Category Archives: weather|southern california

Southern California Warming Up and Drying Out?

Trail leading to Lasky Mesa at Ahmanson Ranch.

There are still a few rogue mud puddles out at Ahmanson ranch, but the Goldfields are blooming, the meadowlarks singing, and it feels like Spring!

Last week it looked like our rain season might not be over. Now I’m beginning to wonder. This week the GFS and ECMWF forecasts have been much drier in Southern California, with most of the activity focused on the Pacific Northwest. No significant rain is forecast here over the next week, and both the 6-10 and 8-14 day forecasts project below average precipitation in Southern California.

If these medium range forecasts are on the mark, March rainfall for Downtown Los Angeles (USC) will fall well below the 3.14 inch norm. Normal April rainfall is 0.83 inches, and May only 0.31 inches. Beyond March it becomes increasingly unlikely that a big rain event will significantly boost our rainfall total.

Since November 1, Downtown Los Angeles has recorded 8.80 inches of precipitation. This is about what would be expected during a La Nina, and within the range indicated in the composite precipitation map included in the post Southern California 2008-2009 Winter Precipitation Outlook, back in October.

In his March 6 post, Ed Berry suggested the possibility of “more energetic progressive troughs” in the western U.S in the week 2-3 timeframe. That wouldn’t necessarily result in rain in Southern California, but might improve our chances. Numerical weather model performance generally suffers during seasonal transitions, so maybe there are still some surprises lurking in the Pacific. We’ll see!

Malibu Creek State Park Shadow & Sun

Malibu Creek State Park

My trail running shoes had not been wet or muddy since sometime in December. During the entire month of January, Downtown Los Angeles (USC) recorded about one-third of an inch of rain. Not only had it been dry, it had been warm. On a dozen of those January days, the high temperature topped eighty degrees, setting a new record!

But Winter had returned. The past three days, Los Angeles had received about 1.5 inches of rain, valley and foothill locations 2-4 inches, and some mountain stations as much as 5-7 inches. And more Winter weather was on the way. Excited about the change in the weather, today’s run was one with good muck and mire potential — the Bulldog Loop in Malibu Creek State Park.

We were not disappointed. Near Century Lake, mud the consistency of peanut butter pulled at our shoes and slowed the climb up Crags Rd, Further west, near the M*A*S*H site, calf-deep water on the trail washed the gunk off.


Pt. Dume from the Mesa Peak ridgeline.
The trail conditions on the remainder of the loop were more straightforward. From time to time, shafts of sun would pierce the clouds, resulting in a patchwork of shadow and sun that emphasized the rugged terrain. Along the crest, the ocean views were superb! Before descending to Tapia Park we ran out to Mesa Peak, and then followed the ridgeline to an overlook of the coast. (Marked peak 1800 on the topo.)

Including the side trip to the overlook, this variation of the Bulldog loop worked out to an exhilarating 16.5 miles, with an elevation gain/loss of about 2700 ft.

If current forecasts and outlooks for this month hold true, this won’t be our last wet and muddy trail run this February. In a couple of weeks, Los Angeles rainfall totals may climb above normal for the first time this rain season. We’ll see!

Some related posts: Fog Along Malibu Creek, Bulldog Loop and the Corral Fire

Blue Skies and Short Sleeves on Strawberry Peak

Mt. Baldy from near the summit of Strawberry Peak, in the San Gabriel Mountains.

My legs were still pretty worked from the Boney Mountain Half Marathon. Instead of backing off of the pace on my weekday workouts, I had continued to experiment with a change in running technique that was resulting in faster paced runs. I was excited about the increase in speed, but logging fast times on oft-run courses after a strenuous race doesn’t equal recovery. Neither does blasting up a peak in the San Gabriel Mountains.

But it was one of those impossible to ignore, blue sky, short-sleeved Southern California Winter weekends. This would be an unprecedented eighth straight January day that the high temperature in Los Angeles exceeded eighty degrees. In the yin yang of weather, the western half of the U.S. has been enjoying unusually warm temps, while the eastern half of the country shivered.

Taking maximum advantage of the good weather, yesterday I had done a little kayaking on the Kern River, this morning some rock climbing at Stoney Point, and now we were huffing and puffing up Strawberry Peak (6164′) — and doing it “for time.”

We had started at Red Box, the shortest and technically most moderate way to climb the peak. By this route it’s about 3.4 miles to the summit, with an elevation gain of roughly 1600 ft. About two-thirds of that distance is well-graded trail, the rest is steep use trail up a broad, brush covered ridge.

About halfway between Lawlor Saddle and the summit of Strawberry it became plainly and painfully evident that my legs had given their all. I complain. Miklos — always sympathetic — asks why I can’t go any faster.

On the final steep push to the summit ridge I try a different tactic to slow the pace, and tell a story about an unbelievably angry and aggressive raccoon I once encountered near here. But like President Jimmy Carter’s rabbit incident, it loses something in the telling. Redlined, we crest the summit ridge and sprint (relatively speaking) toward the summit.

On the summit, there is not a breath of wind. The view is exceptional. To the southwest, sunlight gleams on the waters of the Pacific near Palos Verdes, and to the west snow gleams white on Mt. Baldy. Some 90 miles distant, near Palm Springs, is the asymmetric silhouette of Mt. San Jacinto.

Soon we’re headed down. As I drop below the summit ridge, a snowball whizzes past my ear, crashing on the trail ahead. It has been warm and dry for weeks, but remarkably, there are a few patches of snow. It is a reminder that Winter is not over, and like the snow, is lurking in the shadows.

Green and Growing

Greening grass at Sage Ranch Park

Green beneath Summer’s bleached stalks, the growth of this grass at Sage Ranch reflects the near normal rain season we’ve had to date in the Los Angeles area, and over much of Southern California. Since the start of the water year on July 1, Downtown Los Angeles (USC) has recorded 4.66 inches of rain. When this photograph was taken, January 11th, 4.66 inches was almost exactly normal rainfall for the date.

However, as is so often the case in Southern California, this apparent normality is the sum of offsetting wet and dry periods. December’s precipitation was generally well above normal, but January has been dry, dry, dry. Today, the Los Angeles rainfall total is about 0.5 inch below normal, and every day it doesn’t rain, our deficit increases by about 0.10 inch.

So when might it rain? A very strong 200 kt Pacific jet stream has pushed up a high pressure ridge over the West Coast, blocking storms and warming temperatures. Big upper level ridges such as this are consistent with La Nina, and have been a recurring theme this Fall and Winter. Much of our rainfall and cold weather this season has occurred when an extended Pacific jet collapses or contracts, and a blocking ridge shifts west, opening the door to cold storms plunging down the backside of the ridge from the north.

Over the next 1-2 weeks, this is expected to happen again, but this time there is a wildcard in the mix. One of the reasons the Pacific jet is so strong is the active phase of the Madden-Julian Oscillation (MJO) is present in the Western Pacific. As described in this Climate Prediction Center document, this scenario sometimes leads to a heavy West Coast precipitation event.

It’s too far out for the medium range models to be of much help in assessing the likelihood of such an event developing. At the moment, about the only thing that can be said with some certainty is that a pattern change is in the works, and by the end of January there is a chance of some rain in California and the West. We’ll see!

Related post: Southern California 2008-2009 Winter Precipitation Outlook, Snow on Oat Mountain

Chumash Clouds

Sunset view of Simi Valley, with Boney Mountain and Conejo Mountain in the distance.

Clouds moving onshore ahead of a low pressure system that is expected to produce rain in Southern California Christmas Eve into Christmas Day. Track of the low is now projected to be a little more to the west, so the heaviest rain may occur just offshore.

From an out and back run yesterday to “fossil point” via the Chumash Trail and Rocky Peak fire road. View is of Simi Valley, with Boney Mountain and Conejo Mountain in the distance.