061 
FXUS61 KBUF 131047
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
647 AM EDT Mon Sep 13 2021

.SYNOPSIS...
A cold front dropping across the region will result in a few showers 
over the Southern Tier off an on through the day. Overall expect 
quiet conditions for most of the area. A renewed chance of showers 
and some thunderstorms occurs tonight. Unsettled weather, with a 
risk of strong to severe thunderstorms at times, will continue 
through the middle of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A few showers still over the western Southern Tier close to cold 
front over the Southern Tier to northern Pennsylvania. This front 
will settle over Pennsylvania the rest of the morning. Other than 
the lingering showers, have seen low clouds develop and there has 
already been some fog.       

Frontal boundary does look to remain south of the area rest of 
today, but it will start to work back north as a warm front 
beginning late this afternoon. Convection over western Great Lakes 
just getting going, but is forecast to expand toward lower Great 
Lakes late today into tonight. Latest guidance would suggest maybe 
an arrival to convection as early as very late this afternoon.   

Stronger convection not out of question again tonight WNY to Finger 
Lakes along the slowly moving northward warm front. Ample shear over 
40 kts and strong instability with 0-1km MUCAPES over 1000J/kg along 
and south of warm front from central Great Lakes to lower Great 
Lakes support marginal to slight risk of severe as highlighted by 
SPC. Damaging winds and large hail would be main hazards along and 
north of the warm front.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Sfc low near LK Superior steams NE off into Canada Tuesday morning. 
This feature will finally kick the stalled frontal boundary draped 
over the region north of the Lower Lakes which will then place us 
firmly in the warm sector by the afternoon. Once the warm front 
clears the area, storms will then likely focus along lake breeze 
boundaries ahead of the incoming mid-level trough and approaching 
cold front. SPC has our region in a Marginal Risk with any stronger 
storms capable of producing gusty winds and also very heavy rain as 
PW values will range from 1.3 to 1.5 inches. Additionally, look for 
breezy conditions with southwest winds gusting to 25-30 knots, 
especially NE of the Lakes. Highs will be in the upper 70s to low 
80s.  

Tuesday night, falling heights with the incoming trough and 
approaching cold front will bring increasing chances for showers and 
thunderstorms. The limiting factor will be the the unfavorable 
arrival time of this front (night) across WNY, which will mute its 
potential (waning instability) but not eliminate the threat. That 
said, large scale accent and forcing along this front, in 
combination with the supporting LLJ (+40 knots) and favorable right 
entrance region of the upper jet will likely produce some strong to 
SVR storms. Will mention this in the HWO. 

Wednesday, the cold front slowly progresses from west to east across 
eastern Great Lakes. Showers and storms will slowly work east before 
exiting the entire forecast area by late in the afternoon.
Progressively drier and cooler air will then work in across the 
region as showers end from west to east. Highs will peak in the 70s. 

Wednesday night, sfc ridging to our north will provide dry and quiet 
weather for the Lower Lakes. Lows will generally be found in the 
50s.

&&

.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 /12Z MONDAY THROUGH FRIDAY/...
A few showers through early afternoon over Southern Tier. Patchy 
fog will be possible through daybreak across the Niagara Frontier. 
Otherwise, mix of IFR and MVFR cigs will persist in wake of a 
cold front. Rest of today will feature mainly VFR conditions. 
Tonight, mainly VFR with some MVFR over Southern Tier. 
Thunderstorms are expected western NY to Finger Lakes. Some of 
the storms may be strong. 

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

&&

.MARINE...
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...JLA/TMA
NEAR TERM...JLA
SHORT TERM...AR
LONG TERM...SW
AVIATION...JLA
MARINE...JLA/TMA