Wednesday, November 30, 2016

Updated 11/30/2016 This pattern is ridiculous!

In the previous post I did a week ago on the 23rd (click here to read it), I  discussed AGAIN about the Facebook poster out of Oklahoma.  He is still at it and out of control.  Look, he posts NOTHING but computer output from the Global Forecast System computer model.  ALL computer models will vary from run-to-run (at least every six hours) and sometimes dramatically!  This fall, so far, these computer models have failed miserably in predicting even the location of the jetstream (location and intensity), let alone details of precipitation (including snowfall) and temperatures, which cannot be predicted with any degree of accuracy beyond a couple of days.

This has been a really tough pattern to nail down.  There has been so much cold and snow across Eurasia and Sibera.  I mentioned in the previous post that eventually that cold would slosh back to our side of the hemisphere.  That is starting to happen, which I will discuss below.

In the previous post I said "The one for the end of the weekend is ALSO on schedule but it looks like mostly wind as it will follow suite and track too far north.  There are other possibilities by Tuesday and Wednesday. There has to be some development in the flow aloft to bring any threat and I will discuss the possible development below."

The storm for the end of the Thanksgiving weekend was right on schedule and for the high plains, unfortunately, it did bring mostly wind (and a lot of it)!  There was some light rain but it did virtually no good as it warmed up and got very windy by the end of the day Sunday.  This is NOT a good trend and something I'm watching very carefully!  

The other possibility I discussed (Tue/Wed) also was on schedule but brought very little again to the plains. There was very heavy snow across the Dakota's and sadly killer tornadoes across the southern U.S..

It is very discouraging to have so many systems this past 2 weeks come through with very little in the way of precipitation and so much wind.  Plus, no really cold air, at least yet.

So now what?

I ended the November 23 post with "Active and sometimes stormy weather should be expected for the first 1 to 2 weeks of December. " and that still looks on track.  The pattern is starting to show signs of repeating from where it developed.  That is to say there should be some amplified systems during this next couple of weeks.

BUT....

Looking at the latest satellite image...

click for a larger map


The red X over eastern South Dakota is too far north to give the high plains any precipitation and it was moving away.  More importantly was the big blue H over central Canada.  It has blocked any storm from moving through but actually is in a position to allow cold air to spill into the states.  The only problem is there is very little cold air, yet!

The red X near northern Washington is our next weather maker.  But there is a huge problem!  Because of the blocking across Canada and ridging across the northern Pacific, it looks like this system will drop due south and perhaps all the way into southwest Texas and then turn due east!  That is too far west and south for the plains to benefit!  This would bring heavy rains to central and eastern Texas and the lower Mississippi Valley by the end of the weekend leaving much of the high plains high-and-dry!  Confidence in this is reasonably high in that scenario but there is still a very small outside chance the system wouldn't drop that far south.

It also depends on any upstream storm that could "dig" into the west kicking the first system out sooner.  There was at least one system that could do it (not shown on the map).  Also that particular storm has  a very small chance of developing enough to bring some precipitation to the plains about Tuesday or Wednesday.  Don't count on it, regardless of what you might see from some outlets.  

The upshot is I have extremely low confidence and unfortunately at this point have a very pessimistic outlook for any of these systems benefiting the high plains.

The Weather Prediction Center from the National Weather Service offers the following possibility for moisture during the next 7 days.



At this point, the only advice I can give is to not expect much across the high plains during the next week to 10 days.  But there is a small chance; just hope and pray.  The cold air that is sloshing over into our side of the hemisphere is already impacting Alaska and northwest Canada with some brutally temperatures.  Eventually (maybe by December 10-12) this will cut lose into the central part of the U.S., at least for a brief visit.

I hope to be able to update this blog by Sunday, so stay tuned.

Wednesday, November 23, 2016

Update 11/23/2016

Viral posts from sources you can't trust. It pertains to weather AND news!  I'm sure some of you have been reading posts from the person on Facebook down in Oklahoma.  He claims to be a degreed Meteorologist so a lot of folks take to heart what he has to say.  Don't get me started...UGH! 

Anyway, as I've stated in the past, computer forecast models sometimes fail at 12 hours, let alone 300+ hours in time.  Details of elements such as snowfall or accumulated precipitation on a spatial scale and time scale (even within 12 hours) are just numbers.  There is NO predictability of such.  If you see it, ignore it.  So what this guy on Facebook shows you is nothing more than computer output that will, and often does, change dramatically every time the forecast model is run (every six hours).  No doubt that once in a while the forecast model will be really good and close with those details!  But that is just pure statistical luck.

In the post I did on the 17th (you can read it by clicking here) I discussed several potential storms.  The first system was going to bring mostly wind to the high plains.  Oh boy.  Did anyone see the downburst video I posted on the NWS Facebook page that was taken in Sublette?  That was a dramatic example of a downburst from an elevated thundershower (there was some lightning and thunder but hardly any rain).   Click on  downburst to see it.

The second system I discussed was expected Monday or Tuesday.  It was right on time and brought rain to northern and eastern Kansas and some rain and snow to eastern Colorado.  But for the majority of the high plains of Kansas and down into Texas....nothing (went too far north).

The next system I discussed was due around Thanksgiving or the following day.  It also is on schedule (shown on the satellite image below).  But it is too weak and too far north to bring anything to the high plains.  It will bring a little snow to parts of the Dakotas.

Then I wrapped up that last post with the following: "Yet another system will be possible by the end of Thanksgiving weekend and perhaps the biggest threat another around the 1st or 2nd of December! Details are highly uncertain at this time.  The point is the pattern is finally getting active and should stay that way into early December.  Hopefully at least one of these systems will benefit the plains with decent moisture.  Temperatures will be more seasonal and at times quite a bit below normal."

The one for the end of the weekend is ALSO on schedule but it looks like mostly wind as it will follow suite and track too far north.  There are other possibilities by Tuesday and Wednesday. There has to be some development in the flow aloft to bring any threat and I will discuss the possible development below.

First - the west Pac.
 

There was (and has been) a response from convection across the western Pacific Ocean area.   There still is a transfer of latent heat energy into the mid-latitudes (the green arrows pointing up and to the left).  Also, some of the very cold air across Siberia has been moving east across the northern Pacific. There are other things going on but this should all point to some downstream amplification.  Also, the red X is not a typhoon but is at least an organized system.  Usually something in this position as it moves west and north causes amplification too!

Closer to the states:

(click for a larger image if you would like)
 
There was a vigorous storm across the Gulf of Alaska with upstream ridging of the upper wind flow.  This storm should pound the Pacific Northwest.  There was also significant ridging (moist upper flow moving north) west of Hawaii.  This I find rather interesting.  I'm not totally sure how that might come into play but I think it will.  I'm going to watch that for a few days.

Over the conus:

(click for larger version)
 
 
The red X over southeast Minnesota is what brought some precipitation to the central part of the U.S. late Monday and yesterday.  It had weakened considerably.  The other red X over central California is the Thanksgiving system that will mainly impact the Dakotas.  Part of the issue with that system is the HUGE blocking high (the blue H) over southern Canada.

In that post I did on the 17th, I discussed the North Atlantic Oscillation (NAO) as being one of the keys that might help the upper flow buckle and become stormy across at least the central U.S..  I was looking for the index to go negative (and it has been forecast to do so with a degree of error).  Here is the latest:



It has reached a neutral index and is still expected to go slightly negative.  That "might" be enough to contribute to some blocking and amplifying of the pattern but combining with the current state of the flow across the Pacific "will" make it happen.   That Arctic Oscillation (AO) index continues to be negative and is expected to continue.  This is in spite of an anomalously warm high latitude Arctic region:



Speaking of the Arctic.  The average daily temperature in the band between 90 degrees (north pole) and 80 degrees north has been "off the chart" above normal.  I've never seen it like this!