textproduct: San Diego

SYNOPSIS

Moderate to locally strong Santa Ana winds will continue along the coastal mountain slopes, foothills, and into the valleys through Monday. Periods of weaker Santa Ana winds will continue through the remainder of next week. A warming trend develops this weekend, with temperatures peaking around the middle of next week. Wednesday and Thursday will likely be the warmest days.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

Update: Mild Santa Ana conditions continue to impact the region, and will continue to do so going into the early part of next week, although these winds are expected to gradually taper off through then each day. At this hour, there are still some wind gusts over 50 mph occurring within the highest elevations of the mountains of San Diego County. Sill Hill reported a gust of 67 mph for the previous observation. Expect that these winds will weaken for some of the inland areas enough to allow for sufficient radiational cooling, and therefore there could some areas of frost possible within some of these wind-sheltered valleys for tomorrow morning. Winds will periodically decouple and weaken for some of the lower elevations overnight, but then increase again throughout the late morning thru afternoon tomorrow, once the winds mix down to the surface. These offshore winds have helped to dry out the lower levels, so no marine layer clouds are anticipated through at least Tuesday. Temperatures will continue to be on a gradual warming trend through the mid part of next week, with mostly clear skies and no precipitation expected through then.

Previous discussion submitted at 130 PM:

Clear skies region-wide earlier this morning as moderate easterly Santa Ana winds continue to funnel through west facing slopes and passes. The strongest upper level northerly winds have moved eastward and the gusts have reduced considerably in the past 24 hours over the Santa Ana and San Bernardino County foothills. Gusts are now 40-55 mph around the Cajon Pass and mostly below 40 mph though the Inland Empire and Orange County inland areas.

The surface pressure gradient between Southern California and areas a few hundred miles east and northeast of us remains strong, allowing for elevated winds to continue for the areas mentioned above as well as strong East winds over the San Diego County mountains. Gusts 50-65 mph and locally higher are expected for the San Diego County mountain western slopes near peaks and passes through early Monday. Winds reduce slightly thereafter but remain strong with periods of gusts to 50 mph remain possible through at least Wednesday, as easterly 700 mb winds remain robust. There is some uncertainty regarding the Santa Ana winds after Wednesday, although most model guidance suggests a continuation of the offshore flow. The CW3E WRF maintains weak to moderate northeast and east pressure gradients between SoCal and the interior through next Friday. Medium range models continue to highlight modest mid-level easterly flow over our region until at least next weekend.

Due to the abundance of dry air at the surface, nighttime temperatures will drop into the 30s in wind-sheltered valleys tonight and potentially Sunday night. At the same time, high temperatures will be increasing a few degrees each day through Wednesday. Lowland temperatures top out around 70 degrees today and are eventually forecast to top out around 80 degrees Wednesday afternoon.

WPC 500mb height clusters are in good agreement that the strong upper longwave ridge over the Pacific Northwest will continue to amplify northward. While the ridge axis will continue to be lined up along the west coast, SoCal may be far enough south enough to see heights come down slightly with an outside chance for an upper cutoff low to develop over northwest Mexico and bring down temperatures near average and enhance cloud cover. Nevertheless, there is moderate confidence for peak temperatures next week to occur Wednesday and Thursday, then cool off slightly into the weekend.

As long as the offshore flow persists, relative humidity will remain low. Daytime RH drops into the 10-20% range through at least Tuesday , with overnight recoveries capped at only 35-40% for most of the region. Fire danger will be elevated as a result although limited as the fuel moisture levels are high from recent rains.

AVIATION

110330Z...Coast/Valleys/Mountains...Clear skies prevailing. Northeast and east winds gusting generally 30-45 kts along coastal slopes with 25-40 kts downwind of the Cajon/Banning passes into the Inland Empire and parts of Inland Orange County/eastern San Diego Valleys. Lighter surface winds overnight with periods of LLWS with mod up/downdrafts downwind of coastal slopes through 18z Sun. Offshore wind pattern continues through the remainder of the weekend, with slightly weaker winds by Monday morning and the strongest gusts more confined to the mountain slopes.

Deserts...VFR conditions through Sunday evening. Elevated northeast winds staying mostly confined to desert foothills with gusts 15-25 kts.

MARINE

Localized easterly wind gusts near 20 to 25 knots sporadically through this weekend. Otherwise, no hazardous marine conditions expected through Wednesday.

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 Orange County Inland Areas-Riverside County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Valleys-Santa Ana Mountains and Foothills.

High Wind Warning until 1 PM PST Sunday for San Bernardino County Mountains-San Diego County Mountains-San Gorgonio Pass near Banning.

PZ...None.