Alert archive / Tennessee / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 97, NWS Morristown, TN

April 21, 1997Jefferson County, Knox County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Apr 21, 1997, 5:14 PM EDT for Jefferson County, Knox County, Tennessee. It was in force for 31 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: Apr 21, 1997, 5:14 PM EDT (21:14 UTC)
Expired: Apr 21, 1997, 5:45 PM EDT
In force: 31 min
Issued by: NWS Morristown, TN
Area: Whole counties

Counties Jefferson County, TN, Knox County, TN

The radar

The Knoxville radar (KMRX), 31 km from the middle of the area, began a volume at 21:15 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

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

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 9.2 hours before the alert went out and 262 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1346 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: 141 m²/s²
0-3 km storm-relative helicity: 278 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KMRX 212115 RRA
SVRMRX
TNC089-093-212145-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE KNOXVILLE TRI CITIES TN
514 PM EDT MON APR 21 1997
 
THE NATIONAL WEATHER SERVICE IN KNOXVILLE TRI CITIES HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  545 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN EAST TENNESSEE
 
   ...JEFFERSON COUNTY...KNOX COUNTY
 
A SEVERE THUNDERSTORM NORTHEAST OF STRAWBERRY PLAINS WILL MOVE
EAST-NORTHEAST AT 30 MPH TOWARD JEFFERSON CITY AND NEW MARKET...THE
STORM WILL MOVE INTO THOSE AREAS BY 5:30 PM. THIS STORM WILL DROP HEAVY
RAIN ON GROUND THAT IS ALREADY APPROACHING SATURATION...CAUSING FLOODED
ROADWAYS AND RISING CREEKS. THE STORM WILL ALSO PRODUCE DEADLY LIGHTNING
AND POSSIBLE LARGE HAIL.
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A
STRONG BUILDING.  DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...
AND DEADLY LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS.
STAY INSIDE AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED.

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, 2 hours 6 minutes earlier.

Area forecast discussion, Apr 21, 3:08 PM EDT, 2 hours 6 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, 12 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

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 21, 12:18 PM EDT	Severe Thunderstorm Warning	MRX	Blount, Sevier	27 min
Apr 21, 12:55 PM EDT	Severe Thunderstorm Warning	MRX	Cocke, Jefferson, Sevier	50 min
Apr 21, 3:30 PM EDT	Severe Thunderstorm Warning	MRX	Blount, Knox	60 min
Apr 21, 4:21 PM EDT	Severe Thunderstorm Warning	MRX	Anderson, Knox	54 min
Apr 21, 4:44 PM EDT	Severe Thunderstorm Warning	MRX	Jefferson	31 min
Apr 21, 5:08 PM EDT	Flash Flood Warning	MRX	Knox	2 hr
Apr 21, 5:08 PM EDT	Severe Thunderstorm Warning	MRX	Fentress	37 min
Apr 21, 5:27 PM EDT	Severe Thunderstorm Warning	MRX	Morgan	33 min
Apr 21, 5:44 PM EDT	Severe Thunderstorm Warning	MRX	Scott	31 min
Apr 21, 6:04 PM EDT	Severe Thunderstorm Warning	MRX	Campbell	26 min
Apr 21, 6:25 PM EDT	Severe Thunderstorm Warning	MRX	Monroe	35 min
Apr 21, 6:31 PM EDT	Severe Thunderstorm Warning	MRX	Claiborne	29 min
Apr 21, 6:38 PM EDT	Severe Thunderstorm Warning	MRX	Meigs, Rhea	37 min
Apr 21, 7:08 PM EDT	Tornado Warning	MRX	McMinn	37 min
Apr 21, 7:41 PM EDT	Severe Thunderstorm Warning	MRX	Monroe	34 min
Apr 21, 7:46 PM EDT	Severe Thunderstorm Warning	MRX	Bradley, McMinn	29 min
Apr 21, 7:51 PM EDT	Severe Thunderstorm Warning	MRX	Hamilton	39 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.