A 5000' deep marine layer produced some spectacular views along Angeles Crest Highway on the way to Islip Saddle this morning. The peak on the right just above the clouds is 5409-foot Monrovia Peak. Peaks of the Baldy group can be seen in the distance on the left.

The plants on the left with the red blossoms are scarlet bugler.

Even if landmarks didn't give away the southerly position of the sun, the leafless valley oak, green grass, and the dynamic nature of the clouds all say "Winter!"

From a run last week in Upper Las Virgenes Canyon Open Space Preserve, better known as Ahmanson Ranch.

Ladyface is the peak left of center. It's west of Kanan Rd. just south of the 101 Freeway. Sandstone Peak, the highest summit in the Santa Monica Mountains, is in the distance on the right.

From this evening's run on Lasky Mesa.

Some related posts: Ladyface Loop, Ladyface the Long Way, Sandstone Peak from Wendy Drive

According to the 1981-2010 climate normals January, February and March are the rainiest three months at Downtown Los Angeles (USC). March is normally a little wetter than December, but close enough that the four months December to March "normally" account for nearly 80% of Los Angeles' annual rainfall total of 14.93 inches.

But normal weather years only exist on paper, and those rarely seen monthly normals are just a reference so we may make comparisons from year to year. This water year Downtown Los Angeles was only about 0.2 inch under the normal amount of rainfall for December, but as of today is about 1.5 inches under the normal January total. When you add it all up Los Angeles is at about 63% of the normal total for the water year.

Although much of Southern California has recorded well below average rainfall, that isn't necessarily the case across the board. LAX's water year rainfall total currently stands at 89% of normal, and Santa Barbara Airport is at 94% of normal.

There are some indications (GWO phase and forecast MJO activity) that February might just have its share of wet weather. We'll see!

Update February 13, 2013. Despite hopeful signs at the end of January and CPC's above average Precipitation Outlook for Southern California for the period February 5-9 and February 7-13, Downtown Los Angeles (USC) has recorded only 0.02 inch of rain so far this February. Los Angeles water year rainfall now stands at 4.42 inches, which is slightly less than half of normal. Once again it looks like there may be some opportunities for wet weather in California during the last week or so of February, but the increasingly La Nina-like character of the atmospheric circulation suggests more rain is probable in Northern and Central California than in the southern part of the state. Again, we'll see!

The photo of clouds and showers in the Los Angeles basin is from this morning's run in the Santa Monica Mountains.

More miles means more sunset miles.

From a longer than expected run Monday afternoon.

From this morning's run of the Garapito loop from Marvin Braude Mulholland Gateway Park at the southern end of Reseda Blvd.

Some related posts: Ferns Along the Garapito Trail, Garapito Trail Runs

Sunday, running in the rain on Rocky Peak, it occurred to me that I'd done a lot of runs on rainy days this Fall.

When I got back from the run I checked the NWS web site and found that during the months of October, November and December there have been 17 days with measurable rain at Downtown Los Angeles. Normal for that period (to date) would be around 9 days.

The thing is, we've yet to have a day with a half-inch or more of rain Downtown, and we're only at about 60% of normal rainfall for the water year.

At the moment it looks like another weak system passes through tomorrow afternoon and evening, followed by somewhat wetter systems Sunday night and Wednesday.

At times both the GFS and ECMWF have been forecasting a stronger system might impact Southern California near the end of the year. Today the GFS has it in our forecast and ECMWF doesn't. The culprit in the ECMWF forecast is a cutoff upper level low, so look for the forecast to change!

The photograph of the cumulus buildups (north of Los Angeles) is from a run at Ahmanson Ranch on December 13, following the passage of a cold front.

The crest of the Santa Monica Mountains east of Castro Peak stands out in bold relief above a tumultuous ocean of low clouds and fog.

From this morning's run of the Bulldog loop in Malibu Creek State Park.

Some related posts: Bulldog Loop or Saddle Peak Out & Back?, Malibu Creek State Park Scenic Loop

Although we didn't have the deluge they experienced in Central and Northern California, Southern California did get some rain. From Tuesday night (11/27) to Monday morning (12/3) Downtown Los Angeles (USC) recorded 1.03 inches, bringing the water year total to 1.36 inches. As of today that's 1.08 inch below normal.

Some foothill and mountain stations were able to wring out much more rain from the moist tropical flow. Opids Camp recorded 3.02 inches, White Ledge Peak 4.09 inches, Refugio Pass 4.61 inches, and Rocky Butte 8.51 inches. For some storm totals from up north and more info about the "atmospheric rivers" that relayed the moisture up from the tropics, see my December 8 post on Southern California Weather Notes.

The photo above was taken between "storms" early Sunday morning, December 2, on a run in Topanga State Park. It started to rain shortly after I finished the run.

It looks like we might get a little more rain this next week, with a chance of rain on Wednesday and then maybe again on the weekend. We'll see!

The marine layer spills over the crest of the Santa Monica Mountains between Saddle Peak and Malibu Canyon.

From this evening's run on the Phantom Trail and other trails in Malibu Creek State Park.

Related post: Saddle Peak from the Phantom Trail

An alternative rendition of an image posted in November 2007. Did this version in 2007, but didn't post it at the time. A Photoshop filter was not used.

Thunderstorms rumbled across the eastern and northern San Fernando Valley and San Gabriel Mountains while I was running up to Castle Peak yesterday afternoon.

In this case the Edison Road is in Upper Las Virgenes Canyon Open Space Preserve.

From this morning's run of the Upper Las Virgenes Canyon - Cheeseboro Ridge Loop. This Park Service PDF includes a map of the area, and this interactive Google Earth browser view shows the route.

Spotted these unusual clouds while running in Upper Las Virgenes Canyon Open Space Preserve today. Better known as Ahmanson Ranch, the open space area is on the western margin of the San Fernando Valley, northwest of Los Angeles.

The clouds were strikingly similar to clouds I'd photographed last January following the development and dissipation of a band of mid-level mammatus clouds over the San Fernando Valley. As before, the clouds were round-bottomed and were ragged with virga.

Upper air charts and model analyses indicated the clouds were at an altitude of about 20K-25K, and were associated with a very small scale upper level disturbance.

Here's a wider view of the clouds.

Related post: Mammatus Clouds Over the San Fernando Valley, More posts...

These unusual clouds are a complex of lenticular clouds to the north-northeast of Mt. Pinos, photographed this morning from near Mt. Abel. They were produced by strong south-southwesterly winds blowing across the east-west oriented Emigdio and Tehachapi mountain ranges, north of Los Angeles. Here's another view of these clouds from near the summit of Mt. Pinos.

The winds were associated with the circulation of an unseasonably strong low pressure system off the California coast. The storm system has resulted in measurable rain as far south as Santa Barbara County, and new rainfall records for the date were set in San Francisco, Paso Robles and Santa Maria.

The photographs were taken during a blustery out and back trail run from Mt. Pinos to Mt. Abel on the Vincent Tumamait Trail in the Chumash Wilderness. At the start of the run, the temperature at the Chula Vista trailhead (8400') on Mt. Pinos was a chilly 39°F. In exposed areas the wind speed was 20-25 mph with gusts to around 50 mph.

Other than the potential for deadfall, the wind wasn't too bad in the trees. The Vincent Tumamait Trail was in the best condition I've seen in years.

Update June 6, 2011. The low that was off the Central California coast Saturday and most of Sunday and an associated cold front set a new rainfall record for June 5 at Santa Barbara Airport, and produced a few sprinkles and showers in the Los Angeles area.

Some related posts: Mountain Weather, Lenticular Wave Clouds, Mt. Pinos - Mt. Abel Out & Back

Last Sunday started with light rain in western Los Angeles County, and on the drive to the San Gabriel Mountains, I wondered if the Three Points trailhead would be above the mile deep cloud layer. It was, but barely so, and at the start of the run a couple of scuddy clouds hung over the parking lot.

These were soon left behind, and while the lowlands dealt with damp, dreary weather, my Easter morning run on the PCT continued toward Cloudburst Summit under a bright sun and mostly cloudless skies.

I encountered my first patch of snow a little past Camp Glenwood, on a shaded north-facing slope at about 6300', nearly three miles into the run. With the above average snowpack, it would have been a surprise not to find some patchy lower elevation snow. Much more snow could be seen on the higher elevation slopes, and the big question was: how much snow would there be on the Mt. Waterman trail?

From Cloudburst Summit I continued eastward on the PCT to Cooper Canyon -- one of the most idyllic places in the San Gabriel Mountains. Snowmelt had increased the streamflow, and to start the climb to Buckhorn, two creek crossings were required. It was cool enough that if I could avoid it, I didn't want to soak my shoes. On the other hand I would rather have wet shoes, than fall bodily into a creek trying to keep them dry. A makeshift trekking pole helped prevent either scenario. Cooper Canyon Falls was spectacular.

On a Summer day this route can be quite warm, and I usually top off my Camelbak at Buckhorn Campground. Good thing it was a cool day -- Buckhorn Campground was closed and the water in the campground was turned off. It looked like the Forest Service was doing a major revamp of the campground.

From the campground I still couldn't tell if the Mt. Waterman trail was going to go. There was a lot of snow on the north-facing slopes, but I was betting it wasn't going to be as choked with snow as it looked. Worst case, I could turn around, so I decided to continue until there was some reason not to.

There was some snow, and at one point I left the trail to avoid a particularly steep snow slope. About a mile from Hwy 2, the trail worked up onto a broad east-facing ridge, and from that point the trail was mostly free of snow.

No sooner had the snow issue been resolved, when clouds began to spill over the ridges and increase overhead. I knew -- or at least thought I knew -- that other than decreasing the visibility and temperature, these clouds shouldn't be a problem. Even so, I was very glad to know the terrain and route well, and have some additional gear in my pack.

The title photograph is from the upper section of the Mt. Waterman trail. The clouds are in the deep canyon between east ridge of Waterman Mountain (8038') and Twin Peaks (7761').

Some related posts: Cooper Canyon Cascade & Falls, Manzanita Morning

Follow the wind,
Run to the sky.
Find what you're searching for,
Near or far.

Even in Southern California, Spring can be a fitful beast. This afternoon the temperature was in the low 50s, and the wind was blowing hard enough it was difficult to take a photograph. Just one week ago it had been a stifling 95 degrees -- a temperature swing of more than 40 degrees.

Orographic Lift, Waves, and Turbulence over the San Jacinto Mountain Range

After last Sunday's record-setting storm in Southern California, and the cool, unsettled weather during the week, we expected snow conditions on Mt. San Jacinto to be even better than on previous trips this March. But snow conditions -- especially backcountry snow conditions -- aren't always what you expect. The new snow, maybe a foot of it, was as thick as wet concrete. If we'd had a little kiwi fruit flavoring, it would have been perfect for shave ice.

Even if the snow wasn't what we had hoped for, the day was extraordinary. Another weak front was moving into Southern California and the strong onshore flow ahead of the front was creating several kinds of interesting mountain weather phenomena -- some common and some not so common.

Riding up the tram, we could see plumes of dust blowing across the desert floor east of Banning Pass, and a stack of lenticular clouds hovered over the mountains east of San Gorgonio Mountain. It was breezy at the upper tram station, and from the walkway descending to Long Valley, we could see rimed trees on the southeast side of San Jacinto Peak.

We skied up a beautiful untracked drainage south of the Round Valley trail, and eventually worked our way over to Long Valley Creek and then to Tamarack Valley. We were almost to the top of the steep step above Tamarack Valley, and had paused for a moment to look around. There was a distinctive wave cloud to the southeast, and the lower cloud deck was beginning to engulf Toro Peak (8716'). I turned to continue up the slope, and as I looked up, the first of a series of tumbling and twining filaments of gossamer cloud swept past in the turbulent west-northwest flow (video).

Six months ago, also before the passage of a cold front, I'd seen similar clouds on Boney Mountain, in the Santa Monica Mountains. In that case and here on San Jacinto, a moist layer in a stably stratified westerly flow was being lifted over a mountain range. Depending on whether the flow remained laminar, or became transitional or turbulent; a wave cloud, transient wave cloud, or these turbulent thin sheets of cloud might form. In each case the atmosphere was becoming more moist and the clouds were precursors to the formation of a more widespread and persistent cloud layer.

These vaporous, turbulence-induced clouds bear a striking resemblance to interstellar molecular clouds. Both appear to occur in a high-Reynolds-number regime, and each appears to consist of a cohesive, thin sheet of condensate that can be stretched, sheared, undulated and torn. As in the case of its interstellar counterpart, when viewed edgewise, the clouds look like they are comprised of thin, web-like filaments.

The title photo was taken a little below the summit, after ascending the peak. It's a view to the south, past Jean Peak (10,670') and Marion Mountain (10,362'), and shows the terrain induced uplift, waves, and turbulence over the San Jacinto mountain range. The flow is from the right to left.

The long streaks in the photograph above are cirrus clouds embedded in a 125 kt jet stream that was positioned over Southern California Thursday afternoon.

The jet stream was at an altitude of about 30,000 ft. and associated with an upper level low pressure trough off the coast. This trough is the source of the disturbances that are resulting in our latest bout of wet weather.

The jet stream is a key feature of the earth's atmospheric circulation, and plays an important role in both weather and climate.

For more about jet stream cirrus see A Composite and Microphysical Study of Jet Stream Cirrus Over the ARM Site.

The photographs are from a trail run on Thursday.

View of Eagle Rock from East Topanga Fire Road, a little west of its junction with the Garapito Trail

From Sunday's run to Trippet Ranch.

By the time I reached Rancho Sierra Vista/Satwiwa at the end of last Sunday's wet run to Serrano Valley and back, the frontal band was mostly done with its showers and was speeding to the east. In its wake were blustery winds, broken clouds, and a dynamic patchwork of sun and shadow on Satwiwa's spectacularly green landscape.

These mountain wave clouds were produced by north-northeast winds blowing across the generally east-west oriented mountain ranges north and northwest of Los Angeles. The clouds form near the crests of the undulating airflow downwind of the mountains.

The cirrus veils trailing downwind from the clouds are comprised of ice crystals. There was little shear, so the wisps and sheets of cirrus are aligned with the wind and perpendicular to the long axis of the cloud. Compare to the cirrus veil of these lenticular clouds, also formed by north-northeast winds, but which were being sheared by northwesterly winds.

From a trail run at Ahmanson Ranch on Thursday.

These rare clouds -- a mid-level form of mammatus -- were over the western San Fernando Valley last Thursday afternoon, January 6, 2011. They were produced by the moisture and dynamics associated with a closed upper level low that was about 390 miles WSW of Los Angeles, and moving ENE at about 17 mph.

I first noticed the mammatus clouds around 3:30 p.m. About 30 minutes later, when I started my trail run in the Simi Hills, the cloud band had shifted a couple of miles to the WNW, but the mammatus was still present. The title photograph was taken just a few minutes into the run, at about 4:07. This uncropped version of the image shows the clouds in relation to the terrain.

The mammatus was in the leading band of a series of cloud bands slowly moving from the ESE to the WNW. Over the next 30 minutes the mammatus mostly dissipated, as the cloud band became disrupted by shear. During this period the bands evolved into a wave-like sequence of bulbous clouds that had some of the characteristics of mammatus, but were not multi-lobed. The bases of these clouds were ragged -- an indication that snow showers were sublimating in the dry air below. The photograph of the cloud sequence was taken at about 4:37 p.m. Some remnants of mammatus could still be seen in the sheared leading band.

The circumstances in which mammatus is observed and some possible mechanisms for its formation are discussed in the 2006 paper, The Mysteries of Mammatus Clouds: Observations and Formation Mechanisms by David M. Schultz, et al.

Based on a NAM analysis for Van Nuys and NKX (San Diego, CA) sounding, the atmospheric profile was consistent with real-time soundings when mammatus is present. A BUFKIT model sounding based on NAM data for 4:00 p.m., shows a moist layer from about 14,000 ft. to 23,000 ft., with a dry subcloud layer. The freezing level was indicated at about 8500 ft. A plot of vorticity from NAM data indicated a vorticity lobe in the area at the time the clouds were observed. As can be seen in both photographs, there was also strong shear between 20,000 ft. and 25,000 ft. A superadiabatic subcloud layer is not present in the soundings, but cooling from subcloud evaporation or sublimation might create one.

The photograph in the post Simi Hills to the San Gabriel Mountains was also taken on this trail run.

From this evening's run at Ahmanson Ranch.

Foretelling the approach of a system forecast to bring wet weather to some areas north of Pt. Conception New Year's Day, and Los Angeles Sunday, this thick cirrus cloud shield is associated with the circulation around a low a few hundred miles off the Pacific Northwest coast.

Wednesday's cold front, the latest in a series of surprisingly frequent December weather systems, increased the water year rainfall total at Downtown Los Angeles (USC) to 11.70 inches. As of today, L.A.'s rainfall total is about 8 inches above normal, and more than three times the normal amount of rainfall for the water year to date. For the first six months of the 2010-11 water year, the rainfall total for Downtown Los Angeles is the fourth wettest in the 133 years that records have been kept. The water year starts on July 1 and ends June 30.

The photograph is from today's run on the Chumash Trail and Rocky Peak Road, northwest of Los Angeles. It was cold on the north facing sections of trail that don't see the sun this time of year. Inch long needle ice crystals had formed along the margins of the trail in several places.

From a short run at Sage Ranch Christmas Day.

Twilight view of the San Fernando Valley from yesterday's run near Castle Peak.

Related post: Castle Peak

The view is northwest from Rocky Peak road in Rocky Peak Park. In the distance is Marr Ranch Open Space, Tapo Canyon Regional Park, and Whiteface Open Space. The Ventura Mountains are shrouded in clouds.

From today's out and back run from Chatsworth Oaks Park, near Chatsworth Reservoir, to "fossil point" on Rocky Peak road.

The temperature was in the low fifties, but with a 20 mph wind it was cold. I had just run up the Chumash trail, and was on my way down. The sun was nearing the horizon and hidden by a band of clouds. It had been like that since I topped out at Rocky Peak road. I hoped by the time I reached a vantage point of Chumash Rocks the setting sun would break underneath the clouds and illuminate the formation.

Nope. When I reached the viewpoint, the rocks were still in shadow. And the wind was even stronger. Squeezed between two hills, it rushed through the little col in cold, turbulent gusts. Buffeted by the wind, and chilled to the bone, I waited for the sun.

And waited. It was too cold to just stand there. I took a few photos, but the sun and clouds were not cooperating. At some point, minutes away, the sun would set, and that would be that. The photo just wasn't going to happen. I returned to the trail and began to run down the hill.

In the lee of the hills the wind lessened, and it was not so cold. It was still a few minutes before sunset, and as I rounded a corner I could see a bright glow at the edge of the clouds.

I was several hundred yards down the trail when the first hint of sunlight appeared on a distant hill. It was veiled and muted, but it was sun. Maybe there was time. I turned and hurried back up the trail.

Hot on the heels of our record setting Autumn heatwave, an upper level low off the coast has been spinning subtropical moisture into Southern California. The unstable weather has produced some impressive clouds, isolated showers, strong thunderstorms, as well as a few rainbows. This thunderstorm development is north of Los Angeles.

From today's run in the Simi Hills.

The clouds are in the Conejo Valley and the crags are a prominent highpoint on the ridge that tops the west face of Boney Mountain. Here's a Google Earth aerial view SSE along the ridge that shows the topography. From the upper cliffs the west face drops over 2000' to the Backbone Trail in Blue Canyon.

Ascending the western ridge, or easier eastern ridge, is an adventurous way to access the Backbone Trail from Wendy Dr. Once over Tri-Peaks and on the Backbone Trail several loop variations are possible. These range from a relatively direct return on the Boney Trail, to lengthy excursions to Serrano Valley or La Jolla Valley.

Today's variation worked out to about 20 miles. Once on the upper section of the Backbone Trail, I followed it west down the Chamberlain, Boney and Blue Canyon trails to the Danielson Multi-use area in Sycamore Canyon. After doing a circuit in Sycamore Canyon I picked up the Upper Sycamore Trail and headed back to Danielson Road, Satwiwa, and the trailhead at Wendy Drive.

Some related posts: Boney Mountain Western Ridge & Loop, Sandstone Peak from Wendy Drive, Boney Mountain North Side Loop

Because of their unusual "flying saucer" appearance, lens shaped lenticular clouds have long drawn attention. According to a research article in Weather, depictions of wave clouds appear in Gothic art from the 15th century.

Lenticular clouds typically form when wind flows into, and then up and over a mountain range, creating a series of "roller coaster" atmospheric waves downwind of the range. Lenticular clouds can (but don't always) form in the peaks of the waves, as a layer of air rides up a wave, and cools and condenses. The waves are called standing waves because the peaks and troughs can stay (more or less) in the same place for hours at a time.

The rising air on the windward side of a lee wave can be soared by gliders to high altitudes. According to the FAI, the current world absolute altitude record for gliders is 15,460 meters (50,722 ft.). This record was set by the late Steve Fossett in 2006, soaring a mountain wave in the Andes. Mountain wave soaring was pioneered on the east side of the Sierra, and several single place sailplane world altitude records have been set soaring the Sierra wave.

Lee waves also have a nefarious side. Rotors, breaking waves, and other phenomena associated with mountain waves can create extreme turbulence. A sailplane destroyed in early research on rotors was estimated to have experienced 16 g of acceleration. According to the Australian Transport Safety Bureau, "clear air turbulence associated with a mountain wave ripped apart a BOAC Boeing 707 while it flew near Mt. Fuji in Japan. In 1968, a Fairchild F-27B lost parts of its wings and empennage, and in 1992 a Douglas DC-8 lost an engine and wingtip in mountain wave encounters."

The wave clouds above were photographed northwest of Los Angeles during a trail run earlier this month. The wind forming the wave clouds appears to be from the north-northeast. The situation was peculiar because the wind at nearly all levels at that time was from the northwest. The tops of the wave clouds are being sheared by winds blowing from the northwest (left to right).

Here's an animated series of NRL satellite photos showing the waves pictured above, and the complex wind and wave pattern at the time of the photograph.

Pushed up and over Boney Mountain's two thousand foot western escarpment, Pacific winds condense into thick cloud along its jagged crest. At times breaking free of the mountain's grasp, patches of cloud drift eastward, creating a patchwork of sun and shadow on the steep slopes, and in the valley below.

In the distance, the Ventura Mountains gleam with a mix of snow and cloud, and below the fields of Satwiwa stand out vibrant and green. At my feet hundreds of purple shooting stars dance in the wind; and nearby yesterday's rain seeps and trickles from moss to lichen on the scraggy volcanic rock.

It is a remarkable morning, and an exceptional one to be doing the Boney Mountain north side loop. Here's a short HD video of some of the views along the way. (If the video doesn't play cleanly the first time through because of bandwidth issues, let it finish and then try playing it a second time.)

From this evening's run on the Hummingbird Trail in Simi Valley, California.

There's snow in just about every mountain range of Southern California following last week's series of storms. This subdued sunset view is of the Simi Valley and the Topatopa Mountains.

From this evening's run in the Simi Hills.

Computer models and other tools continue to forecast a shift to an "El Nino like" upper flow pattern next week that could result in an extended period of wet weather in Southern California. I'll be updating Southern California Weather Notes on Wednesday with additional info.

The photograph of patterned altocumulus clouds is from this afternoon's trail run along the northern boundary of Ahmanson Ranch, near Los Angeles.

Got caught in some showers this afternoon on Rocky Peak, returning from a rambling trail run from the San Fernando Valley over into Simi Valley.

This was one of those "not sure where I'm going" runs that unfolded as it progressed. It started near Chatsworth Reservoir at Chatsworth Oaks Park, worked over to Santa Susana State Historic Park, then up the Old Stagecoach Road. At the top of the old Stagecoach Road, I picked up the Upper Stagecoach Trail and followed that to Santa Susana Pass and the 118 Frwy. From there it was a short distance down the west side of Santa Susana Pass Rd. to the Lower Stagecoach Trail, which took me to Corriganville.

Once down in Simi Valley there are four trails that ascend to Rocky Peak road, and my return route. From the shortest to the longest, they are the Wildlife Corridor trail, Hummingbird Trail, Chumash Trail and the Marrland/Las Llajas trail. Not sure how long it would take to get back to the SFV, I finally decided on the Chumash Trail.

Running up the Chumash Trail, the wind picked up, the clouds began to lower and thicken, and the temperature dropped. Minutes after turning right onto Rocky Peak road the showers began, and it wasn't long before the sleeves came out of the pack.

The return trip, with a net elevation loss, went a little quicker than expected. Next time I'll have to give the Las Llajas option a try. That would extend the run from about 17 miles, to something over 20. The approximate elevation gain/loss on the 17 mile version was a little under 3000 ft.

Related post: Old Santa Susana Stage Road

Some outstanding evening runs this week. Did a FiveFingers run out at Ahmanson on Tuesday, and as sometimes happens this time of year, didn't make it back before dark. Was up on Lasky Mesa in the fading light, with endorphins at full flow. In a distant grove oaks I could hear a Great Horned Owl, and with each hoot-whoo it seemed the zeal of the day was turning to the tranquility of the night. The running was effortless and ethereal.

This evening's run was also superb. Over the course of the run, the skies had become increasingly gray and troubled, as a weak cold front approached the area. Climbing a long hill, the light was dank, and I had given up on the sun. But as I neared the crest of the hill, orange-red sunlight began to illuminate the clouds from below, highlighting a sunset shower. Large, cold rain drops began to patter around me, and I watched mesmerized, as the light, clouds, and rain played on the sky.

Like flies on the sky, contrails are visually annoying, but do they also affect climate? For a discussion of the possible effects of these artificial clouds, see NOVA's Dimming the Sun: The Contrail Effect by Peter Tyson.

From today's run in the Simi Hills, northwest of Los Angeles.

Who would think a western Pacific typhoon could so directly affect California's weather? But that's what is happening. The moisture from typhoon Melor, which was over Japan just a few days ago, was captured by an extending and strengthening jet stream. This has resulted in an atmospheric river of moisture, stretching across the Pacific and into California.

This morning, Intellicast composite radar shows Northern and Central California already being hammered by the system. Southern California has seen a few showers, and several stations have already recorded significant rainfall. As of 9:00 a.m. the CNRFC Precipitation Map shows isolated 24 hr. rainfall amounts in the foothills and mountains of Santa Barbara, Ventura, and Los Angeles County ranging from about 0.16 inch at Sandberg to 0.61 inch at West Big Pine.

The last day there was measurable rainfall at Downtown Los Angeles (USC) was on June 5, 2009, when 0.13 inch was recorded. Computer weather models forecast the best dynamics and highest rainfall totals will be in the northern two-thirds of the state, but in recent days have been trending wetter in the Los Angeles area, particularly in the mountains.

With so much moisture in the atmosphere, it takes very little lift to produce rain. Onshore winds, full of moisture, are lifted by foothills and mountains across the flow, and the result is rain -- sometimes lots of it. In this case it appears the south to west facing mountains and foothills of Santa Barbara, Ventura and Los Angeles counties may record much higher rainfall totals than the lowland areas.

In a decade characterized by unusual El Ninos, the ongoing El Niño of 2009-2010 is another strange one. El Niño signals continue mixed. The Aug-Sep Multivariate ENSO Index (MEI), decreased from 0.978 to 0.754, however other El Niño signals appear to be rebounding. In the last two weeks low level equatorial westerly anomalies have increased significantly. The reduction in the strength of the trade winds, and a downwelling Kelvin wave resulting from a very strong westerly wind burst already appear to be increasing upper ocean heat content in the central equatorial Pacific. The 30 day moving Southern Oscillation Index (SOI) has been dropping, and should return to negative territory in a day or so.

Recurring equatorial westerly wind bursts and enhanced west-central Pacific convection has been slowly migrating eastward. The most recent round of enhanced convection was centered at about 160E. This is consistent with a developing El Niño, and may have contributed to the creation of the atmospheric river now affecting California, by helping to extend the Pacific jet stream following an East Asian mountain torque event.

However, total and relative AAM remain negative, and are lower than is generally the case during a developing El Niño. Of the weak to moderate El Ninos that have occurred Since 1959, only the 1977-78 and 1994-95 El Niños have had negative average July-September relative AAM values comparable to the current El Niño. Since 1959, only 4 of 15 El Niños have had negative average relative AAM values during the Southern California rain season of November to March. (Revised 12/14/09)

Moderate El Niños come in many flavors and have varying impacts. Under the guise of such El Niños Los Angeles experienced its second wettest water year on record in 2004-2005, when 37.25 inches of rain was recorded; then in 2006-2007 had its driest water year on record, when only 3.21" was recorded. What flavor will the 2009-2010 El Niño be?

The photo of the tree and clouds is from yesterday's run at Ahmanson Ranch.

Related post: How Does the El Nino of 2009-10 Compare to Other Warm ENSO Episodes Since 1950?

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.

One, two, ten...
Will the switchbacks ever end?

I can't think of a tougher stretch of trail in the San Gabriel Mountains. From Mt. Baldy Village, the Bear Canyon/Old Mt. Baldy Trail climbs 5800' in 6.7 miles to the 10,064' summit of Mt. Baldy (Mt. San Antonio). The route is as rewarding as it is difficult, with inspiring views and interesting terrain.

I had hoped for some remnant clouds from Friday's storms, but didn't expect to be using my windshield wipers driving to the trailhead. The dark gray clouds piled against the mountains had a scuddy, stormy look, and I had a difficult time convincing myself that it was just a deep marine layer. But the sun was shining when I parked at the bottom of Bear Canyon Rd. and began to walk up the steep, cabin-lined street.

The last time I had been on the trail was July 2004, during the Baldy Peaks 50K. That day we started at the parking lot at Icehouse Canyon, and over the course of the race climbed Mt. Baldy twice. The first time from the Village, and the second time from Manker Flats. Today I wasn't in a race, and would be completely satisfied to climb Mt. Baldy just once.

Running up a moderate section of trail below Bear Flat, I tried to figure out the last time I had run down the Bear Canyon Trail. Sometime before the Baldy Peaks race. I wasn't sure how long it had been, but long enough to forget how grueling steep downhill can be.

My thoughts are interrupted by a pair of hikers coming down the trail. I ask how they're doing, and am surprised to hear, "not so good." They look disappointed and tired, and anxious to get down to the car. I wonder if one of them is ill, or if they just underestimated the difficulty of the trail.

A half-mile later I'm crossing the creek at Bear Flat (~5500'). This is where the fun begins. Here the trail switchbacks up a steep east-southeast facing chaparral slope to Mt. Baldy's South Ridge, gaining about 1500' in one mile. On a warm day it can be hellish. On a cool day it isn't easy. Today it is cool. The cloud layer has continued to crawl up the mountain, and it envelops me as I start up the switchbacks.

A little more than a year ago, these slopes were burned in the 2008 Bighorn Fire. I had expected to see black, burned and barren chaparral in the initial stage of recovery, but instead there is substantial growth, comparable to 2-3 years of recovery in chaparral at a lower elevation.

At an elevation of about 7000', I climb out of the clouds and into the sun. What a day! Benign clouds lap at the mountainside, enhancing already dramatic views. Between 7000' and 9000', I encounter several hikers and briefly chat with one veteran hiker, who tells me this is his friend's intro to hiking! It is a busy day for this trail, and I'm guessing I'll see more hikers when I descend.

Above 9000' the open forest of Jeffrey, Sugar and Lodgepole pine becomes more sparse and stunted. The route feels more alpine and climbs onto the rocky crest of an exposed ridge (HD Video Snapshot). A little higher, a large patch of snow accentuates the "you're getting near tree line" feeling.

Approaching Baldy's summit, I'm surprised to see a wispy cloud had also ascended the peak and is waiting for me to catch up. On top there seems to be a mix of young and old, veterans and first-timers, excitement and exhaustion. After a few minutes on the summit, I run over to West Baldy. Then it is gravity's turn, and I take the first steps down the slope.

The descent is just as extraordinary as the ascent, with far-reaching mountain views over a sea of clouds. On an exposed section of the ridge at about the 8500' I happen on a Sugar pine with a spiral scar from a lightning strike. Such trees are disturbingly common. There is a Jeffrey pine at about the same elevation on Mt. Baldy's North Backbone Trail with a similar lightning scar.

At around 7500', I descend into the clouds. The change from blue to gray does not carry with it the usual malaise. Wisps of warm cloud thread softly through the pines and a solitary deer walks silently through the dream-like scene (HD Video Snapshot).

One, two, ten... Will the switchbacks ever end? Finally, through the trees I see the brilliant green of the ferns at Bear Flat. Running becomes easier. I pick up the pace, and in a few minutes turn onto the asphalt of Bear Canyon road.

Here's a Google Earth browser view of a GPS trace of my route.

Some related posts: Mt. Baldy Runner, Lightning Tree

I glanced at my watch -- 5.25 miles. Clouds and fog had kept temps on the cool side for more than three-quarters of the Bulldog climb, but the sun was finally breaking through. Even though temps were down a few degrees, the long climb had still been grueling. The runner next to me was breathing heavily, and I mentally repeated my Bulldog mantra -- don't redline, don't redline.

For many of us, that's the problem with Bulldog -- some of it is runnable and some of it isn't. For the moment I was running, but I knew the grade well, and just ahead the fire road switchbacked right, and steepened.

I've been over the "I can run this hill no matter what" thing for a long time. For me, and the majority of trail runners, walking the steeps is a good thing. The little bit of time lost by walking is generally made up -- and more -- on other sections of the course.

Rounding a corner, the grade did steepen, and I slowed and started to walk. Taking advantage of the slow pace, I ate a Gu, took a Salt Stick cap, and gulped down some Gatorade. Another runner and I had been swapping leads up the hill, and he passed me -- again. As he increased his lead, I wondered if I should be pushing a little harder.

A left turn never felt so good! A few minutes before I had reached the top of Bulldog grade, and the highest point on the course. Now gravity was on my side, and I was enjoying the downhill. There were more challenges ahead, but for now I was lost in the moment -- savoring the wind in my face, the far reaching views along the rocky crest, and that wonderful feeling of being a runner.

Here's a Google Earth browser view of a GPS trace of the 22K course with my half-mile splits. (Generated in SportTracks.) See the XTERRA Malibu Creek Challenge web site for race results and additional info.

Some related posts: Malibu Creek State Park Shadow & Sun, Fog Along Malibu Creek, Bulldog Loop and the Corral Fire, Rock Formations Along the Backbone Trail

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

After a nostalgic hike to the bottom of Switzer Falls, drove to Islip Saddle to check out the snow conditions. Clouds ahead of Sunday's storm prompted a short run along Kratka Ridge to photograph some of the stunted sugar pines. Here's the unaltered version of the title image.

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

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.

Clearing clouds, northwest of Los Angeles, following the passage of an upper low storm system that resulted in widespread rainfall in Southern California. Several rainfall records for November 26 were broken in Los Angeles County.

Update 12/5/08 P.M. High amplitude flow continues to wreak havoc with forecasts. Our on-again, off-again chance of a shower this weekend might be on again. Original cut-off upper low center is still well offshore, but another low center has developed on the downstream side of high amplitude ridge, and this one is much closer to the Southern California coast. The low appears to be entraining some moisture, and could produce some showers, particularly as the low moves onshore and is absorbed in the main flow. We'll see!

Update 12/5/08 A.M. No rain is expected in SoCal this weekend... The cut-off upper low set up much further west than suggested by models Tuesday and now is spinning out in the eastern Pacific, nearly halfway to Hawaii. At the moment, it looks like it could be mid-month before our next chance for significant rain.

Update 12/2/08. Computer models have been having a tough time with both the short and medium term forecasts for Southern California. Recent runs have been hinting at the possibility of some rain Saturday or Sunday. This would depend on the strength, position and behavior of an upper low that is forecast to form off the Southern California coast Thursday.

From a run at Sage Ranch Park, near Simi Valley, California.