Fort Dodge, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

959
FXUS63 KDMX 242344
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
644 PM CDT Thu Jul 24 2025

 ...Updated for the 00z Aviation Discussion...

.KEY MESSAGES...

- Showers and thunderstorms possible over far southern Iowa
  late this afternoon into the evening. Heavy rainfall is the
  primary concern, but gusty winds are also possible.

- Additional showers and storms expected late Friday into
  Saturday, mainly over southern into central Iowa. This
  rainfall could exacerbate conditions and lead to
  flooding/flash flooding in areas that saw heavy rain last
  night or tonight.

- Hot and humid conditions develop Sunday and Monday.

&&

.DISCUSSION...
Issued at 240 PM CDT Thu Jul 24 2025

Rainfall has all but subsided over the area early this afternoon,
although radar does indicate a few weak returns near the
Iowa/Missouri border. This area will be where additional
thunderstorm development is anticipated this afternoon and evening
as another weak wave orbits the broad upper ridging. This will bring
a stream of warm, moist south southwesterly flow upgliding over the
boundary in place over central to northern Missouri. As has been the
theme this year, these storms will exist in a moisture rich
environment, with an axis of 2.2 to 2.4 inch PWATs just to the south
of the state. This, in conjunction with mean storm motions roughly
parallel to the boundary, will bring prolonged heavy rainfall
starting late this afternoon into the evening. Model QPF shows
anywhere from 2 to 4 inches within the heaviest band and some
isolated pockets over 4 inches. placement of this heavier
rainfall axis will be primarily south of the state and into
Missouri, mainly impacting those in the far southern Iowa
counties along the Iowa/Missouri border. That said, models have
been less than reliable this year, so not ruling out a
regression to yesterday`s runs which had storms (and coincident
rainfall) slightly farther north into southern Iowa, especially
as the low level jet ramps up overnight. Fortunately, southern
Iowa didn`t see near the rainfall amounts from last nights
precipitation as those farther north, so this should help
mitigate hydrological impacts for at least tonight. Likewise,
the better instability axis also seems to be displaced to the
south with minimal deep layer shear in place. Therefore, the
overall severe threat appears low.

Any showers and thunderstorms still lingering tomorrow morning
should generally diminish as the LLJ diminishes into the morning
hours. However, another, slightly more prominent wave of energy will
lift northeastward into the state again tomorrow, pushing the
boundary farther north into the state. This will bring yet another
chance for both heavy rainfall and stronger storms into the forecast
area tomorrow afternoon through the overnight. From a moisture
perspective, the environment tomorrow night won`t be too
dissimilar from today/tonight, but may include a slightly
stronger moisture transport component. The key difference
between tonight and tomorrow lies with the 25 to 35 kt LLJ nosed
up into southern to south central Iowa, as opposed to a more
west to east orientation tonight. This will provide a steady
stream of moisture and forcing through the night, prolonging the
amount of time rain is falling, especially in far southern
Iowa. The main concern will be a cumulative effect of heavy rain
tonight which would be exacerbated by more heavy rainfall
tomorrow in areas where rain fell on both nights. Southern Iowa
would be the area most likely to see heavy rain both nights, but
is also the area with the driest soils relative to the rest of
the state. This should help raise the bar for flash flooding and
river flooding, but two nights of 2 to 4+ inch rainfall would
still likely create some issues, especially in areas that
achieve the higher end of that range on either night. Model
guidance is showing a signal for isolated pockets of 6 to 8
inches of total rainfall by Saturday morning, mostly over
northern Missouri and far southern Iowa.

Of similar concern, tomorrow`s rainfall will reach farther north
into the state than tonight`s, which poses a risk to areas that are
already experiencing elevated river levels from last night`s
rainfall in northern Iowa. As implied earlier, models have been
following a southerly trend, which is in the right direction to
avoid worsening conditions across the north, but still something to
keep an eye on. This is especially true in areas in central to north
central Iowa where water will be routing into and additional
rainfall is more of a possibility.

Finally, in addition to the heavy rainfall, not going to rule out
the potential for a few stronger storms on the nose of the low level
jet Friday night into Saturday. The storm prediction center
currently has the area in a general thunderstorm outlook with
minimal risk for severe weather, likely due to the lower CAPE values
and marginal deep layer shear. However, could certainly still see
some gusty winds overnight as any heavier cores collapse.

Friday night activity lingers into Saturday morning, then diminishes
through the day as an elevated mixed layer begins to leak in from
the west behind the wave. This will help to negate convection on
Saturday, although may see a few diurnally driven storms in the east
before those warmer 850 mb to 700 mb temperatures arrive aloft. This
elevated mixed layer (700 mb temperatures > 12C) remains overhead
Sunday into Monday, which will help to limit convective activity
through the end of the weekend and into early next week; bringing a
much needed break from the rain. Of course, this time of year you
trade one thing for another, as the warm temperatures aloft will
translate down to hot temperatures at the surface. Similarly, while
the atmosphere is capped off, our stream of surface moisture still
continues at the surface. This, in conjunction with moist soils and
corn evapotranspiration, will produce hot and humid conditions
Saturday and Sunday, pushing forecasted heat indices over 105F
areawide. Assuming this forecast remains on track tomorrow, heat
headlines will be needed for at least Sunday and Monday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 640 PM CDT Thu Jul 24 2025

MVFR cigs and shower/thunderstorms chances are the main forecast
highlights and that will be over mainly southern Iowa. Rain will
be at KOTM at times early in the period and there is chances for
thunderstorms there on Friday. Currently there is SCT/BKN cigs
in the 2.5/3.5 kft range across Iowa though mostly VFR to start
the period. There is an increased potential for MVFR cigs late
tonight and into parts of Friday. In addition monitoring fog
potential overnight and this would be most favored over northern
Iowa and at KFOD/KMCW if some clearing occurs. Light wind with
variable wind direction at times tonight becoming southeast on
Friday.

&&

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

&&

$$

DISCUSSION...Dodson
AVIATION...Donavon