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Fatal storms were seen west and north of us and severe storms are ongoing south of us... Overall, Region 8 did very well with only a couple of strong wind reports. As mentioned in the previous blog post, the ingredients just split as the storm moved into Region 8. Here are the storm reports as of 5:00 PM:

I'm still watching North MS. Remember, StormCAST had their weather getting nasty around 8PM. Seems possible...

Take care and HAPPY NEW YEAR! We're having a Wii Party at our house!

Ryan

This morning, we have already had a tornado in the northwestern part of the state. As I type this, we have had some reports of fatalities in Washington County. Right now, the air is unstable and has a lot of wind shear/forcing in that area. We often look at "EHI" to determine the tornado threat. It is an index that combines the instability and "spin" in the atmosphere. The above image shows the EHI higher in the western part of the state this morning. There is a good combination of CAPE and spin there right now.But what about later? First, look at the NAM model concerning this morning:
It does a good job showing where the tornado threat is this morning. Notice, the shaded areas... especially in green where the tornado threat is a little higher. These are the areas in AR that are being threatened right now. NOW, look at this afternoon as the storms move into East Arkansas:
Notice that the EHI drops. The main dynamics that they have in NW Arkansas shoots north and the most unstable air stays south. This leave us with plain ole storms and rain. The threat this afternoon should be more in LA and MS. For what it is worth, StormCAST has had Northern MS bullseyed for 2 days for this evening!

So, in summary.... Don't let the fatal storms in NW Arkansas scare us. I really think we will be fine. We'll have some watches and some warnings, we'll have some lightning and thunder, we'll have some rain.... I just don't think we will see violent tornadoes. We'll be watching it closely.

At this time, Sarah and Justin will be handling the operations in the Storm Center and I will be chasing. If it ramps up, I will be going into the studios I believe.

Stay tuned,
Ryan

Not much time to talk because I want to go to sleep, but all evening data keeps unstable air south of us. We would still get rain and thunderstorms, but the deep instability may stay south. Here's the key... If we wake up with sunshine, that's not good. If we wake up and it's raining, we may be safe.

StormCAST data from KAIT shows severe storms in Western AR tonight (and that's happening) and then much weaker storms moving through Region 8 on Friday.... and then severe weather in Northern MS Friday evening. This may be a good bet.

I'm going to sleep and we'll go more into a "nowcasting" mode in the morning!

Ryan

The latest data coming from the NAM model has me a little more concerned about severe weather for tomorrow. The instablity is shown to be a little higher for tomorrow afternoon, which of course raises the "EHI" because it is calculated based on the instability and spin in the atmosphere.

Let me stress... THIS IS STILL CONDITIONAL! If we do not tap into the more unstable air to the south, then we just get rain and thunder, and no severe weather. Until this latest data came out, I was not overly impressed with this storm system.

We'll watch it closely and will continue to keep you update! I really, really do not want severe weather for several reasons.

Ryan

The NWS in Little Rock put together this nice graphic regarding tomorrow's severe weather threat. The grey areas show the "spin" in the atmosphere or the "Helicity". The colored areas show the "CAPE" or fuel for the storms. The areas circled by the dotted line shows the area where these two overlap the best and thus the areas of most concern. I still think the greatest risk of severe weather will be south of us, but we still can't rule out some strong storms as the front passes though Region 8.

Stay tuned!
Ryan

The SPC, or Storm Prediction Center, now has most of Region 8 in "Slight Risk" for severe weather on their Day 3 Outlook. This would be for New Year's Eve. Just like the SPC, I think there is a chance of severe weather, but it is what we call "conditional". IF we see the air become unstable with the help of some sunshine.. then the risk will be higher. As of now, I'm just not completely sold on severe weather. We WILL see storm with lightning and thunder, but I'm not sold on seeing large hail, damaging winds, and tornadoes. The MAIN threat would be damaging straight line winds.

Here's the setup.  Notice the warm air surging northward ahead of the surface low. This is the lunch hour on Friday from the GFS:
We will at least have temperatures in the 60s across Region 8. This will help us to be more unstable. If we start to see widespread 70s... we may have a higher storm threat. This next map shows the CAPE, which is the "energy" to fuel these storms. Notice the highest amount of "energy" is to our south. That's the main thing we're lacking for severe weather. No complaints here! I'm "suppose" to be off work.
Remember, the air can be much more unstable if we really get a surge of warmer air and we break into some sunshine. One thing we are not lacking are winds. The map below is the 850mb winds. Anytime I see winds over 35-40 kts at 850 mb in a convective setup is a red flag for me. As mentioned earlier, straight line winds look to be the main threat for these storms. I'd be shocked to see large hail as I don't think these storms will be building up too high... Anywho, note the shaded areas:
If we get some of those winds to transport down to the ground, we could see some damage in some of the stronger storms.

If it gets too nasty, I will be at work. Otherwise, J-Lo... aka Justin Logan will be holding down the fort.

While parts of Region 8 did have a dusting this morning, all we had at the Vaughan house was a few flurries. Here's a map showing the snow depth this morning across the United States.

Notice that is shows some what over Region 8, but the dusting reports are not widespread. If anything, I'd say spotty reports. Look how close we were to seeing a good snowfall! Since this map was created, some good snowfall has been falling in MS, AL, and GA as well!

I hope everyone is having a very Merry Christmas. From the Vaughan house to yours, I hope God blesses your day as we remember the birth of Jesus!

EDIT: Good point made by Patrick Marsh. See the later map on his blog. It includes the snow in MS,AL, GA I mentioned. Here's his comment in the comments section:


Just an FYI: This image was generated at 1AM EDT on Christmas Day, and was valid for the preceding day. Check out the link below to see images valid for Christmas Day.

http://www.patricktmarsh.com/2010/12/day-360-white-christmases-a-noreaster 

Ryan

Right now, it is COLD outside, but that will be changing. Warm air will start moving in from the south and as that warm air moves over the cold air, we will start seeing rain develop on Wednesday. I think we will warm up enough for it to be all rain, but I can't rule out some BRIEF sleet at the onset Tuesday night into Wednesday morning. The bulk of this type of rain (overruning rain) will fall on Wednesday, although showers are still in the forecast for Thursday as warm air continues to move in from the south. At this point, I'm eyeballing Friday. It's a big day for people. Many will be heading out to New Year's Eve Parties and the weather will impact your day and night... whether it is severe or not. So, let's talk about it.

First, the temperatures are going to be warm! Look at the map for midday on Friday:

The "circle" in the northern part of Missouri is the surface LOW. It has a counter-clockwise spin and typically draws in warm air, ahead of the low at the surface. In the map above the 12Z GFS has the mid 60s into Arkansas and I believe that if we see some breaks in the clouds, 70s will be possible in the state. In addition, the dewpoints appear to be in the 55-65 range. Typically, we need dewpoints over 55 to have the "juice" to support strong storms. This appears to be in place on Friday.

Now, let's talk about other variables. We appear to have some upper-level support and shear to support  strong storms, but overall instability could be lacking. Below is the CAPE map. More or less, this is the fuel to get the storms to build:
Notice, the greatest instability is down to our south. I'm not saying this is not enough to spark some strong storms, but the greatest CAPE stays well south it appears by the GFS... and other models. There is a chance that the GFS is not playing this up as high as it could go, but we'll watch it.

This next map is the lifted index map. Pretty much, thunder/lightning is possible in areas with negative numbers (colored areas). It's not that cut and dry, but it's a good starting point. Notice, we do run the risk of at least hearing some thunder from nature's own New Year's Eve Fireworks!
Models are not agreeing on what happens after this storm system, but I think most of the precipitation is gone by New Year's Day. We'll see though...

Maps provided by my friends at www.twisterdata.com

Stay tuned,
Ryan

The GFS model continues to show a monster low in the middle of the country on New Year's Eve. With the low to the NW, we would be on the warm side of the storm system. I would expect temperatures to be somewhere near 70 degrees dependent on cloud cover and thunderstorms.
The above map simply shows instability. I'm not going to get too cutesy on this forecast 7 days out, but I wanted everyone to know that possibility does exist for severe weather on New Year's Eve if this materializes.

Stay tuned!
Ryan

I'm pretty much sold on the fact that we will not see much... if anything. A dusting is still possible, but without the merging of the northern and southern branches of energy, we're not going to get a big snow. Flakes will fly, some may panic a little over a dusting, but in the end... it will be weak. I think StormCAST has a pretty good grasp of the GREAT CHRISTMAS EVE DUSTING!

As mentioned earlier, we really need the upper-low (bullseye in TX) to the south to merge with the big "U" sliding in from the north. As you can see in the bottom image... the NAM still takes it south as well as other models:
Oh well... I guess there is still some time for this to change, but at this point, don't count on it.

Now, we start watching a strong storm that may develop near New Year's Eve! Severe weather? We'll see...

Ryan

In order for us to get a good snowfall, two pieces of energy need to merge together before passing us by and heading East. The data keeps flip-flopping back and forth on whether this will happen or not. It's called "phasing"... Let me explain. The map below is the latest upper-level forecast data for Christmas Eve from the NAM model. Click to enlarge. I have circled the two pieces of energy. The top one is the northern branch and the bottom one is the southern piece of energy. Notice, they are NOT together. They are NOT merging. This would yield little, if any, snowfall for Region 8. Maybe a dusting.

Now, let's look at the data that we had last night. It was more promising for a decent snowfall in Region 8. It had both pieces of energy merging together or "phasing". This image is for the same time period on Christmas Eve, but shows a totally different outcome:
If this were to occur, a good 1-3" of snow would occur across Region 8. It's amazing to see how much flip-flopping we are seeing in the data! This really may be a wait and see situation. We'll know more tonight and tomorrow morning as this system evolves.

Stay tuned,
Ryan

This was the latest data when I left work last night from the Region 8 Storm Center.This would be perfect for me, personally. If we pick up more than 2" or so, I would likely have to work on Christmas morning! I'd rather be home with my family. We'll have the latest data with each newscast. Join Justin at 11 and me at 5,6, & 10.

For what it is worth, there is still some data that suggest only a dusting... at best!

Stay tuned!
Ryan

Data is trending more and more to the low passing south and we only getting snow from the northern branch of energy. That would still give us some snow, but it would only be about 1" at best. Maybe 2" in MO areas.

Stay tuned,
Ryan

For the past few model runs, the GFS has been taking the low WAY south. In fact, it is leaving out ANY precipitation. No snow, no rain, nothing. The above image shows the upper low sliding south of us on the 12Z GFS. This would mean NO white Christmas. However, we still have the NAM.... Here's the 12Z NAM
Notice, the NAM has the low farther North and tapping into the northern branch bringing down the cold air. THIS would give us a White Christmas! Look at this data in the BUFKIT program. The timestamp goes from RIGHT to LEFT:
It's still too early to at this point. Hopefully the models start coming together over the next 12-24 hours. I'm still leaning to us getting some snow, but it's what we call a "LOW CONFIDENCE FORECAST". Let's let the low come inland a little more... shove some weather balloons into it... and get a better grasp on it!

Stay tuned!
Ryan

I'm waiting for some new data before I post an update. One model has 2" of snow and another keeps us dry! Stay tuned.

Here's the snow output from the 18Z NAM (Midday data). Maaaaan, I'd be happy if this panned out. Once again, this is a model and NOT a forecast! With it being Christmas Eve and all, I'm trying to show you some exciting maps, but this snow forecast is FAR from being nailed down. There are still several hours in between now and then...

Stay tuned!
Ryan

The morning started to get interesting when the 12Z NAM data arrived.When forecasting, we often look at the 540 decameter line as the rough start to determine the rain/snow line. It's not always right on that line, so if you live by the 540 line, you'll also be burned by it. But, it is a good starting point.

The above map is for the lunch hour on Christmas Eve. That's as far out as the NAM model goes for now. Notice the blue line... that's the 540 line. Based on some other variables, I think the rain snow line will be a little farther south than that line.

Now let's look at the GFS model. It goes out farther and really gets me more excited. :) Here's the GFS on Christmas Eve. at the lunch hour:
It has the rain snow line farther south and a big slug of moisture moving through. And then it gets even better...
The rain/snow line dips farther south and we still have moisture, which would be snow if this played out... and also snow for Nashville if my family and friends over there are reading! Here's how it looks graphically on BUFKIT:
If it played out like the 12Z GFS indicated, a lot of people will be happy in Region 8! Keep in mind, this is a model and not exactly a forecast! At this time, I'm not sold on this enough to call for accumulations. I just want to get your hopes up a little! LOL

One more map to show you... This is a map created using an algorithm based on the 12Z GFS. Wouldn't this be nice:
Don't get excited yet... We'll keep watching it! Maybe working on Christmas Eve will not be that bad...

Ryan

The short answer to this is... maybe. It's not likely, but a "weak" maybe will do for now. First off, what is a White Christmas to you? Is it one inch of snow? Is it a dusting? Is it flurries? We had a dusting of snow on the ground as we opened presents in Nashville (Murfreesboro) this past weekend. We considered it a White Christmas because we are southern and we can call it whatever we want... even if it was December 17th! But what about CHRISTMAS! See maps...

The above map is the GFS from this morning. It shows the bulk of the precipitation during the days on Friday and the rain/snow line "just" north of Region 8. In fact, some of our fringe counties may see some accumulation based on this data. Anyone traveling north? See map:
Now, the European model gets us a little more excited.... This is Friday night. Low is well south of us and the rain/snow line is in Arkansas! This map is from the Accuweather Pro site. Great site for Euro data.
If this played out, I would at least expect a dusting for parts of Region 8 on Christmas morning.

One last note... This is the most optomistic. The GEM puts 1-2" of snow on us by Christmas morning:


Too early to tell right now, but we'll see.

Stay tuned!
Ryan

This is a little nugget of data that uses the Cobb Algorithm to decide the precipitation type using the NAM model from this evening. A few things to note when you click the image to enlarge:

• The hours surrounded with a red line are the hours noted with freezing rain.
• The areas in green are the hours noted with plain ole rain
• The yellow area is the temperature column.
• The blue is the "total" QPF or total precipitation.

We've got the potential for an icing event by the middle of the week, but don't get too worried just yet. It's not going to be a BIG ICE STORM like we had two years ago. Get that out of your mind first!

The above image is BUFKIT showing the latest GFS model run. The timebar goes from right to left (you guys should know that by now). Anywho, it shows some icing through the day on Wednesday, as indicated by the red bars. The red line is the temperature and I have made a "freezing line" in light blue.

The GFS does have us at or below freezing as the precipitation moves in. This would lead to some light icing if this happened. Two things to note. First, models have a hard time handling shallow cold air. (I'll explain shallow cold air shortly) Second, notice the big gap between the green and red line. That is the difference between the temperature and dewpoint, which indicates dry air ahead of this system. This should lead to some "evaporative cooling". Lick the back of you hand. Go ahead... it's cleaner than the palm of your hand! Now, blow on it. Colder?? That's evaporative cooling.
NOW, the above image is the NAM model. It has us warming above freezing before the moisture arrives! Remember though, models have a tough time handling temperatures in this setup. We could be colder. Regardless, there is not a TON of moisture with this, but enough to cause some slick spots if it happens.

Now, what do I mean when I say "shallow cold air"? Below is a forecast Skew T of the GFS model...
This is a single point in time (1PM Wed) and it shows the atmosphere from bottom to top. I have colored in some areas to help show what's happening. First, the blue area is the freezing area. The red area is above 32. The "shallow" area of cold air is the freezing air at the bottom. Water falls through that air, and may not have time to freeze before it hits the grounds, but it freezes on contact as a "glaze"... if it DOES freeze before it hits the ground, it is sleet.

For it to be snow, the entire column of air would need to be at or close to 32.

Latest run of the GFS model (Midday Run) shows that it could snow Saturday night. Let me preface this by saying that I'm not sold on this. It COULD happen... It COULD, but it's just not the perfect setup. The above image is the BUFKIT program (click to enlarge). The timestamp goes from right to left. It shows the rain coming in this Saturday and it shows the nosedive in temperatures. This data suggests that there will still be some moisture in the area as the very cold air moves in Saturday night. IF this happens, we could see a little dusting. My confidence is low and it is only Monday, so let's not get too excited yet!

Stay tuned!
Ryan

Justin Logan is hard at work tonight making maps that we can "manually" enter current conditions onto. Normally, the current conditions update automatically, but something has screwed that up today.

In April, a satellite named Galaxy 15 stopped taking commands from Earth. It was launched in 2005 and was suppose to last 15 years. It only lasted about 4.5 years... well, kind of. You see, it still has power!  It's flying about 22,300 miles above us and is out of control. This has happened in the past, but this is the first time that a satellite has been uncontrollable while still trying to find signals to rebroadcast.


Today, it has interrupted the feed from the NOAAPORT Satellite that feeds us several pieces of data. This is not something that was a complete shock, but I'm worried this may be an ongoing problem. In fact, I see this notice that says we may experience more problems in a week:

http://www.nws.noaa.gov/dm-cgi-bin/chgshow.pl?fn=DMPD111005.txt

I hope that does not happen!

UPDATE: As I was typing this, Justin sent me a text saying that the data was returning! WooHoo!

Ryan

It's shortly after 10:00 and the colder air is moving in. It's 44 in West Plains and 59 in West Memphis! The front will continue to move through, with an increase in clouds and just a 10% chance of a sprinkle. The colder air will stick around for a few days. The below graph shows several models, the NWS forecast, and the observed temperatures so far today...

Still not sold on the snow, BUT let's look at the snowiest data I can find in order to wishcast it to Region 8! This is the 6Z (Midnight) run of the GFS model for Monday Night:

The blue line is typically a good starting point for the coveted "rain/snow" line. LOOK, we're north of it!!! *wishcast, wishcast, wishcast*

The green is precipitation and it shows some on Region 8! *wishcast, wishcast, wishcast*

Next image is the data in graphical form...
This is BUFKIT and the blue lines indicate snow on this model run for Monday evening. *wishcast, wishcast, wishcast* The purple/yellow lines are the best places for snow to form. The yellow area is the "best" environment for snow dendrites to form. *wishcast, wishcast, wishcast* IF this happened, we could see 1-2" of snow in parts of Region 8 and more in SOUTH of us in Central Arkansas. Look again... that's a big "if".

Let's did a little deeper...
I added a few more things to the graph. I added RH (Relative Humidity) in the red and green to show that we will have moisture. I also added surface temperature with the red line, which shows we'll be cold enough. *wishcast, wishcast, wishcast* I also added "Omega" which is the rising motion of the air. It's not that impressive, which leads me to think that this is NOT going to be a big storm. Let me clarify... If we see 1" or less, I consider that to be minor. Sorry, snow lovers.

Once again, this is me searching for the "snowiest" data I can find. Most data suggest dry, but still cold. We'll have a slight chance in the forecast regardless until we get closer to next week. *wishcast, wishcast, wishcast*

In fact... the latest GFS data coming in shows even less moisture. Flurries.... Keep Wishcasting everyone! LOL

Ryan

I'm posting this as a test. This is my first post using my phone. As you can see, the cold air is plowing through the country. We're expecting lows in the 20s tonight and the skies will continue to clear out.

Enjoy!
Ryan

There is some chatter in the weather world about the chance of snow for next week. First, let's remember that we are talking about the forecast for 8 days out! That can be tricky, at best. BUT, the Euro model has consistently shown the possibility! The below map of the European Model was created from Accuweather Pro and shows precipitation (green) and it shows the rain/snow line (blue line) south of us.

IF this happened, we would have a decent snowfall on Tuesday, December 7th. That would be pretty cool, considering the Paragould Christmas parade is that night. :) And fellow Nashvillians that read the blog, you would be in line for snow, too.

BUT WAIT! This is not guaranteed! Another long range model we use is the GFS. IT shows cold air, but no precipitation. This model image is from NCEP.

Here's the deal. Like "Dumb and Dumber"... I'm saying there's a chance. I'm just not getting too excited 8 days out.

Stay tuned. I'll be posting through the week about this setup. Also... stay tuned for possible severe weather later today... especially in Southern Areas.

Ryan