Hot and dry weather will continue this week with Major to Extreme HeatRisk persisting across much of the region. Elevated fire weather concerns will also continue.
Key Points
- Long-duration, dangerous heat event persists this week, though temperatures won’t be as extreme as this past weekend.
- Excessive Heat Warning is in effect for the northern half of the Sacramento Valley and foothills through 8 PM Friday.
- Heat Advisory is in effect for the Sierra, southern Cascades, and Burney Basin until 8 PM Friday.
Discussion
Skies remain clear across NorCal as the upper ridge adjusts to further east and south of the region compared to the weekend. This is allowing at least some relief to work its way inland as the Delta Breeze has increased as offshore surface gradient weakens. Current temperatures are running around 5-10 degrees cooler compared to 24 hours ago from the Delta into the southern Sacramento and northern San Joaquin Valleys. Elsewhere, readings are mostly similar to early Sunday.
Hot and dry weather will continue this week, though it won’t be quite as hot today and Tuesday as the ridge weakens a bit. The Excessive Heat Warning has been cancelled for the southern Sacramento Valley, Delta and northern San Joaquin Valley where temperatures will be 10-15 degrees lower compared to the weekend and HeatRisk has lowered into the Moderate category. Further inland, Major to locally Extreme HeatRisk will persist and Warnings/Advisories remain in effect.
By Wednesday, the ridge will strengthen and extend westward once again bringing renewed heat to the region through the end of the week with more widespread Major to Extreme HeatRisk and heat- related Warnings/Advisories may need to be reissued for the Delta, Sacramento and Stockton areas.
Extended Discussion (Friday through Monday)
Strong upper high over the Desert SW Friday with cutoff low off the CA coast. Low progged to slowly lift north over the weekend, then weaken to trough and progress Monday. Some models showing potential for afternoon isolated deep moist convection over the Sierra Nevada Friday/Saturday, although NBM keeping forecast dry for now.
Cooling trend expected with highs Friday in the Central Valley from 104 to 111 lowering to the mid 90s to 103 Sun/Mon. In the foothills and mountains, highs Friday forecast in the 90s to 105, lowering to the 80s and 90s Sun/Mon.