|Mesoscale Discussion 1443|
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Mesoscale Discussion 1443
NWS Storm Prediction Center Norman OK
0326 PM CDT Fri Jul 12 2019
Areas affected...southeast WY...far northeast CO and the NE
Concerning...Severe potential...Watch unlikely
Valid 122026Z - 122200Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated storms could produce hail and locally strong wind
gusts over the next few hours.
DISCUSSION...Thunderstorms have developed in easterly upslope flow
regime over higher terrain this afternoon. A quasi-stationary
surface boundary extended east/northeast from a surface low over
northeast CO into north-central NE, with a surface trough extending
north to south across eastern WY. This is resulting in confluent
flow over the region from far northeast CO into southeast WY and
western NE, where dewpoints ranged from the low 60s west to low 70s
east, except near higher terrain where dewpoints were in the 50s.
Atop this moist airmass, very steep lapse rates are in place atop a
weakening EML, and the boundary layer becomes increasingly unstable
with eastward extent into the richer boundary layer moisture. MLCAPE
quickly increases from around 1000 J/kg near I-25 to great than 2000
J/kg across western NE. As storms move off of higher terrain into
this reservoir of instability, modest effective shear (25-35 kt)
should be sufficient to maintain brief strong updrafts and organized
cells, the strongest of which will be capable of hail and locally
strong wind gusts. This initial threat should remain rather isolated
over the next 1-3 hours and a watch is not immediately necessary.
However, a greater threat could develop downstream across parts of
northern/central NE later this evening/tonight if organized
convection can develop/persist. This threat may need to be addressed
separately in the coming hours.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 41260570 41860587 42490593 42820566 42970500 42920391
42510309 41840267 40730257 40390288 40220343 40160418
40260474 40530545 41260570
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