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
from SPC Mesoscale Discussions https://bit.ly/1iTHpNe
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