Chino Hills, CA Weather

Synopsis

Calm and warmer weather will occur through Wednesday. The warmest days of the week will be today and Monday with marine layer clouds returning by Tuesday or Wednesday morning near the coast. Cooler and breezier with increased chances for precipitation entering the picture by later in the week.

Discussion

FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

...UPDATED AVIATION DISCUSSION...

Mostly clear skies are seen on satellite this morning with increasing mid-level clouds to our west over the Pacific. Models show these clouds moving over the region late this afternoon through the night, bringing a nice sunset for some. High temperatures will be slightly warmer today than yesterday. NBM chances are moderate to high in seeing temperatures eclipse the 80 degree mark across inland Orange County, the northern Inland Empire and inland valleys of SD County. Temperatures in these areas cool a few degrees by Tuesday and Wednesday, with other regions staying fairly similar from day to day over the next few days. As pressure heights subtly lower, this will increase the depth of the marine layer. Low clouds and patchy fog may form offshore and near coastal areas as early as Tuesday morning, with higher confidence on this occurring by Tuesday night into Wednesday morning.

The weather pattern begins to shift by Thursday into next weekend. Like yesterday, models continue to show an area of low pressure entering the Pacific Northwest around Wednesday into Thursday, where a large troughing pattern begins to set up across the West Coast. This will bring a deeper marine layer and a cooling trend to the region starting Thursday into next weekend. Increased cloud cover with chances for precipitation may begin as early as late Thursday night, though some model solutions have begun to push back rain chances later in time. The broad troughing pattern will bring temperatures back below normal with breezier conditions across the mountains and deserts. This pattern may also bring little to no rainfall at first, where Thursday night into Friday may be mostly dry with only isolated light showers for some.

During this time period, model guidance begins to diverge on how the direction/strength of the Pac NW low interacts with the possibility of a shortwave with increased subtropical moisture that may poise itself somewhere to our south or west over the Pacific. Details in where these systems develop and trek will be key in determining how much precipitation falls across the region. Does the Pac NW low stay further north and the potential subtropical shortwave stays further to the south, giving us minimal rainfall? Do they combine forces, giving us a wetter scenario? Something in between? Whatever occurs, confidence continues to increase for wetter and cooler conditions for the Halloween weekend, so make sure to continue to monitor the latest forecast.

Aviation

251100Z...Generally VFR conditions across the region through the period. 20% chance for very patchy low clouds based 500-1000 ft MSL over nearshore waters and along the coastline tonight. No impacts expected for coastal TAF sites at this time.

Marine

Winds gusts near 20 knots possible in the outer coastal waters Monday afternoon and evening. Otherwise, no hazardous marine conditions are expected through Thursday.