High pressure over the eastern Pacific will keep temperatures slightly above normal through early next week across Southern California. Moderate HeatRisk is expected for the deserts each day with localized Major HeatRisk in the lower deserts over the weekend. The marine layer will remain relatively shallow with morning clouds remaining confined to coastal areas and western valleys through the weekend.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Satellite imagery shows low clouds struggling to form over coastal areas early this morning. This may be somewhat attributed to anomalously warm sea surface temperatures keeping the marine layer inversion slightly weaker than usual. However, the HREF maintains that marine layer clouds will fill into coastal areas and western valleys by sunrise this morning. With the upper pattern holding steady over the next few days, the expectation is for morning clouds to continue for these areas through the weekend. Thereafter, the marine layer may deepen slightly going into early next week.
An upper ridge centered over the eastern Pacific will provide just enough influence to keep both high and low temperatures slightly above normal from today onward for the coast to the mountains and 5 to 10 degrees above normal in the deserts. Record highs do not look to be threatened, though a few record high lows may occur near the coast, aided by the aforementioned warm SSTs. Moderate HeatRisk is expected for all desert locations and portions of the Inland Empire from Thursday through early next week.
Weak ridging over the south-central CONUS will be positioned such that elevated PWATs are expected to move into the region from the south by Friday. Nbm currently indicates that temperatures will reach the low 100s in the High Desert and graze 110 in the lower deserts this weekend. However, depending on the strength of this moisture surge, temperatures may be a few degrees lower than anticipated. At the very least, increased coverage of high clouds is expected over the region through the weekend.
By early next week, the ridge over the eastern Pacific will weaken slightly as it migrates toward the western CONUS. Most ensembles show anomalies in upper heights centered over the Pacific Northwest, while the Southwest is largely spared of increasing heights. In fact, the NBM shows a few degrees of cooling across the region through early next week. Model solutions diverge further by mid-to-late next week, but ensembles lean toward further cooling with increased chances for upper troughing over the western CONUS.
101800z, Coast/Valleys, Low clouds have cleared the coast with a few clouds wafting in around 1000-1600 ft MSL. Low clouds will start to push in again after 23Z beginning along San Diegos coast line and fill in after 03Z Thursday. Bases are expected to be around 800-1200 ft MSL. Minor vis reductions (4-6SM)will be possible for elevated coastal terrain. Clouds clear the coast after 17-18Z Thursday.
Mountains/Deserts, VFR conditions expected through the TAF period.
No hazardous marine conditions are expected through Saturday.
Ca, Beach Hazards Statement through Thursday afternoon for Orange County Coastal Areas-San Diego County Coastal Areas.
PZ, None.
