Tuesday, September 30, 2014

Clash Of The Air Masses Thursday

You may remember last Thursday my post about the active weather on the horizon and the possibility for at least some severe weather this Thursday.  Since our weather has not been active lately, I thought it was important to start raising awareness.  I know many are probably not in the mode of thinking about severe weather at this time, but it's a reality as we head into October and especially November and December.

Remember the winter forecast post with meteorologist Joe Bastardi's prediction?  He says this winter will be similar to 2002/2003 and 2009/2010.  Each of those falls brought an active severe weather season.  There have been cases when the fall is actually more active than spring.  If you take the Mayflower/Vilonia tornado out of the equation (and I know we all wish we could), last spring would have gone down as one of the quietest severe weather seasons in a long time!

It's really tough to go from warm/humid to cool/dry without an eruption of thunderstorms.  At this time, we're expecting storms to sweep across the state Thursday afternoon and evening.  The main threats will be wind and hail.  The tornado threat will not be high, but it will need to be watched.  The other threat is heavy rainfall.  We could actually use some!  Amounts could easily exceed 1 inch in spots.

This is a very fast moving system so it will out of here early Friday morning.

Surface weather map at 7AM Thursday.  The front is still off to the west.  This will allow instability to develop ahead of it during the heating of the day.
The GFS indicates significant instability Thursday afternoon across much of the state, especially the west and southwest.
Simulated radar from the NAM indicates a line of storms around 7PM moving into central Arkansas. THIS WILL CHANGE. THE TIMING AND STORM EVOLUTION CAN STILL BE DIFFERENT AS WE'RE  A COUPLE DAYS OUT.
We need a little rain!  Amounts will be highest across the west with 1-2 inches possible.
Here's some good news.  Look at these lows Saturday morning from the latest GFS (Tuesday AM).  That's right!  Upper 40s!!!!!!!
The SPC has placed all of Arkansas in a slight risk for severe weather Thursday.

Sunday, September 28, 2014

Much Cooler Air Not Too Far Away

It kinda feels like this September has been warm, but the average monthly temperature is right at average.  However, with a couple more days to go and temperatures well into the 80s, we'll likely end September slightly above average.  This will be the first time that has happened in a year.  We are on a streak of 2 weeks with 80 degree plus temperatures and that will all come to an end later this week.

The time period to watch is late Thursday.  A quick moving cold front will bring rain and thunderstorms.  Strong and even severe thunderstorms will be possible.  As of Sunday, I have slight chance for early morning showers in the forecast Friday, but I think it's very possible all of Friday will be dry.  It's too early to make a call on that.  Friday will feature northerly winds and much cooler air and that will take us into Race For the Cure!  There are signs however, this cool down will not last long.   It's in and out.  Readings may pop above average by the beginning of the following week.  Here's the newest data so far from weatherbell.com

Remember, this is still several days out and specifics can still change.

I'm going to use the European model for this blog post.  This shows you total precipitation amounts between 1PM and 7PM Thursday.  The timing of all this is still in question.

The Euro total rainfall amounts shows some areas receiving heavy thunderstorm rains and other locations not.  Some could see as little as .1'' and some as high as 1-2''.  Where this all sets up is still impossible to pinpoint this far out.  This is just one model run of many.

1PM Thursday temperatures really shows you the effects of rain and cooler air.  Readings in the low to mid 70s north to upper 80s southeast.

7AM temperatures Saturday should be in the 40s and 50s across the state.

Look for highs only in the 70s Saturday according to the Sunday AM run of the Euro.

Thursday, September 25, 2014

Active Weather On The Horizon

Let me first begin by saying this next weather event is a week away and there will be changes as to how this plays out.  However, I want to raise awareness since there appears to be at least some risk for some strong thunderstorm activity.  The Storm Prediction Center even mentioned the risk in their 4-8 day outlook discussion this Thursday morning.  Remember, we're going into our secondary severe weather season as we head into October.  I really want to make it clear, it's very early so please keep checking back and I'll let you know how this should play out as we get closer.  I hope it just turns into an area of rain and moves across the state.

The following maps are from weatherbell.com

This is the GFS next Thursday at 1PM.  You can clearly see the front off to the west and there will be waves of low pressure riding along that boundary as it pushes east.  Increasing warmth and moisture will produce elevated instability values.
Look at the warm air ahead of the front at that time.  Temperatures will be in the 80s and dewpoint values could be in the 60s and even 70s!
By late Thursday, you can see the GFS is picking up on areas where rain and thunderstorms may occur.

In summary, stay tuned.  I hope it doesn't result in severe weather, but when you see a set up like this, you gotta keep and eye on it.   It's still wayyyyyyy too early to get specific.