Scientific Forecaster Discussion
fxus61 kbtv 230538
Area forecast discussion
National Weather Service Burlington Vermont
138 am EDT Wed Oct 23 2019
gusty southerly winds will begin to diminish this evening as
widespread precipitation spreads over the area. A front will
move through during the overnight hours, bringing between a half
and one inch of rain through Wednesday morning. Steady rain
will taper off into some spotty showers during the day on
Wednesday. The remainder of the week will feature daily chances
for showers, partly to mostly cloudy skies, and breezy
Near term /until 2 PM this afternoon/...
as of 1005 PM EDT Tuesday...forecast playing out nicely with
rain at most locations...will be over the Northeast Kingdom of
Vermont before midnight...and eventually have the back edge move
from west to east overnight across the area. All of this handled
well in the forecast and really only looking at minor
temperature and dew point tweaks to match current conditions.
Rest of forecast remains unchanged.
continued gusty winds and developing widespread rainfall are
the primary forecast concern for the overnight hours as a cold
front to our west is poised to push through tonight. Ahead of
the front, southerly flow has increased through the day today
thanks to a 45+ kt low level jet moving overhead. Some of this momentum is
sporadically mixing to the surface, but given the strong warm
air advection in place the brunt of the strongest flow is
staying aloft. Consequently, winds will continue to be in the 5
to 15 mph range with some gusts up to 25 mph possible through
early evening. The exception will be higher elevations
(generally above 1500 ft) and Lake Champlain and the immediate
vicinity, which will see more sustained 15 mph to 30 mph winds.
Once the sun sets and widespread rainfall develops this evening,
winds will begin to decrease as the boundary layer stabilizes.
In terms of precipitation, there may be some spotty warm air
advection-driven showers observed through early evening.
However, the more widespread rainfall still has yet to move
through and remains to our west. General timing of the start of
the more steady rainfall is between 3 PM and 8 PM over northern
NY, and generally between 8 PM and midnight in Vermont. The
heaviest rain will fall in the overnight hours before tapering
off into showers Wednesday morning. Total quantitative precipitation forecast between this
afternoon and Wednesday morning is on track for between two
thirds of an inch up to an inch.
After the front clears the area Wednesday morning, the remainder
of the day will trend drier...with the exception of some lake
effect showers lingering over parts of northern New York. These
showers will be light in nature however, and many areas likely
won't measure any precipitation at all. Despite the Post-
frontal southwesterly flow Wednesday, mid-level temps will
steadily fall through the day...with cold air wrapping around
the base of a mature cyclone lifting through central Canada. As
a result, expect some gusty southwesterly winds during the
afternoon, especially channeled up the Saint Lawrence valley.
Temperatures will be near seasonal norms.
Short term /2 PM this afternoon through Friday/...
as of 414 PM EDT Tuesday...an upper level short wave passes to the
northwest of our area on Thursday bringing some unsettled weather
across the north country. During this time, windy conditions are
expected with the presence of a low level jet of 40-50kts at 850mb.
Surface winds will be from the southwest at 10-15kts and 25-35kts
across higher terrain. There remains a chance of precipitation
Thursday afternoon, especially across the western County Warning Area and among
higher elevations in New York and northern Vermont. This is supported by a
narrow swath of relatively higher pwats and weak instability with
cape values near 50 j/kg across northern New York and Vermont. In addition, the
southwest flow will result in shadowing across the Champlain Valley
and little chance of precipitation within this region.
Thursday night is expected to remain cloudy ahead of another upper
level short wave approaching from the west, although it is likely to
remain dry. Weak surface high pressure encroaches from the south
Friday morning, funneling moisture into our County Warning Area. Another chance of
precipitation returns Friday evening with the passage of an upper
level short wave, though the timing on its onset remains uncertain.
Due to the breezy conditions and overcast skies, temperatures will
remain at or above normal Thursday and Friday.
Long term /Friday night through Tuesday/...
as of 414 PM EDT Tuesday...conditions look to be drier Saturday as a
surface high pressure settles across the northeast. Beyond Saturday,
however, the GFS and European model (ecmwf) differ greatly regarding the arrival of
the next low pressure system. Due to lack of agreement in the models
and subsequent uncertainty, a chance of precipitation remains in the
forecast for the remainder of the period. In addition, the
temperatures during this time do not stray much from guidance.
Aviation /06z Wednesday through Sunday/...
through 06z Thursday...mix of VFR and MVFR and areas of low level wind shear will
continue in light to moderate rain through 10-12z where
thereafter rain will shift east of the region and ceilings will
lift to VFR. VFR is then expected through the remainder of the
period with south/southwest winds of 8-12kts and locally gusty
up to 20kts at kmss and kslk this afternoon.
Thursday: VFR. Slight chance rain showers.
Thursday night: VFR. No sig weather.
Friday: VFR. Isolated rain showers.
Friday night: mainly VFR, with local MVFR possible. Chance rain showers.
Saturday: mainly VFR, with local MVFR possible. Slight chance
Saturday night: VFR. No sig weather.
Sunday: MVFR. Chance rain showers.