Flash Flood Warning — Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA 7:45 PM

Delaware County, Pennsylvania, United States

Last updated: 7:22 PM CDT  ·  Refresh
23°C
Feels like 24°
Rain
▲ 29°  /  ▼ 21°
Wind
9 mph S
Humidity
94%
Dew Point
21°
Pressure
29.44 inHg
Visibility
10 mi
UV Index
0.0
Cloud Cover
95%
Sunrise
5:50 AM
Sunset
8:25 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Delaware County is currently rain at 23°C. Precipitation is likely — peak probability 74% around 9 PM. Atmospheric instability is elevated (CAPE up to 1075 J/kg) — isolated convective development possible. Sunrise: 5:50AM · Sunset: 8:25PM.

74 AQI · Moderate Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
23°
72%
9 PM
23°
73%
10 PM
23°
60%
11 PM
23°
61%
12 AM
23°
65%
1 AM
23°
46%
2 AM
22°
47%
3 AM
22°
47%
4 AM
22°
51%
5 AM
21°
50%
6 AM
22°
48%
7 AM
22°
36%
8 AM
23°
44%
9 AM
24°
41%
10 AM
26°
36%
11 AM
26°
33%
12 PM
26°
34%
1 PM
28°
28%
2 PM
28°
24%
3 PM
28°
26%
4 PM
28°
24%
5 PM
28°
24%
6 PM
27°
22%
7 PM
27°
22%
7-Day Forecast
Tonight
29° 21°
Rain, 72% chance.
Wed
30° 20°
Rain, 50% chance.
Thu
29° 18°
Mostly Clear.
Fri
29° 18°
Mostly Clear.
Sat
30° 18°
Partly Cloudy.
Sun
31° 18°
Rain, 62% chance.
Mon
32° 20°
Drizzle, 66% chance.
TimeTempConditionsPrecipWindHumidity
Now 23° Rain 72% 9 mph S 94%
9 PM 23° Rain 73% 8 mph SSW 93%
10 PM 23° Heavy Rain 60% 8 mph SSW 93%
11 PM 23° Rain 61% 8 mph SSW 94%
12 AM 23° Overcast 65% 9 mph SSW 93%
1 AM 23° Overcast 46% 10 mph SW 91%
2 AM 22° Mostly Cloudy 47% 9 mph SW 91%
3 AM 22° Mostly Cloudy 47% 9 mph SW 92%
4 AM 22° Mostly Cloudy 51% 8 mph SW 93%
5 AM 21° Mostly Cloudy 50% 8 mph SW 93%
6 AM 22° Partly Cloudy 48% 7 mph SW 90%
7 AM 22° Partly Cloudy 36% 8 mph SW 87%
8 AM 23° Rain 44% 9 mph WSW 82%
9 AM 24° Partly Cloudy 41% 9 mph WSW 75%
10 AM 26° Mostly Clear 36% 10 mph W 68%
11 AM 26° Mostly Clear 33% 10 mph W 64%
12 PM 26° Mostly Clear 34% 10 mph W 64%
1 PM 28° Mostly Clear 28% 10 mph W 65%
2 PM 28° Mostly Clear 24% 10 mph W 63%
3 PM 28° Mostly Clear 26% 9 mph W 60%
4 PM 28° Mostly Clear 24% 9 mph W 56%
5 PM 28° Mostly Clear 24% 9 mph W 54%
6 PM 27° Mostly Clear 22% 8 mph W 56%
7 PM 27° Mostly Clear 22% 7 mph W 58%
15-Day Forecast
Today
7/21
Rain
72%
21°
29°
Wed
7/22
Rain
50%
20°
30°
Thu
7/23
Mostly Clear
3%
18°
29°
Fri
7/24
Mostly Clear
3%
18°
29°
Sat
7/25
Partly Cloudy
7%
18°
30°
Sun
7/26
Rain
62%
18°
31°
Mon
7/27
Drizzle
66%
20°
32°
Tue
7/28
Drizzle
66%
20°
31°
Wed
7/29
Drizzle
54%
19°
30°
Thu
7/30
Drizzle
54%
19°
31°
Fri
7/31
Drizzle
60%
20°
30°
Sat
8/1
Drizzle
60%
20°
30°
Sun
8/2
Drizzle
60%
20°
31°
Mon
8/3
Drizzle
60%
21°
31°
Tue
8/4
Drizzle
90%
21°
32°
74
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
74 AQI 21.5 µg/m³
O3
Ground-level ozone
37 AQI 41 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Today 74 Moderate 37 74
Thu 54 Moderate 43 54
Fri 54 Moderate 49 54
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 70 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE373 J/kg
MLCAPE963 J/kg
MUCAPE1395 J/kg
SBCIN-297 J/kg
MLCIN0 J/kg
Lifted Index-2.3
Kinematics
0–6 km Shear40 kt
0–1 km Shear29 kt
Eff. Shear40 kt
0–1 km SRH197
0–3 km SRH154
Eff. SRH38
Storm Motion227° @ 37 kt
0–1 km EHI0.5
Composite Parameters
Sig. Tornado0.6
STP (eff)0.0
Supercell1.1
K-Index32.2
Thermo & Levels
PWAT2.00 in
0–3 km LR4.3 °C/km
700–500 LR6.3 °C/km
Total Totals47.1
LCL979 hPa
LFC688 hPa
EL270 hPa
Freezing Lvl13,911 ft