Tuesday, September 30, 2014

Update - September 30, 2014

In the last post (click here) I briefly discussed the substantial precipitation that was expected across the west and for some precipitation for the plains.  I also mentioned the possibility of severe weather.  Those that may have caught the news or surfed the net, there was very severe hail in the Denver area on Monday and there were severe weather reports all the way down into southern New Mexico.  

Today (Tuesday and Wednesday) there is a risk of more severe weather across the central and southern plains.  

Rainfall from the first system that ejected into the plains was very robust across northern Colorado, western Nebraska and into the northern plains.  In the local area there was also generous rainfall across about half of the area.  The map below shows the 24 hour precipitation that ended this Tuesday morning.

There will be a chance for additional rainfall through Thursday.  The best chance for the high plains will be Wednesday night and Thursday as another developing upper system moves out of the Rockies.  As of Tuesday afternoon this system (denoted by the red X on the map below) was moving into the Great Basin.  The first storm (denoted by the red L) will drive a cold front into Kansas and then this front will interact or act as a focus for rainfall as the Great Basin system moves out.  Rainfall will likely be heaviest across eastern Kansas but much of central High Plains should receive at least some rainfall by the end of the week.

This next map shows the possible precipitation amounts through early next Tuesday.

As the second Great Basin system moves out there will be some chilly air drop south behind it.  I would not be surprised to see low temperatures fall into the mid or upper 30s as far south as Dodge City and Elkhart by Saturday morning.  Freezing temperatures will be likely across the northern plains.

In the context of freezing temperatures, there has been a "killing" freeze across areas that normally see one by this time of year.  BTW, a "killing" freeze is one where temperatures fall to at least 28 degrees for several hours.  The following map shows where a killing freeze has already occurred.

...and this map shows the dates of the average first 28 degrees or colder of the fall...

For much of Kansas the first episode of 28 degrees or colder can vary considerably from year-to-year but the median date runs from October 11-20 across the northwest to November 1-10 across the south central and southeast.  Remember, this is for a "killing" freeze and not frost or light freeze.  

Looking ahead, I'm starting to see SOME indications of an active period from around October 11 - 17 and if this comes to pass I would bet there will be some pretty cold weather following in the wake of that period.  Pretty cold?  A killing freeze.  This scenario is just a possibility since right now there is NO computer model even remotely hinting that this could occur.   In addition to the cold, there SHOULD be an opportunity or two for more precipitation.  There will also be a chance or two for rain during the second week of October.

As we get deeper into October the weather may become increasingly active but confidence at this point is rather low.  I soon as I see a pattern start to evolve, I will put out the seasonal outlook.  Early indications based on some forcing locations across the northern hemisphere is for at least "normal" precipitation for the fall and winter across much of the area.  I'm tilting the odds in favor of a wetter verse dryer pattern. Temperatures may see some wild swings but the average into the winter should favor normal to below.

More later on the outlook - I've got to gather more data!

Remember this is not an official discussion - it's my thoughts only.  

Thursday, September 25, 2014

Update - September 25, 2014

Due to being on travel and attending workshops and meetings this is a late update....

The big news during the past 7 to 10 days is what happened to the remnants of what was once Hurricane Odile that moved up the gulf of California and heavily damaged one of the Mexican resorts.   If you go back an look at the blog post I did on the 15th by clicking here you will see the discussion about what Odile might do.  At the time there was a "chance" that the remnants would curve east/northeast and head towards the central plains, including Oklahoma and Kansas.  There were concerns about the amount of precipitation that might occur.  As it turns out there was SO much convection (thunderstorms) that the latent heat release from those storms (and from interruptions from the mountains of New Mexico) that the storm turned more east and southeast!   It is probably a good thing too as rainfall from the remnants was EXTREMELY robust and there was a lot of flooding issues.   Look at the map of precipitation the past 7 days where there was over 20 inches across southeast New Mexico and west Texas!  WOW!

Across Kansas and adjacent states, the rainfall was more spotty.  Although, there were areas that did receive quite a bit of rain and most of this occurred late on the 23rd.

The rainfall across the southwest U.S. and into Kansas has continued to make a dent in the long term drought or in some cases completely alleviate it.

The Weather Prediction Branch (WPC) of the National Weather Service is indicating some substantial rains during the next 7 days across much of the western U.S.   WPC doesn't have a lot of precipitation across the regional area, but at least some.  There should be another front arrive in Kansas late in the weekend or first of next week so there should be at least a chance.  We'll have to watch that system carefully as the second season of severe weather will be ramping up and it's not out of the question that severe weather could occur during the first part of the week.  It's just too early to give much detail. 

The latter part of the week should see a significant cool down and  even freezing temperatures across the northern plains.  I'll address that in a post next week.  Then, into October some of the long range models are still indicating ample precipitation.  The "wet" computer model I've posted about lately is still indicating above normal precipitation (notice I said precipitation and not rain? hint hint).

With a bit more time on my hands I'll attempt the seasonal outlook in a blog by October 3.

Please feel free to share this blog.

Sunday, September 14, 2014

Update - Monday, September 15, 2014

As predicted the cold shot last week was pretty substantial.  Across much of the midwest and plains states there were NUMEROUS record cold temperatures observed late last week.  In Kansas there were several sites that saw temperatures below freezing.  The coldest I saw in Kansas at an official NWS location was 31 degrees at Ness City.  It got down to 30 at a mesonet site near Jetmore!  High temperatures Friday were only in the 40s and 50s and across Wyoming and the western Dakota's there was heavy snow with as much as 10 inches reported!  I've talked briefly about this in previous posts but I "think" the cold was the result of the pattern that started last fall and was waning during the late summer.  In the same token the pattern that delivered the cold may be tied to forcing that has been in place across the northern Pacific that helped produce the long term pattern in the first place.  Hint - the forcing remains (and is likely to persist this winter).  I will do a fall/winter outlook later this month when I have more time to devote to the outlook.  Look for that outlook around the 24th-26th.

Rainfall this past week was most widespread across Colorado, the northern half of Kansas and into Missouri.  Since the 1st of September there have been quite a few areas that received some beneficial rains, especially across some of the driest areas of the drought. The following map shows the rainfall that has fallen:

The U.S. Drought Monitor continues to show improvement across the central and southern plains.

Back to the cold.  I'm guessing that the stretch of cold has set back the maturing of the sorghum?  How about the beans and corn?  As I mentioned in earlier posts, September should end up below normal on temperatures.  There will still be some very warm (and windy days) but those days will become less numerous.  As of this writing another significant cold front had moved across much of the area with temperatures only in the 50s.

The next big weather maker will likely be the remnants of Hurricane Odile that was moving into the Gulf of California Monday.  This Monday afternoons satellite image shows the massive amount of moisture associated with the hurricane. 

The remnants will help support very heavy rains across the southwest U.S. which has been hard hit this past month.  Currently it appears that the remnants will then move east into the central plains by the weekend and should enhance rainfall chances.

The Weather Prediction Center generated a map this afternoon which showed the possible rainfall amounts during the next 7 days.  The story here is additional significant rains across the drought stricken areas of the plains and even central and northern Texas!

In earlier posts I mentioned the possibility of September being above normal on rainfall.  If the remnants of the hurricane do in fact track as depicted, then yes the month will end up above normal.   One of the computer models (that really is not that accurate but depicts trends) continues to indicate a wet fall.

The map above shows just several ensemble (computer runs with slightly different initial conditions) iterations and most are wet into late October.

What about El Nino?  It is S L O W L Y developing or so it would appear.  Temperatures off the southern part of Australia (southern hemisphere) continue to cool and is increasing the ocean thermal circulations which is helping this warm event (El Nino) develop.

NOTE:  A prolonged period of negative values indicates an El Nino. 

I'll hopefully find some time to post again in a week.  Remember to share the link for this blog (if you find it useful anyway).   The link is:  swkswx.blogspot.com

Thursday, September 4, 2014

Update - September 4, 2014

Did you notice the change to the blog page name?  This is no longer a "Spring and Summer Outlook" as I've been summarizing what has happened, what is occurring and what is in store.  Please share the link swkswx.blogspot.com.  It does take time to put this together and I'm not entirely sure it's worth my time.  The thoughts are mine and not thoughts of my employer.  If you want "official" outlooks, go to the Climate Prediction Center

Also, please visit the previous post if you have not already done so by clicking here.

I'll start this post by showing the precipitation that fell during the previous 7 days (actually from 8/27 through 9/2).

As has been typical for a while, some areas got excessive rainfall while others missed out on getting good rains.

An update to the current drought...

Looking at the precipitation deficit/surplus at the Dodge City airport...we are doing pretty good for this Wateryear (2014 which started Oct 1, 2013).  But the longer term going back to October 1, 2010 is not as rosy but continues to improve.

The satellite image from 9/3 shows several interesting and big "play makers".

First there is that low up across western Montana.  The associated jet stream is taking quite a dip into the northwest part of the country.  This will ultimately deliver some rather chilly air into the Conus, including southwest Kansas.  Low temperatures this week will fall well into the 40s across the northern plains and even well into the 50s across Kansas.  This will further delay the maturing sorghum and corn.  This HAS to be of concern, right?

The other features that will impact Kansas is the X across Mexico (depicted in the above map) which will help deliver energy and moisture in the southwest U.S. and even into the panhandles of Texas and Oklahoma, which a glancing blow to southwest Kansas.  The other will be remnants of the hurricane  moving towards extreme southern California.  The result will be copious amounts of rainfall across the southwest deserts and into Texas and Oklahoma and eventually across the corn belt.  The following map is the 7 day estimate of potential rainfall courtesy of the Weather Prediction Center.
I will be doing a fall and winter outlook soon, at least by September 23-24.  In the meantime, there is still NO El Nino, but it is steadily looking like one will develop late this fall and winter.  That would have at least a bit of an impact on sensible weather.  More later....

The following map shows the Southern Oscillation Index - the trend strongly in the negative for an extended period indicates an El Nino.