What’s ahead, way ahead; some excitement for the West Coast

Been working on a talk for Feb 23, 1990…..at the U of WA, so not blogging too much.  Will likely post “back to the future”  talk in a few days.  Its a science story, really, not quite a “talk.”

But enough of my blabbing, as Rob Reiner might say,  lets move along to some INTERESTING spaghetti.

First of all, things rolling along pretty much as foretold in spaghetti at our last meeting,  a week or so ago.  Storms are rolling in on schedule now.  Had 0.50 inches in the first one, here in Sutherland Heights.

Below, is the five day from now spaghetti or Lorenz plot.  You may recall,  though I doubt it, that spaghetti was foretelling a big ridge that would break off into the Arctic and help shunt storms into Cal and the West Coast.  Valid 5 days from now, to repeat.

Well, that was spot on because it is going to happen after a little break from the current storms.  Of those,  the rainiest one for us is tomorrow and the next day.  Likely to see an inch or more here in Sutherland Heights from that one storm! Looks like a quarter of an inch will be the total for the current one.

All this is so great for the spring bloom, too, that time of year we all love.

But enough of my blabbing #2, as Rob Reiner might say again,  lets move along to some INTERESTING spaghetti.

The weather pattern way ahead

But the real news I wanted to inform you about through excessive speculation is the spaghetti plots for about two weeks out, shown below. This ios amazing in my view.

I wonder if my one reader can detect the amazing part?

Ann2 spag_f360_nhbg

Its the grouping of the blue and red lines in the eastern Pacific that seems extraoardinary in a plot like this where “chaos” usually rules in this sector THAT far away in time.

Here, the grouping of red and blue, a coming together which can never happen in the political color realm, means there is a very strong signal in the measurements. The slight errors input at the beginning of the model runs leads to close to the same forecast even 15 days out!

So, what does it all mean?

This is no doubt in CMP’s mind that this strength in a medium range forecast is due to the constraining of weather patterns by the Big Niño now in progress. That feature is keeping the jet stream constrained to bash the West Coast and Cal, and that’s what you get out of this plot above. Very strong storms are now setting up to bash the West Coast, ones associated constrained to do so by the powerful El Niño.

The current storms, as you likely know from media weather folk, are classic in their El Niño appearance, streaming into Cal and AZ at lower latitudes out of the Pacific. So far this winter, in Cal and AZ, we haven’t seen much effects of a Big Niño until now.

That 15 day spaghetti plot is not one that we here can pin confidence on about a lot precip, but hang on in Cal, especially beginning about a week from now when this pattern really sets up and then crescendoes.

Below, just decided to add the 10 day spaghetti, kind of out of control due to excitement. The bunching of red and blue contours is astounding to me in this one, that in the east Pac resembling that of the geographically-forced bunching we see all the time in the extreme western Pacific off China.  This bunching, with a dip to the south (trough) off the West Coast indicates a very reliable forecast of a huge trough bashing the West Coast about then (Friday, 5 PM AST, Jan 15th).  Maybe, just MAYBE, those Cal reservoirs WILL be filled up in a single winter!spag_f240_nhbg

The End.

4 thoughts on “What’s ahead, way ahead; some excitement for the West Coast”

  1. Hi Art: When you say these storms will be hitting the West Coast, just how far up the coast will they impact? My latitude? So far, this has been a quiet January here. Just wondering.

    1. The specific positions of the storms vary from run to run, but the general pattern predicted in that 1-15 dya window I was discussing seems locked in. In one run, a very intense low passes right over Vancouver, CAN, in that window, However, the heaviest rains would be well to the south of you, if my interpretation turns out, would mainly be in OR and CA.

      a

  2. Oh, heck. I probably should spend more time. I used to spend more time on those wild plots, but have shirked some of that lately since I felt I would be repeating some things, and was lazy, too. Just wanted to “get it out there.”

    The thing is, with the far more capable computers we have, instead of taking hours to run a forecast model, it takes far less time, and many more of the SAME model can be run.

    We know that no measurement is exactly correct due to measurement error bars in everything; wind, temperature, humidity, etc. We also know that tiny errors can add up to large differences over time: the Lorenz “chaos” effect.

    But, until lately, we haven’t been able to do more than run the model with the obs its been given, tiny errors, sometimes larger ones, included. Sometimes, even good measurements are thrown out if they deviate too much from what’s expected by the prior model run! Say, a storm center was much deeper than progged.

    So, what’s our answer, knowing the data are full of little errors, and having gigantic computing capability?

    Run the SAME model but with slightly different initial conditions, inputting slight differences in the obs.

    As you can see, (http://www.esrl.noaa.gov/psd/map/images/ens/spag_nhbg_animation.html)
    slight errors have almost no impact whatsoever in the first few days of a model run, but as the model gets farther away from t=0, the differences get larger and larger, and finally you can end up, as these plots of just a couple of contours aloft show, a “bowl of rubber bands”, lines (contours following the jet stream along), going all over.

    This ability of being able to run the model(20 or so times in real time almost), is considered a tremendous forecasting breakthrough. You can now also get a spread of the precip at a location based on these model runs now, something I haven’t really explored yet.

    The exception to this in the, say 10-15 day forecast range, is when there is a strong signal, a trough, the circulation situation is so powerful, “constrained” you might say, that the wandering lines (contours) on the spaghetti plots are bunched together much more than usual. The small errors introduced at the beginning of the run don’t make a lot of difference 10-15 days out. The “Frankenstorm” during the Niño of January 2010 that hit California, setting low pressure record at San Francisco, was a storm that was, as the NWS wrote, well-predicted ( by bunched lines, to be colloquial about it again) in the “ensembles” or spaghetti plots. That storm, as it trudged across AZ, brought over 3 inches of rain here to Catalina in two days.

    So, well bunched lines in the 10-15 window of the ensembles is situation that seldom occurs, and that was what I was excited about yesterday. They seemed more bunched than usual in that time frame, indicating a more reliable forecast than usual.
    I guess we’ll see.

    I haven’t looked today, and, in fact, since I am distracted with something else, might not write again for a few days about this stuff.

    The strongest constraining feature for the jet stream and storms in the whole northern hemisphere in winter is the continent of Asia, bounded by warm western Pacific ocean water. That constrains the jet stream to the same location day after day in wintertime. Errors have little effect on where it is. Its the tail that wags the dog of the rest of the Pacific. Little errors in that zone, lead to larger and larger wandering of the jet stream as time goes on, as an example.

    Today we got us a Big Niño in progress, and I just got confirmation from my friend and Niño expert at the SW Fisheries in Monterrey, (recently interviewed by CBS) that our Big Niño is likely playing the role of a “constrainer” of the jet stream across the central and eastern Pacific.

    Instead of the jet meandering as usual, all over the place, and those little errors making a mess out of trying to see what’s going to happen in the 10-15 day range, it was more compacted, not affected by the initial tiny errors in the ensemble plots I showed yesterday, cause for excitement. Tiny errors? Wasn’t there a song about that by Don Ho?

    a, trying to be intelligible.

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