Friday, February 27, 2015

Update - February 27, 2015

This is my busiest time of the year doing presentations on severe weather so the frequency of updates will be less.

In the previous post last Friday (click here) I discussed the possibility of heavy snows across Colorado and extending out into the plains.  The following map is the approximate amounts reported across western Kansas.  Keep in mind there was quite a bit of wind so there were bare spots.  Those crop fields with residue or CRP fields caught a lot of it...(click for a larger version).

The immediate attention turns to several upper level storms associated with the jet stream.  The first near the Four Corners will spread snow across much of the area into Saturday.  The second was diving into California.  The possible snow amounts are still uncertain, even this close to the event, because of the sparseness of the upper air sampling.  We really don't have handle on the moisture and temperature profile where the snow will be forming at, until the event starts to unfold.  Computer guidance is all over the place so is of little help.  But, I will throw out an educated guess, and see what happens.  First the satellite image...

and now, the guess...

There could also be sleet or freezing rain across parts of south central and southeast Kansas and northern Oklahoma.  Again, it all depends on the temperature profile as the events unfold.

Beyond this weekend, next week could become pretty active with a strong Arctic cold front headed this way.  The warm air surge may make it well into Kansas which will probably bring low clouds and drizzle (or freezing drizzle until the temperatures warm to above freezing).  Severe thunderstorms might even be a possibility across far southeast Kansas!

At this point any heavy accumulations of snow from that storm will likely be across Colorado.

Good news!  Much warmer weather is expected by next weekend (March 7th).  More on that later when I get a chance to post to this blog (hopefully by mid-week).

Friday, February 20, 2015

Update - February 20, 2015 - Back to winter

In the post I did on Tuesday (click here to read that one), I discussed the record setting cold across the eastern part of the country and the position of the upper level ridge.  First, even this morning, low temperatures were around ALL TIME records across parts of the east.  It was at least -32 this morning in Kentucky.  Amazing!  And better them than us, right?

Second the upper ridge position (click here for that map) was far enough east that it prevented the brutal Arctic air from spreading into the plains.  But now, changes are taking place.  Look at the satellite image below and notice how the upper ridge is shifting west.  (click for a larger image).

On Tuesdays satellite image I pointed out the two systems off the Pacific northwest coast.  They have now rounded the top of this ridge and are heading southeast.  The first one will bring a little rain, freezing rain or sleet to parts of Kansas tonight and then another major snow for Boston later in the weekend.  The other one across southwest Canada will slide south and cause the jet stream above us to get very energetic.  The temperature gradient above the surface will become very compact and with lifting and convergence should become the focus for significant snow Saturday night into early Monday.

The first guess for snowfall through Monday follows.  Don't take the numbers too literally as there will be mesoscale (small) scale processes that will shift the axis of heavier snow during the period.
This outlook will no doubt change so the best advice is to follow your local National Weather Service office for the latest outlook.  Go to and click on your area.

In addition to the snowfall, temperatures will be plummeting.  There may be a small break next week (but don't pay attention too much to those NWS temperature forecasts as they likely will be too warm), but overall it is going to stay cold for the balance of the month. 

Also, there will likely be another storm or two during the 7 to 10 day period following this current storm expected this weekend.   There very well could be areas of far west central Kansas and eastern Colorado that may see upwards to 2 feet of snow between this weekend and March 1st.

Tuesday, February 17, 2015

Update - February 17, 2015 - Unsettled Weather

In the post I did on Friday, click here, I discussed that due to lack of snow cover across much of the northern plains that the Arctic airmass might be modified a bit.  The cold air that arrived Saturday, spreading northeast to southwest, was certainly modified.  While record setting cold has gripped the upper midwest and northeast, here in the high plains it has turned colder but definitely not brutal.

This mornings snow and ice analysis showed more of the country covered - compared to last Friday. 
You can see last Friday's map by clicking here.

One reason the center of the cold, this time, has not impacted the high plains is due in part because of the orientation and location of the upper ridge.  I've marked that location on the satellite image below.  It is farther east this time (as opposed to the November and early January versions).

Another reason, in part, that the Arctic air has not spread back against the Rocky Mountain front range is that the Arctic Oscillation has been strongly positive.  That was unforeseen this go round.

But will both the ridge and AO stay in this configuration?  Not entirely.

The two X's on the satellite image off the Pacific Northwest coast represent two systems in the upper atmosphere that will be rounding the top of the ridge and then will most likely amplify as they turn south.  This should initially bring a brief "warm up" to the area late in the week.  Depending on the amount of amplification and the eventual track, there should be active weather developing in the Rockies by Saturday, and possibly spreading into the plains.  In addition, the amplification will allow the Arctic airmass to move south but also west.  I'll update later in the week, but be prepared for unsettled and increasingly colder weather by the weekend, especially for Colorado.

On the Arctic Oscillation  - if the index dives into the negative during the next 7 to 10 days, then the last week of February would be brutally cold across the area.  I'm not confiident of the severity, but it does look like the balance of the month will be mostly below normal, as far as temperatures.

One of the long range computer forecasting models does show a trend to stay colder than normal right through much of March.  I do think there will be a warmup, but March typically can become pretty variable in terms of weather systems.
I would agree that the month on average may end up below normal, but I bet there will be some pretty mild periods too, most likely during the mid part of the month.   This will have to be watched in case it gets "out of control" and gets the winter wheat to break out of dormancy.  Look out for the threat of a March blizzard the last 10 days of the month followed by a significant cold period the first week of April!

Friday, February 13, 2015

Update - February 13, 2015 - The Cold

 In the post I did on Monday (click here) I continued to discuss the cold that I had been expecting.  I  centered the arrival on Valentines day and that appears to be right on track.  In the previous thinking I was expecting about a 10 day stretch with a few days in between of warmer weather.  Even though the computer models have NOT been consistent on the arrival of the cold, I have held steadfast.  Even this morning the models are not that cold.  BUT, I firmly believe we are heading into a cold stretch that may actually last longer than 10 days.  The coldest during that stretch may not be until next weekend, or thereabouts. Yes, there will be a day or two thrown in that "milder" air will briefly return across the High Plains.

Looking at this mornings temperature map the notable cold has shifted east across Canada.  The signal really doesn't support the cold into Kansas, yet.  Initially what will happen is the cold front that moves in tonight and early tomorrow will bring colder air in from the east.  Thus, eastern Kansas will be colder than the high plains. (click for a larger version)

Before I go into more currents and the extended, I thought I would share a graph of the ridiculously mild temperatures we had in Dodge City centered on last weekend.   Although it wasn't the warmest stretch for the winter months (for Dodge), it was certainly significant.   It's interesting that in the record books all these long and mild stretches occurred in February.


Looking at the morning satellite of the western U.S. and eastern Pacific, there are several important features.

The first feature is the "L" over the Baja of California.  This is the system I discussed in the previous blog that was to bring a little precipitation to Colorado and near the high plains.  It dropped south through Colorado and now moving southwest to the current position.  It brought pretty good snow and rain and even a little rain into west Texas and the Panhandle.  I don't think this will impact Kansas now that it is were it is.

Another feature is the X headed towards the Pacific Northwest which will help bring in a second front on Monday.  Precipitation with that feature should be confined to Colorado but with a second area forming across eastern Kansas and into the Tennessee valley.

The other significant feature is the "L" that is denoted on the left hand side of the image.  This Low and trough aloft will help pump up of the jetstream and ridge that will eventually unleash some really cold air into the states later next week (and could help bring a day of milder air to the high plains).

Now some of this cold air may initially be modified because of a lack of snow cover across the northern plains.

But with each system some of that bare ground will get a dusting.  The following map is the expected snowfall expected through Monday morning.

Beyond the first of the week the pattern will become complicated and hard to pinpoint. There will be a chance for a least light snow across the plains, but with some amplification there just might be a more significant storm.  I would not expect that possibility until late next week. 

Looking a little further, this cold and unsettled weather may linger into the end of the month. 

More next week.

Monday, February 9, 2015

Update Feb 09, 2015 - Where is the cold air?


As expected this past weekend was ridiculously warm for February with high temperatures on Saturday in the mid 70s to mid 80s across the high plains.  Sunday was a bit cooler but still warm and today (Monday is still on the mild side).  There were daily records set.  But, 80 degree days in February is not that rare as it happens, on average, about once every 7 to 10 years.  So, I would say more unusual than rare.

So where is the cold air I've been discussing for a month or so?  In the last blog, click here, I showed a current temperature map of Canada.  It's amazing, but the map of 2 PM CST temperatures today is just about a mirror image!  Check it out!  Click here for the map from Thursday afternoon and compare it to this afternoons below....

The cold air source is there, it just hasn't moved any.  Part of the reason the cold air hasn't started south is a strong storm moving into southwest Canada from the Pacific.  You can see this storm on the satellite image below...

The storm is broken in two parts but both have forced the jet stream northward.

This storm will turn east and then southeast into the Great Lakes during the next 2 to 3 days.  It will bring snow and ice to the far northern plains and Great Lakes and into the northeast U.S. once again.  Much of the northern plains which does not currently have snow cover will miss out.

The following was the snow cover across North America as of this morning.

Alright, now what about this cold air....  In the blog I did last week I mentioned the cold would arrive during the February 12-16 time period.  At that time the computer forecast models where not even hinting at cold.  In fact, some where keeping mild readings into the last part of February.  But, based on the cycling of the pattern, the extended East Asian Jetstream and the possibility of a storm along the Japan coast, the cold scenario is likely!

In quite a few of the previous posts (please go read them if you have time) I even mentioned that the cold by mid-February could be the coldest of the season.   That is still a possibility.  But even so, what is still very likely is the return of the brutal Arctic air, regardless that the models are not picking up on it.   I'm sticking with my Feb 12-16 period, centered on Valentines Day.   Once the cold arrives there will be about a 10 day period of the cold, but maybe a day or two in between of slight recovery.

As far as precipitation, there should be one or two events during the cold period - which would likely be of the frozen or freezing variety.

I know calving will commence soon for a lot of folks and it just might be during this cold stretch.

I'll attempt an update later this week.

Thursday, February 5, 2015

Update Feb 5, 2015 - Another warm one!

I about choked from laughing recently as I had several people seriously ask me if winter was over for western Kansas.   Hey, warm days come and go this time of year.  Winter "officially" ends later in March during the spring equinox but for North America that really doesn't mean much.  I assure you, there is plenty of winter weather yet to be unleashed.

Another major warmup is in store for this weekend.  I bet there will be plenty of folks on the links, in the yard and maybe even in the fields.  Hopefully homeowners don't get a crazy idea to scalp their fescue or bluegrass lawns this weekend.  I actually saw that happen two weekends ago!  Why not cut?  Because there is still a high probability of very cold Arctic air and the roots will be susceptible to extreme cold causing damage!

I've been advertising the return of an extended period of Arctic cold starting as early as the 2nd week of February.  In the post I did on the 2nd, I said more likely in 10 to 14 days.  That would make it the 12th - 16th (or starting the last part of the 2nd week, right?).   Even though the computer generated forecast models STILL aren't advertising this possibility, I'm still seeing the writing on the wall. 

Looking at the latest satellite image, the flow is characterized as chaotic.  First, the East Asian jet stream has expanded all the way across the Pacific.  This is an unstable configuration.  Second, the flow across the higher latitudes is rather bizarre (see map).  This may have more to do with the weather regime being in what is called a Modoki (pseudo El Nino). It's really strange!  Also, there are numerous upper level disturbances in the flow, most of which are aimed at the west coast.  On the map they are denoted by the red X.  (click on the image for a large version).

Over the next 7 days these storms will hammer the coast from central California to Washington, bringing copious amounts of precipitation.

Some of this energy from the upper level disturbances across the Pacific will drop southeast and then south and produce an unstable flow over the southern Rockies.  In turn, some of this change may very well bring a little rain or snow to the high plains by mid-week (10th - 12th).

That gets us close the period of Arctic air.  As East Asian jet stream buckles the Arctic air should start moving south.  There is already a cold air source (and getting colder).  Look at the Thursday afternoon temperatures!

There is also a storm advertised to form across the far western Pacific, near the eastern Asian continent coast.  Usually, this leads to downstream amplification of the jet stream, which in turn would support the flow to produce much colder weather.

Next week I'll update my thoughts on an increasing probability of a wetter than average late February and March.  Hint - I'm slightly more optimistic than early thinking.

Monday, February 2, 2015

Update - February 2, 2015

In the previous post I did on January 20, click here, I discussed a weather system that was going to impact much of the southern Colorado and into Oklahoma and Texas bringing a lot of snow.  Indeed that did occur, only shifted slight south and east. Click for a large version.

The snow also had a decent amount of moisture in it and will help with short term drought conditions.  But, for the long term very severe drought conditions continue.  The following is the latest drought monitor map:

More recently,  another wet system moved out of the southwest U.S. and combined with an upper level disturbance that had moved out of Canada (and eventually produced near historic snows around Chicago and now - as of Tuesday - heavy snow in the northeast U.S.).  The result of the combination of the two storms produced widespread rain (and some snow) across much of the high plains and especially Kansas.  Click for the largest version

In recent blogs I was discussing the warming that was expected into the last part of January.  The warming the second part of the month pushed the monthly average at Dodge City to above "normal".

In addition, I also discussed the return of brutal Arctic air during the 2nd week of February.  Although there has been a couple of intrusions, those have lasted only a day or two.  What I'm referring to will be an extended period of Arctic air.  So far the computer models have not caught on but I'm still confident that it will happen.

Looking at the latest satellite image, the upper flow across the Pacific is rather bizzare and chaotic. 

Most notable for me is the increasing moisture laden flow that is headed towards the west coast.  With time this should shift south and bring heavy rains (and mountain snows) to at least the northern half of California.  For the high plains, the bizarre flow across the central and northern Pacific should settle down and eventually amplification will take place.  As a result, changes in the flow will lead to a more serious Arctic plunge.  I'm going to hold on to this happening in about 10 to 14 days.  

As far as moisture for the high plains, it looks slim for significant amounts for at least a week.

I'll update later this week.