00Z 10 June 13Z 11 June 2003

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00Z 10 June 13Z 11 June 2003
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Upscale Influences of MCSs
200 mb Analysis LFM Forecast
12 UTC 7 May, 1978
Maddox and Fritsch 1981 JAM
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Trier et al. MWR 2000
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Trier et al. MWR 2000
1998
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Trier et al. MWR 2000
1998
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Trier et al. MWR 2000
1998
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Trier et al. MWR 2000
1998
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IOP 1
200 km
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IOP 8
Mean Wind Profile
900 hPa
1730 UTC 11 June
dBz
70
60
50
X
40
30
20
10
Widespread Instability
m/s
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IOP 18 (6 July)
02 UTC
MN
SD
IA
NE
04 UTC
06 UTC
Pressure
08 UTC
10 UTC
300 km
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IR Satellite from 27-28 May, 1998
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Radar Composite 28 May 1998
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MCV Induced Lifting and Destabilization
Fritcsh et al. 1994, MWR
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Low-Level Jet Scenario
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Finite Squall Line Coriolis
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Coriolis Effects
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Long-time Behavior of MCSs
Warm
L
H
Cool
(twice)
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Long-time Behavior of MCSs
Cool
H
Warm
L
H
Cool
(twice)
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Long-time Behavior of MCSs
Cool
zlt0
Z10 km
Warm
zgt0
Z5 km
zlt0
Cool
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Potential Vorticity
qlt0
Isentropes
Cool
Z10 km
Warm
qgt0
Z5 km
qlt0
Cool
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Davis and Weisman JAS 1994
Us 10 ms-1 over 2.5 km
T 3 h
T 6 h
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PV Z 2.1 km T 6 h
(Davis and Weisman JAS 1994)
Us 5
Us 15
Us 25
Us 20
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PV and Full Wind Us 10, Z 2.1 km
(Davis and Weisman JAS 1994)
T 3h, f
T 3h, f 0
T 6h, f 0
T 6h, f
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PV and Non-Divergent Wind Us 10, Z 2.1 km
(Davis and Weisman JAS 1994)
T 3h, f
T 3h, f 0
T 6h, f 0
T 6h, f
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PV and Irrotational Wind Us 10, Z 2.1 km
(Davis and Weisman JAS 1994)
T 3h, f 0
T 3h, f
T 6h, f
T 6h, f 0
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Wind Us 10, Z 9.8 km T 6h
(Davis and Weisman JAS 1994)
Non-divergent
Total
Irrotational
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Wind Us 10, Z .7 km T 6h
(Davis and Weisman JAS 1994)
Total
Non-divergent
Irrotational
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(Davis and Weisman JAS 1994)
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PV in 2-D Squall Line
Hertenstein and Schubert 1991, MWR
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dq/dt hHz/r, Hheating

Hzgt0
-
Hzgt0
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Long-time Behavior of MCSs
Cool
H
Warm
L
H
Cool
(twice)
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Summary MCV and associated PV generated by
unbalanced portion of flow (e.g., MCV cant be
produced properly within a balanced model) Flow
becomes more balanced over time as MCV
develops Once reasonably balanced (gt 6 h?), one
can begin to apply large scale thinking for
diagnosing vertical motion, etc. MCV will tend
to persist in environments with weak mid-level
shear, and especially if convection can be
periodically retriggered
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Upscale Growth of Convection
Chris Davis (NCAR/MMM)
Bow echoes
0540 UTC 10 June, 2003
MCV
0600 UTC 10 June, 2003
MCSs
11 June, 2003
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Precipitation Forecasts and MCVs Comparison of
the Weather Research and Forecast (WRF) model and
the NCEP Eta model
Eta gt 4 cm
X
21 h WRF forecast valid 2100 UTC 29 June

• Eta poorly predicts MCV subsequent rainfall in
  wrong place
• WRF has a much better prediction, related mostly
  to a better MCV prediction.

200 km
Maximum Reflectivity in Column (dBZ)
24 h Forecast from NCEP Eta
Radar Composite 2100 UTC 29 June
gt 5 cm
X
X
6 h Rainfall ending 00 Z 30 June
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MCV Example (23 June 2000)
1245 UTC Visible Satellite
MCV Vorticity Signature
1200 UTC Eta 500 mb Analysis
MCV Center
New storms near MCV center
1300 UTC 5-km MSL Profiler Winds
Convection along old MCS outflow
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Longevity of MCVs
(based on 40-km RUC-2 analyses during JJA 1999)
N43
N43
Davis et al. 2002, MWR
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(Davis and Weisman JAS 1994)