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461
FXUS61 KBUF 191039
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
639 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 /THROUGH TONIGHT/...
Continued expansion of the fog (across far western NY) and stratus
(interior Southern Tier and Genesee Valley/western Finger Lakes)
continues to be seen quite nicely on Nighttime Microphysics
satellite early this morning. With most observations hovering at or
near one quarter mile and widespread nature of dense fog seen on
satellite, have issued a Dense Fog Advisory valid through 10 AM for
the Niagara Frontier southward along the Lake Erie shore into
Chautauqua County.

Otherwise, following the dissipation of morning fog and stratus,
amplifying mid and upper level ridge overhead will provide mainly
dry weather today. There will be an outside chance for some
diurnally driven scattered showers and possibly an isolated rumble
of thunder across the Genesee Valley/Finger Lakes region with a
lingering weak surface convergent boundary in place there. High
temperatures should climb into the mid to upper 70s.

High pressure will provide dry weather tonight. Although low level
moisture looks to be a bit less tonight, there may still be enough
to produce some areas of fog again overnight, mainly south of Lake
Ontario. However, it should not be as widespread or dense as last
night. Another mild night with lows in the mid to upper 50s.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
Summer-like warmth will be the main story as daytime temperatures
climb solidly into the 80s 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.
-- End Changed Discussion --

&&

.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 /12Z SUNDAY THROUGH THURSDAY/...
VFR conditions expected east of Lake Ontario (KART) right through
this evening. 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 down to a quarter mile continue. 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 IFR to VLIFR to the
west. Currently low CIGS/VSBY (KROC) across the lower Genesee Valley
early this morning.

Heading into today, 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 this 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 airmass and weak flow will continue over the
lower Great Lakes today allowing for fog and low stratus to continue
over the Lakes with poor visibility conditions across eastern Lake
Erie and western Lake Ontario, for which a Dense Fog Advisory has
been issued through 12 PM today.

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
SHORT TERM...AR
LONG TERM...AR
AVIATION...JM
MARINE...JM/TMA