Last year on this date, Southern California was in the middle of a heatwave. On June 20, 2008, Los Angeles Pierce College in Woodland Hills reached a record-setting high of 111°F, and on June 21 the temp reached 108°F!

Not so this June! So far this month, Downtown Los Angeles has not had a day when the average temperature was above normal. And it's not only the low elevation stations that have been cool. Several times this month the overnight low at the Big Pines RAWS, near Wrightwood in the San Gabriel Mountains, has dropped into the thirties, and daytime temps have averaged more than 10 degrees below normal.

This translates to great running weather in Southern California, and near perfect weather for trail running in the San Gabriel Mountains. Today, did the Three Points - Buckhorn loop, along with a short detour up to the summit of Waterman Mountain. The route worked out to about 23 miles with a reality-checked elevation gain/loss of about 3800'. Here's a Google Earth browser view of a GPS trace of the run.

The title photo is of Dave Burke, cruising down a nice section of the PCT between Cloudburst Summit and Cooper Canyon.

Related post: Three Points Loop Plus Mt. Waterman

Overnight the lows on the high peaks had dipped into the 30's, and today the high temps would be 15-20 degrees below normal. If I could have ordered the perfect mix of temperature, clouds and sun for running in the Angeles high country, it would be difficult to top the weather this weekend and last.

Now that Hwy 2 was open between Islip Saddle and Vincent Gap, and we could do a car shuttle, Miklos, Krisztina and I had decided to run from Inspiration Point to Islip Saddle on the PCT. Starting at Inspiration Point instead of Vincent Gap adds about 4.5 miles to the run, but the miles are relatively easy, and the stretch is a good warmup for the 2800 ft. climb up Mt. Baden-Powell.

Here's a Google Earth browser view of a GPS trace of our approximately 18 mile route. We wandered down the south ridge of Mt. Baden-Powell, so this is a little longer than the usual route. The elevation gain was about 3300 ft., with an elevation loss of about 4000 ft. Continuing over Mt. Williamson to Eagle's Roost would add about 4 miles and 1400 ft. of elevation gain.

Note: The speck in the summit photo is one of several violet-green swallows working lift and zooming along the top of southeast face.

Off to the south, I heard the distant rumble of thunder. The developing line of thunderstorms had swept through the West Valley about an hour before I began my run at Ahmanson Ranch.

Unusual weather for June. Not so much that there were thunderstorms, but that the thunderstorms were in part the result of an unseasonably strong jet embedded in the base of an upper level low.

It's a bit of a stretch, but an argument could be made that these storms were a calling card of an increasingly energetic atmosphere, and a developing El Niño.

Several factors point to an increased probability of El Niño conditions developing over the next few months. Among them, Equatorial Pacific SSTs have increased, and the subsurface heat content is the highest it's been since the El Niño of 2006-07.

But as the short-lived 2006-07 El Niño event demonstrates, an El Niño is more than just warm Pacific equatorial SSTs. Through complex forcing and feedback mechanisms, the atmosphere and oceans have to cooperate on a global scale. Generally speaking the atmosphere speeds up when there is an El Niño, and slows down during a La Nina.

And it looks like the atmosphere may be speeding up. Orbits of the Global Wind Oscillation, a measure of atmospheric momentum, have been shifting upward, in the direction of more energetic values usually associated with an El Niño.

But an El Niño is not a done deal. The climate system is just leaning in that direction. As climate scientist Klaus Wolter has pointed out, in a similar situation in 1973-1975, the climate fell back into a La Niña for another year. At this point it appears we may be diverging from that analog case. We'll see!

Update June 6, 2009. The April-May Multivariate ENSO Index (MEI) value, released today, has increased by 0.54 to +0.34. As discussed by MEI originator, Klaus Wolter, the 3-month rise of the MEI since January-February is the 4th highest on record for this time of year, exceeded only by the strong Niño of 1997. According to Dr. Wolter, if next month's MEI rank is at least the same as this month (37th), "it would be unprecedented for it to drop below that high-neutral ENSO-phase range by the end of 2009, virtually excluding a return to La Niña, based on the MEI record since 1950."

Related links: ENSO Diagnostic Discussion, ENSO Wrap-Up

So far, Brett's intro to Bay Area trail running had taken me to the Marin Headlands and Pt. Reyes National Seashore -- outstanding areas in which to run and hike, with great scenery, terrain and courses. An area that might be overlooked by a visiting trail runner is the Presidio. That's where we were running this morning.

Warm weather had chased the fog away. Saturday, the high temp at SFO was 89 degrees, and today the high was forecast to be in the 90s. So it wasn't a big surprise that at 7:30, the temp was already near 70 when we descended the stairs at Inspiration Point. (SFO would set a record high of 93 later in the day.)

Our loop started on the Ecology Trail and then worked down through the Main Post, under the 101, across Crissy Marsh, and onto the Golden Gate Promenade (Bay Trail). From the Promenade there were iconic views of San Francisco Bay, Alcatraz, Marin, and the Golden Gate Bridge. Just past the Warming Hut we turned up the East Battery Trail stairs, and then continued west, under the southern abutments of the bridge.

Here we followed the Coastal Trail past several 100+ year old defense batteries, to another nice overlook of the Golden Gate. After clambering up on one of the battlements, we headed east to Fort Scott and picked up the Bay Area Ridge Trail. This segment took us through the Presidio's trademark pine, cypress and eucalyptus forest to the high point of the course near Rob Hill Campground, then along the Presidio Golf Course, and finally down past Andy Goldsworthy’s cypress spire to the car. From the point of view of this out-of-towner, the course was spectacular, and it's hard to imagine an urban run with more variety!

Our particular loop worked out to about 5.5 miles, with an elevation gain/loss of about 450 ft. Here's a Presidio Trust map of Presidio Trails and Overlooks (PDF), a NPS Presidio Map, and a Google Earth browser view of a GPS trace of our loop.

I had a great time in San Francisco, and can't wait to get back and see more... Thanks Brett & Amanda!

Brrr... I picked up the pace -- even with long sleeves it was COLD on Rocky Peak Road. Another in a series of blustery April systems was stirring up the weather in Southern California. Thickening clouds spritzed rain, and a belligerent wind told me in laughing gusts that I could not run fast enough to stay warm.

Occasionally a patch of sun would find its way through the clouds, briefly warm and encouraging. I needed only  to think of the 100 degree days ahead to appreciate the chilly temps.

Another cool system is forecast to move through Southern California on Friday, bringing with it a chance of rain -- and more great running weather. Easter weekend should be spectacular!

Some related posts: Simi Valley from Rocky Peak, San Fernando Valley from Rocky Peak

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!

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.

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

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.

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

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.

Rocks and snow at the top of the Chumash Trail, near its junction with Rocky Peak fire road, in Rocky Peak Park.

From Thursday's run in the snow.

Our latest storm added another half inch of rain to our water year total in Los Angeles. This brings the water year rainfall total to 2.85 inches. This is 1.35 inches above normal for the date. As much as a foot of snow was reported in the Antelope Valley and the snow level dropped to near 2000 ft in the foothills and mountains of Ventura and Los Angeles counties.

What's next? Things should stay dry in Southern California until around Monday, when a fast moving front sweeps through the state. Later in the week, sometime around Christmas, the models are suggesting the possibility of a major system impacting California. We'll see!

The photograph of Oat Mountain was taken this morning on an out and back run on Rocky Peak fire road. The highest stretches of the fire road were covered with an icy layer of snow.

Related post: Chumash Trail Rocks & Snow