Classification of All Snow Storms (Winter 2006-2007 to Winter 2008-2009) - 54 Storms

Poga Mountain, North Carolina ( Elevation: 1137 m)

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Storm Summary of 2006-2007 Winter Season (November - April)

Storm Summary of 2007-2008 Winter Season (November - April)

Storm Summary of 2008-2009 Winter Season (November - April)

SWE = Snow-water equivalent

** = trend 24 hours before storm (Winter 2006-2007)
** = trend 6 hours before storm (Winters 2007-2008 & 2008-2009)
Tall (> 4.0 km AGL)   Continuity for Storm Maturity
Borderline ( 2.5-4.0 km AGL)   Scattered: Several Breaks
Shallow (< 2.5 km AGL)   Classification of All Snow Storms
CL
A 500 mb cutoff low moves across the region (often slow & sometimes quasi-stationary) with a surface cyclone that often moves or remains inland of coast ( e.g. 3/19/96), and doesn?t redevelop along the East Coast. Note that some strong MAs are connected with upper-level cyclogenesis as they move up the East Coast, but would still be considered MAs. Many MB's are also connected with an upper-level cyclone, but there is secondary cyclogenesis along the coast and the system is progressive.The CL type, in most cases, is distinguished on a surface analysis from the other types by the cyclone exhibiting one of the following: a) development inland as wave on a front, b) Passage across the southern Appalachians, c) NE or NNE movement inland across the Gulf Coast unlike most Miller A's
GU
Gulf - Surface wave or weak low moves along Gulf and does not turn northward up the East Coast like a MA. Note that this implies that Gulf moisture (via isentropic lifting) is the dominant contributor in contrast to a Miller A, where Atlantic moisture provides a significant secondary contribution (e.g. via cold conveyer belt).
LC
Surface cyclone develops between the lee of the Appalachians (e.g. lee cyclogenesis) and the near shore waters of the Atlantic Coast (e.g. Cape Hatteras low). Excluded from this category are MBSs where there is a weakening "primary" low present to the west and surface cyclones that are tightly coupled to a slow-moving 500 mb cyclone (i.e. CL category)
MA
Miller A - cyclone or series of small cyclones pass south and then east of area (i.e. they turn towards the northeast and move/deepen along/near East Coast).
MAB
Miller A/B - Cyclones that display both Miller A and Miller B characteristics. These Miller "B-like" systems would always be MBSs (i.e. redeveloping cyclone to the south and east).
MBN
Miller B to the north - Filling cyclone NW of region redevelops NE of the area (i.e. secondary cyclogenesis off of the NE Atlantic Coast). Occluded frontal passages frequently occur in the situation. The NE Atlantic Coast is defined as the area north of Hatteras.
MBS
Miller B to the south - Filling cyclone SW to NW of region redevelops E or SE of the area (i.e. secondary cyclogenesis off of the SE Atlantic Coast). MBSs show a much stronger connection with snowfall ahead the system as compared to the MBNs. The SE Atlantic Coast is defined as the area south of Hatteras.
NE
Northeastward tracking low passes to the north of area. The region is frequently in the warm sector and subject to a rapid temperature fall immediately behind a cold front.
NEb
Snow associated with a moist (e.g. Gulf origin) southwesterly low-level flow ahead of an eastward moving disturbance in the northern jet stream (i.e. north of GSNP). Often the precipitation region is along a relatively narrow NE-SW oriented axis that may extend from the Gulf to the Ohio Valley/Great Lakes region. GU events would be distinguished by a east-west oriented frontal boundary along Gulf Coast/Gulf of Mexico and precipitation that is confined to the southern U.S. (i.e. does not extend into the Ohio River Valley).
SE
Southeastward-tracking clipper that passes north or across the region. If clipper passes south/west of the region a Miller B transition may be occurring in which case it would be classified as such (e.g. see Blacksburg example of the Miller B).
SF
In all cases a stationary front was present overhead or immediately south thus some isentropic lift and/or low-level convergence. In many cases it was tied to a "lead" wave propagating around a larger upstream trough. In some of these cases, the lift may have been contributed by the right entrance region of downstream jet streak. Also there was a surface anticyclone to the NE with an associated CAD signature in the Piedmont.
U
Denotes NW upslope snow. In most cases it will be tied to one of the cyclone patterns identified in section 1 above; however, there will be a few cases in which no clearly defined surface cyclonic pattern exists (e.g. upslope sets up a day or more after a cyclonic system passes by - see 2/12-213/96). These events would simply be denoted by a "U".
X
Unclassified
Trends
Wind Direction
Temperature
RH
Pressure
Year
Month
Day
Type
Class
AGL
Continuity
Start Time (UTC)
Duration (hrs)
Avg. Temp. (°C)
Avg.
At Snow Storm Maturity
Wind Speed (m/s)
Snowfall (in)
SWE (in)
before**
during
before**
during
before**
during
2008
1
24
Snow
LC/SEu
Shallow
Scattered
12:00
14
-7.1
NW
NW
4.7
0.8
0.04
decreasing
decreasing
increasing
decreasing
flat
increasing
2006
11
11
Rain to Snow
LCu
Tall to Shallow
Scattered
20:00
22
2.7
NW
NW
4.4
0.3
0.14
increasing
decreasing
up - down
flat
decreasing
increasing
2007
01
28
Snow
LCu
Tall to Shallow to Borderline
Scattered
08:00
19
-6.0
NW
NW
4.3
2.2
0.14
up - down
decreasing
increasing
decreasing
decreasing
flat
2007
04
07
Snow
LCu
Borderline to Shallow
Continuous
00:00
21
-8.0
NW
NW
5.0
5.8
0.32
down - up
decreasing
down - up
decreasing
decreasing
increasing
2008
2
14
Very Light Snow
LCu
Unknown
Unknown
0:00
3
-8.1
W
NW
5.4
0.1
0.03
decreasing
decreasing
decreasing
flat
increasing
increasing
2007
04
14
Rain to Snow
MABu
Tall to Borderline
Scattered
00:30
52.5
7.0
SW
NW
3.9
4.4
0.48
down - up
up - down
up - down
increasing
increasing
decreasing
2008
3
8
Rain to Snow
MABu
Tall to Shallow
Scattered
1:30
25.5
0.6
SW
NW
4.4
1.5
0.11
increasing
increasing
increasing
decreasing
decreasing
increasing
2009
03
01
Virga to Snow
MABu
Tall to Shallow
Continuous
12:00
27.5
-5.3
NW
NW
7.9
11.1
0.94
decreasing
decreasing
increasing
decreasing
decreasing
down - up
2007
12
15
Rain to Snow
MBNu
Tall to Shallow
Scattered
20:00
33.5
-1.9
SE
S
4.8
4.1
0.11
decreasing
decreasing
increasing
decreasing
decreasing
down - up
2008
1
1
Snow
MBNu
Shallow
Scattered
8:00
23
-9.4
NW
NW
4.6
4.0
0.13
increasing
decreasing
decreasing
increasing
decreasing
increasing
2007
02
13
Rain to Snow
MBSu
Tall to Shallow
Scattered
20:00
18.5
2.8
S
NW
2.6
1.3
0.05
increasing
decreasing
increasing
flat
decreasing
down - up
2007
12
19
Snow
NEb/Xu
Borderline to Shallow
Scattered
9:30
5
-0.4
SW
W
2.0
trace
0.01
increasing
increasing
flat
increasing
decreasing
flat
2007
02
02
Snow
NEu
Borderline to Shallow
Scattered
17:00
18
-6.1
W
NW
3.9
0.4
0.05
flat
decreasing
increasing
decreasing
decreasing
increasing
2008
1
13
Virga to Rain to Snow
NEu
Tall to Shallow
Scattered
13:00
28
-0.8
SW
NW
3.0
0.6
0.04
decreasing
decreasing
increasing
decreasing
decreasing
flat
2008
3
4
Rain to Light Snow
NEu
Tall to Shallow
Continuous
12:00
24
6.8
SW
NW
4.0
trace
0.01
increasing
decreasing
increasing
flat
decreasing
down - up
2008
12
1
Snow to Rain
NEu
Borderline to Tall to Shallow
Scattered
08:30
34.5
-3.3
SW
SW
8.6
2.9
0.15
decreasing
decreasing
decreasing
up - down
increasing
increasing
2009
01
06
Rain to Snow
NEu
Tall to Borderline
Scattered
00:00
56
5.1
SW
NW
9.6
4.2
0.29
up - down
decreasing
increasing
down - up
decreasing
down - up
2009
01
13
Rain to Snow
NEu
Shallow
Continuous
21:30
15
-3.0
W
NW
8.7
0.7
0.04
up - down
decreasing
down - up
up - down
decreasing
increasing
2009
02
22
Virga to Snow
NEu
Tall to Shallow
Scattered
03:00
13
-7.1
W
W
9.1
1.6
0.05
decreasing
decreasing
increasing
increasing
decreasing
increasing
2007
01
09
Virga to Snow
SEu
Tall to Borderline
Scattered
12:00
16
-3.2
W
NW
4.0
4.0
0.31
decreasing
decreasing
decreasing
increasing
up - down
increasing
2007
02
06
Snow
SEu
Tall to Borderline
Continuous
18:30
12.5
0.7
SW
S
3.9
0.3
0.03
down - up
increasing
increasing
up - down
flat
decreasing
2007
02
17
Virga to Snow
SEu
Tall to Shallow
Scattered
11:00
36
-7.3
SW
NW
3.6
5.5
0.23
down - up
up - down
decreasing
increasing
up - down
down - up
2007
12
5
Virga to Rain to Snow
SEu
Tall to Borderline
Continuous
06:00
21
0.9
SW
W
3.0
0.2
0.09
increasing
up - down
flat
increasing
decreasing
down - up
2008
4
29
Rain to Snow
SEu
Borderline to Tall to Borderline
Scattered
1:00
6.5
3.2
W
NW
3.6
trace
0.03
up - down
decreasing
down - up
up - down
increasing
up - down
2009
01
17
Rain to Snow
SEu
Shallowto Borderline to Shallow
Scattered
22:00
86
-6.6
S
NW
16.9
8.1
0.36
increasing
up - down
down - up
increasing
decreasing
decreasing
2009
02
03
Virga to Snow
SEu
Shallow to Tall to Shallow
Scattered
16:00
32
-12.7
W
W
8.0
6.4
3.7
down - up
decreasing
decreasing
increasing
flat
increasing
2006
11
19
Rain to Snow
U
Borderline
Scattered
08:00
30
-1.1
NW
NW
2.5
1.2
0.23
up - down
decreasing
down - up
flat
flat
increasing
2006
12
07
Virga to Snow
U
Borderline to Shallow
Continuous
18:00
7
-5.8
NW
NW
6.0
2.0
0.09
decreasing
decreasing
increasing
up - down
flat
increasing
2007
01
23
Rain / Freezing Rain
U
Shallow
Scattered
23:00
7
-5.4
SW
--
1.2
--
--
decreasing
decreasing
decreasing
down - up
increasing
flat
2007
02
09
Virga to Snow
U
Tall to Borderline
Continuous
17:00
6
-6.1
NW
NW
2.8
0.2
0.01
down - up
decreasing
up - down
increasing
decreasing
flat
2007
03
04
Snow
U
Shallow
Continuous
04:30
14
-7.5
W
NW
4.5
0.8
0.01
decreasing
down - up
increasing
decreasing
flat
increasing
2007
03
15
Rain to Snow
U
Tall to Shallow to Borderline
Continuous
18:30
45.5
3.2
W
NW
3.2
1.8
0.10
decreasing
decreasing
increasing
flat
decreasing
decreasing
2007
11
14
Rain to Snow
U
Tall to Shallow
Scattered
23:00
25
4.7
SW
NW
3.5
0.1
0.01
increasing
decreasing
decreasing
up - down
decreasing
down - up
2007
11
22
Rain to Snow
U
Tall to Shallow
Scattered
00:30
25
9.4
SW
NW
2.2
trace
0.02
decreasing
decreasing
increasing
increasing
decreasing
down - up
2008
1
15
Snow
U
Shallow
Scattered
11:30
4.5
-8.4
NW
NW
4.9
0.2
0.01
decreasing
increasing
flat
increasing
flat
increasing
2008
2
19
Virga to Snow to Virga
U
Borderline
Scattered
1:30
21
-2.9
W
W
4.3
0.1
0.01
decreasing
down - up
decreasing
flat
increasing
increasing
2008
2
26
Virga to Rain to Snow
U
Tall to Shallow
Scattered
4:30
63
-4.3
W
NW
4.4
8.3
0.39
decreasing
decreasing
increasing
up - down
decreasing
increasing
2008
3
24
Virga to Snow
U
Borderline to Shallow
Scattered
17:00
10
-3.1
NW
NW
3.7
0.4
0.02
increasing
decreasing
decreasing
increasing
increasing
increasing
2008
4
13
Snow
U
Borderline to Shallow
Scattered
18:00
11
2.7
NW
NW
4.4
0.3
0.06
flat
decreasing
flat
increasing
increasing
increasing
2008
4
14
Snow to Virga
U
Borderline
Scattered
16:30
14.5
-0.9
NW
NW
2.9
0.4
0.08
increasing
decreasing
decreasing
increasing
increasing
increasing
2008
12
4
Rain to Snow
U
Shallow to Tall to Shallow
Continuous
20:00
8
1.3
W
NW
6.3
0.1
0.01
decreasing
decreasing
increasing
flat
up - down
increasing
2008
12
12
Rain to Snow
U
Shallow
Scattered
20:00
10
-5.6
W
W
8.7
0.2
0.02
decreasing
decreasing
flat
decreasing
increasing
increasing
2006
12
26
Rain to Snow
Xu
Borderline to Shallow
Scattered
07:00
19
-0.4
W
NW
4.0
0.5
0.12
up - down
decreasing
increasing
flat
decreasing
increasing
2007
01
25
Snow
Xu
Shallow
Continuous
13:30
7.5
-5.4
W
NW
4.4
1.0
0.03
decreasing
down - up
increasing
decreasing
decreasing
flat
2007
02
04
Virga to Snow
Xu
Borderline
Continuous
13:00
8
-5.6
W
NW
4.8
0.4
0.01
down - up
decreasing
up - down
increasing
increasing
flat
2008
1
19
Virga to Snow to Virga
Xu
Tall
Scattered
5:30
21
-4.0
W
NW
2.3
0.4
0.04
decreasing
decreasing
decreasing
increasing
increasing
decreasing
2008
12
11
Rain to Snow
Xu
Tall to Shallow
Scattered
05:30
55
9.3
SW
NW
10.7
0.8
0.11
increasing
decreasing
flat
down - up
decreasing
decreasing
2009
01
06
Rain to Snow
Xu
Tall to Borderline
Scattered
00:00
56
5.1
SW
NW
9.6
4.2
0.29
up - down
decreasing
increasing
down - up
decreasing
down - up
2009
02
02
Virga to Snow to Virga
Xu
Tall
Continuous
17:00
8
-0.3
W
W
3.7
1.1
0.12
up - down
decreasing
down - up
increasing
decreasing
flat

Version 1.2, 18 August 2011

web page credits: Micheal Tai Bryant, Sandra Yuter, L. Baker Perry

This research is a collaboration between the
Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University
and the Department of Geography and Planning, Appalachian State University

This material is based upon work supported by the National Science Foundation under Grant No. 0544766. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).

contacts:
Dr. Sandra Yuter seyuter@ncsu.edu

Dr. L. Baker Perry perrylb@appstate.edu