Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 312315

Area Forecast Discussion
National Weather Service Des Moines IA
615 PM CDT Tue Mar 31 2020

.DISCUSSION.../Tonight through Tuesday/
Issued at 346 PM CDT Tue Mar 31 2020

The primary concern will be one, higher confidence appreciable
precipitation event later in the work week. Short wave ridging and
warm advection on tap for tomorrow will transition to the passage
of a long wave trough through the northern Plains driving a
frontal passage with appreciable temp changes and precip. This
will quickly be followed by a transition to more progressive,
zonal flow early in the weekend and then very warm, southwest flow
ahead of the next long wave trough passage to end the period.

This evening a moisture starved MO Valley short wave is
attempting to generate some light precip across northern IA,
mainly driven by mid level kinematic forcing, but much of it
should remain virga. However later 1-3km thermodynamic forcing,
with warm/theta-e advection and frontogenesis, will follow with the
aforementioned ridging and produce a brief period for showers
north early in the morning leading into a warm day with widespread
60s+ for highs.

The 1-3km thermodynamic forcing will continue to build further
into Wed Night and Thursday ahead of the approaching long wave
trough very gradually increasing strength of coverage of warm
advection precip. By Friday forcing will deepen and eventually be
aided by more than patchy mid level kinematic lift which will also
be coincident with strong SSW-NNE frontogenesis boosting PoPs
into likely plus along and just behind the surface frontal
passage. Temps will cool sharply and would not be surprised to see
at least a mix of light snow northwest before the precip ends
heading into the weekend.

Ridging into Saturday will dry things about for a bit, but
southwest flow will turn more active into early next week with
broad-brushed low confidence PoPs and much warmer temps as IA
fully returns to the warm sector, including the potential for
widespread 70s for highs.


.AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/
Issued at 615 PM CDT Tue Mar 31 2020

Few if any concerns this period. Warm front drifting east will
enhance mid level cloud deck aft 06z across the area. Possible
shra or iso thunder west at KFOD/KDSM but some uncertainty remains.
Otherwise, VFR cigs and gradual shift to SE winds 12G20kt aft
11z. /rev




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