339
AWUS01 KWNH 051733
FFGMPD
WIZ000-052302-

Mesoscale Precipitation Discussion 0564
NWS Weather Prediction Center College Park MD
132 PM EDT Fri Jul 05 2024

Areas affected...Northeast WI

Concerning...Heavy rainfall...Flash flooding possible

Valid 051732Z - 052302Z

Summary...Locally significant flash flooding is underway across
portions of Waupaca County in northeast Wisconsin. Additional slow
moving cells with 2-2.5"/hr rainfall rates will likely lead to
additional instances of isolated flash flooding through the
afternoon, some of which could be significant.

Discussion...Radar and IR imagery continue to track an area of low
topped and efficient showers and thunderstorms beneath a
vertically stacked low center. Earlier, a small but slow moving
groups of cells over Manawa, WI with 2-3"/hr rain rates exhibited
backbuilding and produced an estimated 5-6" of rain, prompting
numerous water rescues and a Flash Flood Emergency for the town.
While that cluster has since moved east, additional cellular
development downstream of the initial activity was producing
1.5-2"/hr rainfall rates and elevated CREST Streamflow responses
east of Manawa.

This uptick in activity likely remains tied to increased forcing
for ascent as a well-defined vorticity max rounds the base of the
larger closed low, in the presence of focused frontal convergence
and strong surface heating. Recent mesoanalysis estimates show
upwards of 1000 J/kg of MUCAPE (oriented in a skinny profile with
.1 NCAPE) and 1.3" PWATS (above the 75th percentile) in the
vicinity of the convection. Combined with 5-10 kts of steering
flow beneath the close low, efficient slow moving cells are likely
to continue through this afternoon with 2-2.5"/hr rainfall rates
possible per recent HREF guidance.

Through this afternoon, localized rainfall amounts of 2-4" remain
possible where these clusters reside the longest. This will likely
lead to additional isolated instances of flash flooding as 1 HR
FFGs are quite low in the region in light of recent heavy rainfall
(.75-1"/hr). Additional localized significant flash flooding over
more vulnerable urban areas including Green Bay can not be ruled
out.

Asherman

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...ARX...GRB...MKX...

ATTN...RFC...NCRFC...NWC...

LAT...LON   45258878 44868781 44268761 43768782 43578824
            43758957 44239008 44878988