textproduct: San Diego

SYNOPSIS

Cooler weather each day with a deeper marine layer making it further inland into mid-week. Afternoon temperatures through Wednesday will generally be 2-5 degrees below normal. High pressure strengthens late week with warmer temperatures into the weekend.

..UPDATED AVIATION DISCUSSION FOR 00Z TAF PACKAGE

Mid level water vapor satellite places an upper level low over Oregon and Washington, poised to continue to move across the northern portion of CONUS. This low brought an end to the abnormally hot weather SoCal had experienced the past week, and allowed for the marine layer to redevelop and thicken this morning. This system also has aided in tightening the gradient, producing stronger onshore flow with afternoon gusts today and tomorrow around 35-50 mph through wind-prone passes and along the desert slopes. While this low will meander eastward along the border with Canada on Monday, a second trough will swing down from the PacNW and form a closed low over southern Oregon and NorCal by Wednesday. This secondary low will reinforce the cooler weather we've had, maintaining a cooling trend through at least Wednesday. As such, high temperatures Mon-Wed will hover around 2-5 degrees below normal with overnight low temperatures also slightly below normal for everywhere but the deserts which will remain a bit hotter with slightly better humidity to the east. The marine layer will continue to deepen and make it further inland each morning into at least mid-week, with some hi-res guidance indicating it may be deep enough to sustain some patchy morning drizzle on Tuesday, although chances of this occurring are low.

The low will weaken a bit as it becomes absorbed in the upper level pattern and pulled northward later this week. As the low departs, subsidence over the Pacific to the southwest of San Diego will increase, with upper level ridging developing over CA Friday and Saturday. This will return the area to warming trend for the late week, although guidance is chaotic with the long-range pattern as the GFS attempts to return the region to troughing Sunday and beyond while the ECMWF maintains the warmer ridge.

AVIATION

140000Z...Coasts/Valleys...There is much less cloud cover across the California Bight this afternoon, with only stray patches of FEW low clouds above 2000ft MSL across the coastal areas. However, expect low clouds to increase in coverage between 02-06z, with widespread CIGs across San Diego County by 06z Monday. Clouds spread northward into Orange County through 09z with about 20 miles of inland extent. Slightly less inland extent expected across the Inland Empire compared to last night, with only a 30-40% chance of CIGs between 12- 16z. VIS reductions of 4-6 SM in elevated inland valleys in HZ/BR, and down to 0-5 SM where clouds intersect terrain in the IE and surrounding foothills. Clouds scatter back out between 15-17z Monday.

Mountains/Deserts...VFR conditions prevail through the TAF period; typical late afternoon S/W winds gusting 15-25 kts (up to 35 kts through the Banning Pass) expected, weakening after 06z Monday.

MARINE

West-northwest winds expected to gust up to 20 knots in the outer coastal waters this afternoon. Otherwise, no hazardous marine conditions are expected through Thursday.

SGX WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...None.