826
FXUS61 KBUF 190916
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
516 AM EDT Sun May 19 2024

.SYNOPSIS...
High pressure extending from the Labrador Sea and the Canadian
maritimes back across our region will generally keep fair dry
weather in place through at least the beginning of the new work
week. More notable will be the summer like heat that we can look
forward to, as the mercury in most areas will climb WELL into the
80s for the Monday through Wednesday timeframe.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
While fair dry weather will be in place throughout the region
overnight, as was expected lingering low level moisture is
encouraging fog development, especially across areas west of the
Genesee Valley. Expansion of the fog can be seen quite nicely on
Nighttime Microphysics satellite. It will stay on the mild side of
average with lows mainly in the mid and upper 50s.

After early morning fog and stratus dissipate, mainly dry weather is
expected Sunday as a mid and upper level ridge starts to build
overhead. There will be an outside chance for some diurnally driven
scattered showers across the Genesee Valley/Finger Lakes with a weak
lingering surface convergent boundary in place. High temperatures
should peak in the mid to upper 70s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
Summer-like warmth will be the main story as daytime temperatures
climb solidly into the 80s both Monday through Wednesday. We might
even see a few locales touch 90F, especially in the Genesee Valley
on Tuesday and Wednesday. A shower or even an isolated thunderstorm
will be possible well inland from the lakes on Monday.

On Tuesday...a shortwave is advertised to crest over the top of the
500mb ridge. This feature will bring some showers to the St.
Lawrence Valley in the morning, and then additional showers and
possibly a thunderstorm in the afternoon inland from the lakes.

Southwest flow strengthens across the eastern Great Lakes Wednesday
as low pressure tracks from Lake Superior to near Hudson Bay. The
warmth will peak on Wednesday as H850T`s reach its maximum aloft of
+15C to +17C. This will easily support highs in the mid to upper 80s
near 90F. No record highs anticipated at KBUF or KROC but we could
near it at KART (86F:1985). Additionally...this will likely be the
best chance for showers and thunderstorms as a pre-frontal trough
arrives across the region near peak heating. Right now...BUFKIT
sounding profiles show CAPE values ramping up to 1300-1600 J/kg in
the afternoon, and 35 knots of 0-6 km shear. Given the favorable
timing...we could see some stronger storms develop inland from the
cooler stable lake environment. Will need to keep an eye on
temperatures and the potential for strong storms as we move closer.

Showers and thunderstorm potential will continue as we head into
Wednesday night as the cold front nears and crosses the region
overnight. Mild muggy night expected ahead of the cold front with
lows expected in the 60s.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
The cold front should be in the process of exiting the region or
just to our east by Thursday morning. There may still be some
showers that linger behind the front on Thursday but should be
fairly limited coverage wise. Otherwise...it will be cooler Thursday
with highs in the low-mid 70s.

A secondary cold front is advertised to cross the region late
Thursday night or even early Friday which will deliver a second shot
of cooler air to the eastern Great Lakes. That said...the main
challenge will be how much cooler with H850 temperatures potentially
down to +4C to +7C. Guidance still shows anywhere from low-mid 60s
to low-mid 70s. Will lean on NBM guidance at this point which is
right in the middle with upper 60s to around 70F for daytime highs
on Friday. The cooler airmass rapidly modifies over the weekend with
a warming trend taking place across the region.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
VFR conditions expected east of Lake Ontario (KART) right through
Sunday with solid mid level decks remaining in place through the
remainder of the overnight. Meanwhile conditions deteriorate from
east to west south of Lake Ontario, with the worst conditions
(VLIFR/LIFR) across the Niagara Frontier (KBUF/KIAG) and far
southwestern NYS (KJHW) where VSBYs have fallen to a quarter mile
over the past 1 to 2 hours. Nighttime Microphysics satellite shows
the denser fog expanding inland from the western Lake Ontario and
eastern Lake Erie shorelines. Lower Genesee Valley will likely be in
between VFR to the east and VLIFR to the west, so the battle at KROC
will be between the formation of fog versus stratus.

Heading into Sunday, low stratus and fog over western NY will slowly
improve to VFR through the mid to late morning hours. Widespread VFR
conditions then expected for Sunday afternoon and evening, although
there may be a stray shower or rumble of thunder toward the upper
Genesee Valley during the afternoon.

Outlook...
Monday and Tuesday...mainly VFR.
Wednesday...VFR/MVFR. Showers and thunderstorms likely.
Thursday...Mainly VFR. A chance of showers and thunderstorms.

&&

.MARINE...
A highly saturated air mass will continue over the lower Great Lakes
tonight allowing for fog and stratus to expand over the Lakes with
poor visibility conditions possibly becoming widespread late tonight
into the first half of Sunday on Lake Erie and the western end of
Lake Ontario with light flow.

Otherwise, light winds with minimal wave action expected on the
lakes through Monday.

South winds develop and begin to pick up by Tuesday as a cold front
near the eastern Great Lakes but conditions will likely remain below
small craft levels. The next chance at small craft conditions may
materialize by midweek as low pressure sends a cold front through
the Lakes.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Dense Fog Advisory until 10 AM EDT this morning for NYZ001-002-
     010-011-019-085.
MARINE...Dense Fog Advisory until noon EDT today for LEZ040-041.
         Dense Fog Advisory until noon EDT today for LOZ042-
         062.

&&

$$

SYNOPSIS...RSH
NEAR TERM...JM/RSH/TMA
SHORT TERM...AR
LONG TERM...AR
AVIATION...JM
MARINE...JM/TMA