SPC MD 1101

Sat, 04 Jul 2020 22:58:02 +0000 UTC

MD 1101 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST SOUTH DAKOTA AND THE SOUTH DAKOTA/WYOMING/NEBRASKA TRI-STATE AREA.

Mesoscale Discussion 1101
NWS Storm Prediction Center Norman OK
0557 PM CDT Sat Jul 04 2020

Areas affected...southwest South Dakota and the South
Dakota/Wyoming/Nebraska tri-state area.

Concerning...Severe potential...Watch unlikely 

Valid 042257Z - 050100Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms developing from southwest South Dakota into
eastern Wyoming will pose a risk for severe hail and wind over the
next 1-2 hours.

DISCUSSION...Thunderstorms developing along a trough axis across
southwest SD into far eastern WY have shown signs of strong updrafts
despite relatively weak deep layer shear (effective bulk wind shear
at around 20-30 knots) and weak forcing for ascent. These strong
updrafts are likely being supported by  MLCAPE on the order of
1000-1500 J/kg and steep mid-level lapse rates of 8-9 C/km on top of
a deep, well mixed boundary layer. These storms will briefly pose a
risk for severe hail with the stronger updraft pulses prior to
becoming outflow dominant or experiencing inhibiting storm
interactions from neighboring convection along the trough axis.
Steep low-level lapse rates associated with the well-mixed boundary
layer coupled with a dry 1-3 km sub-cloud layer will also support
the potential for severe wind gusts with any thunderstorm outflow.

..Moore.. 07/04/2020

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

ATTN...WFO...ABR...LBF...UNR...CYS...

LAT...LON   42630477 43150408 43540319 43870226 44240171 44130109
            43820102 43220156 42940216 42370383 41880455 41880507
            42240514 42630477