Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 160436
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1136 PM CDT Fri Mar 15 2024

 ...Updated for the 06z Aviation Discussion...

.KEY MESSAGES...

- Becoming breezy to windy Saturday. Elevated Fire Danger.
- Colder Sunday and Monday then warming mid week.

&&

.DISCUSSION...
Issued at 210 PM CDT Fri Mar 15 2024

An overall quiet weather day across Iowa with high pressure centered
to the west over Nebraska and outside of some shallow cumulus
development (see Aviation section below) there is not much in the
way of weather this afternoon. Of particular interest today is the
strong PV anomaly/short wave cluster currently diving southeast
through Alberta and Saskatchewan. An initial boundary will pass
through late tonight into Saturday morning. This boundary will
mainly bring cold advection to the 925-850 mb range and will promote
good mixing and bring gusty northwest winds to the state. This
mixing will off set any weak surface cold advection that will be
ongoing during the daytime. The main energy associated with this
system will pass to the northeast of Iowa and this system will pass
through with a dearth of moisture. This system may be able to
squeeze out sprinkles in some areas but even that may be a stretch.
The stronger surface cold advection will be arriving late in the day
over northern Iowa and for the remainder of the area Saturday night.

Plan to stay the course and highlight elevated fire danger
conditions for Saturday. Many of the parameters are much more
marginal than previous higher end fire weather days this year. Still
expecting the gusty winds but the wind will be more 15 to 25 mph
with a few gusts to 35 mph. Potential for some cloud cover will
impact minimum relative humidity values that should stay more in the
25 to 35 percent range. Finally recent rain will leave at least some
residual moisture in near surface fuels though the dry tall grasses
will still burn easily. Bottom line, it is recommended to refrain
from burning Saturday.

Saturday night will not be too cold as mixing prevents temperatures
from bottoming out with lows mainly in the 20s. The upper level
thermal trough arrives Sunday into Sunday night and will be centered
over Iowa at 12z Monday. The thermal trough will shift east during
the day Monday with weak warm advection starting as the surface wind
turns more westerly. Still suspect the NBM temperatures are
suffering from warm bias correction for highs Sunday and Monday.
Sunday will certainly feel cold with brisk northwest winds. High
temperatures each day will be in the 30s to low 40s. The upper level
flow transitions to northwesterly on Tuesday then will become
more zonal/westerly Wednesday and Thursday and temperatures will
rebound back into the 50s and 60s. Chances for precipitation
return by Thursday as a strong short wave passes just south of
the state. The end of the week is become more noisy with the
handling of another strong upper level short wave moving into
the Pacific Northwest and how quickly that system may eject
westward. At this point, that system should not impact Iowa
through the extended period which is through next Friday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1136 PM CDT Fri Mar 15 2024

VFR conditions will prevail through the TAF period. Low level
wind shear expected to develop within the next couple hours and
continue through Saturday morning at all sites. The southwest
winds tonight will shift to out of the northwest by mid to late
morning across all sites with gusts of 25-30 kts expected at all
sites into the afternoon. Winds will begin to diminish by
Saturday evening.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Donavon
AVIATION...Hagenhoff


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