Alert archive / Tennessee / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 211, NWS Morristown, TN

May 21, 1998Knox County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at May 21, 1998, 6:45 PM EDT for Knox County, Tennessee. It was in force for 30 min. 5 reports 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: May 21, 1998, 6:45 PM EDT (22:45 UTC)
Expired: May 21, 1998, 7:15 PM EDT
In force: 30 min
Issued by: NWS Morristown, TN
Area: Whole counties

County Knox County, TN

What was reported inside it

Time	Report	Where
May 21, 6:50 PM EDT	Hail 1	Knoxville, TN
May 21, 7:05 PM EDT	Hail 2	Knoxville, TN
May 21, 7:08 PM EDT	Hail 1.75	Knoxville, TN
May 21, 7:16 PM EDT	Hail 2	Knoxville, TN
May 21, 7:18 PM EDT	Hail 0.75	Knoxville, 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
May 21, 6:15 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 10.8 hours before the alert went out and 240 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: 1382 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 1095 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 139 m²/s²
0-3 km storm-relative helicity: 162 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.5

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 May 21, 2:35 PM EDT, 4 hours 10 minutes earlier.

Area forecast discussion, May 21, 2:35 PM EDT, 4 hours 10 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KNOXVILLE/TRI-CITIES TN
235 PM EDT THU MAY 21 1998

...MAIN FCST CHLG IS PRECIP CHCS THRU FCST PRD...

CRNT SFC ANALYSIS SHOS CLD FRNT NR KY/TN BRDR ATTM. LTL CONV HAS FIRED
ALNG FRNT DUE TO WEAK CAP OVR AREA. CRNT IR PIC SHOS 3 DIST MCSS OVR
MO..AND NE ATTM. THCKNS PATTERNS INDIC THAT MCSS SHUD CONT A SE
MOVMNT.  CRNT ADAP PRODS SHO LIS -10 TO -15 AND 0 CAP ATTM. SO AS UPR
LVL S/W MOVS INTO THE AREA W/ A LTL MORE SFC WARMING SHUD SEE SCT TSRA
OVR THE AREA THRU THIS EVENING.

TONITE...W/ MCSS MOVING TWRDS SW VA/AND NE TN WOULD LIKE TO SEE A
GOOD CHC OF TSRA OVERNIGHT (50%) FOR THE REMAINDER OF THE AREA WOULD
LIKE TO SEE A CHC OF TSRA (30%). AS FAR AS TEMPS GO...FWC/FAN NUMBERS
LOOK GOOD.  (60 TO 65) WK THETA-E RIDGE BUILDS INTO THE NE PORTION OF
THE CWA WHICH WOULD INDICATE CRNT MCS SHUD REMAIN OVER THAT AREA.

FRIDAY...THCKNS PATTERNS TURN MOR SE OVR CWA AND UPR LVL S/WS MOV
INTO THE AREA UNDER WK NW FLOW...SO MCSS OVR NORTHERN MO AND NEBRASKA
SHUD MOV INTO THE AREA. UPR LVL DYNAMICS LUK WK ATTM HOWEVER THETA-E
RIDGE BUILDS OVR THE AREA SO PRECIP CHCS SHUD BE PRESENT...SO WOULD
LIKE TO INTRODUCE A 40 PERCENT CHC OF TSRA DURING THE DAY.  FWC/FAN
TEMPS LUK GOOD.  PARTLY CLOUDY SHUD PREVAIL ACRS CWA.  (80 TO 85)

FRIDAY NITE...ENTIRE CWA STAYS UNDER WK NW FLOW AND WK S/WS CONT TO
MOV THRU THE AREA SO WOULD LIKE TO GO PARTLY CLOUDY W/ A 30 PERCENT
CHC OF SHRA AND TSRA.  FWC/FAN TEMPS LUK GOOD. (60 TO 65)

SAT...UPR LVL RIDGE BEGINS TO MOV INTO THE AREA AND SHUD PUSH PRECIP
CHCS OFF TO THE EAST OF THE CWA. SO WOULD LIKE TO GO PARTLY CLOUDY
WITH HIGHS 80 TO 85.

PDK

In the hours before

Special weather statement, May 21, 12:47 PM EDT, 5 hours 58 minutes before

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Special weather statement, May 21, 12:51 PM EDT, 5 hours 54 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 9:32 PM EDT	Severe Thunderstorm Warning	MRX	Carter, Johnson	33 min
May 20, 10:14 PM EDT	Severe Thunderstorm Warning	MRX	Johnson, Sullivan	46 min
May 21, 4:55 PM EDT	Severe Thunderstorm Warning	MRX	Roane	35 min
May 21, 5:45 PM EDT	Severe Thunderstorm Warning	MRX	Loudon	35 min
May 21, 5:55 PM EDT	Severe Thunderstorm Warning	MRX	Knox	50 min
May 21, 6:32 PM EDT	Severe Thunderstorm Warning	MRX	Roane	33 min
May 21, 6:48 PM EDT	Severe Thunderstorm Warning	MRX	Jefferson, Sevier	47 min
May 21, 6:52 PM EDT	Flash Flood Warning	MRX	Knox	2 hr
May 21, 7:14 PM EDT	Severe Thunderstorm Warning	MRX	Knox	31 min
May 21, 7:29 PM EDT	Severe Thunderstorm Warning	MRX	Roane	31 min
May 21, 7:39 PM EDT	Severe Thunderstorm Warning	MRX	Cocke	36 min
May 20, 8:02 PM EDT	Severe Thunderstorm Warning	MRX	Wise	48 min
May 20, 8:04 PM EDT	Severe Thunderstorm Warning	MRX	Washington	51 min
May 20, 8:54 PM EDT	Severe Thunderstorm Warning	MRX	Washington	46 min
May 20, 9:03 PM EDT	Flash Flood Warning	MRX	Washington	3 hr

Nearby

Severe Thunderstorm Warnings in Tennessee, 1998 Every severe thunderstorm warning in 1998

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.