Tuesday, May 07, 2019

It IS going to rain. But, how much?

Several days ago, I was talking about how we could see 4-6" of rainfall, Wednesday through Saturday. The data started to back off of that projection, but now some data is suggesting that we COULD see that much, but only in our southern counties. Before we dive into the data, here are the bullet points:

  • It is going to rain and it will negatively impact the agriculture community.
  • Some people will get more than others.
  • There is a chance of severe storms.
  • The greatest threat for severe weather now appears to be Wednesday evening and night. MAybe Thursday, if the atmosphere recovers.
  • We get a little break on Friday.
So, let's dive into some data. First, I heavily forecast using the Euro model. It's typically more stable and has a good history of being accurate. Here's how much rain it gives us through Saturday:
Generally speaking, it is giving most of Region 8 a good 1-3" area-wide, with some 3-6" in our southern counties. It's hard to argue with this model, given this setup. If this verified, parts of Poinsett and Cross counties would get the worst of it.

Another model that you will hear us use, is the GFS model. The GFS model also has our southern counties getting it the worst, but it has a SHARP gradient drop off as you move into our other counties of Region 8. It also has the heaviest rain from I40 southward: 
And now to one of our short range models. The NAM shows a solid 1-3":
Here's the deal. Some people are going to get over 4" of rainfall. We are going to have to watch how this storm evolves and unfolds. Pinpointing the exact location of the worst impact is almost impossible and really isn't going to to change anyone's preparation, at this point. We are going to be watching it closely, so stay tuned. I probably won't blog much more on this storm, so follow me on Twitter at @ryanvaughan and look for video updates on the Region 8 Weather App.


Saturday, April 06, 2019

Storms Increase Tonight

First, the daytime hours today will be warm and dry. Get outside and enjoy it! Tonight, the atmosphere becomes more unstable and storms move into Region 8. The main threat tonight will be hail. As always, we can not rule out a tornado. 

First, here's a look at the energy needed for the storms or CAPE. At first, it's all south of Region 8:
But, through the evening hours, the atmosphere becomes more unstable:
During this transition, we will have thunderstorms moving across Region 8. This is what radar could look like around 11:00 PM tonight. Once again, the main threat is hail, but I'm not going to rule out a tornado, so keep your app alerts ON and your location services ON.
Tomorrow, the atmosphere stays unstable for most of the day, but it won't storm all day.. 
 It's one of those days when the storms won't last all day, but what DOES form, could be severe. This is what radar could look like at 11AM:

Stay tuned for APP UPDATES through the day.


Friday, February 22, 2019

Severe Threat Shifting SE, But Still Needs Watching

This map shows some good news for parts of Region 8, but we are not letting our guard down and not changing our plans on coverage. I am still highly concerned for areas around Wynne to as far north as Blytheville.

Let's dive right into some maps. First, we will hear storms through the overnight, but they will have more BARK than BITE. This means... they will mainly just be loud. By 11AM, the atmosphere is prime for severe storms with damaging winds and possibly tornadoes. Just because the greatest threat is shifting SE, DO NOT LET YOUR GUARD DOWN ANYWHERE IN REGION 8:
In addition to the storms, I'm worried about the wind outside of the storms. We call this "gradient winds" because they are the winds that are dependent on the gradient between high and low pressure. During the daytime hours, they will gust over 40 mph from the south...
As go into the overnight, the winds gust from the NW over 40 mph:
With SATURATED ground, this will be like wiggling loose teeth on trees! I would not be surprised to have trees down and power outages from the winds alone. We will also be watching for that threat.

Stay tuned!

Wednesday, February 20, 2019

Severe Weather, Saturday February 23rd.

We've had another active 24 hours, with many locations picking up another 2-3" of rainfall. This moved Jonesboro to the 5th wettest February on record. Now, it's time to focus on Saturday. The models are not in full agreement, but they are in enough of agreement to be concerned about severe weather Saturday afternoon. The details will be come more clear in the next few days. Make sure you have our Region 8 weather app for video updates. Here are my thoughts about Saturday, as of today:

  • All modes of severe weather are possible: Wind, hail, and even tornadoes.
  • Straight-line wind damage is the main threat.
  • Timing appears to be Saturday afternoon. It's too early to get any more precise. 
  • Additional 1.00-1.50" of rainfall.
  • We are still keeping it a LOW risk of severe weather for now, but may upgrade that to a Medium risk. I do not expect us to upgrade to high or extreme. 
We are going to have all hands on deck on Saturday. Bryan and I will likely be in studio in case we have to break into regular programming, Zach will be out in the Central Nissan StormTRACKER. 

Let's dig into some maps. This appears to be a very dynamic system. The winds within this storm will be strong and will change with height. This first map shows is the winds about 5,000' up. I get concerned when the winds are over 35-40 kts. This map shows the winds at 5,000' will be about 65 kts on Saturday afternoon. 

In addition to the wind speed, they will be changing with height. This map shows the change in wind direction with height. Notice that the speed and direction change with height:
The air will be marginally unstable, but impressive for February:

We'll keep an eye on it.

Tuesday, January 22, 2019

Rain Tonight. What about Snow?

I think we are all a little uneasy about a forecast that calls for rain to end as snow after last Saturday. On Saturday, we expected MINOR accumulations (until Friday night and Saturday morning), but the colder air plunged in quickly and we saw a few inches of snow in parts of Region 8. I didn't really pick up on that trend until Saturday morning, just a few hours before it got crazy. A little later than I wanted.... but, I'm glad that we were a little above freezing or we would still have covered roads.

With that said, we once again find ourselves in  situation where the rain will end as snow. As you can imagine, I'm a little hesitant to say that there "will not be much accumulation", BUT I'm going to do it anyway. Tomorrow morning does not look like a huge problem. Here are my thoughts right now:

  • Most of the daytime hours will be dry and windy.
  • Rain increases tonight.
  • A squall line moves through between 2:00-4:00 AM.
  • Severe weather threat is very low, but the winds could get gusty.
  • 0.75-1.00" of RAINFALL expected.
  • Briefly ends as snow around mid morning.
So, let's dive into some data. All of the models show a wet night across Region 8. These maps show what radar could look like at 3AM and you can see the heavier squall line that could have some thunder overnight:

We don't need any more rainfall, but it's coming. Most data is showing 0.75-1.00" of rainfall. Here are the model runs in graph form:
This is what it looks like on a map:

Lastly, some of the data still shows the rain ending as snow, but ALL DATA shows little to no accumulation:

So, get ready for a soggy night and a wet drive to work and school on Wednesday morning. Don't panic if you see snowflakes.