official data
Extreme heat still on the board from Death Valley to Phoenix — Bay Area and Mid-South under advisories
Official NWS Extreme Heat Warnings remain up across southern Nevada, southeast California deserts, and much of southwest Arizona on September 10, with Heat Advisories still covering the Bay Area/Central Valley and parts of Arkansas–Mississippi–Tennessee — while WPC’s HeatRisk map is the live seven-day impact panel.
Key facts
- CAP stamp
- ~21 active Extreme Heat Warning / Heat Advisory features at Desk fetch morning 10 Sep 2026 ET
- NWS Las Vegas EHW
- 10 AM–8 PM PDT/MST 10 Sep — highs 112–116°F Death Valley & Colorado River Valley; 105–110°F Las Vegas / Moapa / Pahrump valleys
- NWS Phoenix EHW
- Phoenix metro 105–109°F / Major Heat Risk through 8 PM MST 10 Sep; broader SW AZ / Imperial / Colorado River segments 105–115°F, some through 8 PM Fri 11 Sep
- NWS San Diego EHW
- Coachella / San Diego County deserts / San Gorgonio Pass through 8 PM PDT Friday 11 Sep
- Bay Area / Central Valley HA
- SF Bay Area / Central Coast through 10 PM PDT 10 Sep — temps 10–20°F above normal; Sacramento/Hanford valleys highs ~97–103°F
- Mid-South HA
- Little Rock / Memphis 11 AM–8 PM CDT 10 Sep — heat index up to ~109°F (AR) / ~107°F (E AR / N MS / W TN incl. Memphis)
- HeatRisk
- WPC experimental categories 0–4 — see live HUD at wpc.ncep.noaa.gov/heatrisk/; Desk does not invent static Magenta polygons
- Rolled off
- Sep 8 Central Plains EHW corridor largely off live CAP at fetch — not re-shipped as current
Late-season heat that still forces Extreme Heat Warning language over Death Valley, the Colorado River Valley, and Phoenix is the instrument-panel story — not a lifestyle “hot weekend.”
Desk reading of NWS CAP / WPC HeatRisk
Note
September 10’s official heat board is still red in the desert West. NWS has Extreme Heat Warnings up where the thermometer itself is the hazard — 112–116°F in Death Valley and the Colorado River Valley, 105–110°F across Las Vegas and Phoenix metro language, with some Arizona and Imperial Valley warnings carrying into Friday. California’s Bay Area and Central Valley sit under Heat Advisories into Thursday evening with temperatures 10–20 degrees above normal. Farther east, Little Rock and Memphis keep heat-index advisories near 107–109°F. WPC’s HeatRisk map is the seven-day companion panel — check it live; Desk is not painting invented Magenta polygons from memory.
Attribution: National Weather Service active CAP alerts via api.weather.gov (Extreme Heat Warning / Heat Advisory), offices including Las Vegas, Phoenix, San Diego, San Francisco, Sacramento, Hanford, Little Rock, Memphis — valid windows 10–11 Sep 2026. Supplementary: NWS/WPC HeatRisk. Watchers 8–10 Sep pieces were intake seeds only — not primary numbers.
Why it matters
Extreme Heat Warnings over Death Valley–Phoenix keep the desert West in the red column; Bay Area/Central Valley 10–20°F anomalies mean nights that do not cool; Mid-South heat-index advisories keep the humidity blade on the same national heat day. Live footprints after this CAP stamp = see live HUD.
Sources
Official data. Live values go to the HUD / source product.