Uncertainty is high and is the REAL cold weather too far away?

With the new weather pattern showing several different "clues", I'm getting closer to getting an understanding about the set up for this winter and what will carry into 2022.  I need another week to analyze the upper air pattern across the northern hemisphere.  There may be a big of indication that the repeating of features may be starting (or it may be another week to go).  I hesitate to make much of a prediction at this time. 

Back in late October I was seeing some forcing and subtle indications that a pattern change could occur during Thanksgiving week.  Of course that far out it timing down to a few days was impossible (or at least just throwing something against the wall to see if it would stick).  I had enough information, or at least a gut feeling, that the Thanksgiving week would be at least colder but with the possibility of an impactful storm at least within a days travel of central Kansas.  Computer forecast models this past week have been all over the place from very dry to a significant storm, but heavily leaning towards very dry. 

Looking at this mornings upper air chart....

 So far the upper air pattern has not been favorable for an significant and prolonged intrusion of cold air into the states.  There is a northern jet stream that has not "buckled" or amplified - yet.

There has been bitter cold air building across the higher latitudes of the northern hemisphere since October, just waiting for an excuse to surge south into lower latitudes.  So far, it appears parts of Europe have been hit the hardest with there ALREADY being natural gas shortages.  That is NOT a good sign as I fear the same may eventually occur across the U.S. this winter.  I have been mentioning that December could be below normal on temperatures.  Yet, long range outlooks and computer forecast models have been indicating exactly the opposite.  Another indication of this buildup of very cold air can be gathered from just this headline (about the Arctic)...

And the cold persists....look at the temperatures as of this early Friday evening (19th)...

That's a pretty big area of below zero air!  So, when will it surge south and when it does will it move into the U.S., or will it travel into Siberia and Europe?  Unfortunately, I really don't have a feeling one way or another, at least for now.  Again, I need another 10 days or so to analyze this pattern.

A couple of things that have caught my eye though....one is the North Atlantic Oscillation has it has gone negative and is expected to bottom out significantly negative.

That would promote an amplification of the upper air which "could" lead to that intrusion south.  And at the same time the Arctic Oscillation index has been trending negative which would also promote a southward movement.

Even with much colder air for a few days around Thanksgiving, the "real" push of cold into the states (including the high plains) is looking more and more likely during late November or early December.  I hope to refine that thought in the next blog posting.

As far as precipitation, at this point, it's looking fairly scarce for the high plains.  I think any storm development around Thanksgiving may favor the southern high plains and into the Ark-la-tex region but check your local weather sources as we get closer to mid-week.  Or - I just might get a chance to update by then.

And to end this posting - I'm sure this map is no surprise to anyone...

Unfortunately this stretch of dry weather for the high plains is one of the parts of the pattern that will return during the winter, spring and into summer.

"Early Winter" will be making a retreat

The advertised cold that persisted this week is starting to retreat, as it should this time of the fall.  The lowest temperatures with this event fell into the middle 20s across many areas of high plains, with just about every location reaching at least freezing.  This morning (Thursday) the coldest reading I saw was 24 at several locations, but I'd bet there were colder temperatures in preferred lower lying areas.  The advertised precipitation this week fell as mainly liquid although there were occasional bursts of sleet and wet snow.  Here is a map of precipitation, which where it did fall was actually a bit higher than expected....

Now it appears the pattern will go back into the expected drier regime for the high plains, and initially much warmer.  There will be another cold front early next week but it won't be too cold, just not as warm.  Later in the week another cold shot will arrive and it should get as at least as cold as this weeks.  At this point there is NO indication of a wet storm through at least the first part of Thanksgiving week.

This mornings upper air chart...

The stage is starting to set up for a build up of very cold air across the higher latitudes of Siberia and higher latitudes of Europe.  It will likely be a while before that is unleashed into the lower latitudes.  There has been a strong hint of this happening around Thanksgiving but at this point it could occur across the eastern U.S., or even stay across the "other side".  Any precipitation of significant should stay way out west and also east of the high plains, at least until at least Thanksgiving week.  Of course, the pattern is still in the formative stage so a "surprise" pattern shift is still possible.   

As far as a winter outlook, I'm holding off just a bit longer to access the early stages of this new pattern. There are already forecasts in place by various sources but those are based on the fact that La Nina is in place.  As I'll show in the next posting, the average weather (both temps and precip) has been extremely variable in those La Nina winters.  More next time....

The outlook from the Weather Prediction Center through next Thursday....

Here comes winter!

 In the previous posting on the 14th (read it here) I talked about the "new" weather pattern that was forming - and always does during the fall of each year (across the northern hemisphere). The first significant weather event of the new weather pattern had just concluded (primarily on Tuesday the 12th), including heavy rain, some hail but more importantly tornadoes.  These tornadoes are not the typical tornadoes that most are aware of.  They are termed QLCS (Quasi-Linear Convective System) tornadoes and essentially form on the leading edge of high winds that surge at the surface wind shift associated with a line of thunderstorms.  Meteorologists have known and somewhat have understood them for decades.  Storm spotters, however, will have a very difficult if not impossible time seeing/reporting them.  They are very quick forming and rapidly moving tornadoes.  In my forecast area of western Kansas I was able to document 10 of them that occurred that Tuesday night (12th).  Also, the majority of the time they form after dark.

Just one week later another storm system moved across the central part of the country and yet another week (last night) later another event occurred.  This sequence is one of the "keys" to this years pattern.  I have concerns from what I have already seen with respect to this coming spring weather.  Maybe not for all of the high plains, but certainly for at least the majority of Kansas and the central plains.   That discussion will be brought up again this spring.

These three systems have brought widespread rain to the lower high plains and points east.  The western high plains was mostly dry - as had been a concern going into November (I saw a possibility of an extended dry period).  But it's not surprising as many fall convective systems will fire up farther east where moisture is more readily available.  This system yesterday (and today for eastern Kansas) is one clue to winter weather this year and I would expect a winter type storm to be farther west and south.

For this past system yesterday and today, here is the rainfall that occurred (and still occurring across far eastern Kansas)...

Combing this current system with what occurred a week ago (again most of the high plains missed out)....

For the month of October (it does include a "bit" from the previous weather cycle)....

One weather element that has NOT been lacking is the stupid wind.  I know there has been some significant blowing soil across many areas of the high plains where it's been drier but with much better conditions farther east towards the 100th meridian (runs through Dodge City).  Of course, and unfortunately, these wind events are typical for fall weather. 

In that previous posting on the 14th I discussed the expected cold weather for that following weekend.  Many areas across the high plains experienced a season ending freeze western central Kansas, eastern Colorado and points north around the 16th.

But what about the remainder of the area?  Did you notice the title of this posting?  Yeah - I'm afraid so.

Looking at this mornings upper level chart with the jet stream....

The big ol' red L over Springfield Missouri this morning represents a really strong upper level storm which was responsible for the west coast getting pounded by exceptional rain totals (and snow across the high country). That is also what brought the thunderstorms last night across the eastern 2/3 of Kansas and rains today across the eastern parts of the central U.S..  And the upper high (the big blue H) across southeast Canada combined with the upper low over Springfield is a very important feature with respect to weather going forward. Looking out across the Pacific represents a very active upper level pattern, especially across the Bering Straight.  That pattern will cause the jetstream to "buckle" across western Kansas and will be tappng into really chilly (no - cold) air. Then as the pattern continues to amplify, the cold will spill into the high plains, especially next week.  Lows will most certainly fall well into the 20s across most areas.  Precipitation should form across the higher terrain and then spread a bit into the high plains.  Looking at the Weather Predication Center expected precipitation through next Thursday, what you see inside the black dashed line will be frozen, i.e., snow.  Yes - winter will make an appearance.  

If you will be having pivot sprinklers full of water prior to the arrival of the cold, just keep in mind that the air temperatures will likely fall to well below freezing next week.  I might try and update early next week if I can get a few minutes free. 

The new pattern is forming!

 Because of personal obligations I haven't had a chance to update in a couple of weeks.  In the last posting (read it by clicking here), I was discussing the upcoming stormy period that was somewhat expected for the end of September.  That would have been part of the "old" weather pattern that began forming during the fall of 2020.  The outlook for rainfall was robust with 2 separate systems expected.  Here is what round 1 produced...

And here is what round 12 produced....

The 2 event total amount was this....

In that previous posting I said "After that storm departs, it appears that it will be primarily dry for about a week.".   It all pretty much fell into place as it was dry for about 10 days.

The latest storm systems on Monday and Tuesday produced this....

Also in the previous posting I discussed several opportunities for some frost or near freezing temperatures.  I was off by a day.  Instead of the 10th (and I picked that date over a month ago), the cold settled in on the morning of the 11th with several areas of west central and northwest Kansas sinking into the lower 30s.  It wasn't season ending (as expected), but it was the first taste of "cold" morning lows. 

Now it is looking like the next "cold" and actually the coldest of the fall so far will occur Saturday morning.  Looking at the jetstream map....

First, the red L near the Canadian border is what brought the severe weather late Tuesday and Tuesday night.  The red X across Wyoming won't bring much in the way of precipitation since the atmosphere has been scoured out by the stronger system that is now way north.  But the once this Wyoming system departs, cold air will spill south into the plains.  Moring lows Saturday morning across many areas of the high plains will probably slip into the mid to upper 20s with 30s elsewhere.  So, many locations will likely see a growing season ending freeze.

Looking into the future...

As many of you are aware (at least those that have been following for a long time), the new weather pattern is currently setting up.  The two events this past week are part of this new pattern.  What happened Monday and Tuesday will be important systems to watch going forward.  The late fall and winter version may not even impact the high plains directly but will produce interesting weather close by...or yes it could impact the high plains plains.  More on that down the road.  What will be concerning is the return during the spring.  Just this simple development this week will lead to confidence that next spring the tornado count across Kansas (and possibly the high plains will be MUCH higher than the last two years).  I have a bad gut feeling that next spring we'll be dealing with an above normal tornado count.

So, again the pattern is in the process of forming.  There are several systems across the Pacific that may bring a few chances of precipitation later next week.  Details this far out are impossible and honestly trying to tie anything down that would impact the high plains really shouldn't be discussed.  

Here is the precipitation outlook from the Weather Prediction Center through next Thursday...

However, it is a real possibility that we may go into an extended dry period going into November.  I just don't have much confidence either way.   But during this next 2-4 weeks this new weather pattern will be showing more of itself. 

Finishing on schedule with timely rainfall

 In the previous posting on the 15th (read it here) I discussed the transition period from the previous pattern to the new one.  I discussed the "maybe" there would be a few opportunities for rainfall as the month ended.  The "maybe" was because of this transition but if the same pattern was still dominating then that would boost confidence.  That appears to be the case.  Looking at this mornings upper air (jetstream) chart....

The red X over the Great Basin has been in place for a couple of days and is poised to to deepen into an upper low dropping south into New Mexico.  But before that happens, a cold front will slide into the central plains and set up a zone of showers and thunderstorms.  Gulf moisture was returning robustly (late September standards) and the interaction with upper level dynamics, the front and the surging moisture should bring widespread precipitation to the plains tonight (Wednesday) and tomorrow.  A second round of more general rains will overspread the area as the aforementioned upper low lifts out into the central U.S., and the most likely time for that will be late Friday and Saturday.  After that storm departs, it appears that it will be primarily dry for about a week.

Now, don't be misled.  Not everyone will get a ton of rainfall through the weekend.  The following map provided by the Weather Prediction Center gives an idea of where the heavier rain will be centered. 

I think that almost everyone across the central and southern high plains will get at least 1/2 of an inch but there will likely will quite a few reports of 1  to 1 1/2 inches and a few locations over 3 inches. 

Also in that previous posting, I had talked about the first cold snap during the first of the week of the 20th.  That happened with low temperatures falling well into the 30s at many locations.  I never saw a freezing report but a local event of freezing occurred it would have been very brief.  Then later in the blog post I threw out the date of October 10 as a possible date of another cold snap but probably not a "killing" freeze.   There is some support that date may be good.

Later into October - I'm not seeing much indication of a BIG cold blast.   BUT - the new pattern is in the process of setting up and rapid changes can take place.  More later....

I'll end this one with this graphic....

That zone between colder than normal and warmer than normal Pacific Ocean waters "MAY" be a big contributor in at least the fall and early winter cold shots.  I'll try and address that in the next posting or two.

A transition time for the atmosphere!

For those that have heard my presentations or have read this blog, you know that an entirely new weather pattern starts to form in the fall - centered on about October 1.  What has transpired this first half of September is more than likely entirely the previous pattern but we may be seeing bits and pieces of a new pattern this second half of the month.  In the previous post I did on the 26th of August (click here) I thought there would an increased probability of at least a  couple of "wet" events.  for the second half of September.  More than likely that first chance was the past 36-48 hours and here is what occurred across the area....

But since it appears that "a tiny bit" of the new pattern is showing up, the likelihood of another opportunity for rainfall for the high plains is somewhat in question.  It's not a zero chance, but there is some strong hints that there may not be much for the next 10 days which takes us into late September.  I'm not totally confident of another chance or two, but it would be surprising if we didn't have another system, at least before September is out. 

In addition, a "real" cold front may make an appearance by the first of next week.  The driving force of that "cold" weather is likely a western Pacific tropical storm/typhoon which often causes amplification in the jetstream.   Now I'm not talking about a freeze, but for a couple of days high temperatures may be in the 60s or 70s and lows a couple of mornings next week may briefly fall into the upper 30s (for a minimum) across the high plains.  That period of cooler weather should not last more than a couple of days.

Then as we get towards the end of the month, maybe, just maybe there could be a couple of opportunities for precipitation.  I'll evaluate that during this next week.

As far as the first freeze of the fall?  My gut feeling is it will occur earlier than normal by perhaps a week or so.  If I was to give a date - the guess would be centered on October 10 give a day or two.  As far as a killing freeze?  Probably not yet.  

I'll finish this short post with the outlook for rainfall from the Weather Prediction Center or the next 7 days (into the 23rd), again not much.

Let's hope for that last week of September.

Will this be the last "blast of heat"?

 In the previous posting (read it here) I discussed some major changes across the higher latitudes of North America.  The change had, at least temporarily, shut off the North American Monsoon.  But as the atmosphere adjusted to those changes, the pattern of jetstream winds that developed last fall (2020) "bounced back" into place and a similar pattern returned.  The heat across the high plains has been a bit more extreme than it had been earlier in the summer, but was actually expected for this exact period.  However, I was not expecting it to persist more than 5 to 7 days and we're approaching that length of time.  But at the same time I'm not too surprised as summer comes to a close and the atmospheric winds spin down before increasing again here in the next two to three weeks.  And those that have been following my blog know that the "new" pattern will be developing within the next 5 weeks.  I do have some evidence that it may actually start to develop in late September.

Here is a look at the jetstream (the solid arrows) from this morning....

One item to note is that the North American Monsoon has returned for one last gasp (the dashed green arrow), and has helped to bring more precipitation to areas of the high plains (mainly Colorado and Nebraska).   Unfortunately many areas of Kansas and west Texas have missed out during this past few weeks (again the atmosphere is spinning down for now and this has impacted the weather).  The map of rainfall for August through yesterday, the 25th, shows those that got it and those that did not.

But in reality it could be much worse if it weren't for good rains earlier in the growing season.  Here is the latest drought map...

Some of you may have caught wind of a tropical system bringing rain to the high plains the first few days of September.  Unfortunately that came from my agency that I work for and what was depicted is just not realistic - there just isn't predictability 10 days out for details such as were depicted.  The chance that a tropical system will develop in the Gulf of Mexico is near 100 percent.   It will even probably become a strong hurricane.  But as is typical, the exact track is very much unknown as of this Friday afternoon.  The earlier map from my agency had it moving towards western Kansas.  I've been in the weather business since 1983 and the ONLY tropical system moving out of the Gulf of Mexico that impacted western Kansas directly during that time period was Alicia in 1983!  Even going back 150 years - that is the ONLY one!  Remnants of dying systems can bring precipitation but it is FAR more likely from remnants of Pacific systems. 

Ok - does that mean it will be dry first week of September?  Not necessarily because there could still be a disturbance move along the westerlies (the jet stream) coming in from the Rockies.  There is a chance based on the pattern than got established.  But at this point it doesn't look like there is widespread precipitation on the way. In fact, here is the outlook of rainfall through September 3 (from the Weather Prediction Center)...

Later in September?  Yes I think so and in fact looking at the repeating pattern that started last fall, and even given the end of the patterns cycle is near, the last half of the month should have an increased probability of seeing at least a few good chances.  One of the forecast models that has consistently been predicting a wetter than normal September and has this....

But - the bad news is the skill of this model for this time of year and pattern is extremely low (hence what you see in the bottom two panels of gray).  But I would lean towards the probability of at least a couple of "wet" events - again based on the pattern and not what is depicted by the model.

More later on a possible early freeze.