Special Weather Statement, NWS Buffalo, NY

Area Forecast Discussion
National Weather Service Buffalo NY
755 AM EDT Wed Jul 29 2020

.SYNOPSIS...
A showery pattern for today and Thursday as an upper level low
pressure system to the north tracks away from the region. Dry
weather for Friday through Saturday evening before the next chance
for rain moves into the area Saturday night into Sunday.

&&

.NEAR TERM /THROUGH THURSDAY/...
An area of showers is moving into the WNY area this morning. Most of
the showers are widely scattered in nature, with a larger more
densely clustered area of showers over the western half of Lake
Ontario. As this area of showers continues to track east it will
slowly diminish in spatial coverage. Showers that do remain in tact
will track to the Genesee Valley and Northern Finger Lakes by mid
morning. A few embedded thunderstorms will be possible with this
area of showers. Current temperatures this morning are in the mid
60s to low 70s across the area.

Additional showers and thunderstorms will develop during the
afternoon and evening as a shortwave trough approach and cross the
region. A few strong to severe thunderstorms can't be ruled out as
instability increases through the day. Instability will be dependent
on how quickly cloud cover over the area can clear out after earlier
showers and thunderstorms, allowing for sunshine to increase
instability. Model guidance is suggesting CAPE values of around 1000
to as much as 1500 j/kg. Increasing shear through the afternoon will
also help with the potential for a few strong to severe
thunderstorms. Lapse rates are the primary factor limiting the
severe potential, with fairly weak rates from 3-6 km. Temperatures
today will be in the upper 70s to mid 80s.

Shower activity will continue tonight as the cold front crosses the
region and low level moisture, combined with cooling 850Ts to around
12C help to initiate a weak lake response. Temperatures tonight will
be in the low to mid 60s.

Thursday, the potential for scattered showers will continue as the
trough axis moves through the area. With 850Ts still around 12C for
the day, a lake response will still be possible downwind of both
lakes as well. Temperatures on Thursday will be in the mid 70s to
low 80s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
Weak cold front passage Thursday evening. Possibly cold enough in
its wake for lake clouds/sprinkles south shore of Lk Ontario late.

High pressure and confluent flow favors fair dry weather Friday and
Saturday. Shortwave approaches late Saturday night.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
A positively tilted trough spanning southward across the Northern
Great Lakes to the southeastern Plains will slowly lift
northeastward across the eastern third of the CONUS during the later
half of the weekend and into the first part of the work week. As
such, an associated surface low will track northeast across Lake
Erie and Lake Ontario Sunday, increasing chances for showers and
thunderstorms across the forecast region. With the departing surface
low and passage of the upper level trough axis will continue the
chances for showers/storms on Monday. A large area of surface high
pressure will dominate across the Great Lakes, spanning into the
region Tuesday which will promote dry weather for at least the
latter half of the day.

Temperatures for the later half of the weekend and the first couple
of days of the work week will range in the mid 70s to low 80s.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Mid level cloud cover will increase from west to east through the
morning as convection approaches from the west with a few showers
expected for far WNY this morning. Showers will push east and weaken
through mid-morning in the vicinity of KROC. Some clearing is
expected from west to east from the mid morning through early
afternoon before scattered showers and thunderstorms develop again
as a shortwave trough approaches from the west. Conditions will be
primarily VFR today, but brief periods of MVFR to IFR will be
possible with any heavier showers.

Mainly VFR tonight with a few showers possible through the night.

Outlook...

Thursday through Friday...Mainly VFR. Scattered showers especially
Thursday afternoon. River valley fog possible across the Western
Southern Tier early each morning. Saturday...VFR.
Sunday...MVFR/VFR with a chance of showers and thunderstorms.

&&

.MARINE...
A cold front will push across the Lower Great Lakes today.
Increasing southwest winds on Lake Erie for a few hours this
afternoon will approach Small Craft Advisory levels. Winds are
expected to be a but lighter on Lake Ontario.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory from 11 AM this morning to 5 PM EDT this
         afternoon for LEZ020-040-041.

&&

SYNOPSIS...SW
NEAR TERM...SW
SHORT TERM...RSH
LONG TERM...EAJ/RSH
AVIATION...SW
MARINE...SW

Special Weather Statement
National Weather Service Buffalo NY
1006 AM EDT Wed Jul 29 2020

NYZ001-010-019-020-085-291500-
Chautauqua-Cattaraugus-Southern Erie-Niagara-Northern Erie-
1006 AM EDT Wed Jul 29 2020

...A LINE OF SHOWERS WITH ISOLATED THUNDERSTORMS WILL AFFECT
NORTHERN CATTARAUGUS...ERIE...SOUTHERN NIAGARA AND NORTHEASTERN
CHAUTAUQUA COUNTIES...

At 1005 AM EDT, radar indicated showers with isolated thunderstorms
were located along a line extending from Niagara Falls to Evans.
Movement was east at 35 mph.

Winds in excess of 30 mph and pea size hail are possible with these
showers.

Locations impacted include...
Buffalo, Cheektowaga, Niagara Falls, West Seneca, North Tonawanda,
Clarence, Lockport, Lackawanna, Kenmore, Depew, Amherst, Tonawanda,
Lancaster, Hamburg, East Aurora, Williamsville, Grand Island, Evans,
Elma and Boston.

This includes Interstate 90 between exits 58 and 49.

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

LAT...LON 4259 7920 4264 7916 4273 7908 4280 7892
      4284 7893 4292 7890 4299 7902 4306 7900
      4308 7908 4314 7904 4318 7905 4324 7846
      4287 7848 4287 7849 4278 7849 4278 7846
      4252 7846 4252 7837 4245 7837 4244 7922
TIME...MOT...LOC 1405Z 262DEG 32KT 4311 7906 4267 7902

JLA