Alert archive / New York / Lake Effect Snow Warnings in 2020

Lake Effect Snow Warning 4, NWS Buffalo, NY

February 26, 20208 counties in New York

NWS Buffalo, NY issued this lake effect snow warning at Feb 26, 2020, 4:27 AM EST for 8 counties in New York. It took effect at Feb 26, 2020, 10:00 PM EST. It was in force for . No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Feb 26, 2020, 4:27 AM EST (09:27 UTC)
In effect from
Feb 26, 2020, 10:00 PM EST
Expired
Feb 26, 2020, 12:58 PM EST
In force
Issued by
NWS Buffalo, NY

Counties Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Jefferson County, NY, Lewis County, NY, Oswego County, NY, Wyoming County, NY

The radar

The Buffalo radar (KBUF), 92 km from the middle of the area, began a volume at 09:26 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 00:00Z, 9.5 hours before the alert went out and 89 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Buffalo Intl Airport, NY at 00:00Z on 2020-02-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Buffalo Intl Airport, NY at 00:00Z on 2020-02-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
510 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
104 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

613 
WWUS41 KBUF 260927
WSWBUF

URGENT - WINTER WEATHER MESSAGE
National Weather Service Buffalo NY
427 AM EST Wed Feb 26 2020

NYZ001-002-010-011-261730-
/O.UPG.KBUF.WS.A.0006.200227T0000Z-200227T1800Z/
/O.NEW.KBUF.WS.W.0003.200227T0300Z-200227T1800Z/
Niagara-Orleans-Northern Erie-Genesee-
Including the cities of Niagara Falls, Medina, Buffalo, 
and Batavia
427 AM EST Wed Feb 26 2020

...WINTER STORM WARNING IN EFFECT FROM 10 PM THIS EVENING TO 1 PM 
EST THURSDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 5 to 9 
  inches. Winds could gust as high as 45 to 50 mph resulting in 
  significant blowing and drifting snow.

* WHERE...Niagara, Orleans, Northern Erie, and Genesee counties.

* WHEN...From 10 PM this evening to 1 PM EST Thursday.

* IMPACTS...Travel will become very difficult with very poor 
  visibility and snow covered roadways. The hazardous conditions 
  will greatly impact the Thursday morning commute. Gusty winds 
  could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Widespread accumulating snow will create dangerous travel conditions.

Submit snow reports through our website or social media.

&&


$$

NYZ012-019-020-085-261730-
/O.UPG.KBUF.WS.A.0006.200227T0000Z-200229T2300Z/
/O.NEW.KBUF.LE.W.0004.200227T0300Z-200229T2300Z/
Wyoming-Chautauqua-Cattaraugus-Southern Erie-
Including the cities of Warsaw, Jamestown, Olean, Orchard Park, 
and Springville
427 AM EST Wed Feb 26 2020

...LAKE EFFECT SNOW WARNING IN EFFECT FROM 10 PM THIS EVENING TO 6 
PM EST SATURDAY...

* WHAT...Long duration heavy lake effect snow expected. Total snow 
  accumulations of 1 to 2 feet with locally higher amounts possible 
  in the most persistent bands. Snowfall rates may reach 1 to 2 
  inches per hour at times. Winds could gust as high as 45 to 50 mph 
  resulting in SIGNIFICANT blowing and drifting snow.

* WHERE...Wyoming, Chautauqua, Cattaraugus, and Southern Erie 
  counties.

* WHEN...From 10 PM this evening to 6 PM EST Saturday.

* IMPACTS...Travel will become be very difficult to impossible with 
  very poor visibility and deep snow cover on roads. The hazardous 
  conditions will greatly impact the morning and evening commutes. 
  Gusty winds could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy snow will fall in relatively narrow bands. If traveling, be 
prepared for rapidly changing road conditions and visibilities.

Submit snow reports through our website or social media.

&&

Experimental content below...do not use operationally
Please see below links for more information on this experiment
http://www.weather.gov/buf/polygon_pdd
http://www.nws.noaa.gov/os/notification/
pns15lake_effect_snowaaa.htm
To view the experimental polygons please see:
http://www.weather.gov/buf/lespolygon
COORD...4246 7812 4280 7798 4288 7820 4278 7848 
        4279 7884 4261 7902 4227 7975 4199 7977 4199 7923 
        4212 7877 
TIME Y20M02D27T1200Z-Y20M02D28T0000Z
COORD...4276 7804 4279 7839 4241 7934 4219 7977 
        4199 7977 4208 7875 4219 7852 4219 7829 4226 7809 
        4233 7817 
TIME Y20M02D28T0000Z-Y20M02D28T1200Z
COORD...4287 7802 4286 7847 4278 7881 4262 7893 
        4233 7939 4221 7973 4199 7977 4213 7933 4216 7873 
        4227 7820 
TIME Y20M02D28T1200Z-Y20M02D29T0000Z
COORD...4248 7809 4286 7797 4286 7847 4278 7878 
        4244 7937 4227 7975 4199 7977 4199 7923 4215 7856 
        4229 7845 
TIME Y20M02D29T0000Z-Y20M02D29T1200Z
COORD...4255 7834 4277 7819 4271 7850 4268 7889 
        4234 7948 4223 7976 4199 7977 4199 7923 4210 7895 
        4222 7843 
TIME Y20M02D29T1200Z-Y20M03D01T0000Z

$$

NYZ006>008-261730-
/O.UPG.KBUF.WS.A.0006.200227T0900Z-200229T2300Z/
/O.NEW.KBUF.LE.W.0004.200227T1200Z-200229T2300Z/
Oswego-Jefferson-Lewis-
Including the cities of Oswego, Watertown, and Lowville
427 AM EST Wed Feb 26 2020

...LAKE EFFECT SNOW WARNING IN EFFECT FROM 7 AM THURSDAY TO 6 PM EST 
SATURDAY...

* WHAT...Long duration heavy lake effect snow expected. Total snow
  accumulations of 2 to 3 feet with locally higher amounts 
  possible in the most persistent lake snows. Snowfall rates may 
  exceed 2 inches per hour at times. Winds could gust as high as 
  45 to 50 mph resulting in SIGNIFICANT blowing and drifting snow.

* WHERE...The Eastern Lake Ontario Region.

* WHEN...From 7 AM Thursday to 6 PM EST Saturday.

* IMPACTS...Travel will become be very difficult to impossible with 
  very poor visibility and deep snow cover on roads. The hazardous 
  conditions will greatly impact the morning and the evening 
  commutes. Gusty winds could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy snow will fall in relatively narrow bands. If traveling, be 
prepared for rapidly changing road conditions and visibilities.

Submit snow reports through our website or social media.

&&

Experimental content below...do not use operationally
Please see below links for more information on this experiment
http://www.weather.gov/buf/polygon_pdd
http://www.nws.noaa.gov/os/notification/
pns15lake_effect_snowaaa.htm
To view the experimental polygons please see:
http://www.weather.gov/buf/lespolygon
COORD...4398 7578 4398 7581 4396 7587 4394 7588 
        4394 7584 4395 7578 
TIME Y20M02D27T1200Z-Y20M02D27T1800Z
COORD...4406 7516 4400 7541 4395 7593 4384 7611 
        4369 7614 4352 7602 4350 7578 4342 7550 4352 7536 
        4360 7513 
TIME Y20M02D27T1200Z-Y20M02D27T1800Z
COORD...4406 7516 4400 7534 4398 7578 4380 7620 
        4364 7614 4356 7622 4349 7569 4342 7550 4352 7536 
        4360 7513 
TIME Y20M02D27T1800Z-Y20M02D28T0000Z
COORD...4380 7515 4384 7514 4385 7517 4383 7517 
        4378 7518 4376 7516 4378 7515 4376 7513 4378 7512 
        4380 7512 
TIME Y20M02D28T0000Z-Y20M02D28T0600Z
COORD...4402 7519 4390 7548 4389 7577 4374 7622 
        4359 7622 4345 7656 4342 7631 4348 7581 4342 7550 
        4360 7513 
TIME Y20M02D28T0000Z-Y20M02D28T0600Z
COORD...4387 7514 4387 7522 4377 7606 4356 7622 
        4352 7644 4336 7662 4338 7593 4347 7570 4342 7550 
        4360 7513 
TIME Y20M02D28T0600Z-Y20M02D28T1200Z
COORD...4345 7555 4347 7570 4345 7570 4343 7556 
TIME Y20M02D28T1200Z-Y20M02D29T0000Z
COORD...4389 7513 4385 7559 4389 7577 4379 7606 
        4354 7617 4336 7638 4330 7600 4348 7581 4329 7584 
        4360 7513 
TIME Y20M02D28T1200Z-Y20M02D29T0000Z
COORD...4345 7555 4347 7570 4345 7570 4343 7556 
TIME Y20M02D29T0000Z-Y20M02D29T0600Z
COORD...4360 7513 4389 7513 4389 7577 4375 7609 
        4356 7622 4343 7661 4325 7661 4319 7595 4348 7581 
        4342 7550 
TIME Y20M02D29T0000Z-Y20M02D29T0600Z
COORD...4360 7513 4384 7514 4385 7580 4351 7629 
        4343 7661 4325 7661 4328 7620 4319 7598 4348 7581 
        4342 7550 
TIME Y20M02D29T0600Z-Y20M03D01T0000Z

$$

NYZ021-261730-
/O.NEW.KBUF.LE.W.0004.200227T0300Z-200229T2300Z/
Allegany-
Including the city of Wellsville
427 AM EST Wed Feb 26 2020

...LAKE EFFECT SNOW WARNING IN EFFECT FROM 10 PM THIS EVENING TO 6 
PM EST SATURDAY...

* WHAT...Prolonged heavy lake effect snow expected. Total snow 
  accumulations of 10 to 20 inches in the most persistent lake 
  snows. Winds could gust as high as 45 to 50 mph resulting in 
  significant blowing and drifting snow.

* WHERE...Northwest Allegany county.

* WHEN...From 10 PM this evening to 6 PM EST Saturday.

* IMPACTS...Travel will become very difficult. Areas of blowing 
  snow could significantly reduce visibility. The hazardous 
  conditions will impact the morning or evening commutes. Gusty 
  winds could bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy snow will fall in relatively narrow bands. If traveling, be 
prepared for rapidly changing road conditions and visibilities.

Submit snow reports through our website or social media.

&&

Experimental content below...do not use operationally
Please see below links for more information on this experiment
http://www.weather.gov/buf/polygon_pdd
http://www.nws.noaa.gov/os/notification/
pns15lake_effect_snowaaa.htm
To view the experimental polygons please see:
http://www.weather.gov/buf/lespolygon
COORD...4246 7812 4280 7798 4288 7820 4278 7848 
        4279 7884 4261 7902 4227 7975 4199 7977 4199 7923 
        4212 7877 
TIME Y20M02D27T1200Z-Y20M02D28T0000Z
COORD...4276 7804 4279 7839 4241 7934 4219 7977 
        4199 7977 4208 7875 4219 7852 4219 7829 4226 7809 
        4233 7817 
TIME Y20M02D28T0000Z-Y20M02D28T1200Z
COORD...4287 7802 4286 7847 4278 7881 4262 7893 
        4233 7939 4221 7973 4199 7977 4213 7933 4216 7873 
        4227 7820 
TIME Y20M02D28T1200Z-Y20M02D29T0000Z
COORD...4248 7809 4286 7797 4286 7847 4278 7878 
        4244 7937 4227 7975 4199 7977 4199 7923 4215 7856 
        4229 7845 
TIME Y20M02D29T0000Z-Y20M02D29T1200Z

$$

NYZ004-005-261730-
/O.NEW.KBUF.WS.A.0007.200228T0300Z-200229T2300Z/
Wayne-Northern Cayuga-
Including the cities of Newark and Fair Haven
427 AM EST Wed Feb 26 2020

...WINTER STORM WATCH IN EFFECT FROM THURSDAY EVENING THROUGH
SATURDAY AFTERNOON...

* WHAT...Heavy lake effect snow possible. Total snow accumulations
  of 7 to 14 inches possible in the most persistent lake snows.
  Winds could gust as high as 45 to 50 mph resulting in
  significant blowing and drifting snow.

* WHERE...Wayne and Northern Cayuga counties.

* WHEN...From Thursday evening through Saturday afternoon.

* IMPACTS...Travel could be very difficult. Areas of blowing snow
  could significantly reduce visibility. The hazardous conditions
  could impact the morning or evening commute. Gusty winds could 
  bring down tree branches.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Narrow bands of heavy snow could impact portions of the region.
Localized travel problems will be possible.

&&

$$

TMA
1 follow-up statement
784 
WWUS41 KBUF 261758
WSWBUF

URGENT - WINTER WEATHER MESSAGE
National Weather Service Buffalo NY
1258 PM EST Wed Feb 26 2020

NYZ012-019>021-085-270200-
/O.UPG.KBUF.LE.W.0004.200227T0300Z-200229T2300Z/
/O.NEW.KBUF.BZ.W.0001.200227T0300Z-200228T2100Z/
Wyoming-Chautauqua-Cattaraugus-Allegany-Southern Erie-
Including the cities of Warsaw, Jamestown, Olean, Wellsville, 
Orchard Park, and Springville
1258 PM EST Wed Feb 26 2020

...BLIZZARD WARNING IN EFFECT FROM 10 PM THIS EVENING TO 4 PM EST
FRIDAY...

* WHAT...Blizzard conditions expected. Total snow accumulations of
  1 to 2 feet. Winds gusting as high as 45 to 55 mph will result
  in severe blowing and drifting snow.

* WHERE...Southern Erie and Wyoming counties and the western 
  Southern Tier.

* WHEN...From 10 PM this evening to 4 PM EST Friday.

* IMPACTS...Travel could be very difficult to impossible. Areas of
  blowing snow will produce near zero visibility. The hazardous
  conditions will impact the morning and evening commutes Thursday
  and Friday. Strong winds could cause some tree damage and
  isolated power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Strong winds will cause significant blowing and drifting snow,
frequently reducing visibilities to zero. Travel is strongly
discouraged.

&&

$$

NYZ006>008-270200-
/O.UPG.KBUF.LE.W.0004.200227T1200Z-200229T2300Z/
/O.NEW.KBUF.BZ.W.0001.200227T1200Z-200228T2100Z/
Oswego-Jefferson-Lewis-
Including the cities of Oswego, Watertown, and Lowville
1258 PM EST Wed Feb 26 2020

...BLIZZARD WARNING IN EFFECT FROM 7 AM THURSDAY TO 4 PM EST
FRIDAY...

* WHAT...Blizzard conditions expected. Total snow accumulations of
  3 to 4 feet across the Tug Hill Plateau, and 1 to 2 feet for
  surrounding lower elevations. Winds gusting as high as 50 to 60
  mph will result in severe blowing and drifting snow.

* WHERE...The Eastern Lake Ontario Region.

* WHEN...From 7 AM Thursday to 4 PM EST Friday.

* IMPACTS...Travel could be very difficult to impossible. Areas of
  blowing snow will produce near zero visibility. The hazardous
  conditions will impact the morning and evening commutes Thursday
  and Friday. Strong winds could cause some tree damage and
  scattered power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Strong winds will cause significant blowing and drifting snow,
frequently reducing visibilities to zero. Travel is strongly
discouraged.

&&

$$

NYZ001-002-010-011-270200-
/O.NEW.KBUF.WW.Y.0015.200227T1800Z-200228T2100Z/
/O.CON.KBUF.WS.W.0003.200227T0300Z-200227T1800Z/
Niagara-Orleans-Northern Erie-Genesee-
Including the cities of Niagara Falls, Medina, Buffalo, 
and Batavia
1258 PM EST Wed Feb 26 2020

...WINTER STORM WARNING REMAINS IN EFFECT FROM 10 PM THIS EVENING
TO 1 PM EST THURSDAY...
...WINTER WEATHER ADVISORY IN EFFECT FROM 1 PM THURSDAY TO 4 PM
EST FRIDAY...

* WHAT...For the Winter Storm Warning, heavy snow expected. Total
  snow accumulations of 4 to 8 inches. For the Winter Weather
  Advisory, snow expected. Total snow accumulations of 1 to 3
  inches. Winds gusting as high as 50 to 55 mph will result in
  blowing and drifting snow with greatly reduced visibility from
  Thursday morning through Friday.

* WHERE...Niagara, Orleans, Northern Erie, and Genesee counties.

* WHEN...For the Winter Storm Warning, from 10 PM this evening 
  to 1 PM EST Thursday. For the Winter Weather Advisory, from 1 
  PM Thursday to 4 PM EST Friday.

* IMPACTS...Travel could be very difficult at times with snow
  covered roads. Areas of blowing snow could significantly reduce
  visibility. The hazardous conditions will impact the morning and
  evening commutes Thursday and Friday. Strong winds could cause
  some tree damage and result in isolated power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Widespread accumulating snow will create dangerous travel
conditions.

Submit snow reports through our website or social media.

Periods of snow will result in snow covered roads and limited
visibilities. Slow down and use caution while driving.

Submit snow reports through our website or social media.

&&

$$

NYZ004-005-270200-
/O.NEW.KBUF.WW.Y.0015.200227T0900Z-200228T2100Z/
/O.EXT.KBUF.WS.A.0007.200228T2100Z-200229T2300Z/
Wayne-Northern Cayuga-
Including the cities of Newark and Fair Haven
1258 PM EST Wed Feb 26 2020

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM THURSDAY TO 4 PM
EST FRIDAY...
...WINTER STORM WATCH NOW IN EFFECT FROM FRIDAY AFTERNOON THROUGH
SATURDAY AFTERNOON...

* WHAT...For the Winter Weather Advisory, snow expected. Total
  snow accumulations of 2 to 4 inches. Winds gusting as high as 50
  to 55 mph will produce blowing and drifting snow. For the 
  Winter Storm Watch, heavy lake effect snow possible. Total snow 
  accumulations of 5 to 10 inches possible in the most persistent 
  lake snows. Winds could gust as high as 35 mph.

* WHERE...Wayne and Northern Cayuga counties.

* WHEN...For the Winter Weather Advisory, from 4 AM Thursday to 
  4 PM EST Friday. For the Winter Storm Watch, from Friday 
  afternoon through Saturday afternoon.

* IMPACTS...Travel could be very difficult with snow covered
  roads. Areas of blowing snow could significantly reduce
  visibility. The hazardous conditions will impact the morning and
  evening commutes Thursday and Friday. Strong winds could cause
  some tree damage and result in isolated power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Periods of snow will result in snow covered roads and limited
visibilities. Slow down and use caution while driving.

Submit snow reports through our website or social media.

Narrow bands of heavy snow could impact portions of the region.
Localized travel problems will be possible.

&&

$$

NYZ003-013-014-270200-
/O.NEW.KBUF.WW.Y.0015.200227T0900Z-200228T2100Z/
Monroe-Livingston-Ontario-
Including the cities of Rochester, Geneseo, and Canandaigua
1258 PM EST Wed Feb 26 2020

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM THURSDAY TO 4 PM
EST FRIDAY...

* WHAT...Snow and blowing snow expected. Total snow accumulations
  of 2 to 4 inches. Winds gusting as high as 50 to 55 mph will
  produce blowing and drifting snow.

* WHERE...Monroe, Livingston, and Ontario counties.

* WHEN...From 4 AM Thursday to 4 PM EST Friday.

* IMPACTS...Plan on snow covered and slippery road conditions.
  Areas of blowing snow could significantly reduce visibility. The
  hazardous conditions could impact the morning or evening
  commute. Strong winds could cause some tree damage and result in
  isolated power outages.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Periods of snow will result in snow covered roads and limited
visibilities. Slow down and use caution while driving.

Submit snow reports through our website or social media.

&&

$$

Hitchcock

What forecasters said that day

The local office's own words before this lake effect snow warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Buffalo, NY wrote its last area forecast discussion before this lake effect snow warning went out at Feb 25, 10:52 PM EST, 5 hours 35 minutes earlier.

Area forecast discussion, Feb 25, 10:52 PM EST, 5 hours 35 minutes before
Area Forecast Discussion
National Weather Service Buffalo NY
1052 PM EST Tue Feb 25 2020

.SYNOPSIS...
Rather active weather will prevail through the rest of this week.
Initially low pressure over the Ohio Valley will bring another round
of mixed rain and wet snow to the region tonight...with this then
changing to rain and temporarily breaking off for a time during
Wednesday. The low will then rapidly strengthen and track across our
area later Wednesday and Wednesday night while bringing a round of
moderate to heavy rain that will eventually change over to snow...
which will likely produce at least some moderate general snowfall
accumulations across far western New York from later Wednesday night
into Thursday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Tonight and Wednesday morning the west-to-east oriented baroclinic
zone across our region will tighten a little more while slowly
pivoting northwestward in response to digging upper-level troughing
across the Mississippi Valley and Upper Great Lakes. As this
occurs...another shot of weak to modest isentropic upglide across
the baroclinic zone will generate another band of light precip that
will first pivot northward across our region tonight and thenceforth
into Southern Ontario Wednesday morning...for which categorical PoPs
remain in play. With respect to ptype...mainly rain at the onset
this evening will once again tend to go over to a mix of rain and
wet snow as the lower levels of the atmosphere cool...with snow
generally becoming more predominant overnight. Wednesday morning the
precip will then tend to temporarily taper off from southeast to
northwest while also changing back over mainly rain as the low
levels warm again. As for potential snow amounts...the light nature
of the precip and the very marginal temperature profiles will help
to keep these on the light side...with 1 to 3 inches of slushy
accumulation possible across the higher terrain and northern
portions of the Niagara Frontier and North Country...and a general
inch or less expected elsewhere.

Wednesday afternoon and night the digging upper level trough will
make its way eastward across the Lower Great Lakes and Ohio Valley...
while also taking on a considerable negative tilt. Strong height
falls and DCVA on the eastern flank of this very dynamic feature
will help encourage the previously broad and poorly organized
surface low to markedly deepen and lift northward across our area
between late Wednesday and especially Wednesday night...along with
an attendant swath of moderate to heavy precipitation given the
increasingly impressive dynamics and deep moisture.

Initially...thermal profiles across our region will still be warm
enough for predominantly rain as the moderate to heavy precipitation
begins overspreading our region later Wednesday afternoon and early
Wednesday evening. After that time though...colder air wrapping in
behind the backside of this system will then drive a southwest-
northeast changeover to snow during the course of Wednesday night
and very early Thursday morning.

What's concerning about this is that compared to 24 hours ago...the
track of the surface low has trended notably further to the
southeast in almost all of the available guidance...which is a
marked reversal of the further northwestward track seen over the
previous few days. This change has important implications for far
western New York...where thermal profiles now appear to turn colder
faster and allow for a faster changeover from rain to snow Wednesday
night...thereby raising the specter of a period of accumulating
moderate to heavy snow from later Wednesday night into Thursday
morning. While there is still a fair amount of disagreement amongst
the various model packages on potential snowfall amounts stemming
from this...at least some advisory-type accumulations are starting
to appear likely across far western New York...with warning-criteria
snowfall amounts possible given some of the more impressive model
solutions (most notably the ECMWF). With this and the abrupt shift
in the guidance both in mind...we have elected to hoist a new Winter
Storm Watch for the Niagara Frontier for Wednesday night and
Thursday morning...and have also moved up the start time of the
existing Watch for the Southern Tier to cover this potential initial
synoptic snowfall...in addition to the lake enhancement that is
still expected to begin there later Wednesday night.

Meanwhile from about the Genesee Valley eastward...warmer air will
linger in place longer and should help to severely limit the
potential for accumulating snows until very late Wednesday night or
early Thursday morning...with any accumulations through daybreak
Thursday likely to remain on the order of a few tenths of an inch to
2 inches.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
...Significant Snowfall along with High Winds Anticipated for
Parts of the Region...

Low pressure will become increasingly vertically stacked on
Thursday, with the system moving into southern Quebec and then
stalling by late in the day. Strong cold advection in the wake of
the departing low will allow much colder air to pour back into the
region from west to east in the morning, setting the stage for what
will be an extended period of lake effect and lake enhanced
snowfall.

The heavy snow potential from Wednesday night will rapidly exit
Thursday morning. Abundant wrap around moisture will produce
areas of light snow Thursday across much of the region,
especially Western NY and the eastern Lake Ontario region, with
a relative minima in snow by afternoon for the Genesee Valley
and western Finger Lakes. Lake enhanced snow will be embedded
within the general area of synoptic snow as cold air rapidly
deepens and lake induced equilibrium levels rise to near 10K feet.

Off Lake Erie, lake enhanced and orographically enhanced snow will
focus on the higher terrain of the Chautauqua Ridge, Boston Hills,
and western Wyoming County. The deepest moisture and best synoptic
scale support will be in the morning, and this should support a
steady moderate, to marginally heavy snow in the upslope areas east
of Lake Erie. The deeper moisture and better synoptic ascent will
move away by afternoon, resulting in a lowering of snowfall rates
across upslope areas.

Off Lake Ontario, westerly flow will become established by late
morning or midday, with a strong band of lake effect/lake enhanced
snow targeting the Tug Hill region by afternoon. This will be
embedded within a broader area of light synoptic snow. The snowfall
rates will continue to get heavier as the afternoon progresses and
cold air deepens, and boundary layer flow becomes better aligned.

Thursday night through Saturday the vertically stacked low will
cutoff from the westerlies and drift slowly east across southern
Quebec. Model guidance has remained fairly consistent with this idea
since yesterday, although the latest models have a little more in
the way of widespread light synoptic snow through the period. The
synoptically forced snow will increase Friday afternoon and continue
Friday night through Saturday morning as the western tail of the mid
level trough moves southeast across the eastern Great Lakes, and the
deepest synoptic scale moisture crosses the area. This will produce
light to borderline moderate snow accumulations across much of the
region, with a relative minima across the valleys of Livingston and
Allegany counties where downsloping will minimize snowfall.

The synoptic scale pattern continues to support the idea of a
significant and long lasting lake effect/lake enhanced snow event.
CIPS analogs continue to return impressive analog means in terms of
snowfall, and also return some notable dates of analog events. The
large scale pattern also fits the climatology from our local analog
research for MAJOR lake effect events for east of Lakes Erie
and Ontario.

Off Lake Erie...

Persistent westerly flow will support lake enhanced upslope snow
across the higher terrain east of the lake Thursday night through
Saturday, with boundary layer flow slowly veering more northwesterly
late Friday night and Saturday. The highest snowfall rates will
likely occur Friday afternoon and Friday night when deeper synoptic
scale moisture and support move back over Western NY. The lake
enhanced snow will then decrease quickly in areal coverage and
intensity through the day Saturday as deeper moisture pulls away,
and inversion heights begin to lower.

As far as snowfall amounts go, storm totals are likely to reach 1-2
feet across the higher terrain inland from Lake Erie along the
Chautauqua Ridge, Boston Hills, and western Wyoming County. Some
localized amounts of over 2 feet are possible. Note, this does not
include the synoptic snow that precedes the main lake effect event.

Off Lake Ontario...

The heaviest snow will likely occur Thursday night with well aligned
westerly flow down the long axis of the lake, interacting
cooperatively with orographic enhancement on the Tug Hill Plateau.
Snowfall rates may reach 2+ inches per hour and this one 12 hour
period could produce well over a foot of accumulation for the Tug
Hill. On Friday boundary layer flow will begin to veer slightly, and
the position of the upstream mid level trough may also force lake
effect snow to move a little farther south, and re-orient itself
with less potential for one single, strong band, and more potential
for a broad area of lake enhanced snow east and southeast of the
lake. Boundary layer flow will continue to slowly veer more
northwest Friday night and Saturday, spreading lake enhanced snow to
much of the area southeast of the lake. Snowfall rates will decrease
during this time frame, but the footprint of the snow will spread
out over a much wider area. The snow will continue through Saturday
morning before decreasing in areal coverage and intensity Saturday
afternoon and evening as the deeper moisture pulls away.

As far as amounts go, storm totals are likely to reach 2-3 feet on
the Tug Hill with locally higher amounts possible if the band of
heaviest snow stalls in one location long enough. 6-10 inches of
snow is possible for areas southeast of the lake from Orleans to
western Oswego County, including the Rochester area. Much of this
will fall later Friday through Saturday as boundary layer flow veers
more northwesterly. Snowfall rates will not be as high in this phase
of the event. Note, these totals do not include the synoptic snow
that will precede the main lake effect event.

Finally, it will be very windy during the first phase of this lake
effect event Thursday and Thursday night. Wind gusts of 35 to 40 mph
will be common at times, producing significant blowing and drifting
snow. The strongest winds will be on the lake plains where the least
amount of snow will fall. There may be a period with wind gusts up
to or exceeding 45 mph Thursday afternoon and evening. Winds will
become somewhat lighter Friday through Saturday, although there will
still be enough wind to produce at least some limited blowing and
drifting snow in open areas.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The vertically stacked low will continue to slowly fill and
move east into the Canadian Maritimes Saturday night. Synoptic
scale moisture and forcing will diminish from west to east
overnight, with inversion heights lowering steadily. Lake effect
snow showers will continue southeast of the lakes with boundary
layer flow becoming more northwest with time. The best coverage
of snow will be in the evening, with lessening coverage and
intensity through the overnight. Any remaining lake effect snow
showers southeast of the lakes Sunday morning will end as
surface high pressure builds over the eastern Great Lakes,
further lowering inversion heights and drying the column.
Temperatures will remain cold through Sunday under the influence
of the departing deep trough and associated cold air aloft.

Early next week the trough will advance steadily into the North
Atlantic. Rising heights and a westerly flow of Pacific origin air
will build east across the nation Monday and Tuesday. This will
allow temperatures to trend quickly above normal following our 3-4
day period of active winter weather and cold. Monday will be dry as
high pressure drifts off the east coast. Low pressure moving out of
the Ohio Valley will bring an increasing chance of rain showers by
Tuesday.

&&

.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
A moist northeast flow will maintain MVFR cigs across western New
York through about 08z...with a few spots grudgingly holding
onto IFR cigs. As we push into the wee hours of the morning...
deeper moisture associated with a mid level disturbance will
not only contribute to a blossoming area of mixed rain and
snow...but it will encourage MVFR cigs to lower to IFR. Sites
that change to just wet snow will also have vsbys that will drop
to IFR to LIFR levels.

On Wednesday...generally IFR cigs will be in place ahead of an
approaching storm system. Light pcpn associated with the low cloud
cover will become less widespread by midday before additional lift
will lead to increased coverage of rain from west to east late in
the day and in the evening.

The liquid precipitation Wednesday evening will transition to
moderate to occasionally heavy snow over the western TAF sites
during the second half of Wednesday night. This will likely have
significant impacts to ground operations at KBUF and KIAG by
daybreak Thursday.

Outlook...

Thursday and Friday...LIFR/IFR in potentially heavy lake effect snow
east of the lakes...with MVFR/VFR and scattered snow showers
elsewhere. Significant impacts will be possible.
Saturday...IFR/MVFR with lake effect snow southeast of the lakes...
and scattered to numerous snow showers elsewhere.
Sunday...IFR/MVFR in snow showers...becoming VFR.

&&

.MARINE...
Low pressure tracking up the Ohio Valley will bring a period of
brisk northeasterlies to the Lower Great Lakes through tonight and a
good deal of Wednesday...for which Small Craft Advisories are in
effect as outlined below.

Later Wednesday and Wednesday night the surface low will strengthen
markedly and lift northeastward across New York State. Following the
passage of the low...winds will rapidly freshen out of the west
later Wednesday night and Thursday and may lead to a period of gales
on both lakes that would last through Thursday night...for which
Gale Watches are in effect as outlined below.

&&

.TIDES/COASTAL FLOODING...
A period of strong west-southwesterly winds in wake of strong
low pressure could bring a round of lakeshore flooding to Lake
Erie and Lake Ontario late Wednesday night and Thursday.

For Lake Erie, the setup looks increasingly favorable for a seiche
from late Wednesday night through early Thursday afternoon, as
east to southeast winds quickly turn west-southwesterly and increase
to 30 knots or possibly even gale force. The ramp up in winds
may cause the lake level to approach 8 feet above low water datum
at Buffalo with some flooding possible of the Buffalo Harbor,
Canalside, and Dunkirk Harbor.

For Lake Ontario, the combination of high lake levels, strong
onshore westerly winds, and high waves may produce some lakeshore
flooding in bays and inlets at the east end of the lake.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Lakeshore Flood Watch from Thursday afternoon through Friday
     morning for NYZ006-007.
     Winter Storm Watch from late Wednesday night through Saturday
     afternoon for NYZ006>008.
     Winter Storm Watch from Wednesday evening through Thursday
     afternoon for NYZ001-002-010-011.
     Lakeshore Flood Watch from late Wednesday night through
     Thursday afternoon for NYZ010-019-085.
     Winter Storm Watch from Wednesday evening through Saturday
     afternoon for NYZ012-019-020-085.
MARINE...Gale Watch from Thursday morning through Friday morning for
         LEZ040-041.
         Small Craft Advisory until 4 PM EST Wednesday for LEZ040-
         041.
         Gale Watch from Thursday morning through Friday
         morning for LOZ042>045-062>065.
         Small Craft Advisory until 1 AM EST Thursday for LOZ043-
         044.
         Small Craft Advisory until 7 AM EST Thursday for LOZ042.

&&

SYNOPSIS...JJR/RSH
NEAR TERM...JJR
SHORT TERM...Hitchcock
LONG TERM...Hitchcock
AVIATION...RSH
MARINE...JJR
TIDES/COASTAL FLOODING...JJR/TMA
Hazardous weather outlook, Feb 25, 2:50 PM EST, 13 hours 37 minutes before
Hazardous Weather Outlook
National Weather Service Buffalo NY
250 PM EST Tue Feb 25 2020

NYZ001-002-011-262000-
Niagara-Orleans-Genesee-
250 PM EST Tue Feb 25 2020

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH
THURSDAY AFTERNOON...

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

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

   Winter Storm Watch.

.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

NYZ010-262000-
Northern Erie-
250 PM EST Tue Feb 25 2020

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH
THURSDAY AFTERNOON...
...LAKESHORE FLOOD WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY AFTERNOON...

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

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

   Winter Storm Watch.
   Lakeshore Flood Watch.

.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

NYZ019-085-262000-
Chautauqua-Southern Erie-
250 PM EST Tue Feb 25 2020

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH
SATURDAY AFTERNOON...
...LAKESHORE FLOOD WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY AFTERNOON...

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

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

   Winter Storm Watch.
   Lakeshore Flood Watch.

.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

NYZ012-020-262000-
Wyoming-Cattaraugus-
250 PM EST Tue Feb 25 2020

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH
SATURDAY AFTERNOON...

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

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

  Winter Storm Watch.

.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

NYZ003>005-013-014-021-262000-
Monroe-Wayne-Northern Cayuga-Livingston-Ontario-Allegany-
250 PM EST Tue Feb 25 2020

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

A strong low pressure system is expected to move across New York
State Wednesday night, then stall over southern Quebec Thursday
through Saturday. Rain Wednesday and Wednesday evening will change to
wet snow later Wednesday night, with some accumulation possible.

Periods of snow showers will then continue Thursday through
Saturday, with generally light accumulations in most areas. It will
be quite windy Thursday through Thursday night, with wind gusts in
excess of 40 mph possible. This will result in some blowing snow
where enough fresh snow accumulates.

.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

NYZ008-262000-
Lewis-
250 PM EST Tue Feb 25 2020

...WINTER STORM WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
SATURDAY AFTERNOON...

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

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

   Winter Storm Watch.

.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

NYZ006-007-262000-
Oswego-Jefferson-
250 PM EST Tue Feb 25 2020

...WINTER STORM WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
SATURDAY AFTERNOON...
...LAKESHORE FLOOD WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH
FRIDAY MORNING...

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

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

   Winter Storm Watch.
   Lakeshore Flood Watch.

.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-LOZ030-262000-
Upper Niagara River and Buffalo Harbor-Lower Niagara River-
250 PM EST Tue Feb 25 2020

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

A strong area of low pressure will cross New York State Wednesday
night, then move into southern Quebec Thursday and Thursday night.
Westerly gales are possible Thursday and Thursday night.

.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>065-262000-
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-
250 PM EST Tue Feb 25 2020

...GALE WATCH IN EFFECT FROM THURSDAY MORNING THROUGH FRIDAY
MORNING...

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

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

   Gale Watch.

.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

SLZ022-024-262000-
Saint Lawrence River from Cape Vincent to Ogdensburg-
Saint Lawrence River from Ogdensburg to Saint Regis-
250 PM EST Tue Feb 25 2020

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

.DAY ONE...This afternoon and tonight.

The probability of widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

The probability of widespread hazardous weather is low.

.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

JJR

The office that day

Everything else NWS Buffalo, NY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 26, 4:27 AM ESTWinter Storm WatchBUFCayuga, Wayne46 hr
Feb 26, 4:27 AM ESTWinter Storm WarningBUFErie, Genesee, Niagara, Orleans33 hr
Feb 26, 4:32 AM ESTLakeshore Flood WarningBUFChautauqua, Erie, Jefferson, Oswego62 hr
Feb 26, 4:46 AM ESTGale WarningBUF56 hr
Feb 26, 12:58 PM ESTBlizzard WarningBUFAllegany, Cattaraugus, Chautauqua, Erie, Jefferson, Lewis and 2 more48 hr
Feb 26, 12:58 PM ESTWinter Weather AdvisoryBUFCayuga, Erie, Genesee, Livingston, Monroe, Niagara and 3 more32 hr

Nearby

Lake Effect Snow Warnings in New York, 2020Every lake effect snow warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.