Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 240445

Area Forecast Discussion
National Weather Service Des Moines IA
1145 PM CDT Mon Apr 23 2018

.SHORT TERM.../Tonight through Tuesday/
Issued at 255 PM CDT Mon Apr 23 2018

Confidence: Medium to High

Upper level low continues to pull away from our area with only a few
mid to high level clouds still present over southern Iowa. Plenty of
sunshine and a nice response today regarding mid day temperatures
despite little if any mixing across the region.  Tonight will remain
quiet with weak ridge of high pressure settling over the region and
eventually dissipating at the sfc as next system approaches.  Most
of Tuesday looks rather pleasant again with a general increase in
clouds during the late morning to afternoon hours. Highs across the
south...especially...will be mild again with H850 temperatures still
ranging from 7-8C during the afternoon hours.  A brief window of
increased mixing in the afternoon may help promote highs in the
lower 70s over the south again...with cooler afternoon highs over
the north due to cloud cover and colder H850 temperatures behind
a weak cold front dropping south into the region tomorrow. Highs
tomorrow north will likely be in the upper 50s/lower 60s compared
todays readings in the 60s.

.LONG TERM.../Tuesday night through Monday/
Issued at 255 PM CDT Mon Apr 23 2018

Confidence:  Medium to High

With the blocking ridge aloft in place and slow moving closed low
over the Southeast States...tomorrows system has little choice but
to drift south/southeast with time. This has been advertised for a
while and expecting again little more than chance light rain over
the south/southwest tomorrow evening/night as the system tracks away
from the region. Along with the cool front passing south of the area
temperatures aloft will cool to slightly below zero at H850 for late
tomorrow and Wednesday morning prior to eventual warming again into
the weekend. This will result in slightly cooler highs for Wednesday
afternoon with north northeast flow aloft. By Thursday another weak
boundary will move through the region. Models differ on impacts with
the Euro having a more moisture starved solution compared to the
GFS. In either case the Gulf is shut off from any moisture. For now
will continue with blended solution though given the pattern and
predominant ridge aloft...the rain is likely to be rather sparse and
of little impact.  Highs Thursday should moderate ahead of the front
with highs in the mid to upper 60s for the central and south and
only slightly cooler in the 50s over the north. The weekend will see
renewed warming with adiabatic compression across the Northern
Plains resulting in warming H850 temperatures from Friday through
Sunday.  Some uncertainty remains with regard to the approaching
system late in the weekend with a typical spread in solutions:  The
Euro is slower while the GFS brings the system into the region
already by Monday afternoon while the Euro later Monday night. Its
likely that much of the region will be in the 60s to lower 70s again
already by Saturday with Sun/Mon seeing highs generally in the 70s.
Sun/Monday H850 temperatures range from 10-15C/13-16C respectively.
Depending on cloud cover and mixing next Monday...some potential to
crack the 80 degree mark over the west/southwest.  Will wait and see
how trends compare over the next several days. With slower Euro
solution there would be a better chance of seeing the warmer high


.AVIATION.../For the 06Z TAFS through 06Z Tuesday night/
Issued at 1145 PM CDT Mon Apr 23 2018

VFR conditions will prevail for the next 24 hours.




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