Alert archive / Tennessee / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 153, NWS Nashville, TN

July 21, 2008DeKalb County, Tennessee

NWS Nashville, TN issued this severe thunderstorm warning at Jul 21, 2008, 4:52 PM CDT for DeKalb County, Tennessee. It was in force for 23 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 21, 2008, 4:52 PM CDT (21:52 UTC)
Expired
Jul 21, 2008, 5:15 PM CDT
In force
23 min
Issued by
NWS Nashville, TN
Area
Storm-based polygon

County DeKalb County, TN

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 21, 2:44 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 9.9 hours before the alert went out and 71 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 2008-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2596 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 12:00Z on 2008-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2596 J/kg
Mixed-layer CIN
-51 J/kg
Mixed-layer LCL
1158 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
83 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Nashville, TN wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 21, 3:41 PM CDT, 1 hour 11 minutes earlier.

Area forecast discussion, Jul 21, 3:41 PM CDT, 1 hour 11 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
341 PM CDT MON JUL 21 2008

.DISCUSSION...
DEVELOPING UPPER LOW OVER THE GREAT LAKES WILL ALLOW AN UPPER TROUGH
TO AMPLIFY OVER MUCH OF THE EASTERN THIRD OF THE COUNTRY THROUGH
WEDNESDAY. TROUGH AXIS WILL EXTEND SOUTHWARD ACROSS THE MID STATE
WITH A RATHER ACTIVE NW FLOW ALOFT.

ALREADY SEEN WITH THE ACTIVE FLOW IS A COMPLEX OF STORMS WHICH IS
CURRENTLY MOVING SOUTHWARD ACROSS THE NORTHERN PLATEAU. THIS
ACTIVITY WILL PERSIST AND ENOUGH INSTABILITY IS PRESENT SO AS TO
WARRANT A SVR TSTM WATCH WHICH WILL REMAIN IN EFFECT UNTIL 8 PM
THIS EVENING.

FOR TONIGHT...NW FLOW REMAINS IN TACT BUT OTHER THAN THE CURRENT
CONVECTION IN OUR EASTERN COUNTIES...AREAS WEST OF THE PLATEAU
MAY NOT SEE MUCH IN THE WAY OF CONVECTION. NEVERTHELESS...SOME
WEEK PVA MAY MOVE ACROSS THE AREA TOWARD 12Z. THUS...LOW POPS WILL
BE NEED FOR THE OVERNIGHT. POPS WILL NEED TO BE ELEVATED SOME
ACROSS THE PLATEAU PER THE WATCH AS WELL AS THE LATEST RADAR
TRENDS JUST PRIOR TO 4 PM.

ON TUESDAY...ASSOCIATED FRONTAL BOUNDARY BEGINS TO MAKE SOUTHWARD
PROGRESS AND WILL BE MOVING SOUTH OF THE OH RIVER IN THE AFTERNOON.
BY 00Z...SHOULD SEE SCT ACTIVITY ACROSS NORTHERN AREAS AND ISOL
STORMS FOR THE SOUTH. GOOD INSTABILITY TOMORROW AFTERNOON AND WE
COULD SEE A FEW SEVERE STORMS.

THE BEST CHANCE FOR SHOWERS AND STORMS...HOWEVER...WILL BE TUESDAY
NIGHT AS THE FROPA OCCURS AND THE BETTER UPPER DYNAMICS ARE IN
PLACE. WILL AGAIN INCLUDE THE RISK OF SVR WITH LARGE HAIL AND
DAMAGING WINDS BEING POSSIBLE.

AS FOR THE SHORT TERM TEMPS...WILL AGAIN TAKE THE OVER FOR LOWS
TONIGHT VERSUS THE MAV. THE REMAINING PERIODS LOOK OK.

IN THE EXT FCST...WE GET A BRIEF REPRIEVE FROM RAIN CHANCES ON WED
NT AND THU AS DRIER AND SOMEWHAT COOLER AIR MOVES IN. THIS WILL BE
SHORT LIVED AS MOISTURE INCREASES AND THE NW FLOW BECOMES ACTIVE
AGAIN. WILL INCLUDE 20-30 POPS FOR THU NT THROUGH SUN NT. THE HIGHER
30 POPS WILL BE ON SAT NT AND SUN WHEN A FRONTAL BOUNDARY APPEARS TO
EXERT ITS GREATEST IMPACT ON THE MID STATE.

AS THE TROUGH PULLS FURTHER EAST...HEIGHT RISES WILL AGAIN BE ON
ORDER ALTHOUGH THE UPPER HIGH STAYS TO OUR WEST. THAT ALL EQUATES
TO A RETURN TO HIGH TEMPS IN THE LOWER TO MID 90S AND LOWS IN THE
LOWER 70S.

.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE      74  95  71  86 /  20  30  50  40
CLARKSVILLE    71  92  69  86 /  20  30  50  30
CROSSVILLE     68  89  66  79 /  60  30  50  40
COLUMBIA       73  95  71  86 /  20  20  50  40
LAWRENCEBURG   73  96  72  86 /  20  20  50  40
WAVERLY        72  93  70  86 /  20  30  50  30

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

21
Hazardous weather outlook, Jul 21, 3:28 PM CDT, 1 hour 24 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
328 PM CDT MON JUL 21 2008

TNZ005>011-022>034-056>066-075-077>080-093>095-222030-
STEWART-MONTGOMERY-ROBERTSON-SUMNER-MACON-CLAY-PICKETT-BENTON-
HOUSTON-HUMPHREYS-DICKSON-CHEATHAM-DAVIDSON-WILSON-TROUSDALE-
SMITH-JACKSON-PUTNAM-OVERTON-FENTRESS-PERRY-HICKMAN-LEWIS-
WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-CANNON-DEKALB-WHITE-
CUMBERLAND-BEDFORD-COFFEE-WARREN-GRUNDY-VAN BUREN-WAYNE-LAWRENCE-
GILES-
328 PM CDT MON JUL 21 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 8 PM CDT THIS
EVENING FOR AREAS NEAR AND IN THE CUMBERLAND PLATEAU REGION.
STORMS COULD PRODUCE DAMAGING WINDS...DESTRUCTIVE HAIL...AND
DEADLY CLOUD TO GROUND LIGHTNING. THESE STORMS COULD ALSO PRODUCE
RAINFALL AMOUNTS OF 1 TO 2 INCHES. THIS WILL PRODUCE FLOODING OF
LOW LYING AND POOR DRAINAGE AREAS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A COLD FRONT WILL PUSH SOUTHWARD...OUT OF THE OHIO VALLEY...INTO
MIDDLE TENNESSEE...TUESDAY NIGHT AND WEDNESDAY. SCATTERED
THUNDERSTORMS WILL DEVELOP ACROSS THE MID STATE...A FEW OF WHICH
COULD BECOME SEVERE...WITH DAMAGING WINDS AND HAIL. HEAVY
DOWNPOURS...AND MINOR LOCALIZED FLOODING...WILL ALSO BE POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

THIS AFTERNOON THROUGH EARLY EVENING SPOTTER AND EMERGENCY
MANAGER ACTIVATION MAY BE NEEDED.

31

In the hours before

Local storm report, Jul 21, 4:00 PM CDT, 52 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NASHVILLE TN
400 PM CDT MON JUL 21 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0349 PM     TSTM WND DMG     6 ENE CELINA            36.58N 85.40W
07/21/2008                   CLAY               TN   LAW ENFORCEMENT

            REPORT OF TREES BLOWN DOWN IN THE MOSS COMMUNITY

&&

JLM
Local storm report, Jul 21, 4:27 PM CDT, 25 minutes before
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Local storm report, Jul 21, 4:27 PM CDT, 25 minutes before
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Local storm report, Jul 21, 4:39 PM CDT, 13 minutes before
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Special weather statement, Jul 21, 4:41 PM CDT, 11 minutes before
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      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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The office that day

Everything else NWS Nashville, TN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 21, 2:49 PM CDTSevere Thunderstorm WarningOHXFentress, Pickett27 min
Jul 21, 3:00 PM CDTSevere Thunderstorm WarningOHXFentress, Pickett17 min
Jul 21, 3:33 PM CDTSevere Thunderstorm WarningOHXClay, Jackson27 min
Jul 21, 4:04 PM CDTSevere Thunderstorm WarningOHXJackson, Macon, Smith26 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 2008Every severe thunderstorm warning in 2008

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.