477
FXUS61 KBUF 070238
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1038 PM EDT Thu Jun 6 2024

.SYNOPSIS...
Behind the passage of a secondary cold front, a cooler and less
humid airmass will stay in place through early next week.
Unfortunately, the cooler conditions will be accompanied by
unsettled conditions with fairly frequent showers. Warmer weather
will return later next week.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
The second of two cold fronts will push through the area tonight.
This front will lead the charge of a cooler and less humid
airmass. While the vast majority of the region will experience
fair dry weather tonight...deeper moisture circulating around a
deep longwave trough over eastern Canada will nose across the
far western counties. This will support the chance for some
nuisance showers and perhaps an isolated thunderstorm over the
far western areas...and with H85 temps forecast to drop to arnd
6c...there could actually be some lake enhancement east of both
lakes. Otherwise...it will be a night to open those windows to
allow the fresh new airmass indoors. Mins will range from the
mid and upper 50s across the lake plains to the lower 50s across
the bulk of the Srn Tier and across the Tug Hill.

A very unsettled pattern will continue Friday through the weekend as
a mid level closed low moves very slowly from near Georgian Bay
Friday morning eastward across southern Quebec over the weekend. A
multitude of shortwaves will round the base of the closed low and
bring periods of enhanced ascent and deeper moisture to our region,
producing frequent rain chances. These smaller scale shortwaves
become more difficult to place in time and space beyond a few days,
with the finer details of the forecast becoming more uncertain
beyond Saturday.

Friday, the base of the mid level low will move across the eastern
Great Lakes, bringing with it a period of deep moisture and ascent.
Cool temperatures aloft will support steepening lapse rates with
modest diurnal heating. The coverage of showers should still be
rather sparse early in the morning, but expect a quick expansion of
shower coverage and intensity by late morning into the afternoon as
the deeper moisture and forcing arrive and interact with steepening
lapse rates. Instability will be weak, but still may support some
isolated thunder in the afternoon and evening. Stable lake shadows
will keep shower coverage lower east and northeast of Lake Erie and
Lake Ontario, but the synoptic forcing may be strong enough to
overcome the lake shadows to some extent.

Friday night, showers will continue as the trough moves slowly east.
Temperatures aloft become cool enough to support lake enhanced
showers east of the lakes, especially east of Lake Ontario overnight
as 850MB temps fall to around +5C or so. This is a rarity in June,
but the cool temperatures aloft combined with well above normal lake
temperatures will bring our first lake effect rain showers of the
2024-2025 season.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH THROUGH SUNDAY NIGHT/...
Heading into the weekend, a broad upper level closed low centered
just north of the Great Lakes will continue to gradually slide
east. Also through this time, multiple hard to time mid-level
shortwaves will pass through cyclonic westerly flow across the
Great Lakes. The 12Z model guidance continues to support the
more vigorous wave to push across the eastern Great Lakes
Saturday night. With this comes a better chance for organized
rainfall and weak diurnally supported isolated thunder. Chances
for showers and storms will then continue through Sunday and
Sunday night as the upper level pattern shifts east.

With regards with temperatures, upper level troughing aloft will
support below normal temperatures. Highs Saturday and Sunday will
range in the 60s.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
The same general longwave pattern will remain in place across North
America through early next week, with an expansive ridge in the west
and a trough in the east. The trough and associated forcing, deeper
moisture, and cool air aloft will continue to support showers and
cool temperatures through at least Monday. By Tuesday, forecast
model guidance continues to show the trough axis making some
eastward progress to along or just off the east coast. There may
still be a few spotty showers, especially in the afternoon across
higher terrain inland from the lakes, but the coverage of showers
should be much lower than previous days.

Tuesday night and Wednesday height rises will spread across the Ohio
Valley and eastern Great Lakes ahead of another trough digging into
the upper Great Lakes. This will bring a brief interlude of dry
weather, but shower chances may start to increase again as early as
Wednesday afternoon and continue through Thursday with the approach
of the upstream trough. Temperatures will warm through midweek as
the pool of cool air aloft exits.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Mainly VFR weather will then be in place for tonight...despite the
passage of a second front.

Deepening moisture rotating around the base of a large trough will
encourage cigs to drop to MVFR levels on Friday. The lowering cigs
will be accompanied by some showers and possibly a thunderstorm or
two.

Outlook...

Saturday through Monday...VFR/MVFR with mainly daytime showers
likely with possible thunderstorms.
Tuesday...VFR conditions.

&&

.MARINE...
SW to WSW winds will freshen on both Lake Erie and Lake Ontario
through Friday in the wake of the cold frontal passage with choppy
waters developing. Conditions may possibly near Small Craft Advisory
criteria for a couple of brief periods, especially across Lake Erie.

&&

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

&&

$$

SYNOPSIS...RSH/TMA
NEAR TERM...Hitchcock/RSH/TMA
SHORT TERM...EAJ
LONG TERM...EAJ/Hitchcock
AVIATION...RSH/TMA
MARINE...Apffel/HSK/JM/TMA