SPC MD 644


MD 0644 Image

Mesoscale Discussion 0644
NWS Storm Prediction Center Norman OK
0806 PM CDT Thu May 16 2019

Areas affected...Portions of Central Nebraska

Concerning...Severe potential...Watch possible 

Valid 170106Z - 170300Z

Probability of Watch Issuance...40 percent

SUMMARY...Ongoing storms in southwest Nebraska have shown some
marginally severe hail on MRMS MESH. Storms may be able to maintain
their intensity as the low-level jet increases during the evening.
However, uncertainty with regard to the storm coverage and intensity
lessen confidence in WW issuance. Trends will be monitored.

DISCUSSION...A few storms are ongoing in southwest Nebraska.
Observed 00Z soundings from LBF and OAX show mid-level lapse rates
near 9 C/km, though deep-layer shear remains modest at around 40 kts
in the west to near 30 kts in the east. The steep mid-level lapse
rates should drive a hail threat even as these storms become more
elevated with time. As the low-level jet increases this evening and
mid-level heights weakly fall, at least some of these storms may
maintain their intensity. However, there is uncertainty with regard
to how much new development will occur on the nose of the jet and,
with the jet core progged to be farther east of the current
activity, how intense the current storms will be in an hour or two.
Consequently, CAM guidance differs widely on the exact evolution of
this scenario. These factors reduce confidence in the need for a WW,
though trends will continue to be monitored over the next few hours.

..Wendt/Guyer.. 05/17/2019

...Please see www.spc.noaa.gov for graphic product...


LAT...LON   41370250 42020151 42499949 42419812 41799726 41089761
            40519898 40209994 40240078 40360153 40670198 41370250 

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