Severe Weather & Tornado Outbreak Likely Tomorrow

March 1, 2012

Good morning everyone! Enjoy the calm before the storm as we are expecting a major severe weather and tornado outbreak tomorrow from portions of the Ohio Valley all the way to the Gulf Coast. 

Let’s take a look at the set-up and why a widespread severe weather outbreak is likely:

A strong low pressure system will develop over the Southern Plains and move into portions of Northern Illinois by late Friday Evening. A strong southerly flow will help advect very warm and moist air into the Ohio and Tennesssee Valleys ahead of the low pressure system.

As the low pressure strengthens, a strong jet stream will interact with the system and create what we call directional wind shear. This wind shear is what helps storms form, sustain themselves and eventually begin rotating. Here’s a look at the wind shear tomorrow evening. The red and purple values are VERY high.

A strong southerly flow will usher in very warm and moist air into the Ohio Valley. Temperatures will climb into the 60’s as far North as North Central Indiana and Ohio. Here’s a look at what one of our forecast models is showing temperature wise tomorrow evening at 8:00 PM. 

Storms should begin to fire across portions of Illinois down into Eastern Missouri and Arkansas by the mid afternoon hours. These storms will quickly move into the Ohio and Tennessee Valleys and portions of Northern Mississippi and Northern Alabama. All of the ingredients are in place for a very violent day of severe weather with the potential for very strong and long lived tornadoes.

Here’s a look at what one of our forecast models is forecasting radar reflectivity for tomorrow afternoon:

The Storm Prediction Center has issued a rare Day 2 Moderate Risk from Indiana and Ohio down to portions of Northern Mississippi and Northern Alabama. Here is a look at the Storm Prediction Center’s Outlook for tomorrow:

The storm prediction center is forecasting a severe weather event in the moderate risk area with widespread damaging winds and potential for strong and violent tornadoes.

Here’s our outlook for tomorrow which is very similar. The areas we outline as numerous and outbreak likely should be prepared for a very rocky day of weather.

We encourage everyone to have their severe weather plans ready and to purchase a NOAA weather radio! Stay tuned to SWAT & IndianaWeatherOnline for the latest information.

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Powerful Storm Brewing

October 17, 2011

An extremely powerful early Fall weather system is brewing and will begin developing as early as tomorrow. A strong low pressure system induced by a strong polar vortex will merge and morph with a disturbance coming out of the Gulf of Mexico. This disturbance moving North out of the Gulf of Mexico will bring an abundant amount of moisture with it. As the warm and moist tropical air moves North, the warm and moist air (latent heat release) will help strengthen the morphed weather system as it travels North along the Spine of the Appalachian Mountains.

The water vapor imagery essentially tells the story this evening. You can see the large area of disturbed weather across portions of the Gulf of Mexico. The second system that will be a factor in this eventual large and phased weather system is a developing weather system across portions of Colorado. The extremely dry air across portions of Arizona and New Mexico is associated with our third player in this developing storm system and that is a very strong jet stream.

Nearly all of our forecast guidance has locked on to a solution of a strong weather system developing and moving into portions of the Midwest and Eastern Ohio Valley.

As the weather system begins to develop along the East Coast on Tuesday, strong and severe storms will be possible across the Southeastern United States. Increasing shear and an extremely tropical and buoyant atmosphere will lead to the threat of tornadoes from Florida into Georgia and eventually South Carolina.

This strengthening weather system will bomb out across portions of the Eastern Ohio Valley, strengthening possibly to as low or near 980 mb. This type of track is rare, as most storms that develop in this manner have a coastal low that transfers off the Mid Atlantic coast and tracks up the Northeast coast verses strengthening over land.

The track of his system means that a very large area will be impacted with heavy rain occurring from Florida all the way up the Appalachians, through the Ohio Valley and into portions of the Interior Northeast.

As the system reaches it’s peak intensity over the Eastern Ohio Valley and Eastern Great Lake states Wednesday and Thursday, extremely strong winds are also possible. You can see the tight wind field noted by the extremely close isobars around the low pressure.

With extremely impressive height falls as the low pressure deepens, it is not out of the question that some light snow could fall across portions of Northern Illinois, Southern and Eastern Wisconsin, Northern and Northwestern Indiana and Western Michigan. Obviously with extremely warm ground temperatures and fairly warm lower and mid level temperatures, no accumulation would occur, but the fact that some wet snowflakes are possible is definitely impressive.

Stay tuned to our facebook page for the latest on this developing storm system over the next 24-48 hours (www.Facebook.com/SWATChasers).


Weather Wise: What is a gustnado?

August 17, 2011

Since there has been some speculation that a gustnado may have developed along the gust front as it struck the Indiana State Fair causing the stage collapse and mass casualty incident, I figured I would take time to post a weather wise blog explaining what gustnadoes are!

While there are some theories that a gustnado may have struck the Sugarland stage at the Indiana State Fair causing the stage collapse, that is neither here nor there as far as this blog entry is concerned. I will tell you however that there were several documented gustnadoes across Central and Western Indiana on Saturday Evening, August 13th, 2011.

A gustnado is a specific type of a short-lived, low-level rotating cloud that can form in a severe thunderstorm. Gustnadoes form due to non-tornadic cyclonic features in the downdraft from the gust front of a strong thunderstorm, especially one which has become outflow dominated. While they often look similar, gustnadoes have very little in common to their big brother, the tornado. Gustnadoes are outflow dominated and often form along gust fronts, while tornadoes form from a rotating supercell and mesocyclone.

One of the key differences and easiest ways to determine a gustnado verses a tornado is that gustnadoes are often not attached to any cloud structure. Tornadoes on the other hand extend down from a rotating wall cloud, a cloud feature that often develops in a supercell thunderstorm. Gustnadoes, while not true tornadoes, can become quite wide and can even be long lived. Gustnadoes should be considered dangerous as they often produce winds in excess of 60 to 70 mph. Gustnadoes have and can do damage.

The picture above is a rotating supercell and associated wall cloud. Wall clouds often have that circular and lowered look and typically rotate, some times quite violently. Most tornadoes develop from wall clouds and supercell type thunderstorms.

The picture above was taken by SWAT Chasers outside of O’Neill, Nebraska on May 30th. The storms that day quickly became outflow dominant and the storms produced numerous gustnadoes all across Central Nebraska. Some of the gustnadoes became quite wide including one we chased which was over 1/2 mile wide. The picture above shows that the rotating column of air, dirt and debris was clearly a gustnado as it was not attached to any wall cloud or lowered cloud base. This particular gustnado occurred on a gust front that surged out ahead of a supercell. What was rare about this particular incident was that to the East of our location, a large gustnado was swirling on the ground. To our West under the actual mesocylone, a tornado briefly touched down under the wall cloud in an open field.

Gustnadoes are often confused and interpreted to be tornadoes by the public and even law enforcement and public safety officials. As stated above, the simplest way to tell a gustnado from a tornado is to check and see if there is a connection to a rotating cloud base. If there is, it is a tornado. If there is not, it is likely a gustnado. If you see a gustnado approaching, you should seek shelter as they can produce strong winds and cause damage.

I hope this blog gave you a little bit of a better understanding of gustnadoes so that when us weather people use the term in the future, you will have a better idea what we are talking about!

Thanks for reading!

Brandon Redmond
SWATChasers.com

P.S. Don’t forget that you can book your storm chase tour with SWATChasers for the 2012 storm chase season! We are offering week long tours that will offer guests a chance to see the incredible Great Plains, Severe Thunderstorms and hopefully tornadoes! You can check out our tour schedule and find more information at SWATTours.com