Western Heatwave is Immense!

Fig. 1: NOAA/NWS weather watch, warning, and advisory areas.

Discussion: High impact weather is primarily driven by excessive heat heading into the July 4^th Holiday Weekend (Fig. 1). An Excessive Heat Warning driven by extreme heat index has expanded in the Mid-south U.S. to include most of Arkansas, Northern Louisiana, and Northern Mississippi. An attendant Heat Advisory stretches from Texas to Georgia and parts of the Ohio Valley. The warning and advisory are valid through tomorrow.

In the West, an expanding heatwave has developed. Excessive Heat Warnings cover most of California. The warning is valid through the weekend. Heat Advisories are posted for San Francisco and Los Angeles coastal areas. An Excessive Heat Watch is posted for Phoenix, AZ, Reno, NV, and Eastern Washington where excessive heat is likely to develop.

Heavy rains from strong to severe thunderstorms have caused Flash Flood Warnings for rivers in Northern Missouri. River flooding in much of the Midwest U.S. is ongoing.

Severe thunderstorms featuring wind damage risk are forecast for the western Great Plains and along the Ohio River today (Fig. 2). Severe storms continue across the Missouri Valley tomorrow and may extend as far east as the Mid-Atlantic States (Fig. 3). Once again, tomorrow’s severe weather is mostly concerned with damaging wind gusts. Tornado risk is low. Heavy rain causing flooding extends across the Missouri Valley today (Fig. 4) and Upper Midwest tomorrow (Fig. 5). Excessive rainfall and flooding will appear in Southern Texas by Sunday associated with Beryl.

Fig. 2-3: NOAA/SPC severe weather outlook for the U.S. today and tomorrow.

Fig. 4-5: NOAA/WPC heavy rain/flood risk area forecast for today and tomorrow.

The U.S. population weight cooling degree day forecast maintains above normal electricity demand through mid-July with not much change from yesterday’s forecast (Fig. 6).

Fig. 6: The U.S. population weight CDD forecast utilizing all models, their consensus, and comparing with 24 hours ago and the 10-year/30-year normal.