Alert archive / Tennessee / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 108, NWS Morristown, TN

April 21, 1997Bradley County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Apr 21, 1997, 8:15 PM EDT for Bradley County, Tennessee. It was in force for 15 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Apr 21, 1997, 8:15 PM EDT (00:15 UTC)
Expired: Apr 21, 1997, 8:30 PM EDT
In force: 15 min
Issued by: NWS Morristown, TN
Area: Whole counties

County Bradley County, TN

What was reported inside it

Time	Report	Where	Remark
Apr 21, 8:20 PM EDT	Hail 1	Cleveland/Charleston, TN

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

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

Issued	Product	Office	Lasted
Apr 21, 3:15 PM EDT	Severe Thunderstorm Watch	SPC	6 hr
Apr 21, 7:30 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 0.3 hours before the alert went out and 191 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 15 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 636 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 93 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 Morristown, TN wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 21, 3:08 PM EDT, 5 hours 7 minutes earlier.

Area forecast discussion, Apr 21, 3:08 PM EDT, 5 hours 7 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KNOXVILLE/TRI-CITIES TN
305 PM EDT MON APR 21 1997

VERY IMPRESSIVE E-W BNDRY STRETCHING FROM JUST SOUTH OF BNA THROUGH
CSV AND INTO THE SMOKIES.  KMRX 88D CONTINUES TO SHOW TRAINING OF
CELLS ACROSS THIS SAME AREA AND WITH MORE CONVECTION FIRING UP TO THE
WEST I AM A LTL CONCERNED WITH FLASH FLOODING ACROSS THE PLATEAU AND
CNTRL VLY.  THE WARM FNT CURRENTLY MOVING THROUGH SE TN WL ONLY ADD TO
THE ALREADY IMPRESSIVE MOISTURE CONVERGENCE AND AVAILABLE MOISTURE AND
INSTABILITY.  ADAP IS CURRENTLY SHOWING SURFACE BASED LIS BETWEEN -4
AND -6 SOUTH OF THE WARM FNT.  SO I WOULD LIKE TO MENTION SVR STORMS
FOR AREAS TO THE SOUTH OF THIS E-W BNDRY MAINLY SE TN...SW NC...CNTRL
VLY AND THE PLATEAU.  AS STATED EARLIER LARGE HAIL WL BE THE PRIMARY
THREAT.

BLV THE ACTIVITY WL TEND TO DIMINISH SOMEWHAT AFT MIDNIGHT.  ALTHOUGH
I WOULD NOT TOTALLY TAKE OUT THE POPS COMPLETELY AS A WK VORT MAX WL
TRACK QUICKLY THROUGH KY LATER ON TNT.

THE MODELS SEEM TO BE NOW MORE IN AGREEMENT BEYOND 24 HOURS THAN THEY
HAVE BEEN OVER THE PAST COUPLE OF RUNS.  THE FLOW IS EXPECTED TO
BECOME INCREASINGLY AMPLIFIED AS THE MEAN TROUGH POSN ACROSS THE NRN
PLAINS FINALLY DIGS SEWD INTO THE SRN PLAINS ON TUE.  RAPID
INTENSIFICATION OF A SFC CYCLONE ACROSS THE DEEP SOUTH WL TAKE PLACE
TUE NIGHT INTO WED.  WE COULD BE DEALING WITH MORE SVR WX/HVY RAIN
WITH THIS EPISODE TUE NIGHT INTO WED.  ALTHOUGH I FEEL MCS ACTIVITY
ACROSS MS/AL/GA WL LKLY LIMIT THE OVERALL THREAT AS IS USUAL THE CASE.
LKLY/CAT POPS WL BE NEEDED.

STEPPING BACK TO TUE FOR A MINUTE.  I THINK WE MAY ACTUALLY DRY OUT
AS THE FNT SHIFTS TO A POSN JUST SOUTH OF SE TN AND SW NC.  SO WOULD
US:E CHC/LKLY POPS FOR THIS RGN WHILE CHC POPS SHOULD SUFFICE FOR THE
REMAINDER OF THE CWA.

GUIDANCE TEMPS GNLY ACCEPTED.

MB

In the hours before

Local storm report, Apr 21, 5:02 PM EDT, 3 hours 13 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE KNOXVILLE/TRI-CITIES TN
5O2 PM EDT MON APR 21 1997

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

426  PM    NEAR CLINTON              TN   0.75 INCH HAIL
04/21/97   ANDERSON                       DIME SIZE HAIL LASTED ABOUT
                                          10 MINUTUES

450 PM     NORTH KNOX COUNTY         TN   0.88 INCH HAIL
04/21/97   KNOX                           DIME TO NICKEL SIZE HAIL IN
                                          NORTH AND NORTHEAST KNOX
                                          COUNTY

Local storm report, Apr 21, 6:12 PM EDT, 2 hours 3 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE KNOXVILLE/TRI-CITIES TN
610 PM EDT MON APR 21 1997

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

535 PM     NEAR BURRVILLE            TN   0.75 INCH HAIL
04/21/97   MORGAN                         NICKEL SIZE HAIL NEAR
                                          BURRVILLE IN THE NORTHWEST
                                          PART OF THE COUNTY

515 PM                               TN   1.25 INCH HAIL
04/21/97   FENTRESS                       NICKEL TO HALF DOLLAR SIZE
                                          HAIL IN MARTHA WASHINGTON
                                          COMMUNITY REPORTED BY WDEV
                                          IN JAMESTOWN..LOTS OF
                                          QUARTER SIZE HAIL COVERING
                                          THE GROUND AT 1720 IN
                                          SOUTHERN FENTRESS COUNTY.

530 PM     COUNTY WIDE               TN   FLOODING
04/21/97   KNOX                           WATER COVERING ROADWAYS
                                          COUNTY WIDE INCLUDING PARTS
                                          OF I-40 IN KNOXVILLE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 21, 8:09 PM EDT	Severe Thunderstorm Warning	MRX	Polk	51 min
Apr 21, 8:48 PM EDT	Severe Thunderstorm Warning	MRX	Cherokee	27 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 1997 Every severe thunderstorm warning in 1997

Sources

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