Hot and dry conditions persist today, then cooler over the weekend and next week. Heat Advisory in effect until 8 pm for the Valley, Delta, and foothills for Moderate to Major HeatRisk. Potential for light precipitation chances mid-week in the foothills and mountains, and increased northerly winds mid to late week, however confidence is low on exact details at the moment
Discussion
Skies remain clear across the region early this morning. The weak low off the northwest coast of California is slowly approaching and satellite imagery shows some mid and high clouds developing to its north and east over far Northern California up into Oregon. There has yet to be any appreciable response by the marine layer (profilers indicate the depth remains below 1k ft) and surface pressure gradients remain similar to yesterday. Current temperatures are mostly a little milder compared to 24 hours ago and are generally in the 70s to mid 80s across the Central Valley.
One last hot and dry day lies ahead with most of the Central Valley forecast to see highs of around 100-105 along with low humidity. Winds remain generally light except for some local late-day breezes which will pick up again this afternoon as stronger onshore gradients develop. Widespread Moderate to Major HeatRisk is expected in the valley and foothills, and the Heat Advisory remains in effect until 8 PM this evening.
Incidentally – today marks the two year anniversary of Sacramento’s hottest day where the high reached 116. It was a nearly week long long period of extreme heat across interior NorCal two years ago that resulted in several days of daily record highs, and all-time record highs in Sacramento and Stockton (tied with 115).
CAMS continue trend of keeping deep convection that develops later today east of the Sierra crest into Nevada, and north of the region. Dry weather and a gradual cool down is then expected over the weekend and into early next week as ridge weakens over the area. While high temperatures will still be above average, cooler overnight lows for most areas will limit HeatRisk to mostly the Minor category.
Extended Discussion (Tuesday through Friday)
Kicking off Tuesday, weak troughing keeps us on track for cooler, near to below normal temperatures, breezy late-day winds, and an overall increasing trend in relative humidities. These conditions stick around into mid-week, but with the added possibility of unsettled weather. Clusters and ensembles continue exhibiting uncertainty regarding the timing, strength, and position of an amplifying trough as it digs down toward the Great Basin around mid to late next week.
The NBM shows a 10-20% chance of mountain thunderstorms at the mid-week mark. Additionally, the NBM has been highlighting the potential for breezy to gusty north winds along the western Valley late next week.
NBM probabilities of max gusts greater than 30 mph are sitting around 30-50%. Whether these winds materialize and their degree of strength are heavily dependent on the low’s path, but we anticipate forecast confidence to increase over the next few days. In the meantime stay tuned and we hope you enjoy the cooler weather!