515 
FXUS61 KBUF 011058
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
658 AM EDT Tue Aug 1 2023

.SYNOPSIS...
While a very cool airmass could support spotty lake effect showers 
southeast of the lakes this morning...then a few instability showers 
well inland this afternoon...a large area of high pressure will keep 
the VAST MAJORITY of the region rain free through Wednesday. We can 
then anticipate summer warmth to return ahead of a cold front on 
Thursday...as a stretch of showery weather can be expected late 
Thursday into Friday. A look down the road at the weekend reveals 
that there is high confidence for fair dry weather.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
The majority of the region will experience fair dry weather today... 
as a large area of high pressure will slowly drift across the Lower 
Great Lakes. There will be a few showers around though...largely due 
to the cool airmass that is in place. To start...a weak lake response
to the single digit H85 temps could support a few nuisance showers
southeast of both lakes through mid morning. As we work our way into
the midday hours though...strong late summer diurnal mixing will
eliminate this scenario.

The cool airmass with its steep low level lapse rates will then set 
the stage for some 'self destruct' sunshine that will lead to a 
wealth of afternoon Cu and possibly some widely separated showers 
well INLAND from the lakes. For most areas though...the day will 
feature rainfree weather.

It will be quite cool today with afternoon temps only reaching into 
the low to mid 70s. Upon the Tug Hill...the mercury may do not 
better than the mid 60s. As a reminder...normal highs for the start 
of August (just past thermal solstice) are close to 80.

The expansive area of high pressure will slowly creep to our east 
tonight. Given the very cool airmass in place...this scenario should 
promote some of the coolest weather of the next week or so with mins 
tonight ranging from the mid 40s in the interior of the Srn Tier to 
the mid 50s across the lake plains. This will be nearly 10 deg f 
below normal values to start the month of August. 

The heart of the sfc high will make its way across New England on 
Wednesday. The weak return flow around the backside of the sfc high 
will establish enough warm advection to allow H85 temps to climb 
back to arnd 12c...which in turn will enable our afternoon temps to 
climb into the mid to upper 70s.This should make Wednesday one of 
the nicest days in the forecast package with abundant sunshine and 
comfortable conditions.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
High pressure along the Northeast coast will exit out to sea early 
Wednesday night. Meanwhile...initial shortwave energy dropping 
through the longwave trough will be in the process of racing across 
E. Ontario/Quebec. This feature and a warm front working through the 
area will bring increasing chances for showers...mainly concentrated 
across the North Country and St. Lawrence Valley. Have added chance 
POPs for this region to cover this threat overnight. Elsewhere...dry 
weather will likely persist for all of western New York. 

Otherwise...southerly flow ahead of a slow approaching cold front 
will usher in a somewhat muggy and milder airmass overnight as we 
head into Thursday. This will help to add 5F to 10F onto overnight 
lows temps which will be found mainly in the upper 50s to 60s across 
western New York...a bit cooler across interior locations of the 
North Country.  

Shortwave energy will continue to dig south and east Thursday which 
will slowly push a cold front towards the Lower Lakes. A prefrontal 
trough ahead of the front is advertised to work through the region 
in the mid/late afternoon...the best shot to see showers or 
thunderstorms still appears to be focused across eastern and 
southeastern portions of the area. This is where the higher PWATs 
reside of +1.25 inches. That said...the SVR potential still looks 
rather limited or paltry at this point given shear values of < 30 
knots and then only 500-1000 j/kg SBCAPE.   

Thursday evening/night...the shortwave and weak sfc reflection over 
Quebec will slowly push the cold front into and through the Lower 
Lakes. There will be some chances for showers or a storm as the 
front slowly sags into and through the area. on Friday...the mid-
level circulation to our north will send a secondary frontal 
boundary southward towards and then through the region. This will 
again touch of a few more showers or even a thunderstorm in the 
afternoon into the evening. It will also signal the arrival of 
cooler aloft with H850 temperatures dropping to +7C to +10C. After 
that...any showers or storms will fade as we move through Friday 
night. This will occur with the loss of daytime heating and as drier 
air circulates into the Lower Lakes overnight.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
High pressure builds in at all levels on Saturday which will provide 
fine August weather across the entire area. Highs will top out in 
the 70s areawide.  

Dry and quiet weather continues Saturday night as highs pressure 
slides overhead. Lows expected in the 50s to low 60s. 

Surface high pressure will slowly slide east of the area of Sunday 
but will maintain dry weather. Temperatures will be a bit warmer as 
southerly flow develops on the western flank of the departing high. 
Looks for temps in the upper 70s to low 80s. 

After Sunday...still a lot of uncertainty in regards to the next 
upstream shortwave which is advertised to potentially track across 
the upper Midwest and then into the Great Lakes region. Have capped 
POPs for now in the slight chance/chance range below NBM guidance 
for Sunday night/Monday...atleast until there is better agreement 
with the shortwave overall evolution.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
After the morning fog and stratus burns off across the Southern 
Tier...all of western and north central New York will be able to 
enjoy fine VFR weather with light winds.

VFR conditions will persist tonight...although patchy fog will once
again develop across parts of the Southern Tier after 08z.

Outlook... 

Wednesday...VFR. 
Thursday and Friday...Mainly VFR with a chance of showers and 
thunderstorms.
Saturday...VFR.

&&

.MARINE...
While high pressure over the region today will only allow for light 
winds and negligible wave action...there will still be the risk for 
isolated waterspouts through the morning hours. A very cool airmass 
has allowed for land breeze boundaries to drift out across both 
lakes early this morning...and these will serve to focus enough low 
level convergence to support widely separated showers or isolated 
waterspouts. The KBUF radar confirmed the presence of a such a 
boundary at 11z and surrounding observations added evidence of this 
low level focusing feature.

Light winds and minimal waves will then persist tonight through 
Wednesday...as the area of high pressure will slowly exit to our 
east.

&&

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

&&

$$

SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...AR
LONG TERM...AR
AVIATION...RSH
MARINE...RSH