Maryland Heights, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

535
FXUS63 KLSX 231025
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
525 AM CDT Mon Jun 23 2025

.KEY MESSAGES...

- High temperatures will exceed 90 degrees in portions of the area through
  at least Thursday.

- There is a slight chance (20 - 30%) for showers and thunderstorms
  each day this week. The Heat Advisory has not been extended due
  to uncertainty on how this will impact the temperature forecast
  later this week.


&&

.SHORT TERM...  (Through Late Tuesday Afternoon)
Issued at 242 AM CDT Mon Jun 23 2025

Today and tomorrow will be characterized by more dangerous heat for
the majority of the area. Isolated showers and thunderstorms are
forecast today with scattered convection in the forecast for
tomorrow. Locations that do experience this can expect a small drop
in afternoon temperatures, but it won`t be enough to disrupt the
overall heat. The larger impact to temperatures will be in northeast
Missouri and west-central Illinois on Tuesday when cloud cover and
possibly precipitation from a cold front blow into these areas. I
lowered temperatures in these areas to accommodate this. I also
factored in persistence, as the flow has been relatively
unchanged over the past two days. Otherwise, lows fall into the
70s each day.

Jaja

&&

.LONG TERM...  (Tuesday Night through Sunday)
Issued at 242 AM CDT Mon Jun 23 2025

The stagnant mid-level ridge responsible for this heatwave will
continue to spin over the Ohio Valley through Wednesday before
degrading sometime on Thursday. This translates to at least a few
extra days of the dangerous heat, but to what extent is somewhat
uncertain. Confidence is very high (90%+) in air temperatures
exceeding 90 degrees Wednesday and Thursday. However, there is
reasonable spread in the NBM interquartile range concerning the
exact magnitude. This is important because if temperatures fall
closer to the 25th percentile (93/94 degrees), an extension of the
Heat Advisory becomes uncertain. If they fall closer to the 75th
(98/99 degrees) the extension will be necessary. In recent days,
observed temperatures have failed to reach the upper 90s under full
insolation, with KSTL only reaching 96 degrees on our hottest day.
In the coming days, there will be scattered to broken diurnal
cumulus, the potential for showers and thunderstorms each day, and
no significant low-level warm air advection. Putting these factors
together, I doubt we will see 75th percentile temperatures verify.
Despite this, these days will still be hot. However, confidence in
the heat reaching Heat Advisory criteria is still too low to warrant
an extension during this forecast package.

Jaja

&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 519 AM CDT Mon Jun 23 2025

VFR conditions will continue through the TAF period. There is a
slight chance of isolated showers and thunderstorms this
afternoon. The potential of impacts at any terminals from
convection is too low to mention in the TAFs. If a site does see a
thunderstorm, brief gusty and variable winds will be the primary
impact.

Jaja

&&

.CLIMATE...
Issued at 1225 PM CDT Thu Jun 19 2025

Record maximum temperatures at St. Louis, MO (STL), Columbia, MO (COU),
and Quincy, IL (UIN) along with the year of the record:

    |    6/23    |    6/24    |    6/25
-------------------------------------------------------
STL | 101 (1930) | 102 (1988) | 103 (2024)
    |            |            |
COU | 100 (1988) | 103 (1988) | 102 (1988)
    |            |            |
UIN | 100 (1934) |  99 (1988) | 102 (1931)


Record high minimum temperatures at St. Louis, MO (STL), Columbia, MO (COU),
and Quincy, IL (UIN) along with the year of the record:

    |    6/23    |    6/24    |    6/25
------------------------------------------------------
STL | 80 (2010)  | 80 (1914)  | 82 (1988)
    |            |            |
COU | 76 (2010)  | 77 (1937)  | 77 (1988)
    |            |            |
UIN | 80 (1944)  | 79 (1931)  | 80 (1937)


&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory until 9 PM CDT Tuesday for Audrain MO-Boone MO-
     Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-
     Iron MO-Knox MO-Lewis MO-Lincoln MO-Madison MO-Marion MO-
     Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls
     MO-Reynolds MO-Saint Francois MO-Sainte Genevieve MO-Shelby
     MO-Warren MO-Washington MO.

     Extreme Heat Warning until 9 PM CDT Tuesday for Jefferson MO-
     Saint Charles MO-Saint Louis City MO-Saint Louis MO.

IL...Heat Advisory until 9 PM CDT Tuesday for Adams IL-Bond IL-Brown
     IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL-Macoupin IL-
     Marion IL-Montgomery IL-Pike IL-Randolph IL-Washington IL.

     Extreme Heat Warning until 9 PM CDT Tuesday for Jersey IL-
     Madison IL-Monroe IL-Saint Clair IL.

&&

$$

WFO LSX