Wednesday, October 29, 2014

Halloween Snow, 21 Years Ago

It's been 21 years since kids were Trick or Treating in the snow in Region 8. Snowball fights on Halloween night in Arkansas may be weird, but that's what happened over 20 years ago. When you hear about this night, it's always referred to as the time "it snowed on Halloween", but it was not ACTUALLY Halloween. You see, Halloween fell on a Sunday and many cities in Region 8 chose to trick or treat on the night before. So, the snowfall was actually on October 30th. The above image shows the strong upper-level low that had dipped south to help bring the snowfall. This is Saturday evening's 500mb map.

I decided to dig up some old climate logs to see what was written about this snow event and this is what I found. Here is the Jonesboro log for October of 1993 from Terry Wood. Click image to enlarge:
Notice, Terry logged that we had sleet and snow, with about a half inch of accumulation. Some places had more accumulation than others. Here is the historical log from Pocahontas. They has a nice snowfall, with accumulations of over an inch! Region 8 Weather Watcher, Jason Hampton, said they were having snowball fights in Randolph County as they were Trick or Treating! Click image to enlarge:
Finally, let's check one more location from that day. This climate log came from Doniphan, MO. Notice, over 2" of snow reported! Once again, click image to enlarge:
I hope you enjoyed taking a look back at the "Halloween" snowfall of 21 years ago. This Halloween will not have snow, but it will be cold!

Enjoy the cooler air!

Sunday, October 12, 2014

Severe Weather on Monday, October 13th

Good evening everyone. It's 7:15 PM on Sunday night and I'm in the storm center for Andrew tonight. There still appears to be a threat for severe weather on Monday. Let's break down the bullet points first:

  • School teachers and administrators need to review their severe weather plan in the morning.
  • Parents, schools have a plan in place, so don't worry about your kids at school.
  • 2 rounds are possible. I'm expecting a small round of storms late tonight into daybreak that could be severe. The greatest threat would be hail, but damaging winds and even a tornado can not be ruled out. This will be ahead of the warm front lifting north.
  • 2nd round will be stronger and I'm expecting that to mainly be in the afternoon. More on the timing of this round in a graphic below.
  • Damaging winds will be the main threat, but hail and tornadoes can not be ruled out.
  • The severe weather threat ends by tomorrow evening.
  • Timing is still questionable and one of the most difficult parts of this forecast.
  • Watch Justin in the morning for the latest info.
OK, let's take a look at some data. If you step outside right now, you can probably feel the air becoming more unstable. We look at CAPE or "Convective Available Potential Energy" when forecasting severe storms. The CAPE was zero this morning and the air was very stable. It's becoming more unstable tonight. This is a map showing the CAPE by 1:00 AM. The greens and yellows are the areas with the highest "Potential Energy". This will help the storms that will develop before the sun comes up:

As a result, this is what radar could look like at 2:00 AM. As I mentioned earlier, these storms could have large hail:

Let's fast-forward to the second round. Take a look at the CAPE at 1:00 PM. You can see that we are unstable and you can clearly see the front coming through:
As a result, we should have a very healthy squall-line moving through at 3:00 PM. If this model verifies, dismissal at schools may need to be delayed until the main line moves through. Pay close attention schools:
To summarize, we should see some storms develop before daybreak. The main line will come in later in the day and here is the timing for it. Stay tuned for changes!:

Here are the threats for Monday:
And finally, here is a map that shows where the greatest threats are located. We may make a "high" threat area on this map at some point on Monday:

Now is not the time to panic. We have had much worse weather in the past, but let's all have a plan tomorrow and be safe. 


Tuesday, October 07, 2014

Heavy Rain Possible, Fri-Sun, October 10-12

It's only Tuesday and this could change, but it looks like we could see a heavy rain event on Friday through Sunday. Here are the bullet point right now. Stay tuned for changes:

  • Widespread 2-4" of rain is possible. (On top of what you get before then)
  • Some areas may see over 4".
  • Severe weather will be limited, but possible.
  • Football Friday Night could be wet and sloppy.
  • Saturday morning outdoor activities could be wet and sloppy.
Here are two computer models showing how much rain could fall between now and Sunday. First, the GFS model:
And now... the Euro:
As you can see, the data is in agreement right now of some heavy rain. We are going to continue to track this setup over the next few days. If anything changes, we will update everyone.


Wednesday, October 01, 2014

Wind Chill in the 30s?

It's possible! In the wake of the cold front set to come through, we could be quite cold on Saturday morning. The models continue to trend cooler! Now, we are not covering the plants or anything, but bundle up on Saturday. Take a look at the latest data from the GFS regarding temperatures at 7AM on Saturday. Click image to enlarge:
I'm pretty confident that everyone wakes up with an air temperature in the 40s. West Plains may even be in the 30s! There will also be a little bit of wind. The grey areas show 5-10 mph winds from the west or northwest:
Factor in those cool temperatures and a little bit of wind and there is a CHANCE we have the wind chill in the 30s EARLY on Saturday. If you have plans early in the day, bundle up. By the afternoon, it will be milder with temperatures in the 60s. Here's the GFS on wind chills at 7AM on Saturday:
My family will be at youth football early on Saturday and I'm looking forward to the football weather! If you are going to the A-State game on Saturday, it will get chilly fast after the sun goes down.

Take care,

Severe Weather Update

Like I have done in the past, let's start out with some bullet points:

  • Severe weather is possible late on Thursday into Friday morning.
  • Gusty winds appear to be the main threat.
  • Hail is possible.
  • Tornado threat is low, but still possible. Know your plan in case a warning is issued.
  • Most of the storms will come after sunset. Meaning, most of Thursday will be dry.
Let's talk about timing because a lot of you have football games, practice, the Boyer Mile, lawns to be mowed, swim practice, etc, etc... Remember, these images are model driven and the timing could change.

Around 7PM, a line of storms will be moving into the state, but still west of Region 8. We can not rule out some isolated storms ahead of the main line. If one of these storms impact your outdoor plans, it will not last long. These storms will probably be strong in NW Arkansas, with some severe thunderstorm warnings. We are hoping they weaken as they move East:
Three hours later, around 10PM, the line of storms will be moving into Region 8. If this data does not change, we will be tracking storms at the top of Region 8 News at 10:00. The storms will have likely prompted a watch (either Severe TS or Tornado) and there will probably be a few warnings in the state. Heavy rain and lightning is likely:
By 1AM, the kids and dogs will be climbing in bed with you because of the lightning, but I'm hoping nobody has to be in their Tornado safe spot. Typically with a squall line, the tornado threat is low. It's not impossible to have a tornado, it's just not as likely. Make sure you have a way to get the warnings in case a tornado warning is issued. Here's what the data shows for 1AM:
By 4AM, the storms have crossed the river and they are out of Region 8:
The weekend is looking AWESOME. The weather will be nice for Football Friday Night, tailgating the A-State game, and the game itself. Make some outdoor plans!

Don't forget to follow me on Twitter at @ryanvaughan ... I have frequent updates there.


Tuesday, September 30, 2014

Severe Weather Possible on Thursday

It has been awhile since we have had severe weather. While this does not appear to be a major severe weather outbreak, we need everyone prepared. Make sure your weather radios are on Thursday and make sure your family knows what to do in case a tornado warning is issued for your area.
Let's dig into the details. There is a chance of severe weather on Thursday. Right now, we are thinking the greatest threat will be from central Missouri to Western Arkansas to NE Texas. That's where we are highlighting a "Medium" risk of severe for Thursday PM. The areas in yellow have a low risk of severe weather, but that may change as we move closer to Thursday.

The Storm Prediction Center has outlined most of the area in a "slight" risk for severe weather. As I mentioned earlier this year, at KAIT, we are trying to convey the risks a little better with a "Low, Medium, High, and Extreme" risk. We feel it is easier to understand than the categories from the SPC and it allows us to adjust where we think the greatest risks will be located. The SPC does a great job and we will still use them for guidance, but we are trying to make the threats easier to understand for everyone.

With that said, let's take a look at what radar may look like on Thursday afternoon:
By late in the afternoon, as you see in the above image, we should have showers and storms from SW Missouri, through SE Oklahoma, into Texas. Here in Region 8, we expect some sunshine and very warm temperatures that will be making our atmosphere more unstable. By sunset, we will probably see some storms developing ahead of the main line in Region 8.
In above image, you can see the storms trying to develop ahead of the main batch of storms. These storms could be severe. Hail is possible and even a small chance of a tornado. We will be tracking the storms closely. Notice, the storms in western Arkansas are stronger at this point, with heavy rain.
Between 10pm-2am, the main line of storms will move through Region 8. As the line passes through, we expect:

  • Heavy rain
  • Lots of lightning
  • Gusty Winds
  • A chance of hail
  • Isolated tornado possible

Stay tuned,