4 W State Line [Greene Co, MS] NWS STORM SURVEY reports TORNADO at 23 Feb, 5:45 PM CST -- A TORNADO TOUCHDOWN OCCURRED IN A HEAVILY WOODED AREA NEAR THE GREEN/WAYNE COUNTY LINE. EF-1 DAMAGE WAS OBSERVED AS NUMEROUS LARGE DIAMETER...GREATER THAN 2 FEET...HARDWOOD AND PINE TREES WERE EITHER SNAPPED OR UPROOTED. SIGNIFICANT DAMAGE OCCURRED TO A LOG CABIN BUILT IN 1909 JUST INSIDE THE WAYNE COUNTY LINE...WITH WINDOW PANES BLOWN OUT AND LARGE PORTIONS OF THE ROOF DESTROYED. A DETACHED OUTBUILDING WAS DESTROYED BY A LARGE TREE FALLING ON ITS NORTH SIDE.
5 E Avera [Greene Co, MS] NWS STORM SURVEY reports TORNADO at 23 Feb, 5:32 PM CST -- A BRIEF TORNADO TOUCHDOWN OCCURRED IN THE VICINITY OF SHADY HOLLOW ROAD. A COUPLE OF TREES WITH LARGE BRANCHES WERE SHEARED IN A FORESTED AREA SEVERAL DOZEN YARDS TO THE WEST OF THE ROAD. EF-1 DAMAGE WAS OBSERVED AS NUMEROUS PINE TREES WERE EITHER UPROOTED OR SNAPPED ACROSS THE ROAD. DAMAGE WAS COINCIDENT WITH A TORNADO VORTEX SIGNATURE AND TORNADO DEBRIS SIGNATURE FROM THE MOBILE WSR-88D.
3 SE Avera [Greene Co, MS] NWS STORM SURVEY reports TORNADO at 23 Feb, 5:25 PM CST -- A TORNADO TOUCHED DOWN ALONG MS-63 SOUTHEAST OF THE COMMUNITY OF AVERA. A HOMESTEAD WAS AFFECTED WITH METAL ROOFING MATERIAL FROM A BARN LOFTED INTO AN ADJACENT TREE. A TRAILER WAS ALSO OVERTURNED...WITH A MOTOR VEHICLE MOVED FROM ITS INITIAL POSITION. EF-1 DAMAGE WAS OBSERVED WITH NUMEROUS TREES...MOSTLY PINE...EITHER BLOWN DOWN OR SNAPPED BEFORE THE TORNADO LIFTED JUST ESE OF AVERA.
5 NW Convent [St. James Co, LA] NWS STORM SURVEY reports TORNADO of EF3 at 23 Feb, 3:31 PM CST -- *** 2 FATAL *** THE MAXIMUM WIND AND EF SCALE FOR ASSUMPTION PARISH TO ST JAMES PARISH STRONG TORNADO HAS BEEN INCREASED SLIGHTLY TO LOWER END EF3 TORNADO...VERSUS PREVIOUS UPPER EF2 SCALE RATING...WITH MAXIMUM WIND OF 140 MPH BASED ON EVALUATION OF ADDITIONAL DATA. PATH LENGTH OF 21 MILES AND PATH WIDTH OF 300-350 YD REMAINS THE SAME. PUBLIC INFORMATION STATEMENT WILL BE RELEASED THIS EVENING DESCRIBING THE TORNADOES IN SOUTHEAST LOUISIANA AND SOUTH MISSISSIPPI.
I have questions with regard to the storm. Do storm cells that lead to tornadoes remain discrete entities as they track across the map, or do they dissipate to be replaced by new cells? Does being on land or sea make a difference with regard to affecting these cells as they move and possibly form into tornadoes? How far can a tornado track across the map before it dissipates? How many miles can they move in the form of a tornado? Do they weaken to a thunderstorm and later strengthen into a tornado again? Thanks.
Permit me this small lapse into human emotion. I hate Hurricanes and Tornadoes. Live long and prosper.
SKYSUMMIT President | Director of OperationsAdministrator
The highest tornado threat comes from discrete cells when the environment supports it. You need lift, energy, and sufficient vertical shear so as the storm builds vertically, it will rotate. This can also happen within squall lines, but the highest threat is usually always from the discrete cells. Once developed and matured, if there's nothing to inhibit their inflow, they can go many many many miles...even across entire states as long as the environment can support it. However, say one develops, but another cluster develops to its south...many times those southern cells will stop the inflow into the mature cell and the new cluster takes over.
Supercells can also pulse and cycle. We saw this with a few of them the other day.
The tornado that Pensacola came from a supercell over water. It actually passed close to Grand Isle, Plaquemines Parish then went south of Mobile Bay and moved onshore near Orange Beach. Waterspouts that move over land can often turn into tornadoes and strengthen as long as the atmosphere can support it.
Post by adiabaticcooling on Feb 26, 2016 20:38:33 GMT -6
Fine explanation Sky.
The inflow part is very important. As the humid air expands, you start getting that condensation. Basically releasing the latent heat of vaporization, which is incredibly energetic for water. So the storm can keep the enough heat to keep the temperature gradient high enough for the rapid rise that a tornado needs.
A great example was the storm that produced the Convent tornado. That cluster had two tornado warnings, one for Ascension and one in the south. The northern cell faded from the outflow from the southern cell. As it happened, the Convent tornado monopolized the inflow and picked up intensity.
Anyone who knows better, feel free to correct anything here. I'd rather be wrong and learn.