* GREENSBURG EF5 KILLER TORNADO 2007 *
VIDEO TRIBUTE TO THE VICTIMS & SURVIVORS OF THE 2007 GREENSBURG KANSAS KILLER EF5 TORNADO. A MUST WATCH FOOTAGE WITH WONDERFUL MUSIC TO ACCOMPANY IT.
http://www.youtube.com/watch?v=_5udGnzqlhU
Footage of the 1999 Oklahoma tornado outbreak. 8 minutes of jaw dropping news footage.
http://video.google.com/videoplay?docid=-2000750381881061105&q=May+3+1999+tornado+coverage&ei=f1gjSK6AEoac4gLnvui1AQ
One sentence says it all: "You've got to be #$@*ing kidding meeee!" ....(Chaser Reed Timmer whilst directly under a lowering funnel while filming)
I strongly recommend reading Prof Howard Bluestein's book titled 'Tornado Alley. Monster storms of the Great Plains' avaiable through http://amazon.com/
Oklahoma City holds the the enviable or unenviable record for the most hits by tornadoes. Over 100+ in fact - although this has been updated as season 2007-8 progresses, Huntsville AL comes in second.
Three chasers from their home base in Norman, Oklahoma partnered in 1997 to chase Tornado Alley for severe weather and abroad for hurricanes. Reed Timmer, Joel Taylor and Dean Schoeneck all chase together for tornadoes and severe weather.
Three chasers from their home base in Norman, Oklahoma partnered in 1997 to chase Tornado Alley for severe weather and abroad for hurricanes. Reed Timmer, Joel Taylor and Dean Schoeneck all chase together for tornadoes and severe weather.
Reed Timmer Joel Taylor Dean Shoeneck
(Greensburg 2007 supercell hosting an EF5)
(F5 wedge tornado. Photo courtesty NSSL)
Supercells are the ultimate thunderstorm. Not only are they able to sustain their own longevity by utilizing the conditions to their own benefit, but they are also predatory storms which feed off weaker cells nearby, but also storms ahead of them to become stronger!
Supercells are the ultimate thunderstorm. Not only are they able to sustain their own longevity by utilizing the conditions to their own benefit, but they are also predatory storms which feed off weaker cells nearby, but also storms ahead of them to become stronger!
SUPERCELLS
Okay, time to get into the nitty gritty of supercells and tornadoes. What causes them and what are they. Supercells/storms are catagorized into three main types; HP (high precipitation) LP (low precipitation) and Classic. The obvious answer is always that tornadoes are borne from supercells resulting in... "Cold air moving south from Canada and meeting warm moist air from the Gulf Of Mexico and dry air from the Rockies". This is a gross oversimplification.
Many storms form under these scenarios and almost never come close to producing tornadoes. Storms are found on cold fronts, warm fronts and dry lines anyway. Supercells by their nature are defined as having a persistent rotating updraught, that's the difference. They rotate anticlockwise in the northern hemisphere and clockwise in the southern hemisphere Even more incredible that in reality supercells are rare and tornadoes even rarer - if you can believe that the US has on average 1800 twisters per season!
Many storms form under these scenarios and almost never come close to producing tornadoes. Storms are found on cold fronts, warm fronts and dry lines anyway. Supercells by their nature are defined as having a persistent rotating updraught, that's the difference. They rotate anticlockwise in the northern hemisphere and clockwise in the southern hemisphere Even more incredible that in reality supercells are rare and tornadoes even rarer - if you can believe that the US has on average 1800 twisters per season!
(nighttime shot of tornado courtesy Don Guiliano and Demko per tornadovideos.net)
What makes these movements of air masses favourable is speed and directional shear which cause the production of mesocyclones or the tilting of rotating air vertically to produce a rotating column of air. The animation here shows the funnel picking up debris.
The most destructive and powerful tornadoes are produced from supercells that rotate and show with a well-defined radar circulation called a mesocyclone and a 'hook' echo region. The radar image below shows the pronounced hook at the lower SW corner and mesocyclone. This image is the 2007 Greensburg supercell that produced a killer EF5 tornado)
The drawing below shows everything a supercell incorporates. (courtesy http://spotterguides.us/basic/basic03.htm)
Below are three drawings of what actually happens when a supercell has strong vertical wind shear. The two pictures below show a change in wind direction and an increase in wind speed with height (shear) and horizontal spinning in the lower level winds.
Picture two shows rising air within the thunderstorm updraft tilting the rotating air from horizontal to vertical.
Picture number three shows us the thunderstorm tower and anvil and also the wall cloud and funnel evident. It shows an area of rotation 2-6 miles wide and now extends through much of the storm. Strong and violent tornadoes form in this area. (Drawings courtesy of NSSL/NOAA)
* The photograph below was taken by Reed Timmer whilst chasing a supercell with strong rotation. This photo shows just how the mesocyclone rotates to produce a tornado. (Copyright and credit to tornadovideos.net)
(branched lightning stirke in the early hours of the morning south of Darwin/Copyright stormscapesDarwin.com)
HP supercells
These supercells are storms with lots of rain and often including very large hail which falls from the trailing side of the mesocyclone. Precipitation often envelopes or 'rain wraps' any tornadoes within making identification extremely difficult and dangerous. The region of rotation in HP storms develops in the front flank region of the storm, usually the eastern portion. HP storms often produce extreme, prolonged downbursts, serious flash flooding and very large damaging hail - sometimes baseball sized. Chasing these beasts should be done from a safe distance and cold core punching or into the 'bear's cage' should be avoided at all costs. If there is a tornado inside it you won't know it until its above you.
Outstanding supercell photo courtesy of Kevin Cox/NSSL/NOAA)
LP storms/supercells
are visible with little or no rain evident. These supercells make for excellent tornado observation as usually they are sometimes backlit by sunshine or illumination and condensation wrapping the funnel. Visually very similar in appearance to classic supercells but lacking the heavy precip core. LP cells often exhibit outstanding structure, the main tower often bell shaped with a corkscrew look showing rotation and striations also show circulation around the storm. They are capable of producing tornadoes and large hail. Identification on radar is sometimes difficult so on the spot observations are very important.
LP storms usually occur near a dry line and are sometimes referred hence as dry line storms.
(Photo courtesy of Michael Bath from Australian Severe Weather)
(Kevin Cox/NSSL/NOAA)
Classic supercells exhibit the above also - rain free bases with or without a wall cloud, tail cloud, flanking line, overshooting top and a backsheared anvil - all of which are observed in or near the right rear or southwest portion of the storm. Supercells often last for many hours, ironically tornadoes only last for as little as 10 minutes to over an hour and tornadoes are actually rare per se, not all supercells produce them. This however should not be taken as actual fact because very large violent supercells can produce more than one vortex and even rarer is a tornado rotating anticyclonically, that is, rotating clockwise instead of counterclockwise!!!!
Photo and graphics courtesy NOAA/NSSL
(Satellite photo of a massive supercell located 300+km SE of Darwin. This supercell was as a result of a deepening tropical low passing over Darwin in March 2007 and this storm produced a tornado to high F2 or F3 scale. The tropical low eventually became severe TC George which tracked thousands of miles to Western Australia and then eventually made landfall at Port Hedland. Three people lost their lives and many more were injured.)
Different types of supercells are favourable in different areas in the US. LP supercells primarily occur in the Lee of the Rockies, HP supercells are common in the Eastern Great Plains and eastward. Classic supercells are most common in the Great Plains. Low level moisture and the value of precipitable water strongly influence and determine the type of supercell and how severe it becomes.
(photo of thunderstorm north of Darwin City enhanced by wind shear which produced a wall cloud underneath - this was ahead of a severe separate storm packing 90km/h winds)
TORNADO INFORMATION, HISTORICAL EVENTS, MYTHS AND FACTS!
This topic is a real passion (probably because I haven't seen one!) and I'll include heaps of info including charts, photos, scales, radar imagery, WRF wind charts and more!
(Lakeview TX tornado shot courtesy NSSL)
Tornado (Fujita) F- scale & adopted EF-scale.
Firstly, it must be made aware that just because a tornado may be a 'rope' version does not mean that it cannot be a killer and have the same damaging winds as an EF4. Likewise for an EF5 may be huge but not have a damage pattern of one but of an EF2. Damage is not dependant on what the tornado looks like, it is the winds being produced and WHAT DEBRIS in that wind hits.
A lot depends on the dwelling's construction and the type of building it is and in reality wind scale measurements are guesswork, none of which have been tested scientifically at all. Dr T Theodore Fujita developed a damage scale (Fujita 1971, Fujita and Pearson 1973) for winds, including tornadoes which was supposed to relate the degree of damage to the intensity of the wind.
The F-scale was the result, It should be noted that the old F-scale should not be used anymore because of the newly adopted EF scale version now in use since February 2007 - although previous tornadoes will not have their F-scale rating changed to suit the EF version. The F-scale winds were arbitrarily attached to the damage cale based on a 12 step mathematical interpolation between the hurricane critera of the Beaufort wind scale and the threshold of Mach 1 (738 mph)
The F-scale actually peaks at F12 (Mach 1), only F1 to F5 are used with F0 attached for tornadoes of winds weaker than hurricane force. There is no F6 scale, as most F4-5 tornadoes create incredible winds/damage anyhow. (photo courtesy NSSL/NOAA) As far as anything being rated F6 - wind speeds rated at 318 mph would be rated an F5 anyhow since F5 is the most intense possible damage level.
On the enhanced F-scale there is no such thing as an EF6. Here's the Fujita tornado scale and the Enhanced Fujita scale:
FUJITA TORNADO SCALE
F0 - Fastest 1/4 mile speed 40 -70 mph / 3 second gust @ 45-78 mph.
F1 - 73 - 112 mph / 3 second gust @ 79 - 117.
F2 - 113 - 157 mph / 3 second gust @ 118 - 161.
F3 - 158 - 206 mph / 3 second gust @ 162 - 209.
F4 - 207 - 260 mph / 3 second gust @ 210 -261
F5 - 261 - 318 mph / 3 second gust @ 262 - 317
F6 - greater than 319 mph.
F1 - 73 - 112 mph / 3 second gust @ 79 - 117.
F2 - 113 - 157 mph / 3 second gust @ 118 - 161.
F3 - 158 - 206 mph / 3 second gust @ 162 - 209.
F4 - 207 - 260 mph / 3 second gust @ 210 -261
F5 - 261 - 318 mph / 3 second gust @ 262 - 317
F6 - greater than 319 mph.
ENHANCED FUJITA SCALE
EF 0 - 3 second gust @ 65 - 85 mph
EF 1 - 3 second gust @ 86 - 110
EF 2 - 3 second gust @ 111 - 135
EF 3 - 3 second gust @ 136 - 165
EF 4 - 3 second gust @ 166 - 200
EF 5 - 3 second gust over 200.
EF 1 - 3 second gust @ 86 - 110
EF 2 - 3 second gust @ 111 - 135
EF 3 - 3 second gust @ 136 - 165
EF 4 - 3 second gust @ 166 - 200
EF 5 - 3 second gust over 200.
It's important to note that the EF scale still is a set of wind estimates and not measurements based on damage. It uses three second gusts estimated at the point of damage based on a judgement of 8 levels to a set of 28 indicators in relation to structural dwellings such as barns down to trees. The three second gust is not the same wind speed as in standard surface observations. Standard measurements are taken my weather stations in open areas using a directly measured 'one minute mile' speed.
(photo NSSL)
For properties of supercells here are some charts, graphs etc that give some idea of the weather conditions suitable for supercell formation and possible tornadoes. Whilst supercells may develop from these systems it must be remembered that tornadoes may not actually form from them - atmospheric conditions change all the time during the day and night!
Sounding charts are vertical profiles of temperature, dewpoint and wind in the atmosphere or they are commonly known amongst meteorologists as Radiosondes (weather balloons). Hodographs are graphical representations of wind speed and direction with height in the atmosphere. Meteorologtists use hodographs to monitor the environment and determine if the potential exists for thunderstorms to rotate (supercells)(find out more on supercells)
Hodographs display different heights in millibars as surface winds up to 700mb are blue, from 700 through to 300mb are yellow and the winds above 300mb are in white. The dots are the actual wind velocities (the direction and speed). The numbers by the dot represent the pressure level at which this velocity was located - ie: 7 = 700mb, 3 = 300mb. Colours may vary but an example of a hodograph is further down .
Hodographs display different heights in millibars as surface winds up to 700mb are blue, from 700 through to 300mb are yellow and the winds above 300mb are in white. The dots are the actual wind velocities (the direction and speed). The numbers by the dot represent the pressure level at which this velocity was located - ie: 7 = 700mb, 3 = 300mb. Colours may vary but an example of a hodograph is further down .
Generally 'standard storms or pulse storms have an erratic movement on the graph, multicells have a defined gradual increased line to the right with horizontal movement. Supercells have a more horizontal lineage to the right without any erratic behaviour. Whilst all show increased rotation (shear) and a gradual increase in speed, multicells and supercells have significant speed increases along a broad path in their motion.
Diagram of converging cold and warm fronts with low pressure areas - triple point scenario. An occluded front is formed during the process of cyclogenesis when a cold front overtakes a warm front. The cold and warm fronts curve naturally poleward into the point of occlusion, which is also known as the triple point in meteorology. Supercells are often tornadic with these systems.
(below is credited to John Davies/Tornadovideos.net)
Surface, CAPE, 500mb and 850 mb wind stream chart from Texas area on 4 May 2007. Note deep low area of 993mb. This low pressure area and associated wind streams would be conducive for supercell formation.
(below is a past Skew-T shounding from Mississippi in which an F3 tornado grounded)
(Below is a Dopplar radar storm velocity wind image.)
The hodograph shows storm motion from the west at 15kts (remembering that supercells tend to be 'right movers'). The figures in the colum represent direction and wind speed at the different heights.
Courtesy Matthew J Bunkers NWS
As can be seen from just these charts etcetera, there's a hell of a lot of information chasers and meteorologists have to consider! Even when all the atmospheric conditions seem perfect, the CAPE, CIN, shear, WRF models - it can all go to blue sky if something changes. Supercells are no different.
All storms are dependant on the 'right' conditions for the right amount of time. A weakening of shear, a strengthening of upper winds, cold inflow from cold pools - over a period of time what looks like a grandios storm could be a fizzer - but that's what chasing is all about. Education and observation.
(two charts courtesy of NWS/NSSL)
This incredible chart below shows a 100mb pressure drop as it passed over a pressure sensor. This is a fantastic example of the forces around and within a tornado. 100mb drop in less than 2 minutes!
SIGNIFICANT HISTORICAL TORNADO OUTBREAKS:
In this section I've put some info on some of the more historical tornado events that have happened over the years. In review also I'll include events from 2007 as these will be remembered as historical with well over 150 tornadoes sighted to date (May 2007) and more no doubt by season's end. Not only were there many killed but whole communities wiped out by killer storms.
Why some seasons are worse than others is probably anyone's guess, whether they occur in seasonal cycles or if it's just plain atmospheric conditions that meet the criteria for severe weather on a sustained scale. One thing is for sure, outbreaks continue to occur when we least expect them. If tornadoes are actually 'rare' with supercell formation then these must surely remind us that significant storm systems can produce killer tornadoes on a wide scale and not are not always localised events on the plains or elswhere.
The Oklahoma City tornadoes of June 13 1998 and October 4 1998.
(photos & graphs courtesy of NOAA/NSSL/NWS Norman)
9 separate tornadoes touched down in central and western Oklahoma on 13 June 1998. Thunderstorms developed during the afternoon and quickly grew to supercell status and tracked eastward into the central sections of the state. One initial storm was so powerful it spawned an amazing 7 individual tornadoes as it tracked through Oklahoma from the Canadian County. Although so many tornadoes were produced only two were rated F2, four rated F0 and three rated F1. Which probably proves that not every 'mother of all supercells' produces just one giant F4-5. Thankfully there were no fatalities during this outbreak although there were many injuries (21) reported in Oklahoma County. Injuries that were sustained were confined to the Frontier City theme park from an F2 tornado when it crossed Interstate 35.
(separate Oklahoma tornado path in 1999)
The tornadoes developed near a dry line and the most significant cell developed at around 4pm CST. The majority of storms spawned tornadoes between 4:45pm to 8:23pm from Blaine County right across to El Reno, in the Canadian County, North Oklahoma City and Northeast OKC. The general wind speeds were from 73 - 157mph within the F0 to F2 range.
(Okalhoma 1999 tornadic supercells)
(below is a past Skew-T shounding from Mississippi in which an F3 tornado grounded)
(Below is a Dopplar radar storm velocity wind image.)
The hodograph shows storm motion from the west at 15kts (remembering that supercells tend to be 'right movers'). The figures in the colum represent direction and wind speed at the different heights.
Courtesy Matthew J Bunkers NWS
As can be seen from just these charts etcetera, there's a hell of a lot of information chasers and meteorologists have to consider! Even when all the atmospheric conditions seem perfect, the CAPE, CIN, shear, WRF models - it can all go to blue sky if something changes. Supercells are no different.
All storms are dependant on the 'right' conditions for the right amount of time. A weakening of shear, a strengthening of upper winds, cold inflow from cold pools - over a period of time what looks like a grandios storm could be a fizzer - but that's what chasing is all about. Education and observation.
(two charts courtesy of NWS/NSSL)
This incredible chart below shows a 100mb pressure drop as it passed over a pressure sensor. This is a fantastic example of the forces around and within a tornado. 100mb drop in less than 2 minutes!
SIGNIFICANT HISTORICAL TORNADO OUTBREAKS:In this section I've put some info on some of the more historical tornado events that have happened over the years. In review also I'll include events from 2007 as these will be remembered as historical with well over 150 tornadoes sighted to date (May 2007) and more no doubt by season's end. Not only were there many killed but whole communities wiped out by killer storms.
Why some seasons are worse than others is probably anyone's guess, whether they occur in seasonal cycles or if it's just plain atmospheric conditions that meet the criteria for severe weather on a sustained scale. One thing is for sure, outbreaks continue to occur when we least expect them. If tornadoes are actually 'rare' with supercell formation then these must surely remind us that significant storm systems can produce killer tornadoes on a wide scale and not are not always localised events on the plains or elswhere.
The Oklahoma City tornadoes of June 13 1998 and October 4 1998.
(photos & graphs courtesy of NOAA/NSSL/NWS Norman)
9 separate tornadoes touched down in central and western Oklahoma on 13 June 1998. Thunderstorms developed during the afternoon and quickly grew to supercell status and tracked eastward into the central sections of the state. One initial storm was so powerful it spawned an amazing 7 individual tornadoes as it tracked through Oklahoma from the Canadian County. Although so many tornadoes were produced only two were rated F2, four rated F0 and three rated F1. Which probably proves that not every 'mother of all supercells' produces just one giant F4-5. Thankfully there were no fatalities during this outbreak although there were many injuries (21) reported in Oklahoma County. Injuries that were sustained were confined to the Frontier City theme park from an F2 tornado when it crossed Interstate 35.
(separate Oklahoma tornado path in 1999)
The tornadoes developed near a dry line and the most significant cell developed at around 4pm CST. The majority of storms spawned tornadoes between 4:45pm to 8:23pm from Blaine County right across to El Reno, in the Canadian County, North Oklahoma City and Northeast OKC. The general wind speeds were from 73 - 157mph within the F0 to F2 range.
(Okalhoma 1999 tornadic supercells)
List of tornadoes which occurred in
central and western Oklahoma on 6/13/1998:
|
OKLAHOMA TORNADOES OCT 4, 1998
Map of Tornadoes in the
Immediate Oklahoma City Area:
At least 19 tornadoes struck the portion of Oklahoma served by the NWS Norman office. These include tornadoes in the cities of Moore and Shawnee. Eight more other tornadoes touched down in northeastern Oklahoma in the area served by the NWS office in Tulsa.
| Tornado Timeline on October 4, 1998 | |||||
|---|---|---|---|---|---|
| Tornado ID |
Time | County | Location | Intensity | Length (miles) |
| A1 | 3:25-3:43 | Woods/Alfalfa | 11 SSW Dacoma - 4 NW of Carmen | F2 | ~10 miles |
| A2 | 4:05 | Alfalfa | 5 SE Cherokee | F0 | short |
| A3 | 5:04 | Grant | 5 W Medford | F0 | short |
| B1 | 5:38-5:41 | Blaine | 8 SW - 6 SW Watonga | F0 | 1.5 miles |
| B2 | 5:50-6:12 | Blaine | 3 SW Watonga - 9 ENE Watonga | F2 | 12 miles |
| C1 | 6:14 | Comanche | Just north of Lake Lawtonka (About 5 N Medicine Park) | F0 | short |
| B3 | 6:28-6:42 | Kingfisher | 6 SW Dover - 2 SE Dover | F1 | 7 miles |
| B4 | 6:47-6:56 | Payne/Noble | Lake Carl Blackwell - just east of Lake McMurtry (10 W Stillwater - 6 NW Stillwater) | F1 | 6 miles |
| C2 | 6:45 | Caddo | 1 NE Cyril | F0 | 1/2 mile |
| C3 | 6:54-6:55 | Grady | 9 WSW Ninnekah - 7 WSW Ninnekah | F2 | 2 miles |
| C4 | 8:15-8:21 | Grady/McClain | 4 NW Blanchard - just SW of Newcastle | F2 | 5 miles |
| C5 | 8:26-8:28 | McClain/Cleveland | Extreme north Newcastle into extreme SW OKC | F0 | 1.5 miles |
| C6 | 8:34-8:41 | Cleveland | Moore | F2 | 3 miles |
| C7 | 9:37-9:40 | Lincoln | 4 SE Meeker - 5 E Meeker | F2 | 3 miles |
| C8 | 9:45-9:52 | Lincoln | 7 W Prague - 4 NW Prague | F2 | 6 miles |
| D1 | 9:50-9:55 | Pottawatomie | NW Shawnee | F1 | 3 miles |
| C9 | 9:52-10:08 | Lincoln | 6 NW Prague - 7 NNE Prague | F1 | 8 miles |
| D2 | 9:58-10:00 | Pottawatomie | SE Shawnee | F1 | 2 miles |
| D3 | 10:08-10:25 | Seminole/ Pottawatomie | 5 WNW of Little - Center View - 3 SE Prague | F3 | 10 miles |
The Red River Valley tornado outbreak of April 10, 1979
No-one would have believed that by day's end a whole township would be destroyed. Three specific tornadoes out of the observed 13 that struck on three separate paths side-by-side across a large area of populated counties caused extreme damage and killed a total of 56 people, injured over 1900 people, hospitalized 259. Destroyed over 3,000 dwellings, impacted major structural damage to over 1000 homes and minor damage to over 2000 structures. 139 mobile homes destroyed and over 1300 family units destroyed. Families suffering losses totalled over 7,500. These figures include 12 counties in Texas, Clay, Foard, Witchita, Wilbarger, Oklahoma, Cleveland, Comanche, Cotton, Jefferson, Pottawtomie, Stephens and Tillman.
(courtesy of NSSL/NOAA)
The tornadoes were giants. One tracked a continuous ground path over 35 miles or longer and the only it was not grounded was during formation and dissipation. One tornado had a damage path 1 mile wide which is still the biggest on record. The damage bill was in excess of $63 million.
(below is track path map made by Dr Fujita/courtesy NSSL - note numbers indicating each tornado's rating)
Below are some images from different areas affected by these storms.
(Haunting photo that really depicts the innocence of youth. What we know today of storm structure would have us in disbelief of what this photo shows)
(Storm track of Wichita Falls supercell/vehicles scattered like toys from the Seymour TX tornado April 10 1979 This link will take you to all the tornado images from various people. Worth a view at http://www.srh.noaa.gov/oun/wxevents/19790410/wichitafalls.php
(All photos courtesy NSSL)
(second photo of Vernon '79 tornado courtesy Dennis Lingnau) 
)
The 1925 Tri-state tornado outbreak. In 1925 weather records and observation techniques were obviously not what they are today and given our knowledge of such storms today reminds us this outbreak surely must rate as truly significant.
On March 18 looking at the weather conditions one could assume there was a moderate to severe risk for tornado formation! Here's a brief summation of the weather ingredients courtesy of the NOAA/NWS report;
'During the morning a surface low pressure area over northwest Arkansas and southwest Missouri tracked across southeast Missouri, southern Illinois and southwest Indiana during the day, reaching eastern Indiana that evening. Extending east from the low was a warm front with a cold front trailing to the southwest. as the low tracked northeast during the day its associated warm front advanced north allowing warm moist air from the Gulf of Mexico to infiltrate the Tri-state area. In fact, temperatures that started out in the 50s during the morning reached the 60s over most of the tornado track by 1pm in teh area of Cairo, Illinois by 4pm.
We can assume from that that the lifting mechanism was in place! (tornado track map courtesy John W Wilson, 'Illinois Tornadoes') What can also be inferred also that there must have been very good upper level support given the fact that the tornado traveled at speeds of 60 to 70 mph along most of its path, we can safely assume that perhaps 100 knot upper level jet max was nosing into the area from the west-southwest. With veering winds (south at the surface becoming west-southwest aloft) wind shear was also present to help initiate the storm's rotation. There must have been decent instability as well with warm air advection at the surface and probably cold air advection in the upper levels.
( NOAA/NSSL photo)
The damage and death toll was incredible - hopefully never to be repeated, the facts below are startling!
Photos and report from resident in Jarrell from that destructive tornado that destroyed a community and several lives. http://www.tagworld.com/sklee/World/MyWeb.aspx?page=5dbd8664-b7ae-4c6b-b6e4-00536b1647c0
FACTS: 3 states affected (Missouri, lllinois, Indiana) 13 counties affected. 19+ communities affected. 219 mile path length!!! Accounts of a mile wide path width. 3 hours of continuous devastation. 1:01pm - tornado touched down 3 miles NNW of Ellington, Missouri. 4:30pm tornado dissipated about 3 miles SW of Petersburg, Indiana. 62 mph average speed. 73 mph record speed between Gorham and Murphysboro. F5 tornado with winds perhaps in excess of 300mph. 28.87" lowest pressure measured on a barograph trace the the Old Ben Coal Mine in west Frankfort, Illinios. 695 deaths. 234 deaths in Murphysboro. 33 deaths at the De Soto school (only bombings and gas explosions have taken higher school tolls) 2,027 injured 15,000 homes destroyed.
THE MAY 4 2007 GREENSBURG EF5 TORNADO.
On Friday night at around 7:12pm the town of Greensburg in the Comanche/Kiowa County was obliterated by an EF5, 1.7 mile wide tornado. 17 people lost their lives.
(NASA/GOES satellite photo of storms affecting Greensburg)
WEATHER SUMMARY OF THIS EVENT:
The Storm Prediction Centre issued a moderate risk across parts of Kansas, Oklahoma and Nebraska on May 4 while temps were in the mid to high 80F. A powerful low pressure system developed across the southern Rockies and a warm front provided additonal moisture coming from the Gulf of Mexico and with the increasing amounts of instability across much of the region. A dry line which divides dry and humid air was positioned near the areas affected by the system. This scenerio is a chasers dream, unfortunately it also is ripe for violent supercells, high winds and large hail - and tornadoes.
On May 5 the same centre issued a high risk for Central Kansas and central nebraska wehre additional destructive tornadoes were possible. If that wasn't enough, softball sized hail, high winds and flooding were possible. (estimated wind of 145km/h was reported!) On May 6 the centre issued a moderate risk for severe storms over parts of Central Kansas and northwestern Oklahoma. At least 10 MORE tornadoes were reported that day in the same general area as the preceding two days! A slight risk was issued but no tornadoes were reported on May 7. The days of tornado outbreaks were May 4-6 2007. Total duration was 48 hours. Maximum rated tornado grounded EF5. Total tornadoes sighted - and incredible 72 confirmed, 143 reported. Fatalities 14. Most of the Central United States was affected.
If all this wasn't enough, the outbreak did not end there; a total of 91 tornadoes were reported on May 5 in the same area. Most were in open country but 1 fatality was reported in Ottawa County, Kansas near a county lake. 10 more tornadoes were reported on May 6 in the same general area. No tornadoes took place after May 6.
(NSSL/NWS radar image and loop of the specific supercell. Note at the lower SW corner the area where the tornado formed showing the mesocyclone rotation in purple almost on top of Greensburg. Looped radar image is a must see view on the NWS/NSSL sites as it displays the violent pronounced rotation of the 'hook' echo. Frightening.
Total destruction of the community and many photos can be seen here from residents and professional chasers http://www.greensburggreentown.org/photos.
Manitoba, Canada F5 tornado June 22 2007.
(all tornado photos courtesy of tornadovideos.net and are subject to copyright)
(excerpts from http://www.wikipedia.com/)
On June 22 2007, an F5 struck the town of Elie Manitoba, 40 kilometres (25 miles) west of Winnipeg While several houses were leveled, no one was injured or killed by the tornado.
The tornado touched down north of the Trans-Canada highway around 6:30 pm CDT (2330 UTC) and slowly moved southeast where it picked up a tracker-trailer before it headed south and severely damaged the town's 4 mill causing over $1 million in damage. After hitting the flour mill it headed southeast towards Elie, where it destroyed four houses, flipped over cars, and even tossed one home owner's Chrysler Fifth Avenue onto their neighbour's roof. The tornado lingered over the same area of Elie for approximately four minutes before it cut sharply to the south and rapidly dissipated. The tornado traveled about 6 km (3.7 miles) and was 300 m (330 yds) wide at its widest during its 40 minute lifespan. The tornado repeatedly struck essentially the same area of town, destroying most of the structures and vehicles in the area.
If the tornado had continued along its southeast track, it would have hit the main part of town. At the same time as the Elie tornado, another tornado was touching down close to nearby Oakville. Two tornadoes not far from each other at the same time was a rare occurrence for the people watching the news that evening. There were reports of 8 touchdowns in Manitoba during that day. The people in Elie were prepared and took the necessary precautions, during this situation.
The following day, Environment Canada sent out a storm damage survey team to assess the damage caused by the tornado. On Sept 18, 2007, the tornado was upgraded to F5 on the Fujita scale from the original F4, as winds were determined to be between 420 km/h and 515 km/h (261 and 318 mph), based on video analysis of the tornado and reassessment of the damage. This was the first tornado in Canada to be officially rated as such, making it the strongest confirmed tornado in Canadian history, and only the second F5 tornado ever since 1999. (the other being in Greensburg, Kansas on May 4 2007). It should be noted that Canada has not adopted the Enhanced Fujita scale yet; if used, the equivalent EF5 rating would have winds in excess of 200 mph (320 km/h).
Weather Conditions Leading Up To The Tornado
The synoptic situation on June 22 was conducive to a major severe weather event in southern Manitoba. A low pressure system came in from Saskatchewan through the day, and then moved over southern Manitoba throughout the evening. A warm front was positioned north of Elie for much of the day with a trailing cold front residing west of Elie near the Lake Manitoba basin southwest through southeast Saskatchewan. A lake breeze boundary was also present south of Lake Manitoba.
(NSSL photo of a wedge tornado)
Very warm air was situated over Southern Manitoba that day as temperatures climbed into the high 20s°C (low 80s°F). The humidity was also uncomfortably high, with dewpoints ranging from 18-22°C (65-72°F). Directional and speed shear were present as well as high helicity values. These conditions were favourable for supercells which are thunderstorms with rotating updrafts, and they developed within the warm sector located in the Red River Valley and areas farther west. The situation was exacerbated by the presence of the lake breeze boundary because the atmosphere was capped through much of the day with little in the way of a trigger. This boundary provided the focus for storms to develop rapidly and become severe, given the high instability present.
Don't ever believe that strong winds can't kill you. Even a small CAT1 cyclone can whip up winds that can hurl objects around. This record was impaled into a tree during the Tri-State tornado outbreak in the USA. It should serve as a visual warning to stay indoors during severe weather events.
Here's the current average tornado data from the Severe Prediction Centre in the USA thus far. Does not look to positive to date!
