textproduct: San Diego

SYNOPSIS

Unusually warm temperatures continue today, with highs ranging from 8 to 12 degrees above average. A gradual cooling trend will follow for Sunday through Tuesday/Wednesday, bringing temperatures around 5 degrees above average for midweek. The upper level ridge moves back west towards Las Vegas and restrengthens in the latter half of the week. There is increasing confidence that this setup could provide the hottest temperatures of the Summer thus far.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

Today through tomorrow night...

Latest radar imagery reveals that there are some showers, and a few embedded thunderstorms moving up over northern Baja California at this hour, with a few of these showers beginning to move over portions of SE San Diego County. This will continue to move up from the south in the form of a lot of altocumulus and altostratus, with as few showers, and some of these may make it through the drier PBL and reach the ground. With this in mind, the marine layer has been disrupted a bit with the presence of the mid-level clouds passing overhead. Any bases that have struggled to form have generally been based around 1000-1500 MSL. There may also be some rain drops felt, even through the low level clouds, due to the convective subtropical mid-level clouds moving overhead.

When analyzing the near-storm environment on SPC, it is evident that the majority significant instability remains confined over the deserts, with the highest values of MUCAPE (although it is well- capped). Since there is some elevated instability associated with this monsoonal wave as it transitions up over San Diego County this morning, it may likely produce a few rain showers, and possibly even a rumble of thunder can he heard all the way down to the coastal areas. Depending on how much it clears out by later this morning will determine whether or not it will warm enough to get thunderstorm development over our mountains by later this afternoon. As this moisture moves out by tomorrow with more southwesterly flow predominantly taking over in the mid levels, it will allow for more drier conditions to settle back in for tomorrow with likely little to no cloud development over the mountains for Monday.

Tuesday through Saturday...

From tuesday into Wednesday, the ridge will weaken slightly a shift a little further eastward with slightly better troughing influence upstream which will allow for temperatures to be slightly cooler, and only around 5 degrees above the seasonal average by Wednesday. The drier air advection in the mid levels out of the southwest will help to hinder any afternoon monsoonal development. Then, as the ridge begins to build a bit and expand/retrograde back towards the west beginning Thursday, it will allow for temperatures to gradually warm again up to around 10 to 15 degrees above the seasonal average, especially by Friday. There will also be an influx of mid-level moisture again out of the southeast as these originate over Arizona and Sonora, Mexico, and then transition over our region. The ridge will begin to slowly weaken and flatten a bit going into Saturday, translating to only slightly cooler temperatures to begin the following weekend, although still quite hot... even for summertime.

AVIATION

260600Z....Coast/Valleys...Patchy low clouds have formed offshore and are moving into coastal TAF sites based near 1200-1400 ft MSL. Clouds will continue to move further inland up to 15 miles and northward through 12z with VIS restrictions for where clouds intersect terrain. Clearing likely by 16-17z. Low clouds with similar or slightly higher bases move back in again Sunday evening after 03z Mon.

Mountains/Deserts...VFR with FEW-SCT high clouds AOA 20k ft MSL through the period. Cu 10-15k ft MSL builds over the mountain peaks Sunday afternoon.

MARINE

Calm conditions over the weekend with waves 2 to 4 feet and afternoon wind gusts near 15 kts or less through Monday. Waves increase in the outer waters mid to late week with waves expected around 5 to 7 feet.

BEACHES

A long-period southwesterly swell builds Sunday, keeping surf around 3-5 feet with sets to 6 feet through Sunday evening. Monday and Tuesday, the southerly swell will increase to 3 feet with a period 17 seconds, elevating surf once again to 4-6 feet with sets to 7 or 8 feet. Highest surf is expected along south-facing beaches. High rip current risk and a longshore current threat will last through the upcoming week.

In addition to elevated surf, tides are expected to increase to a height of 6.0 to 6.5 feet MLLW by Sunday and continue at that height through most of the week. The combination of surf and tides will result in minor coastal flooding during high tides.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement through Wednesday afternoon for Orange County Coastal Areas-San Diego County Coastal Areas.

Heat Advisory until 8 PM PDT Monday for Orange County Coastal Areas-Orange County Inland Areas-Riverside County Mountains- San Bernardino County Mountains-San Diego County Coastal Areas-San Diego County Mountains-San Diego County Valleys- Santa Ana Mountains and Foothills.

Extreme Heat Warning until 8 PM PDT Monday for Apple and Lucerne Valleys-Coachella Valley-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Deserts- San Gorgonio Pass near Banning.

PZ...None.