559
FXUS61 KBUF 051447
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1047 AM EDT Wed Jun 5 2024

.SYNOPSIS...
Today will be the last warm and humid day that most of us experience
in a while...as a slow moving cold front will usher in notably
cooler and less humid conditions that will persist from later
Thursday into the start of next week. The front will generate some
showers and drenching thunderstorms in the process...especially
tonight.

&&

.NEAR TERM /THROUGH TONIGHT/...
Mid level ridge axis will continue to drift to the east of the
region today. A weak shortwave trough/warm front will lift
northeast through the region this morning bringing at least some
risk for a few spotty showers. The area will eventually emerge
into the warm sector behind the departing wave/front with
precipitable water values climbing to near 2 inches, with some
modeled surface dewpoints getting into the upper 60s. Coverage
of showers and thunderstorms will pick up during the afternoon
within the warm sector ahead of an approaching cold front.
Forecast soundings are fairly uniform showing around 1500 J/kg
of SBCAPE and improving shear profiles, suggesting the potential
for some strong/severe storms with the potential for damaging
wind gusts and perhaps large hail. The latest SPC Day 1 outlook
maintains the marginal risk designation for severe weather
across far western New York. Have continued the mention of heavy
rain as the incoming airmass becomes increasingly humid.

Tonight will be quite unsettled throughout the region, as a large
negatively tilted trough over the upper Great Lakes will push the
first of two cold fronts through our forecast area. Given the
moisture rich airmass that will be in place, the forcing from the
front will generate numerous showers and thunderstorms, most of
which will include pockets of heavy rain. The more widespread
activity found over the western counties through midnight, then east
of Lake Ontario during the second half of the night. A very warm and
humid night on tap with lows mainly in the mid and upper 60s once
again, although some cooler/less humid air will start to filter into
far western New York overnight behind the boundary.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
A pattern shift will occur late this week as a deep trough moves
into the Great Lakes region. Initially, a plume of moisture will be
positioned across northern and central New York Thursday morning. A
cold front will extend from low pressure over northern Ontario to
the New York City region, bisecting the eastern Great Lakes region.
Strong ascent from an approaching trough and high moisture content
ahead of a cold front will result in a high chance of moderate to
potentially heavy showers and thunderstorms across the eastern Lake
Ontario region Thursday morning. Drier air and weak cold air
advection will filter into the region behind the the cold front.
Mostly dry weather will begin across western NY Thursday morning.
Post frontal conditions with a trough overhead will result in
diurnally driven showers and thunderstorms across the region through
Thursday afternoon. A convergence zone across the lake plains is
likely with greater chances of showers from the Niagara Frontier to
the Finger Lakes region. The cold front will be east of the region
Thursday night and mostly dry weather is anticipated for most of the
night. There is a low chance of showers late Thursday night as a
secondary cold front moves across the region.

A closed low will become centered over central Ontario and central
Quebec Friday. A stretch of cooler weather (compared to earlier this
week) will begin Friday with 850mb temperatures falling to +4C by
Friday afternoon. A sharpening shortwave trough will move across the
region during peak heating hours Friday. Showers will blossom with a
slight chance of thunderstorms Friday afternoon. In fact, based off
the lake temperature at Buffalo (63F/17C,) lake enhancement is
possible, however the open water on Lake Erie and Lake Ontario is
much cooler. A moist, cyclonic flow will continue across the region
Friday night and with some lake enhancement, rain showers will
continue overnight.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
A large closed low pressure system aloft will wobble about the
eastern Great Lakes through at least the weekend before slowly
transitioning to New England early next week. This will maintain the
cool, unsettled pattern across the region with chances for showers
and thunderstorms. There are differences in shortwave troughs and
timing of showers even though the overall synoptic pattern is in
agreement.

Coverage and intensity will mainly follow the diurnal insulation
trend each day, generally being greatest in the afternoon hours and
away from any stabilizing influence from the lakes. There is
considerable disagreement with timing of waves of shortwave energy
around the low aloft. PWATs don`t look to become anomalously
elevated at any point which should preclude the develop of more
widespread impactful storm complexes. The one possible exception to
this may come as the system`s main trough axis and cold front drop
southward and generate some heavy rain across the region sometime in
the second half of the weekend, but at this juncture uncertainty is
high in this occurring.

As alluded to previously, temperatures will run below normal this
period. Highs Saturday and Sunday will only manage to top out in the
60s for most, though warm a few degrees for Monday and Tuesday with
low 70s becoming more common. Lows each night will mainly be in the
low/mid 50s, with upper 40s possible further inland away from the
influence of the lakes.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions will persist through at LEAST mid afternoon with just
a thickening and lowering of mid level decks from southwest to
northeast across western New York.

A few showers or an isolated storm will be found across western NY
late this morning and midday before more in the way of scattered
showers and storms are anticipated for the afternoon and early
evening hours.

As a cold front approaches and moves through tonight...more
widespread showers can be expected...along with some gusty
thunderstorms. The onset of the more widespread pcpn will include a
change to MVFR Cigs. IFR conditions will set up across the Srn Tier.

Outlook...

Thursday...Becoming mainly VFR with scattered showers and
thunderstorms, especially during the afternoon.
Friday through Sunday...VFR/MVFR with showers likely and possible
thunderstorms.

&&

.MARINE...
A southerly flow will strengthen today into tonight ahead of a slow
moving cold front approaching from the west. With the flow being
mainly offshore, the main impact will just be a bit of an uptick in
light chop toward the open waters.

The cold front will cross the lower Great Lakes late tonight and
Thursday morning, however expect a threat for thunderstorms this
afternoon through Thursday. SW to WSW winds will freshen on both
Lakes Thursday and 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 Thursday and
Friday afternoon, especially across eastern Lake Erie.

&&

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

&&

$$

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