Much of the fall has been very dry across large portions of California, and what precipitation did fall came relatively early in the season and was generally not sufficient to generate meaningful runoff. The past week has seen one of the most powerful Santa Ana/offshore flow wind events in recent memory, with reports of widespread damage and wind gusts well in excess of 100 mph on some mountain peaks. Unfortunately, the prevailing pattern is not showing many signs of change in the near future.
GFS 00Z Analysis 500 mb heights, 12Z 12/3
A large, powerful and persistent blocking ridge has set up in the Eastern Pacific, creating high amplitude meridional flow upstream and downstream of the block (poleward in the Central Pacific, equatorward over the Great Basin and Intermountain West). Occasional disturbances riding down the backside of the block have generated strong pressure gradients and powerful offshore winds over California and other Southwestern states in recent days, and will most likely continue to do so for the next 1-2 weeks as the blocking ridge holds strong.
Prospects for a pattern change in the immediate future are pretty slim. These sorts of blocks can be difficult to break down, usually requiring an easterly extension of the East Asian jet to displace the Central Pacific ridge. Two other options are for the block to retrogress and the equatorward flow on the east side to shift westward, or for the block to slowly weaken with time. The former option brings the possibility of Arctic intrusions along the West Coast, and the latter brings the possibility of very slow-moving cutoff systems forming southwest of California. One caveat is that the MJO does appear to be fairly active in the Western Pacific, and the GFS is indicating that the signal may begin to propagate eastward over the next 1-2 weeks. If this does indeed occur, there is some hope for the block to break down and for more zonal flow to take over along the West Coast. We’ll just have to see about that…
Despite early fall rains in Northern California, very dry offshore flow with continuing strong winds in the higher elevations is beginning to lead to fire weather concerns. Though December Red Flag Warnings are not particularly rare in Southern California, they certainly are in the northern half of the state. The possibly very strong wind event for later next week could result in critical fire weather conditions from the Sierras to the Bay Area, which would be extremely unusual, to say the least.
We have now entered the critical period for Northern California rainfall. Each day that passes without precipitation adds to the deficit that must be made up later in the season if we are to avoid a significantly below average water year. Since the first half of December appears unlikely to produce that sort of pattern, we may have to hope for wetter conditions in the new year.
© 2011 WEATHER WEST
The Pacific ridge is stuck around 130W at this time, and as long as it stays there, Socal (and maybe most of CA at that), will remain in an almost perpetual offshore flow with bursts of Santa Ana winds at times of varying strengths. I have seen this pattern in other years between Thanksgiving and New Years’, so it is fairly typical in Socal (I believe this time period is overall the windiest for my area here in Orange on average). However, I can’t remember what happened in Norcal during those other years which had series of Santa Anas down here.
Rainfall totals so far this season in the Bay Area are similar to those in coastal Los Angeles and Orange County, averaging mostly between 1.5 and 3 inches. Coastal and inland (not desert) portions of San Diego County south of Oceanside have been wetter with between 3.7 and 4 inches.
I feel that Socal has gotten off to a good start rainfall-wise, but Norcal needs more storms very soon, and I don’t want to see this dry spell go on for weeks on end. Hopefully the entire state receives rain and snow later this month when this block finally shifts or breaks down.
Today – 12/3/11 We had a wind gust of 31 mph —- Hi of 58 Low of 37.2 — cureently at 935pm its 39.5 —–
Update the overnight low went down to 35 for 12/3/11 –just reached close to midnight
Down to 30 in Redlands, Ca for 12/4/11 —–
32 last night 35 this morning. I am sure my orange tree isn’t going to be to happy.
It’s a much colder start to the season than in the last few years. 5 day below freezing cold snap, haven’t seen this except in jan/feb. Should get into the upper 30′s today though, maybe. Snow is still powder from last thursday!
Starting Monday the GFS keeps us active, or very close to, for a good week, and of course cold ones….NWS has introduced precip for socal on Monday
So the GFS has changed again and now has a storm into socal. Things brings two things to mind – one that the GFS never tracks pattern changes coming from very far out. Once I saw a storm appear 13 days out that actually happened but it usually can’t pick up a pattern change until a few days before. The other thing I wanted to comment on… someone mentioned that rain usually follows strong Santa Ana winds. This is definitely true, years ago my grandpa said they used to have a rule, rain three days after a strong Santa Ana. I’ve been watching this and while it isn’t always exactly three days, the rule often holds true even when no rain is in the forecast. It’s the blessing/curse of a Santa Ana – the rain is a blessing unless it falls right after a huge fire, and causes mudslides, in which case it can be a curse. (though sometimes it puts out a fire, even better).
I’ve been watching the models closely, mostly the GFS and NAM, and they have been all over the place. Also, NWS doesn’t seem to be following them very closely. Models have been occasionally showing the chance of significant snow in Vermont on Thurs/Fri but the NWS isn’t even mentioning it in their forecast, and mostly discounting in their discussion. I guess this is where experience comes in but I’ll still be watching to see if we get the snow. Earlier this year a somewhat similarly discounted storm turned into that huge blizzard in southern New England.
I wonder if tonight for my area it will get lower than 30 something that hasn’t been done since late February of this year.
Was 25.5 on my orchard therm.. in Redlands, Ca 12/5/11
hey you stole my cold air, lol, same low temp up at my place in running springs.
Today we hit 42F!
Looks like more trouble with next weeks low, possibly ditching us for some baja fish tacos & cerveza…
I have been on the road heading home from Nashville. And it is cold, had to delay my return a day because of the snow on I-40. we hit snow on the the ground from Oklahoma to Flagstaff, was 4 in Amarillo yesterday morning and it is 5 here in Flagstaff. Highs been mainly in the 30′s on our traveling. Does look cold at home for us, models look like the cold continuing out 14 days plus. Look like Dan’s inside sliders continue. Inyo looks like you picked up some snow yesterday.. Looking forward to getting home this afternoon.
Yep, we got some snow! Only a couple of inches but it’s beautiful, and it’s finally seasonably cold so it didn’t just immediately melt off. Looking like it will be fairly cold from here on out but not anything unusual and not as cold as Amarillo, even.
Looks like the GFS has another cutoff low for Socal, but it changes every run so we’ll see.
The cut off low is looking stronger for the 1st part of the week with another low following the 1st. T-storms and low snow levels are possible. Good to be home. I am glad you got some snow Inyo. Enjoy.
Looks like we could get shafted again is the low keeps tracking more into San Diego. This winter is going to suck at this rate.
Seriously. I am sick of these “outside” trackers. They have been happening way to often and are starting to get on my nerve.
I am getting tired of this ‘outside slider’ track as well and I am also not used to seeing it happen as often as it has this fall. I would just like to see more of these storms make a direct hit on CA, instead of Baja, so the mountains can receive more snowfall as the Sierras have been missing out.
The good news is this storm, at least according to the latest NWS San Diego Forecast Discussion, will be tracking from north of Point Conception to the S and SE, paralleling close enough to the coast for a fairly good soaking of rain as opposed to too far offshore.
I want some snow for Redlands, ca — that would be a nice xmas present ???
It just started raining here in Orange within the last 20 minutes or so, and it has been enough to wet everything and even just a bit of puddling in the patio.
Drove through that last night on the way home from San Pedro. Same here this morning. Lot of rain off shore this morning, but the overhead seems a bit too high to bring any to rain. Sky has that same look about it when a storm rides up over a bubble of high pressure. Stand by to stand by.
A band of moderate/heavy rain has stalled over LA/Orange county line. Its been coming down hard here in Whittier, already 0.30
Well, it did rain. We got about 20 minutes worth of a steady medium density shower. So it did meet the 100 % chance, and I have visual
on more coming from the southwest.
Its raining in Redlands, Ca 12/12/11 — got our first 0.01 at bout 10:15am — hopefully we will get more — low so far only 44.1
Some funnel clouds have been reported near San Diego.
It has been raining here lightly to moderately in Orange since sometime very early this morning. I haven’t checked my gauge, but I would guess by the duration and intensity of the rain along with the ponding of water in low spots of my yard that .5″ or so has fallen so far.
5″ snow up here – Running Springs since 10am, no wind, 30F. Snow falling just below 4000′ & slush/sleet to 3000′
After a lull in the rain this afternoon, Orange is getting some heavier showers now. According to the radar, there was (or still is) a special marine warning just off the coast of Huntington Beach or whereabouts as of a few minutes ago.
Well, unfortunately, a lot of San Diegans have spent the day at the semi annual “Hey Dummy! When it rains the roads get real slippery! Slow down!” school for stupid drivers. A-gain!
Latest count 140+ collisions, solo spin outs, ditchings and general dumb stuff. A normal day is 30 to 40. Very unfortunately, 2 of them are no longer with us.
Lets be careful out there!
LOL at TOM your commet was funny
Tom you are right, folks in San Diego, don’t get it. slow down when it rains, lots of accidents. Picked up .80 so far today at the house (Granite Hills) a lot of heavy showers, in fact had a thunderstorm this afternoon. Looks like it will pick up again tonight, radar is showing a pretty good line of showers coming in. Also welcome Tom.
Thanks, Ken.
Good to be back for a few.
Was 49.1 for a high and a low of 43.3 in Redlands, Ca Today 12/12/11 — Rainfall of 0.27 — looks like Redlands, Ca didnt get big amounts like other stations/cities — Tom — I think the Redlands, Ca area has the same problem — bunch of stupid people who dont realize you have to slow down — I myself saw people spinning out — going too fast in the rain —
Yeah its the curse of having dry roads 90% of the time. There’s always that 5 -10% that never seem to get the memo.
Talk about turning off the spigget – 6″ snow is what we tapped out at, maybe some showers today but not expecting it, been high and dry since about 5pm yesterday…so much for NWS 12″ to 18″
I think most of the activity last night was offshore and just along the immediate coast as the storm as like so many others this season tracked offshore. It didn’t rain too much here in Orange last night either, but we did get a good soaking from yesterday morning into the late afternoon.
Started off strong but the end of the day didn’t do so well. We got 0.65 with the storm.
.65″ also fell here in Orange from this latest storm. This amount fell within the NWS forecast total ranges, which was between 1/4″ and 3/4″ in the coastal areas of Socal. Looks like Flagstaff, AZ got a good amount of snow from this one as well.
We had a steady soaker here until about 130 or 200 it finally let up, then a couple showers late this afternoon Navy Field at IB reports about an inch.that puts us about 3.5 or 4 inches so far this year. The bermuda grass in the back yard looks like it took a frost hit, all yellow, but the St Augustin stuff in the front is lovin all this rain, its green as ever, strange.
Does anyone have a link to access weather data for mexico (baja california specifically)? It would be interesting to see YTD precip totals / averages etc etc., see how they’re doing with all these storms tracking further south.
Alan — My station in Redlands, Ca only has 2.37 — Tom in San Diego — farther south says hes at 3.5 to 4.00 —
Cold and wet yesterday here at the house(Granite Hills) High 49 low 44 picked up .27. Storm total was 1.09, for the YTD 4.99. unusual for this many closed lows to form here in the southland, I don’t seem to remember a pattern like this one. Looks like another one for tomorrow afternoon into Friday with strong winds following for the weekend.
Ken — is that high and low for dec-13 or dec-12 ????
Hi redlands, it was for the 13th. the High for the 12th was 52
Todays 12/ NAM/GFS shows the low going a little more West with a bit of moisture and a decent amount of wrap around moisture. Might get a little interesting.
Things are getting real interesting looks a bit like April 1st event or the event we had in May of 08
Just had a Tstorm in Rancho Cucamonga, heavy rain, winds & thunder. You can see building up on radar.
Thunderstorms approaching Whittier.
Radar is looking interesting, SD NWS office issued a special weather statement for Funnel clouds with this system and Thunderstorms, I see you are getting them north of us. Big Bear is reporting snow. Might be a fun night.
Wow, what a storm…it was like a storm that came from the midwest!
I was out and around today and then saw really dark clouds approaching from the north and northeast and then on my way home it started raining. It looked like a band of thunderstorms by the way the clouds looked, but I didn’t see any lightning, though. It is still raining here in Orange, light to moderate, as I type.
At my station in Redlands, Ca — we didnt get any measureable rain — was cool only hit a hi of 59 and a low of 35 —- too bad we didnt get any rain or hail
.13″ fell here in Orange from this little storm. I didn’t really believe that it would rain today despite there being a 20% chance in the forecast as I thought the storm would track further inland, but I will gladly take any rain that falls here. I never did see any lightning as others on this blog saw, but it sure looked ominous and unstable late this afternoon before those cells moved through.
It was weird, in no more than 1/2 square mile near victoria gardens it had hailed a good couple inches, the ground and the roofs were all white, looked like snow! and of course the 15 was a mess.
The Santa Anas have been blowing strongly here in Orange all morning and continue to be quite strong right now. I haven’t gone out to measure the wind speed to determine the exact strength of the gusts.
Ken mentioned not remembering a pattern like this year’s.
I do,but it was in 1984. Longer than I care to think about. We had our first rain on Thanksgiving Day that year. I remember it only because I had the duty, and got to digest my turkey that evening standing a cold rainy a quarterdeck watch at NAVSTA 32nd St. That was one of a series of rainy winters in the early and mid 80′s, before we entered the present droughty era.
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Here’s a summary so far on the rain totals for the West Coast (as percent of average) since July 1, going from north to south:
Seattle: 67%
Portland: 73%
Eureka: 70%
Sacramento: 48%
San Francisco: 49%
Paso Robles: 99%
Los Angeles: 126%
San Diego: 183%
Doesn’t look too much like a La Nina yet, huh!? Of course, it’s still pretty early in the rain year and the La Nina’s not that strong this year.
sc100 all yes we are feeling La Nina right now with the blocking high wish is keeping N CA vary dry we are well be low average for are rain fall here in N CA even WA and OR is feeling this even no they sould be a tad wetter then this but yes N CA is feeling is La Nina right now and so far DEC have been vary dry with litttle too no rain fall i hop but this dos not keep going so the rain fall % you see for Sacramento and SFO is well be low average for this time of year we sould be at all most 80 too 90% of average right now for sac i hop things turn a round in JAN or things may not look too good come summer
all so i for got too add too my last commet is that this is a 2nd year La Nina wish it turning out too be march dryer then last year La Nina other thing i like too point out too you sc100 is that La Nina years dos not all way means they will be wet ones in fac La Nina are dryer years for N CA and the stronger the La Nina comes the dryer N CA gets weak mod or strong La Nina years dos not all ways mean we will see wet winter now like this winter has you can see are mod La Nina is turning out dryer so some are we too vary wet and some are dry too vary dry now 2010 was a strong La Nina year and a wet too vary wet one this year mod La Nina is turning out too be dryer for N CA
Today is a classic day where the forecast is about as confusing as it gets. Might be another interesting day.
Davis is right. La Ninas are usually dry, for all of California. San Diego and LA are lucky so far in that we have gotten in the benefit of being on the north end of two high and outside sliders, to use the baseball reference. Same as last year, we could see a change up pitch next month, a dry Jan, which wouldn’t surprise.
These “sliders” really have been weird. I’m glad you guys down south are getting some rain right now so that in case the rest of the season does turn dry, you’ve at least got something early on to help you with the yearly totals.
I checked on some La Nina stats and Sacramento’s average precipitation during La Ninas comes out to 96%, excluding last year, which was a wet one. Two of the last five big floods up here (1950 and 1955) happened during La Nina years and the driest year we ever had (1975-1976) was during a La Nina year as well. Most of the La Nina years tend to be average to slightly below average, usually nothing crazy in either direction. Of course, this mixes in La Ninas of different strengths. I’m not sure of the breakdown by intensity. The closest thing to a “sure bet” up here are strong El Ninos. Whenever we’ve had them, we’ve had big rain years. Anything besides that and I’m thinking the rain year could go in any direction.
Redlands, Ca is getting the shaft from this inside- slider storms — its half of December completed – with only 0.27 of rain — last year we had over 10 inches of rain —-