Day 1 Severe Weather Outlook

Valid 041200Z – 051200Z

…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST
NEBRASKA INTO SOUTHWEST SOUTH DAKOTA…

…SUMMARY…
Isolated thunderstorms could produce small to marginally severe hail
from northwest Nebraska into southern South Dakota this evening.

…Central Plains region…

A large area of continental-polar high pressure will advance through
the eastern states today. In wake of this feature a lee cyclone will
deepen over the central through northern High Plains in association
with an approaching shortwave trough. A plume of very steep (8-8.5
C/km) mid-level lapse rates will overspread the corridor of limited
moisture return (dewpoints generally in the upper 40s to low 50s F)
supporting 800-1200 J/kg MUCAPE. A cold front will accompany the
shortwave trough into the High Plains by late afternoon, but
surface-based initiation appears limited given likelihood of a
capping inversion. However, thunderstorms are expected to develop
during the evening from northwest NE into southwestern SD along and
ahead of the front within zone of strengthening low-level warm
advection and deeper forcing for ascent accompanying the shortwave
trough. These storms will likely be elevated above the stable
surface layer, but steep mid-level lapse rates, 1000 J/kg MUCAPE and
40-45 kt effective bulk shear will support potential for mid-level
updraft rotation and hail with some of the storms.

..Dial/Nauslar.. 10/04/2019

$$

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.