A few widely scattered showers will develop out ahead of the main precipitation shield; however, the heaviest weather is not due in until around 6am or perhaps slightly later. The low level winds are fairly ROBUST with H85 winds of 60-70kts forecast. Since the strong winds will not have far to go to reach the surface, it will not take much convection for them to reach the surface and possibly cause issues.

The 0-1km helicity forecasts are a bit worrisome with 350-400m2/s2 right over us as the line of storms move closer toward the area. One limiting factor is the time of day and lack of instability. SBCAPE values of 250j/kg are not out of the question; however, with such a volatile wind profile I would tend to think weaker updrafts (updrafts that will be fed on upper level ascent) would easily get rolled and eventually destroyed.

This event is very classic in terms of cool season severe with low instability and high shear. The best chance for tornadoes in general appears to be west of here where instability values are higher; however, given strong shear and strong forcing I can’t rule out a spin up here or there. EHI (0-1km) values of around 1 or slightly higher are forecast for this time period. This value is relatively low considering higher end events; however, given the time of year it is still rather impressive. Again, for that reason I simply can’t rule out a possible spin up.

With that said, I do not expect a widespread tornado outbreak by any means. I am very concerned about the possibility of strong damaging winds that will accompany the line of storms as it moves eastward. Even heavier shower activity may be enough to pull some of the wind energy down to the surface. Due to the lack of instability and fairly low topped convection, lightning may be limited with these cells as well.

Again, timing looks to be between 6am and 10am given model disagreement. Often times squall lines tend to surge forward a bit faster than forecast so that is why I’m thinking 6am at the earliest and 10am given the slower guidance. The morning rush looks very wet and windy. Be sure to keep both hands on the wheel as you drive and use extra caution if you drive a high profile vehicle.

Summary:

-Severe storms are possible
-Strong possibly damaging winds are the primary threat
-Can’t rule out an isolated tornado; however, no widespread tornado outbreak is expected
-Limited lightning
-Brief heavy rainfall

Residents are urged to be ready to act and know what to do if a watch or warning is issued for the area. Stay safe and stay informed.

Meteorologist: Robert Frye
Updated: 7:00pm CST 1/29/13

The reason we’re not as immune as many think is due to the Gulf of Mexico being our primary source for warm air and moisture. In the cooler season, a southerly wind from that direction usually brings us warmer and more humid conditions. The same can be said for the summer. Ever wonder why the Sequatchie Valley is so humid during the summer? Well, if the Gulf of Mexico wasn’t there it would be significantly drier and not nearly as rainy. This warm rich air that moves into the region from the gulf is one ingredient that can bring us severe weather.

In all seasons except summer and early autumn, we usually get frontal boundaries from the northwest that cool us down and dry our air. Out ahead of the cold front, winds turn out of the south and spread the warmer more humid air from the gulf northward. The interaction between the warm moist air and cooler dry air causes widespread showers and storms, especially along or slightly ahead of the cold frontal boundary.

With that said, we are NOT immune to tornadoes during the late summer months and early autumn months. Land-falling tropical storms and hurricanes can move into the region and bring flooding rains, gusty winds, and even isolated weak tornadoes. For this reason, it is important to be aware of the weather and be ready to act when watches and warnings are issued for your area.

There are many ways to keep updated on current watches and warnings. You may purchase a weather radio with S.A.M.E. technology at many retail outlets that sell electronics. These radios can be found at the RadioShack in Kimball Crossing as well as Walmart, and were also available at CVS in Jasper in the past.

For those that use smartphones, there are several cheap and even free apps that can be bought to alert you to any threats. One app, offered for FREE is the ReadyTN Mobile Preparedness App from the Tennessee Emergency Management Agency. You can learn more about the ReadyTN app here.  Also, many cell phone service providers offer free text messages of alerts using the phone GPS. Check with your cell phone service provider to determine whether or not your device is capable, and whether or not they offer these messages.

For those still “wired” with a landline phone, the county’s Reverse 911 system can also be activated to alert residents. This system is already setup for area land line phones, however citizens can add cell phone numbers and their email, if they wish, by visiting www.marioncosheriff.com and click the “Sign Up for FREE Emergency Alerts”  button on the right side of the page and following the prompts to register a new user. The user will receive an email notifying them that their information has been received and they are active on the system. Local emergency management officials urge those with elderly family members in the area with cell phones to help register those family members.

Marion County Sheriff Ronnie “Bo” Burnett advises residents,  ”If there are elderly residents that need help registering their cell phone, they can call the sheriff’s office (423-942-2525) and we’ll make sure we get them into the system.”

Stay with MarionCountyMessenger.com online, on Facebook, and follow us on Twitter for the very latest weather information.

Timing of the precipitation varies a bit from forecast model to forecast model. I have decided to blend all available guidance and place a range of times that impacts will be felt across the valley. It looks like light freezing drizzle will start between 5am and 7am CST. Travel problems will likely initiate shortly after precipitation initializes in the higher elevations. The greatest threat for icing in the Sequatchie Valley will be as relatively heavier precipitation moves in around mid to late morning or so just before temperatures warm above freezing.

Expect bridges and overpasses to become icy for your morning commute. I am VERY confident that no one will see a single flake of snow from this system. Max surface to H500 temperatures will be just shy of 10C allowing for complete melting of ice nuclei. Given this, sleet is even doubtful, especially as time progresses.

It looks as if temperatures in the valley will warm above that critical 32F mark around noon. Being consistent with ranges, I’d say the transition will occur between 11am and 1pm. Chattanooga and points east will change over a bit later than Marion Co as the wedge of high pressure (responsible for the shallow pool of cold air leading to freezing rain) breaks down. As expected, higher elevations will take a bit longer to change over as a sharp temperature contrasts will be recognized between the surface and 3Kft. I expect a change over in these locations between 1pm and 3pm.

Ice accumulations look light for the most part. QPF (precipitation amount forecast) only indicate .05”-.15″ during the duration of the freezing temperatures for valley locations. Heavy amounts will be located north and west of the area and will not arrive until after the temperatures increase. For this reason, the National Weather Service decided to go with a lower category headline (Freezing Rain Advisory) rather than the more significant Winter Storm or Ice Storm alerts. Rain will end rather quickly at sunset or a little before.

Friday’s Forecast:

*Freezing Rain Advisory in effect through Friday Evening*

Friday- Freezing drizzle early then light freezing rain before 1pm with rain likely after 1pm. High Temperatures will be around 38F in the valleys. Higher elevations will reach around 34F degrees. Valley ice accumulations look to be between 0.05” and 0.15”. Higher elevations will receive between .1” and .2”. The highest elevations may experience “some” power issues; however, those should remain only isolated at best in those location.

Meteorologist: Robert Frye
Issued: 7:00pm CST 1/24/13

Marion County Schools - 1 1/2 hour delay

Richard Hardy Memorial School- Students will report to class at 9:30 a.m.

Hamilton County Schools- 2 hour delay

Orange Grove Center- Buses ONLY will operate on a 2-hour delay Tuesday.

Scenic Land School – 2 hour delay

Hickory Valley Christian School – 2 hour delay

Polk County Schools - 2 hour delay

Chattooga County Schools – 2 hour delay

Catoosa County Schools – 2 hour delay

Notre Dame High School – 2 hour delay

OLPH – 2 hour delay

St. Jude School – 2 hour delay

Walker County Schools – 2 hour delay

Chattanooga Christian- 2 hour delay

Rhea County Schools – 2 hour delay

Sequatchie County Schools – 2 hour delay

Bledsoe County Schools – 2 hour delay

Chickamauga City Schools – Opening at 9:30

Dayton City Schools - 2 hour delay

Ooltewah 7th Day Adventist School - 2 hour delay

St. Nicholas School - 2 hour delay

21^ST Century Child Development Center – 2 hour delay

Boyd Buchanan - 1 hour delay

Brainerd Baptist School — Classes begin at 10am

The warning states that dangerously hot and humid weather is expected to continue through Wednesday across much of those areas.  The warning also states that very high low-level tropical moisture from the Gulf of Mexico combined with a ridge of high pressure is causing the very hot and humid weather across these areas.

The agency further says that a combination of the very hot temperatures and high humidity will cause dangerous heat reading above 110 degrees today and between 105 and 115 degrees on Wednesday, when scattered showers and thunderstorms may bring some relief. 

Tennessee, Alabama, and Georgia are included in the heat warning.

CNN is reporting that the National Weather Service had 23 states under heat advisories on Monday, including the states mentioned as well as Oklahoma and Kansas.

The Kansas City Star published an Associated Press report stating that the heat wave is smothering residents, crops and animals alike.

Hutchinson, Kansas was listed as one of the hottest spots in the nation Sunday after temperatures hit 112 degrees and Wichita hit 111 degrees, National Weather Service meteorologist Chance Hayes told the Associated Press on Monday.

Records show temperatures of 111 have been reached only ten times in Wichita since 1888, according to The Associated Press article.

June also brought extreme temperatures and precipitation across the U.S., according to a National Weather Service press release, as an oppressive heat wave, accompanied by intensifying drought conditions, shattered temperature records in the South and Southwest.

The nation had its 19th driest and 26th warmest June on record, according to scientists at the National Oceanic Atmospheric Administration’s (NOAA) National Climatic Data Center in Asheville, N.C.

The average U.S. temperature in June was 70.7 degrees (F), which is 1.4 degrees above the long-term 1901 to 2000 average, according to the  Weather Service. Meanwhile, precipitation across the nation averaged 2.48 inches. That figure is 0.41 inch below the long-term average, with large variability in different locations, the National Weather Service states.

Radar Image from WeatherTap.com

Severe Weather Outbreak Expected across the Sequatchie Valley with Strong Damaging Winds, Large Hail and even the possibility of violent long-tracked tornadoes.

The Storm Prediction Center in Norman, Okla has placed the Sequatchie Valley in a “HIGH RISK” for severe weather. SPC usually issues a High Risk during the most dangerous severe weather outbreaks. Typically, High Risks are issued for areas of the Great Plains in response to potentially deadly severe weather outbreaks. Here in the Sequatchie Valley… High Risks are rare. The last High Risk in the Sequatchie Valley was in 2009. There have been only four high risks ever for the Sequatchie Valley.

What does this mean? ALL residents should be on heightened alert for severe weather on Wednesday. Timing looks to be midday and thereafter; however, Severe Storms will be possible throughout the day. Please heed all warnings and be ready to act quickly if severe weather threatens. This is being called a “Particularly Dangerous Situation” by the Storm Prediction Center!!!

Meteorologist: Robert Frye
Updated: 4/27/2011

MarionCountyMessenger.com Staff Meteorologist Robert Frye explains…

Technical Discussion:

Forecast guidance indicates cyclogenesis will occur over the southern plain states on Monday along a quasi stationary frontal boundary draped across the southern plains into the Mid-Miss River Valley. Aloft, strong 300mb jet axis is also projected to set up across Oklahoma, Texas, and Arkansas. At the same time a shortwave will progress eastward and take on a more negative tilt. The stationary front south of the low is expect to SLOWLY move eastward as a cold front and a warm front will push northward through the Midwestern states in response to a (very slightly) more progressive mid-level flow. The initial low is projected to eject northeastward along the slow moving frontal boundary through late Monday and Tuesday. Secondary cyclogenesis is currently being advertised by both global and mesoscale models just east of the Ozarks (again) along the boundary. This secondary low is expected to move northeastward through Tuesday Night and Wednesday.

Severe Storms are expected to develop Tuesday Afternoon over the Mid-Miss River Valley. Storms are expected to move SW to NE along the slow moving cold front upstream. However, due to strong WAA associated with a 40-50kt LLJ, isolated convection is possible. Isolated severe storms are possible Tuesday Evening; however, instability and any severe threat will decrease during the overnight hours.

As the front finally approaches the region, numerous showers and tstorms will be possible Wednesday Afternoon and Evening. Given cape of 1500-2000 j/kg and 0-1km SRH of 200-250 m2s2, severe thunderstorms will be possible as the front nears. Currently, a squall with damaging straight-line winds (especially in bowing segments) looks to be the main severe weather threat at this time. However, due to moderate wind shear (0-3km SRH of 300-350 m2s2), we certainly can’t rule out a tornado threat. There remains a good bit of uncertainty as models differ on timing and strength of the secondary low that is expected to form Tuesday Afternoon.

Forecast:

Tuesday Evening/Overnight- Isolated showers and thunderstorms are possible. An isolated severe storm or two will be possible early.

Wednesday- Numerous showers and thunderstorms expected (especially in the afternoon and evening hours). Some storms may be severe.

Meteorologist: Robert Frye
Updated: 4/24/2011 at 11:08 PM

The National Weather Service office in Morristown, TN issued a tornado watch for a broad area of southeast Tennessee a short time later as the storms pushed eastward across the state.

All of East Tennessee, the Cumberland Plateau and southeastern counties of Middle Tennessee were under tornado watches Wednesday morning until 10am ET.

These same thunderstorms we saw were the same storms that caused wind damage and lightning strike damage earlier in the morning hours in Western and Middle Tennessee.

AP reports state that trees were blown down in Middle Tennessee, damaging some houses, blocking roads and causing at least one school system to cancel classes. The Stewart County Schools in the northwest corner of Middle Tennessee closed for Wednesday.

Officials with the Tennessee Emergency Management Agency (TEMA) says there have been no reports of deaths or injuries from the storms.

In Nashville, fire officials say a home under construction burned to the ground after it was hit by lightning.

No reports of serious damage have been made in Marion County or neighboring counties at this time.

The storms and the downpour of rain with them were however likely the cause of one interstate snarl Wednesday morning.

Commuters traveling along I-24 Eastbound towards Chattanooga were stalled around 8am CT when a car flipped over around mile marker 173 (between the Georgia state line and Lookout Valley) and blocked a lane of traffic.

Other Interstates in Chattanooga also saw similar slow-downs as the rain wreaked havoc on the Wednesday morning commute.

MarionCountyMessenger.com Staff Meteorologist Robert Frye says the possibility of showers and thunderstorms will continue through the day today and through week’s end.  Gradual clearing is expected Friday afternoon and evening, with partly cloudy and warm conditions for Easter weekend.

Right now, all SVR threats are possible given current parameters. Surface based CAPE will be roughly around 1000 to 1100 J/kg as mid level lapse rates steepen in response to a (modest) EML. This differential advection inversion will help cap us off early; however, storms should initiate near the Mississippi River around midday (due to surface heating and front frontal lifting) and progress steadily eastward through the afternoon hours. SRH is expected to be modest early on; however, as the frontal boundary nears, SRH will increase to 250-300 m2s2. Large hail and damaging winds will likely be the main threat with this squall line; however, given vertical shear profiles, isolated tornadoes will also be possible across the entire region. If surface winds back a bit more, the risk for tornadoes will increase dramatically. If discrete storms form ahead of the squall line, storms will have the potential for large hail, damaging winds, and tornadoes. With sharply curved hodographs out ahead of the cold front, some tornadoes may be strong and long tracked. However, at this time that potential is low and only exists well north of the Sequatchie Valley. There is a bit of uncertainty in the timing of the event and some SVR parameters will still need to be evaluated as the event nears.

General Forecast:

Monday:
Increasing Clouds and windy. Widespread showers and Thunderstorms (some will be severe) will move into the region by early evening. High temperatures will top out in the mid to upper 70’s. Southerly winds of 10-20 mph are expected with higher gusts. (Much higher gusts expected in thunderstorms)

Monday Night: Showers and thunderstorms early. Wind shifting from southerly to northwesterly with the passage of the cold front. Lows will bottom out in the lower to mid 40’s.

It is advised that all residents in the Sequatchie Valley stay aware of the weather situation Monday Afternoon. Be ready to act if severe weather watches/warnings are issued by the National Weather Service. Also, make sure your weather radio is in working order and in alert mode.

Meteorologist: Robert Frye
Updated: 4/3/11 at 12:45 AM

Given the saturated soils from previous heavy rains… flooding and flash flooding will be possible. Be advised that flooding conditions will likely occur on the Sequatchie River and its tributaries. With low flash flood guidance, the Little Sequatchie River may also flood due to already high river levels. Please do NOT drive into flooded roadways. Do NOT allow your children to play in and around standing flood water.

The National Weather Service has issued a Flood Watch through Wednesday evening. Remember the National Weather Service’s slogan… Turn around… Don’t drown.

Meteorologist: Robert Frye
Issued: 3/09/2011