597
FXUS61 KBUF 042219
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
619 PM EDT Wed Jun 4 2025

.SYNOPSIS...
Mid-summer heat expected today. A weak cold front will cross the
region Thursday with a round of scattered showers and thunderstorms.
The front will stall just south of the area, bringing additional
shower and thunderstorm chances through Saturday. High pressure will
build into the Great Lakes Sunday with a return to dry weather.

&&

.NEAR TERM /THROUGH THURSDAY/...
Latest satellite imagery shows mostly clear skies across western and
north-central NY, but farther west across MI extending southwest
down through IL/MO is increasing cloud cover from a cold front and
associated showers and thunderstorms this afternoon over the central
US. This will be the next system to move towards our region to
influence the weather late this week. Until then, warm weather
continues Wednesday afternoon with temperatures reaching the 80s and
a few spots approaching the 90 mark, likely being the warmest day
of the year so far.

Canadian wildfire smoke from fires well up in Saskatchewan and
Manitoba continues to be in place overhead across the eastern CONUS
and resulted in an Air Quality Alert for western NY today that
remains in effect through this evening.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
The cold front across the central CONUS will propagate into
western NY early Thursday with scattered rain showers in the
morning. Thunderstorms are expected to develop out ahead of the
cold front in the afternoon, likely along a line from the
Southern Tier extending northeastward across the Finger Lakes
and into the eastern Lake Ontario region with a Marginal Risk of
Severe Thunderstorms (SPC) and a Marginal Risk for Excessive
Rainfall (WPC). A weaker 500mb shortwave will pass in the flow
Friday with another round of showers and thunderstorms, mainly
across the Southern Tier. Showers will persist into early
Saturday before the weather begins to briefly dry out, but
temperatures will remain steady in the low to mid 70s for most.

Thunderstorm and Precipitation Potential: Environmental parameters
across the Southern Tier for Thursday afternoon highlight a warm
sector ahead of the cold front with unstable profiles, minimal
inhibition, and marginal wind profiles with 0-6 km shear around 30-
35 kt. HREF members are slightly more bearish with the HRRR only
producing 800-1300 J/kg of SBCAPE, but regardless enough for
thunderstorm development. This would be supportive of multicellular
convection along and ahead of the front that may be capable of brief
periods of strong outflow winds. Hi-res guidance would suggest
development in the early afternoon east and south of the I-90
corridor. Forecast soundings do highlight a drier layer aloft that
may promote hail growth, but the remainder of the profile is
relatively moist keeping the main hazard threat as gusty winds and
heavy rainfall. PW values will be hovering around the 90th
percentile value and any training convection across complex terrain
will need to be monitored for a localized flash flood threat. Latest
HREF PMM QPF does show values below but approaching the 3-hr FFG,
which is hovering around 2 inches. For Friday, shear will be weaker
as the mid-level flow maximum has moved off farther to the east and
a less sharp wave approaches from the west also supportive of slower
storm motions. This would limit strong to severe thunderstorm
potential, but excessive rainfall will still be possible over the
Southern Tier with moist profiles once again along the stalled east-
to-west front.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Generally quiet, seasonable weather Saturday night through at least
Sunday evening as a positively tilted 500mb trough axis translates
east of the region, with a progressive area of sfc high pressure in
its wake moving from the Great Lakes to New England coast. Broad
scale confluence and diurnal instability on the northwestern
periphery of low pressure extending further south off the Carolina
Coast could bring a few showers mainly to the eastern/southeastern
zones at times, though the vast majority of this period should be
dry.

The pattern will trend much more unsettled with a few rounds of
showers and potentially some afternoon thunderstorms as a large
vertically stacked low shifts east into the central Great Lakes
Monday, then weakens into an open wave and lifts into Quebec through
Tuesday. Behind the system`s cold front and primary trough axis
drier weather is expected, though temperatures are expected to
remain near seasonable levels through Wednesday.

&&

.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
For the 00Z TAFS, VFR flight conditions are found and these
conditions will persist for the next 9-12 hours. Showers from
upstream convection may near the northern Niagara Frontier in the
predawn hours.

The better chances for showers and thunderstorms, with locally gusty
winds, will come during the peak heating of the day tomorrow where
increasing instability and lift ahead of the cold front will blossom
storms, initially along a lake breeze boundary across the Southern
Tier and into the Genesee Valley and Finger Lakes region. Additional
storms are possible ahead of the front into the early evening hours.

While most of the second half of the period will feature VFR flight
conditions, any heavier shower or thunderstorm has the potential to
bring brief IFR/MVFR flight conditions. Towards the end of the
period and behind the front ceiling heights will begin to lower to
MVFR for higher elevations.

Outlook...

Thursday night higher elevation MVFR, lower elevation VFR; scattered
showers.

Friday...VFR/MVFR with showers likely and a chance of thunderstorms.

Saturday...MVFR with showers likely. Higher terrain IFR.

Sunday...Mainly VFR.

Monday...VFR/MVFR with showers possible.

&&

.MARINE...
High pressure will remain anchored off the eastern seaboard today.
Winds will remain relatively light in most areas. The one exception
will be on the western portion of Lake Ontario where moderate
southwesterlies will develop. The strongest winds and greatest wave
action will remain in offshore and Canadian waters.

A slow moving cold front will slide across the lower Great Lakes
tonight. Winds will become variable with the frontal passage and
eventually west/northwest winds at under 10 knots on Thursday.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Air Quality Alert until 11 PM EDT this evening for NYZ001-002-
     010>012-019-020-085.
MARINE...None.

&&

$$

SYNOPSIS...TMA
NEAR TERM...Brothers
SHORT TERM...Brothers
LONG TERM...PP
AVIATION...Thomas
MARINE...Hitchcock/TMA