A little rain and snow overnight, with a bigger winter storm possible early next week

The Atlanta metro area will see some rain and wet snowflakes during the early morning hours of Friday, January 21, 2011. There may be a dusting of snow in some areas by sunrise – a rather rude reminder for the folks of Atlanta that winter is far from over. Be careful as you drive to work or school Friday morning as there could be a few icy areas, especially on bridges and overpasses.

A more significant winter storm has its sights set on the Southeast region, including Atlanta for next Monday, January 24 and Tuesday, January 25, 2011. It is still way to early to talk specifics or even show any serious confidence that this storm will happen, but it is definitely on the forecast models in varying degrees of severity, so it needs to be mentioned. As it stands right now for Atlanta, it looks like precipitation could start as snow, then transition quickly to freezing rain, and then possibly to rain as the system moves out. Precipitation totals look to fall within the light to moderate range, but when dealing with freezing rain even light amounts can cause serious travel issues. So, just a heads-up at this point to watch the weather forecast closely for next Monday and Tuesday. I should have a much better handle on the specifics of this system by the weekend, and I will post further thoughts then.

Late Season Winter Storm for Dixie

A late season winter storm is taking aim on parts of the Deep South.

Low pressure will roll eastward out of New Mexico & Texas on Monday tracking across the northern Gulf of Mexico, or just inland along the Gulf Coast states on Monday night and Tuesday. Meanwhile, some upper level energy from the northern branch of the jet stream will phase with this system, and give it a shot in the arm as it impacts areas from Alabama to Georgia and into South and North Carolina.

Temperatures are only going to be marginally supportive of snow, and really this could go either way fro areas of Alabama and Georgia. It’s either going to mostly all rain with maybe a brief changeover to snow for a few hours at the end of the event. Or, it’s going to be rain changing to a wet, heavy snow with large snowflakes falling steadily for at least 6 hours and accumulating to several inches. Unfortunately, we probably won’t know exactly how this is going to hash out until the actual event is unfolding on Monday night and Tuesday.

So, as of this time on the Sunday morning prior to the event I am not willing to put out an official forecast, so here is my unofficial thinking: 2 inches for Atlanta, GA, and 1 inch for Birmingham, AL. Mt. Cheaha, the highest elevation in Alabama could pick up 3 inches, and the east and northeast metro of Atlanta could see 3 inches, with maybe some isolated 4 inch amounts.

I’ll give my official thoughts on this system by 11pm EST on Sunday.

Severe Storms in Central Georgia Today, and Heavy Snow Possible Sunday. I’ll be Storm Chasing Today and Sunday.

STORM CHASE STATUS: ACTIVE

TARGET: Central and southwest Georgia and southeast Alabama.  Macon, GA to Columbus GA to Troy, AL to Panama City, FL to Valdosta, GA to Macon, GA.

TIME: Depart Atlanta at 11:30am EST.  Arrive in target by 1pm.  Actively storm chasing until approx. 9pm.

LIVE INTERNET BROADCAST: 11:30am – 3pm at http://www.ustream.tv/channel/mike-phelps-mobile-weather-stream (live video and audio) 3pm-9pm EST at http://www.severestudios.com/livechase.  Chasing as Mike Phelps.  Live video only.

AVAILABLE FOR LIVE PHONE INTERVIEWS: 2pm – 9pm EST via mobile phone at 404-202-6317.  Leave message on voice mail and I’ll call right back.

DISCUSSION: A warm front stretches west to east across central Georgia this morning.  This front should remain in this general area through the afternoon and will provide a corridor of increased low level helicity that could be a breeding ground for a few tornadoes.  I don’t think we will want to stray too far south of that warm front today.  Dewpoints in the mid 60s have moved into south-central Alabama this morning, and will continue to spread across southeast AL and into portions of southwest GA and the western FL panhandle this afternoon.  All models indicate a broken line of supercells developing along and ahead of an advancing cold front from central GA into south-central AL after about 3pm today.  These storms will have the potential to produce large hail and damaging winds, and in that corridor of higher helicity near the warm front there will be a threat for isolated tornadoes.  There is a CAPE and EHI max that has been showing up now on a few runs of the NAM so I believe what we will do is head southwest from ATL on I-85 and establish a base of storm chase operations in Columbus for a while and then adjust locations from there.

WINTER STORM DISCUSSION: Forecast models remain consistent in showing an upper level low snow event across parts of the Southeast starting later today in the Mid-South and spreading south and eastward across Dixie tonight through Sunday.  This is a very dynamic system with good moisture associated with it, and the potential certainly exists for some heavy snow.  The last couple of runs of the NAM have taken the upper low on more of a southerly route over what it was showing this time yesterday, although the 06z NAM shifted north again.  If this track comes to fruition then a swath of significant snow (3+ inches)  will extend from Memphis, TN to Birmingham, AL Atlanta, GA to Greenville, SC and northeast from there.  It is very difficult to pin down the exact location of the heavy snow in these upper level low snow events this time of year, so who is to say that the area I outlined above will ultimately verify, but we are gaining more and more of a consensus among the models that this track of significant snow is becoming more likely.  In my opinion, there is still the potential for this system to produce some “jackpot snows” on the order of 5 to 10 inches, but it remains impossible to pin down the location for that.  I want to strongly caution that certainly nothing is set in stone with this system as of yet.  There is still a rather sizeable potential that it will end up being far less of a big deal than a lot are anticipating.  Keep in mind that snow outside of the state of North Carolina and the mountains of Tennessee, has been basically non-existent this winter.  La Nina winters simply do not breed big snows outside of those areas.  Also, the forecast models have been less than stellar in their performance this winter.  Honestly, we are not going to feel real confident about any snow forecast with this thing until it is actually happening.  So, watch the system closely, but don’t be quick to jump onto any snow or non-snow bandwagons until the wagon is actually passing through your area.

If this system produces significant snow near Atlanta, GA on Sunday then I will be broadcasting it live on the internet.  I’ll have details about this live broadcast in my Sunday morning blog.

An Wild Weather Weekend for the Southeast with Severe Weather and Significant Snow Likely!

All systems are still go for severe thunderstorms, then snow across parts of the Southeast this weekend, and we are now getting into a range where I can throw out some more specific forecasts with some measure of confidence.

First, I’ll discuss the severe weather prospects for Saturday and my plans to chase the storms and do a live internet broadcast of my storm chase.

It is hard at this point to say exactly where the greatest threat for severe storms will be on Saturday.  The models are pretty much showing the area in Georgia and eastern Alabama along and south of I-20 as being in the threat zone.  However, I’m not sure the models are handling the effects of the large convective system over central AL and GA very well.  Surely this will reinforce the boundary farther south than the models indicate.  Right now, I’m thinking along and south of  line from Macon, GA to Troy, AL will be my target for severe weather on Saturday.

Steep lapse rates, rather low freezing levels, and the potential for rotating updrafts will lead to very real possibilities of large hail.  Also, the shear, divergence aloft and strong 250mb winds will lead to the chance for long-tracked supercells with a chance for a few tornadoes.

The plan right now is for me and my chase partner, Greg Zamarripa, to depart Atlanta at 11:30am and head for either Columbus, GA or Macon, GA as a base.  We will then head out in any direction from there to intercept storms.  We hope to be in our target by 2pm EST.  Storm chaser Mark Aubin will be targeting the Florida panhandle for any severe storm activity that erupts farther south.

I will be broadcasting my storm chase live on the internet on Ustream.tv and Severestudios.com.  Between 11:30am and 3pm I will be streaming live at http://www.ustream.tv/channel/mike-phelps-mobile-weather-stream.  Then, from roughly 3pm EST onward I will be streaming live at http://www.severestudios.com/livechase as Mike Phelps.  On the ustream.tv broadcast the viewer will have the ability to not only view the live video, but also hear audio from within the chase vehicle.  You’ll be able to listen in on critical nowcasting conversations and storm chase strategies, so you’ll actually feel like you are riding along with us on the chase.  There is also a chat feature where you can interact with me via instant message, and I can talk to you live.  The severestudios.com broadcast will not feature audio, but the video could be spectacular at times since we will be streaming at that location during the height of the storm chase.  I will be available to the media for live phone interviews any time at 404-202-6317.

Now onto the snow prospects for Sunday.

This looks to be a classic late winter/early spring upper level snow events for parts of the Southeast.  The upper low drops in from the northwest bringing with it a supply of moisture, cold air and strong dymamics.  These events are notoriously difficult to forecast and the area of heavy snow that falls will be dictated very much by the exact path the upper level low takes.  Right now, I’d say a general trace to 3 inch snowfall looks like a good bet across TN, northern and central AL and GA, much of SC and much of NC.  1 to 3 inches for Memphis, Birmingham, Huntsville and Chattanooga.  1-2 inches for the west Atlanta metro area, and 2 to 4 inches for the east and northeast ATL metro.  3 to 6 inches for Athens, GA.  4 to 7 inches for Greenville, SC.  I won’t venture to throw out a snowfall forecast for Columbia, Charlotte or Raleigh just yet, but they could also make out very well.  I also believe someone in the Southeast is going to see some “jackpot snow”of a foot or more, but it is impossible to pin down who that will be at this juncture.  I hope it is my backyard!  🙂  Now having said all that, I do need to caution that the bust potential with upper level snow systems in the Southeast is very high.  Honestly, we are not going to have a fully confident handle on this thing until it is happening.  The cities I listed above could just as easily end up seeing a lot less, or a lot more.  Definitely a system to monitor closely as there are sure to be several changes in the forecast over the next 24 to 36 hours.

I will also be streaming live video of the snow storm, and I will have more details on that in my blog entry Saturday evening or Sunday morning.

Still a Little Snow Possible in Dixie This Weekend, But Not Much

My thoughts and prayers are with all of those impacted by yesterday and last night’s severe weather.

The forecast models still indicate a chance for light rain changing to a period of light snow across TN, north MS, north AL and north GA this Saturday into Sunday morning, but the trend is for less moisture and less cold air.  So, that translates into some flakes, but nothing that is going to add up to a whole lot.

I think most areas north of I-20 could see a brief transition to some light snow through the day Saturday and Saturday night.  No accumulations except for a dusting to an inch across the higher elevations of northeast AL and north GA.  TN could make out a little better with 1-2 inches possible for the Plateau, and 1-3 inches for the mountains.

It’s too early to say if this is the last chance for significant wintry precipitation across the Southeast, but we are getting really close to officially pulling the plug on winter down here.  It really is starting to look and feel a lot more like spring.

Tornadoes Possible in Dixie Today. Snow Likely on Saturday. Get Ready for a Wild Few Days!

It is going to be a classic wild weather ride across the Southeast United States over the next several days.

A storm system today and tonight will bring the potential of severe thunderstorms across a good portion of LA, MS, AL, GA and north FL.  The threats with these storms will be large hail, damaging winds, and tornadoes.  In fact, the tornado threat is looking rather significant for the southern half of MS, and the southrn 2/3rds of AL.  Also, if mid 60 degree dewpoints make it into GA this afternoon, then a significant tornado threat would also exist for areas in GA along and south of interstate 20, and this would include the Atlanta metro area.

Overall, the potential violence of this event will very much be dictated by the degree and depth of moisture across the Southeast.  As of late morning, many dewpoints in the threatened areas of AL and GA are only in the low to mid 50s.  Dewpoints will need to rise into the 63 to 67 degree F. range to provide the sufficient low level moisture to fuel robust and deep convection necessary to produce tornadoes.  This will be a situation where the true potential of this event may not be fully realized until mid to late afternoon today.  There are still several factors that could significantly limit the overall threat and only time will tell whether those factors will go away or remain.  So, it will be very important for those across the Southeast to stay up to date on the latest weather information as the day progresses.

Now for the winter weather threat fro Saturday into Sunday morning…

This threat has been on the models for several days, and is trending stornger with each model run.  I am very hesitant to take the bait on any model threat beyond two or three days given the poor performance of the forecast models in this range this season.  I will say that I am cautiously opitimistic that a swath of light snow will progress from northwest to southeast across areas mainly along and north of I-20/I-85 Saturday into Sunday morning.  Accumulations could range from nothing to a dusting, to several inches.  It is just too early right now to say much more than state that this is a potential winter weather threat.