Wednesday, April 22, 2020

Update - April 22, 2020

So...remember the dates I threw out there about April 21 and 22, starting in the post I did on February 27?  In the previous post last week (April 14 and you can read that one by clicking here), I wrote that all the long range forecast models had shown absolutely nothing for the 21st and 22nd and that was only 7 to 8 days away! Today is wrapping up a couple day storm.  Although some areas didn't get a whole lot of rain, there was quite a bit of the mid-southern high plains that got widespread 1 to 3 inches rain!  Here is the map but it is only up until 7 AM this Wednesday morning so won't count what fell today....

In the previous discussion with many of you about that 21st/22nd period when I made that prediction back in February - I had my reasons of timing and pattern recognition.  At that time I thought that if everything panned out, then with the expected weather pattern for the time period in April, there should be severe weather (blizzard in the cold sector).  But as it turned out, deep boundary layer moisture for this storm was hard to come by (given the really cold regime around Easter that shut everything down into the gulf).  There was severe weather, but south of Kansas.  Here are the reports from yesterday morning through this morning....

If deeper and richer gulf moisture had been in place, I feel strongly that we'd be talking about very widespread severe reports in addition to flooding rains.   

So why did long range models even 7 days out fail to pick up on this storm?  It's because there are so many variables that models just can't accurately account for everything in the atmosphere.  Plus, there is too much feedback in the atmosphere that an accurate forecast from a model is often not possible.  Even on a very short times scale, computer forecast models are not that accurate, many times.  As an example, the next 3 images show various short range computer models and their quantitative precipitation forecast for Dodge City.  The models were run less than 6 hours apart in time.

Forecast number 1

Forecast number 2

Forecast number 3

For several days they had shown 1.2 to 3.0 inches of rain in Dodge.  We got only ~ 1/2 of an inch.  But, south of here only 20 miles it was closer to 1.5 to 2 inches.  So, a shift of the small of a distance was the difference.  If a short term high resolution model can't get it right at a specific point, how in the heck can we trust long range models many days to weeks in advance?  For me, it's showing trends and hedging what direction to go (precipitation and temperature anomalies).

Going forward....

Looking at the satellite image from earlier today

The main system was moving out of the area.  In the flow aloft, there was a weak disturbance observed across Oregon.  That could help bring widely scattered showers or storms tomorrow (Thursday).

But, based on the pattern that developed during the early fall, the area should go through a relatively dry spell - but warmer too!  Vegetation should really start to take off!

Here is the outlook from the Weather Prediction Center for possible precipitation through early next Wednesday (29th) which should include what falls (Thursday-early Friday)….

I did mention in the previous post that if any frost or freeze were to occur again for this spring, it would be between May 1 and May 6 (and a light freeze or frost).  But I gave that a very slim chance (5-10 percent).  I still see that possibility, especially farther west near the Kansas/Colorado border and into western Nebraska.  Pinpointing more specifically it looks like May 5-6.  In addition, around that May 5-6 period will probably be the next chance for widespread precipitation (but probably severe thunderstorms before the brief colder weather makes a brief appearance).

At this time, I'm looking at the period from around May 10th through the 28th to be particularly active. More on that later.

Finally, I'll leave this date to ponder.  June 18-19.  Mark it on your calendar.

Tuesday, April 14, 2020

Update - April 14, 2020

In the previous entry that was done March 27, I had a discussion about more cold.  For some reason, many people (experts?) were in discussion about the early spring and likelihood that severe cold was over.  In that March 27th posting, I wrote that it was way too early and that I was very confident of well below freezing temperatures occurring again, several times, for much of the high plains.  Hopefully the cold that occurred this past 12 days didn't cause too much damage (there had to be some, right?).

As far as precipitation, at least for the past 14 days, here is a map of what fell (which included more snow)….

The ominous "hole" centered on western Kansas was expected if you read my last posting as a "temporary slowdown" was expected starting in April.

What is next?

Looking at this afternoons messy satellite image.....

Our next weather maker is the X1 up across southwest Canada.  It will move east and then dive south by Thursday.  It will usher in another strong cold front.  Depending on the exact evolution, it appears the majority of the precipitation will remain across northern Kansas but especially eastern Kansas and points south and east.  The system will be cold enough for snow again, mainly north of I-70.   That cold with that front will be brief though.  By the weekend milder air will start to return.

Going forward, it would appear the last 7-10 days of April will be much warmer.  As far as a repeat of the severe cold after that period - I'm not seeing much possibility at all.  Will there be another freeze?  During that period I don't believe so.  But - there is a small chance (less than 5-10 percent) that a light freeze or frost could occur between May 1 and May 6 for the high plains. More on that later.

Remember the dates of April 21-22 that I have mentioned since the 27th of February posting (and mentioned it again in the last update)?  Well, the long range computer models for weeks now have shown absolutely NOTHING around that date!  Am I backing off?  Nope, I'm going to stick with something (potentially substantial) happening in the general vicinity of the high plains.  Ha, we'll see.

Here is the precipitation outlook from the Weather Prediction Center valid through next Tuesday the 21st...(the precipitation you see for the central U.S. is for this coming Thursdays system)...

I'll do my best to get another post done late in the weekend or early next week.