Flash Flood and Hail in New York, May 21, 2022

Area Forecast Discussion
National Weather Service Buffalo NY
316 PM EDT Sat May 21 2022

.SYNOPSIS...
Warm and humid conditions could yield a gusty afternoon thunderstorm
south and east of Buffalo and Rochester and also east of Lake
Ontario. Unsettled weather will become more widespread tonight
and especially Sunday...as a nearly stalled cold front will
finally plow through the region. Expansive high pressure will
support fair weather with cooler more comfortable conditions
Monday and Tuesday.

&&

.NEAR TERM /THROUGH SUNDAY/...
Early afternoon features mainly quiet conditions. A very strong line
of storms has recently crossed far western Lake Ontario with 65-70
GTA to the southwest. This line of storms continues to march east
and will clip the SLV in the next couple hours and possibly matching
up with storms developing recently to the east of Lake Ontario in
agitated cu field. Otherwise, capped cu has built up from Southern
Tier to Genesee Valley along and south of strong lake shadow off
Lake Erie. The cu field is within a strongly capped environment with
H7 temp of 11c leading to ample CINH, even as MLCAPES are 2-3k J/kg.
Effective shear away over much of the area is 30-35 kts. The capping
thus far is holding. A few storms tried to develop on the lake
breeze earlier from Erie PA to far western Chautauqua county, but
these faded rather quickly. As alluded to earlier Cu is becoming
more agitated from Southern Tier across Genesee valley to southeast
Lake Ontario region, so this also could be one initial location for
shra/tsra development. Are starting to see a few storms east of Lake
Ontario in this area as mentioned earlier.

Better chances for more organized thunderstorms appears like it is
going to wait til early this evening as widespread convective
shortwave over the western Ohio valley arrives from the west-
southwest. If this wave arrives early enough it will be able to
catch the tail end of the diurnal cycle and take advantage of the
strong instability built up and undisturbed over most of our region.
Prime time for widespread convection would be 21z-04z. Continue to
mention gusty winds and heavy rain given high PWATs over 1.3 inches
and potential for merging/training convection. The shortwave then
exits the region after midnight which should allow convection to
temporarily weaken/dissipate as we move through the overnight hours.
SPC continues to highlight entire area in slight risk for mainly
damaging winds and marginally severe hail.

Sunday will be rather unsettled throughout all of our forecast
area...as the stalled out cold front to the west will finally push
through the region from west to east with fairly widespread showers
and possible thunderstorms. Best chance for strong to severe storms
will be only the far eastern sections in the early afternoon.
Thunder over far western NY will be regulated to some rumbles of
thunder through midday. Temps will tumble post-frontal into the mid
50s to lower 60s western NY and into the 60s Genesee valley
eastward. Some models continue to suggest that the front will be
more anabatic in nature...which would favor more areas of just rain
rather than showers and storms, especially western NY. In either
case looks like quite a different day compared to the summertime
heat and humidity of today. Looking likely that the bulk of the day
will not be favorable for outdoor activities.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
Cooler and drier, a few showers will linger east of Lake Ontario
Sunday night but overall a fantastic start to the work week is on
tap.

Sfc high to our west will advance east passing by to our north on
Monday then off into the Canadian Maritimes on Tuesday. Below normal
highs expected Monday with low to mid 60s. With the departing sfc
high Tuesday, developing east to southeast flow will promote a warm
up into the 70s. One thing to keep an eye on will be overnight lows
Monday night...light winds and clear skies will 'likely' promote
good radiational cooling. The typical colder spots across the S.
Tier and east of Lake Ontario will potentially have to deal with
some frost. For now...will keep an eye on this potential.

Tuesday night...deepening low advancing out of Oklahoma and its warm
front extending east will bring low end chances for a few showers.
Otherwise...most locations will 'likely' see dry conditions
overnight.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Unsettled weather returns for the majority of the long term
portion of the forecast.

Wednesday into Thursday, a mid level ridge and surface high pressure
will slide eastward from New England and into the Northern Atlantic.
Meanwhile, a southern stream longwave trough digging across the
central Plains will slowly phase with a lower amplitude northern
stream trough, eventually forming a mid level closed low. The
associated surface low will deepen as it tracks northeast from the
Midwest across the Great Lakes region. This system will ultimately
bring a prolonged period of wet weather, with several shortwaves
rounding the base of the main trough as an attendant warm front
lifts through the region from the south, before slowly pushing a
cold front through the area from the west to close out the week.

In terms of more sensible weather, shower chances will increase from
west to east through the day Wednesday and into Wednesday evening as
one of the aforementioned shortwaves ejects northeast out ahead of
the approaching warm front. Shower activity will remain elevated
through Friday afternoon, with diurnal cycling generally expanding
coverage and introducing chances for a few thunderstorms in the
afternoon hours each day. Likewise, some breaks in the precip and
lower tstorm chances will be more common during the nighttime hours.
Western portions of the CWA will overall maintain higher shower
chances through the period in closer proximity to the track of the
shortwaves and the approaching cold front off to the west.

The main cold front will finally push through the region on Friday,
with the area slowly drying out from west to east by Friday night.
Saturday then looks to be mainly dry with clearing skies as a broad
upper level ridge builds in from the west.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
VFR conditions this afternoon. The possible exception will be across
the Southern Tier later this afternoon when if robust convection
develops it could produce short lived MVFR conditions for sites like
KJHW and KELZ.

MVFR cigs will become somewhat widespread during the course of
tonight as showers and storms will be found over parts of the
region. This will mainly be the case west of the Genesee valley as a
convective disturbance arrives to enhance the activity. Cigs will
likely further lower to IFR levels late tonight...especially across
the Southern Tier.

Outlook...

Sunday...MVFR to IFR with showers and thunderstorms.
Monday and Tuesday...Mainly VFR.
Wednesday...Mainly VFR with a chance of showers.
Thursday...MVFR to VFR. Showers and thunderstorms likely.

&&

.MARINE...
Moderate southwesterlies will be found throughout the Lower Great
Lakes this afternoon as a cold front remains stalled over southern
Ontario. While this will generate some choppy conditions on parts of
Lake Erie...small craft advisory conditions will not be met. It will
be close this afternoon though. There will be the risk for some
thunderstorms...especially this evening over Lake Erie and western
Lake Ontario. Mariners should pay attention for possible marine
warnings and/or statements for this activity.

Otherwise...the slow progression of the aforementioned cold front
through the Lower Great Lakes tonight will weaken the sfc pressure
and allow winds and waves to generally subside.

As the front pushes east of the region on Sunday and high pressure
builds in from the Upper Great Lakes...freshening winds and become
westerly. This will lead to choppy conditions on the eastern half of
Lake Ontario...but again...conditions for small craft advisories are
not expected to be met.

&&

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

&&

SYNOPSIS...JLA/RSH
NEAR TERM...JLA/RSH
SHORT TERM...AR
LONG TERM...PP
AVIATION...JLA/RSH
MARINE...JLA/RSH

Hazardous Weather Outlook
National Weather Service Buffalo NY
321 PM EDT Sat May 21 2022

NYZ001>005-010>014-019>021-085-221930-
Niagara-Orleans-Monroe-Wayne-Northern Cayuga-Northern Erie-Genesee-
Wyoming-Livingston-Ontario-Chautauqua-Cattaraugus-Allegany-
Southern Erie-
321 PM EDT Sat May 21 2022

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

.DAY ONE...This afternoon and tonight.

Thunderstorms may produce strong or damaging winds, hail, and heavy
rain late this afternoon through late this evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.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

NYZ006>008-221930-
Oswego-Jefferson-Lewis-
321 PM EDT Sat May 21 2022

...SEVERE THUNDERSTORM WATCH 256 IN EFFECT UNTIL 11 PM EDT THIS
EVENING...

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

.DAY ONE...This afternoon and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

A cold front crossing the region on Sunday will generate more
thunderstorms, some of which may be strong to severe. The main risk
with the stronger storms will be damaging wind gusts, marginally
severe hail and heavy rainfall.

.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-LOZ030-221930-
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-
321 PM EDT Sat May 21 2022

This Hazardous Weather Outlook is for portions of Lake Erie and Lake
Ontario.

.DAY ONE...This afternoon and tonight.

Thunderstorms may produce strong or damaging winds and hail late
this afternoon through late this evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Hazardous weather is not expected at this time.

.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

SLZ022-024-221930-
Saint Lawrence River from Cape Vincent to Ogdensburg-
Saint Lawrence River from Ogdensburg to Saint Regis-
321 PM EDT Sat May 21 2022

...SEVERE THUNDERSTORM WATCH 256 IN EFFECT UNTIL 11 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for the New York waters of the
Saint Lawrence River.

.DAY ONE...This afternoon and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Hazardous weather is not expected at this time.

.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

LOZ042>045-062>065-221930-
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-
321 PM EDT Sat May 21 2022

This Hazardous Weather Outlook is for portions of Lake Ontario.

.DAY ONE...This afternoon and tonight.

Thunderstorms may produce strong or damaging winds and hail early
this evening through early Sunday morning.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Hazardous weather is not expected at this time.

.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

JLA

Special Weather Statement
National Weather Service Buffalo NY
256 PM EDT Sat May 21 2022

NYZ010>013-019>021-085-212100-
Northern Erie-Genesee-Wyoming-Livingston-Chautauqua-Cattaraugus-
Allegany-Southern Erie-
Including the cities of Buffalo, Batavia, Warsaw, Geneseo,
Jamestown, Olean, Wellsville, Orchard Park, and Springville
256 PM EDT Sat May 21 2022

...THUNDERSTORMS MAY PRODUCE DAMAGING WINDS AND HEAVY RAINFALL
BETWEEN 6 PM AND MIDNIGHT...

Thunderstorms will develop along lake breeze boundaries late this
afternoon, and these will be followed by another line of storms
this evening. Storms which develop will have the potential to
produce damaging winds and heavy rainfall which may cause
localized flooding. The greatest risk for this weather to occur is
in between 6 p.m. and midnight. If you have outdoor plans during
these times, be prepared to seek shelter if threatening weather
approaches.

Apffel

Special Weather Statement
National Weather Service Buffalo NY
303 PM EDT Sat May 21 2022

NYZ006>008-212000-
Jefferson NY-Oswego NY-Lewis NY-
303 PM EDT Sat May 21 2022

...A strong thunderstorm will impact portions of southeastern
Jefferson, southwestern Lewis and northeastern Oswego Counties
through 400 PM EDT...

At 302 PM EDT, Doppler radar was tracking a strong thunderstorm near
Pulaski and moving northeast at 35 mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Fort Drum, Lowville, Pulaski, Adams, Redfield, Selkirk Shores State
Park, Mexico Point State Park, Barnes Corners, Whetstone Gulf State
Park, Richland, Mexico, Martinsburg, Black River, Greig, Rodman,
Orwell, Lorraine, Copenhagen, Sandy Creek and Lacona.

This includes Interstate 81 between exits 33 and 40.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4337 7607 4352 7629 4403 7579 4368 7534
TIME...MOT...LOC 1902Z 227DEG 32KT 4355 7604

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Reynolds