The heat wave has ended due to a weather disturbance moving through Northern California, bringing cooler and breezier weather for mountains and deserts into Saturday. Strongest wind conditions for Saturday afternoon and evening. Dry air has moved in from the north and will continue to spread southward resulting in lower humidity and has ended the monsoon. Greater coverage of morning low clouds is expected for coastal areas over the weekend with the low clouds becoming patchier again next week. Also for next week, there will be a gradual warming trend along with a slow increase in humidity. There is uncertainty when the next threat for thunderstorms occurs but slight chance is in the forecast for late next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
.Evening Update, Another day of triple digit heat was had across much of the deserts into parts of the Inland Empire this past afternoon. The good news is that cooler air will be coming into the picture across the region, allowing us to finally expire the Excessive Heat Warning over the lower deserts. High temperatures across this region will be near 110 by Saturday, and get closer to 105-110 by Sunday and Monday as onshore flow leads to cooling. The onshore flow will bring breezy weather for mountains and deserts again on Saturday with west winds gusting near 25-40 MPH across passes and deserts.
The high pressure system that was giving us hot weather earlier in the week will push eastward into early next week, then expand back toward SoCal. The trough overhead will enhance the marine layer this weekend, with more lower cloud coverage near the coast. As the high expands later next week, we can expect another warm up across the area.
.Previous Discussion (12:21 PM Today),
We finally have cooling of air mass for Saturday (22-28C at 850 mb level), in the wake of the disturbance that tracks across northern California. There is also a better push of more organized low clouds and marine air into the valleys. Fire weather conditions deteriorate because of drier air and increasing onshore flow for all deserts and the mountains with the peak of the westerly winds on Saturday. The coolest day for most areas will be Sunday.
Weather pattern warms next week but still considerable uncertainty as potential upper level wave arrives during midweek from Mexico on the backside of the heat dome rebuilding over the Great Basin and 4-corners region. This could bring back monsoon moisture as well for late week.
270330, Coast, Low clouds moving onshore 05-06Z this evening with more uniform coverage than last night, covering coastal areas and parts of the western valleys overnight. Bases will be around 800- 1200 feet MSL with local vis reduced 1-5SM on higher coastal terrain and in western valleys. Low clouds scatter out Saturday by 15-18Z.
Mountains/Deserts, Westerly winds tapering this evening through overnight in mountain passes into adjacent deserts. Similar to slightly stronger winds expected after 21Z Sat, gusting to 25-35 kt through Sat evening. MOD up/downdrafts in lee of mountains.
No hazardous marine conditions are expected through Wednesday.
Ca, None. PZ, None.
