Areas affected…Parts of western Nebraska and northeast Colorado
Concerning…Severe Thunderstorm Watch 549…
Valid 012237Z – 020000Z
The severe weather threat for Severe Thunderstorm Watch 549
SUMMARY…Thunderstorms may continue to pose a risk for severe hail
and strong surface gusts across and perhaps just east of the watch
through 6-8 PM MDT. It is not certain that an additional severe
weather watch will be needed east of WW 549, but trends will
continue to be monitored for this possibility.
DISCUSSION…Thunderstorms have become scattered to numerous across
the high plains of western Nebraska and eastern Colorado, in the
presence of thermodynamic profiles characterized by steep lower/mid
tropospheric lapse rates and CAPE on the order of 1500 J/kg.
Easterly near surface flow beneath mid-level westerlies appears to
be contributing to at least modest unidirectional shear, supporting
a few splitting storms and isolated supercell structures.
Storm motions have been largely due to right and left moving
propagation with respect to the light (up to 10 kts) westerly
deep-layer ambient mean flow. A continued gradual, general eastward
advection of activity is possible, including into portions of
Sheridan, Garden, and Deuel counties of Nebraska (east of the
watch), through 00-02Z. However, a more stable/strongly capped
environment east of the High Plains seems likely to limit continuing
severe weather potential any farther to the east, particularly as
the boundary layer begins to stabilize further with the onset
diurnal cooling this evening.
…Please see www.spc.noaa.gov for graphic product…
LAT…LON 42480333 42480201 41940168 40850217 39160273 38820374
39200436 40320406 42480333