588
FXUS61 KBUF 171806
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
206 PM EDT Sun May 17 2026

.WHAT HAS CHANGED...
No significant changes with this update.

&&

.KEY MESSAGES...
1) Summer-like heat Monday through Tuesday.

2) Spotty showers and thunderstorms possible late today through
Monday, but dry most of the time.

3) A strong cold front will bring numerous showers and
thunderstorms late Tuesday eve into Wednesday.

4) Drier and cooler conditions behind the front Wednesday
through Friday, unsettle weather potentially returns for the
weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Summer-like heat Monday through Tuesday.

An early taste of mid-summer heat will build into the region Monday
through Tuesday, with by far the warmest airmass of the spring to
this point. 850MB temps will soar to near +17C Monday afternoon
through Tuesday as a strong mid level ridge builds to the eastern
seaboard and allows a thermal ridge to advect into the eastern Great
Lakes. Highs will reach the 85-90 degree range both Monday and
Tuesday afternoon away from lake influences. Overnight lows Monday
night will also be very warm by May standards, in the mid to upper
60s.

Dewpoints will generally run in the upper 50s to lower 60s in most
areas, possibly as high as the mid 60s on the lake plains. These
values are not high enough to produce any appreciable heat index
above the ambient air temperature.

KEY MESSAGE 2...Spotty showers and thunderstorms possible late today
through Monday, but dry most of the time.

Dry weather will prevail most of the time this afternoon through
Monday, with a few minor exceptions.

Visible satellite imagery shows an agitated cumulus field across the
higher terrain of the western Southern Tier this afternoon. High-res
CAMS guidance continues to suggest a few spotty showers and
thunderstorms may develop across the western Southern Tier later
this afternoon and evening. Coverage of this convection will be
sparse, if it develops.

Tonight, a warm frontal segment will move quickly northeast across
the Great Lakes, supported by a convectively augmented mid level
shortwave. The most active portion of this warm front is forecast to
move from near Lake Huron late this evening to the Ottawa Valley by
Monday morning, where forcing and moisture is maximized. There is
considerable uncertainty with the southern extent of showers and
thunderstorms along the warm front, but some of the 12Z model
guidance has trended wetter as far south as over and near Lake
Ontario. With this in mind, increased POPS from the previous
forecast down to near the NYS Thruway to account for the potential
overnight warm frontal convection. The last of this activity will
exit the North Country by mid morning Monday.

The rest of Monday will be mainly dry, although an isolated shower
or thunderstorm cannot be ruled out late afternoon and early evening
with peak heating and diurnal instability. If this occurs, it would
be mainly across the Southern Tier, Finger Lakes, and/or southern
Tug Hill region away from the stabilizing influence of southwest
flow over and northeast of Lake Erie and Lake Ontario.

KEY MESSAGE 3...A strong cold front will bring numerous showers
and thunderstorms late Tuesday eve into Wednesday.

The main challenge with this update will be timing of a strong cold
front approaching the Lower Lakes for later Tuesday eve. That
said...lets backing up a bit and talk about Monday night, Hi-res
guidance continues to suggest a convectively enhanced shortwave
ripping across Michigan on the fringes of the mid-level ridge. While
it appears that most of the convection with this feature will weaken
as it nears, a few showers or even an isolated storm could sneak
into the region overnight into Tuesday morning. Have added `low` end
PoPs (< 25%) to account for this feature given so much uncertainty
to how it will impact our area. Moving on...the next feature of
concern is the incoming shortwave trough and arrival (timing) of a
strong cold front for Tuesday eve and night. While there may be some
storms that pop Tuesday afternoon given plenty of advertised CAPE
(+2K j/kg), especially along lake breeze boundaries, more numerous
showers and storms is anticipation with the front. SPC has place
much of the area in a Marginal Risk (12Z Tuesday-12Z Wednesday)for
the potential for severe storms with the main threat damaging wind
gusts.

KEY MESSAGE 4...Drier and cooler conditions return behind the
front Wednesday afternoon through Friday, unsettle weather
potentially returns for the weekend.

Surface based ridging will begin to build into the Great Lakes
region Wednesday behind the front with drier weather and cooler
conditions. The coolest day of the week still looks to be Thursday
where highs will be found in the 50s to low 60s in the warmest
locales. After Thursday...a day to day warming trend begins which
last into the weekend, we also could see increasing chances for
showers.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
The last of the MVFR stratus across the higher terrain of the
Southern Tier and east of Lake Ontario will evolve into cumulus
fields this afternoon with bases improving to VFR. Dry weather will
prevail in most areas, although a few isolated showers and
thunderstorms may briefly develop across the western Southern Tier
later this afternoon and early evening.

Tonight, a warm front will move northeast across the area. The most
active portion of the warm front is forecast to move from Lake Huron
across southern Ontario overnight. The southern end of showers and
scattered thunderstorms along and ahead of the warm front may clip
areas near the Canadian border, supporting the chance of a brief
period of showers and thunder across most of the terminals
overnight. Otherwise, VFR will prevail outside of any showers.

A low level jet will move across the eastern Great Lakes late
tonight through Monday morning, supporting a period of low level
wind shear.

Monday, the last of the potential warm frontal showers and
thunderstorms will exit the eastern Lake Ontario region early in the
morning. This will leave mainly dry conditions and VFR for the rest
of the day. There is a very low end chance of an isolated shower or
thunderstorm late in the day from the Southern Tier through the
Finger Lakes to the southern Tug Hill Plateau. Winds will gust in
the 20-30 knot range across the Niagara Frontier from late morning
through the afternoon.

Outlook...

Tuesday..Mainly VFR. A chance of a few showers and thunderstorms
later in the afternoon.

Tuesday night through Wednesday...Areas of MVFR/local IFR with
showers and thunderstorms, ending from west to east and improving to
VFR Wednesday morning.

Thursday through Friday...VFR.

&&

.MARINE...
The pressure gradient will gradually tighten across the lower Great
Lakes Monday through Tuesday. Moderate southwesterlies will bring
very choppy conditions to the west end of Lake Ontario by Monday
afternoon, with lighter winds elsewhere.

Winds will increase further on Tuesday ahead of an approaching cold
front. Winds and waves will likely support Small Craft Advisory
conditions by afternoon on the western portion of Lake Ontario, with
the stronger winds and greater wave action then spreading east to
the east end of Lake Ontario later Tuesday night through Wednesday
as the cold front crosses the lake. Winds on Lake Erie will be
somewhat lighter, but still strong enough to produce a moderate chop
Tuesday through Wednesday.

&&

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

&&

$$

DISCUSSION...AR/Hitchcock
AVIATION...Hitchcock
MARINE...Hitchcock