A Long-Lived Intense Continental-Scale Front: 28 February-4 March 1972 by

1
A Long-Lived Intense Continental-Scale Front 28
February-4 March 1972by

• Lance F. Bosart
• Department of Earth and Atmospheric SciencesThe
  University at Albany/SUNY1400 Washington
  AvenueAlbany, NY 12222
• Sixth Northeast Regional Operational Workshop
  Albany, New York,Tuesday, November 2, 2004

2
Purpose

• Document the structure and life cycle of an
  intense long-lived surface front that stretched
  from the Rockies to New England and southward to
  the Gulf of Mexico.
• Document the diurnal variation in frontal
  structure and intensity.
• Relate frontal evolution and frontal
  disturbances to upper-level features.

3
0
0
5
10
15
5
20
10
15
20
Frontogenesis

Frontolysis
4
Land
10
5
0
x
y
0
Water
20
10
5
2100 UTC9 Nov 2003
0600 UTC 10 Nov 2003
(a)
(b)
1200 UTC 10 Nov 2003
1800 UTC 10 Nov 2003
(c)
(d)
6
Attributes of the 28 February - 4 March 1972
Frontal Case

• Temperature contrast exceeds 50C
• Excellent example of frontal-mountain
  interaction
• Abrupt onset of equatorward motion east of the
  Rockies
• Absence of significant cyclogenesis despite
  intense thermal contrast
• Flat frontal waves are common
• Significant diurnal variation in frontal
  intensity occurs

7
Frontal Isochrones 0000 UTC 28 Feb - 1200 UTC 3
Mar 1972
00Z/28
12Z/28
00Z/29
12Z/29
00Z/1
12Z/3
12Z/1
00Z/2
00Z/3
12Z/2
8
28 Feb - 3 Mar 1972
9
Snow Cover (cm) 1200 UTC 28 Feb 72
10
0000 UTC 28 February 1972
a) b)
c) d)
11
0000 UTC 1 March 1972
a) b)
c) d)
12
0000 UTC 3 March 1972
a) b)
c) d)
13
0000 GMT 28 February 1972
0600 GMT 28 February 1972
1200 GMT 28 February 1972
1800 GMT 28 February 1972
(a)
(b)
(c)
(d)
0000 GMT 29 February 1972
0600 GMT 29 February 1972
1200 GMT 29 February 1972
1800 GMT 29 February 1972
(e)
(f)
(g)
(h)
14
72775 (GTF)
0000 UTC 28 Feb72 1200 UTC 28 Feb72 0000 UTC 29
Feb72
Pressure (hPa)
Temperature (C)
15
(T)
GTF CTB GFA
(P)
(T)
1008
(P)
(T)
5
1004
Altimeter Setting (hPa)
0
1000
-5
Temperature (C)
996
-10
-15
-20

CTB
GTF
00
02
04
06
08
10
12
14
16
18
20
22
00
29 February 1972 (UTC)
16
0600 GMT 28 February 1972
1800 GMT 28 February 1972
0000 GMT 28 February 1972
1200 GMT 28 February 1972
(a)
(b)
(c)
(d)
0000 GMT 29 February 1972
0600 GMT 29 February 1972
1200 GMT 29 February 1972
1800 GMT 29 February 1972
(e)
(f)
(g)
(h)
17
(a)
(b)
(d)
(c)
18
(No Transcript)
19
(a)
(b)
(c)
(d)
20
72451 DDC 720301/0000 720301/1200
Pressure (hPa)
Temperature (C)
21
3h Pressure Change (hPa)
(a)
(b)
1800 UTC 29 Feb'72
2100 UTC 29 Feb'72
0000 UTC 1 Mar'72
0300 UTC 1 Mar'72
(c)
(d)
22
20
-20
-10
-10
16
5
12
08
-5
0
04
00
04
5
10
20
08
00
04
12
15
25
(a)
96
0000 UTC 1 March 1972
28
24
-20
-15
16
12
-5
0
08
-10
08
00
L
04
10
08
04
20
92
04
(b)
15
0600 UTC 1 March 1972
23
(a)
(b)
24
(T)
DSM OTM CID
(P)
(T)
(P)
20
(T)
(P)
1004
Temperature (C)
1002
15
Altimeter Setting (hPa)
1000
10
998
996
5
0
DSM
OTM
CID
(a)
21
00
03
06
09
12
UTC 29 February
1 March
1972
25
(T)
20
ORD NBU
(P)
(T)
(P)
1006
15
1004
Temperature (C)
Altimeter Setting (hPa)
10
1002
1000
5
998
0
NBU
ORD
21
00
06
09
03
12
UTC 29 February
1 March
1972
26
???? C (100 km)-1
100W 30-50N
0000
1200
0000
1200
0000
1200
28 29
1
February 1972 March
Time (UTC)
27
C (100 km)-1 (3h)-1
28
16
(a)
(b)
1200 UTC 2 March 1972
29
(T)
ALB GFL
(P)
15
(T)
(P)
10
Temperature (C)
1012
1010
5
1008
Altimeter Setting (hPa)
0
1006
1004
-5
1002
DSM
ALB
(a)
12
14
16
18
22
20
04
10
00
02
06
08
UTC 1 March
2 March
1972
30
02 Mar 1972 0000 UTC 03 Mar
1972 0000 UTC
Pressure (hPa)
Pressure (hPa)
PWM CAR
Temperature (C)
Temperature (C)
31
(T)
1014
NZW PWN
(P)
15
(T)
(P)
1012
10
1010
Altimeter Setting (hPa)
Temperature (C)
1008
5
1006
0
1004
-5
PWM
NZW
(b)
20
22
00
06
08
10
14
18
02
04
12
16
UTC 2 March
3 March
1972
32
(No Transcript)
33
(No Transcript)
34
300 hPa 50 ms-1 Isotachs
35
(No Transcript)
36
(No Transcript)
37
Summary

• Large-scale environment favors the accumulation
  of bitterly cold air in Canada
• Arctic surge east of the Rockies occurs after lee
  cyclogenesis
• Dynamic anticyclogenesis over Canada facilitates
  arctic surge
• Frontal intensity varies diurnally in response to
  differential diabatic heating
• Three types of cyclogenesis events are observed
• a) flat frontal waves that develop with no
  obvious
• upper-level support
• b) flat frontal waves that form in
  jet-entrance regions
• c) weak-to-moderate frontal cyclones
  that form ahead
• of upper-level troughs