MD 1809 CONCERNING SEVERE THUNDERSTORM WATCH 539… FOR WESTERN AND CENTRAL WISCONSIN
Mesoscale Discussion 1809
NWS Storm Prediction Center Norman OK
0948 PM CDT Tue Sep 20 2022
Areas affected...Western and Central Wisconsin
Concerning...Severe Thunderstorm Watch 539...
Valid 210248Z - 210415Z
The severe weather threat for Severe Thunderstorm Watch 539
continues.
SUMMARY...A small cluster of intense thunderstorms will persist for
another few hours over western and central WI. Large hail is the
main threat, although the potential for locally damaging wind gusts
may be increasing. A downstream watch is unlikely, but not out of
the question.
DISCUSSION...A cluster of multiple supercells is affecting parts of
Pierce and Dunn counties of western WI. These storms are moving
southeastward at around 30 knots, and are slightly behind a surface
cold front progressing across the area. The southwestern-most storm
has a history of intermittent large to very large hail over the past
60-90 minutes. Given the post-frontal nature of the storms and
increasing cinh with loss of daytime heating, it appears likely that
the storms will weaken as they track into central WI during the next
few hours. However, a weak baroclinic zone extends across this area
with surface dewpoints in the mid-upper 60s. If the storms can grow
upscale and congeal into a more organized bowing line (as shown by a
few 00z CAMs), the potential for severe threat continuing east of WW
539 would increase - and a downstream watch would then need to be
considered. At this time that scenario seems unlikely.
..Hart.. 09/21/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GRB...MKX...ARX...MPX...
LAT...LON 45169233 45319080 44978964 44308907 43658897 43208966
43489124 44089243 44639260 45169233
