SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1120 AM CDT Sun Oct 18 2020
Valid 181630Z - 191200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
Organized severe thunderstorms are unlikely through tonight.
...Eastern Oklahoma/Ozarks to Lower Ohio Valley...
Recent surface analysis placed a cold front extending from central
Lower MI southwestward to a low over the TX Big Country. A broad
warm-air advection regime will be in place in the vicinity of this
front as it push gradually southward/southeastward amid persistent
southerly low-level flow. Instability will be limited but still
sufficient for occasional lightning strikes in the stronger embedded
convective elements. Highest thunderstorm coverage is anticipated
from southern MO/southern IL into northern AR this evening and
overnight as lift provided by the warm-air advection is augmented by
large-scale forcing attendant to a low-amplitude shortwave trough
moving into the mid MS Valley. Vertical shear is strong enough for a
few more robust updrafts, but the modest instability should temper
updraft strength and persistence, limiting the overall severe threat
and precluding the need to introduce any hail probabilities.
Easterly wave currently approaching the southeast FL coast will
contribute to widespread thunderstorms across central and southern
FL this afternoon. A relatively warm and moist air mass remains in
place over the FL Peninsula, promoting moderate instability and the
potential for a few stronger storms. Even so, lapse rates will
remain weak and vertical shear modest, resulting in a relatively
low-probability severe potential.