Severe Thunderstorm Warning 20, NWS Buffalo, NY

Area Forecast Discussion
National Weather Service Buffalo NY
240 PM EDT Wed Apr 15 2026

.WHAT HAS CHANGED...
The severe thunderstorm threat has again slightly increased across
the Southern Tier late this afternoon and this evening.

&&

.KEY MESSAGES...
1) Warm with rounds of showers and thunderstorms through Thursday.

2) Severe thunderstorms remain possible through Thursday, with
locally heavy rainfall also possible through tonight.

3) The very warm pattern continues through Saturday before much
colder air arrives by early next week.

&&

.DISCUSSION...
KEY MESSAGE 1...Warm with rounds of showers and thunderstorms
through Thursday.

Our unsettled pattern will continue through Thursday with a
persistent frontal zone remaining in place across the Great Lakes
and Northeast...with multiple shortwave impulses (some convectively
enhanced) and their associated surface reflections rippling
northeastward along the frontal zone and causing it to waver
about...while also generating additional rounds of showers and
thunderstorms.

Currently our region is in between rounds of convection...with the
all-but-dead remnants of some earlier upstream showers/storms
crossing the Niagara Frontier in the form of some sprinkles or very
light showers. As we push through the rest of this afternoon the
combination of increasing diurnal instability and localized
convergence along the southern edge of the Lake Erie lake breeze may
allow for some scattered to briefly numerous showers and storms to
initially develop across the southern Tier and interior of the
Finger Lakes...before an upstream MCV (currently over Indiana)
begins encroaching upon the area from the southwest early this
evening. Better forcing attendant to this feature will combine with
lingering instability to produce a round of numerous to fairly
widespread showers and storms across areas south of the NYS Thruway
during the early to mid evening hours...with the areal coverage of
the pcpn/pcpn potential diminishing with further northward extent
elsewhere.

Following the passage of the MCV...we'll likely experience another
relative lull in convective potential through the late evening and
early overnight hours...with some additional warm advection-driven
showers and scattered storms then possible overnight into early
Thursday in association with another wave of low pressure making its
way into the central Great Lakes and its attendant warm front. With
the latter...have confined PoPs to likely or lower for now given the
poorer agreement on the timing/placement of convection seen in the
shorter-term guidance.

Thursday and Thursday evening...the aforementioned surface wave and
its parent mid-level shortwave trough will make their way east and
across our region...and in the process will push the frontal
boundary southeastward across our region as a cold front during the
afternoon and evening. With modest to moderate instability
developing out ahead of the front...the combination of low level
convergence along the front/localized lake breeze boundaries and
DCVA/height falls aloft should have little trouble generating
another round of fairy widespread showers and thunderstorms during
the afternoon and early evening hours...with the convection then
fading from NW-SE during the evening with the loss of heating and
the passage of the cold front. This system will then depart off to
our east later Thursday night and Friday...with any leftover spotty
showers at the start of Friday giving way to a mainly dry and
somewhat cooler day (though temps will still be well above normal)
as narrow ridging both at the surface and aloft builds across our
region.

KEY MESSAGE 2...Severe thunderstorms remain possible in some areas
through Thursday, with locally heavy rainfall also possible.

Through Thursday/Thursday evening there will be two main windows for
potentially strong to severe thunderstorms. The first of these will
be this evening south of the NYS Thruway (more so across the
Southern Tier) in association with passage of the above mentioned
MCV. Provided enough of a reservoir of instability remains to allow
the stronger convection with this feature to extend northward into
our area...the accompanying stronger forcing/increased shear may be
supportive of a few strong to damaging wind gusts...as well as a
lower but nonzero potential for marginally severe hail and/or an
isolated tornado.

The second opportunity for strong to severe thunderstorms will be
Thursday afternoon and evening...in tandem with the approach/passage
of the main shortwave trough/cold front and an accompanying enhanced
swath of low-mid level flow. With modest to moderate instability
likely to develop across the region out ahead of the cold front
(particularly from the Genesee Valley/Finger Lakes eastward into
central NY)...the dynamic/kinematic forcing from the above features
should be sufficient for at least some stronger multicellular
convection and possibly even a few supercells...with damaging wind
gusts again the primary hazard. This being said...large hail and an
isolated tornado or two again cannot be ruled out...particularly
from the Genesee Valley/Finger Lakes eastward to central NY where
instability should be greater.

Finally...there will also be a lower-end potential for excessive
rainfall/flooding through Thursday given the moist ground conditions
and PWATs of 1.25/1.5"...though given the fast flow aloft and
resultant expected quick storm motion this would likely only be a
concern if any areas of training were to develop.

KEY MESSAGE 3...The very warm pattern continues through Saturday
before much colder air arrives by early next week.

Well above normal temperatures will continue through Saturday as
our region will remain in the warm sector of a deepening trough over
the Upper Great Lakes/an associated surface low making its way to
near James Bay. Temperatures will soar into at least the mid to
upper 70s...with 80s a possibility if clouds and showers hold off
long enough. The strong cold front trailing from the low will then
plow across our region late Saturday afternoon and night while
generating another round of widespread showers and thunderstorms...
some of which could be severe depending upon the exact timing of the
front/amount of instability in place.

In the wake of this front...deep upper level troughing and a much
colder airmass will overspread our region Sunday through Monday...
with 850 mb temps plunging into the -10C to -14C range by late
Sunday night/early Monday. This will rudely send temperatures back
down to levels more typical of March...with the cold airmass and
northwest flow regime also supporting lake effect and upslope snow
showers in a northwest flow regime Sunday night through Monday
morning. This being said...moisture appears limited and the
favorable synoptic scale setup is rather brief, so any accumulations
will be minor. Highs Monday will only be in the upper 30s/lower 40s
at best, and may stay in the 30s areawide if clouds persist most of
the day.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Heading into the afternoon, lingering low level clouds persist
across the eastern Lake Ontario region this afternoon, supporting
the only IFR conditions region. Otherwise in the wake of this
morning's line of thunderstorms, conditions across the remainder of
the area have improved to VFR, supporting destabilization and gusty
winds with southwest to westerly winds gusting between 25 to 35
knots across Western New York and the Genesee Valley.

The next round of convection will move in from west to east in the
next few hours, with the best timing of arrival being around 21Z. A
few thunderstorms may become severe, with the best location for
severe weather lying between KJHW to KELZ. Storms across the
Southern Tier will likely produce severe gusts. Additionally an
isolated tornado can't be ruled our and a lesser chance for severe
hail. Showers and storms will likely remain within the vicinity of
the Southern Tier tonight, with ceilings to deteriorate to IFR
areawide.

Outlook...

Thursday and Thursday night...VFR/MVFR with some local IFR possible
at times due to numerous rounds of showers and scattered
thunderstorms.

Friday...VFR/MVFR with showers possible.

Saturday...Mainly VFR with a chance for showers later in the
afternoon.

Sunday...A mixture of MVFR/IFR with rain showers mixing with and
changing over to snow throughout the day.

Monday...Improving to VFR/MVFR. Lingering lake enhanced snow showers
and clouds gradually dissipate.

&&

.MARINE...
Multiple rounds of showers and thunderstorms will cross the lakes
through Thursday, a few of which may produce strong surface wind
gusts and locally higher waves. Otherwise the warmer airmass and
relatively cold lake temperatures will result in limited mixing of
synoptic winds...thereby precluding any real risk of advisory-level
conditions.

Relatively light winds and minimal wave action are then expected
later Thursday night and Friday as high pressure builds across the
Lower Great Lakes...before winds increase out of the south/southwest
Saturday/Saturday night in association with the approach/passage of
a strong cold front. This may result in the next round of SCA
conditions with the frontal passage also accompanied by another
round of showers and storms...some of which could produce locally
stronger winds and higher waves.

&&

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

&&

DISCUSSION...JJR
AVIATION...EAJ
MARINE...JJR

Hazardous Weather Outlook
National Weather Service Buffalo NY
243 PM EDT Wed Apr 15 2026

NYZ010>014-019>021-085-161845-
Northern Erie-Genesee-Wyoming-Livingston-Ontario-Chautauqua-
Cattaraugus-Allegany-Southern Erie-
243 PM EDT Wed Apr 15 2026

This Hazardous Weather Outlook is for portions of western New York.

.DAY ONE...This afternoon and tonight.

Another second round of thunderstorms is expected late this
afternoon and evening, with a greater chance of severe thunderstorms
across the Southern Tier. The primary severe weather risk will be
isolated damaging wind gusts, with a secondary lower risk of large
hail and an isolated tornado.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Additional rounds of showers and scattered thunderstorms will cross
the region Thursday. Some of these storms may become severe. The
primary severe weather risk will be isolated damaging wind gusts,
with a secondary lower risk of large hail and an isolated tornado.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

This product, along with other watches, warnings, advisories, and
statements issued by the National Weather Service office in Buffalo
can be found on the internet at http://www.weather.gov/buf

NYZ001>008-161845-
Niagara-Orleans-Monroe-Wayne-Northern Cayuga-Oswego-Jefferson-Lewis-
243 PM EDT Wed Apr 15 2026

This Hazardous Weather Outlook is for portions of western and north
central New York.

.DAY ONE...This afternoon and tonight.

A second round of showers and thunderstorms is possible late this
afternoon and this evening, but the greater severe weather risk will
likely remain south of the NYS Thruway.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Additional rounds of showers and scattered thunderstorms will cross
the region Thursday. Some of these storms may become severe. The
primary severe weather risk will be isolated damaging wind gusts,
with a secondary lower risk of large hail and an isolated tornado.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

This product, along with other watches, warnings, advisories, and
statements issued by the National Weather Service office in Buffalo
can be found on the internet at http://www.weather.gov/buf

LEZ020-040-041-LOZ030-042>045-062>065-SLZ022-024-161845-
Upper Niagara River and Buffalo Harbor-
Lake Erie nearshore waters from Ripley to Dunkirk-
Lake Erie nearshore waters from Dunkirk to Buffalo-
Lower Niagara River-
Lake Ontario nearshore waters from the Niagara River to Hamlin Beach-
Lake Ontario nearshore waters from Hamlin Beach to Sodus Bay-
Lake Ontario nearshore waters from Sodus Bay to Mexico Bay-
Lake Ontario nearshore waters from Mexico Bay to the Saint Lawrence
River-
Lake Ontario open waters from the Niagara River to Hamlin Beach-
Lake Ontario open waters from Hamlin Beach to Sodus Bay-
Lake Ontario open waters from Sodus Bay to Mexico Bay-
Lake Ontario open waters from Mexico Bay to the Saint Lawrence River-
Saint Lawrence River from Cape Vincent to Ogdensburg-
Saint Lawrence River from Ogdensburg to Saint Regis-
243 PM EDT Wed Apr 15 2026

This Hazardous Weather Outlook is for the New York waters of Lake
Erie, Lake Ontario, and the Saint Lawrence River.

.DAY ONE...This afternoon and tonight.

Another round of showers and thunderstorms is expected late this
afternoon and evening, with a greater chance of severe thunderstorms
across Lake Erie. The primary severe weather risk will be isolated
damaging wind gusts and locally higher waves, with a secondary lower
risk of large hail and an isolated tornado.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Additional rounds of showers and scattered thunderstorms will cross
the region Thursday. Some of these storms may become severe. The
primary severe weather risk will be isolated strong wind gusts and
locally higher waves, with a secondary lower risk of large hail and
an isolated tornado.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

This product, along with other watches, warnings, advisories, and
statements issued by the National Weather Service office in Buffalo
can be found on the internet at http://www.weather.gov/buf

JJR