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.

Changes in the weather?

In the previous post on the 30th (read it here), I discussed the overall typical summer time pattern.  The North American Monsoon had been ongoing, and strongly, for 2 to 3 weeks and that has continued until just a few days ago.  More on that....but first...

In that previous post I mentioned that because of the weak summertime flow, that only a "only subtle changes in the flow aloft and at the surface can bring a change."  Just enough of a shift allowed for at least some areas of plains and central U.S. to receive a pretty good amount of rainfall (this past weekend) and then a few spots benefited last evening (the 4th).  Here is a map of the rainfall this past 7 days ending this Thursday morning...

The latest drought monitor map shows the improvement across Colorado...

Now - additional changes are showing up across the northern hemisphere.  Look at the jetstream map from this morning....

Those Upper lows (the red L's) across the higher latitudes are a big change and they are pretty strong for this time of year!  However, the only real impact for the high plains is shifting the westerlies (the wind aloft) east into the U.S. with the first indication of the upper system entering the west coast.  This has shut off the North American Monsoon and is poised to warm up the central plains to around 100 or a little more.  Unfortunately it will also strengthen the Elevated Mixed Layer (warming aloft) and will decrease the threat of thunderstorms.  There will probably still be some (primarily Saturday) but it appears that areas of storms would favor locations mainly east of the high plains.

The hot temperatures may not last "that" long depending on the evolution of the jet stream.  I'll have to reevaluate what this shift will do for the remainder of August and I'll take a look later next week so look for an update.  For now, here is the outlook for rainfall through late next week (notice the change across the Rockies).

If you're down at the PRCA rodeo in Dodge this week, I'll be around most days - at the Ford county Emergency Management booth, wondering around, or at the ticket gate.  Stop by and say howdy.

The Dog Days of Summer

 A somewhat typical summer regime is in place across North America and has been for the past few weeks or so - AFTER the swarm of Iowa tornadoes!   The jet stream has retreated well to the north, which again is typical.  Here is the jetstream map from this morning....

The Big blue H (upper high) is parked right over the central part of the country.  What had been expected by some "weather people" to produce extreme heat has instead just limited the amount of storms.  In the previous postings I did back in June I said "The rainfall across Oklahoma and Texas could very well have a feedback on July weather."   I believe that is what has happened for the central U.S. as moisture near the surface has helped keep temperatures at bay. 

In the post I did early this month on the 15th (read it here), I said "I'm still not seeing much evidence of an extended "very hot" period for the rest of July other than a few days of near 100.  I still see a chance that the average monthly temperature for July will be closer to normal, if not below."    Indeed that is pretty much what this month did.   There were a few days of 100 or close but overall no extended periods of very hot weather.  As for precipitation, some areas will end up drier than normal but other locations will have had above normal July rainfall.  Here is a map of what was observed this past 14 days....

I'll post the July rainfall in the next posting....

Again, some areas benefited from several systems.  It's unfortunate that not all locations received these rains but that is the nature of warm season precipitation.  

Going forward into August....

The biggest player may be that upper level high and where it meanders to.   Back to the previous post on the 15th...."The pattern will continue to wind down in August so it's really uncertain what to expect other than perhaps a short period or two of 100-105 degree days (but maybe not many).  Some of the very long range computer models do hint at normal to above normal precipitation for many areas of the high plains.  I'm definitely not ready to jump on that notion, at least not yet".

Transitioning out of mid-summer and heading towards fall is a very difficult period to make an outlook.  Since the jetstream is so far north, only subtle differences and shifts in the flow aloft and surface pressure can bring changes.   The key for the next week may have been a typhoon across the western Pacific that came close to impacting much of Japan.  There is quite often a downstream energy propagation that promotes cooling across the U.S. and that is what is happening currently.  By the end of the weekend and into much of next week, temperatures will be much cooler (and actually below normal).  As far as precipitation, the majority will shift west across Colorado, New Mexico and west Texas.  There will still be at least a small opportunity for the high plains of Kansas and Nebraska but it may stay west.  Here is the outlook for rainfall through the end of next week - provided by the Weather Prediction Center....

Again, only subtle changes in the flow aloft and at the surface can bring a change.  I wish the rainfall would be farther east, but at this point it does not appear so, at least yet.

As far as for the remainder of August, I still see a couple of periods where high temperatures will top out at over 100 but any period of that type of heat will be relatively short lived.  Some of the computer models that go out well into the extended has still hinted at above normal rainfall.  I would wager to go drier - not completely dry though.  Perhaps similar to July where some areas get some decent moisture but yet some that miss out.

BTW, unrelated to weather, a few of you have asked about my giant pumpkin growing.  As of this morning I have one that has topped out well over 600 pounds (estimated by using a measurement method).  For those interested, I do a blog for that at: https://jeffsgiantpumpkins.blogspot.com/

Trudging along and it's not too bad!

In the previous post I did on June 28th (read it here) I discussed the screwed up weather pattern.  Now it seems that the atmosphere has settled down into a more typical regime.  Or is it?  Did you happen to catch the news of the tornadoes in Iowa yesterday (14th)?  Tornadoes in July really is not that unusual, especially across higher latitudes of the country.  But what made those stand out to me was the intensity, size and how they were able to form in a not-so-favorable environment, especially the size and strength.  Then we slide down into high plains.  An upper level disturbance moving slowly east out of the Colorado Rockies in moderate flow aloft (July standards), was capable of producing a pretty good swath of precipitation.  In the upper air map below, that disturbance (as of this morning) was across southwest Kansas (the red X).

Unfortunately, not everyone got good rain.  But there were some areas that got really decent rains during a period of extended dryness.  In fact that extended dryness this past 2-3 weeks has shown up on the drought monitor map.

A good chunk of the abnormally dry area analyzed on the map for Kansas got those overnight rains - except for areas near the Oklahoma border.

As far as rainfall with this overnight event and others in the past 14 days, here is what has fallen in that 14 day period.

The North American Monsoon has been suppressed into Mexico, Arizona and New Mexico but it will make a return.  With that return, there should be other disturbances that should bring at least scattered thunderstorm rainfall to many areas of the high plains for the remainder of July.  Here is the outlook from the Weather Prediction Center for rainfall through next Thursday the 22nd.

I'm still not seeing much evidence of an extended "very hot" period for the rest of July other than a few days of near 100.  I still see a chance that the average monthly temperature for July will be closer to normal, if not below.  The pattern will continue to wind down in August so it's really uncertain what to expect other than perhaps a short period or two of 100-105 degree days (but maybe not many).  Some of the very long range computer models do hint at normal to above normal precipitation for many areas of the high plains.  I'm definitely not ready to jump on that notion, at least not yet.  I'll try do a bit more analyzing on that outlook and discuss that in the next posting.