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HomeHomeWildflower Seas...Wildflower Seas...TexasTexasHouston, we have slight problem in the El Niño Jet Stream!Houston, we have slight problem in the El Niño Jet Stream!
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2/13/2016 3:01 PM
 

“Houston, we have slight problem in the El Niño Jet Stream!”

You might have noticed that the rainfall for the past 40 days has been a bit below what we would expect during a strong El Niño winter.  Well, the blame probably lies with the pesky “Polar Vortex” that has gone on a wobbly trip down from the Arctic Circle into the northeastern parts of the United States.  This “wobble” in the jet stream brought the recent record low temperatures and snow to the Northeastern seaboard, but pretty much shut down the cooler and wet subtropical flow for Texas. 

The typical jet stream pattern during an El Niño winter should put the subtropical jet moving west to east across the southern part of the US. This brings impulses of cooler and wetter weather to Texas. Winter storms also originating out of the Pacific Northwest bring rain and storms to much of the West Coast.  Cut-off low centers are sometimes split off from the main system and get caught up in the subtropical jet stream which then can bring heavy rainfall to Texas. 

The strong arctic jet stream during a strong El Niño will usually stay bound up in a tight pattern around the Arctic Circle.  This shuts off the colder and snowier weather pattern for the Northeast, but allows the subtropical jet stream to move across the southern part of the United States across Texas.  This pattern is what we would expect during a strong El Niño winter.

El Nino Jet Stream: http://www.srh.noaa.gov/jetstream/tropics/enso_impacts.htm

However, as NOAA pointed out in its 2015-2016 forecast:

“Finally, did you notice how two of the years featured widespread below average temperatures, and that one of the years recorded predominantly above average snowfall? This is a reminder that we can't put all our eggs in one basket - there are other climate factors to consider besides El Niño that have the potential to drastically impact our winter and derail the outlook.

One such example is the Arctic Oscillation (AO). In its negative phase, the polar low pressure system, better known as the Polar Vortex, is weaker which allows Arctic air to push further south. Think of it as a spinning top - the slower it spins the more it wobbles. In this case, the cold air "wobbles" futher(sic) south. The problem is, this is very difficult to predict and it can change on a weekly basis” - http://www.weather.gov/abr/2015-2016W...ocalinformation

 Polar Vortex Wobble & El Niño

So during the past 40 days the Polar Vortex has been wobbling southward and pushing the subtropical jet stream farther south than it should be during a strong El Niño.  We are actually experiencing more of what a La Niña jet stream brings than a strong El Niño.  Why is this happening? Well the current thinking is that due to warming in the arctic circle this is slowing down the polar vortex and like a spinning top that wobbles when it slows down so is the Polar Vortex. 

What does this mean for the 2016 Wildflower Show?

The good news is that we had above normal rainfall for the critical fall months for seedling germination and enough rainfall during the November and December time frame to sustain existing seedlings that germinated.  Also due to the series of heavy rain events since May 2015, the rivers and creeks are still running higher which should also mean that ground water levels are still relatively high.  I have received several recent reports that there is good coverage of bluebonnet rosettes in several different locations in the Hill Country. While this does not mean all of the areas are necessarily the same, it is a hopeful sign. 

As of 2/13/2016, the 30 and 60 day Departures from Normal Rainfall maps show most of Texas running one to two inches below normal rainfall.  Given the positive recent reports I have received from the field; I do not think we are in real danger of losing a good spring season yet – emphasis on the word yet! We experienced something similar to this last year during the month of February, but recovered well during the month of March.  Nighttime temperatures have been running below 50F which means the plants are still in their “winter slumber” and not yet needing lots of rain to bush up. 

All that said, it is important to remember that climate and weather are still well beyond our reach to accurately forecast 30 days out.  Should the polar vortex pattern extend well into March and shut down our chances for good rainfall coverage that would likely be a very negative blow to a good spring wildflower season.  If you are planning a trip to Texas just for the spring wildflower show this year and coming a long distance just for that event, then you might want to have an alternate plan in the works.  For us who live in Texas or those who have some flexibility in their schedules stay tuned.  Even in the worst years, I have seen some good spots here and there.  In 2009, there were large fields of bluebonnets and paintbrush in White Hall and Ennis, Texas areas, but virtually nothing in the Hill Country. If the polar vortex goes back home to the Arctic Circle, and the subtropical jet stream kicks in to bring substantial rainfall back across Texas, then “Game On!”  

 
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HomeHomeWildflower Seas...Wildflower Seas...TexasTexasHouston, we have slight problem in the El Niño Jet Stream!Houston, we have slight problem in the El Niño Jet Stream!