![\"\"](\"http:\/\/us.weatheramerica.com\/wp-content\/uploads\/sites\/2\/2025\/07\/san-bernardino-california-1707.jpg\")
<\/p>\n<\/p>\n
San Bernardino Mountains, California \u2014 Thursday, July 17, 2025, 9:00 AM EDT<\/strong><\/p>\n The first monsoonal thunderstorms of the season<\/strong> are expected to develop across Southern California’s mountain regions<\/strong> starting today<\/strong>, Thursday<\/strong>, and continuing through Saturday<\/strong>, with the San Bernardino Mountains<\/strong> seeing the greatest risk for storm activity<\/strong>, according to the National Weather Service<\/strong>.<\/p>\n As of this morning, forecast models<\/strong> indicate a 15% to 25% chance<\/strong> of thunderstorms forming over the San Bernardino Mountains<\/strong> this afternoon. Storms will be isolated<\/strong>, mostly driven by monsoonal moisture<\/strong> surging in from the southeast<\/strong>.<\/p>\n Friday, July 18<\/strong>, remains the day with the highest forecast confidence<\/strong> for thunderstorm development<\/strong>, with a 40% to 50% likelihood<\/strong> of convective activity<\/strong> across the mountain ridges<\/strong>, particularly in the San Bernardino range<\/strong>. These storms could linger<\/strong>, moving slowly due to weak upper-level winds<\/strong>, which could lead to localized flooding<\/strong>.<\/p>\n According to a National Weather Service bulletin<\/strong> released on July 14<\/strong>, some of these slow-moving storms<\/strong> may produce brief downpours<\/strong>, although most will remain confined to elevated terrain<\/strong> and are not expected to impact lower-elevation cities<\/strong>.<\/p>\n By Saturday, July 19<\/strong>, the chance of thunderstorms<\/strong> falls to 30% to 40%<\/strong>, with activity remaining mostly scattered and elevation-bound<\/strong>. Sunday<\/strong> sees a sharp decrease<\/strong> in storm risk, with only a 5% to 15% chance<\/strong> of development over the highlands.<\/p>\n In adjacent desert communities like Hesperia<\/strong> and Victorville<\/strong>, daytime highs<\/strong> are projected to reach the low to mid-90s \u00b0F<\/strong> (32\u201335 \u00b0C<\/strong>), with overnight lows<\/strong> dropping into the mid-60s \u00b0F<\/strong> (17\u201319 \u00b0C<\/strong>). These values are seasonal averages<\/strong> for mid-July<\/strong> in the High Desert<\/strong>.<\/p>\n Winds across the region will generally blow at 10 to 20 mph<\/strong>, but may gust up to 30\u201335 mph<\/strong> in the afternoons, particularly on Thursday<\/strong> and Friday<\/strong>. These breezy periods<\/strong> may cause gust-fronts<\/strong> that enhance storm movement<\/strong> or cause isolated wind damage<\/strong>, especially in exposed passes and ridgelines<\/strong>.<\/p>\n This monsoonal push<\/strong> signals the official return of summer thunderstorm patterns<\/strong> across Southern California<\/strong>, with moisture-rich air<\/strong> capable of fueling short-duration, high-intensity events<\/strong>. Lightning<\/strong> and flash flooding<\/strong> remain the main concerns<\/strong>, particularly in burn scar areas<\/strong> and steep terrain<\/strong>.<\/p>\n Afternoon storm development<\/strong> is most likely after 1:00 PM PDT<\/strong>, with rainfall rates<\/strong> potentially reaching moderate to high intensity<\/strong> wherever storms manage to organize.<\/p>\n","protected":false},"excerpt":{"rendered":" San Bernardino Mountains, California \u2014 Thursday, July 17, 2025, 9:00 AM EDT The first monsoonal thunderstorms of the season are expected to develop across Southern California’s mountain regions starting today, Thursday, and continuing through Saturday, with the San Bernardino Mountains seeing the greatest risk for storm activity, according to the National Weather Service. Thursday brings […]<\/p>\n","protected":false},"author":2,"featured_media":6162,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-6161","post","type-post","status-publish","format-standard","has-post-thumbnail","category-news"],"yoast_head":"\n<\/h3>\n
Thursday brings a modest storm chance<\/strong><\/h3>\n
<\/h3>\n
Friday marks the peak of activity<\/strong><\/h3>\n
<\/h3>\n
Storm risk tapers into the weekend<\/strong><\/h3>\n
<\/h3>\n
Temperatures and winds in nearby cities<\/strong><\/h3>\n
<\/h3>\n
Seasonal shift toward monsoonal flow<\/strong><\/h3>\n