1 Year AGO OCt. 18th 2007 Tornado Outbreak

From mine MY Space Blog

Some Past Tornado numbers for West Ky. ( for lack of onfusion west ky is the counties in ky ocvered by nws paduach from Muhlenburg, Todd, Mclean, Daviess west.

May 4th 2003- 11

May 6th 2003- 10

Great Memorial Day Weekend outbreak- 6

November 15th 2002- 6

October 18th Act I 2004- 1

September 22-23rd 2006- 5

October 18th Act II - 15

THE EF SCALE IS AS FOLLOWS:

EF0- 65 TO 85MPH

EF1- 85 TO 109MPH

EF2- 110-137MPH

EF3- 138-167MPH

EF4- 168-199MPH

EF5- 200MPH+

On October 17th atmospheric conditions appeared ripe for a nasty night and a nasty day on October 18th. A powerful low at it;s deepest point it was around 980mb was moving from Nebraska to Iowa. A strong cold front with powerful forcing was extending all the way down to the gulf coast. Following the actual cold front an shortwave came though on the night of the 17th and early morning hours of the 18th.

On October 18th the day 1 outlook but all of west ky and later on inculded all of middle Tenneesee in a Moderate Risk of severe weather in every outlook. Henderosn/Owensburo areas were in the Moderate Risk as early as the Day 3 outlook this may be one of the first times ever that Western Ky was included in a Moderate Risk on Day 3.

The shear was amazing form the storng low in Iowa. Instablity was intially a problem. As the day went on a dry slot with a cap persisted across Western Ky from 9am till it started to break around 3 and by 3:45pm the cap was gone and supercells started to form. Also instablity was a lot high than expected with CAPE values of 1500 to 2000 j/kg. With this setup I knew that even any storm tap into the shear will rotate and have very good torando potenial.

This resulted in supercells later forming into a serial Derecho or a squall line with supercells that is pareall to the mean wind. This supercell to line connection resembles the Ocotber 24th 2001 severe weather event very closely. Except there are a few differences there was a little more intense forcing on 10/24/01 but on 10/18/07 there was more instablity to make up for lack of forcing. The line of supercells which was broken across west ky formed a complete line and charged for Middle Tenneesee knocking out power across Metro Nashville and damgaing many trees and even a few buildings.

NATIONAL OUTLOOK: A powerful low 980 traveled across Iowa. Tornados spawned from Michigan to even Penascola FLorida got hit hard. The day before Paris MO suffered 2 deaths from a night torando that hit in the area. Nationally this is the biggest tornado outbreak in Ocotber since October 24th 2001. On October 24th 2001 an almost silmar situation featured about 500 reports of severe weather and tornadoes from Michigan to Alabama. Including a torando in Manchester Tenneesee.

LOCAL OUTLOOK ( WESTERN KENTUCKY AND PARTS OF TENNEESEE) Locally a historic tornado outbreak occured in Western Kentucky. In the 22 counties in western kentucky 11 tornadoes occured. This amount is the most since May 4th 2003 when 11 tornadoes also occured plus more on the overnight hours of May 4th and 5th in Middle Tenneesee making it the 8th largest torando outbreak in Middle Tenneesee. This looking back at records will not be the most torandoes to ever occur at Ocotber in west ky or the biggest October Tornado outbreak but the biggest fall outbreak ever for the 22 counties in West Kentucky. But since the ansty November 2005 tornado outbreaks that hit west ky the whole area was prepared for a fall outbreak so therefore that was one of the facotrs that led to no deaths being recorded in Western Kentucky even though an EF3 hit Owensburo Ky. The EF3 came from a powerful supercell with a hisotry of tornadoes in Webster County including Dixon and Sebree. Dixon KY also got hit in the Sept 22nd-23rd 2006 Tornado Outbreak more about that one on an earlier blog. Daviess County got 4 torando paths in thier county alone. One of my radar pics on my fall pics section has the indivual supercell involved with the ef-1 and ef-2 around 6pm. The Storm Mode with supercells at first. The supercells formed in Livingston and Crittenden County and one formed in Daviess COunty. At first even tohugh the storms spawned tornado warnings they didnt produce torandoes at least not at the time. At 6pm a powerful supercell with some reports of a funnel cloud/torando in Clay Ky in webster county moved into Daviess County which two of the tornadoes occured east of Owensburo. Then a line of storms and supercells formed again in far western ky. One quick supercell dropped a brief tornado in west central Graves County. Then a line eventually becoming a SERIAL DERECHO formed decorated with supercells esp in Western KY. The powerful line chargerd the lakes cancelled a regional soccer tournament and destroyed a house. Then the biggest part of the outbreak happened supercells ythat were at the edge of line from near Murray to Providence Ky and moved northeast strengthed a produced tornadoes. Trigg County suffered two tornadoes one Ef-1 and one EF-2 this heavily damaged parts of the Lakes area and the Lake Barkley State Park. And rural areas of southeastern Trigg County. A powerful supercell went from Southerneastern Caldwell into Northwestern Chrisitan near Dawson Spring and caused 1 injury to a person in a moblie home which closed state road 109. Also at the time one of theo ther supercells moved from Dixon to and tohugh downtown Owensburo producing an Ef2 in Webster County, Ef2 damage in Mclean Conty. 8 injuries occured in Owensburo proper and over a million dollars esp to a church which was destroyed and several homes in Downtown Owensburo the Tornado produced 155mph winds. After the supercells the line caught up to most of the supercells in west/centrla Ky and Middle Tenneesee but there was some rotation in the Derecho including additional torandoes in Central Kentucky. Also widespread damgaing winds including 73mph wind gust in Nashville Metro and widespread reprots of trees down some on homes causing damage. Also scattered power outages occured in Middle Tenneesee.

COMPARING 2 OCOTBER OUTBREAKS

OCTOBER 24TH 2001

* A High risk Day

* All Straight Line WInd Damage in West KY

* Several Injuries in West KY

* Contained a powerful low pressure system in Southern Wisconsion

* Very Strong Forcing involved

* Temps in the upper 70's to around 80

* CAPE VALUES 1000j/kg to 1500j/kg

* Very strong shear

* Rain the day and night before also thoughout the day before the squall line

* Features a Serial Derecho across Kentucky and Tenneesee

OCTOBER 18th 2007

* A Moderate Risk Day

* Powerful Low in Iowa

* Strong Forcing

* Strong Shear

* Cape Values from 1750 to 2000 j/kg

* Rain the day before Temps in the low to Mid 80's

* Features a Serial Derecho across Kentucky and Tenneesee

* The biggest Fall Tornado outbreak in west Ky as far as number of torandoes

* Did cause several injuries

TAKE HOME LESSONS FOR OCTOBER 18th 2007

* Never Underestimate severe potenial with there is amazing wind shear present.

* Strong Shear plus 1500j/kg + CAPE VALUES in the Fall or Winter Time screams potenial for a fall severe weather and torando outbreak.

* Discrete Supercells can and well happen in Fall outbreaks if condtions are right. In some cases storm mode in a fall outbreak is not all that different form a spring outbreak even though there are some differences.

* If there is a planned event like a soccer tourment on a MODERATE or HIGH risk day they sohuld postpone it to another date. You should never try a risk by putting people away from family, friends and shelter for an event the could require the following to save lives.

* We got smarter about Fall Severe Weather Awareness as a whole in the community and across West KY. We know that torandoes and damging winds aren;t just spring things and that they can occur anytime 24/7 and 365 and 1/4 days a year. Emergancy Mangement spotters and everyone else including citizens did an amazinn job during this event to save lives and help clean up the damage the storms left.