A strong area of high pressure will continue to bring hot weather through Friday. Ever so slight cooling occurs by the weekend into Monday as high pressure moves to the northeast. The high pressure's movement will bring in greater monsoonal moisture for our area by Sunday into at least the latter part of next week. This will bring increased rain and thunderstorm chances to inland areas with greater humidity for the entire region.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
A stronger inversion is seen on this morning's atmospheric sounding, near 13C, which will give the marine layer clouds a tough time to clear the beaches today. The heat continues away from our coastal areas again with highs in the triple digits for our deserts, and well into the 90s for far inland valleys and southern mountain areas. Moderate to high heat risk is again in the forecast through Friday for these areas, so please take breaks and drink plenty of water if you must be outside.
High pressure over the region today and Friday will begin to move to the northeast this weekend. This will knock temperatures down a few degrees for areas away from the coast. As the system moves northeast, southeasterly flow around the high will bring greater humidity and monsoonal moisture to the region starting on Sunday. This will bring a slight chance of thunderstorms mainly to the northern mountains in the afternoon. Limiting factors for convection to form are a lack of instability as well as getting the atmosphere moist enough after a very hot dry air mass having been over us this week. Models indicate a continued uptick in moisture by Monday with a better moisture feed pattern aligning over SoCal. The best chances for showers and thunderstorms will be over the mountains and deserts, locally into the far eastern valleys.
Models indicate the high moving and expanding into the northern Great Plains by the middle of the week, retreating back across the Intermountain West by the end of next week. Monsoonal moisture looks to continue moving into the region through much of next week around this system, bringing daily chances for showers and thunderstorms across the mountains and deserts. With this flow pattern, Sunday and beyond looks to be humid for all areas of our region as well! As the high retreats closer to the region, temperatures make a rebound by the middle of the week. This will bring moderate to high heat risk for areas away from the coastal regions, including the valleys of Orange and San Diego County.
092330z. Coast, Areas of low clouds based around 1200-1500 feet MSL will push ashore after 03Z and cover all coastal areas overnight by around 09Z. Cigs will lower to 800-1000 feet overnight. Vis restricted 1-5SM over higher coastal terrain. Scatter out Friday 16- 18Z, but patchy low clouds to persist along immediate coast. Low clouds around 1000-1500 feet MSL to move ashore after 04Z Saturday.
.Valleys/Mountains/Deserts, Mostly clear and VFR conditions to continue through Friday evening. Onshore winds 25-30 kts through mountain passes and locally into deserts.
No hazardous marine conditions are expected through Wednesday.
Astronomical high tides of 7.0-7.2 ft are forecast July 12-14. Higher than normal tides combined with a modest south swell (3 ft swell 14/15 seconds from 190 degrees) generating surf of 4-6 ft may result in areas of coastal flooding in low lying areas, boardwalks, beach parking lots, and beach adjacent streets during evening high tides.
Ca, Heat Advisory until 8 PM PDT Friday for Riverside County Mountains-San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Mountains.
Extreme Heat Warning until 8 PM PDT Friday for Coachella Valley- San Diego County Deserts-San Gorgonio Pass near Banning.
PZ, None.
