999
FXUS63 KSGF 221140
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
640 AM CDT Fri Aug 22 2025

.KEY MESSAGES...

- Near average temperatures and mostly dry for the rest of this
  week, with highs in the upper 80s to low 90s.

- Below average temperatures to start next week, with 50-75%
  confidence for highs in the 70s to lower 80s.

- 20 to 50% rain chances will occur at times early next week
  with the highest chances occurring over southwestern Missouri
  where a 40-60% chance for more widespread above normal
  precipitation exists.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 300 AM CDT Fri Aug 22 2025

Current water vapor imagery depicts a broad swath of very dry
mid- and upper-level air stretching from southwest TX, up
through the Ozarks, and eastward to the Virginias. Our 00Z
sounding depicts this dry air quite well above the mixed layer,
with mid-level relative humidity at a meager 19%. This belt of
dry air is found along a nearly E-W oriented trough axis
stretching from the Ozarks to NJ. This trough is impinging on
the eastern edge of a broad mid- and upper-level high over the
western CONUS. North of the high is a dynamic trough and jet
streak digging into the Dakotas. The dynamic forcing is helping
to develop a strong cold front at the surface--also currently
over the Dakotas. These will be the main players for a cooldown
forecast for next week.


Near average temperatures for the rest of this week:

Ahead of the slowly digging trough aloft and surface cold front,
a shortwave ridge axis cutting through Missouri will continue to
keep temperatures near normal through Saturday. Highs today and
Saturday are expected to be in the upper 80s to lower 90s, with
lows tonight in the lower to middle 60s. Due to clear skies
during the night, radiational cooling may be enough to develop
some patchy fog--especially in low-lying areas and river
valleys--though dry air should limit coverage and density of
any fog.


Very low chances (<15%) for some isolated showers Saturday:

The aforementioned trough aloft and surface cold front will
start dropping south through the area Saturday afternoon and
into the overnight hours. Short-range models suggest there may
be enough moisture and convergence ahead of the front for some
isolated showers to occur northwest of I-44, especially if the
front takes on a quicker progression like modeled by the
NAM/NSSL. If this occurs, daytime heating may result in some
showers. If the frontal passage takes a later progression as
modeled by the HRRR/ARW/RAP, only some sprinkles could occur
during Saturday evening. Due to the uncertainty in timing of the
frontal passage coinciding with daytime heating, chances for
rain along the front are generally less than 15% northwest of
I-44.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 300 AM CDT Fri Aug 22 2025

Below average temperatures to start next week:

Once the aforementioned strong trough and cold front push
through the area, a stubborn longwave pattern will set up with
deep troughing over the eastern CONUS and a dynamic
northwesterly jet stream overtop Missouri. The deep troughing
will reinforce the strong cold front, allowing cooler than
average temperatures to settle into the area. After a transition
day on Sunday with highs in the lower 80s across central MO, and
in the upper 80s across southern MO, temperatures will drop into
the middle 70s to lower 80s for much of next week. Lows will
follow suit, being in the middle 50s to lower 60s, with
potential for upper 40s to lower 50s Tuesday night.

The temperatures outlined above are given by the NBM
deterministic forecast. It is important to note, however, that
during this period, NBM temperatures spreads are still quite
high due to slight variations in trough shape, orientation, and
intensity as depicted in cluster analysis. 25th-75th percentile
NBM spreads range from the upper 60s to the middle 80s for the
period. Either way the pendulum swings, there is a good chance
for below normal temperatures, with the CPC forecasts showing a
70-80% chance. 88 F is normal for late August, so even the 75th
percentile in the lower 80s would classify as below normal. If
the 25th percentile verified, we would be up to 15 degrees below
normal! Indeed, ensembles are pointing to this potential, with
the ECMWF Extreme Forecast Index showing values at 0.6-0.7 for
low maximum temperatures, and ESATs showing forecast 850 mb
temperatures at 10-14 C, which is <2.5th percentile for late
August.


20-50% chances for more widespread rainfall next week:

Within the longwave pattern with the dynamic northwesterly jet
stream, global deterministic models depict several jet streaks
and shortwaves progressing through the longwave. The wind speeds
in these jet streaks are being marked by ESATs as >99.5th
percentile for late August. Below normal August moisture will
act like above normal late-fall moisture with the well above
normal jet dynamics in place. In other words, synoptic ascent
in the right entrance region of each strong jet streak will make
good use of even the below normal moisture in place, leading to
chances for rain next week (generally 20-50% each day Monday
through Friday). Since the lift will mainly be synoptic ascent,
rain would likely be in the form of widespread
showery/stratiform precipitation. This is backed up by models
depicting near zero instability across the region. This means
there is potential for more widespread rain leading to more
widespread areas receiving decent rainfall totals, as opposed to
scattered thunderstorms leading to some areas seeing high
amounts and others seeing little to no rain.

With all that being said, there`s still quite a bit of details
to iron out. Since there are still ensemble differences in
trough shape, orientation, and intensity, there are differences
in the location of the axis of heaviest rainfall. Specifically
for Tuesday, ensemble QPF clusters have 74% of models with a
WNW-ESE oriented band of 1-2 inches of rain somewhere across
our CWA, and 26% keeping our area dry. Global model trends have
consistently moved this axis southward. Therefore, at the
moment, the highest chances for accumulating rainfall is across
the southwestern corner of Missouri and the extreme southeastern
corner of Kansas. In this area, the CPC has a 40-60% chance of
above normal precipitation. Of course, this also means a 33%
chance of near normal precipitation, and a 7-27% chance for
below normal precipitation. Trends will continue to be
monitored.

After Tuesday, the model spread increases significantly in where
and when chances of rain occur. This continues to result in
less confident rain chances each day (20-50%). That being said,
anywhere that does see rain, may see a more widespread/prolonged
behavior. The WPC continues to put a Slight Risk for heavy rain
across the southwest corner of Missouri and southeast corner of
Kansas for the dates of August 25th-30th.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 640 AM CDT Fri Aug 22 2025

VFR conditions to prevail for the entire TAF period at all
sites. Light 3-8 kt winds will oscillate between easterly and
north-northeasterly through the period. A 4-5 kft cu field will
be present between 16-01Z.


&&

.SGF WATCHES/WARNINGS/ADVISORIES...
KS...None.
MO...None.

&&

$$

SHORT TERM...Price
LONG TERM...Price
AVIATION...Price