Special Weather Statement, NWS Buffalo, NY

Area Forecast Discussion
National Weather Service Buffalo NY
925 AM EDT Sun Aug 1 2021

.SYNOPSIS...
A cold front and area of low pressure will cross the region today
with occasional showers and scattered thunderstorms, where a few
storms may contain locally heavy downpours and gusty winds.
Scattered showers will linger tonight before high pressure builds
into the eastern Great Lakes Monday, bringing a return to dry
weather that will last much of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A mid-level trough will move from the central Great Lakes this
morning to the eastern Great Lakes by early evening, all while
sharpening and digging with time as an additional shortwave and jet
max dive into the western side of the trough. A cold front will
advance east across the eastern Great Lakes in the afternoon as a
weak wave of low pressure runs northeast along the boundary and
crosses NY. Increasing large scale ascent ahead of the mid level
trough, convergence and moisture transport from the wave of low
pressure, and PWAT values rising to around 1.3" will support
widespread showers and scattered thunderstorms.

Radar imagery showing areas of showers and a few widely scattered
thunderstorms across much of the region this morning. Showers and
scattered thunderstorms will continue to gradually increase in
coverage from west to east from late morning through early
afternoon. The early arrival of clouds and showers will inhibit
destabilization, and deep layer shear remains quite weak with only
25-30 knots effective shear at best. This will limit the severe
weather potential, although strong forcing from the mid-level trough
and surface wave may compensate to some extent and support a
marginal risk of a few isolated strong wind gusts. SPC recently
included a slight risk for Central NY and portions of PA, but this
relatively greater risk is expected to remain largely east of our
forecast area. Some storms will also contain locally heavy rainfall,
but the progressive eastward advance of forcing should keep storms
moving and limit flood potential.

The first area of showers and storms will taper off from west to
east during late afternoon and evening. Abundant wrap around
moisture and developing northwest upslope flow coupled with the mid
level trough passage will continue to support some showers Sunday
night. The airmass is cool enough aloft to allow some lake
enhancement as well southeast of the lakes. There may still be a few
widely scattered thunderstorms in the evening, with thunder chances
ending by midnight as instability wanes. Showers will gradually
taper off late Sunday night from west to east.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The main upper trough axis will shift eastward into the Canadian
Maritimes Monday. A few leftover showers will be possible Monday
morning across north central New York, otherwise expect a drying
trend through the day as subsidence develops behind the trough.
Temperatures will continue to be below normal, although there will
be increasing sunshine. Highs in the lower to mid 70s

Fair and cool Monday night with most lows in the 50s, with upper 40s
across the interior sections of the Southern Tier and North Country.

Fair weather will continue Tuesday and Tuesday night with high
pressure over the region. Temperatures getting a boost with most
highs Tuesday in the mid to upper 70s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
In the extended portion of the forecast...a modest upper level low
over the Ohio Valley Wednesday will weaken and slowly drift
northeast to New York State and New England through the balance of
the work week...with broad/weak upper level troughing then lingering
across our region into next weekend.

With respect to precipitation chances...weak impulses circulating
through the resultant general troughiness across our region will
combine with slowly building warmth and humidity to yield the
potential for a few widely scattered to scattered showers/storms
each day...with these mainly coming during the afternoon/early
evening hours in concert with peak daytime heating. This said...
much of the time should remain rain free.

Otherwise...both temperatures and humidity levels will be on a
gradual increase through this period...with daytime highs and
surface dewpoints respectively reaching the low-mid 80s and low-mid
60s by next week Friday and Saturday.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
A mid level trough, cold front, and wave of low pressure will cross
the eastern Great Lakes, with occasional showers and scattered
thunderstorms through this evening. CIGS/VSBY will deteriorate to
MVFR as the more widespread showers develop. Any IFR will likely be
brief and localized in heavier showers or thunderstorms.

The first round of showers and scattered storms will taper off from
west to east later this afternoon and evening. A few showers will
linger overnight, especially southeast of Lake Ontario with some
enhancement from the lake. Fairly widespread MVFR CIGS will continue
tonight, with some IFR across higher terrain.

Outlook...

Monday...Leftover early morning low CIGS improving to VFR.
Tuesday through Thursday...VFR.

&&

.MARINE...
A cold front will cross the eastern Great Lakes today, with
occasional showers and scattered thunderstorms. A few storms may
contain gusty winds.

Conditions will become more favorable for waterspouts late this
morning through tonight as a cold pool aloft moves over the eastern
Great Lakes, steepening low level lapse rates and allowing lake
induced equilibrium levels to rise to around 30K feet. The latest
model forecast from the ICWR continues to support this potential.

Northwest winds will increase tonight through Monday morning in the
wake of this system, resulting in very choppy conditions along the
south shore of Lake Ontario. Latest model guidance suggests winds
and waves will remain just below Small Craft Advisory levels.

&&

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

&&

SYNOPSIS...EAJ/Hitchcock
NEAR TERM...EAJ/Hitchcock
SHORT TERM...TMA
LONG TERM...JJR
AVIATION...EAJ/Hitchcock
MARINE...EAJ/Hitchcock

Hazardous Weather Outlook
National Weather Service Buffalo NY
503 AM EDT Sun Aug 1 2021

NYZ001>008-010>014-019>021-085-020915-
Niagara-Orleans-Monroe-Wayne-Northern Cayuga-Oswego-Jefferson-Lewis-
Northern Erie-Genesee-Wyoming-Livingston-Ontario-Chautauqua-
Cattaraugus-Allegany-Southern Erie-
503 AM EDT Sun Aug 1 2021

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

.DAY ONE...Today and tonight.

There is a marginal risk for severe thunderstorms through early this
evening. The primary threat is damaging wind gusts. Heavy rainfall
may cause localized flooding.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

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

LEZ040-041-LOZ042>045-062>065-020915-
Lake Erie nearshore waters from Ripley to Dunkirk-
Lake Erie nearshore waters from Dunkirk to Buffalo-
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-
503 AM EDT Sun Aug 1 2021

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

.DAY ONE...Today and tonight.

There is a marginal risk for severe thunderstorms through early this
evening. The primary threat is damaging wind gusts.

There is a chance of waterspouts.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

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

LEZ020-LOZ030-020915-
Upper Niagara River and Buffalo Harbor-Lower Niagara River-
503 AM EDT Sun Aug 1 2021

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

.DAY ONE...Today and tonight.

There is a marginal risk for severe thunderstorms through early this
evening. The primary threat is damaging wind gusts.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

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

SLZ022-024-020915-
Saint Lawrence River from Cape Vincent to Ogdensburg-
Saint Lawrence River from Ogdensburg to Saint Regis-
503 AM EDT Sun Aug 1 2021

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

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

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

Special Weather Statement
National Weather Service Buffalo NY
730 AM EDT Sun Aug 1 2021

NYZ085-011215-
Southern Erie-
730 AM EDT Sun Aug 1 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN ERIE COUNTY...

At 729 AM EDT, a strong thunderstorm was located over North Collins,
or 9 miles southwest of Hamburg, moving east at 20 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm, along with torrential downpours.

Locations impacted include...
Evans, Boston, Eden, Angola, North Collins, Evangola State Park,
Angola on the Lake, Derby, and North Boston.

This includes Interstate 90 near exit 57A.

Torrential rainfall is occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4264 7916 4267 7912 4269 7910 4272 7872
      4256 7868 4255 7899 4259 7919
TIME...MOT...LOC 1129Z 265DEG 16KT 4263 7896

Hitchcock

Special Weather Statement
National Weather Service Buffalo NY
955 AM EDT Sun Aug 1 2021

NYZ013-014-011430-
Ontario-Livingston-
955 AM EDT Sun Aug 1 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN LIVINGSTON AND
SOUTHWESTERN ONTARIO COUNTIES...

At 954 AM EDT, a strong thunderstorm was located over Dansville,
moving northeast at 30 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm, along with brief torrential downpours.

Locations impacted include...
Dansville, Naples, Springwater and Hunt Hollow.

This includes Interstate 390 between exits 4 and 5.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4248 7776 4262 7777 4273 7734 4267 7737
      4258 7737 4258 7766 4254 7766 4253 7767
      4253 7772 4250 7772
TIME...MOT...LOC 1354Z 242DEG 27KT 4258 7763

Hitchcock

Special Weather Statement
National Weather Service Buffalo NY
1008 AM EDT Sun Aug 1 2021

NYZ019-020-085-011445-
Chautauqua-Cattaraugus-Southern Erie-
1008 AM EDT Sun Aug 1 2021

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHWESTERN
CATTARAUGUS...SOUTHWESTERN ERIE AND NORTHERN CHAUTAUQUA COUNTIES...

At 1007 AM EDT, radar indicated strong thunderstorms were located
along a line extending from near Silver Creek to 6 miles east of
North East. Movement was east at 35 mph.

Winds in excess of 30 mph and pea size hail are possible with these
storms, along with brief torrential downpours.

Locations impacted include...
Fredonia, Westfield, Gowanda, Mayville, Chautauqua Institution,
Concord, Collins, Portland, Sheridan, Ripley, Stockton, Gerry,
Dayton, Brocton, Arkwright, Forestville, Cassadaga, South Dayton and
Sinclairville.

Torrential rainfall is also occurring with these storms, and may
cause localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4257 7866 4218 7925 4224 7975 4254 7915
TIME...MOT...LOC 1407Z 260DEG 31KT 4250 7908 4222 7971

Hitchcock

Special Weather Statement
National Weather Service Buffalo NY
1011 AM EDT Sun Aug 1 2021

NYZ012-013-020-021-011445-
Cattaraugus-Allegany-Livingston-Wyoming-
1011 AM EDT Sun Aug 1 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTHERN WYOMING...NORTHEASTERN
CATTARAUGUS...SOUTHWESTERN LIVINGSTON AND NORTHWESTERN ALLEGANY
COUNTIES...

At 1010 AM EDT, a strong thunderstorm was located near Lime Lake,
moving east at 35 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm, along with brief torrential downpours.

Locations impacted include...
Letchworth State Park, Arcade, Franklinville, Rushford, Houghton,
Portageville, Yorkshire, Caneadea, Eagle, Pike, Delevan, Castile,
Short Tract, Fillmore, Lime Lake, Bliss, Hunt, Rossburg, and Dalton.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4252 7854 4253 7847 4255 7846 4263 7803
      4251 7790 4236 7799 4234 7854
TIME...MOT...LOC 1410Z 260DEG 31KT 4245 7842

Hitchcock

Special Weather Statement
National Weather Service Buffalo NY
1044 AM EDT Sun Aug 1 2021

NYZ012-019-020-085-011530-
Chautauqua-Cattaraugus-Southern Erie-Wyoming-
1044 AM EDT Sun Aug 1 2021

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SOUTHWESTERN WYOMING...
NORTHWESTERN CATTARAUGUS...SOUTHEASTERN ERIE AND SOUTHERN CHAUTAUQUA
COUNTIES...

At 1043 AM EDT, radar indicated strong thunderstorms were located
along a line extending from near Gowanda to near Findley Lake.
Movement was east at 20 mph.

Winds in excess of 30 mph and pea size hail are possible with these
storms, along with brief torrential downpours.

Locations impacted include...
Jamestown, Springville, Lakewood, Gowanda, Falconer, Arcade,
Mayville, Chaffee, Ashford Hollow, Chautauqua Institution, Findley
Lake, East Concord, Frewsburg, Concord, Collins, Yorkshire and
Sardinia.

This includes Interstate 86 between exits 4 and 16.

Torrential rainfall is also occurring with these storms, and may
cause localized flooding. Do not drive your vehicle through flooded
roadways.

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 4234 7919 4256 7890 4265 7835 4222 7875
      4204 7922 4211 7976 4215 7976
TIME...MOT...LOC 1443Z 265DEG 15KT 4251 7888 4213 7968

Hitchcock

Special Weather Statement
National Weather Service Buffalo NY
1047 AM EDT Sun Aug 1 2021

NYZ013-021-011530-
Allegany-Livingston-
1047 AM EDT Sun Aug 1 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL LIVINGSTON AND
NORTHERN ALLEGANY COUNTIES...

At 1046 AM EDT, a strong thunderstorm was located over Houghton, or
19 miles southwest of Letchworth State Park, moving east at 30 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm, along with brief torrential downpours.

Locations impacted include...
Belfast, Rushford, Houghton, Caneadea, Ossian, Canaseraga, Almond,
Birdsall, Short Tract, Ossian Center, Fillmore and Swain.

This includes Interstate 86 near exit 33.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

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 4235 7828 4245 7828 4257 7772 4246 7772
      4246 7773 4231 7774
TIME...MOT...LOC 1446Z 260DEG 24KT 4240 7817

Hitchcock