132
FXUS63 KSGF 180515
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
1215 AM CDT Fri Sep 18 2026

.KEY MESSAGES...

- A Heat Advisory is in effect through Saturday. Highs near 100
  with Heat Index values 100-105 can be expected. Several daily
  records may be tied or broken.

- Isolated showers and storms this afternoon, particularly
  across the eastern Ozarks and south-central Missouri.

- Cooler conditions with scattered rain chances arrive early
  next week. Details on the exact extent of the cooldown and
  location of the highest rain chances remain uncertain at this
  time.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 101 PM CDT Thu Sep 17 2026

Synoptic and Mesoscale Overview:

Broad ridging continues to overspread the central and eastern
CONUS today, with a quasi-stationary front draped across
northern Missouri. Dew points are in the upper 60s to near 70
degrees as temperatures rise into the mid 90s.

Heat Advisory:

The combination of high temps and dew points will once again
produce afternoon heat index values between 100-105 degrees
today and tomorrow. With consecutive days of 100+ HI, we have
maintained the Heat Advisory areawide.

Isolated Storms Today and Tomorrow:

A fairly stagnant environment suggests persistence forecasting
will be a reliable method today. That is, isolated to widely
scattered convection looks to initiate across portions of
southeast and south-central Missouri this afternoon and evening
in response to diurnal heating and weak capping (~25 J/kg)
within a zone of weak forcing. Steep low-level lapse rates but
modest vertical totals suggest a few of the stronger pulse
storms will be capable of downburst winds of 50 to 60 mph, but
most if not all activity should remain sub-severe. In fact, most
CAMs are slightly less bullish in convective initiation today
than they were yesterday. Thus, PoPs have been limited to
20-25%.

By Friday, models show some slightly drier air creeping into far
southern Missouri. This drier air will confine the PoP footprint
to portions of central Missouri. Most areas will remain dry
otherwise.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 101 PM CDT Thu Sep 17 2026

Higher Rain Chances Late Saturday thru Monday:

Global models depict a broad mid-level shortwave finally
translating east through the Plains and into the Midwest
Saturday into Sunday. The latest suite of guidance has continued
its slower/later trend with the passage of the attendant
surface front through Missouri sometime late Saturday night into
Sunday. The increased lift and modest shear along this front
will aid in convective initiation likely in the form of loosely
organized clusters. The best rain chances will be across central
Missouri, with decreasing chances as you look south where drier
air will be present. Due to the slow nature of the front, rain
chances will persist through Monday afternoon, but all day
washouts are not expected.

NBM Probabilistic Rainfall (Sat Night thru Mon):
>0.10 inch: 50-70%
>0.25 inch: 40-60%
>1.00 inch: 10-30%

Heat through at Least Saturday:

There is medium to high confidence in continued afternoon heat
index values reaching near 100 deg through at least Saturday,
hence the Heat Advisory through 8 PM Saturday evening. If the
aforementioned cold front really slows down as it passes through
Missouri, or if convection/cloud cover is not quite as
widespread as global models suggest, then an extension of the
advisory may be needed across southern Missouri where
temperatures will remain abnormally hot. Confidence is not high
enough to make that decision at this point, however.

Cooler Conditions Early Next Week:

There is high confidence that cooler temperatures will arrive
next week. What is less certain is exactly how much cooler these
temperatures will end up being. Ensembles continue to disagree
in just how far the upper-level trough digs and how much the
ridge retreats; indeed, NBM temperature interquartile spreads
increase to 7-9 degrees by Monday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1211 AM CDT Fri Sep 18 2026

VFR conditions with mostly clear skies/afternoon fair-weather Cu
again today. Low chances for isolated pop-up thunderstorms again
today, especially across central and eastern Missouri. Light SSW
winds through the period, LGT/VAR at BBG.

&&

.CLIMATE...
Issued at 326 AM CDT Thu Sep 17 2026

Record High Temperatures:

September 17:
KSGF: 96/1953
KJLN: 95/1953
KVIH: 97/1953
KUNO: 97/1953

September 18:
KSGF: 95/2019
KJLN: 97/2022
KVIH: 95/1953
KUNO: 96/1972

September 19:
KSGF: 96/1954
KJLN: 99/2024
KUNO: 97/1954

September 20:
KSGF: 97/1954
KJLN: 99/1954
KVIH: 95/1954
KUNO: 97/1954

September 21:
KUNO: 95/1955


Record High Minimum Temperatures:

September 17:
KSGF: 73/1978

September 18:
KSGF: 74/1931

September 19:
KSGF: 73/1931

September 20:
KSGF: 74/2018

September 21:
KSGF: 73/1931

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory until 8 PM CDT Saturday for KSZ073-097-101.
MO...Heat Advisory until 8 PM CDT Saturday for MOZ055>058-066>071-
     077>083-088>098-101>106.

&&

$$

SHORT TERM...Didio
LONG TERM...Didio
AVIATION...Nelson
CLIMATE...Nelson