490
AWUS01 KWNH 311937
FFGMPD
MNZ000-IAZ000-NEZ000-SDZ000-010130-

Mesoscale Precipitation Discussion 0360
NWS Weather Prediction Center College Park MD
336 PM EDT Fri May 31 2024

Areas affected...Northeastern Nebraska through Southwest Minnesota

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

Valid 311936Z - 010130Z

SUMMARY...Multiple forcing mechanisms causing widely scattered
storms capable of producing up to 3 inch per hour rainfall rates.
Flash flooding possible in flood-sensitive areas.

DISCUSSION...Moisture advecting northwestward at the nose of a low
level jet originating in the Gulf is colliding with a surface cold
front, mid-level deformation zone, and upper level shortwave over
Nebraska to result in an area of very slow moving storms that have
a history of producing rainfall rates to 3 inches per hour. The
area has some sensitivity to flooding with soil moisture levels at
or a little above average for this time of year. FFGs in much of
the highlighted region are below 2 inches in an hour and 2.5
inches in 3 hours. PWATS are above 1.5 inches in most of the
region and SPC Mesoanalysis shows max surface based cape as high
as 2,000 J/kg over western Iowa.

Steering flow in the vicinity of the front is weak due to the
presence of the mid-level deformation. The area of rain with
embedded slow moving convection is expected to expand upscale into
a more well defined boundary, with convection developing and
riding northeast along it. The congealing of multiple areas of
storms may result in steadier rainfall, but the peak rainfall
rates of in embedded convection may decline a bit as a result.

Flash flooding will be possible in any areas where the storms are
slow moving or localized areas of training convection develop. The
upper level shortwave moving across the area will serve as the
"back edge" of the convection, shifting everything north and east
and weakening with time with loss of solar heating after 00Z.

Wegman

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

ATTN...WFO...DMX...FSD...GID...LBF...MPX...OAX...

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

LAT...LON   44559553 44549447 43669420 42399501 41199700
            40469800 41539885 42709832 43899707 44549554