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Surface Plot, 00 UTC 11 April 1997
(Shading: blue=dewpoints > 45; green=dewpoints
> 60)
The image above (click to get full
sized version) shows positions of major controlling synoptic
features at time of thunderstorm formation.
Note the strong warm front, which remained
stationary for most of the afternoon. The dryline (shown as brown
scalloped line) had pulled out of New Mexico in early afternoon
and dewpoints east of the dryline and south of the warm front
had risen to the mid/upper 50's and lower 60's in the southeasterly
flow in the region bounded by the warm front, dry line, Interstate
20 and the eastern portion of the Texas Panhandle.
Storms that formed north of the warm frontal
boundary formed in sheared flow and had strong mesocylones BUT
were outflow dominated at the surface. This is common for storms
that develop north of warm fronts where tremendous directional
and speed shear is evident, but proper phasing of outflow features
with warm inflow cannot occur.
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