Mesoscale Precipitation Discussion 0726
NWS Weather Prediction Center College Park MD
157 AM EDT Tue Aug 28 2018

Areas affected...Southeast MN across WI

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

Valid 280556Z - 280956Z

Summary...Heavy thunderstorms along a line stretching across
Wisconsin from southeast Minnesota will persist early this
morning.

Discussion...KARX and KMCX radars are depicting heavy rainfall in
a swath from the MN/IA border all the way across WI with storm
total rainfall of 6 inches in western WI. Though this swath of
thunderstorms has broadened, it is being fed by a 55kt
southwesterly low level jet with a remnant cold pool to the north
maintaining a stationary and allowing repeating convection. One
hour rain rates are still 1.5 inches per hour as of time of
issuance.

Unfortunately there are ingredients to maintain this line in place
for several more hours. Instability is riding in with the low
level jet; generally 1500 J/kg per the RAP  analysis though the
RAP forecast has this increasing through 10Z. That jet is ahead of
the next shortwave which is centered over ND with the warm
conveyor belt stretching back to the SD/MN border per GOES-16
upper water vapor imagery. As of now it appears this line will be
unwavered over Wisconsin. Local rainfall of 10 inches are possible.

Jackson

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

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

LAT...LON   44309014 44288826 44158729 43098768 43019021
            43179225 44099240