Mesoscale Precipitation Discussion 0913
NWS Weather Prediction Center College Park MD
959 PM EDT Mon Oct 01 2018
Areas affected...Northern Illinois...Far Southeast
Wisconsin...Southwest Michigan
Concerning...Heavy rainfall...Flash flooding possible
Valid 020158Z - 020728Z
Summary...Rainfall amounts of 1 to locally 3 inches will be
possible across northern Illinois into southwest Michigan through
08z. Given some urban sensitive areas and potential for training
storms, flash flooding may be possible.
Discussion...Recent IR imagery continues to pockets of cloud top
cooling within the line of showers and storms across far southern
Wisconsin, eastern Iowa, and into northern Illinois. The heaviest
rainfall is beginning to push into northern Illinois in and around
the Rockford vicinity.
Precipitation is being fueled ahead of a strong 700 mb trough
along with favorable 850 mb moisture transport overrunning a warm
front that was analyzed right through the Chicago metro area into
southern Michigan. The most recent SPC mesoanalysis page shows
around 1000 J/kg of MUCAPE along/ahead of the precipitation well
within above normal PWATs of around 1.5 inches.
With unidirectional flow expected over the next several hours,
training convection will be possible across northern IL into
southwest MI. As this moves over sensitive urban areas from
Chicago northward to the Wisconsin border, intense rainfall rates
of 1 to locally 1.5 inches/hour will be possible. As a result,
localized flash flooding will be possible.
Taylor
ATTN...WFO...DVN...GRR...IWX...LOT...MKX...
ATTN...RFC...NCRFC...
LAT...LON 43018627 42758477 41888510 41668788 41658996
42448975 42838855 42908770
Last Updated: 959 PM EDT Mon Oct 01 2018