Tuesday, March 13, 2018

Why Freeze Watches and Warnings Are Confusing...

In late winter and early spring, we occasionally have freeze watches and warnings issued for Region 8. They are issued when freezing temperatures are expected after the start of the growing season. In late autumn and early winter, they are issued for the first few freezes of the season. Here's the problem: We have 4 National Weather Service offices that cover the counties in Region 8. Each one has different criteria for a "Freeze Warning", so on a night like tonight, the freeze warning map looks like this:
As you can see, the NWS in Memphis has issued a Freeze Warning for about 1/3 of Region 8. the NWS in Paducah, Springfield, and Little Rock did not issue a Freeze Warning. If I showed the viewers the map above on TV, some people would think they are not going to freeze tonight because their county is not turquoise. In reality, most of Region 8 will be at or below freezing on Wednesday morning.

Therefore, you will not see me showing the map above on TV tonight. My job is to communicate the forecast to you guys in an easy-to-understand format. So, I'll be showing you this map, which shows the counties that will likely have a freeze tonight:
This is not a jab at the National Weather Service. They are doing their job based on the criteria for their respective offices. We just need to do our job to communicate these impacts to viewers.

So, if you have some flowers or other vegetation out already, cover them!

Have a great evening!

Freeze Warnings Criteria:

Paducah NWS: Widespread freeze expected with temps falling to ≤ 32F across the CWA. A killing freeze occurs when temps fall to 30°F or lower for at least 2 consecutive hours. Spring – initiated after coordination with UK Ag Wx Center and County Extension Offices, but no later than April 10. Fall end date – once a widespread killing freeze occurs. Normally not issued after Nov 1, unless it has been an abnormally warm fall and no widespread killing freeze has occurred. Source here

Memphis NWS: Temperatures ≤ 32°F during the growing season, the first freeze in the fall, or when a freeze is expected after vegetation has budded/bloomed in spring. The growing season ends with the first minimum temperature below 28°F. Source here

Little Rock NWS: Issued when temperatures are expected to reach 32°F or colder in the growing season. This product is usually issued during the locally defined growing season, or to highlight the first few freezes of the fall, or unusually late freezes in the spring. This product can also be issued for over a widespread area for when the temperature will remain below 32°F for a prolonged period. Source here

Springfield NWS: Can't find online.

Monday, February 26, 2018

More Rain Coming

More rain is coming to Region 8, but the data is unsure of HOW MUCH. Here are my thoughts about the rain coming in:
  • Clouds increase on Tuesday.
  • Rain STARTS Tuesday evening in spots.
  • Rain off and on for Wednesday.
  • Severe threat is LOW
  • Flood Watch is in effect.
  • Rain moves out Thursday morning.
If we had not had 8-10" of rainfall last week, I would not be sweating the chance of rain too much. However, the rivers are rising and the ground is saturated. Any rain is not needed, at this time. That is why we have a Flood Watch. At this times, it appears that the GFS model is the most consistent. It shows the heaviest rain along and south of I40. I think this is very close to what will happen:
The Euro had the heaviest rain band setting up over the center of Region 8. It's pretty much the only model with this solution and shows the most rainfall for Region 8, with 2-3" in Jonesboro area:
And finally, the RPM shows the lightest rain in Region 8, but a ton of rain south of us:

I like doing these blogs, because it holds us and the model accountable!

Have a great day!

Friday, February 23, 2018

Saturday Severe Threat

Good Friday, everyone. I'm off work today, but I finally got a chance to sit down and look at some data this evening. Here are my thoughts right now regarding severe storms on Saturday:

  • Warm front provides some storms from mid-morning to lunchtime. These could be severe, but not as concerning as the storms later in the day. Don't take them lightly though.
  • The afternoon will be the time when the atmosphere charges itself for evening storms. IF we get any sunshine, that would make us more unstable. That's not good.
  • Right now, we have most of Region 8 under a MEDIUM risk of severe weather.
  • Greatest threat will be high wind from storms. The wind dynamics with this storm are very concerning.
  • Tornadoes are possible, especially in storms ahead of the main line in the evening.
  • I'm worried about the wet soil being very loose and trees uprooting easily.
  • All threats should end by midnight, tomorrow night
Here's what radar could look like at lunchtime. Don't take the storms along the warm front for granted, but the greater severe weather threat will be later in the day.:
By mid afternoon, the atmosphere will be more unstable. Sunshine would be bad, but some showers could make us a little more stable. Regardless, the wind profiles from the ground-aloft will support severe storms. Here's how radar could look:
The evening is the most concerning to me. We will have to watch for tornadic storms ahead of the main line and we will have to watch for high winds along the line. Even a quick spin-up tornado is possible along the line. Winds about 5,000' above our head will be blowing about 80 mph. Any heavier storm could transport that wind energy to the ground. That's not good...
We will be providing updates on the Region 8 weather app. Make sure you have your notifications turned on and make sure the "Follow me" feature is on if you are traveling across Region 8 tomorrow! All of that can be found in settings!

Have a good weekend and stay weather aware,


Let me throw a few numbers at you:

  • So far, it's the SECOND wettest February on record in Jonesboro with 10.70", as of 8:00 am on 2/23/18.
  • We are only 0.72" away from having the WETTEST February on record. If that does not happen today, it will likely happen tomorrow.
  • Yesterday was the wettest February 22nd on record with 2.61".
  • I've had 7.4" of rainfall at my house in Paragould, just this week... and it is still raining.
As you probably knew without reading this, we have had a VERY wet week. We are expecting severe storms Saturday afternoon and evening. With such a wet ground, I'm afraid we are going to see uprooted trees near stronger storms. Stay weather aware tomorrow.

Here are the Top 10 wettest February prior to this month:


Tuesday, February 20, 2018

Rainy Pattern Begins: Round 1

As we have talked about for several days, a rainy pattern starts today. I'm going to ONLY talk about this first round of rainfall in this post. There are several maps floating around showing the 7 day rainfall totals. While those maps have impressive numbers, we need to take each round separately so that we don't start building arks! Here are my thoughts as of right now regarding the rain tonight and tomorrow, Round 1:
  • Rain has already started in some parts of Region 8.
  • It will likely rain ALL DAY on Wednesday.
  • On average, 2-3" of rain is likely across all of Region 8 before Thursday.
  • The precipitation RATES will not be that high, so "flash" flooding is not likely. Flooding is possible.
  • I would be shocked to see anyone get more than 0.50" in a 1 hour period.
  • This is a prolonged rain event. It will not all come at once.
  • We get a little break on Thursday (Scattered Stuff) with Round 2 coming Friday.
So, let's dig into the data. As I mentioned, while rainfall looks impressive, it does not look like the rain intensity will stay high through the entire event. Sure, we may have some brief downpours, but most of the rain is going to be light to moderate. I do not anticipate anyone seeing more than 0.50" in a 1 hour period at any given time. If so, it should be isolated. Models are in general agreement for Round 1, with most showing 2-3" of rain. There are some model runs showing less than 2" in spots AND there are some model run showing more than 4" in spots. These would be extremes. Average is 2-3". Here are four models showing the rainfall totals for tonight and Wednesday:
Now, let's talk about timing. At midnight tonight, the rain is increasing in our western counties. If you are traveling OUTSIDE of Region 8 to the NW, notice the freezing rain:
By morning, everyone is wet:

The rain lingers around ALL DAY, and it will still be raining at 6PM:
Stay tuned for any changes! We will keep you updated on new data with the Region 8 Weather App!


Thursday, February 08, 2018

Was The Forecast Right? Let's Take a Look.

In weather verification, perception is sometimes not reality. By that, I mean that sometimes people expect something different than the reality. So, when reality does happen, they think the forecast was wrong. That's why I like to recap storms, show data to support what happened, and let you decide.

Leading up to the storm, the NWS issued an Ice Storm Warning. We agreed with this call by the NWS. According to the NWS, the criteria for an Ice Storm Warning is:

Ice Storm Warning
Issued when significant or possibly damaging accumulations of freezing rain and/or freezing drizzle are expected. This usually equates to accumulations of 1/4 inch or more of ice.

When people heard about the warning, some instantly thought it was the end of the world or the 2009 Ice Storm, whichever is worse (perception). When the panic started among a small part of the population, I posted this on Facebook and Twitter:
The reality was, 0.25" or more of freezing rain was expected somewhere in the dark purple counties. After going through reports, pictures, and official rain gauges. The forecast was pretty good! 

Was the area of 0.25" smaller than the Ice Storm Warning? YES. But, in an occupation that predicts the future, I'd take this verification every day.

I had some that question whether anyone had 0.25" of freezing rain. Yes. In fact, the official gauge at Jonesboro showed several hours of freezing rain, with a total of 0.40". All of it fell in freezing air and all of it was classified as freezing rain or "unknown precip"... which was freezing rain:

In Paragould, they also met the "ice storm warning" criteria:

So, why are some (not many) saying it was not an ice storm and why are some thinking the forecast was wrong? One of my favorite parts of the weather enterprise is the social science. Here are my thoughts:
  • Roads were slick in spots, but most were OK. I'm not a road engineer. I try not to forecast road conditions. :) Even in 2009, roads were not too terrible.
  • School was not canceled. Some gauge winter storms by school being in or out. See point 1.
  • Most people kept their power. Since 2009, power companies are 100X more prepared.
  • It was not 2009. This is the #1 reason. 
I'm about to make a bold statement. Screen grab it, write it down, or whatever:

"I doubt I will see another ice storm like 2009 in Region 8 in my life" -Ryan Vaughan

Here's why:
  • We had 1.50"-2.00" of freezing rain. That is a CRAZY amount of freezing rain.
  • Even if we had a repeat of that, power companies are so much more prepared, we would not have people without power for 3-4 weeks.
  • Infrastructure is much better now.
Anywho, that was a long post. I had some extra time and wanted to drink another cup of coffee, so hopefully I did not waste too much of your time.

Have a great day!