146 
FXUS61 KBUF 130022
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
822 PM EDT Sun Sep 12 2021

.SYNOPSIS...
A cold front dropping across the region will support showers and 
scattered thunderstorms. Some of the thunderstorms could produce 
strong winds and heavy rainfall. Unsettled weather will continue 
through the middle of next week with possible showers and 
thunderstorms.

&&

.NEAR TERM /THROUGH MONDAY/...
...Scattered severe thunderstorms possible tonight...

An MCV crossing Lower Michigan this evening is generating strong to 
severe convection. Upstream soundings from 18z were showing a 
pronounced EML...and now 00z soundings from KBUF and KDTX continue 
to show the very favorable environment. CAMs have been consistent 
with timing the convection after 04z for the western counties of New 
York...although some 'garden variety' storms will be possible in the 
hours leading up to that. The main severe weather threat will be 
damaging straight line winds...but there should be intense downpours 
and frequent lightning under the cores as they move through. 

Convection will diminish late tonight as the shortwave (MCV in this 
case) will push east. Some partial clearing could bring some fog 
especially to areas that receive rain.

Frontal boundary does look to sneak south of the area briefly on 
Monday, but will start to work back north as a warm front Monday
afternoon. Shortwave pushing across the area will trigger some 
scattered convection along the frontal boundary late in the day.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A stationary front will be oriented northwest to southeast from 
northern Michigan to northwest Pennsylvania Monday night. Surface 
high pressure will be inching into the North Country resulting in 
dry conditions from the Finger Lakes into the North Country. A weak 
impulse is forecast to ride along the front further west and showers 
with a slight chance of thunderstorms are possible across far 
western NY including the western Southern Tier. Overnight lows will 
range from the low 50s across the North Country to the upper 50s low 
60s across western NY. 

The front will move north as a warm front across western and north 
central NY Tuesday. Dewpoints and mid-level moisture will increase 
while surface temperatures climb to the upper 70s to low 80s. 
Surface based instability will climb with strong winds in the low to 
mid levels. Showers and thunderstorms will likely form by afternoon 
ahead of an approaching cold front. Some storms may become strong to 
severe in the afternoon into the evening. Main threats would be 
strong winds and large hail. Thunderstorms will track east with a 
short break before another round of showers and storms enters the 
region as a cold front approaches from the west. Uncertainty exists 
Tuesday night as the wind field and surface based instability 
decreases ahead of the front. Warm, overnight night with lows in
the 60s.

Model guidance is in agreement that widespread showers or rain with 
thunderstorms will track across the entire forecast area Wednesday 
and Wednesday as the cold front tracks east. This increase in low 
level convergence will initiate thunderstorm development with some 
strong to severe storms. The strongest storms are expected to be 
east of the forecast area however if the front slows down that could 
change. Slightly cooler Wednesday with highs in the mid to upper 
70s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
A sfc ridge will provide for mostly quiet weather for the first half 
of the long term period. Some guidance is suggesting an upper level 
trough/low over eastern PA and southern New England may cause some 
showers for the area. Will need to see how the scenario evolves as 
there is decent model spread still with how much of an impact these 
upper level features will have. For now have high slight chance to 
low chance POPs. A frontal boundary passing south across the area on 
Sunday will bring a few showers and some thunderstorms. The front
will then shift back north as a warm front later on Sunday into
Monday. 

Temps during the long term will be 5 to 10 degree above normal for 
this period.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Complex of thunderstorms with gusty winds and heavy rain looking 
likely to roll across western NY after 3/4z. Brief IFR possible 
during these storms. After the storms later tonight, expect MVFR 
ceilings with IFR possible across the southern Tier. May see some 
fog as well if any clearing occurs. 

Outlook... 
Monday and Tuesday...Mainly VFR with a chance of showers. 
Wednesday...Mainly MVFR with widespread showers. 
Thursday and Friday...Mainly VFR.

&&

.MARINE...
A pseudo stationary cold front straddling Lakes Erie and Ontario
early this evening will gradually push south overnight. In its
wake...gentle to moderate northwesterlies will become
established. While winds and waves will average below small
craft advisory criteria...there will be the risk for strong
thunderstorms between 04 and 08z...particularly over Lake Erie.
mariners should be alert for possible special marine warnings.

High pressure centered over northern Ontario will start to pass
by the north on Monday. This will support light and variable
winds on Lake Erie and light northwesterlies on Lake Ontario. 

As the area of high pressure moves east across Quebec on
Tuesday...a cold front will approach from the Upper Great lakes.
A tightening sfc gradient between the two will lead to
freshening winds on both Lakes Erie and Ontario.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...TMA
NEAR TERM...RSH/TMA
SHORT TERM...HSK
LONG TERM...SW
AVIATION...JLA/TMA
MARINE...JLA/TMA