Forecast Discussion

Forecast Discussion for BUF NWS Office
FXUS61 KBUF 211831

Area Forecast Discussion
National Weather Service Buffalo NY
231 PM EDT Wed Oct 21 2020

There will be a round of showers and possibly a thunderstorm this
afternoon as a cold from moves through the area. Most of tonight
will be dry, then a warm front will lift back northward across the
area late tonight and Thursday. This front will bring a few showers
on Thursday, followed by warmer weather by Friday. A cold front will
cross the area late Friday night, bringing some showers and then
much cooler air for the weekend.


At 2 p.m. a cold front extends across our region roughly from
JHW-ROC-ART. This front is producing a fairly solid line of
showers which will continue to move eastward with the frontal
boundary. There are also a few spotty showers, and possibly a
thunderstorm out ahead of this boundary where warmer
temperatures in the lower to mid 70s support modest instability.
It will also be breezy this afternoon, with S-SW winds gusting
to 35 mph near the frontal boundary.

Tonight will be mainly dry as a bubble of high pressure briefly
builds over the eastern Great Lakes. Abundant low level moisture,
wet ground, and light surface winds may allow for at least
patchy fog to develop from late evening through the overnight
across much of the region. If skies clear there is the potential
for more widespread fog.

00Z model guidance suggests a greater chance for showers with a
warm frontal segment and associated mid-level warm air
advection late tonight and Thursday. Some showers may develop
late across the Southern Tier as a warm frontal segment begins
to come together ahead of the next system moving through the mid
section of the nation. Showers should become a bit more
widespread Thursday morning as this boundary lifts northward
across the area.

Because of the front, there will be a wide range of temperatures
across the area on Thursday. Forecast favors high resolution
model guidance, with forecast highs ranging from the lower 70s
across the Western Southern Tier to the upper 50s from Buffalo
to Rochester northward.


A developing low pressure system over the Mid-West will be the
driver of the weather conditions throughout the entirety of this
period. To start off, the developing surface low will track
east-northeast from Iowa to the western Great Lakes Thursday
night. As such, the low`s associated warm front will push
northeast, though the front will remain north of the region
which will promote warm and dry conditions for a vast majority
of the region.

Warm dry conditions will prevail Friday as the region will remain
underneath the warm sector of the low pressure system. Lack of cloud
cover combined with the warm air aloft will promote high
temperatures in the mid to upper 70s.

The aforementioned surface low will continue to traverse northeast
across eastern Canada Friday and Saturday. As such, it will drag its
associated cold front across the lower Great Lakes and New
England. More specifically for the local scale, the cold front
will approach far Western New York Friday evening and cross the
remainder of the state Friday night into Saturday morning. There
is a slight chance for an isolated thunderstorm across far
Western New York as the front nears, but confidence is low. With
the eastward progression of the front, shower intensity will
gradually diminish heading into Saturday morning as high
pressure builds across the Great Lakes and eventually push into
the region.


An area of surface high pressure will pass across the Great Lakes
and southeastern Canada Saturday and Sunday, resulting a period of
dry conditions Saturday night into Sunday.

The remainder of this period continues to be unsettled. A deepening
upper level trough over Western CONUS will propagate eastward
resulting in the next low pressure system to advance northeast
across the Mississippi Valley and Mid-Western portions of the lower
48. Model guidance differs on the exact position and timing, but an
overall generalization would be a warm frontal passage early on in
the week followed by the passage of a cold front sometime after,
while high pressure will follow in the wake of the low pressure
system and its associated frontal boundaries passages. Thus,
better chances and likelihood for showers occur early on in the
week and begin to back off by Wednesday, will have to keep an
eye on this system as time advances forward.


A cold front extending from KJHW-KROC-KART at 18Z will continue
to push eastward this afternoon. This front will produce briefly
lower cigs/vsby along and just behind it. This will be most
noticeable at KJHW, where several hours of IFR are expected.

Overnight a bubble of high pressure moves into the eastern Great
Lakes. Light winds and leftover low level moisture may allow
for fog and/or low stratus to develop overnight with areas of
IFR. Forecast confidence in fog is low, since it will depend on
subtle differences in cloud cover. The best chance for stratus
and fog is the Western Southern Tier where there will be
moisture trapped beneath an inversion near the front.

Stratus and fog will gradually dissipate during the day
Thursday, with conditions improving from IFR/MVFR to mainly VFR
by the afternoon.


Thursday night...Mainly VFR.
Friday night and Saturday...MVFR with showers likely, improving
to VFR Saturday afternoon.
Sunday night and Monday...VFR/MVFR. Showers likely.


A cold front is across Lake Ontario this afternoon, with a
moderate SSW flow ahead of this boundary. This supports small
craft headlines for many of our nearshore waters as outlined
below. Winds will diminish behind the front through this

Northeast winds will develop again on Thursday, producing
choppy conditions on both lakes, but Small Craft Advisory
conditions are not expected. Winds will become southerly later
Thursday night and Friday ahead of the next cold front.


MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LEZ020.
         Small Craft Advisory until 8 PM EDT this evening for
         Small Craft Advisory until 5 PM EDT this afternoon
         for LOZ042.
         Small Craft Advisory until 11 PM EDT this evening for
         Small Craft Advisory until 5 PM EDT this afternoon
         for SLZ022.



NEAR TERM...Apffel/Hitchcock

NWS BUF Office Area Forecast Discussion