Heat Advisory — Boone, MO, Moniteau, MO, Cole, MO, Osage, MO, Callaway, MO, Montgomery, MO, Gasconade, MO, Warren, MO, St. Charles, MO, Franklin, MO, St. Louis, MO, St. Louis City, MO, Jefferson, MO, Crawford, MO, Washington, MO, St. Francois, MO, Ste. Genevieve, MO, Iron, MO, Madison, MO, Reynolds, MO 7:00 PM

Saint Charles County, Missouri, United States

Last updated: 3:50 AM CDT  ·  Refresh
24°C
Feels like 29°
Mostly Cloudy
▲ 33°  /  ▼ 22°
Wind
3 mph W
Humidity
90%
Dew Point
23°
Pressure
29.36 inHg
Visibility
10 mi
UV Index
0.0
Cloud Cover
83%
Sunrise
5:53 AM
Sunset
8:24 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Saint Charles County is currently mostly cloudy at 25°C. Precipitation is likely — peak probability 74% around 6 PM. Atmospheric instability is elevated (CAPE up to 2242 J/kg) — isolated convective development possible. Sunrise: 5:53AM · Sunset: 8:24PM.

Alerts

Heat Advisory
Boone, MO, Moniteau, MO, Cole, MO, Osage, MO, Callaway, MO, Montgomery, MO, Gasconade, MO, Warren, MO, St. Charles, MO, Franklin, MO, St. Louis, MO, St. Louis City, MO, Jefferson, MO, Crawford, MO, Washington, MO, St. Francois, MO, Ste. Genevieve, MO, Iron, MO, Madison, MO, Reynolds, MO
Expires 7:00 PM
54 AQI · Moderate Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
24°
8%
4 AM
24°
15%
5 AM
23°
17%
6 AM
23°
17%
7 AM
24°
33%
8 AM
26°
48%
9 AM
29°
54%
10 AM
30°
55%
11 AM
31°
55%
12 PM
32°
56%
1 PM
32°
63%
2 PM
32°
64%
3 PM
32°
64%
4 PM
32°
57%
5 PM
31°
66%
6 PM
30°
73%
7 PM
29°
63%
8 PM
28°
59%
9 PM
26°
49%
10 PM
26°
39%
11 PM
25°
35%
12 AM
25°
23%
1 AM
24°
16%
2 AM
24°
16%
7-Day Forecast
Today
33° 22°
Heavy Rain, 73% chance.
Mon
36° 22°
Mostly Clear.
Tue
37° 20°
Partly Cloudy.
Wed
28° 18°
Clear.
Thu
28° 17°
Clear.
Fri
29° 17°
Rain, 82% chance.
Sat
31° 16°
Drizzle, 63% chance.
TimeTempConditionsPrecipWindHumidity
Now 24° Mostly Cloudy 8% 3 mph W 90%
4 AM 24° Mostly Cloudy 15% 3 mph W 91%
5 AM 23° Partly Cloudy 17% 3 mph W 91%
6 AM 23° Mostly Clear 17% 2 mph WNW 90%
7 AM 24° Mostly Clear 33% 3 mph NW 86%
8 AM 26° Mostly Clear 48% 3 mph NNW 82%
9 AM 29° Clear 54% 3 mph N 77%
10 AM 30° Mostly Clear 55% 3 mph N 73%
11 AM 31° Mostly Clear 55% 4 mph N 70%
12 PM 32° Partly Cloudy 56% 5 mph N 67%
1 PM 32° Mostly Cloudy 63% 6 mph NNE 69%
2 PM 32° Mostly Cloudy 64% 6 mph NNE 71%
3 PM 32° Rain 64% 7 mph NE 73%
4 PM 32° Rain 57% 7 mph NE 75%
5 PM 31° Rain 66% 7 mph ENE 77%
6 PM 30° Heavy Rain 73% 6 mph E 79%
7 PM 29° Mostly Cloudy 63% 6 mph E 82%
8 PM 28° Partly Cloudy 59% 6 mph E 86%
9 PM 26° Partly Cloudy 49% 6 mph E 89%
10 PM 26° Partly Cloudy 39% 6 mph E 90%
11 PM 25° Partly Cloudy 35% 5 mph E 91%
12 AM 25° Partly Cloudy 23% 5 mph ESE 91%
1 AM 24° Partly Cloudy 16% 5 mph ESE 92%
2 AM 24° Partly Cloudy 16% 5 mph ESE 92%
15-Day Forecast
Today
7/19
Heavy Rain
73%
22°
33°
Mon
7/20
Mostly Clear
7%
22°
36°
Tue
7/21
Partly Cloudy
19%
20°
37°
Wed
7/22
Clear
8%
18°
28°
Thu
7/23
Clear
16%
17°
28°
Fri
7/24
Rain
82%
17°
29°
Sat
7/25
Drizzle
63%
16°
31°
Sun
7/26
Clear
18%
18°
34°
Mon
7/27
Drizzle
44%
19°
37°
Tue
7/28
Clear
44%
23°
37°
Wed
7/29
Rain
90%
21°
34°
Thu
7/30
Drizzle
60%
21°
35°
Fri
7/31
Drizzle
60%
22°
36°
Sat
8/1
Drizzle
60%
22°
36°
Sun
8/2
Clear
60%
21°
35°
54
Moderate
U.S. Air Quality Index · Dominant: PM2.5
50 100 150 200

Air quality is acceptable. Unusually sensitive people should consider limiting prolonged outdoor exertion.

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
Dominant
54 AQI 10.7 µg/m³
O3
Ground-level ozone
26 AQI 28 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Today 54 Moderate 26 54
Mon 76 Moderate 40 76
Tue 121 Unhealthy for Sensitive Groups 39 121
About the Air Quality Index
0–50 Good
51–100 Moderate
101–150 Unhealthy for Sensitive Groups
151–200 Unhealthy
201–300 Very Unhealthy
301–500 Hazardous

The U.S. AQI runs 0–500. The overall value equals the highest individual pollutant sub-index, and the dominant pollutant is the one driving it. PM2.5 (fine particles) is reported in µg/m³ and ozone (O3) in ppb. Forecast source: NWS NAQFC.

1000850700500400300250200150100 -40-30-20-10010203040 0.41247101624 LCLLFCEL0°C Temperature (°C) Pressure (hPa)
Temp Dewpoint Parcel (SB) CAPE CIN Dry adiabat Moist adiabat Mixing ratio
RAP
Valid Sun Jul 19, 07:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE1023 J/kg
MLCAPE1008 J/kg
MUCAPE1117 J/kg
SBCIN-97 J/kg
MLCIN0 J/kg
Lifted Index-3.0
Kinematics
0–6 km Shear10 kt
0–1 km Shear12 kt
Eff. Shear11 kt
0–1 km SRH-16
0–3 km SRH-28
Eff. SRH-28
Storm Motion281° @ 21 kt
0–1 km EHI-0.1
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index38.2
Thermo & Levels
PWAT2.19 in
0–3 km LR5.1 °C/km
700–500 LR5.4 °C/km
Total Totals45.5
LCL970 hPa
LFC799 hPa
EL199 hPa
Freezing Lvl16,066 ft