Analyses of the 10 June and 19
June 2002 IHOP Convection
Initiation Cases
(with a minor plug for BLE!)
Yvette P. Richardson
Nettie R. Arnott
James N. Marquis
Brian Monahan
June 14, 2004
IHOP Scientific Workshop
Surface Analysis 1900 UTC
Overall Evolution
10 June 2002 IOR
Data Collection: 1918 UTC – 2118 UTC
CI: 2103 UTC
Sounding in IOR 2044 UTC
Dry air above
boundary layer
LCL
3 km AGL
Top of
domain
Weak capping
inversion
Sounding near CI 1935 UTC
LCL
3 km AGL
High Temporal Resolution Loop
King Air W vs. Radar W
King Air track = black line
3
7401230
m AGL
m AGL
Correlation
= 0.78
Correlation
= 0.83
2
Cold colors = -w
1
0
-1
-2
-3
Warm colors = +w
King
KingAir
Air
A
A
Radar
Radar
A’
A’
23.0 km
23. 5 km
100 m AGL
Warm colors =
convergence
Cold colors =
Divergence
Contoured every
2 x 10 –3 s-1
(0 contour not shown)
23.0 km
23. 5 km
100 m AGL
Warm colors =
convergence
Cold colors =
Divergence
Contoured every
2 x 10 –3 s-1
(0 contour not shown)
23.0 km
23. 5 km
100 m AGL
Warm colors =
convergence
Cold colors =
Divergence
Contoured every
2 x 10 –3 s-1
(0 contour not shown)
23.0 km
23. 5 km
100 m AGL
Warm colors =
convergence
Cold colors =
Divergence
Contoured every
2 x 10 –3 s-1
(0 contour not shown)
Parcel trajectory movies
Parcels reach 100 m AGL at 1953 UTC
Box =IOR
Height = 1.4 km
Parcels reach 100 m AGL at 2017 UTC
View Point: Ahead of the cold front looking
towards the North West
1955 UTC
1946 UTC
2007 UTC
2010 UTC
IOR convergence
beings weakening
2020 UTC
IOR convergence
beings weakening
2025 UTC
IOR convergence
beings weakening
2034 UTC
IOR convergence
beings weakening
2039 UTC
IOR convergence
beings weakening
2045 UTC
2037 UTC
IOR convergence
beings weakening
2055 UTC
2056 UTC
2143 UTC
Why was there no initiation of deep
convection within the IOR?
Potential Temperature at 600 m AGL
Behind cold front
Ahead of cold front
P3 Track
1956 UTC
1939 UTC
2018 UTC
2035 UTC
Mobile Mesonet Warming
Convection did not initiate in IOR
because…


Weakening temperature gradient across
cold front led to weaker frontal circulation
Dry air aloft made growth difficult to
sustain
2007 UTC
Weakening
convergence
2056 UTC
Why did convection initiate so
close by?




Enhanced convergence?
Cold front did not
dissipate?
Boundary – cold front
intersection? Hints of this
in satellite and radar data
Did wave pattern along
front have any influence?
Future Work




ELDORA data near CI (with Kingsmill)
Photogrammetry to map clouds
Submit paper for Special Issue
Data assimilation / Numerical modeling



Fill in data gaps
Influence of nearby developing convection
Influence of warming and convective
instability
June 19 CI Case

Dryline near Colby, KS
DOW2
DOW2
XPOL
IOR #1
IOR #2
XPOL
DOW3
DOW2
XPOL
DOW3
DOW2
Deployment #2 – 21:20+ UTC
25
13.5
14


Deployment B Loop 1
Deployment B Loop 2
Z=400m
Vorticity in Color
White contours of w
Strong misocyclones –
separated from w by
approximately ¼ wavelength
wmax
Z=400m
Vorticity in Color
White contours of w
Misocyclones similar
intensity to previous time
Updraft filling in along line
DZ
Initiation of Deep Convection
Cells apparent at 21:23 in DOW3
scans
Initiation captured by XPOL but
occurs ‘behind’ DOW3 while
DOW2 is in motion
Unclear if origin can be traced to
features within the IOR
DOW3 21:23
Aircraft may be needed to fill in
the gaps
Later Initiation

Deployment 2 Loop 3

Misocyclone Loop w/raw radar data
4pm CDT Dustdevil
6 pm CDT Landspout
Future Work




Combine wind analyses with water vapor
measurements (lidar, mobile mesonets,
dropsondes, satellite, MIPS, mobile
radiometer, etc.)
Perform trajectory calculations to look at
initiation and misocyclone
formation/evolution
Cloud Photogrammetry Analysis (with Erik
Rasmussen)
Submit Paper for Special Issue
Boundary Layer Evolution
(14 June 2002)

Fine Resolution Radar Loop from 13001900 UTC