Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 242348
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
648 PM CDT Wed May 24 2017

.SHORT TERM.../Tonight through Thursday/
Issued at 353 PM CDT Wed May 24 2017

A few wrap around showers still lingering over the southeast
forecast area as an area of low pressure lifts through the Ohio
Valley. High pressure ridge is moving into western Iowa this
afternoon and this has led to clouds becoming less widespread and
ceiling heights rising. The clouds will continue to diminish
overnight from west to east and winds will become light. Fog
potential is the primary concern given the light winds and
clearing skies in addition to recent rainfall creating moist top
soil conditions. There is the potential for dense fog to develop
with the most favored locations along the I-35 corridor where the
wind will be the lightest for the most prolonged time.

Warm advection will commence on Thursday and mid level clouds will
increase during the afternoon in response. A few showers and
possibly isolated thunderstorms may develop west of the forecast
area by the afternoon. At this time, timing should keep this
activity just west through the afternoon. Temperatures will be
warmer and in the upper 60s to mid 70s.

.LONG TERM.../Thursday night through Wednesday/
Issued at 353 PM CDT Wed May 24 2017

Low potential for any significant weather to impact the forecast
area during the extended period. The GFS and ECMWF and even the
NAM/SREF have come into a little better agreement through early
Saturday before the discrepancies begin to show up again late in
the weekend into early next week. Utilized a blend through
Saturday and then continued to lean slightly more towards the GFS
Sunday into next week.

Thursday night into Saturday...weak shortwave cuts across Iowa
and looks to bring a few showers and thunderstorms late tomorrow
night through midday Friday. Surface high pressure builds into the
state Friday afternoon into early Saturday morning. Lowered pops
or went completely dry Saturday morning with a significant amount
of dry air below 650mb through 18z. Low confidence with any
significant measurable rain during this time with the amount of
dry air to contend with until better theta-e advection moves
across southern Iowa by the afternoon.

Sunday through Wednesday...large upper level low remains planted
over the Great Lakes and advects several shortwaves across the
region during this period. GFS has been a little more consistent
with the timing of shortwaves Sunday afternoon and again Monday
afternoon. Certainly confident to nudge cloud cover and winds
Sunday afternoon as mixing and surface pressure gradient
increases. Have chance pops going Sunday afternoon and again
Monday afternoon/evening with the aforementioned shortwaves.

&&

.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 648 PM CDT Wed May 24 2017

High pressure builds into the state so any remaining MVFr cigs
should go VFR by 02Z.  Surface winds light and variable the main
concern is for fog between the favored 09Z - 13Z timeframe.  At this
point I put MVFR vsbys in eastern TAF locations but may need to
expand to KDSM.  Overall not expecting much coverage or dense fog
but there will be an aviation impact to consider.

&&

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

&&

$$

SHORT TERM...Donavon
LONG TERM...Podrazik
AVIATION...FAB


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