Colorado Mesoscale Discussion

Areas affected…portions of western/central NE…northeast CO and
northwest KS

Concerning…Severe potential…Watch likely

Valid 111928Z – 112100Z

Probability of Watch Issuance…80 percent

SUMMARY…The severe threat will continue to increase from northeast
CO into southwest and central NE and far northwest KS. A watch will
likely be needed by 21z.

DISCUSSION…Early day cloud cover across parts of western NE and
northeast CO has eroded and temperatures are quickly climbing into
the 70s to near 80 F early this afternoon. Further east, where
strong heating has occurred, temperatures were in the mid to upper
80s. Surface dew points increase from the low 60s to the mid/upper
60s west to east from southwest NE/northeast CO eastward toward
central NE/KS. This is resulting in rapid destabilization, with
MLCAPE now ranging from 1000-2500 J/kg. Isolated CU is forming
across the area in response, and guidance has consistently indicated
storm initiation by 21z. This may be a little ambitious due to
stronger capping associated with earlier cloud cover, but certainly
expect storms in the 21-23z time frame.

Strong vertical wind profiles will be supportive of supercells and
steep midlevel lapse rates will favor large hail, some possible
larger than 2 inches in diameter. Region VWP data also shows backed
low level flow through about 2 km, resulting in curved low level
hodographs. As storms move into deeper moisture across NE/KS this
could result in a couple of tornadoes, especially across southwest
into central NE where a surface boundary will further increase 0-1
km SRH. During the evening, a southerly low level jet will increase
and storms may grow upscale into one or more bowing clusters. Trends
will continue to be monitored and a watch will likely be needed by

..Leitman/Hart.. 09/11/2019

…Please see for graphic product…


LAT…LON 40260336 41380299 41960271 42340199 42550088 42540017
42389951 42109922 41659905 41099920 40289968 39500042
39200119 39120184 39120260 39300317 39660340 40260336

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