Five years ago today (February 16, 2001) quite a weather event took place across Arkansas, Mississippi, and Alabama. A Derecho is a long-lived and widespread convective wind storm, typically in the form of a large, bow-shaped squall line. Derechos often last for several hours, and can produce wind damage over thousands of square miles. They can travel at speeds over 50 mph, and may contain wind gusts of 70-100 mph.

The event of February 16, 2001, actually began rather innocuously, in parts of Texas and Louisiana in the early morning hours, where a band of showers and thunderstorms developed and started to move east. Through the rest of the morning and early afternoon hours, the storms became more intense and formed into a more organized line as they marched across Mississippi. Damage from wind gusts was reported in several Mississippi counties as the line moved through. Damage was widespread in the Starkville-Columbus area, including the campus of Mississippi State University. A total of eleven people were killed by this system in Arkansas and Mississippi. Many people had no power for weeks.

The line of storms reached the western Alabama border around 2 pm. Around the same time, a section of the squall line began to bulge out, or bow, in Pickens County. Through the next 3 hours, the Derecho would move across the entire width of the state, producing wind gusts to 100 mph, and widespread damage similar to an F0 or F1 tornado. The ABC 33/40 Weathernet site atop the press box at Legion Field measured a gust right at 100 mph. Officially recorded wind gusts include 60 mph at the Tuscaloosa and Anniston/Oxford Airports, and 68 mph at the Birmingham Airport and Gadsden/Etowah County EOC.

(Thanks to the B'ham NWS office for part of the material used in this post)

The Wednesday afternoon map discussion video is on the server:

http://beta.abc3340.com/weather/video.hrb

While we enjoy some spring-like weather here today and tomorrow, our attention is focused on extremely cold air moving into the northern U.S.

As I write this, the temperature at Flag Island, Minnesota is two degrees below zero, with a wind chill index of -18. Warroad, MN reports 0 with a wind chill index of -16. Ouch.

Before we deal with some of that kind of air, we will have a very mild day tomorrow. See no reason now why we can't reach the low 70s in most areas. Spring fever could become a real issue!

The front begins to nose in here Friday; the temperature forecast will be a challenge, but it looks like highs will drop into the 50s. Maybe colder up in extreme North Alabama.

NASTY WEEKEND: I actually like a cold and wet weekend. Maybe nasty isn't the right word. But, if you will be at a baseball practice, it will be nasty. A shallow layer of cold air moves into the northern part of the state, and warm moist air runs up and over the cold air meaning clouds and periods of rain.

As discussed many times here in recent days, the cold air will only be 2,000 to 3,000 feet deep, so most models won't know it is there. For the I-20 corridor, I think this keeps temperatures in the 35 to 45 degree range this weekend. We will be close to having some problems with light bridge icing early Sunday morning as far south as Birmingham.

But, the best chance of significant ice problems will be up north, over far North Alabama and Tennessee. I think the general area between U.S. 72 and I-40 will be especially problematic Friday night and Saturday. There could be enough ice accumulation for very difficult travel, and maybe even some power outages. North of I-40 the cold air should be deep enough for snow instead of freezing rain.

It certainly looks now like the greatest winter storm impact this weekend will be over Tennessee and Kentucky, but I sure can't rule out some bridge icing problems down into North Alabama, especially Saturday night and Sunday morning.

NEXT WEEK: I am not really convinced the front will move much at all. We stay cold and wet Monday and Tuesday. Yes, the shallow cold air should modify some, but not as much as you might think. That is a cold, dense airmass to the north. The high in Chicago Saturday should be around 5 degrees.

The 12Z GFS has flipped on the severe weather threat around Thursday 2/23; it now shows a cool and dry day. Confidence is very low at this point in anything specific beyond seven days. A tough pattern.

And, in the long range, our warm ridge that was showing up a few days ago is way down in the central Gulf of Mexico. Sure seems like the rest of February and the first part of March will feature some very cold air for the northern half of the nation, and lots of rain here as that Arctic air tries to press southward, but runs out of gas. A stalled front seems to be within 100 miles of us most days for the next two weeks. Looks really wet. Probably cold at times, and stormy at times. No dull days around here.

WEATHER BRAINS: We loaded this week's Weather Brains show on the server last night... David Black does a great job with that show. Listen here:

http://www.weatherbrains.com/

Or, via iTunes.

STORM ALERT 2006: Yep, we are coming to TALLADEGA tomorrow night... our annual severe weather awareness show kicks off at 7:00 p.m. at the Ritz Theatre on the sqauare. Get there early for a good parking spot and for a t-shirt!

The next map discussion video will be on the server by 7:00 a.m. tomorrow...

* 71 is how warm it was in Tuscaloosa at 1 o'clock this afternoon. It was only yesterday day morning that they had a low of 25 and Monday morning 22. That is almost a 50-degree recovery

* 83 was the USA high yesterday in Laredo

* 29 below zero was the USA low this morning in Embarrass, Minnesota

* 31 is the number of inches of snow still on the ground atop Mt. LeConte in the Great Smoky Mountains this morning.

* 2 inches is all that remains in Gatlinburg after a high of 53 yesterday

* 22 was the low this morning in Barrow, Alaska. That is +22 because temperatures have moderated a lot across Alaska

* 0 is the number of times I have been to Monroeville or Dothan, Ala., they are both on my to go to list

* 0 is the number of times I have been to Panama City

* 3 is the number if times I have been to Atlanta (passing through each time)

* 4 is the number of cups of coffee so far today. (gotta catch up)

* 0 is how many times I have watched Desparate Housewives on TV

* 1 is how many times I have watched AmericanIdol since it has been on the air

* 0 is how many sausage and biscuits I have had in the last month (yummy, yummy)

* 15,330 days is how long I have been a weatherman

* 24,455 is the number of days I have been interested in weather

The third episode of the podcast "Weather Brains" is on the server... you can listen here:

http://www.weatherbrains.com/

Weather Brains is also available on iTunes...

This week there is a great feature on the show about long time cooperative observer James Price from Pinson, and we talk more about winter weather forecasting.

Check it out when you have a few minutes!

The Wednesday morning map discussion video is on the server:

http://beta.abc3340.com/weather/video.hrb

Lots to discuss this morning.

BIG TIME COLD UP NORTH: Brutally cold air is creeping into the U.S... as I write this Hallock, MN is reporting 20 degrees below zero. Over in North Dakota, Grand Forks is down to 17 below. Bring in the brass monkey. Ouch.

MID-WEEK WARM-UP: We should be in the 60s today and tomorrow, a nice break from the recent cold snap. Moisture is also increasing, so there will be plenty of cloudy periods. Guess we might see a sprinkle or two today or tomorrow, but significant rain isn't very likely.

FRIDAY FRONT: The leading edge of the coldest air of the winter will dip into North Alabama Friday, making for a nightmare temperature forecast. For now we will forecast mostly 50s on Friday, but there will probably be a huge range from Muscle Shoals to Montgomery. And, a few showers are likely near the front.

WEEKEND ICE? The front settles into Central Alabama over the weekend. On Saturday, Huntsville could have a high of 35 while Mobile has a high of 75. The cold air will be very shallow, only a few thousand feet deep, so the "0 line at 850" and the "540 thickness" line won't really serve us well in this case. The GFS MOS also will struggle. We have Birmngham in the 35 to 39 degree range on Saturday with periods of rain. That will be a cold rain.

To the north, ice will be a big problem on Saturday over much of Tennessee, and perhaps extreme North Alabama. Be aware of this if you are traveling north.

Saturday night, the cold air continue to seep southward. By 6:00 a.m. Sunday, the 06Z GFS has the 32 degree line at the surface from about Hamilton to Collinsville, meaning of course any rain that falls north of that line will be freezing rain along with the chance of ice on exposed objects. I still think based on the strength of this Arctic high that freeze line might be closer to I-20, and I can't rule out some light bridge icing as far south as Birmingham early Sunday morning. No, I don't think it will be a major issue, but just something to keep in mind.

There is no doubt the greatest chance of significant ice will be over far North Alabama and Tennessee this weekend.

Sunday temperatures should rise above freezing with more rain.

STILL WET NEXT WEEK: That surface front should drift north of us Monday, but rain should continue at times all the way through Wednesday as it meanders around the Deep South.

SEVERE WEATHER? The 06Z GFS has an interesting solution around Thursday of next week (2/23), showing a strong central U.S. short wave and a surface pattern which favors Alabama getting in the warm sector along with a severe weather risk. This is just one run; lets keep an eye on it. We don't like to be specific beyond seven days, and this might vanish on future runs. But I find it an interesting idea with some credibility.

LONG RANGE: The long range looks different in the latest model runs. The warm ridge isn't there anymore... there are hints at other severe weather possibilities followed by cold air intrusions. Low confidence pattern, to say the least. February and March often feature wild weather swings. Be ready for anything and everything.

STORM ALERT 2006: Don't forget our weather team is coming to Talladega tomorrow night... our show begins at the Ritz Theatre on the square at 7:00... get there early for a good seat!

The next video will be on the server by 3:30 this afternoon!