Special Weather Statement, NWS Buffalo, NY

Area Forecast Discussion
National Weather Service Buffalo NY
144 PM EDT Fri Sep 6 2024

.SYNOPSIS...
A strong cold front will move slowly across the area, with periods
of rain and a few thunderstorms this afternoon through tonight
across Western NY, and late tonight through a portion of Saturday
for areas east of Lake Ontario. A much cooler airmass will pour into
the eastern Great Lakes behind the cold front, with chilly
temperatures and some lake effect rain east of Lake Erie and Lake
Ontario at times later Saturday through Monday. The cool down will
not last long, with summer-like temperatures and an extended period
of dry weather starting Tuesday.

&&

.NEAR TERM /THROUGH SATURDAY/...
A sharp mid level trough will dig from the upper Great Lakes this
afternoon to the eastern Great Lakes and western Quebec by Saturday
evening, with the trough axis taking on a negative tilt with time. A
mid level closed low will evolve in the base of the trough near
Georgian Bay tonight, then move to the southwest corner of Quebec by
Saturday evening while strengthening with time. This dynamic system
will bring a significant change to our recent dry and warm weather,
with widespread rain followed by much cooler temperatures and lake
effect rain over the weekend.

Radar imagery showing the first batch of showers and a few embedded
thunderstorms over Lake Erie starting to move onshore across far
Western NY. Some very limited instability over Western NY will
continue to support scattered to numerous showers and a few embedded
thunderstorms advancing slowly east across Western NY through the
rest of the afternoon. Expect the leading edge of showers to reach
the Genesee Valley by late afternoon. Meanwhile east of Lake
Ontario, sunshine will continue through mid afternoon before
mid/high clouds increase late in the day.

Tonight through the first half of Saturday the slow moving cold
front will cross the region from west to east. The front will become
increasingly anabatic in nature as one or two weak baroclinic waves
run northward along the boundary. The wavy nature of the front will
slow its eastward progression to a crawl at times, and also enhance
convergence and frontogenesis along the boundary in response to low
level flow adjustments associated with the baroclinic wave. The
increase in moisture and forcing along the front should result in a
fairly widespread area of rain (both ahead and behind the surface
front) developing this evening across Western NY, then progressing
slowly east from there. The best chance of thunder will be across
Western NY this afternoon and early evening when some limited
diurnal instability will be available. Thunder chances will then
decrease with time and eastern extent tonight through Saturday,
although there may still be a minor amount of embedded thunder.

As far as timing goes, the most widespread rain in Western NY will
be from mid to late afternoon through the first half of tonight,
this evening through early Saturday morning for the Genesee Valley
and western Finger Lakes, and late tonight through early afternoon
Saturday east of Lake Ontario. Rainfall amounts will average 0.50"
to 1.0" in most areas, but a few locations may exceed 1.0" where the
baroclinic wave stalls the boundary.

Much cooler air aloft will pour into the eastern Great Lakes in the
wake of the departing cold front late tonight and Saturday. A brief
mid level dry slot and subsidence behind the cold front will give
way to increasing wrap around moisture and growing convective cloud
depths over the lakes in the afternoon as the cold air deepens. This
will allow for increasing lake response on WNW flow. Off Lake Erie,
expect lake effect showers to increase across the Western Southern
Tier during the afternoon. Off Lake Ontario, lake effect showers
will increase along, or just offshore of the south shore of the lake
in the afternoon, reaching Oswego County by late afternoon or early
evening. Outside of these areas, a few scattered showers will
develop Saturday afternoon in response to wrap around moisture and
steepening lapse rates. There may also be a few meandering bands of
lake effect showers from Lake Huron.

The other big story will be the much cooler temperatures. Highs may
briefly touch 60 east of Lake Ontario and on the lake plains of
Western NY, but otherwise ongoing cold advection will keep
temperatures in the 50s for most of the day.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
A much colder airmass will pour into the eastern Great Lakes
Saturday behind a strong cold front. Guidance continues to advertise
850MB temps plunging to 0C to +1C across the lakes by Saturday
evening. Given the strong over lake instability some measure of a
lake response will 'likely' take place. That said...the limiting
factor holding back any kind of real organized significant lake
effect rains will be the available synoptic moisture. With this
update...it appears the best shot will be Saturday night off Lake
Ontario. This will occur as a bit deeper moisture wraps in across
the lake when the mid-level low begins to pass to our north. Off
Lake Erie...given the W-WNW flow significant organized lake effect
rain is unlikely at this point, but there will still be some showers
east of the lake overnight.

The mid-level low will quickly pull away from the region Sunday. We
should see lake induced showers begin to tapper off east of Lake
Erie as drier air works in, and also as mid-levels begin to warm.
Off Ontario...it may take a bit longer for the lake effect showers
to taper off given the longer fetch of the lake. Additionally...there
is some indication of a weak shortwave dropping down the backside
of the trough Sunday night into Monday. This may introduce some
more shower activity, or even keep lake effect going off lake
Ontario through much of Monday. Given the uncertainty after Sunday,
have elected to hold off on increasing PoPs but its worth noting
that Monday may not be completely dry. Stay tuned.

Otherwise...a cool fall-like day will be in-store Sunday with highs
peaking in the upper 50s to low/mid 60s. we should see a nice
rebound in temps Monday, with highs peaking in the upper 60s to
low/mid 70s.

Monday night...surface high pressure will begin to take over bringing
what looks like an extended period of dry quite weather and a
warming trend. Back to summer-like warmth by the middle of next week.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
High pressure will bring an extended period of dry weather and a
continual day to day warming trend through Thursday. Temperatures
will average +10F to +15F above normal with highs peaking in the
upper 70s to low/mid 80s by Wednesday and again on Thursday.

Looking further out to NEXT weekend into the following (third) week...
there is fairly strong consensus between various model platforms that
an Icelandic sfc low will be ever present over the North Atlanic with a
general lack of any notable mid level ridging over Greenland and
adjacent areas. Meanwhile...the arctic jet will remain parked north of
50N while late season ridging will be locked over the southeast U.S.
This negative NAO pattern...contrary to the ensemble used by CPC...
will strongly support ABOVE normal temps during this time frame. Stormy
weather looks unlikely given the lack of amplitude of the jet over the
Lower 48.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
A strong, slow moving cold front will bring periods of rain and a
few embedded thunderstorms to Western NY this afternoon through
tonight, the Genesee Valley this evening through early Saturday
morning, and east of Lake Ontario late tonight through a portion of
Saturday. The rain will be moderately heavy at times, reducing VSBY
to MVFR or even brief IFR. The best chance of embedded thunder will
be across Western NY this afternoon and evening, with coverage of
thunder then decreasing overnight through Saturday as the front
moves slowly east.

Following the widespread rain along the cold front, lake effect rain
showers will start to develop Saturday across Western NY,
progressing to the southeast end of Lake Ontario by evening. Most of
the lake effect rain will be across the higher terrain east of Lake
Erie, and points southeast of Lake Ontario, although a few showers
from Lake Huron may cross other locations in Western NY.

CIGS will deteriorate to a mix of lower end MVFR and IFR along and
behind the cold front, first this evening across Western NY, and
then overnight farther east. CIGS will gradually improve to a mix of
MVFR and lower end VFR during the day Saturday, with MVFR still
favored through the afternoon across higher terrain and in
developing bands of lake effect rain showers.

Outlook...

Sunday and Monday...VFR/MVFR with a chance of lake effect rain
showers at times east of Lake Erie and Lake Ontario.
Tuesday through Wednesday...Mainly VFR.

&&

.MARINE...
A strong cold front will slowly cross the lower Great Lakes tonight
through early Saturday with periods of rain and a few embedded
thunderstorms. Behind the front, much cooler air will pour into the
region Saturday, with a moderate pressure gradient and very unstable
boundary layer thermal profiles supporting an extended period of
blustery conditions on the lakes.

Small Craft Advisory conditions will start on Lake Ontario by early
Saturday morning, and on Lake Erie later Saturday afternoon. Winds
and waves will then continue to be elevated all the way through
Monday, with the stronger winds and higher waves on Lake Ontario.
Sustained winds will occasionally reach or exceed 25 knots on Lake
Ontario over the weekend. Winds and waves will finally start to
subside Monday night and Tuesday as the pressure gradient relaxes.

The risk of waterspouts will increase Saturday as cooler air aloft
arrives, and continue through Monday. Waterspouts are most likely in
and near bands of convective lake effect clouds and showers where
low level convergence/vorticity is found.

&&

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

&&

SYNOPSIS...Hitchcock
NEAR TERM...Hitchcock
SHORT TERM...AR
LONG TERM...AR/RSH
AVIATION...Hitchcock
MARINE...Hitchcock

Hazardous Weather Outlook
National Weather Service Buffalo NY
542 AM EDT Fri Sep 6 2024

NYZ001>008-010>014-019>021-085-061045-
Niagara-Orleans-Monroe-Wayne-Northern Cayuga-Oswego-Jefferson-Lewis-
Northern Erie-Genesee-Wyoming-Livingston-Ontario-Chautauqua-
Cattaraugus-Allegany-Southern Erie-
542 AM EDT Fri Sep 6 2024

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

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

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

LEZ020-040-041-LOZ030-042>045-062>065-SLZ022-024-061045-
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-
542 AM EDT Fri Sep 6 2024

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

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

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
247 PM EDT Fri Sep 6 2024

NYZ012-020-021-085-061930-
Cattaraugus NY-Allegany NY-Southern Erie NY-Wyoming NY-
247 PM EDT Fri Sep 6 2024

...STRONG THUNDERSTORMS WILL IMPACT WESTERN WYOMING...CATTARAUGUS...
SOUTHEASTERN ERIE AND NORTHWESTERN ALLEGANY COUNTIES THROUGH 330 PM
EDT...

At 247 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from Springville to near Allegany State Park.
Movement was northeast at 40 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

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

Locations impacted include...
Olean, Salamanca, Allegany State Park, Boston, Springville, Colden,
Gowanda, Ashford, Arcade, Allegany, Franklinville, Rushford, Chaffee,
Wales Center, St. Bonaventure, Ashford Hollow, East Concord,
Varysburg, Weston Mills, and Concord.

This includes Interstate 86 between exits 17 and 27.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4201 7892 4250 7898 4277 7857 4281 7833
      4252 7819 4209 7834
TIME...MOT...LOC 1847Z 245DEG 33KT 4250 7868 4210 7878

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

Hitchcock

Special Weather Statement
National Weather Service Buffalo NY
331 PM EDT Fri Sep 6 2024

NYZ012-013-021-062015-
Allegany NY-Livingston NY-Wyoming NY-
331 PM EDT Fri Sep 6 2024

...STRONG THUNDERSTORMS WILL IMPACT EASTERN WYOMING...LIVINGSTON AND
NORTH CENTRAL ALLEGANY COUNTIES THROUGH 415 PM EDT...

At 330 PM EDT, Doppler radar was tracking a cluster of strong
thunderstorms near Warsaw, or 8 miles west of Letchworth State Park,
moving northeast at 35 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

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

Locations impacted include...
Geneseo, Dansville, Letchworth State Park, Perry, Warsaw, Avon, Mount
Morris, Conesus, Portageville, Houghton, York, Groveland,
Springwater, Nunda, Covington, Pike, Castile, Silver Springs,
Leicester, and Wyoming.

This includes Interstate 390 between exits 5 and 8.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4243 7815 4279 7821 4286 7799 4286 7796
      4288 7796 4298 7778 4260 7757 4258 7766
      4257 7766
TIME...MOT...LOC 1930Z 233DEG 31KT 4269 7814

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

Apffel

Special Weather Statement
National Weather Service Buffalo NY
416 PM EDT Fri Sep 6 2024

NYZ003-013-014-062100-
Ontario NY-Livingston NY-Monroe NY-
416 PM EDT Fri Sep 6 2024

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN LIVINGSTON...
SOUTHEASTERN MONROE AND NORTHWESTERN ONTARIO COUNTIES THROUGH 500 PM
EDT...

At 416 PM EDT, Doppler radar was tracking a strong thunderstorm over
Avon, or 8 miles north of Geneseo, moving northeast at 35 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
East Rochester, Fairport, Brighton, Henrietta, Penfield, Avon,
Victor, Honeoye Falls, Lima, Farmington, Mendon, Rush, West
Bloomfield, Livonia, Pittsford, Lakeville, Fishers, Martin, Industry,
and South Lima.

This includes the following highways...
 Interstate 390 between exits 8 and 12.
 Interstate 90 between exits 44 and 46.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4279 7775 4292 7787 4319 7746 4307 7737
      4304 7737 4303 7734 4298 7730
TIME...MOT...LOC 2016Z 235DEG 31KT 4291 7775

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

Apffel