Well, here it goes. There is a wave of showers and thunderstorms moving east-northeast across middle Tennessee right now, slowly but surely making its was across the state. This is only the very edge of the system, the outskirts, as it were. Through the night more of the system will push through, a more severe part of the system. Parts of EXTREME middle Tennessee are already under a tornado watch until 3 A.M. tonight, with potential for tornadoes, large hail, and damaging winds. The stats on the watch page says the following:
Tornadoes: High
EF-2+ Tornadoes: Moderate
Severe wind: High
65 kt+ Wind: Moderate
Severe Hail: Moderate
2″+ Hail: Low
The watch spans an area from Arkansas to Kentucky, and all in between. The image of the watch is above. Also, here is the text from the tornado watch, giving a bit more info on the situation.
DISCUSSION…STRENGTHENING/MOISTENING WAA/SSWLY LLJ EXPECTED TO SUPPORT CONTINUED DEVELOPMENT OF SUSTAINED STORMS/COMPLEX SUPERCELL STRUCTURES AND MESOSYSTEMS WITH AN ATTENDANT THREAT FOR TORNADOES ACROSS A SIZABLE PART OF THE LWR MS AND LWR TN VLY THROUGH EARLY SAT.
However, the worst is yet to come. As the warm front pushes in tonight, the cold front will do so tomorrow which will bring out greatest chance for severe weather. These are the only counties in risk for severe weather TONIGHT ONLY, but tomorrow everyone is under equal risk.
The hourly weather graph doesn’t give any hope in figuring out when the next (and worse) round will come, but our local National Weather Service has updated their Hazardous Weather Outlook, which gives out a lot more information on timing. From the NWS’s HWO:
1000 PM CDT FRI APR 23 2010
THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE. .DAY ONE…TONIGHT
WITH A DEVELOPING COLD FRONT APPROACHING FROM THE WEST…THUNDERSTORMS MAY DEVELOP LATE TONIGHT. A FEW OF THESE STORMS MAY EVEN BECOME SEVERE IN AREAS WEST OF NASHVILLE BEFORE DAYBREAK.
.DAYS TWO THROUGH SEVEN…SATURDAY THROUGH THURSDAY
LOOK FOR WIDESPREAD STORMS TO DEVELOP SATURDAY AND SATURDAY EVENING AS A STRONG COLD FRONT PASSES THROUGH MIDDLE TENNESSEE. THE ENTIRE MID STATE IS UNDER A MODERATE RISK OF SEVERE WEATHER. SEVERE STORMS MAY OCCUR AT ANY TIME DURING THIS PERIOD…BUT WILL BE MOST LIKELY DURING THE AFTERNOON THROUGH EARLY EVENING. DAMAGING STRAIGHT-LINE WINDS…LARGE HAIL…AND ISOLATED TORNADOES ARE ALL POSSIBLE WITH THIS SYSTEM.
.SPOTTER INFORMATION STATEMENT…
A SIGNIFICANT SEVERE WEATHER EVENT IS EXPECTED. SPOTTER REPORTS WILL BE NEEDED.
But wait, there’s more!
A MODERATE RISK MEANS THAT THERE IS A 45 PERCENT CHANCE OF A SEVERE WEATHER EVENT (DAMAGING WINDS…LARGE HAIL OR TORNADOES) OCCURRING WITHIN 25 MILES OF ANY GIVEN LOCATION IN MIDDLE TENNESSEE.
THIS EVENING…A WARM FRONT HAS MOVED NORTH INTO CENTRAL KENTUCKY WITH OF A LARGE AREA OF SHOWERS MOVING INTO SOUTHERN PORTIONS OF THE MID STATE. SCATTERED SHOWERS HAVE ALSO DEVELOPED AND ARE MOVING ACROSS AREAS ALONG AND NORTH OF INTERSTATE 40 AND GENERALLY ALONG AND WEST OF INTERSTATE 24. THIS WARM FRONT WILL CONTINUE TO LIFT NORTH OVERNIGHT…PROVIDING FOR INCREASING MOISTURE AND INSTABILITY ACROSS THE ENTIRE MID STATE. THIS..ALONG WITH STRENGTHENING LOWER LEVEL AND UPPER LEVEL WINDS…COULD BRING A ROUND OF SEVERE THUNDERSTORMS INTO WESTERN PORTIONS OF MIDDLE TENNESSEE OVERNIGHT… ESPECIALLY JUST ALONG AND EAST OF THE TENNESSEE RIVER VALLEY. A TORNADO WATCH IS IN EFFECT UNTIL 3 AM CDT FOR BENTON…HOUSTON… HUMPREYS…MONTGOMERY…PERRY…AND STEWART COUNTIES. THUNDERSTORMS THAT DEVELOP IN THESE COUNTIES COULD PRODUCE LARGE HAIL…THUNDERSTORM WIND GUSTS TO 70 MPH OR GREATER…NUMEROUS CLOUD TO GROUND LIGHTNING STRIKES…AND ISOLATED TORNADOES.
ANOTHER ROUND OF STORMS…THAT WILL LIKELY CONTAIN DAMAGING WINDS… LARGE HAIL AND ISOLATED TORNADOES WILL MOVE INTO SOUTHWEST MIDDLE TENNESSEE AROUND 8 AM AND MOVE NORTHEAST INTO THE NASHVILLE AREA BY 10 AM. FROM 10 AM ON THROUGH THE AFTERNOON HOURS…SUPERCELL THUNDERSTORMS ARE LIKELY THROUGHOUT MIDDLE TENNESSEE…WITH TORNADOES POSSIBLE.
THIS IS THE STRONGEST STORM SYSTEM TO AFFECT MIDDLE TENNESSEE SO FAR THIS SPRING…AND THE POTENTIAL FOR SEVERE WEATHER LOOKS TO BE INCREASINGLY LIKELY…INCLUDING TORNADIC SUPERCELLS.
So, as stated above, severe weather will be possible ANY TIME during the day, but more likely in the afternoon/early evening. The Storm Prediction Center has not updated their discussion on the event, but I will certainly be checking it in the morning. However, I do not know if I will have the time to make another post. It all depends on the weather, and how soon I leave to go spot this for the NWS.
So all we can do now is wait. Thankfully we shouldn’t be caught by surprise by anything severe tonight while we sleep, but keep your weather radios handy just in case. I honestly have no idea how this is going to pan out, which is why I have tried my best not to hype this post up as much as the others! 
And so it begins… what the National Weather Service calls, “the strongest storm system to affect Middle Tennessee so far this spring”. Be safe.
