2/28 - 10pm - Snow Showers Possible in MS This Weekend

As cooler air filters in overnight we'll see chilly temperatures tomorrow morning in Starkville along with cloudy skies. A disturbance rotating through the backside of a large low pressure area over the Eastern US will give us a shot at some flurries and snow showers late Friday night into the morning on Saturday. Just like a couple weekends ago, there could be some flurries flying at the MSU baseball game on Saturday afternoon. Temperatures will begin to warm a bit on Sunday and eventually we'll get all the way into the 60's for the new workweek. Your full Mississippi State CampusConnect forecast is in the video below!

1/31 - 11:15pm - Snowy to Our North, but Clear Here!

An Alberta Clipper system moving through the Lower Ohio Valley is spreading snow all the way down to I-40 in Tennessee this evening. Those of you in Starkville hoping we might get some flakes tonight will be disappointed to know that this system is running out of steam over the Jackson, TN area and will have trouble even generating any clouds for us this evening. Behind the cold front associated with this Clipper is some cooler air that will be working in overnight. This means we'll get down into the mid 20's by morning in the Golden Triangle and only reach into the lower 40's for highs tomorrow. Ouch! Luckily we'll have full sunshine as we end the workweek but a few showers are poised to move through the area for the early half of Saturday. Check out the video below for your detailed CampusConnect forecast!

12/30 - 8pm - Anyone Up for a Third Round of Wintry Weather?

With two winter weather events within a week's time in the books for Kentuckiana, it's apparently time for a third! Unfortunately the timing for this one is pretty bad. Just as folks are going home from New Year's parties in the early hours of Tuesday morning we could have snow, sleet, or even freezing rain falling in the region. The good news here is that regardless of what falls from the sky, there won't be much of it. Precipitation amounts will remain light since heavy rain and storms in the South will be stealing our moisture here up north in Kentucky and Indiana during the time of the event. As far as timing goes, a few snow showers will move through tomorrow afternoon as this system begins to move toward us. Going into the evening is when things get tricky.

As a weak area of low pressure continues to approach we'll see some warming aloft out ahead of it. This warming has the potential to turn our falling snow into sleet or even freezing rain. The GFS is leading the charge at the moment on the potential for freezing rain in Louisville as it has a layer above freezing from 4,000 to 7,000 feet at 4am on Tuesday morning that would support freezing rain. The NAM model keeps us all snow with the entire atmosphere being below freezing. Given that the models have overestimated temperatures aloft with the past two snowstorms we've seen lately, I'm inclined to think that Louisville will stay mostly or all snow. Another thing to focus on will be surface temperatures. Should they be just below freezing this snow, sleet, or freezing rain will stick to the roads and make for tricky travel on late Monday night. If they're just above freezing then only expect to see accumulation on the grass and elevated surfaces. We do have a bit of snowcover in Louisville now, so that might lean us more in the direction of below freezing instead of above for this event overnight Monday into Tuesday. We're going to be awfully close to freezing for much of the night regardless. Areas north of the city will likely stay all snow and below freezing while those areas to the south will see a wintry mix and temperatures just above freezing until the early morning hours. National Weather Service offices across the Plains have issued Winter Weather Advisories due to this system, in purple on the image to the left, but uncertainty about precipitation type and amounts in the Ohio Valley has NWS Louisville waiting for more agreement before they issue any advisories.

Like I said before, accumulations are going to be light for this event. The NAM (right) has up to an inch of snow in many areas and the GFS model has been a little more optimistic at times today with 1-3" across the area. Like the last two snow events, I'm thinking that the amount of precipitation being put out on the models will adjust upward a bit as we get closer to time (tonight and tomorrow morning). Given the trends I'm seeing right now I think we'll see 1-2" of snow in portions of Louisville and points northward with up to an inch of snow and mixed precipitation to the south. Once again... grumble grumble grumble... Louisville is right on the line between feast and famine with the snow. Southern Indiana has been the big winner with snow over the past week while folks south of the Ohio River are raising their hands in favor of more. That is, if you're a snow lover of course. So, we'll be looking to see over the next few hours how the models handle the amount of precipitation forecast, and temperatures both aloft and at the surface. Shifts in these could mean some significant changes to the forecast for many areas!

12/28 - 1:30am EST - Kentuckiana Winter Storm Number 2

Wednesday's winter storm didn't give much snow to folks in the Louisville area and instead confined heavy snow to areas of Southern Indiana. While differences in the models did exist over whether Louisville would get any accumulating snow or not, the overall situation was handled pretty well from a forecast standpoint. The highest snow report in NWS Louisville's coverage area was 7.2 inches in Washington County, IN while Louisville received a trace to a half inch.

The next storm on the heels of the last one is less than 24 hours away as a system arrives from the southwest and stays to our southeast as it moves through the region. This will start as some rain for the Louisville area but as colder air filters in we'll switch over to snow during the later evening hours. This exact time for switchover depends on how warm we get during the day tomorrow (lower 40's versus upper 30's makes a difference!) and how fast the cold air comes in. The 0z NAM that came in earlier tonight has about 3" for the city and after comparing this with other models I'm thinking this may be a number we'll see most commonly reported by Saturday morning in Louisville. Higher totals will be possible just a bit further north from Louisville.

But even as I say this there's a small fly in the ointment. The 3z RPM model is in and it has the possibility of 4-6" of snow just due east of the city and a few very small totals like this scattered throughout areas near the Ohio River. This suggests that totals closer to 4" might be more widespread than previously thought. You can click the RPM output on the left for a larger view. We've seen the trend of increasing snow totals today on the models and this run of the RPM just continues this. We'll need to watch for this trend tomorrow morning to see if other models catch on. Right now this isn't really a factor in my forecast since it's just one model. Below is my snow forecast map for the region. Realize that, like the last storm, a small shift in track or more/less cold air will change things for some folks drastically.

Also worth noting is that the Hyrdrometeorological Prediction Center (HPC) has us in a Slight Risk of a 4" snowfall (think of this like the Slight, Moderate, and High severe weather risks) while areas closer to Cincinnati are in a Moderate Risk. Expect to see Winter Weather Advisories being issued tomorrow for portions of Kentuckiana. There may also be a few Winter Storm Watches issued as well depending on if forecast amounts of 4" or more look to be more widespread. You can keep up with the latest on this storm tomorrow by following me on Twitter and Facebook. Good luck, snow lovers!

12/21 - 2pm - I'm Dreaming of a White (Day After) Christmas

How about that snow last night around Kentuckiana? Most places saw a dusting but areas in Southern Indiana near Orange County picked up about 3 inches since a snow band set up there for a few hours during the overnight. Here at my house in Southeast Louisville we picked up a dusting of snow that blew around a bit in the wind. Temperatures today aren't going to make it out of the mid 30's in Louisville today thanks to the cold air behind the front that passed through yesterday. Seems appropriate given that it's the first day of winter!

Temperatures will moderate for the weekend with southerly flow returning but an area of low pressure moving through will bring rain and even warmer temperatures for Christmas Eve. Booooo! Luckily Christmas Day isn't looking like a washout with just a few clouds and highs in the lower 40's. That's a different story further South in Mississippi, Alabama, and Georgia where rain will be setting up.

Now... onto the fun part. Over the past couple of days the forecast models have been jumping onto the idea of an area of low pressure moving from the Gulf states to the western side of the Appalachian Mountains the day after Christmas. This is concerning because this track favors a snow event for Kentuckiana and even some of West Tennessee. You need to be on the north and west side of these low pressure systems if you want to see some snow since that's where the cold air is confined to. The past few systems we've been on the south and east sides of the lows moving though so that has meant thunderstorms and warm weather lately.

The latest 3 runs of the GFS for this particular post-Christmas storm have been fairly consistent with the low track, which is good! The problem has been that there's been trouble determining how much cold air there will be to work with and how strong/large the low moving through will be. These issues have affected how much snow the Louisville area gets. The graphic on the left is a comparison of the last 3 runs of the GFS for December 26th. For entertainment purposes only, the 0z run had just shy of 8" of snow for Louisville, the 6z had about 3", and the 12z had around 2.5". It is still way, way too far out for specific totals and to worry about the cold air issues yet since things will change likely on the models between now and then. I will say though that the 6 and 12z runs seemed to have difficulty keeping the low as a single, compact system once it matured and instead wanted to go with an elongated large low that tries to interact with another low that develops east of the Appalachians. I've seen this kind of thing happen on the GFS earlier this year with the Nor'easters that we had. Eventually, based on what happened with these Nor'easters, these elongated lows should give way to more concentrated, compact lows on the GFS as we get closer to the actual event. This should help to clear up some of the murkiness with the cold air issues too.

The Euro has been fairly consistent with the track of the low as the GFS has been, but has also experienced a few issues of its own like the GFS. Yesterday's 12z run of the Euro had a blockbuster snow event in the Louisville area while the 0z last night backed off on that prospect thanks to, you guessed it, a more elongated low and trouble with cold air. I can't post the precipitation output from the Euro model since it's behind a paywall and copyrighted, but I can at least show you what the 0z run did with the low after it moved through. Lots and lots of cold air will be behind this system if you couldn't tell by the deep blues and purples on the map!

UPDATE 2:20pm - Today's 12z Euro model run is in and it has a blockbuster storm track for snow for us here in Kentuckiana and West Tennessee. That is quite a strong low in East Tennessee on the left-hand map compared to previous runs. Sheesh.

The CMC and the JMA, which are the Canadian and Japanese models, aren't worth showing here right now. The CMC has the storm running off the east coast and the JMA has a nice low track for some snow in Louisville. It's worth noting that this system might disappear all together on the models or make a radical change. It's still too far out for much certainty.

Also, West Tennessee may see snow from this storm should it take the track that we're seeing. It wouldn't be much snow but certainly more than an inch or so isn't out of the realm of possibility, especially in Northwest Tennessee. Once we get closer to time this will become a bit more clear.

The NAO, which is the North Atlantic Oscillation, frankly isn't agreeing that there will be support for this storm. A negative NAO means blocking near Greenland allows for cold air to flow into the Eastern US and stay locked in place. The current forecast is for a positive NAO during this time, but it has been flipping between negative and positive over the past couple of days. This storm doesn't have to have a negative NAO to happen, but it would help to have it for cold air support and for a storm track that rolls up to the northeast. This will, like the aforementioned models, sort itself out over the next few days.

 

Finally, NWS Louisville has been on board with this storm since yesterday. They're being cautious like they should be but mentioning at length the potential for this at 5 days out is something that they don't do very often. Here's their latest statement:

A much more significant weather system will arrive on the 26th. Both the 00z GFS/ECM and ensembles track a strong low pressure system just to the west of the Appalachian spine which may set us up for our first significant snow. If the low pressure system takes its current forecast track, precipitation would enter the area Wed morning with the bulk of precip occurring Wed during the day and then exiting late Wed night or Thurs morning.

Although there is still much uncertainty in the track of this weather system 6 days out, the possibility is there for significant snow based on the low track and anticipated thermal profiles. BUFKIT GFS showed 8 inches at SDF with a little more than 0.5 inch of qpf. The soundings denote a classic heavy snow sounding with subzero and deep isothermal layer super saturated. The synoptic features of interest are a 110 kt jet max entering a the base of a deepening trough.

For now will have 60% pops on the 26th with rain in the morning and then snow in the afternoon and Wed night. Bing Crosby`s I`m dreaming of a White Christmas may happen, just 24 hours later.

Stay tuned for upcoming forecast updates as this weather system may put a kink in holiday travel plans.

 

This will be a fun system to watch over the weekend. Hopefully there's some snow in our future!

 

12/11 - 10:30pm - Be Careful When Wishing for Snow... You Might Get it!

With all the warmth much of the eastern portion of the nation has been experiencing lately some folks are beginning to get antsy over whether we'll be able to fall into a more winter-like pattern in time for the holidays. The cold front that rolled through earlier this week has helped to assuage some of those fears as it brought much cooler temperatures and even some light snow/sleet to parts of Kentucky and Indiana.

So... What's next? First up is a system that will move through the region this weekend as a warm one. A low will travel from the Plains to Lake Michigan and keep the eastern half of the nation warm as it spreads rain from the Great Lakes to the South. This makes sense because the North Atlantic Oscillation (NAO) will be going neutral during this time, which generally means that cold air won't be able to spill down into the Eastern US from Canada. The Arctic Oscillation will be negative to support cold air coming out of the north, but that doesn't matter too much for us when the NAO isn't negative as well.

The system behind this weekend's is the one that is drawing some concern. A low will be moving across the South during the day on Tuesday and potentially spread some snow to areas that are north of it. At this point anywhere from West Tennessee to the Louisville area is in a potential corridor for snow. This all depends on the exact track of the low and how much cold air it will be able to bring down from the north. This scenario is supported by the NAO and AO both going negative during this time. The GFS model takes the storm along the southern border of Tennessee right to the Carolinas. The ECMWF (European) model starts out with the low a little further south along the Mississippi River but has it exit off the coast in about the same location as the GFS. The low would then become a storm that would ride up to the Northeast just off the coast. With the previous system pulling up toward the Chicago area, this low will likely stay suppressed to the south. So... the broad, general nature of this low's track isn't in too much question. My preliminary (read: subject to change!) thinking is that this will be a rain to light snow situation for portions of Tennessee and Kentucky since cold air would plunge in as the system is exiting to the east. Accumulations would be very light to none.

But here's an issue. The snow cover over the Northern Plains and Upper Midwest has expanded tremendously over the past week as a storm pummeled those areas with quite a bit of snow. We're now at 31.4% snow cover over the United States. Air moving from the north over that snow won't warm as quickly as it would over bare land and the computer models generally have a difficult time resolving that. With this snow cover, the air in place over us and the air coming down from the north may be a little cooler than the computer models think it will be at the moment. That could mean more snow from this system. We're still a week away from this event so while details are sketchy, it's now obvious that this is a system to watch. This likely won't be the only storm we'll have to contend with between now and the new year since a pattern is setting up that will allow cold air to sit close by to the Ohio and Tennessee Valleys while lows track through and just to the south of the region. There's hope for a white Christmas in the region but it will depend on whether we can get enough cold air and a storm to move through just before the 25th. It'll be fun to watch!

10/29 - 3:30pm - Superstorm Sandy Coming in, Cool Week in Mississippi

Hurricane Sandy is a monster storm. That goes without saying. It's about two hours from landfall as of this writing but that won't matter much due to just how incredibly large the wind field is. Tropical storm winds extend for hundreds of miles from the center of the storm making this the largest hurricane ever recorded in the Atlantic Ocean at over 1,000 miles wide. This is big by area, not by wind speed. While the winds extend for an incredible area the winds in general are at Category 1 speeds near 90 mph. For areas in the tropics this may not sound so bad but for the Northeast this is a disaster since winds rarely get up to that strength with storms up there.

Something that also may be unprecedented here is the extreme snow threat from Sandy for the mountainous regions of West Virginia, Virginia, North Carolina, Tennessee, and Kentucky. Snow totals could be 1 to 2 feet in places when this storm is said and done. The other thing to consider with the size and scope of this storm is the storm surge that continues to roll in. Places like New York City and along the Jersey shore could be dealing with storm surge totals in excess of 11 feet thanks to the pure mass of water that will be coming in with the storm. This will create coastal flooding whereas the high rain totals will contribute to inland flooding. You'll hear about this storm for years to come... 765,000 customers are without power across the Northeast already and this storm is just cranking up.

How is this storm affecting us here in North Mississippi? We're just seeing cooler weather thanks to the large trough of cold air that's in place. This trough is the same one that's ingesting Sandy making it a very unique storm and pulling it into the Northeast. This cooler air is going to be sticking around for the foreseeable future but with some moderation. Highs won't get out of the lower 60's tomorrow and we'll finally break into the upper 60's on Wednesday for Halloween. Overnight lows tonight will be of concern since they'll be getting close to freezing, which will create a chance for some frost. Your complete Starkville forecast with these details and more are available in the video below!

10/27 - 5pm - Quiet in West Tennessee, Sandy Takes Aim

Ready for a REAL taste of fall? It's here.... and It's going to stick around for quite awhile. A large mass of cool air continues to work its way into West Tennessee this morning behind yesterday's cold front. That means temperatures today will be getting into the upper 50's across the region. By the time we get to late tonight and early tomorrow morning we'll be talking about mid to upper 30's for lows. Bundle up! High pressure will keep this cooler air locked in place through the week and sunshine will be plentiful as it has been in most places today. We'll need to watch for some frost in areas during the mornings starting on Monday as temperatures fall to near freezing overnight. High temperatures will slowly work their way to near 70 degrees by the end of the workweek.

Let's talk about Hurricane Sandy. It's a weak hurricane right now but the setup is more complicated than just that. As it moves toward the Northeast it will merge with a trough moving across the eastern half of the nation. This will transition the storm from a hurricane to what's called an extratropical storm. Basically this means that the storm won't feed off of warm water like a tropical system would. This will turn Sandy into the very, very large storm that its already beginning to become. Threats for wind damage, storm surge, and flooding will be possible for a broad swath of the Delmarva Peninsula through New England. New York City, Philadelphia, and Washington DC are included in this among many other locations. The storm surge issues will be amplified by the size of the storm, which moves more mass of water, and by the fact that this will be happening during a full moon, which maximizes tide. Check out the tropical storm force wind probabilities to the right... this is pretty significant when you consider there's a 60-70% of sustained tropical storm winds from Delaware to Long Island.

Another threat this storm poses is snow. West Virginia with its higher elevations will bear the brunt of the snow with 1 to 2 feet expected in areas. The latest run of the GFS model paints a very large area of 18"+ snowfall amounts through Tuesday evening. This could be crippling because there are still leaves on the trees that this heavy, wet snow will weigh down on snap limbs. Mass power outages are very likely whether you're in the wind/rain area in the Northeast or in the snow area in West Virginia.

In the video below you'll get a full dose of information on Hurricane Sandy and your latest West Tennessee forecast.

2/18 - 2pm - Somewhat of a Snowy Fizzle

Last night's model runs were coming in very bullish for snow in West Tennessee on Sunday morning and I was even putting together a graphic very early this morning that had 2-4" of snow in Northwest Tennessee. As the 6z model runs came in there was a pretty stark change in the forecast all because of one fact: two waves in the upper atmosphere were not phasing (or joining forces) as quickly as previously predicted. This means that the cold air from the northerly wave will not inject itself into the southerly one until it reaches Nashville. Without this cold upper-air support, the chance for snow dwindles considerably.

While some light accumulations are possible in Northwest Tennessee tomorrow morning, much of the region should remain plain rain with some mixed in snowflakes. A brief burst of snow may happen later on Sunday morning as this system pulls out of the area, but even in areas with accumulation it should not cause problems on the roads due to above freezing surface temperatures. Areas north and east of Nashville, however, will see the accumulating snow and some of it could be on the heavy side.

Once the rain and snow is gone later on tomorrow morning we should be left with cloudy skies and cooler temperatures in the 40's across West Tennessee. There are a couple rain chances thrown in next week on Tuesday and Wednesday, but the rest of the week should be relatively warm and dry. Check out the video below for your complete forecast (Note: I left my TV tuner for my laptop in Mississippi so I don't have a longer copy of this video):

2/11 - 5pm - A Wintry West Tennessee Forecast

A front that passed through West Tennessee last night brought rain showers during the overnight hours and snow showers this morning across the region. These have since moved out of the area, but the snow came down in some heavy bursts at times even though there was really no accumulation. High pressure will provide the setup for a very cold couple of days with highs in the 30's and overnight lows in the teens. Yikes! Tonight could be the coldest night of 2012 so far, which really isn't saying much since we've been pretty mild as of late.

Monday's forecast is flat-out complicated. Warm air overriding the retreating arctic air mass in place from this weekend will set the stage for a storm that could put down snow, sleet, and even freezing rain. Most indications are that this will start off as snow across most of West Tennessee on Monday afternoon as the lower layers of the atmosphere moisten up, but this snow could switch over to a period of wintry mix later on in the evening as the atmosphere warms up more (notice the warm "push" at 850 mb - 5000 ft on the left). Once we reach a certain threshold of warming on Monday night into the wee hours of Tuesday morning, all the snow, sleet, and freezing rain should transition to plain rain and the wintry weather headaches will be no more. Before everything switches over to rain an inch or so of snow could be on the ground around the I-40 corridor, including Jackson, according to the latest forecast models. Areas in Northwest Tennessee will switchover to rain a little later on than I-40, so there may be up to two inches on the ground. This is nowhere near set in stone yet and I'm willing to bet we'll see a few small changes in this forecast before the weekend is over.

The models agree that snow will fall across West Tennessee on Monday, but there are differences in when exactly this warm layer aloft will come in enough to switch the snow and wintry mix over to rain. The 18z NAM seems the most conservative on snow amounts at this point, with only a half inch in Jackson on Monday night. It also suggests that we might avoid a wintry mix and switch immediately over to rain. There's even a brief shot of rain just before the snow starts on that model. The GFS is bullish on snow amounts with over an inch in Jackson with the aforementioned wintry mix period (depicted as freezing rain on the BUFKIT output to the right) before the switchover to rain. The main issues seem are the timing of the warm air intrusion aloft and how strong it will be. So while this won't be a huge winter weather event by any stretch of the imagination, a few travel issues may crop up on Monday evening as the snow and wintry mix is falling.

Check out the video below from this morning's newscast on WBBJ for more details on your forecast!

1/14 - 10pm - All Sorts of Interesting Weather Today!

Henderson County, TN

The Wind Advisory that was in place for southwestern portions of Tennessee today was canceled at noon because wind speeds across the region were falling just below the 25 mph necessary. Nevertheless it was quite breezy and today's high in Jackson got up to 54 degrees, well above what was expected. Some clouds from the Alberta Clipper system (explained below) did make it into the region and I even managed to find some mammatus clouds, which are pictured on the right, in Henderson County, TN this morning. You usually find these underneath a springtime thunderstorm, but in this instance I think they may have been caused by snow hitting the layer of dry air in place underneath the clouds. Aside from the oddities of today's weather, the new week looks warm until Tuesday when showers and storms will give way to another cold snap and again another gradual warm up. Check out my forecast on WBBJ this morning (my first one in 2012!) below for more details:

What is an Alberta Clipper? Put simply it's a fast-moving area of low pressure that dives southward from the area near Alberta, Canada in the wintertime and spreads light snow to the Midwestern states. This particular Clipper was an interesting one because it centered its maximum snowfall in a very small area as the storm moved through Kentucky and Tennessee. More specifically, this area was just south of Louisville from Harrison County, Indiana to just south of Lexington, KY. Accumulations vary widely in Louisville because of the scattered nature of the snow bands that moved through, but they seem to range between a half inch to around two inches. South of town there are reports of more than three inches around Bardstown and Taylorsville! NWS Louisville's forecast graphic from earlier this evening points out pretty well where the most snow has fallen and you can tell exactly where the heavy snow band sat this afternoon. I drove through this band near Radcliff, KY on my way from Jackson, TN to Louisville and I can verify that it was indeed very heavy as indicated on the map. I took a quick video of today's snow at my house in Southeast Louisville just as I got home for my long weekend:

1/12 - 6pm - Another Cold/Warm Roller Coaster

Cold air is filtering into West Tennessee and North Mississippi as a cold front that came through earlier this morning continues to move east. Snow showers fell as far south as portions of North Mississippi this afternoon, but the bigger snows from this system were confined further north into Missouri, Illinois, Kentucky, Indiana and the Great Lakes. Check out this picture below that my sister sent me of the scene this afternoon at my house in Louisville, KY: 

Even though only an inch or so will be on the ground by later tonight, the gusty winds of 20 mph+ could create blowing snow conditions with low visibility.

You'll feel the cold air behind the front tonight for sure if you're out and about. By early tomorrow morning temperatures across West Tennessee could be in the lower 20's and upper teens while North Mississippi will bottom out in the lower 20's. Highs tomorrow will range from the upper 30's in West Tennessee to the mid 40's further south in Mississippi.

That's about it for the cold though. Not long at all, right? Warmer weather will begin moving in for the weekend and early next week a ridge builds into the eastern half of the nation. Temperatures will likely get near 60 early next week before another system brings rain on Monday night and cooler temperatures for the middle of next week. The roller coaster continues!

12/26 - 12:30pm - Post-Christmas Snow Chance?

While many did not have a white Christmas yesterday, it certainly was a nice day across much of the East US with warm temperatures. We now turn our attention to a system that will be bringing much of the Southeast rain and possibly some snow as you head northward. This system is brewing in the Gulf Coast states right now and will bring West Tennessee rain this afternoon through tomorrow and the Louisville area rain tonight through tomorrow. While West Tennessee will likely stay all rain throughout the duration of this system due to warmer temperatures, Kentuckiana may have to deal with some snowfall during the afternoon tomorrow. The track of this storm from Tennessee to Eastern Kentucky is usually one that gives us our bigger snow events during the winter, but this time that won't be the case because of the lack of cold air we'll have to work with.

The forecast for snow is a tough one because we'll be dealing with colder air coming in on the backside of this system to give us our snow. This means that the atmosphere will cool from top to bottom and while snow will be falling it will likely not accumulate much, if any, because the air at the surface will still be warm while the upper atmosphere cools down. Nevertheless, a switchover to snow in the Louisville area will likely happen sometime tomorrow during the early to mid afternoon hours as cold air penetrates enough of the atmosphere to keep snow falling all the way to the surface. The NAM (left) seems to be the most aggressive on this switchover right now due to the surge of cold air it brings in early on in the afternoon in Louisville but the forecast sounding, or a vertical snapshot of the atmosphere at a given time, still indicates that we'll have temperatures just above freezing near the surface. This means that snow will be making it to the ground, but will likely melt on contact or accumulate lightly on the grass and elevated areas in heavier snow bands. Speaking of banding, that's another issue we could face. Snow banding is when you get a thin strips of heavy snow falling that look like bands due to winds coming together in these areas. These bands can produce snow accumulations even when temperatures are above freezing, just like in Jackson, Tennessee earlier this month when over an inch of snow accumulated with temperatures just above freezing.

Overall, I think areas in and close to Louisville can expect a dusting and maybe up to an inch of snow on grassy and elevated surfaces at some point tomorrow evening. If cooler air does not come in as quickly as expected this will remain a rain/snow mix or even just plain rain. Areas north and west of the Ohio River have the best shot for a light accumulating snow as they'll be slightly cooler and have an earlier switchover during the late morning hours. Most of the models are agreeing that we'll stay above freezing during most of this event, but we will be dipping down below that mark late Tuesday evening. This may create slick spots if any roads are wet from the snowfall during the afternoon. The 12z NAM (top left) is indeed the most aggressive on snowfall totals around here by looking at the snowfall output map, which you can see a larger view of by clicking. The 0z GFS (bottom left) is less aggressive, which is typical for it lately, and the Euro (which I cannot post here to copyright policies) keeps the snowfall along and north of the Ohio River. There are still a lot of small variables like exactly how fast the precipitation will move out of here and how much cold air will actually work into this process, so little details like these can drastically alter who gets snow and how much.

12/12 - 7pm - A Few Bits About Snow

While things have since quieted down snow-wise, it has been a very snowy start to the season in West Tennessee. Jackson, TN has had 3.3 inches of snow so far this season, which is an astounding figure given that only about 0.1 inches falls on average by this time of year. This total beats out the season totals in many northern cities, some of which are known for their heavy snowfall including Buffalo, New York and Bismarck, North Dakota. Check out the graphic on the left to see a full list of some of the cities that Jackson is beating out. The rain to snow chance on the 21st isn't showing up on the models right now because they're dissolving the upper-level low before it makes it past NW Arkansas, but it's something to keep an eye on. A few flakes may fly further north near Louisville, but even that's not going to be a big deal according to the models. Another system packing precipitation and cold air may try to roll through a couple days before Christmas too, but that's way to far down the road to make guesses for any location at this point.

Speaking of snow, did you know that the Grand Canyon in Arizona gets more snow than Minneapolis, Minnesota? It's true! You may think of Arizona as a dry and hot state, but the higher elevations in the northern regions near Flagstaff get quite a bit of snow. Grand Canyon Village, AZ at the top of the canyon is expected to get 4 to 10 inches of snow by Wednesday morning while Flagstaff could get 12 to 16 inches. These areas are under a Winter Weather Advisory and Winter Storm Warning respectively.

11/30 - 4pm - Mid-South Winter Storm Wrap-Up

The National Weather Service in Memphis has released a snowfall map that recaps the measured snowfall totals across the Mid-South. Jackson, TN broke an all-time November snowfall record with 2.0", but note that slightly higher totals were recorded elsewhere in Madison County away from where the official observations are taken for the NWS. Look at those snowfall accumulations of over 5" in Northeast Arkansas and the Missouri Bootheel... very impressive! This was quite a rare storm and the method through which the storm produced the snow, a cut-off low that supplied its own cold air from aloft, is something that doesn't happen too often either.

The snow was even apparent on visible satellite this morning, which is amazing because temperatures were above freezing for most of yesterday:

Wintry weather should stay out of the forecast for at least the next week or so, but rain chances will be on the increase in West Tennessee early next week. The GFS computer model is hinting at the possibility of a little bit of snow late next weekend, but it's much too far out to make any predictions at this point. Certainly something to watch!