Residents across the San Francisco Bay Area should brace themselves for another period of warmer temperatures and a slight chance for dry lightning, according to the latest reports from the National Weather Service (NWS). These conditions are expected through early August, bringing moderate HeatRisk to inland valleys and elevated terrains. The potential for dry lightning, triggered by monsoonal moisture, poses a significant threat to wildfires, especially given the hot and dry conditions. The National Weather Service emphasized, "Dry lightning can start fires and impact outdoor activities! When thunder roars, go indoors! See a flash, dash inside!" NWS Bay Area backed this warning with a video illustrating the moisture increase and potential storm cells.
The NWS San Francisco office underlined that while the chance for thunderstorms on Friday and Saturday remains low, the potential impact is significant due to the high likelihood that any rain from these storms will evaporate before reaching the surface. Furthermore, the average temperature in July was already the hottest on record for much of the Bay Area, creating a precarious backdrop for potential lightning-induced wildfires. Wildfires often start when lightning strikes without rain, underscoring the high risks associated with the current weather patterns. Details of the forecast were posted by the National Weather Service.
Addressing the short-term outlook, the NWS mentioned early signs of the moisture plume in southern and central California, which has already caused lightning strikes and flooding in those regions. "Currently beginning to see signs of the moisture plume moving into southern and central CA this morning," stated the National Weather Service in their forecast discussion. As the moisture moves northward, it'll encounter dry air layers, making precipitation unlikely. However, prospects of thundershowers, particularly in eastern areas, increase come 5 PM, but with low probabilities for meaningful rain to reach the parched ground.
Looking ahead, temperatures will continue to hover at approximately 5 degrees above normal into next week. This enduring heat, coupled with increased cloud cover from the incoming moisture, could exacerbate the pre-existing moderate HeatRisk. The NWS forecast indicated that areas in the interior East Bay, South Bay, and interior Central Coast will begin to see moderate HeatRisk by early next week. They also projected a decrease in dry lightning threats by midday Saturday, providing a brief respite from the ongoing fire dangers. Mariners, too, should expect to face challenging conditions, with moderate breezes and sea heights, potentially intensifying due to Tropical Storm Carlotta that looms in the Eastern Pacific.
Aviation operators also feel the impact of weather anomalies, with IFR-LIFR ceilings in certain areas and fluctuations in stratus development that affect flight schedules. The NWS has advised a cautious approach, with breezy onshore flow developing, very low confidence of virga, and scattered thundershowers passing through the region from south to north through the afternoon and evening. The aviation sector will be vigilant as the conditions unfold over the next few days.
