858
FXUS61 KBUF 201737
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
137 PM EDT Mon May 20 2024

.SYNOPSIS...
Summer-like warmth today through mid-week with a chance of a shower
or isolated thunderstorm well inland form the lakes. Better chances
for showers and thunderstorms arrive Wednesday into Thursday with
the arrival of a cold front. Dry and cooler Thursday night through
Saturday.

&&

.NEAR TERM /THROUGH TUESDAY/...
Summer-like warmth starts today. The mid-level ridge and surface
high pressure will slide east to the coast. Still looking like most
locales will stay dry, but a shower or storm will still be possible
on lake breeze boundary during peak heating. Temperatures about 10
to 15 degrees above normal with most highs in the lower to mid 80s.

Dry weather to continue for all locales tonight. Mild night with
lows found in the upper 50s to low 60s.

A convectively enhanced shortwave cutting through the mid-level
ridge may introduce a shower or thunderstorm by Tuesday morning.
After that, this feature may also help to induce a few more storms
inland from the lakes in the afternoon during peak heating.

Otherwise, a unseasonably warm day with temperatures firmly in the
80s. We might even see a few 90 degree readings in the Genesee
Valley. Warmest heat indices may be in the lower 90s.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
One last true summer-like day on tap Wednesday before a cold front
sweeps across the area later Wednesday night into Thursday morning
knocking temperatures back near normal on Thursday, from daytime
highs on Wednesday that will peak some 15 to 20 degrees above
average.

A remnant convective shortwave will pass by to our north Tuesday
night with associated activity expected to remain to our north,
while any lingering diurnally driven showers/isolated storms across
the interior Southern Tier/Finger Lakes quickly dissipate with the
loss of daytime heating. Meanwhile, the surface cold front that is
expected to cross western and northcentral NY later in the period
will be pressing east across Lake Michigan overnight, while its
associated low pressure system pulls northward across the Arrowhead
of Minnesota. It will be a very warm night with overnight lows
averaging in the mid 60s.

First half of Wednesday should be mainly dry before a prefrontal
trough in advance of the main cold front brings the likelihood for
showers and storms Wednesday afternoon and evening as it moves
across the region. This timeframe will be the best shot at our area
seeing a few stronger storms. Favorable timing will lend to plenty
of instability and there will be ample moisture to work with. One
factor that may hinder severe weather chances is the lack of
stronger wind fields aloft, as the better bulk shear at this time
looks like it may come into play a bit too late. That said, with the
robust available instability and deep moisture available, definitely
can`t rule some gusty winds with a few of the stronger storms. SPC`s
latest Day 3 Outlook has placed our area in a Marginal Risk at this
time. Will keep a mention in the HWO. Also, with PWAT values upwards
of 1.5 inches, heavy downpours will be possible, although decent
storm motion should keep flooding issues to a minimum. As with any
potential for a stronger convective event, this will need to be
monitored for any changes. Otherwise, although this will be the last
day, it will also likely be the warmest day of this summer-like
stretch with highs soaring into the mid and upper 80s for much of
the area, with a few 90 degree readings not out of the question in
those traditional warmest spots across the Genesee Valley and Finger
Lakes region. One caveat to achieving these very warm temperatures
would be if any precipitation were to arrive prior to peak heating,
with the best chance of that occurring across western NY.

There will be a break in the precipitation overnight Wednesday night
as the first round of showers and storms associated with the
prefrontal trough moves east and the next round of showers and
storms with the surface cold front approaches from the west. Main
threat with this second round of showers and storms will be some
heavy downpours as PWATs remain elevated. Unfavorable timing of the
frontal passage late Wednesday night and Thursday morning will keep
severe chances down, with drier air then moving into the area behind
the cold front Thursday afternoon. As was referenced above, a cooler
day on tap with highs ranging from the upper 60s to mid 70s, however
this is close to where we should be for this time of year.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Canadian high pressure will build across the region in the wake of
the cold fropa, with the majority of model consensus
(ECMWF/CMC/ICON) keeping our area dry through Sunday, the outlier
being the GFS which advertises some showers moving into the region
Saturday night and Sunday. NBM shows SChc to low Chc PoPs during
this timeframe as well, so at this point will hedge between a dry
forecast and the higher NBM/GFS PoPs for the second half of the
weekend.

The more notable aspect may end up being the degree to which we may
cool down for a bit during this period with a secondary cold front
crossing the region. Not only is the timing of this potential cool
down still in question, but also is the magnitude of colder air that
could potentially make it in here. The main reason for this is the
discrepancy amongst guidance with regard to just how deep an upper
level trough may possibly dig across the northeastern U.S. As of
now, temperatures may end up a little below normal for a short time
in this window, but will not last long. All in all, very comfortable
later spring conditions.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Widespread VFR conditions with light winds through this afternoon.
High based (above 5K feet), mostly scattered cu field developing
inland from the lakes this afternoon. Potential exists for some
widely scattered convection after 19z which is suggested by both the
HREF and HRRR from the interior Southern Tier into the Finger
Lakes. Confidence is low in exact coverage of any convection, with
any convection which does develop likely remaining south and east of
KROC and KJHW.

Tonight...VFR expected at all area terminals.

Outlook...

Tuesday...Mainly VFR. A chance of showers or a thunderstorm.
Wednesday...VFR/MVFR. Showers and thunderstorms likely.
Thursday...Mainly VFR. A chance of showers.
Friday and Saturday...Mainly VFR.

&&

.MARINE...
Light winds with minimal wave action expected on Lake Erie and Lake
Ontario through tonight.

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 into
the eastern Great Lakes.

&&

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

&&

$$

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