Wednesday, November 13, 2013

Sunday Severe PLUS A Look at Christmas


Yes, you read that correctly.  I don't think I have ever blogged about severe weather in November and a Christmas forecast in the same post.  There's always a first time for everything I guess.

Let's start with the most important issue, the severe potential.  Is this unusual?  Absolutely not.  We are in the heart of our secondary severe weather season.  I discussed yesterday on the blog about the potential this weekend.  With a latest information I have analyzed today (Wednesday), I think the potential has increased some.  The timing of this is still very much in question as there are some disagreements.  We want this to develop at night, when less instability exists.  However, there's some potential for all this to happen with readings well into the 70s and plentiful moisture from the Gulf of Mexico... NOT GOOD.  It's only Wednesday and we're discussing something on the table for next Sunday and Sunday night so there's bound to be changes. Oh, that Christmas thing, I'll have more about that at the bottom of this post.  Once again, I will use maps generated by weatherbell.com.  Great site!

This is the Wednesday morning run of the GFS valid this Sunday at noon.  You can barely see it, but at the top of the chart is a surface low pressure area with a cold front extending south into SE KS and western OK.  All those black lines are isobars, lines of equal barometric pressure.  We have a south to southwest flow into that low up north.  What are those colors?  That's known as CAPE (CONVECTIVE AVAILABLE POTENTIAL ENERGY).  This is the instability needed for thunderstorms.  For this time of the year, it's definitely high enough to cause concern.  Once you get those greens and yellows to show up on the map, you really need to watch the situation, especially when you have a lifting mechanism and we do here.... the cold front along with upper level energy.
This is valid at 6PM Sunday.  The CAPE (instability) is still substantial.  However, at this point, the severe threat is ending from west to east.  Also, due to the sun going down at this point, all instability levels will be on the decrease.  So according to the GFS, the time period is Sunday afternoon and early evening.  That can still change though.
Here's the GFS temperature forecast at noon Sunday.  Well into the 60s and 70s.
And here's the warmth at 6PM.  You can already see the affects of the next batch of cold air pushing in behind the front.  It's getting colder in OK and KS.
At noon Sunday, dewpoints are well past the threshold for severe weather chances.  The Gulf of Mexico is wide open for business and you will feel the humidity.  The question I have right now?  How much cloud cover and just how much instability will be realized?
The Storm Prediction Center has highlighted almost all of Arkansas for the potential for severe weather.  This is not a "risk" area, but it's an area of concern.
HO, HO, HO.    Now onto Christmas.  TAKE THIS WITH A GRAIN OF SALT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  Did I make my point? LOL.  I have been watching a particular climate model off of weatherbell.com.  It has been fairly consistent showing below average temperatures around the days just before Christmas and after.  Average is 50 and 32.  What about precipitation?  WAYYYYYYYYYY TOO EARLY!  So again, take it with a grain of salt.  It could be cooler than average, we'll see.

1 comment:

Randy Myers said...

You forecasted white Christmas 2 weeks last year before Christmas and you ended up right and all year I bragged how well you did... :)

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