Alert archive / New York / Lakeshore Flood Warnings in 2017

Lakeshore Flood Warning 23, NWS Buffalo, NY

December 5, 2017Jefferson County, Oswego County, New York

NWS Buffalo, NY issued this lakeshore flood warning at Dec 5, 2017, 3:49 AM EST for Jefferson County, Oswego County, New York. It took effect at Dec 5, 2017, 11:00 PM EST. It was in force for 14 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Dec 5, 2017, 3:49 AM EST (08:49 UTC)
In effect from
Dec 5, 2017, 11:00 PM EST
Expired
Dec 6, 2017, 12:44 PM EST
In force
14 hr
Issued by
NWS Buffalo, NY

Counties Jefferson County, NY, Oswego County, NY

The radar

The Ft Drum radar (KTYX), 36 km from the middle of the area, began a volume at 08:50 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

Albany, NY (KALY), launched 00:00Z, 8.8 hours before the alert went out and 219 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, Albany, NY at 00:00Z on 2017-12-05Temperature 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, Albany, NY at 00:00Z on 2017-12-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 118 square meters per square second.19395878Sfc1 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
818 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
118 m²/s²
0-3 km storm-relative helicity
182 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

007 
WHUS41 KBUF 050849
CFWBUF

URGENT - IMMEDIATE BROADCAST REQUESTED
LAKESHORE HAZARD MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
349 AM EST TUE DEC 5 2017

NYZ006-007-051700-
/O.NEW.KBUF.LS.W.0023.171206T0400Z-171206T1500Z/
OSWEGO-JEFFERSON-
349 AM EST TUE DEC 5 2017

...LAKESHORE FLOOD WARNING IN EFFECT FROM 11 PM THIS EVENING TO
10 AM EST WEDNESDAY...

THE NATIONAL WEATHER SERVICE IN BUFFALO HAS ISSUED A LAKESHORE
FLOOD WARNING, WHICH IS IN EFFECT FROM 11 PM THIS EVENING TO
10 AM EST WEDNESDAY.

* LOCATIONS...OSWEGO AND JEFFERSON COUNTIES.

* LAKE SHORE FLOODING...A BRIEF PERIOD OF STRONG WEST TO SOUTHWEST
  WINDS LATER TONIGHT THROUGH WEDNESDAY MORNING WILL BRING HIGH
  WAVE ACTION AND AN INCREASE IN SHORELINE EROSION AT THE EAST END
  OF LAKE ONTARIO.

* TIMING...FROM LATE THIS EVENING THROUGH LATE WEDNESDAY MORNING.

* IMPACTS...EXPECT AN INCREASE IN SHORELINE EROSION AT THE EAST
  END OF LAKE ONTARIO. THIS MAY PRODUCE SOME LOCAL PROPERTY DAMAGE
  IN AREAS WHERE THE SHORELINE IS STILL UNSTABLE FOLLOWING THE
  HIGHER WATER FROM EARLIER THIS YEAR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A LAKESHORE FLOOD WARNING MEANS LAKESHORE FLOODING IS OCCURRING,
IS IMMINENT, OR IS EXPECTED TO OCCUR. PEOPLE IN THE WARNING AREA
SHOULD TAKE IMMEDIATE ACTION TO PROTECT LIFE AND PROPERTY. LISTEN
TO LOCAL RADIO...TELEVISION...OR NOAA WEATHER RADIO FOR FURTHER
INFORMATION.

&&

$$

HITCHCOCK/CHURCH
7 follow-up statements
348 
WHUS41 KBUF 051348
CFWBUF

LAKESHORE HAZARD MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
848 AM EST TUE DEC 5 2017

NYZ006-007-052200-
/O.CON.KBUF.LS.W.0023.171206T0400Z-171206T1500Z/
OSWEGO-JEFFERSON-
848 AM EST TUE DEC 5 2017

...LAKESHORE FLOOD WARNING REMAINS IN EFFECT FROM 11 PM THIS
EVENING TO 10 AM EST WEDNESDAY...

* LOCATIONS...OSWEGO AND JEFFERSON COUNTIES.

* LAKE SHORE FLOODING...A BRIEF PERIOD OF STRONG WEST TO 
  SOUTHWEST WINDS LATER TONIGHT THROUGH WEDNESDAY MORNING WILL 
  BRING HIGH WAVE ACTION AND AN INCREASE IN SHORELINE EROSION AT 
  THE EAST END OF LAKE ONTARIO.

* TIMING...FROM LATE THIS EVENING THROUGH LATE WEDNESDAY MORNING.

* IMPACTS...EXPECT AN INCREASE IN SHORELINE EROSION AT THE EAST 
  END OF LAKE ONTARIO. THIS MAY PRODUCE SOME LOCAL PROPERTY 
  DAMAGE IN AREAS WHERE THE SHORELINE IS STILL UNSTABLE 
  FOLLOWING THE HIGHER WATER FROM EARLIER THIS YEAR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A LAKESHORE FLOOD WARNING MEANS LAKESHORE FLOODING IS OCCURRING,
IS IMMINENT, OR IS EXPECTED TO OCCUR. PEOPLE IN THE WARNING AREA
SHOULD TAKE IMMEDIATE ACTION TO PROTECT LIFE AND PROPERTY. LISTEN
TO LOCAL RADIO...TELEVISION...OR NOAA WEATHER RADIO FOR FURTHER
INFORMATION.

&&

$$
099 
WHUS41 KBUF 051938
CFWBUF

LAKESHORE HAZARD MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
238 PM EST TUE DEC 5 2017

NYZ006-007-060400-
/O.CON.KBUF.LS.W.0023.171206T0400Z-171206T1500Z/
OSWEGO-JEFFERSON-
238 PM EST TUE DEC 5 2017

...LAKESHORE FLOOD WARNING REMAINS IN EFFECT FROM 11 PM THIS
EVENING TO 10 AM EST WEDNESDAY...

* LOCATIONS...OSWEGO AND JEFFERSON COUNTIES.

* LAKE SHORE FLOODING...A BRIEF PERIOD OF STRONG WEST TO 
  SOUTHWEST WINDS LATER TONIGHT THROUGH WEDNESDAY MORNING WILL 
  BRING HIGH WAVE ACTION AND AN INCREASE IN SHORELINE EROSION AT 
  THE EAST END OF LAKE ONTARIO.

* TIMING...FROM LATE THIS EVENING THROUGH LATE WEDNESDAY MORNING.

* IMPACTS...EXPECT AN INCREASE IN SHORELINE EROSION AT THE EAST 
  END OF LAKE ONTARIO. THIS MAY PRODUCE SOME LOCAL PROPERTY 
  DAMAGE IN AREAS WHERE THE SHORELINE IS STILL UNSTABLE 
  FOLLOWING THE HIGHER WATER FROM EARLIER THIS YEAR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A LAKESHORE FLOOD WARNING MEANS LAKESHORE FLOODING IS OCCURRING,
IS IMMINENT, OR IS EXPECTED TO OCCUR. PEOPLE IN THE WARNING AREA
SHOULD TAKE IMMEDIATE ACTION TO PROTECT LIFE AND PROPERTY. LISTEN
TO LOCAL RADIO...TELEVISION...OR NOAA WEATHER RADIO FOR FURTHER
INFORMATION.

&&

$$
488 
WHUS41 KBUF 060331
CFWBUF

LAKESHORE HAZARD MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
1031 PM EST TUE DEC 5 2017

NYZ006-007-061215-
/O.CON.KBUF.LS.W.0023.171206T0400Z-171206T1500Z/
OSWEGO-JEFFERSON-
1031 PM EST TUE DEC 5 2017

...LAKESHORE FLOOD WARNING REMAINS IN EFFECT UNTIL 10 AM EST
WEDNESDAY...

* LOCATIONS...OSWEGO AND JEFFERSON COUNTIES.

* LAKE SHORE FLOODING...A BRIEF PERIOD OF STRONG WEST TO 
  SOUTHWEST WINDS LATER TONIGHT THROUGH WEDNESDAY MORNING WILL 
  BRING HIGH WAVE ACTION AND AN INCREASE IN SHORELINE EROSION AT 
  THE EAST END OF LAKE ONTARIO.

* TIMING...FROM LATE THIS EVENING THROUGH LATE WEDNESDAY MORNING.

* IMPACTS...EXPECT AN INCREASE IN SHORELINE EROSION AT THE EAST 
  END OF LAKE ONTARIO. THIS MAY PRODUCE SOME LOCAL PROPERTY 
  DAMAGE IN AREAS WHERE THE SHORELINE IS STILL UNSTABLE 
  FOLLOWING THE HIGHER WATER FROM EARLIER THIS YEAR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A LAKESHORE FLOOD WARNING MEANS LAKESHORE FLOODING IS OCCURRING,
IS IMMINENT, OR IS EXPECTED TO OCCUR. PEOPLE IN THE WARNING AREA
SHOULD TAKE IMMEDIATE ACTION TO PROTECT LIFE AND PROPERTY. LISTEN
TO LOCAL RADIO...TELEVISION...OR NOAA WEATHER RADIO FOR FURTHER
INFORMATION.

&&

$$
667 
WHUS41 KBUF 060602
CFWBUF

LAKESHORE HAZARD MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
102 AM EST WED DEC 6 2017

NYZ006-007-061415-
/O.CON.KBUF.LS.W.0023.000000T0000Z-171206T1500Z/
OSWEGO-JEFFERSON-
102 AM EST WED DEC 6 2017

...LAKESHORE FLOOD WARNING REMAINS IN EFFECT UNTIL 10 AM EST THIS
MORNING...

* LOCATIONS...OSWEGO AND JEFFERSON COUNTIES.

* LAKE SHORE FLOODING...A BRIEF PERIOD OF STRONG WEST TO SOUTHWEST
  WINDS OVERNIGHT THROUGH WEDNESDAY MORNING WILL BRING HIGH WAVE 
  ACTION AND AN INCREASE IN SHORELINE EROSION AT THE EAST END OF 
  LAKE ONTARIO.

* TIMING...THROUGH LATE WEDNESDAY MORNING.

* IMPACTS...EXPECT AN INCREASE IN SHORELINE EROSION AT THE EAST 
  END OF LAKE ONTARIO. THIS MAY PRODUCE SOME LOCAL PROPERTY 
  DAMAGE IN AREAS WHERE THE SHORELINE IS STILL UNSTABLE 
  FOLLOWING THE HIGHER WATER FROM EARLIER THIS YEAR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A LAKESHORE FLOOD WARNING MEANS LAKESHORE FLOODING IS OCCURRING,
IS IMMINENT, OR IS EXPECTED TO OCCUR. PEOPLE IN THE WARNING AREA
SHOULD TAKE IMMEDIATE ACTION TO PROTECT LIFE AND PROPERTY. LISTEN
TO LOCAL RADIO...TELEVISION...OR NOAA WEATHER RADIO FOR FURTHER
INFORMATION.

&&

$$
575 
WHUS41 KBUF 060918
CFWBUF

LAKESHORE HAZARD MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
418 AM EST WED DEC 6 2017

NYZ006-007-061500-
/O.CON.KBUF.LS.W.0023.000000T0000Z-171206T1500Z/
OSWEGO-JEFFERSON-
418 AM EST WED DEC 6 2017

...LAKESHORE FLOOD WARNING REMAINS IN EFFECT UNTIL 10 AM EST THIS
MORNING...

* LOCATIONS...OSWEGO AND JEFFERSON COUNTIES.

* LAKE SHORE FLOODING...A BRIEF PERIOD OF STRONG WEST TO SOUTHWEST
  WINDS THROUGH MID MORNING WILL BRING HIGH WAVE ACTION AND AN 
  INCREASE IN SHORELINE EROSION AT THE EAST END OF LAKE ONTARIO.

* TIMING...THROUGH THE FIRST HALF OF THIS MORNING.

* IMPACTS...EXPECT AN INCREASE IN SHORELINE EROSION AT THE EAST 
  END OF LAKE ONTARIO. THIS MAY PRODUCE SOME LOCAL PROPERTY 
  DAMAGE IN AREAS WHERE THE SHORELINE IS STILL UNSTABLE 
  FOLLOWING THE HIGHER WATER FROM EARLIER THIS YEAR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A LAKESHORE FLOOD WARNING MEANS LAKESHORE FLOODING IS OCCURRING,
IS IMMINENT, OR IS EXPECTED TO OCCUR. PEOPLE IN THE WARNING AREA
SHOULD TAKE IMMEDIATE ACTION TO PROTECT LIFE AND PROPERTY. LISTEN
TO LOCAL RADIO...TELEVISION...OR NOAA WEATHER RADIO FOR FURTHER
INFORMATION.

&&

$$
383 
WHUS41 KBUF 061000
CFWBUF

LAKESHORE HAZARD MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
500 AM EST WED DEC 6 2017

NYZ006-007-061800-
/O.EXT.KBUF.LS.W.0023.000000T0000Z-171206T2300Z/
OSWEGO-JEFFERSON-
500 AM EST WED DEC 6 2017

...LAKESHORE FLOOD WARNING NOW IN EFFECT UNTIL 6 PM EST THIS
EVENING...

* LOCATIONS...OSWEGO AND JEFFERSON COUNTIES.

* LAKE SHORE FLOODING...A PERIOD OF STRONG WEST TO SOUTHWEST WINDS
  THROUGH TODAY WILL BRING HIGH WAVE ACTION AND AN INCREASE IN 
  SHORELINE EROSION AT THE EAST END OF LAKE ONTARIO.

* TIMING...THROUGH TODAY.

* IMPACTS...EXPECT AN INCREASE IN SHORELINE EROSION AT THE EAST 
  END OF LAKE ONTARIO. THIS MAY PRODUCE SOME LOCAL PROPERTY 
  DAMAGE IN AREAS WHERE THE SHORELINE IS STILL UNSTABLE 
  FOLLOWING THE HIGHER WATER FROM EARLIER THIS YEAR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A LAKESHORE FLOOD WARNING MEANS LAKESHORE FLOODING IS OCCURRING,
IS IMMINENT, OR IS EXPECTED TO OCCUR. PEOPLE IN THE WARNING AREA
SHOULD TAKE IMMEDIATE ACTION TO PROTECT LIFE AND PROPERTY. LISTEN
TO LOCAL RADIO...TELEVISION...OR NOAA WEATHER RADIO FOR FURTHER
INFORMATION.

&&

$$
930 
WHUS41 KBUF 061744
CFWBUF

LAKESHORE HAZARD MESSAGE
NATIONAL WEATHER SERVICE BUFFALO NY
1244 PM EST WED DEC 6 2017

NYZ006-007-061845-
/O.CAN.KBUF.LS.W.0023.000000T0000Z-171206T2300Z/
OSWEGO-JEFFERSON-
1244 PM EST WED DEC 6 2017

...LAKESHORE FLOOD WARNING IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN BUFFALO HAS CANCELLED THE
LAKESHORE FLOOD WARNING.

$$

SMITH

What forecasters said that day

The local office's own words before this lakeshore flood 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 lakeshore flood warning went out at Dec 5, 3:49 AM EST, 0 minutes earlier.

Area forecast discussion, Dec 5, 3:49 AM EST, 0 minutes before
Area Forecast Discussion
National Weather Service Buffalo NY
349 AM EST Tue Dec 5 2017

.SYNOPSIS...
A deepening low pressure system tracking from Lake Superior to the
Hudson Bay today will push a strong cold front across the region,
while producing widespread rainfall. As colder air sweeps into the
region tonight, this will set the stage for lake effect snow
northeast and east of Lakes Erie and Ontario through Thursday night
or Friday morning. Outside of the lake effect area, expect only a
few passing snow showers at times.

&&

.NEAR TERM /THROUGH TONIGHT/...
Satellite imagery early this morning shows and impressive, deepening
low pressure system near Lake Superior that is quickly tracking off
to the northeast, and will eventually settle near the Hudson Bay
later today and tonight. A strong low-level jet with impressive
subtropical moisture advection ahead of the attendant cold front can
be demarcated by a broad area of cold cloud tops across the Ohio
Valley and into western NY this morning. Regional radar imagery show
widespread rainfall across WNY and western PA this morning, with
additional precipitation filling in along a pre frontal trough in
Ohio.

As this area of enhanced convergence and moisture advection
ahead of the cold front works its way across the region today,
expect a period of fairly steady rainfall to work its way across WNY
before lunchtime, and through central NY by mid to late afternoon.
Behind this initial widespread rainfall, expect the rain to become
more scattered and showery for this afternoon and evening ahead of
the main cold front, with some enhancement in the upslope areas east
of Lake Erie and Lake Ontario. Rainfall amounts will limited to
around a quarter inch in the Genesee Valley and northern Finger
Lakes from the strong southerly downslope flow. Meanwhile, much of
western NY will see around a third to a half inch, and the North
Country will pick up a half to three quarters. Temperatures today
will be very mild, topping out in the 50s, with even some mid to
upper 50s from the Genesee Valley eastward. Temperatures will cool
quickly this evening and tonight behind the cold front passage.

Behind the cold front passage tonight, low-level lapse rates will
steepen rather quickly in the cold air advection. This will set the
stage for a quick lake response behind the departing cold front and
synoptic precipitation. 850 mb temperatures will fall quickly to
around -8 to -10C by midnight over Lake Erie, with capping
inversions rising to around 8kft. The steering flow behind the front
now looks to be around 250 to begin with, while backing slightly to
around 240 between 09Z and 12Z. Thus expect a band of lake effect
snowfall to develop after midnight near the Buffalo Southtowns out
toward Rochester, while drifting north to near or just south of the
Buffalo Airport out toward Rochester between 09Z and 12Z, while
gaining some intensity. Snowfall rates may quickly climb up to
around an inch per hour, which could produce some trouble for the
Wednesday morning commute in the Buffalo metro area. However,
this burst of heavier snow in the morning may be short-lived,
but more on that in the section below...

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
...Potentially significant lake effect snow event to develop
Wednesday morning and last until Friday morning....

A Winter Storm Watch for Lake Effect Snow remains in effect east and
northeast of Lakes Erie and Ontario, from Wednesday morning through
Friday morning.

00Z model guidance and the overall pattern continue to suggest the
potential for significant lake effect snow east and northeast of
Lakes Erie and Ontario, but there are several important items that
may influence band intensity and location that are still not well
agreed upon in model guidance. The amount of background synoptic
scale moisture is a big concern for Wednesday, and it now appears
likely that moisture will become too shallow for an extended period
of time from mid morning through late afternoon, forcing the bands
of snow to weaken and possibly fall apart altogether. The second
major concern is the boundary layer wind direction Thursday and
Thursday night, with major differences showing up in model guidance.
Given these concerns, we chose to continue with a watch for now.

From a synoptic scale standpoint, the pattern is favorable with a
deep trough centered near James Bay, and cyclonic flow in place
across the Great Lakes. Lake induced instability will be ample with
equilibrium levels rising to around 10K feet late tonight, and
remaining 10-12K feet Wednesday through Friday morning. Several mid
level shortwaves will move across the area, most notably Wednesday
evening. These shortwaves will bring periods of improved moisture
and ascent, and also produce a few scattered snow showers outside of
lake effect areas.

Off Lake Erie...

We expect a brief period of more organized lake effect snow starting
late tonight and continuing through Wednesday morning as the first
push of colder air arrives, with some added synoptic scale moisture
depth and ascent from a subtle mid level shortwave. This first round
of lake effect snow will center from the Buffalo Metro area into
Genesee County. Snowfall rates may briefly exceed 1 inch per hour
and produce a quick 3-5 inches of snow. High resolution model
guidance including the 3KM NAM, HREF 3KM ensemble, and 2.5KM
Canadian GEM nest are in good agreement on developing this band. The
eastern end of this band may also bring some minor accumulations to
Monroe County. This first round may bring difficult travel
conditions for the Wednesday morning commute.

This initial burst of lake effect snow will likely weaken and fall
apart by mid to late morning as the boundary layer becomes too dry
to support a good lake response. This will continue to be the case
through mid to late afternoon, with just a few snow showers across
the Niagara Frontier. Absent of a more significant band,
temperatures will also rise to at least several degrees above
freezing as well.

Another, stronger mid level shortwave will cross the area Wednesday
evening. This feature will bring another period of synoptic scale
ascent, convergence, and deeper moisture. This should allow the band
of snow to rapidly intensify again during the evening, likely over
the Buffalo Northtowns and possibly Niagara/Orleans counties
initially. This band of intensifying snow will then move south
across the Buffalo Metro area and into the Boston Hills and Wyoming
County through the late evening with a burst of heavy snow, and
snowfall rates again exceeding 1 inch per hour. Overnight the band
of lake effect snow will settle farther south into the northern and
western sections of Chautauqua and Cattaraugus counties. This
southward drift is more pronounced during this period than model
guidance 24 hours ago.

Thursday through Thursday night model guidance diverges
significantly on forecast wind direction. The ECMWF and NAM keep the
boundary layer flow westerly, keeping lake effect in the Southern
Tier and far southern Erie/Wyoming counties much of the time. The
GFS and Canadian GEM on the other hand back winds to the WSW and
eventually SW again Thursday afternoon and Thursday night, which
would bring the band of lake effect snow back into the Buffalo and
Batavia areas. The difference in orientation of 850mb heights is
striking at 00Z Friday, and gives below normal confidence on where
the band of lake effect snow will end up being located. Given the
uncertainty in band placement, had to keep a wider than normal area
of POPS east of Lake Erie and spread out the snow accumulations to a
wider area.

Off Lake Ontario...

Expect a similar, brief period of better organized snow Wednesday
morning across central and northern Jefferson County, although
likely not as strong as the Lake Erie response given even more
marginal moisture. This may drop an inch or two of snow in Jefferson
County during the morning. After that, the lack of synoptic scale
moisture and relatively mild surface temperatures will keep
accumulations to a minimum from late morning through late afternoon
Wednesday.

The passage of the mid level trough will rapidly enhance the Lake
Ontario band by mid evening Wednesday across Jefferson County with
an increase in synoptic scale moisture depth, convergence, and
ascent. This band will initially set up in central Jefferson County
near or even just north of Watertown, then push southeast across
Watertown and into the northern portion of the Tug Hill Plateau
overnight. Expect snowfall rates to exceed 1 inch per hour once the
band gets going overnight.

Thursday and Thursday night the placement of the band becomes much
more uncertain given the differences in wind direction explained
above. The ECMWF/NAM guidance keep the flow more westerly,
suggesting the central Tug Hill and even Oswego County would see the
most persistent accumulations. The GFS and Canadian GEM on the other
hand bring the flow more WSW later Thursday, and SW Thursday night,
carrying the lake effect snow back into Watertown. Given the greater
than normal spread in wind direction seen in model guidance, have
had to keep a wide area of higher POPS east of Lake Ontario and
spread out snow accumulations.

As far as storm total accumulations go, it still appears that the
highest amounts east of both lakes may reach the 1-2 foot range.
There is still a good deal of uncertainty about exactly where the
greatest amounts will fall however given the differences in band
placement during the second half of the event. Given this
uncertainty, expect adjustments in forecast snow amounts and
placement of highest amounts in future forecasts. The total
accumulation for the Buffalo to Batavia corridor is also quite
challenging and uncertain given the potential negatives with dry air
on Wednesday.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
A long wave upper trough remain entrenched over the Great Lakes
region through the period and likely through at least mid-December.
Ongoing lake effect snow at the start of the period on Friday will
continue to get shoved northward as the steering flow continues to
back ahead of approaching shortwave and will likely weaken within
increasing shear profiles. Model profiles continuing to suggest that
the lake effect potential will back off somewhat later Friday
through Saturday as this upper wave digs south of the region through
the mid-Atlantic States, and boundary layer flow becomes quite
southerly.

Behind this system, more arctic air looks to arrive across the lower
Great Lakes. It continues to look reasonable that another round of
significant lake effect snow will ramp up by Sunday into early next
week. Beyond that, expect additional chances for relatively light
snow with clipper passages through the rest of next week, and more
importantly additional chances for heavy lake effect snow as each
fresh batch of cold air arrives behind the clippers.

&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
Low-level wind shear, 45 knots at 2kft, will remain a concern at all
TAF sites through this morning, especially as surface winds diminish
some this morning as rain moves across the region.

Widespread rainfall will move across the region today, however,
flight conditions will remain primarily VFR for locations across the
lake plains, and MVFR at JHW in the higher terrain. As the rain
tapers off from west to east late this morning through the
afternoon, expect a brief period of MVFR to impact the TAF sites as
the cold front moves across the terminals, with IFR at JHW. By later
this evening and tonight, conditions will improve back to VFR with
MVFR at JHW. Winds will remain gusty (25 to 30 knots) at the TAF
sites through tonight.

Lake effect snow will start after midnight northeast of Lake Erie.
The band is initially expected to be south of KBUF, but may drift
north and impact KBUF with conditions near or below airport minimums
at times starting after 08Z or 09Z.

Outlook...

Wednesday...Areas of IFR in heavy lake effect snow northeast of
Lakes Erie and Ontario. Significant impacts possible at KBUF
and KART with conditions possibly below airfield minimums at
times. Mainly VFR outside lake effect.
Thursday...Areas of IFR in heavy lake effect snow east and
northeast of the lakes. Mainly VFR outside lake effect.
Friday and Saturday...VFR/MVFR with a chance of snow showers.

&&

.MARINE...
Small craft conditions will remain in place the lakes today with
stiff southerly winds ahead of an approaching strong cold front.
That cold front will slice across the region this afternoon and
evening, bringing gales to around 35 knots on the lakes. A gale
warning for Lake Erie starts at 21Z today, and 00Z on Lake Ontario.
The gale force winds will last through the night and into Wednesday
morning. In addition, southwest winds funneling up the St. Lawrence
Valley will bring small craft winds of 20 to 25 knots on the River.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Lakeshore Flood Warning from 11 PM this evening to 10 AM EST
     Wednesday for NYZ006-007.
     Winter Storm Watch from Wednesday morning through Friday
     morning for NYZ007-008.
     Winter Storm Watch from Wednesday evening through Friday
     morning for NYZ006.
     Winter Storm Watch from late tonight through Wednesday evening
     for NYZ001-002.
     Winter Storm Watch from Wednesday evening through late
     Thursday night for NYZ012-019-020-085.
     Winter Storm Watch from late tonight through late Thursday
     night for NYZ010-011.
MARINE...Small Craft Advisory until 4 PM EST this afternoon for LEZ040-
         041.
         Gale Warning from 4 PM this afternoon to 1 PM EST
         Wednesday for LEZ040-041.
         Small Craft Advisory until 7 PM EST Wednesday for LEZ020.
         Small Craft Advisory until 7 PM EST this evening for
         LOZ042>045.
         Gale Warning from 7 PM this evening to 1 PM EST Wednesday
         for LOZ042>045-062>065.
         Small Craft Advisory from 7 PM this evening to 1 PM
         EST Wednesday for SLZ022-024.

&&

SYNOPSIS...CHURCH
NEAR TERM...CHURCH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK/TMA
AVIATION...CHURCH
MARINE...CHURCH
Hazardous weather outlook, Dec 4, 7:54 PM EST, 7 hours 55 minutes before
Hazardous Weather Outlook
National Weather Service Buffalo NY
754 PM EST Mon Dec 4 2017

NYZ003>005-013-014-021-060100-
Monroe-Wayne-Northern Cayuga-Livingston-Ontario-Allegany-
754 PM EST Mon Dec 4 2017

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

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

The probability for 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

NYZ001-002-060100-
Niagara-Orleans-
754 PM EST Mon Dec 4 2017

...WINTER STORM WATCH IN EFFECT FROM LATE TUESDAY NIGHT THROUGH
WEDNESDAY EVENING...

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

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

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

   Winter Storm Watch.

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

NYZ019-085-060100-
Chautauqua-Southern Erie-
754 PM EST Mon Dec 4 2017

...WIND ADVISORY IN EFFECT UNTIL 4 AM EST TUESDAY...
...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH LATE
THURSDAY NIGHT...

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

.DAY ONE...Tonight.

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

   Wind Advisory.

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

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

   Winter Storm Watch.

After the first lake effect event is disrupted Friday into Saturday
by a wave of low pressure moving through the area, a second
significant lake effect event may develop for the beginning of next
week. There remains plenty of uncertainty at this time range with
the
details of band placement and intensity.

.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

NYZ010-011-060100-
Northern Erie-Genesee-
754 PM EST Mon Dec 4 2017

...WINTER STORM WATCH IN EFFECT FROM LATE TUESDAY NIGHT THROUGH LATE
THURSDAY NIGHT...

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

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

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

   Winter Storm Watch.

After the first lake effect event is disrupted Friday into Saturday
by a wave of low pressure moving through the area, a second
significant lake effect event may develop for the beginning of next
week. There remains plenty of uncertainty at this time range with
the details of band placement and intensity.

.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

NYZ012-020-060100-
Wyoming-Cattaraugus-
754 PM EST Mon Dec 4 2017

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

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

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

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

   Winter Storm Watch.

After the first lake effect event is disrupted Friday into Saturday
by a wave of low pressure moving through the area, a second
significant lake effect event may develop for the beginning of next
week. There remains plenty of uncertainty at this time range with
the details of band placement and intensity.

.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

NYZ007-008-060100-
Jefferson-Lewis-
754 PM EST Mon Dec 4 2017

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY MORNING THROUGH
FRIDAY MORNING...

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

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

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

   Winter Storm Watch.

After the first lake effect event is disrupted Friday into Saturday
by a wave of low pressure moving through the area, a second
significant lake effect event may develop for the beginning of next
week. There remains plenty of uncertainty at this time range with
the details of band placement and intensity.

.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

NYZ006-060100-
Oswego-
754 PM EST Mon Dec 4 2017

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH
FRIDAY MORNING...

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

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

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

   Winter Storm Watch.

After the first lake effect event is disrupted Friday into Saturday
by a wave of low pressure moving through the area, a second
significant lake effect event may develop for the beginning of next
week. There remains plenty of uncertainty at this time range with
the details of band placement and intensity.

.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-SLZ022-024-060100-
Upper Niagara River and Buffalo Harbor-Lower Niagara River-
Saint Lawrence River from Cape Vincent to Ogdensburg-
Saint Lawrence River from Ogdensburg to Saint Regis-
754 PM EST Mon Dec 4 2017

This Hazardous Weather Outlook is for portions of Lake Erie, Lake
Ontario and Saint Lawrence River.

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

The probability for 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

LOZ042>045-062>065-060100-
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-
754 PM EST Mon Dec 4 2017

...GALE WARNING IN EFFECT FROM 7 PM TUESDAY TO 1 PM EST WEDNESDAY...

This Hazardous Weather Outlook is for portions of Lake Ontario.

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

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

   Gale Warning.

.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

LEZ040-041-060100-
Lake Erie nearshore waters from Ripley to Dunkirk-
Lake Erie nearshore waters from Dunkirk to Buffalo-
754 PM EST Mon Dec 4 2017

...GALE WARNING IN EFFECT FROM 4 PM TUESDAY TO 1 PM EST WEDNESDAY...

This Hazardous Weather Outlook is for portions of Lake Erie.

.DAY ONE...Tonight.

The probability for widespread hazardous weather is low.

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

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

   Gale Warning.

.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

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 4, 7:35 PM ESTWind AdvisoryBUFChautauqua, Erie8 hr
Dec 4, 7:53 PM ESTGale WarningBUF41 hr
Dec 5, 1:01 PM ESTLake Effect Snow WarningBUFCattaraugus, Chautauqua, Erie, Jefferson, Lewis, Wyoming68 hr
Dec 5, 1:01 PM ESTWinter Weather AdvisoryBUFErie, Genesee33 hr

Nearby

Lakeshore Flood Warnings in New York, 2017Every lakeshore flood warning in 2017

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.