Areas Affected: Coachella Valley - San Diego County Deserts - San Gorgonio Pass Near Banning
This Notice Updated: Tue, 10/6 12:33pm
Updated: Tue, 10/6 2:33pm
Urgency: Expected
Next Update: Fri, 10/9 8:00pm
Severity: Severe
Certainty: Likely
Details:
* WHAT...Dangerously hot conditions with high temperatures as high as 108 on Thursday possible. Nights will be quite warm with low temperatures in the mid 70s to lower 80s. * WHERE...Coachella Valley, San Diego County Deserts, and San Gorgonio Pass near Banning. * WHEN...From 10 AM Wednesday to 8 PM PDT Friday. * IMPACTS...Heat related illnesses increase significantly during extreme heat events.
Information:
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
Take extra precautions when outside. Wear lightweight and loose
fitting clothing. Try to limit strenuous activities to early morning
or evening. Take action when you see symptoms of heat exhaustion and
heat stroke.
Temperatures will decrease Wednesday by a few degrees for the coast and valleys. Highs will range from the 70s and 80s in the mountains, upper 80s to lower 90s at the coast, mid 90s to lower 100s in the valleys, lower to mid 90s in the High Desert, and mid 100s in the lower desert.
Data Courtesy of San Diego Weather Forecast Office
Evaporative Cooler Effectiveness by City
Thousand Palms
Outside Temp104°F
Dew Point55°F
Est. Output79°F
Updated: Oct 6, 2:46 PM PDT
Palm Desert (Hwy 111 & El Paseo)
Outside Temp103°F
Dew Point57°F
Est. Output80°F
Updated: Oct 6, 2:44 PM PDT
Palm Springs Airport
Outside Temp103°F
Dew Point46°F
Est. Output75°F
Updated: Oct 6, 1:53 PM PDT
Thermal Airport
Outside Temp102°F
Dew Point54°F
Est. Output78°F
Updated: Oct 6, 1:52 PM PDT
How to Read This
Score
0–100, based on the wet-bulb depression — how much cooler the air could get versus the actual outside temperature. Drier air means more room to cool, so a bigger gap scores higher.
Wet-Bulb Depression
The gap between the outside (dry-bulb) temperature and the wet-bulb temperature — the coolest evaporation alone could get the air. A bigger gap means drier air and more room for the cooler to work with.
Estimated(Est.) Output
The approximate temperature of the air coming out of the cooler, estimated by cooling the outside temperature most of the way toward the wet-bulb temperature.
Efficiency
These numbers assume 80% saturation efficiency — typical for a well-maintained direct (single-stage) evaporative cooler.
Lower dew point + higher temp = better cooling
(This guide generally will work for misting systems also)
EXTREME HEAT WARNING 
