textproduct: San Diego

SYNOPSIS

Cool and windy this weekend with chances of light precipitation. Warmer early next week, then minor cooling and a slight chance of precipitation towards the middle of the week. Warmer and drier for the end of the week.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

New Aviation and Marine Discussion...

Today through tomorrow night...

In the short term, the forecasts remains on track with an approaching low pressure system, which is going to allow for an increase of westerly winds, along with a chance of showers, especially for the coastal-facing slopes. The marine layer is becoming more dispersed this morning, with the passage of mid to high level clouds overhead. There could be some patchy areas of drizzle this morning, especially along the foothills. By later in the day, there will be an increase of onshore flow, and developing showers over the inner waters of the SoCal bight, which will move onshore by later this afternoon and throughout the evening, and on into tomorrow. The overall low to mid-level flow will bring about the best chances and highest rainfall rates for the western-facing slopes within San Diego County. As of now, the best rainfall rates of possibly up to near an inch will look to occur around the Palomar Mountain area through Monday. Showers will taper off a bit going into Sunday, although there will still be enough forcing overhead to result in a few isolated showers developing throughout the afternoon. Winds will also continue to increase and become rather strong and gusty by later in the day, especially for the higher elevations, where gusts of 45 to 55 mph are expected by later this afternoon. Strongest winds will occur along the desert slopes, and through the mountain passes and canyons. There could also be occasional gusts of up to 65 mph. Blowing dust will also be possible for the areas with the strongest winds across the deserts, mainly within the Coachella Valley. Temperatures will also be on the chilly side for this weekend, and generally running around 5 to 15 degrees below the seasonal average for this time of year for most locations.

Monday through Friday...

On Monday, there may still be a few lingering showers with continued onshore flow and a weak perturbation that will be propagating into the trough could enhance the development of these showers, otherwise conditions will begin to dry out. The overall longwave pattern shows a cut-off low becoming positioned well west of the region over the Pacific Ocean, however, depending on the track of this system as it begins to transition easterly could allow for there to be some showers, and possibly a few thunderstorms, developing by later in the evening on Wednesday and into Thursday as a possible track with one of the deterministic members has this U/L low passing just to the south of San Diego, over northern Baja California, by around Noon on Thursday. This is still subject to change, being that it is quite a few days out and that it is a cut-off low, which is a more difficult track to predict. Besides this, there will overall be a slight warming trend occurring throughout the week, with relatively drier conditions through the end of next week.

AVIATION

251200Z...Coast/Valleys...BKN/OVC low clouds based 1500-4500ft MSL have filled in from the coast and valleys and into the Inland Empire. Scattered to isolated light rain will be possible overnight and into the morning near coastal areas. Chances for rain will increase after 21Z from the northwest to the southeast and last through the end of the TAF period. Cloud bases will lower to MVFR cigs in and around -SHRA. Winds are expected to get breezy after 15Z along the coast and move inland after 19-20Z. Expect wind speeds 10- 15 kts with gusts up to 20-25kts.

Mountains/Deserts...Gusty winds out of the west this afternoon expected to reach 30-40 kts, locally up to 50 kts. Moderate up/downdrafts will be possible in lee of mtns. Areas of BLDU (3-5SM) along desert slopes and locally into deserts. After 19z, gusts in the desert valleys could periodically exceed 35 kts, including vcnty KPSP.

Rain will reach mtns around 01z Sun with intermittent SHSN above 6500-7000 ft MSL. Mtns shrouded in FG; vis 0-5SM in FG/SHSN.

MARINE

No hazardous marine conditions are expected through Wednesday, though brisk westerly winds 15 to 20 kts are expected this afternoon and evening through Sunday.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...Wind Advisory from 2 PM this afternoon to 11 AM PDT Sunday for Apple and Lucerne Valleys-Coachella Valley-San Diego County Deserts-San Gorgonio Pass near Banning.

PZ...None.