Special Weather Statement, NWS Buffalo, NY

Area Forecast Discussion
National Weather Service Buffalo NY
159 AM EDT Tue Jul 13 2021

.SYNOPSIS...
A deep southerly flow of moisture rich air will yield occasional
bouts of showers and thunderstorms across our region through at
least the first half of this week. This will include the continued
risk for tropical downpours and gusty winds, especially in the
afternoon and early evening hours. After a brief break in the
unsettled weather on Thursday, more showers and storms can be
counted on for late in the week.

&&

.NEAR TERM /THROUGH TODAY/...
Frontal boundary across the Western Southern Tier will push
northward overnight with some renegade showers. A sultry night south
of the warm front with low temps a few degrees within 70F. Could be
some fog given abundant moisture in low-levels.

Expect convection to follow a more typical evolution on Tuesday as
we will be within the warm sector. Thunderstorms could form as early
as midday closer to lake breeze boundaries but will then expand
through afternoon during peak heating. MLCAPES solidly 1000-1500j/kg
and stronger shear than today point to better setup in terms of
severe weather, but with very high freezing levels and steep low-
level lapse rates, main hazards will continue to be heavy tropical
downpours and strong to damaging wind gusts. Our area remains
highlighted by SPC for marginal risk of severe and by WPC for
marginal to slight risk of excessive rainfall.

On Tuesday night, approaching shortwave trough and pre-frontal sfc
trough work across area. Initial convection from afternoon activity
will shift east of the area before additional showers and some
thunderstorms move back over western NY overnight ahead of the
approaching upper level trough. Main potential for heavy rain and
gusty winds will be in the evening. Still a warm and humid night
ahead of cold front out to the west of our region.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
The longwave trough axis and associated weak cold front over the
Eastern Great Lakes will push through the region on Wednesday,
bringing another round of showers and thunderstorms to the area.
Continued moisture advection on a southwesterly flow will keep PWATs
elevated on the order of 1.5-2", as diurnal instability builds CAPE
values to around 800J/kg. With these ingredients in place, there
will be a risk for flash flooding, though likely not as high of a
threat than on Tuesday. Model guidance has come into better
agreement with the axis of heaviest precipitation progressing
through the area a bit quicker, which should help limit flash flood
potential.

Much drier air quickly builds in behind the front, bringing an end
to the rain showers from west to east after sundown Wednesday
evening. Dry conditions should last through the night as surface
ridging builds over the area. Lows Wednesday night will be in the
low to mid 60s areawide.

A warm front moving through the region Thursday with a moistening
airmass brings rain chances back to the area, though 850mb warm air
advection will greatly limit overall instability. The majority of
the area should remain mostly dry throughout the day, though a few
diurnally driven showers and thunderstorms will not be out of the
question. Thursday night should remain dry behind the front, though
it will be notably more muggy with downsloping winds bringing
overnight low temperatures into the low 70s across the lower
terrain, mid 60s elsewhere.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The long term period will be showery as a trough slowly crosses the
Great Lakes through the weekend. Ahead of this trough, a cold front
will cross the area on Friday. Behind the frontal passage, with the
trough still over the region, diurnal showers and storms will be
possible each day, with weakening and tapering off during the night
time hours. A few shortwave troughs within the larger scale trough
will also continue to support the showery pattern.

Temperatures on Friday will be in the low to mid 80s for most of the
area, with a few upper 80s possible in the warmer spots of the
Genesee Valley and Northern Finger Lakes. Behind the passing cold
front, daytime temperatures will cool some to the mid 70s and low
80s through Monday. Temperatures each night will generally be in the
upper 50s to mid 60s from the higher terrain to the lower
elevations, respectively.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Vast majority of the region will experience VFR conditions for the
remainder of the overnight...although IFR to LIFR cigs will be found
across many of the airfields in the Southern Tier where moderately
heavy showers fell during the evening (ie KJHW, KOLE and KELZ).

The low stratus and fog across the Southern Tier will lift to VFR
conditions by mid morning...otherwise mainly VFR conditions are
anticipated for Tuesday. The problem on Tuesday though will be
somewhat stronger convection that is forecast to break out during
the afternoon. This will especially be the case from the Southern
Tier and Finger Lakes into the Eastern Lake Ontario region. These
storms will have the potential to become strong to severe.

Any convection Tuesday evening will die off during the overnight.
Most of the TAF sites will experience VFR weather, while stratus and
fog will encourage IFR conditions across the Southern Tier.

Outlook...

Tuesday night through Wednesday...Generally VFR, with periods of
MVFR/IFR early Tuesday evening and again Wednesday afternoon in
showers and thunderstorms.
Thursday through Saturday...Mainly VFR. A chance of showers and
thunderstorms in the afternoon.

&&

.MARINE...
Generally modest flow averaging 10 to 15 knots will remain in
place through Tuesday. Northeast winds will veer to the south
(Lk Ont) and southwest (Lk Erie). This will allow for smoother
conditions on Lake Ontario with some chop anticipated on Lake
Erie by Tuesday afternoon.

There will be the risk for thunderstorms throughout the Lower Great
lakes...mainly through early evening on Lake Erie south of Dunkirk
and more so Tuesday afternoon into Tuesday evening all areas.
Mariners should be alert for possible statements and special marine
warnings in the presence of these storms.

&&

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

&&

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

Hazardous Weather Outlook
National Weather Service Buffalo NY
915 PM EDT Mon Jul 12 2021

NYZ001>008-010>014-019>021-085-140115-
Niagara-Orleans-Monroe-Wayne-Northern Cayuga-Oswego-Jefferson-Lewis-
Northern Erie-Genesee-Wyoming-Livingston-Ontario-Chautauqua-
Cattaraugus-Allegany-Southern Erie-
915 PM EDT Mon Jul 12 2021

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

.DAY ONE...Tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

There will be a continued risk for heavy rain and localized gusty
winds with thunderstorms on Tuesday and Wednesday.

.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-SLZ022-024-140115-
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-
915 PM EDT Mon Jul 12 2021

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

.DAY ONE...Tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

There will be a continued risk for localized gusty winds with
thunderstorms on Tuesday and Wednesday.

.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

Apffel

Special Weather Statement
National Weather Service Buffalo NY
340 AM EDT Tue Jul 13 2021

NYZ008-130830-
Lewis-
340 AM EDT Tue Jul 13 2021

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT LEWIS COUNTY...

At 338 AM EDT, strong thunderstorms were clustered across southern
Lewis county, moving northeast at 40 mph.

Winds in excess of 30 mph are possible with these storms.

Locations impacted include...
Lowville, Whetstone Gulf State Park, Highmarket, New Bremen, Watson,
Martinsburg, Lyonsdale, Greig, Port Leyden, Croghan, Lyons Falls,
Constableville, Turin, Belfort, Soft Maple Reservoir, Kirschnerville,
Rector, Mohawk Hill, North Osceola and Talcottville.

Torrential rainfall is occurring with this storm, and may cause
localized flooding. Radar has estimated that the storms have a
history of producing up to an inch of rain in 45 minutes time. Do
not drive your vehicle through flooded roadways.

LAT...LON 4347 7543 4353 7570 4372 7577 4410 7517
      4361 7511
TIME...MOT...LOC 0738Z 236DEG 47KT 4372 7531

RSH