rain – Geoff Fox: My Permanent Record

They Love The Rain

There are some things I’m just going to have to get used to. I have never seen so many people happy about a rainy day! Really, people are ecstatic.

We didn’t get much. The rain started falling before dawn and was gone around 3:00 PM. Most areas got between an eighth and quarter inch–aka, very little. However, in a place that’s only gotten around two inches total since January 2014, even an eighth inch is a notable achievement.

For the next few weeks there will be a little green on the mountainsides. Desert flowers will quickly bloom, then die away.

It’s likely there’ll be no more rain until late fall. Climatically that’s the way it works.

Recent forecasts, first from the Aussies and now from the European Center for Medium Range Weather Forecasting, says a strong El Nino is building. If true, next winter in SoCal should be wet. We can really use it.

I wonder how many rain days we need before desert residents stop finding it cool? I’ll report back.

A Definite Maybe

Since last Wednesday I’ve been talking about the chance of the Palm Springs area getting a few sprinkles this Thursday. In most places caring about an iffy forecast for a tiny event so far in advance would be a non-starter. Not so in the desert where long time residents look forward to our few cloudy days!

So, here we are Monday. This is the sixth day since rain was first mentioned. I’m barely closer to knowing than I was then!

First, an admission. Without supercomputers no one could attempt a seven or eight day forecast. The atmosphere’s just too complex. But computer’s have shortcomings. I use the GFS model this far out.

The entire globe is covered by the GFS at a base horizontal resolution of 18 miles (28 kilometers) between grid points, which is used by the operational forecasters who predict weather out to 16 days in the future. Horizontal resolution drops to 44 miles (70 kilometers) between grid point for forecasts between one week and two weeks.

One point every 18 miles! At that resolution mountains disappear. Everything becomes a coarse approximation.

Later today Thursday will be seen in the much higher resolution CANSAC (California and Nevada Smoke and Air Committee) WRF model. CANSAC’s WRF only sees out 72 hours, but with 2km (1.2 mile) resolution.

For the geekiest reading, here’s the hardware CANSAC uses to run the WRF.

The CANSAC WRF real-time forecast system is operated on an SGI® ICE 8200 high-performance computer. Specifications are:

256 cores (Intel Xeon X5570)
384 GB RAM memory
20 TB disk space.

In the interim lots of human expertise is needed. The mountains west of the Coachella Valley are critically important. The models might not resolve them well, but I have to. They are a major reason we see less than six inches of rain in an average year (just over two inches since this year’s ‘wet’ season began in October).

I said Wednesday the coast was much more likely to see rain than Palm Springs. That still holds true.

If we get anything it will be tiny. In the desert that’s enough to perk ears.

Rain’s A Big Deal Here

We do a seven day forecast at KMIR. Yesterday I mentioned Day Eight. It got a shout out (as Day Seven) again tonight. That’s because there’s rain forecast next Thursday.

The actual value to rain in the Coachella Valley (Palm Springs area) is debatable. We average less than six inches per year. The majority of our water comes from an underground aquifer. It would be long gone if not supplemented by water piped in from Parker Dam on the Colorado River. Rainfall seeping down is a small piece of our specific puzzle.

Nature doesn’t provide nearly enough to support our population and the hundreds of thousands of tourists who arrive every week during the season.

Whether rainwater helps or not, people in the valley value it. Mentioning rain here is like mentioning snow in New England. It grabs your attention.

If you break down next Thursday’s rain forecast over Palm Springs, it comes to .06″. Tiny. Hardly noticeable.

A forecast for that small amount of liquid a week away is chancy at best, especially when you throw in:

EARLY NEXT WEEK A GULF OF ALASKA LOW WILL DEEPEN OVER THE PACIFIC NORTHWEST AND SEND A SERIES OF SHORTWAVES DOWN THE WEST COAST AND ACROSS SOUTHERN CALIFORNIA WEDNESDAY THROUGH FRIDAY. THIS UNUSUAL APRIL PATTERN WOULD BRING A DECENT CHANCE AT PRECIPITATION IF WERE TO UNFOLD. BUT THIS PATTERN HAS BEEN FORECAST SEVERAL TIMES THIS WINTER AND HAS EITHER 1) SUBSTANTIALLY WEAKENED OVER TIME OR 2) FAILED TO MATERIALIZE AT ALL. FOR NOW WILL HOLD ON TO A SLIGHT CHANCE FOR PRECIPITATION FOR THE MIDDLE AND LATER STAGES OF NEXT WEEK. – Area Forecast Discussion NWS San Diego

Wish us luck. It will get my attention on every newscast.

Who Said I’d Be Bored?

Some computer models show around an inch of rain in Palm Springs by Monday morning. That’s a lot in a place that floods easily. I spent time tonight explaining ‘washes’ to the tourists and snowbirds watching.

I’m forecasting the weather for the Coachella Valley at KMIR. The physics of weather are the same, but there are different tools to use.

Satellite imagery is a lot more important here. Anything coming from the Pacific is out of radar range nearly all the way to the coast.

I’ve been looking at a plume of moisture from north of Hawaii curving up the Pacific then back down the West Coast. It’s the big weekend weather maker for SoCal. The only way to see it is from the bird.

Saturday, while it’s raining in LA and San Diego, there will be partly cloudy skies over Palm Springs with a few sprinkles. We are protected by steep mountains, some over 11,000 feet tall.

On Sunday the moisture heads in from the south. No protection there! That’s when we get the bulk of our rain.

On top of the rain we’ve got wind for Saturday and as much as a foot and a half of snow in some mountain locations.

Who said I’d be bored forecasting here?

Rain For SoCal, Again

Once again we’re right on the 3-hour flash flood line. I expect some flooding. Homes in burn areas will be threatened by mudslides. A few inches of rain probable through this region.

Helaine saw the hashtag #stormageddon touted on TV a few minutes ago. SoCal is bracing… again. Is there some weird secret competition with the East on weather?

“Yeah… well… rain!”

Actually this storm looks very un-SoCalish. The radar from Vandenberg AFB shows a squall line out front. The HRRR agrees. The squalls remain intact as the line slides down the coast. Embedded thunderstorms are entirely possible.

We’ll have rain most of the day Friday though the bulk falls between 4-7 AM. We’re right on the 3-hour flash flood line, again. I expect some flooding. Homes in burn areas will be threatened by mudslides. A few inches of rain probable through this region.

The heaviest wind comes with the heaviest of the rain. Winds will gust out of the south. The wind map to the left highlights the higher ground where winds will be strongest.

If there’s snow for our two nearby tall peaks it will happen late in the storm. My second winter and no white so far.

Father north, San Francisco proper has gotten 2-4″ of rain with some windward mountainsides getting over 7″.

So far, this is the awful winter everyone was praying for!

Look Who Wanted Out Of The Rain

I’m not sure what kind of sensors worms have, but as I knelt down with “Clicky” the closest worm raised its head (or whatever the front end of a worm is called).

We’ve have two days of rain in SoCal. Very unusual. Yosemite Falls is falling, reasonably rare for December. Up north in San Francisco the rain has set records!

Through 7 a.m. Wednesday, San Francisco had received 1.36 inches of rainfall since midnight. Combined with 1.61 inches received yesterday we have a 2-day total of 2.97 inches. With more rain on the way, Wednesday will be the rainiest 2 days in San Francisco since at least January 2008. – Roberta Gonzalez KPIX

Here at the Casa de zorro (translate it–go ahead) we have new visitors driven up by the water seeping down. Worms!

This was a common occurrence in Connecticut, not so much here. And these worms are different. They’re very slender. Hollywood worms!

I’m not sure what kind of sensors worms have, but as I knelt down with “Clicky” the closest worm raised its head (or whatever the front end of a worm is called).

When the sun returns, the worms will disappear. Until then they’re a little creepy.

Let’s Look At Clouds From Both Sides Now

If it looks like the clouds are boiling, just like a pot of water on the stove, it’s because the dynamics are very similar. Heat is being transferred upward through convection.

We seldom get the big picture of what’s on the radar by just looking at the sky. Not today. Today is different in SoCal.

The atmosphere is unstable on the the other side of the Santa Ana Mountains, around 30 miles east of me. That’s where the radar (at the top of this entry) shows strong thunderstorms.

What’s striking in the time lapse below are the mid and upper levels of the clouds producing the storms. There are no clouds in the way blocking my view.

If it looks like the clouds are boiling, just like a pot of water on the stove, it’s because the dynamics are very similar. Heat is being transferred upward through convection.

The heavy rain and lightning bolts are out-of-sight behind the mountains. Here, I only see the signs. Everything is moving north and will soon be gone.

Gray And Gloomy

In SoCal people look forward to these gray days as a break from our endless sunshine. An OC native I spoke to yesterday was curious if I missed rain?

Right.

I wanted to say, “You’re nuts.” I held my tongue.

When I got up this morning (OK–it was afternoon. So shoot me.) the sky was gray. Not as bad as the photo (above) from the Mt. Wilson camera… but still gray. That’s not unexpected this time of year. May Gray is a well worn California phrase.

As it turns out, what looks like typical SoCal marine layer cloudiness is anything but! There are moderate to heavy radar returns from Central and Southern California.

The NWS office in San Diego describes it this way:

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE MOUNTAINS AND DESERTS THROUGH THIS EVENING…WITH ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE WEST OF THE MOUNTAINS.

There are reports of street flooding in San Diego. Storm drainage isn’t very good in most older neighborhoods. It doesn’t take a lot to flood.

Even though these cells are moving in my direction it’s likely few (if any) will get here. The mountains east of us enhance the rainfall on the desert side, then stabilize the airmass as it moves back to lower elevations.

In SoCal people look forward to these gray days as a break from our endless sunshine. An OC native I spoke to yesterday was curious if I missed rain?

Right.

I wanted to say, “You’re nuts.” I held my tongue.

Actually, I feel gypped on days like today. Stupid attitude, but it is what it is. My mind has independently decided it’s supposed to be sunny and mild every day. I have no control over the letdown I truly feel.

By tomorrow we should be back to normal.

And It’s Raining

“THE SNOW LEVEL IS CURRENTLY AROUND 6500 FT AND WILL DROP TO 4500-5500 FT BY SATURDAY MORNING. A LIGHT DUSTING IS EXPECTED AROUND 5000 FT ELEVATION.” That’s NWS/San Diego shouting in all caps. We can see Santiago Peak from the bedroom window, elevation 5,689 feet. I want to see it white.

Friday night in SoCal and it’s raining. Two lines of showers are moving down from the northwest. The first, lighter, line is nearly through. The next piece is just now moving out of LA.

We don’t get much rain here. Duh. The entire state is suffering through a drought. We are being asked to do less than I would have expected!

Since we came last June, as far as I can tell, all the rain we’ve had has been convective. Bigger drops. Instability. The dictionary definition of showers refers to a convective origin. There might be some lightning with this next round of showers.

I’m not a big fan of single site radar here. Back in Connecticut, I’d often isolate the Upton or Taunton radar to look for detail. Here, the three radars that overlay my house constantly show different returns for the same system! It’s crazy, but understandable considering the terrain. West Coast Geoff uses a lot more composite views. The radar at the top is from College of DuPage–a great weather site.

THE SNOW LEVEL IS CURRENTLY AROUND 6500 FT AND WILL DROP TO 4500-5500 FT BY SATURDAY MORNING. A LIGHT DUSTING IS EXPECTED AROUND 5000 FT ELEVATION.

That’s NWS in San Diego shouting in all caps. We can see Santiago Peak from the bedroom window, elevation 5,689 feet. I’m waiting to see it white.

Because of the topography there are lots of places where you can see 50 or more miles away with the naked eye. It is strange to drive around with the top down, looking up at snow covered peaks.

Bad weather doesn’t last. Tomorrow’s supposed to be back up near 70&#176.

Weather still fascinates me.

It Doesn’t Take Much To Cause Trouble In SoCal

The 4:00 PM PST rainfall totals are in for our second storm. If this was the East Coast or Midwest these numbers would be no big deal. Here in SoCal the bar for weather related tsuris is much lower.

We’ve had mud and rockslides, trees falling on homes and cars, rescues from the concrete channel known as the LA River and mandatory evacuations in Azusa and Glendora.

We’re not done! There’s another 1-2″ or rain due through early Sunday.

The threshold is lower now. The ground is saturated.

Helaine was shaking her head earlier as we watched a homeowner from Azusa interviewed on TV. He was talking about his fears. Mud was already flowing into his yard. He expected part of a hillside to let loose, wiping out a stand of avocado trees and probably taking down his substantial backyard fence. Left unsaid, whether his house might be destroyed too.

Why do people live in these susceptible areas? Simply put, it’s gorgeous.

If all you looked at was the hazards, no one would live in SoCal. We’re prone to fires, floods, slides, quakes and more. Of course everyone looks at those hazards, remembers the rest of the SoCal climate, then compartmentalizes them out of the equation.

After every disaster the most repeated word is, “rebuild.”

.ORANGE COUNTY COASTAL AREAS
 
 ID:     STATION            PRECIP(IN)    ELEV(FT)
 
 SDYBL:  YORBA LINDA            1.69         370         
 SDFRH:  LAKE FOREST            1.44         970         
 SJNC1:  SAN JUAN CAPISTRANO    1.34          75         
 SDLGH:  LAGUNA HILLS           1.27         400         
 SDSAA:  SANTA ANA              1.14         130         
 FUL  :  FULLERTON              1.13          96         
 SNA  :  JOHN WAYNE AIRPORT     1.12          50         
 CTMC1:  COSTA MESA             1.10          47         
 SDDPC:  DANA POINT             1.01         305         
 LGUC1:  LAGUNA BEACH           0.90          47         
 SDHTB:  HUNTINGTON BEACH       0.89           5     

  
.LOS ANGELES COUNTY METROPOLITAN  
AVALON INLAND..................... 1.29  
HAWTHORNE (KHHR).................. 1.40  
LA AIRPORT(KLAX).................. 1.62  
LA DOWNTOWN (CQT)................. 2.28  
LONG BEACH (KLGB)................. 1.03  
SANTA MONICA (KSMO)............... 1.68  
REDONDO BEACH..................... 1.28  
TORRANCE.......................... 1.11  
MONTE NIDO........................ 2.48  
BEL AIR........................... 2.60  
CULVER CITY....................... 1.30  
GETTY CENTER...................... 2.58  
BEVERLY HILLS..................... 2.39  
HOLLYWOOD RESERVOIR............... 2.01  
SOUTH GATE........................ 1.28  
  
.LOS ANGELES COUNTY VALLEYS  
VAN NUYS (KVNY)................... 2.60  
NORTHRIDGE........................ 2.08  
WOODLAND HILLS.................... 2.63  
AGOURA HILLS...................... 3.11  
CHATSWORTH RESERVOIR.............. 2.27  
CANOGA PARK....................... 2.21  
PACOIMA DAM....................... 2.80  
HANSEN DAM........................ 2.42  
NEWHALL........................... 2.99  
SAUGUS............................ 1.47  
DEL VALLE......................... 1.45  
EAGLE ROCK RESERVOIR.............. 2.60  
PASADENA.......................... 2.64  
ALHAMBRA.......................... 2.06  
EATON DAM......................... 2.36  
LA VERNE.......................... 1.61  
SANTA FE DAM...................... 2.19  
POMONA............................ 1.12  
CLAREMONT......................... 1.28  
  
.LOS ANGELES COUNTY MOUNTAINS AND FOOTHILLS  
SANDBERG (KSDB)................... 2.18  
INSPIRATION POINT................. 3.35  
WEST FORK HELIPORT................ 5.67  
SANTA ANITA DAM................... 2.79  
SAN GABRIEL DAM................... 4.72  
MORRIS DAM........................ 3.19  
CRYSTAL LAKE...................... 5.78  
OPIDS CAMP........................ 6.33  
SIERRA MADRE...................... 2.39  
TANBARK........................... 3.16  
SAN ANTONIO DAM................... 1.67  
MILL CREEK SUMMIT................. 1.28  
CHILAO............................ 1.27  
MT BALDY.......................... 4.52  
WHITAKER PEAK..................... 3.58  
WARM SPRINGS...................... 2.38  
ACTON............................. 1.66  
CAMP 9............................ 2.06  
  
.LOS ANGELES COUNTY DESERTS  
POPPY PARK........................ 2.64  
LANCASTER (KWJF).................. 1.54  
PALMDALE (KPMD)................... 1.02  
LAKE PALMDALE..................... 0.63  
SADDLEBACK BUTTE.................. 0.36  
VALYERMO.......................... 2.54

I’m This Storm’s Spectator

You will have to excuse me tonight but I’ve become obsessed with our upcoming weather. This is a first for me. My first real California ‘winter storm.’ I’m trying to gauge how pre-game coverage matches what really happens.

Viewers often accuse TV stations of hyping weather for ratings. I didn’t think we did, but this is an opportunity to watch as an outsider.

The late run of the GFS is VERY wet through the weekend. More rain than we’ve had in the last year!

For 28 years I lived in Connecticut. The hills there were more gentle than California’s steep slopes. These amplify rain’s effects. Most people are surprised to see the width of some of our washes (dry river beds). The mountains will fill those washes very quickly.

But, again, I haven’t experienced this first hand. Most of my SoCal weather knowledge is book learning and observing from afar.

Where there have been large fires, where brush hasn’t yet reestablished itself, expect landslides. Truly, insult added to injury. Haven’t these people had enough?

The vast majority of hills will remain intact. It’s just tough to say which ground is solid at any given moment.

I can’t imagine the big stuff will be widespread. We had around 800,000 without power in Connecticut after Hurricane Sandy. That seems very unlikely. Widespread outages of any number seem unlikely.

The main thrust of the first wave of rain is still offshore to the northwest of us. The GFS says .42″ at John Wayne in Santa Ana, with most centered around morning rush Thursday.

Round two gets here early Friday. For this the GFS says 3.349″ at Long Beach over 48 hours or so&#185. That’s a huge amount of rain for this place to absorb. It won’t be absorbed gracefully or easily.

The good news is there are few basements to flood!

&#185 – QPF, how much we’ll get, is the least accurate surface forecasters make. Giving it to the thousandth of an inch, as I did, is ridiculous.

Graphic courtesy coolwx.com

Rain Coming And Folks Are Excited

“It will be good for the state.” Those were Helaine’s words a few minutes ago. We were talking about the threat of rain in SoCal. We’ve had hardly any since last year’s rainy season–also a dud.

The image above is a screengrab from the afternoon GFS, using BUFKIT. If you want to know what kind of person I am, I find it fascinating. I like charts, graphs and numbers. They like me back!

I’m not going to be a whiner. Drought sounds and is bad. However, our infrastructure was designed knowing we get droughts. It needs much less than normal rain to work properly. No one is being forced to conserve.

We will finally end the fire season. That will be a relief to many. California has a tendency to burn.

Our first rain comes Wednesday evening. A cold front off a low hitting the California Coast near the Oregon border is the trigger. Not a lot. The GFS says around a quarter inch.

Meteorologists are lucky here. I’ve read and seen all sorts of quantitative precipitation forecasts (QPF). It’s our least accurate prediction. They’ll all be wrong, but unlike snow, no one will check up on them.

The rain (and snow) should be significantly heavier farther north, including the Sierra Mountains. They are our sponge! Snowfall in the mountains is slowly released through early summer. Much of what would run to the ocean now flows toward the Southland.

Water from the Sierras is California’s lifeline. It’s how we house people and grow crops in the desert! Like so many other spots in America, we have overcome nature to tame a place not naturally suited for any of what now happens on it.

The second wave of rain arrives Friday morning. The GFS shows three inch range, much more than this area can easily perc. Flooded intersections and slow traffic will follow. Thunderstorms, less frequent here than back east, are possible with heavy embedded downpours.

NEXRAD is pretty bad here. Too much topography. There are lots of holes using individual radars. This is one place where composites help.

During these storms our temperature will stay in the 60s.

Friday’s deluge will taper to showers then some scattered drizzle under cloudy skies through Sunday. People here are looking forward to this brief change. I will miss my friend, the blue sky.

Like Paul Blart, Mall Cop

At 11:15 PM PST/2:15 AM EST

Observe and report. Like Paul Blart, Mall Cop, I’m observing and reporting.

First stop, radar. It’s active. Snow, identifiable by radar only recently, is the only precipitation being seen at the moment. It’s moving west-to-east.

Meteorologists call the radar’s targets, hydrometeors. Cool name.

We can detect rain, snow, hail, sleet, whatever. If a radar beam can bounce off it, it’s tracked.

Most times the radar is amazing. Not always. I’ve seen storms develop in an unusually bright patch of ground clutter. Surprise! Where did that come from? A once every few year event.

All my observing tonight is on the College of DuPage weather website. They carry nearly every product with well chosen color tables. Highly recommended.

The surface map shows the low pulling east, leaving New England. There’s more moisture following and colder temperatures. The snow isn’t quite finished.

Before ending this morning that additional snow will cover the slushy wet mess already on-the-ground. Up to a half foot more will fall in scattered sections of the Litchfield Hills all the way to the UCONN campus. Most areas a few inches less. Even less on the shoreline and near 395.

But still, look what it’s covering!

Oh–and windy and much colder.

The amount of forecast and observational data available is immense. New tools arrive all the time. For nerds like me, this is heaven. Forecasting in pajamas!

Albert Hammond Lied–It Rains In Southern California

I was in bed and asleep at the unusually early (for me) hour of 2:00 AM. That’s when the downpours came to Irvine. It was as if someone had thrown the rain switch. Nothing to everything in a flash!

All the windows were open. Thankfully there was little wind. It didn’t rain in.

Summertime rain in SoCal is the exception. In fact, for our first month in Orange County this is my only run-in&#185. Nearby John Wayne Airport reported 1/8″.

Last night while out walking Helaine noted, “The sky looks bigger here.”

Fewer low and mid level clouds mean fewer obstructions. Clouds are often seen when they’re farther away. The sky does look bigger.

We’re going to a restaurant at the beach this evening for my birthday. It should be sunny by this afternoon. I’m looking forward to sunset over the Pacific.

Like I said, summertime rain here is the exception.

&#185 – Helaine was out shopping a few weeks ago when she saw a handful of drops on an otherwise lovely day.

Everything But Snow

Wednesday will be a stormy day in Connecticut. This is a big systems and it will be tossing its weight around!

As I type this (Tuesday at 4:00 PM) there are three Tornado Watch areas, a Severe Thunderstorm Watch, scattered Winter Storm Warnings and all sorts of flood and wind warnings from this singular system. Most of what’s up in Connecticut today (Tuesday) has been issued in anticipation of tomorrow.

Not so fast Litchfield County.

Light rain starts later tonight statewide. In the Litchfield Hills there’s a chance some of that rain will fall as a liquid, but freeze on contact. There’s a Freezing Rain Advisory for Litchfield, but only until 10:00 PM. That’s because this storm is packed with advection!

ad·vec·tion (d-vkshn) n. The transfer of a property of the atmosphere, such as heat, cold, or humidity, by the horizontal movement of an air mass.

There will be enough warmer air headed our way that temperatures will rise through the night. That’s why the advisory expires at 10:00 PM.

By midday Wednesday the intensity of the rain picks up. Thunderstorms seem probable.

From my trips outside with Doppler I can assure you the ground is frozen or close to it. Little of this rain will ‘perc.’ Flooding from runoff is likely, especially near small brooks and streams and on low lying roads.

By Wednesday evening the wind begins to pick up. Winds of 15-30 mph with higher gusts are likely. Scattered limbs and power lines will fall.

Windblown rain: No fun!

The rain ends Thursday morning, but not before we get a lot–probably an inch or two. Meanwhile, the wind will continue to howl and the mercury will plunge.

On one of my forecasting charts the graph for temperature resembles the climb to the first hill on a roller coaster. Steady up, then a plunge down! We’ll hit Thursday’s high temperature at midnight then tumble for most of the next 48 hours. Low 50s Wednesday, but 20s and low 30s for the high Friday!

The funny thing is, this late January storm will bring everything but snow.

Maybe not funny. Quirky?

There are chances for light snow Saturday and Monday nights. Let’s get through tomorrow first.

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