Dry weather will continue through the Thanksgiving holiday weekend. High pressure currently over the western states will gradually weaken through this period, leading to a cooling trend and a return of marine layer low clouds and fog. Another weather system will move into the western part of the country by the middle of next week, which may bring a greater chance of showers or continued dry weather.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Variable high clouds cover much of the region this evening. Low clouds/fog are absent due to the Santa Ana winds which also brought warmer conditions west of the mtns this afternoon. Temperatures reached the 80s in some parts of the inland valleys and 2 locations set new records for this date. Sfc pressure gradients remain offshore with -5.2 mb SAN-DAG. In the last hour, the windiest locations reported east winds gusting 30-35 mph.
From previous discussion, Winds will become weaker and more localized closer to the coastal slopes tonight through Thursday morning as the pressure gradient weakens. High pressure will remain aloft for the Thanksgiving holiday, leading to communities seeing highs about 5 to 10 degrees above normal. An area of low pressure off to the west will will help bring in high clouds across the region as well. The flow will become more zonal as high pressure weakens over the southwestern U.S. By Friday. This will bring greater onshore flow and cooling on Friday into the weekend. High temperatures will be within 5 degrees of normal by this weekend.
Model guidance continues to show a low pressure system tracking farther inland across the Great Basin by this weekend. This matches the precipitation trends which have gone down when looking at past models runs over the previous few days. The NBM shows that the chances for measurable precipitation have gone down to around a 10% for Sunday into late Sunday night, mainly across the mountains. Confidence continues to increase on Sunday being cooler with limited precipitation amounts.
By the first half of next week, SoCal will see highs near average with dry weather. An area of low pressure will move into the Pacific Northwest sometime around next Tuesday, pushing southward by the middle of next week. The path of this weather system is still highly uncertain. Out ahead of it, offshore flow will begin to come back to the region by Monday and Tuesday. Winds as of now look fairly weak, but this may change as we head closer to this event. If this weather system goes far enough to our west, the chances for precipitation will increase. If it stays farther inland over the desert, we would receive little or no precip. Nbm POPs are around 20-30% for much of the region by this time, but things will change as we head closer and see where the exact track of the system ends up.
270345z, Coasts, VFR conditions expected through Thu.
Valleys/Mountains/Deserts, VFR conditions expected through Thu. E to NE winds gusting 25-35 kt in mountain passes with localized weaker gusts to 15-25 kts stretching into valleys below mountain passes through 18Z Thu. Areas of LLWS/low-level turbulence along foothills/coastal mountain slopes Thu AM.
No hazardous marine conditions are expected through Monday.
Ca, None. PZ, None.
