California drought continues; few prospects for short-term relief

Filed in Uncategorized by on October 22, 2013 81 Comments

Dry and drier still: a story of persistent atmospheric ridging

It has been a very dry couple of years across the state of California. With the major exception of the December 2012 deluge in the northern part of the state–which (along with aggressive water management strategies) is largely responsible for the modest water reserves that do remain in the state’s major reservoirs–exceptionally dry conditions have been the rule nearly statewide, even during the traditional winter rainy season. Unfortunately, at least in the short term, there is little evidence of drought-busting rains on the horizon.

image

From NOAA/NWS

 

Though much of Southern California has already received some healthy early-season convective precipitation associated of a cut-off low that moved over the California Bight earlier this month, the rest of the state is experiencing an almost entirely dry October–a situation which, while certainly not unprecedented, is not helping to alleviate drought concerns. Current numerical model simulations depict the continued dominance of a strong ridge over East Pacific heading into early November, so prospects for meaningful precipitation are quite low for the next 1-2 weeks.

GFS 00Z analysis depicting quasi-stationary high-amplitude ridge over the Eastern Pacific and West Coast.

GFS 00Z analysis depicting quasi-stationary high-amplitude ridge over the Eastern Pacific and West Coast.

One possible short-term caveat is the current high level of tropical cyclone activity in the Western Pacific. There are currently two active typhoons near Japan–including Category 5 Supertyphoon Lekima–both of which are expected to recurve into the Westerlies before making landfall. This means that a considerable amount of energy will be ingested into already-amplified flow pattern over the Pacific over the next few days. Situations such as these historically give the models trouble in the 5-10 day range, so it’s possible that some of the remnant energy from these typhoons could help dislodge the blocking pattern sooner than expected. In the meantime, check out this impressive infrared satellite imagery centered on the West Pacific:

NRL/NOAA

NRL/NOAA

 

Long term prospects: ENSO-neutral winter, but potential early signs of change?

The El Nino/Southern Oscillation is one of the most reliable intra-annual indicators for California precipitation, especially when there is either a pronounced La Nina or El Nino event in progress. This year, there is neither–indeed, for the better part of three years, conditions in the tropical Eastern Pacific Ocean have wavered between very weak La Nina conditions and effectively neutral conditions. Current sea surface temperature anomalies (and subsurface anomalies, for that matter) are not impressive, and there is near consensus among the operational numerical models that conditions for Winter 2013-2014 will be ENSO neutral. For this reason, it is difficult to make a meaningful long-range projection for California cool-season precipitation this year on the basis of ENSO.

 

CPC/IRI

CPC/IRI

Worth noting, however, is that a majority of numerical models are starting to indicate the emergence of a positive ENSO signal beginning in spring 2014. That is, more models are projecting El Nino conditions for late spring and early summer 2014 than are projecting either neutral or La Nina conditions. The models used to predict ENSO at lead times of greater than six months are subject to considerable uncertainty, but this recent trend appears to be sustained over the last couple of months and may be supported by some observed pooling of subsurface warm water in the western tropical Pacific. While this certainly won’t have any bearing on winter precipitation in 2013-2014, it is something interesting to keep an eye on for next winter.

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  • Tom in San Diego

    Just beginning another trip to Westpac. Will be keeping an eye on the recent bloom of cyclonic activity, both as to the effects we expect to encounter along the southern or winter westward track as that moisture becomes entrained in the prevailing westerlies, as well as activity in the Philippine, East and South China seas once we get closer to Japan and Taiwan. Winter is always an interesting time over there. There is no typhoon season, they can and do occur through out the year.

    • Dan the Weatherman

      I am wondering if this recent burst in typhoon development in the Westpac is contributing to this large scale blocking pattern that has been keeping the entire continental U.S. west coast dry during the last 10 days.

      • Perhaps, although the present storms have yet to transition into extratopical systems/be entrained in the Westerlies. There has been quite a bit of activity for the past 2-3 weeks.

  • Nicholas

    While that 18z is highly unlikely it is a bit funny. Looks like something in summer for the long range.

  • kcanton40

    Hi Nicholas,

    What do you mean, “looks like something in summer for the long range.” Explain or elaborate please!

    • Shady Blues

      At the end of the 18z GFS run, it shows a tropical storm/remnants impacting Southern California. This was a common model theme in summer, especially toward the end of the run. He finds it ironic that we are getting such solutions in Fall.

      • Dan the Weatherman

        I have noticed that same thing on a couple of 0Z GFS model runs in the fantasyland range either late last week or earlier this week in which a tropical system comes up Baja and its remnants impact Socal and Arizona. Of course that would be highly unlikely this late in the season, but certainly would have been a possibility if it were late August or September.

  • redlands

    Well I hope we have a good rain season —- I was looking at my rain records — back to 1981-82 — I’ve only had 4 seasons where I consider a good season. My definition of a good season is 20.00 inches or more. Seems like in my area that we have to have 1 inch or more per month before Jan-1 and or one or two good monthly rain totals before Jan-1 — Along with this we have to have one to three good monthly rain totals Jan-1 and on to have a good rain season using my definition of 20 or more inches. October 2004 Redlands received 6.07 of rain – ending the season with 24.21 — — The last good season we had — but falls below my definition of 20 or more inches – was 2010-2011 — when we got 10.46 of rain in the month of Dec 2010 — ending the 2010-11 with 19.29 — So time is ticking down — we need to start getting in the wet cycle. Redlands for 2011-12 with 7.15 and 2012-13 with 8.67 has had 2 lousy rain sesaons.

    • Dan the Weatherman

      2012-13 was a really lousy rain season, along similar lines to 2001-02 and 2006-07. The main culprit in my opinion, and I have mentioned it several times already before, is the -PDO (cold phase of the Pacific Decadal Oscillation), +AMO (warm phase of the Atlantic Multidecadal Oscillation), and weak to neutral ENSO (El Nino Southern Oscillation) combo. It doesn’t matter if it is a weak La Nina, a weak El Nino, or completely neutral in this case, as they all tend to lead to similar results in each case. Unfortunately, as far as I know, the state of all three factors is the same this season as last year, and that leads me to believe that another drier than normal season is on the way. However, I don’t think it will be as dry because downtown Los Angeles has never had to sub 7″ inch years in a row.

      The one thing I would like to point out, though, is the the Atlantic was far less active in terms of tropical activity, especially as far as hurricanes go this season. I am wondering if this is possibly a sign that the Atlantic may soon be returning to its cooler phase (-AMO) in the near future. I heard Bryan Norcross make a comment on TWC awhile back as he was analyzing the lack of major activity of this year’s hurricane season, wondering if maybe the Atlantic is heading toward the -AMO phase, but I haven’t heard any follow-up information, so I don’t have very much to go on right now. A change to -AMO would, in my opinion, help out with rainfall prospects in CA even if the other factors stayed the same, as the mid-late 1960s (including ENSO neutral years) turned much wetter here when the AMO flipped to negative in 1963.

      • The cool phase of the PDO has definitely not helped our winter precip prospects these past years. I’m less convinced that the AMO has the same kind of direct effect–as a defined mode of variability, it’s less clear exactly what the physical mechanisms are behind its teleconnections in western North America. In any case, short of a major change in the state of the PDO, I think the only thing likely to bolster precip in the shorter term (next few years) is an emerging El Nino, which isn’t in the cards for the 2013-2014 winter.

        • Sidebar: the impressively inactive Atlantic hurricane season this year is largely due to excessive amounts of Saharan dust, which strongly inhibits vertical instability in the tropical Atlantic. While SSTs were certainly not as high as they have been in some years during the past decade, the dust appears to be the major “hurricane killer” this year.

          • Dan the Weatherman

            I had been hearing that there has been high amounts of Saharan dust and how that was suppressing activity for a good portion of the season. I will be keeping an eye on the Atlantic SSTS in the near future to see if they continue a downward trend or not.

      • redlands

        Yes — I agree the 2001-2002 was a horrible season — I only recorded 2.78 of rain for the entire season — the wettest month was November 2001 with with0.87

  • Shady Blues

    There is a very pronounced difference in model solutions right now especially over the next five day period. Both the Euro and the GFS models depict a strong low dipping from the north.. However, the Euro has the low tracking much further west and has it over our area. This solution would bring us much more dynamic and wetter weather than the GFS solution. In fact, the Euro solution looks eerily similar to the storm we had earlier this month! Can you Deja Vu? What model will overcome? We will see!

    • Dan the Weatherman

      It seems like many of our storms the last 2 years or so have been coming out of western Canada, taking a more over land trajectory as opposed to coming in from the Pacific with more moisture. The result has been storms with limited moisture and consequently reduced rainfall amounts for our area. The blocking high in the NE Pacific and/or Gulf of Alaska has been rather dominant lately.

  • Nicholas

    I would love for the Euro to be right about the storm system. The GFS has been on the money the past few falls making good calls as to if the storms track to the east or to the west. I think it will be right again.

  • Shady Blues

    Unfortunately, it looks like you are right. Recent ECWMF runs are in line with the GFS.

  • Nicholas

    Unless a strong thunderstorms rolls of the mountains Whittier never does good at all in this flow pattern. I think that with the way the hills are set up it kills the moisture. I have noticed over the years with storms like this we get shafted and mostly get a quick convective shower in the morning then a shower at sunset.

  • Some scattered showers will continue today across parts of the state, but on average precip totals will range from very low to non-existent.

    Starting tomorrow, it looks like we’re in line for 7-10 days of dry but cool weather before–finally–we arrive at a decent chance of a major pattern shift beyond day 10. Long-range numerical progs are suggesting the breakdown of the persistent E. Pac. ridge early during the second week of November, with the potential for meaningful precipitation at least in Northern California and perhaps statewide as a rather strong jet replaces the blocking pattern. Stay tuned–we really need the rain.

  • Nicholas

    As soon as I say that a small jet stream forms right over the area and have been getting some very heavy rain training over the area for the past hour and a half. The sun was out all morning and I just had that felling.

    • Dan the Weatherman

      Only a few sprinkles have fallen here in Orange so far. The activity has been isolated to scattered so far and I hope to see more widespread shower activity later on this afternoon and evening.

  • Ken K.

    We have picked up a decent .67 at the house(Granite Hills) so far this morning. Some heavy showers over night and nice steady soaking yesterday. Bring more on, I am ready for a good wet and cool winter.

    • Shady Blues

      That’s impressive. I would be surprised if I got more than .10 inches. The heaviest cells were to the east of me. Yet again, this storm was biased. in the location of rainfall.

  • Shady Blues

    The subtropical jet-stream looks more active this year. Hopefully, that is a harbinger for a good winter…

    • Well, hard to say anything about what the subtropical branch will do all winter at this early date, but it certainly looks active in numerical model progs for week 2.

  • Nicholas

    Like the Packer season the rainy season is looking up for November if the GFS is right.

    0.40 yesterday for my area.

    • Dan the Weatherman

      I only received .02″ from the storm down here in Orange. There were only a few sprinkles or very brief light showers Monday morning, and a somewhat heavier and longer shower or two overnight last night into early this morning.

      I am really looking forward to some storms that bring more substantial and widespread rainfall instead of this hit-and-miss stuff we have been getting for the last 2 years!

  • Latest model output seriously backing off on potential for pattern change, instead shifting the current West Coast ridge towards the Central Pacific and amplifying it even more (directing the typically zonally-oriented jet over the West Pacific all the way up towards the Arctic Ocean north of Alaska–an impressive feat!). While we’d be on the downstream/backside of this enormous ridge, it looks like a secondary ridge just west of California might act to keep things on the less active side for the foreseeable future. This is a very unstable large-scale pattern, though, and tilted blocks like the ones currently depicted in the GFS solutions are notoriously susceptible to rapid collapse. So…the models could change their tune rather quickly i n the coming days. For now, though, don’t get your hopes up for meaningful precip in the next 1-2 weeks.

  • Dan the Weatherman

    The SFO NWS AFD is mentioning that the medium range models are hinting at a storm that could bring rain to CA late next week. I hope this verifies, as we really need to start getting some storm activity ASAP. I know that is still a ways away, but there just hasn’t been any meaningful rain in sight for months now it seems.

  • Nicholas

    Models are having a hard time with this pattern and it could go a lot of ways. I am in favor of the more wet solution. I still think its going to be a poor winter and in poor winters November can sometimes be the highlight.

    • Dan the Weatherman

      I agree that this could be another poor winter, even though I don’t think it will be quite as dry as last year and I think the heart of the winter (late January through March) will be wetter this time around.

  • Models really are all over the place right now, with the latest operational GFS depicting a pretty dynamic and stormy pattern out beyond day 7. Have to wait and see, I think.

    • Shady Blues

      Indeed..its that time of year again…..6z of the GFS showed a impressive storm in the five day period, but that is now gone. The more recent runs (12z,18z,00z) have the low moving well west of the area.

  • Shady Blues

    Really impressed with the recent GFS run solutions, especially the 6z. A series of strong storms is shown impacting Southern California…something we never saw last year. If models hold true…we are in for a very wet and dynamic periods….but again like what Daniel said we have to wait and see what happens!

    • Wow…those really are some impressive runs. I’m starting to believe that we’re in for a big pattern change in the second half of November–finally–and it recent solutions are anywhere near correct it could result in some very impressive storminess over California. Haven’t seen a longwave setup like that in at least a couple of years…

  • Nicholas

    The most impressive thing about the last few model runs is where that moisture source is coming from. Its been since 2010 that moisture has came from that far south. When you do see moisture come from there with the parent low near the area that does favor some good thunderstorms and it helps we are in November.

  • Models are continuing to adjust to what appears to be a very high energy pattern shift. The large-scale flow and jet stream setup in the 10+ day period is one that has some extreme rainfall potential, but it could manifest itself anywhere from British Columbia to Southern California depending on the actual trajectory. I will say that someone on the West Coast is likely to get firehosed with the mean longwave trough amplifying and retrogressing 1500-2000 miles west of California coupled with a large region of very strong jet level winds. We’re still over a week out, but this pattern bears close watching and I will probably have a full blog update later this week.

  • Dan the Weatherman

    To our luck it will probably hit the Pacific NW and BC given the time of year as they often get a fire hose of moisture in November, and they have been relatively dry lately compared to what they could be getting this time of year. Maybe I am being a bit pessimistic as well, thinking that this fall is going to continue to be very dry in CA like it has been so far up to this point. We will probably get some rain in a good portion of CA later on this month, but whether it is a major event or not remains to be seen.

    • sc100

      I definitely don’t blame you for being pessimistic!

  • New 00Z GFS depicts a phenomenally large and powerful blocking ridge over the Central Pacific, peaking at over 1050 mb!!! California and the West Coast would be well downstream of this ridge, and this is a pattern that needs to be watched very closely given the potential for persistent lower-latitude cyclogenesis in the East Pacific with a deep, sustained subtropical tap. As has been noted earlier, this is still 8-10 days out, but this would be a pretty exceptional pattern. There are currently several tropical systems in the West Pacific that may be contributing to the high amplitude and volatility of the simulated pattern, so solutions could still changes significantly as we move forward. But…my personal opinion is that this is one to watch. Stay tuned…

  • PM Update: All long-range numerical models continue to show a major change towards a high-amplitude, high-energy pattern over the Pacific Ocean beginning next week. Specific placements of relative ridge/trough sequence will be crucial in determining sensible weather outcomes for the West Coast, but there remains the potential for some rather extreme precipitation somewhere along the West Coast at some point during the 8-16 day period. ECMWF and GFS both suggest that a very deep and prolonged poleward flow from the subtropics (tropics??) will develop and feed into any storm systems that develop in the East Pacific during this time frame. Some individual model runs have produced some very impressive rainfall totals anywhere from Central California to British Columbia. Pattern recognition suggests to me that this could be an even more significant setup than current model solutions suggest. Again, patience! We won’t have a good idea how this is going to evolve for a few more days yet, given the extreme volatility of the projected flow pattern.

  • mendodave

    YES!
    Mendocino has had less rain that Death Valley so far this year.
    This is Not Good.

    • I’m not totally sure that’s literally the case for calendar year 2013 thus far, but it may be true for the past ~180 days and is certainly true for the past few months. It’s remarkable that it’s close enough that I even need to check! The January-May 2013 period was really incredible in NorCal–just no storm activity to speak of. That’s not totally unheard of in Socal, but for the northern part of the state it was pretty stunning.

  • Nicholas

    It looks like So Cal could get shafted with the next few systems if the GFS is right.

  • Still enormous uncertainty in the upcoming major pattern change and major spread in solutions between models and even from run to run. Potential is still there for a very large precipitation event somewhere on the West Coast in the day 7-14 period, including California, but anything more specific than that remains speculative at best.

  • Dan the Weatherman

    The weather pattern here in Socal has been quite anemic lately (inactive) except for the beginning of October in which we had a moderate Santa Ana followed almost immediately by our first storm of the season. It doesn’t seem really all that likely to me to go into an extreme precipitation pattern from the inactive regime we are currently in unless we get some stronger Santa Ana winds in the near term or a more changeable pattern beforehand. I just don’t feel that the conditions are right for a major rain event right now, especially considering the -PDO and ENSO neutral situation.

  • ECMWF has a really spectacular storm developing off the West Coast days 9/10, and a fairly impressive “near miss” big storm for CA on days 6/7. GFS continues to be all over the place with this. ECMWF is definitely the better model these days, though it’s more of a toss-up in this situation since the amplitude of the flow pattern is so high. One thing I can say with more confidence at this point is that it’s all going to come down to how close the very deep longwave trough axis is to the West Coast. If it’s within 1000 miles, there is an excellent chance for at least a couple of very strong storms during the second half of the month. If it’s farther west, we could miss out on the most significant storminess, though we would probably still get at least some precip out of that scenario.

  • Nicholas

    It could be November part 2 here in So Cal if the GFS is right. We get skirted with nothing while No Cal gets smacked up. Got to hope that ridge moves in a slightly better spot.

    • Dan the Weatherman

      I am not ruling out the possibility of some rain later this month, but I just don’t think Socal will have a huge storm this month with really impressive totals like the models have been hinting at times lately. The bulk of the rain will probably hit the Pacific NW and possibly Norcal, which would be more in line with climatology this time of year. I think our turn for larger storms will come during the heart of the winter from mid-late January onward, and we are definitely due for some wetter weather late January-March for a change. The last two Februaries in Socal were extremely dry and the heart of winter last winter for the entire state was absolutely abysmal to say the least.

  • Dan the Weatherman

    The Santa Ana winds didn’t come up today nearly as strongly as forecast here in my area of Orange, as it was only breezy. It was definitely warmer today than it was yesterday with highs in the mid-upper 70s. The forecast is for mid-upper 80s tomorrow with some Santa Ana wind gusts up to 30 mph below the canyons and passes, but since the winds were lighter than that today and the second day’s winds are usually weaker than the first, I don’t really feel that there will be that much wind here tomorrow. It will probably be warmer than today, though, as it usually is in the waning hours of a Santa Ana event.

  • Tom in San Diego

    060559ZNOV13/6Marcomsat2638///////4//////
    Pretty quiet over here right now. Typical autumn day in Yokohama this past Sunday, temps in the low70’s, expect wa2mer but cloudy in Taiwan tomorrow. Typhoon east of central Philippines could effect things this coming week from Sunday on, have to wait and see. Had a cold rainy crossing, by and large, temps in the 40’s and 50’s. cleared off nicely once south west of Dutch Harbor n the Aleutians.

  • Dan the Weatherman

    Latest excerpt from SFO AFD:

    THE MEDIUM RANGE MODELS AGREE THAT AN UPPER TROUGH WILL DEEPEN OFFSHORE ALONG 140W OVER THE WEEKEND. THAT SYSTEM IS FORECAST TO TAP INTO A RICH SUPPLY OF MOISTURE FROM JUST EAST OF HAWAII AS IT BEGINS TO LIFT TO THE ENE EARLY NEXT WEEK. ACCORDING TO THE LATEST MODEL OUTPUT…PRECIP WILL FALL ACROSS MUCH OF OUR AREA ON MONDAY NIGHT OR TUESDAY OF NEXT WEEK AS A WARM-FRONTAL BOUNDARY APPROACHES THE CA COAST. HOWEVER…THE SURFACE LOW IS FORECAST TO LIFT ALMOST DUE NORTH WELL BEFORE REACHING THE COAST…AS AN UPPER RIDGE OVER BAJA BEGINS TO BUILD NORTH. SUCH A SCENARIO WOULD DIVERT MOST OF THE SIGNIFICANT PRECIP TO OUR NORTH EARLY NEXT WEEK. THE 00Z GFS THEN BUILDS AN UPPER RIDGE NEAR THE WEST COAST DURING THE MIDDLE PART OF NEXT WEEK…SIMILAR TO WHAT THE 12Z EURO IS FORECASTING. THIS IS A MARKED DEPARTURE FROM WHAT THE MODELS WERE SHOWING AS RECENTLY AS YESTERDAY. IN FACT…FOR THE PAST SEVERAL DAYS THE MEDIUM RANGE MODELS HAD SHOWN A WET AND COOL PATTERN FOR OUR AREA BY THE MIDDLE OF NEXT WEEK. NOW THEY SHOW WARM AND DRY.

    Aside from possibly some rainfall in Norcal on Monday or Tuesday, it is looking more likely to remain drier than average for at least a while longer in most of CA, unfortunately.

    • Dan the Weatherman

      When I was mentioning the positive phase of the AMO earlier on and its possible effects on our weather patterns, I forgot to mention one important thing. The time period from 1945 to 1963 featured the combo of -PDO and +AMO for the most part, and according to rainfall records for downtown Los Angeles since 1877, that was overall the driest time period of the entire period of record for that station. This is the reason why I am thinking that the positive phase of the AMO may be amplifying the dry signal of the negative phase of the PDO somehow, but I don’t have enough understanding of the oceanic circulation patterns to try to explain it. When the PDO is positive, it seems to not matter what phase the AMO is in, as CA can have really good rainfall seasons during both -AMO and +AMO regimes, even during ENSO neutral. Please note that I am writing this from a southern California standpoint, and the results may be different in Norcal as I haven’t studied the precipitation records for San Francisco like I have for Los Angeles.

  • Well, those model solutions sure have changed a lot in two days, and both of the leading global models (GFS and ECMWF) have been equally inconsistent. That extremely high amplitude flow pattern may end up being just be too far west to bring much rain, even to NorCal! This is one of the more impressive reversals I’ve seen in some time. Perhaps it will return; perhaps not. But it’s now November, and if we go another week or so without significant precip the deficit for the new 2013-2014 water year will already be significant. Let’s hope for another wild swing back in the other direction…

  • That model change is pretty abrupt and dramatic. For the East it showed variations of a snowstorm in different areas, and here in Vermont an article blast the likes of which we haven’t seen so early in the year in a while. It’s a huge change though. Not ready to jump on it. I really hope ca gets some rain soon.

  • alan

    Did someone use the word ‘obliterated’? Any chances of rain south of the Bay Area have all but been obliterated for the next two weeks….sad….hope it changes back for at least the 7-14 day period and beyond…..bored out of my mind with the weather lol…..

  • This fairly stunning reversal may have something to do with Supertyphoon Haiyan in the West Pacific, which (with sustained winds around 200 mph!!!) is now one of the strongest tropical systems in recorded history anywhere in the world. This system is no longer expected to eject into the Westerlies; while the models just a few days ago integrated this possibility and developed extreme blocking over the Pacific, that’s no longer happening. Hmm.

    The GFS and ECMWF now both suggest November could be a pretty DRY month in California. Not at all what we needed…

    • Dan the Weatherman

      Is it my imagination, or are we experiencing a more active typhoon season (strength of storms and numbers of storms) in the Westpac for this time of year? I know that some typhoons always form in the region during October and November because they often influence the storm patterns on the west coast during early to mid fall, but lately this typhoon season has seemed hyperactive to me.

      • Unlike the Atlantic basin this year, the West Pac has been very active, with a large number of cat 4/5 systems. While typhoon season is technically year-round in that part of the world, there is often a late summer/early fall peak.

  • alan

    Hurricanes – who canceled hurricane season…

  • alan

    At least the 18z brings back a SoCal storm on the 17th with hints of storms beyond that…..

    • I dunno. The pattern doesn’t look especially promising, despite the depiction of some modest precip. Perhaps solutions will start to converge once this supertyphoon is out of the picture in a few days…

      • Dan the Weatherman

        Maybe the models will start coming into better agreement as long as another strong or super typhoon doesn’t develop behind it to take its place. I would think after a while, all the upwelling of cooler water from all these typhoons would make conditions a bit more unfavorable for this almost continuous tropical cyclone development to continue and the activity would then slow down at least temporarily.

  • kcanton40

    Hi Dan,

    I’m getting somewhat nervous about the 2013-14 rainy season here for Ca. Here we are in Nov and the state still has not received any significant precipitation. The fact that we are still stuck in the -PDO, -NAO, with a neutral pattern developing again this year does not really help. I tend to agree with you from your previous post in the past. What is even more interesting is the data you’ve provided which we were in a similar Oceanic pattern set up from 1945-63(18yrs!) and So Cal had lower than avg rainfall overall during those years. Perhaps, we can do research and see if Nor Cal had similar deficits. It looks like the rest of Nov will be dry or with below avg precipitation. We still have Dec-Mar which the state receives about 80% of its annual precipitation. Have been reading the Tahoe Daily Snow reports, Dave mentioned that he believes that things will not really get going for us until after mid Jan 2014 which I think is pretty late in the season for us. On the other hand, in your estimation when can we expect the -PDO to flip?? I think it started back in 1995. I think when that happens we should start seeing some pretty good rain/snow years again for the state.

    • Dan the Weatherman

      The PDO flipped negative in mid-1998 and then went neutral to positive from mid-2002 until late 2006 when it went negative and fluctuated between positive and negative for much of 2007 until going solidly negative in the fall of 2007, and has been negative since except for a positive period in 2010 with the 2009-10 El Nino. The AMO flipped positive in 1995 along with the uptick in Atlantic basin hurricane activity and has remained positive since. I think it will be a while before the PDO flips back to positive, but I am hoping the AMO goes negative soon since it has been positive for 18 years now. These cycles can last up to 30 years, but that doesn’t necessarily mean that it will continue for that long this time around.

  • kcanton40

    I meant Bryan Allegretto, not Dave for Tahoe Daily Snow reports. His analysis is very accurate too much like Howard Schectner for Mammoth Mountain reports. Howard even recently said in an email he sent me that because of the -NAO phase that it could be the “kiss of death” for our rainy season even though the QBO is in its positive or Western Phase compared to the last 2yrs; only time will tell. You have been very consistent in your prediction so far for this year as I’m learning how all of the global tele-connections affect the weather patterns, especially for the West Coast.

    • Dan the Weatherman

      The -NAO pattern typically occurs when the Greenland block (high latitude blocking) sets up and a deep trough forms in the central and eastern U.S., which usually leads to very cold air and snow in that region. Many times, a +PNA pattern occurs during the -NAO, in which a ridge builds in the eastern / northeastern Pacific, blocking beneficial storms from coming into CA.

      It would be interesting to find out if Sacramento and San Francisco have had similar rainfall deficits as Socal during the -PDO, +AMO regime that I mentioned above. If you would like to research that, feel free to do so.

  • kcanton40

    Yes, based upon my research, the avg precipitation for SF, Ca from 1945-63 was 20.30in. I think the avg annual rainfall during that time frame for the city was about 19.30 in. But, today it is 23.80in because we had a lot of wet years during the 1990s. I see that indeed there were more drier than normal years, with only a few very wet years in between when we had the -PDO, -NAO, and neutral ENSO combo. You can go onto Jan Null’s website, http://www.ggweather.com to learn more about Nor Cal rainfall patterns. Jan Null has always been a well informed and knowledgeable weather expert for many years here in the S.F. Bay Area. I really do hope that we see a flip in the global teleconnection patterns so the state will get decent rain/snowfall again. I do think this first part of the rainfall season will continue to be drier than the long term avg and we will make up for it starting late Jan and beyond; therefore we should not be as dry as we were last year, but overall we may end up still below the long term avg for the state.

    • Dan the Weatherman

      That is certainly interesting that you did find more below normal seasons for San Francisco during this time period, although they were likely not as dry as Socal due to being further north (higher latitude) with higher precip averages and closer to the storm track that has been displaced northward.

    • sc100

      Looking at Sacramento’s records from 1945-1963, most of the years were below average as well. Only 4 years got above 20 inches (which is around average for Sacramento). One of Norcal’s biggest floods (1955) did happen during that time period, however. Looking at a longer time record, there was a drought for 20 years from 1914-1934 (no year above 20 inches), then 8 years of good rain from 1935-1943 (every year but one was around 20 inches or higher!) then a seven-year drought from 1944-1951. Good years started to become a lot more common after 1967 and that trend continued until 1986, before California’s 7-year drought began. And of course, the rest of the 90’s were by and large amazing years (which is when I got interested in weather).

  • David

    Daniel i think you are right i think onces are supertyphoon is out of here i think are weather will turn wet and if the 06z are right that may happen has soon has 180hr

    06z 1t it was really good 1st storm comes in at 180hrs a beark on sat be for the next storm comes sunday in too tusday with snow levels down too 4000ft or lower a break on tusday with other storm on wed a break on thursday with a other storm come that following weekend not has cold looks like snow levels 5000 too 6000ft with that storm wish is all so thanks giveing weekend

    • I’m starting to feel pretty pessimistic about this month. We’ll probably get some rain, but given the recent evolution of the previously-projected major pattern change in the models and the new-found persistence of the East Pacific high, I’m leaning toward below to well-below average precip for the month on the whole (first week was bone dry, and second week probably will be too outside of far NorCal). I’ll do a main post wrap up this weekend even though there’s not too much interesting going on after all…

  • Nicholas

    Has Sacramento ever had an October/November shut out for rain?

    • sc100

      There have been Octobers without rain in Sacramento (like this year) but they don’t happen that often. There have only been 5 Novembers without rain in Sacramento history, so that’s really rare. The last time that happened was 1995.

      • Dan the Weatherman

        Can you list the other 4 Novembers without any rain in Sacramento? I am just curious when they occurred so i can try to figure out what regime they occurred in.

        1995-96 was a +PDO, +AMO, weak La Nina year that featured a lot of cold weather in the Midwest and east. Socal had a very dry fall much like the way this year has been so far, and turned wetter in mid-late January, and especially February, and then with a few storms in March and possibly April.

        • sc100

          The other 4 years were 1884, 1890, 1929 and 1933. The 1995-1996 water year actually ended up above average for us and we only had .01 inches by December 1st! I remember that huge cold snap in the Midwest in 1996. Got down to -60 in Minnesota. I don’t think they’ve had a cold snap that bad since.

      • redlands

        At my station In Redlands, Ca – My rain records back to 1981. There have only been 2 Novembers that have been rainless — Nov 1992 and 2005 . November 1999 had 0.05 November 1995 and 2006 had 0.06. Average rainfall for November at my station is 1.02 — October average rainfall is 0.59 .

  • Tom in San Diego

    090124ZNOV13/0 MARCOMMSAT/WXJR4657
    Im sure you guys have heard by now typhoon Haiyan has crossed the RP, luckily in the less populated middle islands, from Samar to Masbate, but still with lots of damage and untold loss of life yet, that word from one of our sister ships in Davao this morning. Our thoughts and prayers certainly wouldn’t hurt. Its headed for Viet Nam at present, likely regathering some strength now on the open water in South China Sea.

    • Nicholas

      The situation is getting very little attention. We will keep the members in our prayers Tom.

      I hope that all this blocking leads up to a huge December cold snap. It does not look much like fall here in Whittier. It looks a more like late April.

      • Dan the Weatherman

        It does appear that the major cities avoided a direct hit, but that is not to say there wasn’t a lot of damage. From what I heard in the news (Anderson Cooper on CNN), a storm surge of 40-50 feet swept across the area where the strongest part of the storm hit and an airport in that area was completely destroyed. Hopefully people living in the area were evacuated to higher ground with some protection before the storm hit, or there is likely going to be a very high loss of life.