Storms Still Moving East

At 4:20 PM, heavy downpours with some occasional wind gusts to 35 MPH were still moving east across the Tennessee Valley, and a Tornado Watch in effect until 8 PM has been cancelled for the following counties in North Alabama: Cullman, Limestone and Morgan.

There is still potential for some heavy storms over DeKalb, Jackson, Cherokee, and Etowah Counties in North Alabama. That’s where we have at least some mixture of instability and wind shear. The graphic below shows effective helicity in the lowest one kilometer of the atmosphere; note the higher values near the Georgia border and up through eastern Middle Tennessee and East Tennessee. This helicity is the wind shear we talk about that helps get storms rotating; higher values (over 400) are often more alarming than these lower-end values of 100-300 over the eastern Tennessee Valley.

The tornado watch will continue for Madison, Marshall, Jackson, DeKalb, Lincoln, Franklin (TN), Bedford (TN), Giles (TN), Moore (TN) and Lawrence (TN) until 8 PM. We here watching it for you!

If you have plans for the rest of the evening, the threat is over west of Interstate 65 through The Shoals and over toward the Mississippi border.

Storm systems like this one usually produce smaller, weaker severe weather events. A small EF-0 tornado did occur in Coosa County, Alabama this morning; here’s the write up from NWS Birmingham:

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
359 PM CDT MON OCT 1 2012

…NWS DAMAGE SURVEY FOR 10/01/12 TORNADO EVENT…

…EARLY MORNING TORNADO CONFIRMED IN COOSA COUNTY…

.OVERVIEW…A WARM FRONT LIFTING NORTHWARD AHEAD OF A SURFACE LOW
PRESSURE SYSTEM TRACKING FROM THE GULF OF MEXICO TO NORTHWESTERN
ALABAMA PROVIDED SUFFICIENT LIFT AND SHEAR FOR AN ISOLATED BRIEF
TORNADO TO FORM ALONG THE WARM FRONT IN THE EARLY MORNING HOURS.

.PENTONVILLE TORNADO…

RATING: EF-0
ESTIMATED PEAK WIND: 75-85 MPH
PATH LENGTH /STATUTE/: 0.5 MILES
PATH WIDTH /MAXIMUM/: 150 YARDS
FATALITIES: NONE
INJURIES: NONE

START DATE: OCT 01 2012
START TIME: 447 AM CDT
START LOCATION: 0.9 MI SW OF PENTONVILLE
START LAT/LON: 32.8089 -86.2405

END DATE: OCT 01 2012
END TIME: 449 AM CDT
END LOCATION: 0.5 MI W OF PENTONVILLE
END_LAT/LON: 32.8157 -86.2367

SURVEY SUMMARY:

NATIONAL WEATHER SERVICE METEOROLOGISTS SURVEYED STORM DAMAGE
REPORTS IN ELMORE AND COOSA COUNTIES AND DETERMINED THAT AN EF-0
TORNADO CAUSED DAMAGE IN COOSA COUNTY. THE DAMAGE IN ELMORE COUNTY
WAS MINIMAL AND SPARSE…MAINLY IN THE FORM OF FALLEN ROTTED
TREES. IN COOSA COUNTY…THE TORNADO INITIALLY TOUCHED DOWN JUST
EAST OF COUNTY ROAD (CR) 45 SOUTH OF SHADY GROVE CHURCH IN A THIN
STAND OF TREES BETWEEN THE ROAD AND A PASTURE. IT PROCEEDED TO THE
NORTH-NORTHEAST AT ABOUT 30 MPH…UPROOTING TREES IN A CONVERGENT
PATTERN IN THE VICINITY OF SHADY GROVE CEMETERY. IT UPROOTED 3
LARGE PINES AS IT CROSSED CR 14…THEN DAMAGING A SMALL BARN AND
OUT BUILDINGS DUE TO UPROOTED OAK TREES BEFORE MOVING INTO A
HEAVILY WOODED AREA. LARGE HARDWOOD TREES WERE UPROOTED
SPORADICALLY ALONG THE PATH…WITH ONE AREA OF CONCENTRATED DAMAGE
DEEP IN THE WOODS. THE TORNADO THEN WEAKENED RAPIDLY AND
DISSIPATED OVER WOODED LAND BEFORE THE THUNDERSTORM CROSSED CR 8.

SPECIAL THANKS TO MR. RICK CARDWELL FOR HIS ASSISTANCE IN
CONDUCTING THIS DAMAGE SURVEY.

A MAJOR CONTRIBUTION TO THE SUCCESS OF OUR SEVERE WEATHER WARNING
PROGRAM IS THE RECEIPT OF STORM REPORTS FROM ALL OUR CUSTOMERS AND
PARTNERS. IF YOU WITNESSED OR ARE AWARE OF ANY STORM DAMAGE DUE TO
HIGH WINDS OR TORNADOES…PLEASE CONTACT YOUR LOCAL EMERGENCY
MANAGEMENT OFFICE…OR CALL OUR STORM REPORTING HOTLINE AT
1-800-856-0758.

NOTE:
THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO
CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN NWS
STORM DATA.

Be sure to join us on WHNT News 19 at 5, 6 and 6:30 for the latest on the weather situation. And in case you didn’t know or had forgotten, you can always watch WHNT News 19 online at WHNT.com as well as on Live Alert 19!

-Jason
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