Scientific Forecaster Discussion
fxus61 kbtv 211751
Area forecast discussion
National Weather Service Burlington Vermont
151 PM EDT Mon Oct 21 2019
cloud cover and southeasterly winds will increase tonight
through Tuesday afternoon before a cold front pushes through,
bringing a widespread soaking rain Tuesday afternoon through
Wednesday morning. While the widespread rainfall will end early
Wednesday, cloudy and occasionally showery conditions will
continue through the end of the week as a series of upper waves
Near term /through Tuesday/...
as of 1001 am EDT Monday...primary forecast challenge this
morning is some pesky dense valley fog that is lingering into
the mid to late morning hours. Can see the fog clearly on
satellite imagery throughout the lower Champlain Valley,
Connecticut valley, Saint Lawrence valley, and in local smaller
valleys. As mixing begins to increase this morning a few hours
past sunrise, seeing signs of the fog beginning to erode. Should
see improvement in visibilities between 10 am and noon,
after which skies will be mostly clear. Otherwise forecast on
track, previous discussion follows.
Best day of the week will be today as surface high pressure and
a weak ridge aloft crest over the region. After dense morning
valley fog Burns off, sunny skies are expected for the afternoon
with light winds and highs a good deal above normal in the
upper 50s to lower 60s.
While dry conditions will persist tonight into early Tuesday, skies
will become increasingly cloudy as an occluded system currently over
the central Continental U.S. Tracks into the Great Lakes. Light boundary winds
early this evening will give way to an increasingly low-level
south/southeasterly jet which will keep locations from the Champlain
Valley westward relatively mild in the mid/upper 40s, while east of
the Green Mountains a lighter wind regime will allow temps to fall
into the upper 30s and lower 40s. As the occluded front advances
towards the north country on Tuesday, downsloping winds along the
western slopes of the Green Mountains and northern Adirondacks will
develop with gusts of 25-40 mph expected from mid-day Onward until
the onset of precipitation which will be across the St. Lawrence
Valley just before the evening rush, and not into Vermont until
after sunset. Highs Tuesday under thickening cloud cover will range
through the low 60s.
Short term /Tuesday night through Wednesday/...
as of 340 am EDT Monday...rain will quickly spread from west to east
Tuesday evening/overnight as an occluded front pushes across the
north country. A strong south jet will cause moisture to surge
northward ahead of the front, with pwats of 1+ inch possible. Rain
may be moderate to briefly heavy at times overnight, but the front
should be progressive enough to preclude any significant flooding
concerns. The front will move east of our region Wednesday morning,
bringing the steady rain to an end. However, scattered showers will
continue through much of the day, particularly over the higher
terrain of the northern greens and Adirondacks as winds turn to the
west southwest Post-front, allowing lake enhanced moisture to stream
into the higher elevations. Lows will mainly be in the 40s Tuesday
night, followed by seasonal highs in the 50s on Wednesday.
Long term /Wednesday night through Sunday/...
as of 340 am EDT Monday...we'll see a brief break in the
precipitation Wednesday night with high pressure builds to our
south. We'll be under southwest flow with several shortwaves to move
overhead through the period. Models are having a hard time agreeing
on the placement, timing, and strength of these shortwaves; hence
while there will be several chances for precipitation through latter
half of the week into the weekend, the details are still in question
at this time. Have stayed with mainly chance pops given this
uncertainty. Temperatures do look to cool down a bit toward the end
of the week, especially over the weekend. Wouldn't be surprised if
the higher elevations see some light snow mix in with any rain
Aviation /18z Monday through Saturday/...
through 18z Tuesday...mostly VFR conditions expected for all taf
sites through 18z Thursday. Expecting some localized fog/low
stratus over some of the valleys of southeastern Vermont between
08z and 13z, but for the most part this should not affect any of
the taf sites. Kmpv may see some temporarily reduced flight
conditions during this time, but confidence not high enough to
include in the taf at this point. A cold front will move through
the forecast area Tuesday, mainly after 18z, but expecting some
gusty southerly/southeasterly winds ahead of the front Tuesday
morning. A southwesterly low-level jet will move over northern
New York after 08z, so have included some low level wind shear at kmss and kslk given
surface flow will remain relatively light. In addition to low-
level wind shear, some turbulence can be expected after 08z,
especially over the northern Adirondacks.
Tuesday night: mainly VFR, with areas MVFR possible. Definite ra,
chance rain showers.
Wednesday: mainly VFR, with local IFR possible. Chance rain showers.
Wednesday night: VFR. No sig weather.
Thursday: VFR. Slight chance rain showers.
Thursday night: mainly VFR, with areas MVFR possible. Chance
Friday: mainly MVFR, with areas VFR possible. Chance rain showers.
Friday night: mainly MVFR, with areas VFR possible. Chance rain showers.
Saturday: mainly MVFR, with areas VFR possible. Slight chance