Thanks for reading and have a great night, we will be back with the latest information when we can!
~Michael, graphics provided by Cameron
As promised, we are bringing you guys an updated look on the pattern, as I have mentioned before, this blog will not be overly long because we are still in long range, but getting closer. I will be giving a couple of scenarios that could be possible as we move closer to this event.
This is scenario 1, this is one of the possible jet stream tracks (which we think may have a better chance of happening) due to the consistency in the models with this particular pattern. This is typically the jet stream that gives us the active weather. This can be anything from wintry precip or just rain, given the set up. Being far out, we WILL NOT GUARANTEE ANYTHING. We will continue to say that the pattern we are moving into COULD favor wintry precip. Winter weather is still on the table but IS NOT GUARANTEED!!!!!
This is scenario 2, this jet stream pattern is less favorable for winter weather events due to how close the storm track is to the state. This wouldn't allow as much cold air to mix with the system, and allow warmer air to move farther north, meaning ice would be more of a threat with this kind of pattern. Once again, THIS IS NOT A FORECAST! All we're saying is the pattern may eventually favor winter weather here around Christmas week, but these blogs won't be overly long until then. Up until about the early-mid part of next week, the blogs will mainly focus on the overall pattern.
Thanks for reading and have a great night, we will be back with the latest information when we can!
~Michael, graphics provided by Cameron
Firstly I'm going to say. NOT A FORECAST!
The model I'm going to use at the moment will be the GFS...why? A couple reasons, one, it has been consistent with its runs, and two, it's currently the only global model to be able to see this far. This blog won't be overly long because it's just update number 1. Tons of uncertainties, but just going over the pattern real quick. *Will only focus on the jet stream this early in the game*
1. This dip in the jet stream is important. It will play a role on what may happen here. When the jet has a dip like this, it will send storm systems (if any) southeastward instead of north...meaning that if they get far enough south...and IF moisture is involved, winter precip may be the result. In this run, the jet is decently far enough south.
2. The subtropical jet stream lives here, if it's active, which it looks to become active, it will supply moisture and occasionally storm systems. An active subtropical jet will aid in the development of winter storms.
3. When the jet lifts northeastward like this, it is not only supplying moisture, but signifying that the subtropical jet is playing a role in supplying moisture. It also signifies cold air may be in the mix. We will also be watching for things like that too.
Remember, this will ALL change, but the consistency the model has shown has warranted the need for Christmas time blog updates. These blogs will get bigger with time, if data continues to show the possibility of a winter storm event. My personal thoughts on this, it is too early to know whether we have a rainy Christmas, snowy Christmas, Icy Christmas, or a even a dry Christmas, but, the chances for an active Christmas week are slowly rising, and will continue to rise if data continues to be as consistent as it is. We will keep monitoring this potential for y'all. Thanks for reading and have a good night!
**This was bothering me to leave any of those wondering, so just decided to update and mention that those waiting for the app, we are still waiting for apple and google playstore to approve it for us, we have given the multiple calls asking what was going on and they said they would "get to us when they could". Just giving y'all an update because it was bothering me to leave y'all in the dark.**
Since we are going into winter, I am going to take advantage of the fact that we haven't had any serious cold or winter precipitation yet to give you guys a rundown of the hazards in winter time. Some of them are less common here, some of them are more common, but they can occur any time the weather looks like it could get dangerous.
1. Wind Chill Advisory: This is issued when wind chills will likely drop down to/drop below -15 degrees F within the next 12-36 hours.
2. Wind Chill Watch: A wind chill watch is issued when conditions are favorable for wind chills to drop far enough to warrant a wind chill warning in the next 24-72 hours. Wind chills may drop to/drop below -25 F.
3. Wind Chill Warning: This is issued when wind chills will likely drop to or below -25 F within the next 12-36 hours.
What are Wind chills? Wind chills are when the temperatures are low, and a cold wind (often north or northwesterly) occurs while temperatures are low and makes the air temperature feel even lower than what it actually is. Wind chill is very dangerous and can lead to frostbite if you are outside long enough.
4. Winter Weather Advisory: A winter weather ADVISORY is issued whenever the likelihood of wintery precipitation is high, but the event overall does not appear significant. Though this does NOT mean that whatever falls will not cause inconvenience.
5. Winter Storm Watch: A winter storm WATCH is issued when conditions are currently favorable for a winter storm event. This can include "heavy sleet, heavy snow, ice storm, heavy snow and blowing snow or a combination of events" to meet the criteria for a winter storm watch. Conditions may rapidly deteriorate within the next 24-72 hours. "Criteria for snow is 7 inches or more in 12 hours or less; or 9 inches or more in 24 hours covering at least 50 percent of the zone or encompassing most of the population. Criteria for ice is 1/2 inch or more over at least 50 percent of the zone or encompassing most of the population. This includes lake effect snow."
6. Winter Storm Warning: A winter storm WARNING is issued when hazardous winter weather conditions are imminent and/or occurring. "Heavy sleet, heavy snow, ice storm, heavy snow and blowing snow or a combination of events" and will meet warning criteria in the next 12-36 hours. Criteria for a Winter Storm Warning is "for snow is 7 inches or more in 12 hours or less; or 9 inches or more in 24 hours covering at least 50 percent of the zone or encompassing most of the population. Criteria for ice is 1/2 inch or more over at least 50 percent of the zone or encompassing most of the population."
7. Ice storm warning: An ice storm WARNING is issued when an ice storm event is expected to cause significant issues to travel safety within the next 12-36 hours. Criteria for an Ice Storm Warning is a 1/2 inch of ice within a wide area.
8. This doesn't happen here, but just in case someone has a problem with this if they're ever traveling, I will add it anyway.
Lake Effect Snow Warning: This is issued when "widespread or localized lake induced snow squalls or heavy snow showers" that produce 7 or more inches in 12 hours or less. These are issued 12-36 hours in advance of the event.
Lake Effect snow events are not often widespread, they're typically narrow bands affecting a small area.
Thanks for reading and have a good rest of the day!
~Michael, some assistance from the National Weather Service description page.
This blog will show just a couple frames on the GFS (since it is the only model that will see this far out and is a global model). First picture is out of the 6z (early morning) run.
The 6z GFS showed us getting hammered with a snowstorm towards Christmas. This WILL/HAS changed. I will only point out some things in this GFS run, firstly, this is a good setup to get big time snows in Arkansas. The two high pressures across the northern plains and southern high plains are causing a moist, northeasterly flow, meaning that this will not be a dry snow, but wet snow that is displayed on this GFS run. The next thing, the system over Mexico, that system is ALSO supplying moisture into the state from the south, this is aiding in the development of snow. The reason that the model currently shows ice/mix over Arkansas is that the lower atmosphere isn't favorable, but is gradually becoming favorable, for snow. Refer to my last blog for this and the next thing I will cover. The next thing making this a favorable pattern for snow is that the jet stream will be strengthening over us, on top of that, the jet stream isn't cutting off the subtropical jet. The subtropical jet is also active in this run. Remember, to make sense of what I just said if you don't know what I mean, refer to my last blog for a refresher. This DOES and will continue changing, so don't take this to heart. Though we will begin watching later this month for something maybe, still a wait and see.
Here's the 12z (morning) run. This run is obviously different from the 6z GFS. I do not completely agree with all rain though. On top of tha the date is different, but it is the same storm system just coming through earlier. The GFS in particular, doesn't do too well in the long range at all...meaning that I'm not writing this all off as rain. This is still a monitoring time period, but the pattern we are in, if we can get some adjustments such as a more active subtropical jet stream, and a decently placed jet stream with moisture involved, we could possibly get a decent snow in Arkansas. We will keep watching for you guys and letting you guys know of updates.
Have a good rest of the night
Also....no super long blog tonight! Just a little educational blog with an idea of snow towards Christmas time that I thought would make it special.
Welcome to the first blog of the 2017-2018 winter season! This blog will be FULL of amazing information, especially those that love winter weather. First things first, this WILL be a lengthy blog, covering three cold shots, potentially a brief warm up, it will cover all global models (GFS, Euro, CMC, JMA, and the NAVGEM for the short range), as well as the overall pattern, and the upper/lower levels (out of the GFS, CMC, and Euro). I will be covering the 18z and the 0z runs (afternoon and overnight) of the GFS and NAVGEM, and 0z (overnight) runs of the Euro and the CMC. I will be using the 12z (morning) run of the JMA. If you are not a weather geek, do not worry! This will be simplified once I go over the actual data for y'all.
The current pattern
The pattern we are in at this very moment features a gradually increasing flow from the south as a high pressure moves away from the area, which in turn will increase moisture over the area. For winter lovers, this isn't a good deal, this means that warm air will ALSO be streaming over the area, resulting in warmer than normal temperatures. Focused on Arkansas, this is the pattern near/over Arkansas, will only use the GFS since models are in 90-100% agreement this close.
This is the pattern we are gradually moving into. A southerly flow will warm things up. Notice, the red lines that are perpendicular to the arrows, they also have numbers on them. These are isobars, they represent temperature above the surface (and occasionally the surface). When they are red, and the numbers get larger, this means that the atmosphere and surface are warmer. When the isobar commonly referred to as the "Rain/snow line" appears, it will show the number "540" and turn blue. This means that the atmosphere has reached 32 degrees or below (the lower your number gets the colder, vice versa with warm), and occasionally once the 540 line passes you, temperatures at the surface hit 32 or below. Not always though. Quick note: When you are well within the 540 line and hitting lower numbers, your surface temperature will MORE THAN LIKELY be below freezing. You will see the 540 line several times in this blog.
This is the overall pattern we are currently in, and will be in all weekend until a storm system abruptly ends this pattern, the "Zonal Pattern" means that there is little to no amplification within the atmosphere, or, in a simplified state, storm systems remaining well north of us and mainly affecting the northern US, those storms travel within the blue line. This is the jet stream, so storms that re curve in the western pacific will ride along that line and leave us with warm temperatures and a very dry atmosphere. The other part of a zonal flow is that your subtropical jetstream is not very active either, that is the green line. Storm systems ride this stream as well, but when it IS active during a zonal flow, it'll skip us and move on because there will be no amplified jet, or, dip in the jet stream over the western US to pick it up. That...will likely change next week.
Next weeks pattern
Next weeks pattern will feature an amplified jet, dip in the jet stream, meaning that we can finally get storm systems down here, but, there could be a problem with this. Will hit on that part later. First, will talk about what the pattern changing front will do.
This is, of course, the pattern for late next week. Now, let me say this, the pattern next week is NOT GUARANTEED, but VERY likely, because models agree on it. There is still the potential for models to suddenly flip, but this is highly unlikely as we are pretty far into the ballgame in regards to consistency. How cold, how long will it last, and what kind of precip are all in question until we get more consistency on intensity of cold air. Before anyone gets too excited, this pattern DOES mean more storms, but...it is also not a favorable pattern to get big time snows. Why? Because remember the subtropical jetstream over the Gulf of Mexico. Remember 1. It has to be active and 2. it can NOT be blocked off. When you have a jet stream THIS far south, it can totally shut off moisture/storm systems from affecting us that are riding the subtropical J because there's no possible way it can sneak under that jet. There is still hope, as 1. The subtropical jet DOES look to become active right when this cold blast happens, and 2. could or could not be blocked off. We still need to monitor how far south the jet stream goes, if you line them up perfectly and get a system, that's a good set up for a good snowstorm. Will save that bit for later though. Now with this sudden change in the jet stream, there will be rain that will be associated with a strong cold front. Will it bust our drought? Eh...it is possible, but I'm not going to give a complete yes just because of how far we've dipped into the drought, now some burn ban removals ARE likely, but that depends on the county judge. Before we get into the models, I want you guys to look at where it says a storm system is possible on the 13-15th of December timeframe. The GFS (18z-afternoon) will be used to show what we mean.
First up, the GFS! The GFS has been decently aggressive with its cold shot, and even more aggressive with its second cold shot, a run or two ago taking us down into the teens. Of course take this with a grain of salt as data will/continues to change. Here is the pattern changing cold front.
Here is where the GFS thinks the front will be Monday afternoon of next week, all of this will change so when I say what the GFS is saying, remember, it will change. As such, here is the frontal location for next Monday afternoon. As you can see, the red arrow represents rapid moisture return, and as weather geeks know, is represented by the bumps in the isobars, as well as increased moisture over the state. Showers/isolated thunderstorms increase ahead of the front.
This is the GFS for Monday evening, the GFS suggests that rapid moisture return shifts into the Southeastern United States, with the Jet Stream (big blue up and down arrow) gaining amplitude as it dives southward behind the cold front. The giant blue arrows represent cold air diving south behind the front too, remember the 540 line we talked about? Well there it is, and it is moving towards Arkansas currently, that will be our first cold shot. Meanwhile, ahead of the cold front, showers and isolated thunderstorms have developed and are pushing across the area. Recall how the 540 line was often nicknamed the "Rain/snow line". That is because that's where rain often changes over to snow. The cold air lags too far behind in this GFS run so no snow occurs. (There have been hints at random snow potential late next week within the models so will continue to monitor that but in forecasts) If the cold air were to speed up, and the moisture lag behind some more, we could have some areas of flurries/brief light snow behind the front.
This is the first, strong cold shot, this is after the front has passed. This is the problem, the reason the system up north totally skips us on snow is because it is dry down here. Why? Because the subtropical jet (orange) is being blocked off by the jet stream. All of the moisture that would cause a big snowstorm down here is stuck along/below the subtropical jetstream. The atmosphere above the jet stream is cold and relatively dry, that storm system on the Illinois/Indiana state line has maintained its own moisture. This system is lifting off to the northeast, so it will not affect us other than stronger winds and cold air. There is the possibility of a snowflake or two in NE Arkansas, but of course this data will change so will disregard that possibility. The cold air displayed by the large blue arrows represents the cold air moving southward.
Here is the next major shot at some very cold air, not saying that it won't be cold in between, but guys, if this isn't the biggest GFS troll I have EVER seen...that big snowstorm misses us due to one unfortunate factor, blocking on the western side of moisture return. This will change, remember that. But there could have been some fun GFS stuff to look at on the 18z if it had pulled through for us. What happened here is that the Jet Stream and Subtropical Jet come close enough to block each other, but separate JUST ENOUGH to get moisture in the southeast/Ohio Valley and spark a very decent snowstorm. This is ALSO about the time a storm system has been initiated over the past several runs, so this will indeed be monitored, because a storm system is beginning to be forecast to spawn and create snow in between the 13th and 15th, and the pattern becomes more conducive to bigger snow down here during that time frame, so will definitely continue monitoring. Biggest thing to remember, this, WILL, change. Southeast Arkansas could see some flurries out of that run though. We will see what the 0z has for us.
The last thing that will be covered is the lower levels. 850 millibars is what we will be looking at, this is some ways into the lower atmosphere.
This is the lower atmosphere, this is one of the things that factor into whether you get snow/ice/mix/or just rain. This is ahead of the first cold front, temperatures (running in degrees C) are well above 32, and the red rectangle is where precipitation is, meaning that temperatures in the lower atmosphere hit 32 or lower AFTER precipitation has ended. I will see what this does in the 0z data, but right now precip ends before any kind of changeover can happen.
Onwards to the CMC, one of the leaders for cold air. Also to save time, I will only cover the first cold shot with the other models.
The CMC has a similar solution with an amplifying jet stream, it has precipitation ending before the upper/lower levels & surface can cool off.
Here is the lower atmosphere with the CMC, it has cold air moving in at the lower levels, but AFTER precipitation has ended here, therefore this run shows no potential of wintry precip at this time.
The Euro model is just as strong with the cold air after the front next week. It has the 540 line moving all the way down to the Gulf of Mexico. I can not show the European model through graphics until I figure something out, but the 12z euro says that light snow is possible across northwest Arkansas next Wednesday-Thursday as the front passes and some leftover moisture sits in the cold air. This will still be monitored as things will change.
The NAV, or the Navy model, has the same set up with an amplifying jet stream and a strong cold front with plenty of moisture along it.
This is what the Navy model has for the cold front, it has a deep dip in the jet stream, and some light snow in NE Arkansas, it appears green because the model doesn't show frozen precipitation. This is likely overdone though because of the amount of moisture precip. I will not disregard it though, temperatures dive below freezing behind the front.
Last but not least, the JMA (Japanese) Model
The JMA model is one of those models that I don't use in blogs really, because it's an oddish kind of model for me to use. The JMA model doesn't have too many options like surface temperatures or anything, so I have to use the lower atmosphere, 700 millibars is a bit higher but still the lower atmosphere. (700 millibar) temperatures. Judging by this, they are well below freezing and can safely assume that surface temperatures are below freezing a good deal. Remember guys, all of this can and WILL change.
This is the end of the 18z data tonight. Will continue the blog on the 0z data.
0z data continuation
Well.....the two models that will be mentioned here are the GFS and CMC. The GFS....hm....
Now, take this with a BIGG grain of salt, because this is still long range, but this IS the operational run so will be paying more attention. There really were no differences with the short term in either model, good agreement, but here's something I wanted to point out with the data. So this is the GFS right? (By the way, this will change MANY times and just for fun, another system to the NW of this one moves in and stalls with snow over the state, just something fun to mention but it WILL change. Don't get hooked)
I'm gonna compare the last run to this one.
This was the last GFS run, drastic changes, so it is still incredibly low confidence. We'll keep you guys updated!
Well, that is it for this, fairly long blog, I hope you guys enjoyed and have a good rest of the night and good Saturday! I will be back with another blog later.
~Michael, "Zonal Pattern and Late next week" Pictures provided by Jason. Rest of the maps courtesy of TropicalTidbits