Sunday, January 27, 2013

Tuesday Trouble Update


11AM Sunday Update.  A look back at the big snow 13 years ago on "Ninja's Corner".  Click on the logo to the right.

It's going to be one of those weeks here in Arkansas that will have everyone talking about the weather.  As I have been telling you here on the blog, we will challenge record highs Monday and Tuesday as temperatures soar to near 70 degrees.  We'll have a round of rain and storms Tuesday and I'm still not throwing in the towel for at least some sort of wintry weather.  In other words, we'll have 2 seasons within a short period of time: spring and winter.

When it comes to the spring like weather Tuesday, I have two BIG concerns and both are amplified as a result of the Christmas Day snowstorm.  The Gulf of Mexico will pump a large supply of moisture northward Monday and Tuesday.  Please look at the previous blog post for more about that.  This will enhance the threat for heavy rain.  In my neighborhood and in many others across central Arkansas, huge piles of debris remain in storm drains.  With heavy rainfall expected, street flooding COULD become an issue.

Also, this system will have ample amounts of wind energy and one of the main threats with these storms will be gusty winds.  Limbs and entire trees are still dangling on power lines along the side of the roads.  These could easily tip over when the winds are elevated and someone could get hurt or killed if this problem is not fixed.  Also, this COULD increase the number of power outages if high winds do become an issue.  It's really amazing to see we are still feeling the effects of that storm more than a month later.

There are some differences in the models that I will allude to here.  First of all, if you read this blog, you know how bad the NAM has been this winter.  With that said, at some point it's going to be right.  Is it now?  I just don't know.  Last week there were a couple of runs of the Euro which indicated a piece of the storm system hanging back across the southwestern United States.  The model eventually brought it out and created a snowstorm over the mid south.  Since then, the model has taken that possibility out of the equation.  But was it hinting at something?  The NAM shows that piece of energy hanging up, but still coming out with the whole system.  It's not as phased as the other computer models.  This basically means, that it better develops a surface low and grabs cold air on the back side of this system.  The NAM implies very heavy rain with a changeover to some light snow across the northwestern half of the state.  Remember, this is not a forecast, but just a possibility that must be watched.

Another example of huge limbs dangling on power lines.  This is literally just 2-3 feet off Kanis Road.  A wind gust could knock this down on top of a passing car.  Someone could get hurt or even killed.
A clogged storm drain in west Little Rock with debris from the Christmas Day storm.    Any heavy rain will flood roads easily.
Huge piles along the side of the road will not allow water 
 to drain properly. This too is in west Little Rock

The early Sunday morning run of the GFS indicates rainfall amounts around 1-3 inches across much of Arkansas
This is the overnight version of the NAM.  There's a corridor of heavy rain from SW through central into northeast Arkansas.  This shows total rainfall here could be in excess of 4 inches.

HPC's manual progs don't show as much.  They are going with 2'' or more across much of Arkansas.  This would still be enough to cause street flooding issues.
The Storm Prediction Center has outlined all of Arkansas for slight risk of severe weather Tuesday.  The main threat will be wind and maybe some hail.  Isolated tornadoes can't be ruled out, but at this time, that threat is low.  This can still change however.  Instability could be a limiting factor for a more widespread severe weather event.
In Summary, a round of rain and storms will likely move across the state Tuesday and some could be severe.  The main limiting factor for a more widespread event will be low amounts of instability due to the presence of clouds and showers.  However, this can still change depending upon the evolution of the storm.  It's still over the Pacific Ocean and will be better sampled once over land late today and Monday.  That's when we should have a better handle on the situation.  The main threat will be heavy rain and wind.  Once again, we can't rule out isolated tornadoes, but that threat continues to be on the low end.  However, that can still change and we're going to watch it for you.

The other thing to watch as I alluded to above is any frozen precipitation along the back side.  Some of the data suggests that and it's within the realm of possibility.  I'll keep you updated.

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NOAA Winter Guidance