Friday, January 22, 2021

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.

Friday, January 8, 2021

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.