Tuesday, August 26, 2014

Updated August 26, 2014

Click here for the previous post done on the 20th of August.

A few more changes are taking place in the overall weather pattern across the northern Hemisphere.  The most notable has been the "strong" upper systems dropping into the Great Basin area.  The first brought copious and excessive rainfall to Montana over the weekend.  There has been major flooding reported from the rains.  The second upper system had dropped into the same location of the west and was lifting out as of Tuesday afternoon.  The result of this was an anomalous increase in the North American Monsoon (NAM) moisture as indicated on the satellite image below.  You might also notice the very intense hurricane (Marie) in the eastern Pacific with some of the moisture being drawn north by the upper system.


The setup is there to produce widespread rains over the next 5 to 7 days across much of the central Rockies and adjacent plains states, especially along and north of a frontal boundary that should set up across northern Kansas and Nebraska.   Looks like much of the corn belt will be receiving a lot of rain...and cooler temperatures. The following map shows expected precipitation amounts over the next 7 days and is courtesy of the Weather Prediction Center from NOAA:

 Adding these amounts to what has fallen between August 20th and today (26th), there are going to be some areas of Colorado, Nebraska and even parts of Kansas that will be quite wet by the end of the month.  The following map is amounts that have fallen in the past 7 days:

In the previous post (please take the time to read by clicking here) I had mentioned the possibility of a wet September and early October.  The "wet" long range computer model I had discussed continues to have a wet outlook, although not quite to the extreme.  This model is not necessarily that accurate but as I mentioned before the trend has been there for some time.

What about El Nino?  It is still struggling to develop but S L O W L Y seems to be developing.  Remember, for an El Nino (and there are several regions that it develops and "lives"), the numbers need to be strongly negative for at least 3 months.  It is trending that way at least.   More discussion on that in  a later post...

All thoughts are my own and are not intended as an official statement.  Please share the link for this blog...


Wednesday, August 20, 2014

Update - August 20, 2014

Please see the previous post here.

Amazing as it may seem, it appears the atmosphere is already starting to transition out of Summer across the northern Hemisphere!  There is a lot going on right now.  The North American Monsoon (NAM) continues, although farther to the west.  Arizona has been getting pounded lately with heavy rain and flash flooding.  Rains have diminished across Colorado, and for the most part across much of Kansas.  There still have been scattered storms and looking at the map below you can see just where the rains have occurred since August 1st.

The next map shows the percent of normal.

But, even though the NAM continues (albeit farther west) the jet stream winds are increasing across the northern Hemisphere.  This is a little ahead of  schedule.  That could be because of the tropics (land and ocean areas) are continuing to warm while the Arctic, or above 80N is cooler than normal.  Looking at the satellite image from Tuesday there are a couple of interesting features across North America.

There is that "low" again across the Great Lakes.  Seems as if we've seen that quite a few times this summer.  If that repeats again in September....more on that at the end of this post (but don't cheat and skip over the rest of this).  The other feature is the low (L) over California.  This low will eventually lift out into the Rockies and move east or southeast across the northern and central plains late in the weekend and first of next week.  The result will be a cold frontal passage and a dramatic increase in thunderstorms across the plains.  Look at the precipitation prediction through early next Wednesday (provided by the Weather Prediction Center)! That is a lot of rain across the northern plains!

You might also notice the generous precipitation signal for the northwest half of Kansas.  As we get closer I'm sure this area (and amounts) will be refined.  I'm pretty confident that much of northwest Kansas will get quite a bit or rain with lesser confidence into southeast Colorado and the panhandles of OK and TX.

The drought continues!  Yes many areas have seen beneficial and sometimes excessive rainfall this summer (but not everyone).  However, officially much of the high plains is still in a drought.  Why?  Because it takes a long time for a major drought to develop, and it takes a long time to get out of one.  We're with out a doubt moving in the right direction.  But looking at the deficit of precipitation over the past 3 or 4 years there is still a significant one.  The following maps show precipitation at Dodge City since October 1, 2013 (considered a water year) and precipitation since October 1, 2010 (combined water years).  You will be able to see the deficit I'm talking about...

Officially much of the area is still in a drought (but again it's improving)....

So the outlook through the middle part of next week is for an improving chance for precipitation, especially late in the weekend or early next week.  Temperatures should be gradually coming back down after this week.  This current week may be about the "hottest" stretch that will occur for the balance of the summer.  That may not be good news for the late maturing corn, sorghum and acres of northern cotton .  Yes there will be more hot weather but the prospect for a long stretch is very low.  In fact, there is some indication that as September approaches there may be quite a few below normal temperature days.  That leads me back to the statement earlier in this post about that low over the Great Lakes returning.

Let me first state that weather patterns that become established in the fall will generally repeat at various cycle lengths and amplitudes and continue through the winter, into spring and summer and completely diminish by August or early September.  So the pattern that has been in place this year actually started last fall, but is about to "disappear" and re-establish.

If this pattern across the northern Hemisphere can continue and repeat just one more time, then there is a greater than climatological chance of a rather cold airmass invading the U.S. sometime in mid to late September.  That would mean a frost or freeze much earlier than normal, especially across the corn belt and perhaps into Kansas.  It's not out of the question we could have a hard frost or freeze in Kansas around September 25, give or take 3 or 4 days.  However, if that doesn't happen, the new pattern that will be developing will likely set up to be a colder pattern, meaning there could still be an earlier than normal freeze.  More on that in a later blog as I attempt to give an outlook for the fall and winter.

Finally, I want to briefly discuss a long range forecast model that is run 4 times a day.  It's not precise or extremely accurate but it has shown  trends in the weather pattern.   When I have an idea of the weather pattern in my mind and if this model supports my notion, then I tend to look at it a little more closely.  The model run from yesterday (Aug 19) evenings upper air soundings and global current conditions yielded an extremely wet outlook into early October!  It has also been very consistent in showing a wet signal for several days.  I was already leaning for above normal precipitation for the early fall - not that I believe this run completely but it's something to consider.  The graph below shows predicted accumulation of precipitation for Dodge City through early October.  Initial conditions were changed slightly yielding a different outcome providing 5 different solutions or forecasts.  The black line is the average of the five different runs.    Basically the result is record rainfall between now and October 4th.  Do I believe that?  No, not really.  BUT, it does support my thoughts of above normal precipitation.  I guess if somehow the model was completely accurate then there would be major issues of getting fall crops (if they can even mature) out of the fields and get the winter wheat up and growing without getting it washed out of the ground.  The same computer forecast model has shown an outlook of below to much below normal temperatures for the fall.  I tend to agree with that notion also.

I'll update again next week.  

As I mentioned in the last post, if you find this blog useful or helpful please share the link.   Again, these are only my thoughts and NOT an official outlook from the NWS or NOAA.

Tuesday, August 12, 2014

Update - August 12, 2014

The previous post on July 30, 2014 (click here) was discussing the heavy rain event that was progressing across the area. There were a couple of locations that had excessive VERY rainfall.  Once was out in eastern Colorado near Eads where amount of 7.64" was measured!  Another was just northeast of Greensburg that had 5.03 inches!  The following map depicts the total ending on the 30th...

For the month of July there was quite a bit of variance across the area, which is very typical for the warm season where the majority of precipitation falls from thunderstorms.  Thunderstorms produce highly variable precipitation rates, depending on many factors.  The following map is for July....

There were only a couple of days that had "hot" temperatures above 100.  At Dodge City we've only had 2 such days this year.  (I have mentioned several times in previous posts that there probably wouldn't be many 100s this summer and so far that has worked out).  The 15th through the 18th had anomalously cold weather with daytime temperatures staying in the low to mid 60s on two of the days and only in the 70s on the other two.  Did this stretch do anything to growth of the corn and sorghum?  The number of growing degree days will undoubtedly be less than normal for this growing season.  This "cold" also has stretched across much of the corn belt.  It will be interesting to see IF these crops can mature before the first freeze arrives.

For the next week or so the pattern will be characterized by a continued North American Monsoon (NAM) and periodic cold front passages.  The  satellite image from a couple a days ago shows several interesting features.  One is the low and moisture that has finally impacted the Pacific Northwest.  Another feature that has been persistent this summer is the little low associated with the NAM poised to move north into the Great Basin and will be moving into the plains (mostly northern) the last half of this week.  Another feature that REALLY has caught my attention is the system over the Great Lakes and which brought very excessive rain to New England this week along with colder air.  If this feature returns in September then we can expect a very early FREEZE across the corn belt.  Could be a major price mover as we get closer?  I'll keep an eye out for this possibility and post at a later date.  Here is the aforementioned map...

With the recent rains this summer the drought has improved at most locations.  There are still those "unlucky" ones that have missed out on the big rains.  Surely that luck will improve?

I'll be posting my thoughts on the fall and winter later this month.  The well advertised El Nino has NOT developed yet.  But, slowly but surely, it's starting to look like it may be developing.  The latest SOI chart below shows the progress.  Remember the indices need to be strongly negative for about 3 months for an official El Nino event.  It's complicated but El Nino is not the only feature that will calls the shots for later this year and into 2015.  Again, I'll post something on this a little later this month.

If you find this blog useful, please pass the link on.  There doesn't seem to be much traffic right now.  As I posted earlier during the spring, this is NOT an official posting from the NWS.  This is ONLY my thoughts.