Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 252338
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
633 PM CDT Mon Mar 25 2019

.DISCUSSION.../Tonight through Monday/
Issued at 318 PM CDT Mon Mar 25 2019

Ridge of high pressure will continue to move southeast and pass
across Iowa overnight. Ahead of the system, the clouds have been
gradually diminishing with drier air moving into the state. The
clouds that have been stubborn across central Iowa have become more
cellular through the day. These clouds may linger into the evening.
Very dry air has moved into northeast Iowa with dew points in the
teens and even single digits. These dew points have come back up a
bit this afternoon.  Biggest concern is what temperatures will do
with high pressure arriving tonight and low dew points in place. At
this time, it appears these low dew points will remain out of the
forecast area. Expect overnight lows in the mid 20s to mid 30s.

Warm advection will move back into the region on Tuesday as the area
of high pressure moves east of the state. The high will stall a bit
during the day though and will limit the amount of warm advection.
High temperatures on Tuesday will be in the low to mid 50s. The area
of high pressure pushes quickly east Tuesday night and Wednesday
with strong warm advection arriving. The thermal ridge will move
into the area by late Wednesday with 850 mb temperatures pushing
above 10C over western Iowa. Profiles will not mix overly deep
Wednesday to around 900-875 mb with an inversion above that level.
Still the gusty south winds and the potential for near surface super
adiabatic lapse rates should push temperatures into the 60s all
locations with a few sites near 70.

A large upper low moving southeast towards Hudson Bay will squash
the upper ridge and will move a cold front into the region by
Thursday. This boundary will oscillate over the region into Friday
before a short wave moving through the southern stream moves to the
south and drags it through by Saturday. A few periods of showers and
thunderstorms are possible during this period, especially over
southern Iowa. Will need to monitor for precipitation amounts and
potential impacts on area streams. Still a fair amount of
uncertainty of the boundary movement. In addition, a few chances for
light snow on the north side of the boundary, mainly northern Iowa
late Thursday night/Friday and over much of the area as the boundary
drops south Friday night.

The weekend looks mostly dry and cool with highs in the upper 30s to
upper 40s with overnight lows dropping into the 20s Saturday night.

&&

.AVIATION.../For the 00Z TAFS through 00Z Tuesday evening/
Issued at 633 PM CDT Mon Mar 25 2019

Mainly low VFR with patchy MVFR through 06Z then cigs becoming a sct
deck.  Sfc wind will be lgt and vrb becoming southerly around 10kts.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

DISCUSSION...Donavon
AVIATION...FAB


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