Rounding Out March

First off, a big thank you to those that have submitted the very quick survey that will help me decide the direction this blog will go and what I potentially will be doing in the not too distant future. If you haven't had a chance to complete the survey, the link is: https://www.surveymonkey.com/r/7ZSGTTG.  It is very brief and will take you less than a minute.

I think just about everyone will be pleased with how the March weather has turned out across the high plains.  Beneficial moisture (more or less),and relatively mild temperatures can summarize the month.  Yes, there was a major blizzard/snow storm across the western part of the high plains (especially the Palmer Divide and Front Range).  But a major blizzard spared the remainder of the high plains.  But, it was close!  The widespread and major late winter storm on the 13th and 14th was really close to slamming the entire area with a mind boggling blizzard.   East of the extremely heavy snow there was instead widespread rain, some very excessive.  I was travelling back from Omaha on the 14th and experienced an east wind of 50 to 60 MPH with heavy rain at 38 degrees!

For March, the Dodge City airport was sitting at the 5th wettest March on record and those records date back to 1875!  And for Ford County, where the airport resides, the monthly total is actually far less than some other reports!  Of course not everyone got excessive rainfall but just about all locations got at least enough to improve drought or near drought conditions.  

Here is the map of estimated precipitation since March 1st (through the 25th)...

This amount of precipitation has helped mitigate drought conditions.  As of the 23rd, this was the latest map....

With the March precipitation, the improvement across many areas was substantial!

For the short term the final in a series of weather systems was moving out into the plains.  As of early this Friday morning the center of the system was located across Arizona.  It was weakening as it was moving out.  A few sprinkles were noted across the high plains but because the boundary layer of the atmosphere had been scoured of moisture, the system just isn't strong enough to produce significant rain.  Farther east, later into Friday evening, there was enough moisture for scattered thunderstorms.

In several of the previous posts I had mentioned March 25-31 as potentially being "cold" or at least below normal.  The pattern is set but because of the northern branch of the westerlies (jet stream) being strongest across Canada, the really cold air has been held up north.  Good thing!  With the colder air being held north and with the configuration of the jetstream, the Arctic Oscillation has been really positive in magnitude, polar opposite to what it was back in February.

The index was headed south (less positive and inching towards a negative value). IF (a big if) the AO index does go negative, that could set us up for that April 25-May 2 possible cold that I had mentioned.  BTW, if you missed it I discussed dates with the highest potential for having significant weather.  If you didn't see it, click here.

After doing some more analysis, I have come up with 2 more periods of potentially significant weather.  One period is April 4-8 where I think there will be an increased opportunity for thunderstorms. Hopefully far enough west to benefit the area with drought conditions.  The second period is May 6-13.  This could be  a pretty active severe weather set up.  I still think that April 25-May 2 could be really interesting and potentially very impactful at least for parts of the area.  The potential for cold still is there but it could also lead to a battleground from west to east of cold to warm.  More on this later.

Finally, this next 7 days should see ups and downs on temperatures.  Warmer/milder through the weekend but then much colder Tuesday through Thursday with probably overnight lows below freezing.

Thanks again to those submitting the survey.  

Wild March Weather - 300th post!

The weather has certainly been interesting this past week!  From severe thunderstorms to a major spring snowfall.  In the previous post I gave some periods that I believe to have pin-pointed.  If you didn't read that post, click here.

In the previous posting, I provided a link to a very short and quick survey that will help me determine the future of this blog and posts.  If you have not filled out that survey (again it's very brief), please help me out and do so.  That survey link is: here 

To date I have posted 299 times, this one is my 300th!  The first one I did was on April 15, 2014!  Wow I can't believe it was that long ago!  For those of you not too familiar with this blog, I have done it on my own time unrelated with my employment with the National Weather Service.  If you want to read that very first blog post, click here.  I need to determine if I will continue.

In the previous posting, I discussed the active weather expected for the period of March 10-17, but especially March 15.  Well it certainly has been active with the highlight being the 13th/14th.   It looks like the storm coming in tonight and moving out tomorrow (16th-17th) will be the end of that active period.  But, there is more to come! 

BTW, here is the estimated precipitation that has fallen this past 7 days, ending this morning March 16.

Here was the upper air chart this morning...

The Storm (the red L across Arizona) for tonight and tomorrow will be very compact making details in the forecast (type of precipitation and specific amounts) extremely challenging for forecasters.   The exact track and mesoscale processes will determine the final outcome.  Here is the guestimate from the Weather Prediction Center for the next 7 days (with the majority of this falling with this first system)...

So, if you didn't go back to the post on the 5th, here is the outline I left you with....

These following periods are not the ONLY possible weather....they just have my attention.

1) March 10-17, but especially around March 15.  This should be the next active period but probably only 1 storm will impact the high plains and that would be around the 15th.  Before then it could be the eastern plains.  I wouldn't be surprised if there was a blizzard, especially for higher elevations of the high plains.

Instead of 1 storm for the high plains - make that 2 although much of the high plains north of Kansas will miss out on this one.

2) March 25-31 is a period of potentially much below normal temperatures.  That could be problematic as with this recent rain and the mild temperatures coming up, there may be some early breaking of dormancy of some vegetation.  Also, the b word comes to mind.  The last 10 days of March are actually the most active for blizzards, based on history.

I think there will be a few more opportunities for storms as March is closing out.  Any system that would bring much below normal temperatures is not showing up at this time.  But, I still think there is that chance.

3) April 17-20 could be interesting.  If the warm sector is far enough north/west then perhaps a severe weather outbreak?  Hopefully no blizzard but I wouldn't be surprised for areas of the high plains.

This still looks to be on track.

4) April 25-May 2 could potentially see much below normal temperatures.  If there is going to be a late frost or freeze, that would be the time period.

No change in the thought process for this period.

I will wait a bit more before venturing out on a summer outlook. 

Again if you didn't have a chance to fill out that brief survey, I would appreciate it greatly if you could help me out. 

March Update

This is going to be a long post since I haven't updated in a month.  For those longtime readers, you know that I've discussed the difficulty in finding time to update this blog.  The posts I make about the current weather trends and outlook are made on my own time and are my own thoughts and are not part of my employment at the National Weather Service.  I regret that I'm not able to update more often.  When I retire from the agency (not that far away) I would be able to update quite often - but of course it wouldn't be free. :-)

To give me an idea if this blog is even worth my time, I would like for you to take a very brief survey.  It will take you less than a minute and you will remain anonymous.   I would appreciate it.  If you would, please Click here for that quick data gathering survey.  Thank you.

So, there is a lot to discuss since I haven't updated since the post on February 5.

First, just as a refresher and perhaps the following will be new to some of you...

When fall arrives, the jet stream across the northern hemisphere starts to intensify (speeds increase) and areas of maximum and minimum speeds fluctuate as these areas move around.  A pattern of where the jet stream winds intensify/amplify meridionally or latitudinally becomes established.  This pattern has been known to repeat around the hemisphere on a periodicity that varies from one year to the next. I have found the repeating nature to be from 45 to 60 days, but it has been outside of that range.   What causes the jetstream to behave in the way it does (differently) from one year to the next are influences from oceans and land masses - and probably the sun.   Some influences are more dominant than others but those tend to change from year to year.  Even on an intra-seasonal time scale the influences can change.

Some of the changes that influence the jetstream can from the tropical oceans (Atlantic, Pacific, Indian Ocean), northern latitudes of oceans, landmass/ocean interactions, Arctic oscillations of surface pressure,  stratospheric warming, blocking of the jetstream across the higher latitudes, etc. 

You've heard of El Nino and La Nina (warming or cooling of the equatorial Pacific oceans).  Many people will give a seasonal outlook solely on these events as if THEY are the ONLY factors that influence the weather pattern.  There is plenty of data available to quantify weather based on these events and that data shows a different outcome from event to event.   Based on the current La Nina, here is an outlook from The Weather Channel that was valid for February:

Did they do pretty good?

What about from the Climate Prediction Center (NWS)?

Pretty good?  I'd say a lot better.  Now, granted, this was an updated forecast made Jan 31.  Their original outlook looked similar to The Weather Channel.  What I saw on Feb 5th was that the build-up of brutally cold air (causing the Arctic Oscillation to go strongly negative) was finally going to make a visit on "our" side of the hemisphere.  The two other negative events (not as negative) were unleashed upon Siberia and Europe.  Plus, there was strong evidence of a significant Madden Julian Oscillation (MJO) and that MJO became VERY significant and I think had the greatest impact on our February weather. 

The MJO was well established and influential. 

But now look what has happened to the Arctic Oscillation! 

That is a major shift to the positive side!  Even though we are currently seeing a dip, the AO is forecast to go strongly positive and potentially with a magnitude that I haven't witnessed.  Now my question is just what influence will this have on the pattern for the next few weeks.   Is the AO the main controlling factor on the jetstream?  Or could be be forcing from perhaps the western Pacific (not La Nina).  If the cooling on the equatorial Pacific is the main influence, then there probably wouldn't have been this storm we just had.   

Now there is evidence of a resurgence of another MJO, just not as strong as the February event.  Regardless, I think this developing MJO in the presence of the pattern that developed during the fall has given me confidence of several periods of active weather or changes.  I actually had these dates in mind back on the 20th of February (the last time I intended to update this blog).  I haven't changed my  mind since then.

These following periods are not the ONLY possible weather....they just have my attention.

1) March 10-17, but especially around March 15.  This should be the next active period but probably only 1 storm will impact the high plains and that would be around the 15th.  Before then it could be the eastern plains.  I wouldn't be surprised if there was a blizzard, especially for higher elevations of the high plains.

2) March 25-31 is a period of potentially much below normal temperatures.  That could be problematic as with this recent rain and the mild temperatures coming up, there may be some early breaking of dormancy of some vegetation.  Also, the b word comes to mind.  The last 10 days of March are actually the most active for blizzards, based on history.

3) April 17-20 could be interesting.  If the warm sector is far enough north/west then perhaps a severe weather outbreak?  Hopefully no blizzard but I wouldn't be surprised for areas of the high plains.

4) April 25-May 2 could potentially see much below normal temperatures.  If there is going to be a late frost or freeze, that would be the time period. 

I'm not ready to venture into an outlook for the summer.  For a while this winter I was seeing resemblance and similarities to 2011.  Ugh.  I'm not sold on that yet so don't panic.

Again, if you wouldn't mind doing the quick survey...it would help me to determine the direction I go from here.

It is Winter After All - update Feb 5, 2021

For the most part it's been an abnormally mild winter - so far.   With the weather pattern that was established during the fall, the initial thought was that any brutally cold periods could be somewhat infrequent.  Without knowing what the main influence on the weather pattern was, confidence on temperature and precipitation patterns was not very high.  

First - back to the post I did on the 22nd.  I've been discussing a mid-month chance of the next significant precipitation event (for the High Plains), specifically a day or two around the 15th. What is currently going on across the northern hemisphere (and on our side - as opposed to the Asian continent) may mitigate what happens around the 15th.  

First things first.  Those that have read this blog for many years have read about the Arctic Oscillation (AO) and North Atlantic Oscillation being a contributor to our weather, especially during the colder months of the year.  A very high percentage of the time when the index of the AO becomes negative for a period of time, high latitude (particularly Arctic) airmasses are dislodged into the U.S.. Look at the AO for the past 3 months and what is expected for much of February (the gray shade)....

The sigma numbers on the left scale indicate the Standard Deviation from normal (SDN).  A 2 to 3 SDN is extremely significant and for the index to be that low/strong for that long is mind blowing.  Sometimes this means the cold is the other side of the hemisphere but other times it is on our side. But, the cold usually oscillates from "that side" to "our side".  That hasn't happened until currently.  We're about to pay for that relatively mild winter!

Here was this mornings upper air chart....

The big red L up across the Canada is the "polar vortex" (strong upper level low) that has been displaced south and west from a typical winter location.  This is in a perfect position to allow surface high pressure to get very high and move the Arctic air south.  BTW, this setup is a direct result of something called Sudden Stratospheric Warming (Google that if you want to know more) that occurred a couple of weeks ago.  The red X near the Canada/Washington border is a fast moving upper level disturbance that will help spread snow across Nebraska and the northeast half of Kansas late tonight and Friday.  Behind this system will be the first surge of Arctic air into the central U.S..  

But there are other disturbances that will be sliding southeast across the central U.S. into the first of the week.  The Arctic air will mitigate very briefly but then come in with a vengeance Sunday night and stick around through next weekend (the 13-14), at least.  I would not be surprised to see single digit highs later next week with a possibility of low temperatures falling well below zero (-10 to -15 depending on clouds clearing out and any snow cover).  This is for the high plains.  Farther northeast temperatures will be even colder!  

As far as precipitation next week, there should be several rounds of snow that eventually will add up to several inches.  But, it will be a very dry snow with very little moisture with it.  As far as a significant storm around the 15th as indicated in the past few blog posts - there could still very well be one but with the airmass being so cold and eventually very deep (the cold air), an organized storm does not seem likely.  It's still possible, just not likely.  But, there should still be a period or two of snow.  By the 15th and after several rounds of snow, there could be snow depths of at least six inches across some areas of the high plains.  Here is the precipitation outlook through next Friday (from the Weather Prediction Center)...

Since any snow would be dry in nature, it won't help much with the drought.  Here is the latest map valid for February 2.

I'll try and update next week and discuss the trend through the rest of February and into March. 

Update - Jan 22, 2021

 In the previous post on the 8th (read it here) I mentioned the last 7-10 days of January and into the first few days of February should be much colder with a couple of chances of precipitation.  This morning there were single digit temperature readings a few locations across the high plains with mainly teens observed.  This was after a couple of "mild" January days. Single digit temperatures were widespread across the Midwest.  This signals the start of the change.  It is puzzling why the bitter cold air hasn't made much push into the U.S. since the Arctic Oscillation has been extremely negative for a long period of time.  The cold air is there, it's just on the other side of the hemisphere.  I don't know about you, but I'm perfectly fine with that!  So far for December into the 22nd day of January it's been around the 10th warmest start to winter on record! 

On average, the balance of January into early February will be characterized by normal to below normal temperatures - but still with a few days on the mild side.  As far as precipitation (and as advertised in the previous post on the 9th), there will be several opportunities for rain and snow.

Looking at this mornings upper air map...

The atmosphere is set up to deliver several of those opportunities for moisture.  But, as usual, the million dollar question is where and how much!  This morning there was an upper level low across northern California and it was moving east and southeast.  But it will quickly be kicked out and will quickly die out as it swings into the Rockies.  The culprit is a strong disturbance associated with a jetstreak (maxima in the jet stream winds) that will be diving south.  This disturbance will intensify and take a track denoted by the red arrow on the map.  This will be the precipitation maker for late Sunday and Monday.  However, that system has a LONG way to track so it's really up in the air as to the exact track and how the corresponding surface features develop.  Also the area and intensity of the precipitation will be highly influenced by potential thunderstorms across Oklahoma and Texas. The precipitation will be mostly snow across Kansas, Nebraska and Iowa.  You'll want to check with local forecasts from your favorite source for detailed information.  As of this Friday afternoon the bullseye of heaviest snow seems to be from Salina to south central Iowa.  Here is a best guess for 4 inches and higher...

Back to the upper air map.  There was another strong storm out in the Pacific and it appears that it will take the green track.  But there are indications it will undergo weakening as it moves into the plains.  It's impossible to predict eventual surface features and precipitation areas, but it should impact the high plains and points east sometime around mid-week.   Here is the outlook from the Weather Prediction Center through the end of next week (taking into account the two storms mentioned above)...

Beyond the two upcoming opportunities, there should be at least one more system that may impact the high plains around the first couple of days of February.  Confidence is low.

Then, I would wager a quiet period until mid-February.  Around the 15th of February, it has my attention on being the next significant chance for a storm across the high plains.  But, then maybe nothing again until late in the month.  If we miss out on these opportunities this next 40 days, the drought area will start to expand again, even though it's still winter.

I'll end this posting with a discussion about the Madden Julian Oscillation (MJO).  There is a developing MJO that is forecast to become pretty strong.  There is pretty good consistency with computer models on it's eventual evolution.  In previous discussions I talked about the "phase space" for the MJO.  If indeed the MJO becomes as strong as indicated, the impacts typically are noted in the map below going through much of February...

This would favor the areas that have been so wet this past 2 months, especially the mid-Mississippi Valley.  For the high plains there is "some" signal of above normal precipitation.  But I feel there are other contributors to weather pattern so I don't want to get too optimistic for February.  However, that mid-month opportunity could make the entire month, if it occurs.  

I'll try and update again around the 29th.

It's all on track - Updated 01/08/21

 In the previous post (click here) I discussed the storm(s) that were going to impact areas mainly east of the of the high plains.  That did happen, with the exception the the southern high plains got a decent snow from the parting storm.  Here is a look at the precipitation map for the 14 day period ending this morning...

That is an impressive amount moisture for areas of Oklahoma, eastern Kansas and into Texas, especially for the winter time.  With this additional rain (and snow), the drought map shows how much improvement has occurred in that region, and keep in mind this does NOT include what fell earlier this week.

In that previous post I said "That could very well impact the central U.S. once again around January 9, give or take a day.  That should be the next significant chance of precipitation after this Thursday/Friday (again east of the high plains)."  

Once again it looks like a system will indeed be present and is right on schedule!  But this time the main precipitation event (and it appears to be almost all snow) will be farther west and south impacting mainly the southern high plains again and then eventually deep into Texas.  Here is the upper air map...

As of this morning the system was entering the west coast and racing east but had taken a turn southeast as it began amplifying.  Here is the outlook for precipitation through the end of the next week with the the precipitation depicted for the plains occurring late tomorrow (Saturday) into Sunday.

Back to the upper map. There was a very energetic upper level low across the eastern Pacific (depicted by the red L), but it appears that it will rapidly weaken and move north.  This tells me there is a change going on across the Pacific Ocean Basin.  What does that mean for the high plains?  Nothing initially as it fits the weather pattern.  It's too bad as that system, if it were to continue moving east, could have been a big weather maker for the central part of the U.S., but not this time.

So, after this weekend, much of this following week there should be a pretty good warm-up, especially for the northern high plains.  I don't see much chance for any precipitation for the work week.  The next significant change, will probably be around the 18th (give or take a day) with a significant cool down expected and with another chance for precipitation across the plains.  In general, the weather the last 7-10 days of January should be much colder with a couple of chances for precipitation and this should carry into the first few days of February.  Details to follow.

The Bad, The Good, and The Bad - and Maybe Ugly (12/29/20)

If you didn't get a chance to read the previous post I did on the 24th, click here.  

The advertised precipitation event I discussed back on the 17th, was just a tad slower in evolving.  Some of the precipitation began the night of the 27th with a band of snow that moved across west central Kansas into northeast Colorado, northern Kansas and into Nebraska.  The second wave of precipitation began last night and into this morning (29th).  Here is a precipitation map from late on the 27th until 7 AM this morning....

The rain, freezing rain and sleet that started overnight and continued through much of the day as it shifted east was not necessarily a single storm.  Rather it was a maxima in the upper level wind field that promoted what is called a "warm conveyer belt" and produced lift across the relatively shallow cold airmass aided by a surface warm front that was moving up into southern Oklahoma.   Here is the 24 hour precipitation map for Kansas, ending at 4 PM and provided by the Kansas State Mesonet...

So, the bad.  Well, this "significant" precipitation event was farther east than what would have been preferred for the drought area of the high plains.  That has been a common theme for much of the fall and now early winter.  Comparing the map above to what occurred around in early November...this pattern of precipitation was farther east by about 50 miles (in regards to the heavier precipitation).  These sharp gradients of very little to a whole lot have repeatedly occurred this past 70-80 days.

The Good?  It was another significant precipitation generating weather system for the central U.S. that was "right on track" as far as long range predictability.  This boosts confidence going forward for other potential impacting events.

The bad or maybe ugly?  The same area that has missed the big events may miss many of storms going into spring.  The caveat is that some of the forcing areas around the northern hemisphere generating these storms have changed slightly.  My hope would be the pattern could shift west a little, with time.  

Looking at this mornings upper level chart....

                                                          500 MB - 12/29/20 at 12 Z

The main upper level storm was located across western Arizona.  Typically this would be a nearly perfect location to impact the high plains.  However, because of upper level ridging across the north Pacific and something referred to as Rosby Wave Propagation across the entire Pacific basin, this upper level low is predicted to take a track closely resembling the red arrow.  That is, the upper level low will intensify/amplify as it dives across northern Mexico before lifting rapidly northeast and then north across the mid-Mississippi Valley.  That will result in a tremendous amount (remarkably high) of precipitation (mainly rain)!  However, that track also keeps the precipitation out of the high plains.  IF, the storm were to take a track annotated by the green arrow, then we'd be in good gravy.  That won't happen (99% chance it won't).  Here is the outlook from the Weather Prediction Center (and keep in mind this in addition to what fell today)...

The western edge may be a bit too far west. 

You may also notice lots of precipitation across the west coast.  Great for them!  It also is an indication of an active upper level pattern across the Pacific.   I'm seeing indications of a developing extended east Asian jet stream (very energetic winds coming off the mainland due to very high pressures across Siberia).  That could very well impact the central U.S. once again around January 9, give or take a day.  That should be the next significant chance of precipitation after this Thursday/Friday (again east of the high plains).