting any increase in lightning during the
next several hours. Eventually, the strong cold front
progressing southward across the Ottawa Valley and near
Montreal, Quebec will bring in drier air after midnight tonight,
with dewpoints falling from the lower 70s into the low-mid 60s
by daybreak (lowest dewpoints near the intl border). It appears
that initial clearing later this evening will result in fog
formation given very muggy conditions and saturated soils in
many locations. However, as north winds increase and dewpoints
drop late tonight, may see some of the fog dissipate during the
pre-dawn hours. Continued with overall idea of patchy dense fog
overnight. Minimum overnight temperatures will be around the
upper 50s to mid 60s.
Thursday will generally be a quieter weather day with
temperatures close to seasonal normals. Could have some showers
develop in Northern New York Thu afternoon on southwesterly flow
with a warm front lifting across the area, have slight chance
for showers mentioned at this time. Any showers that develop Thu
afternoon will die down following sunset. A bit of shortwave
energy passes through southwesterly upper level flow Thursday
night and will have a chance of showers early Friday morning
entering our western zones.
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 254 PM EDT Wednesday...Friday is looking to be an incredibly
hot and humid day with temperatures especially in the valley
locations pushing 90 with dew points in the low to mid 70s across
the board. Heat Index values will be pushing mid to upper 90s,
building throughout the day with such high dewpoints. Heat
advisory will be likely for the valleys. During the morning
hours a warm front pushing north along with elevated instability
may result in showers with a rumble of thunder across northern
NY into the CPV. Significant diurnal heating throughout the day
will lead to an increased risk of spot thunderstorms working
their way in during the late afternoon into early evening hours.
Lack of forcing and limited deep layer moisture will result in
isolated to widely scattered coverage. Northern NY into northern
VT would have the best chance for these storms to develop,
which should quickly dissipating with their movement eastward.
Southerly winds will be increasing throughout the day as mixing
improves and gradient sharpens with approaching boundary, with
highest speeds over the trrn. Friday night, warm and muggy
temperatures will remain in the low 70s in valley locations with
upper 60s elsewhere, while still keeping the dewpoint in the
upper 60s to low 70s. The overnight looks to be relatively calm
weather wise before what`s expected to be the warmest day of the
season on Saturday with similar atmospheric conditions to
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 254 PM EDT Wednesday...Active period of weather
anticipated for Saturday into Sunday with very warm/humid
conditions and the chances for strong to severe thunderstorms.
The highest combination of heat/humidity values will be Saturday
aftn where heat index values will be in the lower 100s in the
warmer valleys. Many parameters coming together for scattered
strong to severe storms Saturday aftn/evening.
Saturday is looking to be yet again another hot and humid day
with air temperatures pushing into the upper 80s to mid 90s.
Heat index values will be climbing into the upper 90s with the
low 100s not out of the question, with the oppressive dew points
in the upper 60s to mid 70s. These temperatures are supported
by 925mb level temperatures ranging from 26-28 celsius, with
dry/super adiabatic conditions only impacted by increased cloud
cover or precipitation. Associated daytime heating and upper
level wind shear of 35-45kts will lead to the development of
strong to severe thunderstorms working their way through our
area. Still some uncertainty on timing of sfc boundary and upper
level support for providing synoptic scale lift. However, with
CAPE values in the 2500 to 3500 j/kg and deep layer shear of 35
to 45 knots, will produce an environment favorable for organized
convection with scattered strong to severe thunderstorms
possible. South winds 10-20kts surface and mid level winds of
40-50kts will enhance deep layer shear to support organized
convection Saturday afternoon. Looking at Saturday night,
temperatures will follow the same pattern as the night before
with temperatures looking like they will break the 70 degree
mark, with lows in the mid to upper 60s. The dewpoint during the
overnight hours still remains at the mid to upper 60s, with the
NEK seeing the most comfortable overnight conditions. Lingering
instability could produce the occasional thunderstorm moving
through the area as that should not be ruled out of the
Sunday through Tuesday...Large scale pattern change will slowly
evolve by early next week. Still some uncertainty how quickly
the sfc boundary and associated dynamics will drop south of our
cwa. Latest 12z ECMWF continues to show lingering
instability/moisture across our central/southern CWA on Sunday
with pws near 2.0. Have continued to mention chc pops with some
thunderstorms possible, given instability. Temps will range from
the mid 80s to lower 90s across our cwa, with lowering dewpoint
values as north winds develop. Sfc high pres and deeper drying
will result in comfortable temps/humidity levels for early next
week, with decreasing chcs for precip. Highs mainly in the mid
70s to lower 80s.
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...Scattered showers are diminishing this
evening ahead of a frontal boundary to the northwest. Satellite
imagery shows clear skies behind the front...so as the boundary
pushes through overnight the North Country will see clearing
skies. Expecting fairly widespread BR/FG to develop between 03Z
and 11Z, which will reduce visibilities to MVFR/IFR ranges with
the potential for some localized temporary LIFR visibilities.
Expecting the BR/FG to affect KSLK and KMSS fairly early
tonight, then will see improvement at these sites as drier air
moves in overnight. However, KMPV, KBTV, and KRUT will see
longer period of reduced visibilities overnight lasting until
09-12Z. Light and variable winds overnight will become
southeasterly 5-10 kts after 15Z. The exception will be KMSS,
which will maintain northeasterly flow 4-10 kts through the TAF
Thursday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Friday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight
Friday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Saturday: VFR. Chance SHRA, Chance TSRA.
Saturday Night: VFR. Chance SHRA, Chance TSRA.
Sunday: Mainly VFR, with local MVFR possible. Chance SHRA, Chance
Sunday Night: VFR. Chance SHRA.
Monday: Mainly VFR, with local MVFR possible. Chance SHRA.