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Area forecast discussion
National Weather Service Des Moines Iowa
659 am CDT sun Jul 21 2019

..updated for 12z aviation discussion...

Discussion.../today through Saturday/
issued at 341 am CDT sun Jul 21 2019

Majority of the precipitation has ended across the area with the
exception of some ongoing showers/isolated storms across far
southern Iowa early this morning in an area of Theta-E advection
aloft. An mesoscale convective system across NE and another across South Dakota both associated with
weak upper level disturbances that will continue to move east-southeast today
and bring continuing chances for precipitation across the south half
of the area today into tonight. The cold front that moved through
much of the area Saturday will remain nearly stationary across the
southern portion of Iowa today and finally push south of the state
tonight as a secondary front moves through associated with the upper
level shortwave dropping through the Great Lakes/Iowa tonight. This
will bring dry conditions and much less humidity to the area for
Monday. Expect precipitation this morning to be mainly relegated to
the far south/southwest with additional redevelopment later this
afternoon/evening across the southern half to third of the forecast
area with the push of the secondary front and the stalled out
boundary. Severe storms will be limited instability due to cloud
cover and lingering precipitation. Deep layer shear will be
sufficient though, so cannot rule out a strong storm with gusty
winds the main threat. Otherwise locally heavy rainfall still
possible with pwats around 2 inches.

High amplitude ridging still expected to be in place across the
western/central US into Monday and Tuesday with northwest flow
pattern aloft. A large area of surface high pressure will build
across the region keeping dry conditions going through much of the
week with much cooler air in place. 850 mb temps remain around +12c
Monday through Wednesday so have highs below average into the mid to
upper 70s Monday and then moderating some into the low 80s for
Tuesday and Wednesday. The upper ridge breaks down into Thursday and
Friday with an upper level trough dropping through the northern
plains and into the Great Lakes region by late this week/next
weekend. This will send a cold front through the state and bring the
next chances for precipitation to the state Friday into Saturday.
Will see temperature moderate even further into the weekend with
highs pushing back into the mid to upper 80s across the area.


Aviation.../for the 12z tafs through 12z Monday morning/
issued at 658 am CDT sun Jul 21 2019

Any lingering MVFR conditions over northern Iowa early this
morning will improve into VFR by mid morning if not sooner.
Farther south, there could be some bkn025 ceilings with scattered
showers and storms at times through early evening. Both of these
have a higher likelihood at otm compared to dsm. As drier air and
high pressure builds over the region, all terminals will become
VFR no later than mid to late afternoon.


Dmx watches/warnings/advisories...

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