Near normal temperatures expected this weekend. Thunderstorm chances over the mountains and locally into the deserts each afternoon Sunday through much of the forecast period. Above average high and low temperatures return early to mid next week. Coastal flooding will impact beaches Sunday through Tuesday with evening high tides exceeding 7 feet.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
Low clouds have scattered out of coastal San Diego County, and will be a bit more stubborn in Orange County, partially clearing this afternoon. Elsewhere, high clouds are streaming in from the south as an area of showers crosses over the northern portion of Baja California. This may bring greater cloud cover across portions of San Diego County this afternoon and early evening. The marine layer remains thinner, and will come in later tonight into the mid morning for coastal areas. This low cloud pattern looks to continue over the coming days.
The high pressure system that has brought the hotter weather has moved off to the northeast. This will help bring temperatures closer to normal, though parts of the mountains and high desert will be about 5 degrees above average. Models indicate humidity and PWAT values increasing later today into Sunday as the ridge moves over the Intermountain West. The hot dry air mass will struggle some to produce accumulating rainfall on Sunday, so slight chances are in the forecast for mountain regions into portions of the high desert. The high pressure system expands and moves into the northern plains by Monday as a trough offshore deepens. These two system will create to better funnel this monsoonal moisture into the desert southwest as PWATs/humidity peak, bringing the greatest chance for storm activity over the short term period. The mountains and deserts have the greatest chances (35-60% chance) to see bouts of heavy rainfall, lightning, and small hail Monday afternoon and evening. Confidence is still low on how far west this moisture and instability will move during this time period, so chances for any storm development west of the mountains is currently at or below 10 percent.
By Tuesday, models are in fair agreement of the high over the Great Plains shifting further to the east, displacing some of the moisture over our region. This will aid in a lower chance (20-35%) of showers and thunderstorms over the northern mountains and deserts. Models show the high may retrograde back to the west by Wednesday into the end of the week, which would provide a greater storm chance to inland areas.
With the incoming monsoonal moisture and thunderstorm threat, there will also be higher humidity and hot weather! We all will start to feel greater humidity from the coast to the deserts by Sunday, which will last into much of the upcoming week. Along with this, hotter weather will return by the middle of the week (Tuesday - Thursday) for many areas that saw it this past week, with a larger emphasis on valleys west of the mountains. Nbm shows high temperatures well into the 90s east of Interstate 5 in Orange County and east of Interstate 15 in San Diego County, with highs near 100-105+ across the Inland Empire. With these temperatures, humidity, and warmer overnight low temperatures, HeatRisk will be higher, so please plan ahead!
120000z. Coast/Valleys, Increasing high clouds AOA 15kft MSL this evening, with high clouds spreading into much of the region overnight. Patchy low clouds will develop again this evening and move inland, likely around 900-1200ft MSL, but may be less widespread given the influx of high clouds. Low clouds will move into San Diego County generally after 03z, and up into Orange County after 08z. VIS restrictions where stratus intersects terrain. Low clouds will clear back to the coast around 16z, but high clouds will prevail through the afternoon and evening on Sunday.
.Mountains/Deserts, Increasing mid/high clouds AOA 15,000 ft MSL today and tomorrow and generally unrestricted visibility. There is a slight chance of thunderstorms over the mountains Sunday afternoon, with any storm capable of gusty and erratic winds and low visibility due to heavy rain.
No hazardous marine conditions are expected through Friday.
Ca, Beach Hazards Statement from Sunday morning through Tuesday evening for Orange County Coastal Areas-San Diego County Coastal Areas.
PZ, None.
