textproduct: San Diego

SYNOPSIS

Moderate to locally strong Santa Ana winds will continue along the coastal mountain slopes, foothills, and into the valleys through Sunday. Periods of weaker Santa Ana winds will continue beyond that. Patchy frost is expected this morning in wind sheltered valley locations. A warming trend develops this weekend, with temperatures peaking around the middle of next week.

..Updated Aviation and Marine sections

The offshore flow and Santa Ana winds have begun in earnest, with some foothill spots gusting over 50 mph, and even some valley locations gusting over 30 mph. These winds will most likely peak today in the late morning through early afternoon. Top gusts in the top spots will achieve 60+ mph with really isolated gusts close to 80 mph. Winds continue quite relentless in these areas through the weekend, only slightly weaker and slightly less widespread than today's winds. Yesterday's cold system that dove into Arizona has set up efficient offshore flow both aloft and at the surface. While the upper support weakens slightly, the surface gradient tightens slightly, so nearly a wash as far as the wind trends go. Fire potential rises as humidity dips during this windy event, but the fuel moistures remain quite high (green and growing vegetation from recent rains) to thankfully mitigate the fire potential. There are some frosty conditions in parts of the inland wind-sheltered valleys this morning.

An upper ridge of high pressure builds over California this weekend and continues to expand and strengthen next week. But with low pressure over northwest Mexico, the flow aloft continues to be offshore (northeast). Surface gradients weaken so winds should also weaken a little, but areas of gusty winds will persist. It's going to be a really long Santa Ana episode. A steady warming trend will boost temperatures a couple degrees each day into Wednesday. Look for lots of 70s emerging at lower elevations this weekend. By Wednesday there should be some areas reaching into the 80s. The dry air mass will allow temps to drop efficiently each night, especially when/where winds calm down, but nighttime temps will remain really mild in the 60s in those areas where mixing winds persist. No meaningful change in the pattern is shown by ensembles toward next weekend. Some solutions show an arctic blast coming down the interior West. Others keep the ridge firmly in place along the West Coast. Confidence is high our weather will remain dry and warm into next weekend.

AVIATION

091615Z...Coast/Valleys/Mountains...SCT clouds AOA 20k ft MSL. Northeast winds currently gusting 40-55 kts along coastal slopes mostly north of San Diego County. Gusts 25-40 kts through the Inland Empire from KONT to KRIV, and into inland Orange County (including KSNA). Strongest winds occurring before 20Z Fri. Winds turning more easterly 21Z Fri-03Z Sat, expanding in coverage in more of San Diego County and more of the inland valleys. Periods of LLWS and moderate up and downdrafts downwind of coastal slopes (i.e. KONT, KSNA, KSBD). Wind pattern continues through much of Saturday.

Deserts...VFR conditions through the period. Strong northeast wind gusts staying mostly confined to mountain slopes, with winds generally below 20 kts.

MARINE

Northeast to east winds will occasionally gust to 20 knots this weekend. Otherwise, no hazardous marine conditions expected through Tuesday night.

SKYWARN

Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.

SGX WATCHES/WARNINGS/ADVISORIES

CA...Wind Advisory until 1 PM PST Sunday for Riverside County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Mountains-San Diego County Valleys-San Gorgonio Pass near Banning-Santa Ana Mountains and Foothills.

High Wind Warning until 1 PM PST Sunday for San Bernardino County Mountains.

Wind Advisory until 1 PM PST Saturday for Orange County Inland Areas.

PZ...None.