Download Lake/Ocean Effect Snow

All About Lake-Effect Snow
Tom Niziol
Winter Weather Expert
The Weather Channel
CoCoRaHs Seminar November 12th, 2015
Outline
• Definition of Lake/Ocean Effect Snow (LOES)
• Favored Locations in North America/World
• Conceptual Model of LOES
Photo by Tom Niziol
Lake Effect Snow – NWS Buffalo Parking Lot
Outline
• Morphology / Snow Band Classification
• Fun Look At What Heavy Snow Looks Like
Photo by Tom Niziol
We lose most of our observers when it snows
What Does Lake-Effect Snow Look Like ??
Lake/Ocean-Effect Snow
• Occurs when cold air moves over a relatively
warm body of water.
• In most cases, snow develops in post cold
frontal conditions typically favoring fair (clear)
weather on a synoptic scale.
Lake/Ocean-Effect Snow
“Fair Weather” Or Not ??
37°F
18°F
-2°F
A
B
Lake/Ocean-Effect Snow
“Fair Weather” Or Not ??
A
B
Barney Wiggin, former MIC at NWS Buffalo, said it best when he claimed that the
weather often "clears up stormy" to the lee of the Great Lakes during the winter.
Question 1
True or False
• Does Lake-effect Snow Only Occur In The
Great Lakes ???
True
False
12%
88%
Where in North America Does It Occur
Where in the World Does It Occur
Where in the World Does It Occur
Question 2
True or False
• There Is Such A Thing As Lake-effect Rain
True
False
93%
7%
What Is The Lake-Effect Snow Season
Graph by Tom Niziol
Seasonality – When Does It End ??
Question 3
• Which Great Lake Develops The Most Ice
Cover
Superior 36%
Michigan 0%
Huron
7%
Erie
39%
Ontario 18%
Ice Cover On the Great Lakes
Lake Huron
Lake Ontario
Lake Michigan
Lake Erie
Great Lakes Bathymetry
Seasonal Ice Cover On the Great Lakes
January 1-7
Seasonal Ice Cover On the Great Lakes
January 15-21
Seasonal Ice Cover On the Great Lakes
February 8-14
Seasonal Ice Cover On the Great Lakes
March 1-7
Seasonal Ice Cover On the Great Lakes
March 15-21
Seasonal Ice Cover On the Great Lakes
April 8-14
Seasonal Snowfall For The Great Lakes
Question 3
• What is the highest annual snowfall recorded
in one winter season in the Great Lakes
Region?
960” 13%
466” 63%
120” 23%
74”
4%
On What Scale Does LOES Occur?
• Horizontal scales are Meso-alpha.
• 12 mi.– 120 mi. as defined by Orlanski (1975).
• Vertical scale
• Usually confined to < 10,000 ft.
• Temporal scale
• Generally on the order of several hours, though
multi-day events are not unusual.
Horizontal Scale
– Meso-alpha (12mi – 120mi) Orlanski (1975).
North Wall of Lake Effect Snow Band Moving Across
the City of Buffalo, NY Off Lake Erie
Photo by Gordon Scherer
Vertical Scale
Lake Effect Convection and its Bigger Summertime Convective Cousin
•
Lake Effect Snow Event
•
Summertime Convection
•
•
Modified Parcel Temp / Dewpoint
Lake-Induced CAPE ~300J/kg
•
•
Non-modified Temp / Dewpoint
CAPE > 2000J/kg
Vertical Scale
Lake Effect Convection and its Bigger Summertime Convective Cousin
This storm produced
nearly 70in. of snow
over a 3 day period.
•
Lake Effect Snow Event
•
Summertime Convection
•
•
Modifed Parcel Temp / Dewpoint
Lake-Induced CAPE ~300J/kg
•
•
Non-modified Temp / Dewpoint
CAPE > 2000J/kg
Temporal Scale
Anywhere From a Few Hours to Several Days
Temporal Scale
Anywhere From a Few Hours to Several Days
126” (320cm.)
82” (208cm.)
50 miles
LOES
Meso-Alpha Scale Cold Season Convection
Three areas of snowcover downwind of Lake Erie mark this 3-part storm
Lake Huron
Lake Ontario
Ontario
New York
Lake Erie
Ohio
Pennsylvania
Conceptual Model – Lake Snow Formation
Cold Air Crossing Warm Water
(Disney World – Orlando, FL)
Cold Air Crossing Warm Water
(St. Regis Pond – Adirondack Park, NY)
Conceptual Model – Lake Snow Formation
Inversion
Up Close and Personal With LOES
NOAA-16 Satellite Image
Aircraft Trajectory
The Real Thing
Photo by T. Niziol
The Real Thing
Photo by T. Niziol
The Real Thing
Photo by T. Niziol
The Real Thing
Photo by T. Niziol
The Real Thing
Photo by T. Niziol
The Real Thing
Photo by T. Niziol
Development of Local Instability
Modification of Lower Atmospheric Thermodynamic Profile
37°F
-2°F
14°F
A
B
Development of Local Instability
Modification of Lower Atmospheric Thermodynamic Profile
A
GRB
B
APX
Development of Local Instability
Inversion
Inversion Hgt
Hgt 900mb
800mb
Air
Air Temp
Temp -18C
-12C
Dewpoint
Dewpoint -20C
-13C
Development of Local Instability
Net Change
Inversion Hgt +100mb
Air Temp +6C
Dewpoint +7C
Morphology of Snow Bands
Attempts to Classify
Snow Band Types
Horizontal Roll
Multiple Banding
Single Band
Land Breeze Banding
Which Factors Are
Responsible For So Many
Types of Banding?
MesoLow
Multi-Lake Banding
Morphology of Snow Bands
Attempts to Classify
Snow Band Types
Horizontal Roll
Multiple Banding
Single Band
Land Breeze Banding
• The shape of the water body
• Orientation of the water body
with respect to wind direction
MesoLow
•Wind speed and shear within
the mixed layer
Multi-Lake Banding
Morphology of Snow Bands
Multiple Bands – Horizontal Roll Convection
Horizontal Roll Multiple Banding
Morphology of Snow Bands
Multiple Band - Horizontal Roll Convection
• Counter-rotating vortices in
the boundary layer.
• Major axes aligned with the
mean boundary layer wind.
• Significant speed shear
and very little directional
shear.
• Wavelength (updraft to
updraft) is about three
times the height of the
Boundary Layer.
Morphology of Snow Bands
Multiple Bands – Horizontal Roll Convection
Prevailing BL Wind
Atlantic Ocean
Morphology of Snow Bands
Multiple Bands – Horizontal Roll Convection
Prevailing BL Wind
Multiple Bands – Horizontal Rolls
Visible Satellite and WSR-88D Composite Reflectivity
Prevailing Flow
Horizontal roll convection producing multiple bands under prevailing
westerly flow across the short fetch of Lake Michigan
Multiple Bands - Sea of Japan
MSLP – Feb 2, 2005 00z
China
Japan
Multiple Bands - Sea of Japan
Visible Satellite
Multiple Bands - Sea of Japan
Visible Satellite
Multiple Bands - Sea of Japan
Radar
Saporro
Multiple Bands - Sea of Japan
Tokyo
Multiple Bands – Gulf of St Lawrence
850mb Height
Multiple Bands – Gulf of St Lawrence
NASA MODIS Polar Orbiter Satellite
NASA MODIS
2/7/13
Multiple Bands – Gulf of St Lawrence
NASA MODIS Polar Orbiter Satellite
NASA MODIS
2/7/13
Multiple Bands – Gulf of St Lawrence
NASA MODIS Polar Orbiter Satellite
NASA MODIS
2/7/13
Multiple Bands – Gulf of St Lawrence
NASA MODIS Polar Orbiter Satellite
NASA MODIS
2/7/13
Multiple Bands – Cape Cod
850mb – Jan 14, 1999 12z
Multiple Bands – Cape Cod
850mb – Jan 14, 1999 12z
Multiple Bands – Cape Cod
925mb – Jan 14, 1999 12z
Multiple Bands – Cape Cod
Jan 14, 1999 12z
850mb
925mb
Multiple Bands – Cape Cod
Jan 14, 1999 12z
850mb
925mb
-18C
-10C
-5C
-15C
10,000 ft.
7,500 ft.
4,500 ft.
2,000 ft.
Multiple Bands – Cape Cod
MSLP – Jan 14, 1999 12z
Multiple Bands – Cape Cod
MSLP – Jan 14, 1999 12z
Multiple Bands – Cape Cod
KBOX Radar Reflectivity
Multiple Bands – Cape Cod
CHH Sounding
4200ft = 30⁰F
3600ft = 3⁰F
Waldstreicher, J.S., 2002: A foot of snow from a 3000-foot cloud: The Ocean-Effect
Snowstorm of 14 January 1999. Bull. Amer. Meteor. Soc., 83, 19–22.
Morphology of Snow Bands
Single Bands
Horizontal Roll
Multiple Banding
Single Band
Land Breeze Banding
Single Band
MesoLow
Multi-Lake Banding
Morphology of Snowbands
Single Band Development
Single Band
Lake Huron
Single Band
Lake Ontario
Morphology of Snowbands
Wide Lake – Multiple Rolls
Land Breeze
Prevailing Wind
Cold
Warm
Morphology of Snowbands
Narrow Lake – Single Band
Land Breeze
Prevailing Wind
Morphology of Snowbands
Thermal Convergence - Single Band Development
Morphology of Snowbands
Consolidation Into One Band
Single Band Development
Visible Satellite Imagery
Prevailing Flow
Note the Single Cloud Band Extending Along the Long Axis of Lake Ontario
Single Band Development
Visible Satellite and WSR-88D 0.5° Mosaic Radar Reflectivity
Radar reflectivity exceeds 35dBz east of Lake Ontario
Single Band Development
METAR Reports – Convergence Zone
Pt. Petre – NW20G26 kts.
Convergence
Oswego – SW16G32 kts.
Surface Reports Over Eastern Lake Ontario Suggest Strong Convergence
Wind Parallel – Single Dominant Band
Wind Parallel – Single Dominant Band
Lake Effect Storm “Dalmation” – 37 inches in 12 hours
January 20, 2008 1200GMT – 2100GMT
NAM12 Sfc Reflectivity – WSR-88D Montague 0.5 Reflectivity
January 20, 2008 2100GMT
NAM12 Sfc Reflectivity
January 20, 2008 2100GMT
NAM12 Cross-Section (Omega and Vertical Circulation)
NAM12 Photo by Tom Niziol
Multiple Horizontal Rolls
vs.
Large, Well-developed Single Band
Single Band – Wind Parallel
(Lake Erie Lancaster, NY)
North Wall of Lake Effect Snow Band Moving Across
the City of Buffalo, NY Off Lake Erie
Photo by Gordon Scherer
Snow Depth After 5-Day Single Band
Lake Effect Storm, WFO Buffalo
Photo by Tom Niziol
Single Band Development – Gulf of Bothnia
Parallel to long axis of the body of water
Single Band Development – Gulf of Bothnia
November 1-2, 2006
MSLP
850mb
L
L
H
L
L
L
Single Band Development – Gulf of Bothnia
Parallel to long axis of the body of water
Single Band Development – Gulf of Bothnia
Mosaic Radar Loop
Single Band Development – Chesapeake Bay
850mb Height
Single Band Development – Chesapeake Bay
850mb Temperature
-9C to -12C
Single Band Development – Chesapeake Bay
Parallel to long axis of the body of water
Morphology of Snowbands
Thermal Convergence - Land Breeze Snowbands
Morphology of Snowbands
Land Breeze Snowbands
Land Breeze
Air Temp: -18°C
Water Temp: +3°C
Cloudband over Lake Erie that has developed under nearly calm
synoptic scale wind and significant air-water temperature differences
leading to a well-developed local land breeze circulation.
Thermal Convergence
Thermal Convergence
Under weak NE synoptic flow, the general shape and
orientation of the body of water often
dictates the type of snowband that develops.
Niziol (1995)
Thermal Convergence
January 8, 1981
Temperatures
Air ~ -21C
Lake water ~ +3C
Lake Michigan MesoLow Under Calm Surface Winds
and significant land-lake temperature differences.
Niziol (1995)
A “Spin-off” of a Mesolow
2008 NWA Conference - Louisville, KY
Sam Lashley – National Weather Service Northern Indiana
Jon Hitchcock – National Weather Service Buffalo, NY
Feb 20, 2008
20 February, 2008 – Radar Mosaic
Feb 20, 2008
What Does Lake-Effect Snow Look Like ??
North Wall Lake-Effect Snow Band
Buffalo NY – November 2014
That’s A Lot of Snow
Montague Inn – Tug Hill
East of Lake Ontario
Snow Lovers Paradise
Who’s That Knocking At My Door…
This Is Gonna Be A Tough Day…
OK I Am Outside, Now What !!!
Photo by Tom Niziol
Nothing Like A Cozy Evening Next To The Fire