Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 252334

Area Forecast Discussion
National Weather Service Des Moines IA
634 PM CDT Mon May 25 2020

...Updated Aviation Discussion...

.DISCUSSION.../Tonight through Monday/
Issued at 242 PM CDT Mon May 25 2020

Another day and another remnant MCV lifting north through Kansas
complicating the severe weather potential for this afternoon and
evening. Widespread showers and thunderstorms have developed over
southwest IA, eastern Kansas and much of Missouri this afternoon. A
few low topped storms are already rotating north of Lawrence and in
the northeast quad of the MCV. Splitting storms are also evident
near Kansas City which is sensible given the deep unidirectional
flow with some modest speed shear. This entire region of storms will
lift into southern and central Iowa over the next several hours and
maintain an isolated tornado or local wind damage potential. Any
tornado threat will likely be landspout in nature given the low
level stretching potential and lack of overall surface flow. CAM
solutions appear to be resolving the current MCV better than
yesterdays event and the currents storm`s anvils are not shadowing
upstream unstable regions which would promote stronger updrafts
reaching southern Iowa, unlike Sunday when anvils dropped
temperatures and instability ahead of approaching storms. Saturating
profiles and weakening mid-level lapse rates will lower the hail
threat today.

The rich Gulf moisture stream continues to feed into Iowa with PWATs
in excess of 1.5 inches will and keep the potential for locally
heavy rain. That said, like Sunday, storms will be progressive with
a break overnight. Expect a few locations to receive 2 to 3 inches
or rainfall but that is not forecast to be widespread. Therefore, no
Flash Flood Headlines at this time. The western trough will
transition into a upper low drifting south into the Southern Plains
into Wednesday before beginning to slowly shift east Thursday then
finally beginning to shear out with any remnant energy moving
quickly to the east. The Gulf of Mexico flow into Iowa will
continue into Thursday before the upper low pushes far enough east
to cut the flow from the state. The surface boundary will remain
over Iowa through this time and combined with repeated pushes of
theta-e advection and short wave fragments, will result in
periodic shower and thunderstorms chances. The severe weather
threat during this time will be low but a cumulative heavy rain
threat with river flooding or flash flooding becoming possible at
some point.

Little change to the extended as the well advertised Canadian High
arriving Friday with drier and less humid air and will feature high
temperatures into the upper 60s to mid 70s through Sunday.


.AVIATION.../For the 00Z TAFS through 00Z Tuesday evening/
Issued at 629 PM CDT Mon May 25 2020

Scattered convection to persist through 02-04z with periodic MVFR
to IFR visibility from the rain and ceilings. Then expecting IFR
ceilings overnight through at least 12z Tuesday. Additional
showers and storms are possible through the day tomorrow.


Issued at 235 PM CDT Mon May 25 2020

Numerous rounds of thunderstorms through Thursday may lead to a
cumulative heavy rainfall threat that could lead to rivers rising
and flowing out of their banks. At this time, the greatest
potential is over central and south central Iowa including the Des
Moines, Raccoon and Iowa Rivers and associated tributaries. Local
rainfall totals during this time of 3 to 5 inches are possible
with many locations receiving 1 to 2 inches.





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