Weather Update: Tuesday, November 21, 2017 (7:00 a.m.)
SAN DIEGO (NEWS 8/CNS) - San Diego County was lucky enough this year to avoid devastating, deadly wildfires like the ones that ripped through Northern California and have in the past wreaked havoc here, but the region is still facing late-season wildfire danger due to dry conditions, a potentially record-setting heat wave and unseasonable Santa Ana winds, authorities said Tuesday.
The National Weather Service predicts high temperatures on Wednesday and Thursday will be 15 to 25 degrees above average, and with Thanksgiving approaching, the county has seen no measurable rain for the first time in nearly four decades.
"It is increasingly likely that San Diego will fail to record measurable rainfall in November for the first time since 1980," the agency said.
On top of the hot, dry conditions that are expected this week -- and on the heels of the record-breaking heat wave that parched vegetation in October - - the United States Forest Service is also forecasting Santa Ana winds Wednesday that could drive a late-season wildfire. The Forest Service's Santa Ana Wildfire Threat Index, which categorizes Santa Ana winds based on anticipated fire potential, says that given existing conditions, "upon ignition, fires may grow rapidly."
"Easterly winds of 15 to 25 mph along with higher gusts can be expected across the San Diego Mountains," according to the threat index. "Humidity will be in the single digits. Fuels are very dry and will support high rates of spread should an ignition occur."
While the Santa Ana-driven wildfire threat will be only marginal on Wednesday, there is little precedent for Santa Ana fire potential this late into November. The deadly and destructive fires that overwhelmed San Diego County in 2003 and 2007 started in late October and were mostly contained by early November.
Temperatures will peak Wednesday, then drop slightly for Thanksgiving Day in most areas, the NWS said. [See table below for forecasted temperatures and records.]
Following the heat wave, temperatures are expected to cool a bit by next weekend.