Severe Thunderstorm Watch 9:00 PM

Massac County, Illinois, United States

Last updated: 8:34 PM CDT  ·  Refresh
28°C
Feels like 32°
Partly Cloudy
▲ 34°  /  ▼ 19°
Wind
4 mph NNW
Humidity
83%
Dew Point
25°
Pressure
29.40 inHg
Visibility
10 mi
UV Index
0.0
Cloud Cover
57%
Sunrise
5:51 AM
Sunset
8:11 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Massac County is currently partly cloudy at 28°C. Dry conditions are expected through the next 24 hours. Atmospheric instability is elevated (CAPE up to 2166 J/kg) — isolated convective development possible. Sunrise: 5:51AM · Sunset: 8:11PM.

Alerts

Severe Thunderstorm Watch
Expires 9:00 PM
45 AQI · Good Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
28°
13%
9 PM
26°
16%
10 PM
25°
14%
11 PM
24°
14%
12 AM
23°
7%
1 AM
22°
3%
2 AM
22°
3%
3 AM
21°
3%
4 AM
21°
3%
5 AM
19°
3%
6 AM
19°
3%
7 AM
21°
3%
8 AM
22°
3%
9 AM
24°
3%
10 AM
25°
3%
11 AM
26°
3%
12 PM
26°
3%
1 PM
28°
3%
2 PM
28°
3%
3 PM
28°
3%
4 PM
28°
3%
5 PM
28°
3%
6 PM
27°
3%
7 PM
27°
3%
7-Day Forecast
Tonight
34° 19°
Mostly Clear.
Wed
29° 18°
Mostly Clear.
Thu
27° 16°
Mostly Clear.
Fri
24° 16°
Mostly Cloudy with a 44% chance of rain.
Sat
30° 18°
Mostly Cloudy with a 45% chance of rain.
Sun
33° 23°
Clear.
Mon
33° 23°
Clear.
TimeTempConditionsPrecipWindHumidity
Now 28° Partly Cloudy 13% 4 mph NNW 83%
9 PM 26° Partly Cloudy 16% 3 mph NNW 87%
10 PM 25° Partly Cloudy 14% 4 mph NNW 87%
11 PM 24° Mostly Clear 14% 5 mph N 86%
12 AM 23° Mostly Clear 7% 7 mph N 85%
1 AM 22° Clear 3% 7 mph N 86%
2 AM 22° Clear 3% 7 mph N 87%
3 AM 21° Clear 3% 6 mph N 89%
4 AM 21° Clear 3% 6 mph NNW 90%
5 AM 19° Clear 3% 6 mph NNW 90%
6 AM 19° Clear 3% 7 mph N 90%
7 AM 21° Clear 3% 7 mph N 87%
8 AM 22° Clear 3% 8 mph N 83%
9 AM 24° Clear 3% 8 mph N 78%
10 AM 25° Mostly Clear 3% 8 mph N 75%
11 AM 26° Partly Cloudy 3% 9 mph N 71%
12 PM 26° Partly Cloudy 3% 9 mph N 68%
1 PM 28° Partly Cloudy 3% 9 mph NNE 66%
2 PM 28° Partly Cloudy 3% 10 mph NNE 65%
3 PM 28° Partly Cloudy 3% 10 mph NNE 64%
4 PM 28° Partly Cloudy 3% 10 mph NNE 66%
5 PM 28° Partly Cloudy 3% 10 mph NNE 68%
6 PM 27° Mostly Clear 3% 9 mph NNE 71%
7 PM 27° Mostly Clear 3% 9 mph NNE 73%
15-Day Forecast
Today
7/21
Mostly Clear
14%
19°
34°
Wed
7/22
Mostly Clear
3%
18°
29°
Thu
7/23
Mostly Clear
3%
16°
27°
Fri
7/24
Mostly Cloudy
44%
16°
24°
Sat
7/25
Mostly Cloudy
45%
18°
30°
Sun
7/26
Clear
8%
23°
33°
Mon
7/27
Clear
17%
23°
33°
Tue
7/28
Clear
17%
20°
32°
Wed
7/29
Drizzle
44%
18°
29°
Thu
7/30
Drizzle
44%
16°
29°
Fri
7/31
Drizzle
51%
16°
29°
Sat
8/1
Drizzle
60%
18°
30°
Sun
8/2
Drizzle
60%
19°
31°
Mon
8/3
Drizzle
60%
20°
31°
Tue
8/4
Drizzle
60%
20°
31°
45
Good
U.S. Air Quality Index · Dominant: PM2.5
50 100 150 200

Air quality is satisfactory and poses little or no health risk.

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
Dominant
45 AQI 8.2 µg/m³
O3
Ground-level ozone
31 AQI 33 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Today 45 Good 31 45
Thu 26 Good 26 18
Fri 29 Good 29 7
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 Tue Jul 21, 23:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 50 60 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE2329 J/kg
MLCAPE1567 J/kg
MUCAPE2329 J/kg
SBCIN-103 J/kg
MLCIN0 J/kg
Lifted Index-3.4
Kinematics
0–6 km Shear40 kt
0–1 km Shear11 kt
Eff. Shear45 kt
0–1 km SRH-98
0–3 km SRH-105
Eff. SRH-105
Storm Motion274° @ 31 kt
0–1 km EHI-1.4
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index13.2
Thermo & Levels
PWAT1.78 in
0–3 km LR5.0 °C/km
700–500 LR5.5 °C/km
Total Totals42.8
LCL952 hPa
LFC855 hPa
EL143 hPa
Freezing Lvl17,503 ft