Sunday, December 28, 2014

Update - December 28, 2014

In the last post (click here) I discussed several things.  One was the opportunity for a little snow across the high plains (2 to 4 inches) for Friday into Saturday, but with a lot of uncertainty of the location.  Again, it's very difficult to impossible to pin point amounts or location when it's several days or more out.  In advance of the minor storm that produced the snow it warmed up considerably on Christmas Day with many locations reaching the 50s and 60s.  The snow that fell was concentrated in two locations across the plains. See the map below...(click for a larger version).

Attention now turns to a extreme Arctic outbreak, one that has been predicted for some time.  As of Sunday afternoon the leading edge was moving into the Dakotas.

Looking at the satellite, the polar jet stream was making a plunge into the U.S. and the cold has only one to go...SOUTH!  By Tuesday temperatures will have fallen into the single digits across most of the high plains (and perhaps below at a few spots).  Readings will stay primarily in the single digits during the day and with stiff north winds the wind chill index will be in the dangerous category.  There is even some evidence that temperatures may not get much above zero at a few spots.  Even with not much clearing Tuesday night it appears readings will fall below zero at many locations (see maps below). 

BTW, those temperatures you see on the above map?  That is NOT the wind chill index, it is the air temperature!

Snow will accompany this cold outbreak.  The liquid to snow ratio will be high so it should be a pretty fluffy snow.  I have high confidence of 1 to 4 inches across much of the high plains.  Details of course this far out are impossible so stay informed through the NWS website

Wednesday, December 24, 2014

Quick update - 12/24/14 - Get ready for an Arctic intrusion

Current Weather

As I discussed in the previous post (click here) I was anticipating a significant storm east of Kansas.  As far as snow, not so much.  But the current storm along the Mississippi Valley produced killer tornadoes yesterday (Tuesday) in the south and now extreme turbulence over the midwest. This is impacting travel by air with significant delays being experienced.  There will be snow across the Great Lakes though.

The other feature that I discussed in the last post was the system that at that time was northwest and west of Hawaii.  It was anticipated that it would cause some issues as it approached late in the week.


This feature that had been north and west of Hawii is now (as of Friday afternoon) diving into southern Oregon and extreme northern California, as seen in the satellite image.  Click for a larger version.

This X that is depicted on the map will intensify as it dives southeast into the Rockies.  There is still a lot of uncertainty in the track and amplitude.  However, just as expected in the previous post, the surface response will cause much warmer temperatures across the high plains on Christmas Day.  Enjoy those temperatures as that will be a distant memory very soon.

As the surface and upper systems organize it appears that precipitation will develop late Friday and into Saturday.  There should be a quick change over for much of the plains, with accumulating snow expected.  But as is typical, it's impossible to pin point where and how much.  Again, keep checking for the most up-to-date forecast.  I think it's reasonable to expect a 2 to 4 inch band with this system - but the where just can't be forecast this far in advance.

The Cold

As I've expected for some time (go back to the previous posts) the Arctic cold is still on schedule.  In the post I did Monday I threw out numbers of 20 to 30 degrees below normal. I'm gaining confidence on the cold and there is pretty good evidence that by the middle of next week we could be looking at some VERY cold temperatures!  Specifics will depend on snow cover, sky cover and wind.  But there is the potential for lows much below zero across a large part of the high plains.  There could even be daytime temperatures around zero or colder and with wind producing life threatening wind chill readings! Those with livestock interests should prepare for very harsh conditions.

The map below is just a guess, but depicts a strong possibility.

I'll try for an update on Sunday.

Merry Christmas!

Monday, December 22, 2014

Update 122214 - Get ready for the cold

I've been trying to figure out the cycle length and orientation of this years weather pattern and I "think" I have it figured out.  If I've got it right, then expect a pretty severe cold spell starting later this week and progressively getting worse into the first of the year.  Before I discuss that, I want to look back at what recently happened (and is currently on-going).

Past Weather

In the last post on the 16th (click here) I discussed the possibility of snow across much of Kansas.  Indeed it did materialize.  The heaviest amounts were in a stripe from northern Clark county to north central Kansas.  Local to the Dodge City area the most reported was 6 inches near Belpre.  Much of western Kansas only saw a dusting to nothing at all.  Click on the map for a larger version.

In addition to the forecast of snow, I discussed the likelihood of Arctic air returning for the last part of December, plus the hunch of a high impact storm around Christmas.   That is still on track.

Current Weather

As of today (Monday) there was an organizing storm just north of Kansas City.  Widespread rain was falling across northeast Kansas.  There were sprinkles across the western part of the state.

This storm was evolving and deepening with another shot of energy diving southeast across the western high plains which will develop into another storm, east of Kansas.  By Christmas Eve there should be a very strong storm impacting much of the eastern half of the country.  The combination of the two storms mentioned will bring travel headaches to the country.  If you're traveling by air on Christmas Eve or Christmas Day, expect major delays!

Behind these two storms there will likely be a dump of Arctic air into the country.  Looking at the current surface chart from Canada, there is very cold air building up and headed this way.

I've mentioned in several previous posts about trying to figure out the repeating pattern cycle length.  I think I've got a pretty good idea.  If my calculations are correct, then an extended cold period is likely, starting right after Christmas and continuing into the first of January.  The cold could be 20 to 30 degrees below normal. That would mean lows in the single digits to perhaps below zero, and highs in the teens and 20s.

What about moisture?

Looking at the satellite map below, there are several features to point out.

The first is the low that is currently north of Kansas City.  This won't have any impact on the high plains but has been bring the rain discussed above.  The second feature is really not depicted on the map but is essentially a very strong jet stream that will be diving into the deep south bringing the travel impacting storm by Christmas eve, but east of Kansas.  The third feature is the X north and west of Hawaii.  This will be our next weather maker as it will be approaching the plains late Christmas day and into Friday.  It's impossible to predict the strength or location (and track) but it should have an impact on travel across the plains.  In advance of the system, it will cause of surge of  mild air to head north with above normal temperatures possible across Kansas for Christmas Day.  But as the system moves out of the Rockies, it is likely that cold air to the north will be tapped so that there should be wintry precipitation with it.  I just can't say at this point if it will be Nebraska, Kansas or Oklahoma.  Stay tuned.

Another feature is the big blue H over the Pacific.  This is an upper level ridge that will intensify and build into western Canada over the next week.  Depending on the amplitude, a very cold airmass is likely to drop into the states.  This cold will be similar to what happened in November.  Anytime an Arctic airmass resides over the states, any minor disturbance in the flow aloft usually results in some sort of precipitation.    I think the end of the month and into the first of the year could get rather interesting.  I'll attempt to update this again soon.

Tuesday, December 16, 2014

Update - 12/16/14

Past event

In the last post I did on the 8th (click here) I discussed the potential for a storm a week away.  That storm did materialize and brought widespread precipitation and even at least 3 tornadoes to Kansas and Oklahoma.  If you didn't get a chance to see the tornado video in Harper county, it can be viewed here.  There was at least one other tornado in Harper county and also at least one in Oklahoma.  Tornadoes in December in Kansas are rather rare, occurring about every 10-15  years but usually east of I-35.

In the cold air of northeast Colorado there was up to 12 inches of snow.  Elsewhere in Kansas there was quite a bit of rain in some areas.  (click for a large version)

This was the second mainly rain event in Kansas this month.  For December that is just a bit unusual but also rather typical for an El Nino type winter.  The cold we saw in November WILL eventually make it back into the central U.S., it is just a matter of time.

The precipitation that has fallen this month is certainly good news but there are areas that are still missing out.  The U.S. drought monitor map shows areas that are still exceedingly dry (although the map does NOT take into account the precipitation that fell this past weekend).

For Dodge City in particular, even with above normal precipitation for 2014, the ongoing long term dryness can be seen in the graph below.  That graph shows the deficit of moisture that has been in place since October of 2011.

The current atmosphere

As of this Tuesday morning there was a fair amount of snow cover across Canada and parts of the northern plains.   The good news out of this is the snow accumulations across the drought stricken west.  There has also been copious amounts of rainfall in the lower elevations out west going a long way in reservoir storage and relieving much of the drought.  Back to the snow cover, it is about normal for this time of year.

Looking at the satellite image, there are several important features.  One is the anomalously strong jetstream across the Pacific, meaning wind speeds aloft area VERY fast. This type of setup is unstable and usually leads to downstream amplification of weather systems.  This is NOT the first time we've seen this during the this years fall and winter.  There are several upper level lows or disturbances denoted on the map.  The most important for the near term was the X that was approaching California and the other feature, an "L" just west of the Oregon/Northern California cost.  The X will be approaching the central plains late Wednesday and into Thursday.  The "L" will eventually drop southeast and affect southern Texas.  However, the X system will enhance the opportunity for freezing rain and snow across much of the central plains.  The track of the surface response is in question (as is the exact track the upper system takes).  Somewhere across Kansas there could be a stripe of 1 to 4 inches of snow with freezing drizzle or freezing rain across Oklahoma and perhaps south central and southeast Kansas.  The local updated forecast is the best bet to keep on top of that information.  Go to and click on the part of country you're interested in for the local NWS office forecast.

The future

I'm not real confident on the eventual evolution of the flow aloft with so much going on across the Pacific.  However, if you go back several posts, I've discussed the likelihood of Arctic air returning for the last part of December.  I need to analyze the repeating pattern and see if I can determine the cycle length.  I've got a pretty good hunch that there will be a high impact storm around Christmas with a dump of Arctic air about the same time.  If you're traveling by air across the county around that time, be prepared for unpleasantness.  I'll try and get additional details later this week so keep checking back.

Monday, December 8, 2014

Update - 12/8/14

This will have to be short due to time constraints...

See the previous post by clicking here.  In the outlook portion I gave reasoning for a precipitation event that was hammering California and some of that "wave train" energy would make into other parts of the country.  Indeed  many areas were fortunate to receive very welcome rains (thankfully not snow with wind) late last week.  The map below is a crude analysis of amounts, some very generous!

I also discussed the relatively "mild" weather expected through at least the 13th with any major changes waiting until mid-month.  That is still on track. There are some pretty decent signals of a significant storm developing this coming Sunday/Monday across much of the middle part of the country (Dakotas to Texas) with the most likely area centered on Oklahoma and Texas.  As the storm organizes I'll be able to pin point the details so I'll post again towards the end of the week.  Wintry precipitation is not out of the question on the cold side of the storm, but there are way too many uncertainties to guess where that might be at this time.  Check back later.

The Weather Prediction Center forecast of precipitation during the next 7 days....
Even though I can't give a lot of details on this potential developing storm, if you're traveling late in the weekend or early next week, you will want to keep checking forecasts (and they no doubt will change as we get closer).

Returning Arctic air for later in the month is still on track too.  More on that later.

Monday, December 1, 2014

Update - December 1, 2014

 **** the original post was accidentally deleted - so if you saw that, this post might be worded differently ****

Happy first day of Meteorological Winter!  BTW, unlike astronomical winter than runs from December 21 through March 21, Meteorologists define winter as December 1 through February 28, often referred to DJF.

A look back

Back on November 4th, I started mentioning the possibility of a high impact storm that could occur around Thanksgiving.  At that time (and in later posts) the location of such a storm was in doubt.  The storm finally did materialize but impacted the eastern states and up into New England.  If you traveled by air last week, did you experience issues?  The storm dumped large amounts of snow and did impact commerce and air travel nationwide (that had connections to one of the major hubs).

Forecasting a significant storm several weeks in the future (in this case about 3 weeks) is difficult at best.  But, the spatial accuracy is almost impossible, especially for the first few storms of the fall.  After a pattern is established and starts to repeat the accuracy of the location of such storms will improve.  But is this even usual information if the spatial accuracy is lacking?  In this case just knowing that there would be travel delays by air should of helped.

Behind the storm of last week a build-up of frigid air across Canada began to race south into the states.  The low temperatures for Monday morning were very cold behind the Arctic front.

This cold came on the heals of a ridiculous warm spell. Ahead of the Arctic front very warm air descended from the high terrain of the southern Rockies (called adiabatic warming) and spread across the plains.  At Dodge City the high temperature of 78 and 79 on Friday and Saturday (28th & 29th) was the third warmest two day period for late November since records have been kept.   This was the second time in less than a month that record warmth was followed by very cold temperatures.  I would bet this will occur again sometime this winter.

Looking ahead

The jet stream across the northern hemisphere is active, but changing.  There are three features that have caught my attention.  One feature is the "wave train" of energy that is propagating from the Asian continent in an arcing manor into the eastern Pacific west of California.  This downstream propagation of energy is referred to as a Rossby wave or a planetary wave train.

I've highlighted this occurrence on the following map showing the arcing nature.

This wave train is likely responsible for the storm that is bringing MUCH needed precipitation to drought ravaged state of California.   Some of the affects of this will be moving into other areas of the U.S. during the next 5 to 7 days.  The Weather Prediction Center (WPC) has the following possible outcome through December 8th.  Much of the precipitation will be liquid (except for the higher elevations).

Back to the Dec 2014 500hPa map above....another feature that is important is the big red L over the Hudson Bay area and the associated circular flow around it.  This feature has been rather persistent so far this fall and I fear that it may be dominant this winter.  The reason for the "fear" is that is will unleash Arctic air periodically.  The Arctic air will become quite intense due in part to the other big red L associated flow around it that has be parked over Siberia.  If the Hudson Bay feature becomes the dominant contributor to our weather, then a cold and dry winter can be expected for much of the eastern half of the country with the high plains on the western fringes.

However, the wild card in all this will be the flow across the Pacific. There is another feature currently that is contributing to this weather pattern.  This feature is referred to as a Madden Julian Oscillation (MJO).  I recommend that you take a minute and read a FAQ on the MJO by clicking here.  If you're bored and need something to read, take a look at detailed information on the MJO by clicking here.  

Often an MJO causes coherent changes in the jet stream from the tropics into the mid or high latitudes, across BOTH hemispheres.  Look a the map below.  This is a satellite image and I've highlighted the flow from the tropics.  Notice how the flow is mirrored across the equator into both hemispheres.

I believe the "wave train" I discussed earlier in this post and the coherent MJO signal could both be indications of an El Nino response.  If this is true, then the contributions from the Pacific will become more pronounced and continue into the deep of winter.  Combine this with the semi-permanant Hudson Bay circulation and suddenly we're back to the below normal temperatures and above normal precipitation that the previous winter outlook was indicating.

So, for the balance of this month, the weather pattern will be relatively "mild" through at least the 13th of December (with a few minor cold shots - but also mild periods).  Any major changes will likely wait until mid-month.  I'm seeing some indications of another significant shot of Arctic air, especially during the last 10 days of the month.  I'll be watching closely for the signal because if it does come to pass, there could be serious cold issues across much of the central part of the country, including the high plains.  Serious = lows 10 to 20 below and highs around zero to single digits.  That type of cold combined with any contributions from the Pacific could could result in a major storm.

Monday, November 24, 2014

Where is the Thanksgiving Day storm?

For about 3 weeks (look back in the past three posts) I had discussed a possible storm around (several days before to after) Thanksgiving.  In the blog I did last Friday (click here) I talked about the anomalously strong jet stream extended across the Pacific and how it would likely amplify (buckle). That process is starting to happen as of late Sunday night.

I had a feeling that with this buckling that there would be major cyclogenesis (deep low developing) somewhere from the central part of the country to the east coast.  It often is impossible to predict this location much in advance, until a pattern is established and starts to cycle.

On the following satellite image, you can't see the storm that brought rain and much warmer air to the snow battered Buffalo, NY area.  Another weaker small storm (denoted by the L) was moving through Illinois and will bring additional precipitation to western New York.  The two lines with arrows indicates the positioning of two branches of the westerlies (jet stream).  The one in red is the result of the buckling of the extended jet stream noted above.  The second blue one is the polar extension of the jet stream.  The two X's represent energy in the flow that will become the first of two storms.

It now appears that this buckling will result in several storms instead of just one major one.  The first will bring heavy snow and wind to the western Great Lakes late today and tonight (24th).  The second will amplify into the Mississippi Valley and eventually deepen and move up the east coast.  If you look at the Weather Prediction Center's precipitation forecast of precipitation for the next 7 days there is a swath of heavy precipitation on the east coast.  That leaves the High Plains region without much of anything!

WPC precipitation forecast

Early on it appeared pretty likely that Arctic air would make a return visit late this month behind these potential systems.  The cold air is in place behind a strong cold front, but it now appears that much of this cold air will move southeast instead of south.

Map of the current location of the Arctic air and fronts.

It is amazing that the various numerical weather prediction computer models have been all over the place regarding impacts from the evolution of this pattern.  One in particular from the European weather center (ECMWF - it's generally the most accurate) had been indicating possible snow across the central plains for Thanksgiving.  Now it is indicating very mild conditions for Thursday and Friday.  Another model that goes 6 to 8 weeks into the future was indicating a very cold stretch of 7-9 days, starting Thursday.  But it too has backed off considerably.

Another long range computer model's output showing the cold for Dodge City....

Thankfully the above forecast output is not likely to verify - at least this time.

I think the story line is that until the pattern starts to repeat and cycle, it will be tough to have much lead time on any systems.

More later...

Friday, November 21, 2014

Update - November 21, 2014

Finally the Arctic November chill has moved out of the high plains, although with low clouds and fog it was still rather chilly across the eastern high plains Friday afternoon.  The Arctic cold that we endured was one of the top 3 coldest periods for November.   The average temperature at Dodge City from November 11-17 was only 21.3 degrees, or about 23 degrees below normal!  This is the 3rd coldest 7 day stretch in November for Dodge City, since records began in 1875.  The 2nd coldest 7 day stretch was in 1952 when the average temperature was 19.8 degrees.  The coldest was way back in 1880 when the average was as astonishing 11.4 degrees (November 16-22)!  Compare that to normal which is 44 degrees!

Snowfall across the plains last weekend from 2 separate systems ranged from  less than one inch to 4 1/2 inches, depending on your location. 

From the post I did on the 7th of November and the one I did on the 19th, I discussed a potential major storm around Thanksgiving.  Any thoughts of WHERE this might occur was up in the air as the system was not showing up on any numerical weather guidance and really not showing up on analysis products.  As of Friday (this writing), I still don't have a real good feel for the development or placement.  For a few days the European forecast model (ECMWF) did have a system for next week - and it's usually the most accurate that is available to view.  However, during the past few iterations it didn't have anything.

On the map below the most notable feature is the very strong and anomalously strong jet stream across the Pacific ocean basin.  This configuration and magnitude is very unstable.  In most cases as this unstable and energetic jet breaks down, chaos ensues in the form of rapid intensification and downstream amplification of the upper level winds.  During the cold months this usually means a significant storm.  But the $10 million dollar question is exactly when and where!  Numerical weather prediction models are all over the place and therefore are of no help.

Satellite image showing the strong jet (red arrows)

Friday afternoon there was a rather significant storm over Arizona which will bring widespread rain to central/east Texas and eastern Oklahoma and into the Mississippi Valley.  Then eventually heavy rains on the east coast.

The Weather Prediction Center of the NWS offers this solution over the next 7 days....
As far as the Thanksgiving storm...I just don't know yet.  If it is going to show up as an organizing storm, it might not be until Monday or Tuesday.  But when it does start developing it might do so very rapidly.  Right now my gut feeling is that it will affect areas from Chicago to the northeast or New England areas.  If you will be flying then you should probably expect delays.

I'll try and follow up on Monday and see what is showing up.  Earlier this fall I talked about repeatable weather systems, once they establish themselves in the Fall.  I'm not finding that repeating system, yet.

Enjoy the first half of the weekend.  Colder (though not Arctic cold) temperatures are in store for Sunday/Monday.

Wednesday, November 19, 2014

Update - November 19, 2014

Probably the biggest news during the last few days is the absurd amount of lake effect snow that the eastern Great Lakes has received and will continue to receive.  Google "lake effect snow 2014" and look at some of the crazy photos and video!  As of this afternoon there were observers that had already picked up 6 feet of snow and more was on the way.  The most awesome time lapse I've witnessed can be found here.

Back to high plains weather....

The temperature at the Dodge City airport on the 10th of November rose to 80 degrees at 1245 PM but had fallen to 22 by midnight, and 16 by Tuesday morning.  That's ridiculous! The brutal change from a relatively mild Fall to Winter that was ushered in on the heels of the November cold is letting up a bit.   A few more brief surges of colder air can be expected during the next 5 days (intermixed with mild temperatures).  At least there has been a warmup.  However, the warmup has been and will be tempered by snow cover.  The map below shows what the snow cover that was observed on the 18th.

If you read back on the past few posts, I discussed the pattern shift that caused this outbreak of cold.  Basically the change that took place has locked into place. This bothers me a little bit.  I was expecting this shift to occur.  But, I did not expect that particular pattern to persist this long (at least for now) and the longer it does persist the more likely that it will repeat often into the deep of winter.  The upshot of that scenario is a tendency for a cold and dry winter (below normal temps, below normal precip).

On the satellite image above, the blue line with arrows denotes the polar jet stream, capable of bringing Arctic air into the U.S., which has been ongoing since the 10th.  If that persists, then there will be periodic Arctic fronts sweeping across the country (and High Plains).   The issue for now is the blocking that is anchored over western Canada.  First, it is preventing the moist Pacific jet stream from entering into the country from the west.  Second, it is allowing the persistence of the polar jet to be in the same configuration.  That blocking should break down soon.  However, as it does break down the jet stream may reconfigure in such as fashion as to bring additional cold to the U.S., with a threat of precipitation, especially if it shifts westward.

In the blog I did on November 7th (click here for that discussion) I stated "the atmosphere should reorganize and re-energize and then could unleash some nastiness around Thanksgiving.  There is a small signal of a high impact weather event  during the last 5 days of the month.  The only problem, I don't know if it'll be in the central plains, midwest, or north.  I'd bet though that there will be travel issues across the country about then."  That is still a very real possibility, even though the long range computer forecast models from the U.S. shows NOTHING!  Even if the high plains misses out on a potential storm, there will likely be another outbreak of Arctic air.  I'll update Friday or next Monday.

Beyond next week there are signals to high impact events the first 10 days of December, especially for additional cold.

Wednesday, November 12, 2014

Quick Update - November 12, 2014

Go to the previous link here where I discussed this brutal cold we're experiencing for November.

The high temperatures today (Wednesday the 12th) where record setting at many sites.

Plus, the mercury may not rise much above freezing right on through the remainder of the week.

There is still a lot of uncertainty about the weekend weather.  I, unfortunately, have other obligations and cannot update much more at this time.

Friday, November 7, 2014

Update - November 7, 2014

I hope everyone is ready for the cold!  In the previous post (click here) I mentioned the cold coming up for this next week "By the middle part of next week high temperatures may be in the 20s/30s and lows in the single digits to teens".  This post I'm writing today is an update to those thoughts.

As expected, the remnants of what was once Typhoon Nuri is transitioning into a super deep and extremely strong ex-tropical low across the Bering See/Aleutian islands.  The video below shows the wind pattern with that system and with other weather systems.  Click on the video to play.


There have been forecasts of winds to be up to 100 MPH and wave heights well in excess of 50 feet (some estimates near 100 feet if that can be believed)!  This intense storm up there will force warm air north into the Arctic.  The frigid air up in the Arctic as of today (Friday) will therefore be forced south, right towards the U.S..  Additional downstream propagating energy will also produce other mechanisms to displace the cold.  So, the result for us across the high plains will be an end to the relatively mild Fall and the start to winter conditions.  Most of the impacts this time will be from the cold and not snow or ice.  Yes, there could very well be a little snow during the stretch of the cold but amounts, if any, should be minimal.

At 9 AM this Friday morning the cold air was already headed south but at a slow and steady pace.  Temperatures across northern Canada were around 15 below zero (that is not wind chill).  The front that was the leading edge to the winter cold will arrive across Kansas sometime Monday.

The following video is output from one of the global forecasting computer models that generates a simulated forecast.  This one shows the invading cold, but don't get caught up in the numbers.  It is actually too warm! 


Temperatures by mid-week (~12th) may struggle to get out of the upper teens and 20s for highs! Lows will dip well into the teens and single digits at some locations.   Although there may be a brief warmup (warmup may be misleading) Friday or Saturday, a second and perhaps even colder airmass could invade the area Sunday and Monday (16th-17th).  One of the long range global models has temperatures down to 5 to 15 below zero as far south as southwest Kansas!

Beyond this next 7 to 10 day period the atmosphere should reorganize and re-energize and then could unleash some nastiness around Thanksgiving.  There is a small signal of a high impact weather event  during the last 5 days of the month.  The only problem, I don't know if it'll be in the central plains, midwest, or north.  I'd bet though that there will be travel issues across the country about then.  I'll update that  possibility at a later time.

Tuesday, November 4, 2014

Update - November 4, 2014

I've been a professional Meteorologist since 1983.  The first six years were in the private sector where I was manager of forecasting operations and the remainder working for the National Weather Service (in Des Moines, IA and in Dodge City) where I've been both a Lead Forecaster and a Warning Coordination Meteorologist.  In those years I've gained a lot of experience.  One of my life's experiences is that once I make a forecast and it's my gut feeling, I stick with it!  Don't change that initial forecast!   Well, I'm breaking that wisdom.  If you go to the outlook that I issued on October 23 (click here for that discussion), you can see my outlook at the bottom of that post.  I've already made a tweak to the temperature forecast for the winter months of December, January, and February.  I'm already seeing some signs that the cold may dominate early on (not sure about late winter yet) so the average for the 3 months may be colder than originally thought.

Updated forecast made on November 4, 2014
The initial temperature outlook can be viewed by clicking here.

I've left the precipitation forecast as is.   BTW, at our office we have a "guess how much snow will fall" and I guessed 29.8" of snow at the Dodge City airport from November through May.   Totals will be highly variable across the plains though.

One of the reasons I'm leaning more towards the cold side is that vast amount of snow cover that is already across Eurasia and Siberia.  It is reportedly the most seen since the mid 1970s!  Usually this does not bode for a mild/warm winter across the U.S., and since I was already expecting  a pattern conducive to cold, I just had to make the adjustment.  The following map shows the snow and ice cover across the northern hemisphere as of November 3...

You might notice the lack of snow cover across North America.  Despite the record setting snows across the eastern part of the country late this past weekend, the overall snow cover across the U.S. is actually a little less than normal.  Also, there really hasn't been extremely cold weather yet (except for the far east and southeast part of the U.S.) and in fact much of the western half of Kansas has not had a "killing" freeze!  But, that is about to change and change big!

If you follow the weather at all you may have heard about the super typhoon across the western Pacific south of Japan.  Nuri is it's name and it is quite powerful for so late in the season.  As Nuri heads north it will interact with a anonymously strong jet stream and will become an extremely deep and strong ex-tropical cyclone as it heads towards the Bering Sea.  In fact there are predictions of wave heights of 50 feet possible in the Bering Sea.  WOW!  This powerful storm and the track will help force a shot of very cold air to head south into the U.S. in 7 to 10 days (probably closer to 7).  This cold air will likely spread  deep into the plains and midwest.  By the middle part of next week high temperatures may be in the 20s/30s and lows in the single digits to teens, at least that seems a distinct possibility.   The way the NWS operates this may not show up in the forecast until a few days out - it will likely just be a gradual trend towards colder.   There does not appear to be much chance in the way of precipitation though.

The following satellite image shows the feature I'm talking about...

A look at recent precipitation and the drought

Late Sunday night and early Monday there was a bit of precipitation that moved out of Colorado and New Mexico and into Kansas.  The amounts were generally very light except down in New Mexico.

For October the rains were a little more generous for many folks, but lacked significantly for others.  By far the greatest amounts were across eastern Kansas, Oklahoma and into the Mississippi valley.  Click for a larger version.

At Dodge City the total was above average.  The following map for October precipitation has a different color curve than the one above but it shows the high plains a little closer.  Click for a larger version.

The drought continues across much of the western part of the country and also across parts of the plains.  The winter months are not a good time to improve on the drought since it's the driest part of the year, historically.

One final thought....Thanksgiving.  I've got little hunch that there will be a very high impact weather event around that time, somewhere across the central plains into the midwest.  Obviously this is quite a ways out but it is something I will be watching carefully.  Historically the highest threat for a blizzard across western Kansas is during three periods:  1) November 20-30, 2) January 1-5, 3) March 18-22.  This is only based on climatology.

I'll try for another update next Wednesday.

Thursday, October 23, 2014

Outlook for the fall and winter - 10/23/14

This will be long, because I'm going to explain a lot of things.  If you want to cut to the chase (not recommended because I want to explain some reasoning), then scroll right to the bottom.

If you go to the internet and Google "winter weather 2014-15" you will get dozens and dozens of outlooks for this coming winter.  Are any correct?  Possibly, but there are so many opinions out there, some not even based on science.   I WON'T post the fictitious map that came out about a month ago that was released by a satirical web site and unbelievably was shared millions of times on social networks as if it was a "real" outlook.  There were even decision makers ready to jump on it - which is very scary in my opinion.

By the way, you can click on any image in this post for a larger version.

I chuckle at the Farmer's Almanac outlook on the left.  It's going to be frosty at Brownsville, Texas?  Apparently in this large block of states (NM, TX, OK, AR, LA) the weather will be the same?  I guess if one spot verifies, they all verify.  They claim 90 percent accuracy over the years.


I'm going to go ahead and offer the "official" winter outlook produced and posted by the fine folks at the Climate Prediction Center.  If you want to take the time and read their reasoning, then click here.  I don't necessarily agree with their assessment as they tend to go with persistence and composite analogs, that rarely verify.

CPC's precipitation outlook for the winter
(December, January, February)

CPC's  temperature outlook for the winter
(December, January, February)

NOTE:  On the CPC maps above, the "equal chances" DOES NOT imply normal conditions!  It simply means the forecasters did not have enough confidence to state an outcome.  Probabilities greater than 33% indicates the direction they (forecasters) were leaning.  Example, the >40% in the warmer shaded area is leaning towards above normal temperatures. 

A little background on extended outlooks

For the High Plains of Kansas the climate is characterized by highly variable conditions, both in short and long time periods. The proximity to the Rocky Mountains and the Gulf of Mexico moisture source are just two of the reasons for such variability.  But it is much more complicated than that. There are numerous intra-seasonal, multi-seasonal, multi-year, multi-decade and even multi-century ocean/atmosphere cycles that have influences on our weather.

Interactions with land masses, oceans and the sun are what drives our weather. Understanding these interactions can help (or hurt) long range forecasts.  Because of millions and millions of interactions across the globe and the fluctuation of the suns energy, forecasts beyond just a few days can suffer in accuracy.  So, ANY seasonal outlook can be WAY off!  The following are just a few of the tele-connection cycles and oscillations that impact our weather (and feel free to Google these for an explanation of each):

The Madden Julian Oscillation (MJO)
Global Wind Oscillation (GWO)
El Niño/La Niña - Southern Oscillation (ENSO)
North Atlantic Oscillation (NAO)
Arctic Oscillation (AO)
Pacific Decadal Oscillation (PDO)
Atlantic Multdecadal Oscillation (AMO)
Solar cycles (this could be a HUGE player in the next couple of decades)

A friend of mine from back in my college days at the University of Oklahoma (BOOMER) and I had many, many discussions about the weather and apparent cycling of weather patterns.  He was originally from southern California where it hardly EVER rained and just the sight of a cloud got him excited about weather. Through observations, it became apparent that even though weather systems moving around the globe were mostly transitory and often chaotic, there was a subtle observation that weather patterns would repeat throughout the year.   In other words, the jet stream would show very similar behaviors on a specific time scale.  This cycle length appeared to vary from year to the next. 

The cycling pattern

It is complicated and I'm not going to try and convince anyone that this cycling pattern does exist during the year.  During the northern hemisphere Fall the jet stream (band of westerly winds aloft) will increase in velocity and traverse from a higher to lower latitude or vice versa.  The jet stream winds occasionally amplify into a north/south fashion which is an unstable position for this wind energy to be in.  At some point the jet stream will "snap" back into place (west to east) and starts a sinusoidal rhythm.   Once this first rhythm begins, it will eventually repeat and then continues to do so until the velocity of the wind decreases during the late northern hemispheric summer months. This cycling pattern of the winds aloft and the behavior is similar from one cycle to the next.  The cycle length can vary considerably from one year to the next though (on the order of 25 to 60 days).  Last year (fall of 2013 though the late summer of 2014) the length was about 57 days, give or take (it's not always exact). 

The  tele-connection cycles and oscillations (MJO, GWO, ENSO, NAO, AO, PDO, AMO) that I mentioned above can enhance or even work against this cycling pattern.  In my opinion, some of these may also help to get the pattern started.  Again, it's complicated.

So, the trick is trying to figure out the cycle length and how these other  tele-connection cycles and oscillations will impact the flow above us.  Unfortunately, this cycle length cannot be computed until the first cycle is completed and starts to repeat.   If it's a long cycle, it may not be until late November before I know.  Ugh.

At this point in time, I can only offer a look into some of the indices or background forcing that may be a contributor in the pattern.

The Arctic Oscillation changes quite a bit during the year.  The chart below is just a forecast from long range computer models and is not the gospel truth.  However, the outlook has been consistent in that the index is forecast to be negative through much of January.  A negative phase of the AO (indices below zero) would support Arctic air intrusions into the U.S.

The North Atlantic Oscillation is forecast (again by long range models that may not be entirely accurate) to be near normal to slightly below.  A negative phase of the NAO (indices below zero) indicates a "blocking" Atlantic pattern which would favor systems slowing down and maybe hanging around a bit longer than normal.

The upshot of the two above (AO and NAO) is that IF the guidance is close to being correct, there could be the potential for several Arctic intrusions that would last more than a few days.

The Madden Julian Oscillation (MJO) has not been robust yet, but could be a player in the weather later this winter.  Again, you can Google any of these indices to get a better understanding.  The MJO is a 30 to 45 day pattern oscillation that originates in the western Pacific near the Indian Ocean or Maritime Continents.

There has been much talk about an El Nino developing this fall and winter and some talk of it being exceedingly strong.  A strong El Nino would definitely impact southern California and east across the southern tier states.  I think this is a basis for the CPC forecast.  However, an El Nino has NOT formed yet and is struggling to get going.  Everyone should root for one as this would help alleviate the extremely bad drought that is on-going across California.  The chart below shows the Southern Oscillation Index (SOI) which is a measure of the pressure differences between Tahiti and Darwin, Australia.  A significantly negative value for an extended period indicates El Nino conditions.  

Looking at the Sea Surface Temperature anomalies, the waters across the equatorial Pacific Ocean are slowly warming.

Perhaps more importantly is the above normal temperatures across the north Pacific, tied to the Pacific Decadal Oscillation.   That might be a big player this year if it helps pump up the jet stream into the Arctic or higher latitudes. It will be something to watch.  Also, the temperature profile across the Pacific basis is favorable for the sub-tropical jet stream (winds across the lower latitudes) to become a play maker this winter.  That would provide tropical moisture into the U.S. and help lower surface pressures across the southern plains.  Upshot of this would be an increased chance for above normal precipitation there.  We've already seen a significant occurrence of systems moving into the southwest U.S. since late summer and it'll be interesting to see if that trend continues.

Finally, the Outlook

First I want to show you some solutions from one of the long range forecast models.  Agreed, it is not terribly accurate but when a trend is established there is some useful information that can be gleaned from the models output.  This computer outlook is run 4 times a day, every 6 hours.  From one run to the next there can be big differences, so don't get caught up on the details.  But, what it does show is a significant cooling trend going through November and into early December.  The program that generates this output uses slightly different initial conditions to generate various solutions every time it runs.  This is called an ensemble.   Two runs below that were generated 1 day apart....

The most notable thing is the HUGE range of possibilities!    Even the red line (ensemble mean filtered for intraseasonal conditions) changes from one  run to the next.  But I've been watching this for a while and the trend has definitely been for a colder solution.

I think the big players early on will be an unusually strong extension of the East Asian Jet, a developing sub-tropical jet and the position of semi-permanent low pressure areas over the north Pacific and near Hudson Bay.  I'll be watching carefully to see how these features shift during the next 30 to 60 days.

I feel pretty confident that the balance of October will have normal to above normal temperatures. No widespread freeze is expected!  However, once  we get into November I expect there to be changes.  I would surmise that the first widespread growing season ending freeze will occur that first week of November.  The balance of November will likely be much colder with below normal temperatures on the average.  There should be several opportunities for precipitation (snow too) so that the month should see normal to above normal precipitation.

Getting into December there should be wild swings with Arctic air outbreaks but evened out by dry and "mild" periods.   By the first of December I should have a pretty good feel for the cycle that should be established so I will likely be updating this outlook periodically.

Beyond December and into the spring the only thing I can offer is that I would highly suspect that there will be several high impact winter storms across the high plains, maybe a few more than usual.  A March blizzard seems to be a real possibility this year (greater than climatological chance).

Even though precipitation may be near to above normal across are area, that does not mean snowfall will be above normal.  The reasoning is that some of the storms this year will likely produce freezing rain (or even rain) without producing much snow.   Also keep in mind that EVEN if this map below was close to being correct, not every location in the shaded areas will have the predicted outcome due the variability with individual storms/systems.