Saturday, January 28, 2012

1/28 - 3:30pm - A Tranquil Forecast, Thundershower Photos

It doesn't get much better than this. After a bit of chilly weather today with highs in the 40's we'll be seeing the triumphant return of 50's and 60's next week across West Tennessee. This rather warm stretch of weather with sunny skies will extend all the way through to Tuesday. A few showers and storms could make their way into the region by Wednesday and Thursday, but other than that the rest of the week should remain rain-free for the most part. There are indications that some colder, more winter-like weather could arrive after next weekend, but we'll cross that bridge when we get closer to time. Check out your full forecast from this morning's edition of Good Morning West Tennessee on WBBJ below:

On Thursday a few thundershowers rolled through Mississippi State University as a cold front made its way across the region. Since skies had cleared out from the day's previous storms, the coupling of the sunset and the thundershowers with clear air around them made for some nice photos. A "silver lining" of one of these thundershowers is posted on the right and a panoramic view of the MSU campus from the 4th floor of my building as the showers rolled through is below:

Click photo for a larger view.

Wednesday, January 25, 2012

1/25 - 6pm - MSU Forecast and a Look Back at Monday Morning's Storms

Another bout of severe weather is affecting the South as a powerful line of storms continues to push through Louisiana. These storms have spawned some tornadoes today across Louisiana and Texas while a Tornado Watch remains in effect for areas from Lake Charles, Louisiana to just south of Greenville, Mississippi. We'll be watching these storms as they track into eastern portions of Mississippi tomorrow morning. There's a chance they could be severe here in Starkville and the Golden Triangle, but the main threat should remain south of the area. Once these storms clear out we'll be left with a fantastic few days heading into the weekend. Find out more in your full forecast below:

from ABC 33/40 on Flickr
A place that's no stranger to tornadoes was hit again early Monday morning as storms dropped ten tornadoes in Alabama. The house on your left was hit by a tornado in Trussville, which is just northeast of Birmingham. These tornadoes caused over 100 injuries and at least two deaths as they moved through the darkness. Be sure to check out NWS Birmingham's updated public information page regarding this event to see the strengths and tracks that these tornadoes took. Arkansas was also hit badly by tornadoes (at least four as damage assessments continue) and you can read a synopsis of the severe weather event in that neck of the woods from this page posted by NWS Little Rock.

West Tennessee managed to escape the brunt of this system, but the National Weather Service in Memphis is investigating an area of damage near Lexington, TN (Henderson County) for a possible tornado. They've already confirmed straight-line wind damage in both Memphis and Middleburg, TN so far. NWS Memphis also has a page where you can see their ongoing assessment of damage in the area. UPDATE 12:10am: NWS Memphis has now confirmed an EF-1 tornado in Henderson County near Lexington, TN:
5 S Lexington [Henderson Co, TN] nws storm survey reports TORNADO of F1 at 22 Jan, 11:58 PM CST -- ef1 tornado with estimated winds of 105 mph touched down 5 miles south of lexington and continued east 8 miles. numerous trees were uprooted or snapped along the path. a roof was blown off a house. a shed in the backyard was also destroyed. the tornado touched down on primarily ridge tops before eventually lifting just northeast of butterscotch road. maximum width 150 yards.
This event again underscores the need for more ways to get the warning out to folks, especially during an overnight event when people are asleep. The best way to do this is have a NOAA Weather Radio in alert mode by your bedside or to have an app on your iPhone like iMapWeather Radio. There are text-based alerting solutions offered by individual TV stations and networks too.

Saturday, January 21, 2012

1/21 - 11pm - Severe Weather Outbreak Possible Tomorrow

A line of strong storms moved through West Tennessee this morning, but what's on the way for tomorrow evening could be even more potent with the potential for damaging winds and tornadoes. Check out my broadcast from this morning below to see what all this means and then continue on below the video for a detailed severe weather breakdown:

Timing and Threats

The Storm Prediction Center has issued a Slight Risk with a 30% hatched area for tomorrow's severe weather event from Mississippi to Indiana. The main time frame for these storms to roll through West Tennessee and Mississippi will be from 5pm tomorrow to 3am Monday. This does not mean ten straight hours of storms in any one location, but rather a ten hour window where storms will be affecting the region. Wind damage and hail will be the most common threats, but this could also be a significant tornado event. Some individual supercells or cell clusters may form ahead of a main QLCS (squall line) of storms late tomorrow afternoon and evening. These front-running storms, should they form, would be the ones with the highest tornado risk, but both the line of storms and the individual cells could produce a significant tornado or two. The SPC's wording on their Slight Risk outlook is fairly strong:



The setup for tomorrow's severe weather event is fairly classic. A large trough will be moving through the region providing increased wind speed aloft, which increases instability and provides wind shear. This trough will also be negatively tilted, meaning the axis or tightest gradient of the trough will be leaning from southeast to northwest as you see in the graphic to the right from the 0z NAM model. This negative tilting further increases wind shear because the upper level winds take on a more southerly component rather than a southwesterly one.

Not only will we have wind shear between the surface and aloft, but also the surface and the low levels of the atmosphere too. This low-level shear is essential for tornadoes to form and for storms to overcome low levels of instability. The NAM output has quite a bit of low-level shear from Mississippi all the way to Kentucky, so that's a pretty good indication that rotating storms and tornadoes will be possible during the duration of this event tomorrow.

The amount of moisture that will be surging up from the Gulf of Mexico while the region is in the warm sector of this system is going to be tremendous. The current dewpoint in Starkville, Mississippi is 41 degrees, but by tomorrow evening we'll be in the 60's. That is certainly enough moisture to supply the atmosphere with the needed instability for severe weather.

When you put together these factors plus the idea that we may have CAPE (instability) values over 1000 J/kg, you get a fairly decent tornado risk. The Significant Tornado Parameter exceeds 2 on the 21z SREF model at 9pm and midnight (1/23) tomorrow and has been fairly consistent on the last few runs of the SREF. This is not "off the charts" or anything like that, but it's enough to raise eyebrows. As stated above, both individual cells and the main QLCS line of storms could produce strong tornadoes. The QLCS will be especially difficult because there could be embedded supercell structures within it that produce tornadoes like an individual supercell would. I still think the highest tornado risk will be in Northeast Mississippi (Starkville, West Point, Columbus, Tupelo, Corinth, etc.), but the latest indications like the STP above are pointing toward that threat leaking over into southern portions West Tennessee as well.

I'll be updating my Twitter, Facebook, and Google+ accounts all day tomorrow as these storms roll through, so be sure to follow or friend me for the latest information.

Wednesday, January 18, 2012

1/18 - 3pm - Mississippi State Forecast, KY/IN Tornado Update

It's still cold out there in Mississippi after a frigid morning with temperatures in the 30's.  A cold front that passed through yesterday is to blame for the chill, but fear not, temperatures will be back to around 60 for highs by tomorrow afternoon. Quick turnaround, huh? Some rain and a few storms will be possible Friday night into Saturday with temperatures still increasing. A shot of severe weather may be possible sometime around the middle of next week, so keep watch for more updates on that forecast as it becomes clearer. Today's Mississippi State University forecast video is below:

Brownsboro Rd in Louisville
The count of yesterday's confirmed tornadoes in Kentucky and Indiana has now reached seven according to the National Weather Service in Louisville. The strongest of these was an EF-2 in Simpson and Allen Counties in Kentucky. Two of these tornadoes with winds of up to 100 mph occurred in highly-populated portions of the city of Louisville in Jefferson County. NWS Louisville is updating a webpage continuously with information about these tornadoes as it becomes available from their damage surveys.

Tuesday, January 17, 2012

1/17 - 5:15pm CST - A Day of Tornadoes in Kentuckiana and Mississippi

Two tornadoes have now been confirmed by NWS Louisville in Kentucky and Indiana. The first of these is an EF-1 that caused damage in the Springhurst area of Northeast Louisville (photos from John Belski's Weather Blog):

...EF-1 Tornado Confirmed in Jefferson County Kentucky...

Brownsboro Rd, Louisville
Damage Type: Tornado
Date: Jan 17 2012
EF Scale: 1
Wind Speed: 95 MPH
Path Length: 4.2 MILES
Path Width: 250 YARDS

Narrative: An NWS storm survey has confirmed an EF-1 tornado in Jefferson County, Kentucky.  The tornado touched down near the intersection of I-264 and Brownsboro Road.  The tornado tracked northeast to near the intersection of Hurstbourne and Brownsboro Road where it briefly lifted.  The tornado then reformed and crossed I-265.  The preliminary path length is 4.2 miles with a path width of 250 yards. This storm survey is ongoing and information in this statement will be updated as it becomes available.

The second tornado hit the airport in Madison, Indiana and carries an EF-0 rating with 85 mph winds:
...EF-0 Tornado Confirmed in Jefferson County Indiana...

Madison, IN Airport
Damage Type: Tornado
Date: Jan 17 2012
Start Time: 10:40 AM EST
End Time: 10:40 AM EST
EF Scale: 0
Wind Speed: 85 MPH
Path Length: 0.3 Miles
Path Width: 60 Yards

Narrative: An EF-0 tornado touched down at the Madison Municipal County Airport. Damage was confined to IMS Lane. The tornado touched down briefly along this path and moved an at least 500 pound dumpster 35 feet southeast. It also moved a Beechcraft/King Air plane 10 degrees and the nose gear was broken. The airport operations building had a disabled awning and post. Part of a hangar`s siding came off with siding and insulation up in trees. Several trees were snapped along the narrow path. A witness saw the swirl as the tornado touched down.
It's worth noting that the Storm Prediction Center did not issue a Tornado Watch today during this severe weather event. There may be more tornadoes confirmed in the Louisville area tomorrow as more surveys are conducted, especially in Clarksville, IN where damage has been well publicized. Two tornadoes were also reported in Mississippi this afternoon in Tippah and Marion Counties:


Ratings on these possible tornadoes will likely come tomorrow when NWS crews are able to get out and survey the damage.

Unfortunately severe weather could become an issue again this time next week as a potent trough moves through the Southeastern portion of the nation. The GFS and Euro computer models indicate ample upper-level support and moisture return for a severe weather setup, but this is not set in stone yet as things can change in a week's time. Stay tuned!

Saturday, January 14, 2012

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:

Thursday, January 12, 2012

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!

Thursday, January 5, 2012

1/5 - 12:30pm - The Real Cold is Coming!

After a brief period of bitterly cold temperatures earlier this week, most of the eastern half of the nation is beginning to recover. Highs in Louisville today will get into the 50's and West Tennessee could reach 60 in places. This is all thanks to southerly airflow under a ridge that's developing to the west. Temperatures will remain reasonably warm with a few small dips this weekend.The big story is what will happen during the middle of next week. The NAO (North Atlantic Oscillation) and AO (Arctic Oscillation) are forecast to go at least neutral or negative during this time, which means that the pattern will be ready to support an outbreak of cold air in the East. The computer models have had a very difficult time lately resolving when exactly these oscillations will go negative, but it seems like there's enough of a consensus now to say that this will probably happen. How long they will stay negative remains to be seen, but given the time of year we're in now I would expect the cold air to stick around for a while.

The next issue with this cold air is the possibility of snow. A storm moving through on Wednesday could produce a rain to snow situation for Kentucky and Tennessee on Wednesday night if the cold air moves in quick enough. This is certainly something to watch since the models are not picking up on this well at this time. What they are picking up on is the bitter cold in the wake of this system as a trough sits on top of the East US. If you didn't get the super-heavy jackets out this week, you'll definitely need them by the end of next week!

I'm heading back to Mississippi State for the spring semester, so my broadcasts at WBBJ will resume next weekend. See you then!