Thursday, December 23, 2021

Pathetic weather continues unabated

 I'm now pretty confident of the cycle length of this years weather pattern which started setting up in early October.  Results of sensible weather (what to expect for you and me) will be different during the fall and spring verse the driest part of the year - Winter.  It is still unknown what part of the weather regime across the northern hemisphere is "forcing" the pattern itself, and what if any changes will occur going forward.

I'm sure most of you have heard that we are in a second, back-to-back La Nina pattern and it is actually bordering on a moderate event.  Looking at composites of previous La Nina winters from history does not support what is going on across the west, especially the southwest part of the country.  For the high plains of Texas, Kansas and Nebraska (and of course eastern Colorado), the composites of years past have been all over the board from wet to dry and from cold to warm.  Obviously at this point our region has been in the "warm and dry".  Will this continue?  If only I knew but unfortunately question is very complicated.

Recently I believe the Madden Julian Oscillations (MJO) has been calling the shots.  A fairly robust MJO across the western Pacific (phase space 7) has stalled.  Looking at composites of previous MJO events across the that part of the globe for December has yielded dry but increasingly cold.  Here is a look at the current chart of where the MJO is and where it is expected to go....

In that previous post (click here) I had mentioned the brutal winter conditions that had been stuck across the other side of the hemisphere (Siberia and Europe primarily).  A severe energy crisis is ongoing in that part of the world.  In that previous posting I saw hints that some of this cold could impact our area late December into early January.  That seems plausible as the MJO location is favorable and the Arctic Oscillation Index has gone sharply negative (usually when this happens cold is dislodged towards the equator).   This morning some really cold air was in place across Canada.

Based on the cycling nature of the weather pattern, any really cold air that moves into the high plains might not last too long (a week to 10 days).  Again, the target date is the last few days of December and into the first week of January.

As far as significant precipitation - at this point for the high plains it does not look favorable.  Yes, there could be some with the cold air but I'm afraid that anything meaningful may not materialize.  I'll address that later.  We could really use something.  For the past 60 days, here is a look at how much has fallen - or not even occurred.

And as many are aware, this dryness this past 60 days has contributed to the drought conditions (and it happens more slowly during the dry winter months...

The jetstream as indicated on this map.... in a perfect position to bring wetness to the western U.S., including the arid southwest and into the Colorado Rockies, but is NOT favorable to bring meaningful precipitation to the high plains.  The pattern is just too far west and too progressive (systems are moving across the central U.S. too quickly to draw up moisture).

So, for January and February, at this point, I don't see a really wet pattern developing.  We might get lucky with a storm or two close enough and slow enough to bring at least something.  But enough to make a dent into the drought just doesn't seem to be in the cards.  This will be REALLY bad for fire concerns as there will be those periodic systems with a lot of wind and unfortunately there is a lot of fuel (grasses) present. 

As another cycle of this weather pattern transpires, I hope to have a little more confidence going forward.  More later...

Friday, December 10, 2021

This is complicated and where did my post go?

I went back to look at the previous post I did on December 1st and I can't find it!  Well crud - I bet I didn't save or publish. So - it's been a while.  On that last actual posting on the 19th (Nov), the theme was trying to figure out the cycle length of the newly developed weather pattern and impacts.  I'm puzzled.  This one is not easy to analyze (well it never is, but some years it's a bit more clear).  Last year the pattern was reoccurring somewhere between 45 and 47 days.  This year it may be much longer!  There are conflicting signals.

For those that may be relatively new to this blog...

Weather patterns that exist and cause various types of weather across the high plains, develop and establish every fall and every year are different from the previous year.  The results can be the same, but the actual pattern that produces the weather will be different.  Unfortunately for the high plains, weather is heavily influenced by the big rock pile to the west (Rocky Mountains) and influenced by the availability of gulf moisture.  Geographically the high plains is located in a semi-arid region (some years wet, some very dry, others in between).  Look at variability of yearly precipitation (in this case Dodge City)....

There is tremendous variability from year-to-year, let along variability on a very small scale with regards to precipitation patterns even when a weather regime is similar (not the same though).

I've been to several meetings this past month and have hinted pretty hard that December could turn out pretty cold but that was based on a hunch and analysis of where the early buildup was occurring.  The airmasses that would support a cold December have definitely been in place, but on the other side of the hemisphere!  

I'm sure some of you have heard news reports (if they can believed - I know it's hard).  The ice build-up at the higher latitudes oceans and waterways was strong and early.  See my last post I did (that was published) back in November at  Europe and Siberia have been hit particularly hard with the cold that has now produced some energy shortages - ALLREADY!  But why hasn't that cold been displaced towards our neck of the woods?  Well, to get that to happen the atmospheric river of air above us (the jetstream) will have to become oriented in such a way to deliver the cold south into North America.  Very recently the cold has spilled across the eastern Pacific.  The higher elevations of Hawaii was hit hard with blizzard conditions while the lower elevations got pounded by excessive rainfall. 

A slight shift in the flow was now occurring producing an onslaught of rain and snow due for the western U.S., and finally some decent snows for the Rockies. Look at how much precipitation is expected during this next 7 days (through the 17th)....

This similar situation occurred around mid-October.  Unfortunately that is a lot of "white" of no precipitation for the central and southern high plains.  The weather system moving through today (Friday) and the one during the middle part of next week will produce nothing but WIND.  

So is there any hope for precipitation beyond this period?  Computer models that go out a ways, and often with many errors, are all over the place.  Most of them keep the weather dry with little to nothing and some even keep it dry on through all of  December! However, every couple of days, one or two "hint" at some decent precipitation.  Those infrequent computer "runs" that have precipitation just might be the reason that some recent outlook maps from the Climate Prediction Center look similar to this...

No one should get excited by this.  First, this is a probability of leaning towards above normal precipitation.  It doesn't imply a "lot", just that the odds have been shifted towards the above category.  Anything would be nice at this point.  Again, computer forecast models have been all over the board with the majority pointing towards continued dry.  However, looking at the cycle length of returning weather systems, I do see at least a small chance (at this point) of something between December 18 and 21.  That would simply be a "finger crosser" for now.  A lot of changes would need to take place first so I'm not terribly optimistic, but still slightly hopeful.  If that doesn't pan out, it doesn't look too good going into the first of the year.

As for really cold air?  Yeah there is some hint for later this month and into the first week of January but I need to analyze that length of returning systems.  I'm kind of fearing that the ocean temperatures of the equatorial Pacific may be the biggest contributor of the current weather pattern across the Northern Hemisphere.  Why would I fear that?  Because of similarites from the past.  In example, the fall and winter of 2009.   I'll address that in the next posting - and I'm going to attempt to do that next week.