Cooler weather with showers moving through the area today will transition to slightly warmer and drier weather by Thursday and Saturday. A more robust weather system will enter the area Sunday through the early part of next week. This will bring more widespread rainfall, mountain snow, and windier conditions. Cooler temperatures will prevail for much of next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, New Aviation Discussion for the 00z TAF Package..
Showers across the region have become lighter over the past few hours. Winds continue to decrease as well, with gusts across mountain desert slopes near 25-40 MPH. Showers will continue to become more isolated through the afternoon hours. Low clouds continue to depart the region toward the southeast, where brighter conditions are being seen closer to the LA County line. A low pressure system over the Bay Area will move southward over the region by Thursday into Friday morning. The system will be weak and moisture starved, so rain chances are low. If any rain falls, it would be over the mountains or the lower deserts. Though the troughing pattern will remain over us, temperatures will slightly warm with highs near average. High temperatures will be in the 60s west of the mountains with highs 50s/60s in the mountains. The trough passes to the east later on Friday into Saturday, and will be replaced by a weak ridge. This will bring sunnier and slightly warmer weather with highs near to slightly above normal.
Models continue to hone in on a large area of low pressure moving down the West Coast. This system will bring a better chance for more widespread rainfall and mountain snow. Timing of models shows some spread on the exact start timing of the precipitation on Sunday. As of now, light showers ahead of the storm would start early Sunday morning across the LA Basin and into the afternoon hours further south and east. The exact path of system will be crucial to exact rain and snow amounts, and right now, that still remains to be seen as models begin to show differences. Nbm points to around a 65% chance in seeing rainfall over 1" over populous areas of Orange County, where this chance goes down to 15% from Monday-Wednesday. Chances go down slightly into western San Diego County. A weak atmospheric river associated with this system will move through the area on Monday, where the heaviest precipitation is expected. Ivt values from models depicts values near 400-500 kg/m/s. This will bring an increased flood threat for areas along and west of the mountains, especially along the coastal slopes. While exact snow amounts remain uncertain, snow levels will be closer to 6,000 feet, bringing areas of heavier snowfall to areas like Big Bear Lake.
The troughing and active weather pattern looks to stick around by Tuesday into the middle of next week. Model details are not as defined, but a series of troughs may move in from the north to provide more chances for rain and mountain snow. Nbm chances for precipitation are moderate to high by Tuesday into Wednesday of next week. Next week will also feature cooler weather with highs up to 10 degrees below normal and windier conditions, especially in the mountains and deserts.
120000, Visible satellite shows high clouds beginning to exit the region from west to east as this storm system departs. SCT-BKN low clouds based mostly 2500-3500 ft MSL along with isolated -SHRA currently from the coast to the mtns. Low clouds and -SHRA will diminish by 06Z with VFR conditions prevailing across the region, thereafter. SCT-BKN high clouds AOA 20 kft return after 12Z Thu.
Satellite imagery also indicates mountain wave activity currently along the desert slopes of the mountains. However, winds and associated mountain wave activity will be decreasing through this evening. Potential for MOD up/downdrafts through 03-06Z.
No hazardous marine conditions are expected through Sunday.
Strong westerly swell (260-280 degrees) with a 11-12 second period will lead to elevated surf of 3-6 feet through this evening, with localized sets to 7 feet, highest in southern San Diego County. Surf will diminish early Thursday morning.
Ca, None. PZ, None.
