Alert archive / Tennessee / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 345, NWS Nashville, TN

June 21, 1998Sumner County, Tennessee

NWS Nashville, TN issued this severe thunderstorm warning at Jun 21, 1998, 6:30 AM CDT for Sumner County, Tennessee. It was in force for 55 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: Jun 21, 1998, 6:30 AM CDT (11:30 UTC)
Expired: Jun 21, 1998, 7:25 AM CDT
In force: 55 min
Issued by: NWS Nashville, TN
Area: Whole counties

County Sumner County, TN

The radar

The Nashville radar (KOHX), 26 km from the middle of the area, began a volume at 11:33 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.

What was reported inside it

Time	Report	Where	Remark
Jun 21, 6:45 AM CDT	Thunderstorm Wind 50	West Central Portion, TN	Off duty NWS employee reported large tree limbs down in White House.

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 nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 11.5 hours before the alert went out and 40 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: 1573 J/kg
Mixed-layer CIN: -56 J/kg
Mixed-layer LCL: 1215 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 230 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

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

592 
WUUS1 KBNA 211136
SVRBNA
TNC165-211220-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED
NATIONAL WEATHER SERVICE NASHVILLE TN
630 AM CDT SUN JUN 21 1998

THE NATIONAL WEATHER SERVICE IN NASHVILLE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SUMNER COUNTY IN MIDDLE TENNESSEE

* UNTIL 725 AM CDT

* AT 626 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM NEAR PORTLAND... MOVING EAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  OAK GROVE BY 635 AM CDT
  COTTONTOWN BY 635 AM CDT
  WESTMORELAND BY 645 AM CDT
  BETHPAGE BY 645 AM CDT

DAMAGING WINDS AND HEAVY RAIN ARE LIKELY. GO INSIDE A STURDY
BUILDING AND STAY AWAY FROM WINDOWS

WSS

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 Jun 21, 3:15 AM CDT, 3 hours 15 minutes earlier.

Area forecast discussion, Jun 21, 3:15 AM CDT, 3 hours 15 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
315 AM CDT SUN JUN 21 1998

S/W CROSSG LWR OH VLY ATTM HELPG TO FIRE WDLY SCT/SCT CONVCTN OVR CNTRL
KY AND NE MID TN. MEANWHILE SLOWLY DECAYING MCS OVR SRN IL MOVING ALONG
850 THETA-E GRADIENT. THIS GRADIENT EXTDS INTO NRN MID TN WHERE IT
RELAXES A BIT. THUS XPCT SRN IL CONVCTN TO MOV INTO NRN MID TN
ARD/SHORTLY AFT DAYBREAK. WHILE THIS ACTIVITY MAY DSIPT BY MID/LATE AM
...PRESENCE OF OUTFLOW BNDRY FM THIS AND PREVIOUS CNVCTN SAT NIGHT WL
PROVIDE FOCUS FOR CNVTV DVLPMNT LATR TDY/EARLY TNGT. AS WAS WITNESSED
SAT...DRIER AIR PROGGED BY MDL SNDGS TO PERSISTS IN MID LAYERS OF
ATMOS. THUS XPCT DAMAGING DOWNBURSTS WITH STRGR/SVR STORMS TDY. PRECIP
WATER VALUES ARD 1.5-1.6 INCHES AND PROGGED TO CHG LTL THRU FCST PD.
WITH MDT UNSTBL/MOIST AMS IN PLACE AND WK DIFLUENCE PROGGED TO CONT
THRU 48 HRS...XPCT SCT TO NMRS SHWRS/TSTMS TDY/MON.

BY MON...MDLS DEPICT RISING HGTS OVR RGN WHILE SFC FNT DRAPED ACRS LWR
OH VLY. MOST ACTIVE WEATHER ANTICIPATED ALONG/N OF THIS FRNT BUT WITH
HIGH THETA-E AIR IN PLACE OVR TN VLY AND WK DIFLUENT FLOW PROGGED TO
CONT...WL LIKELY SEE CONCTN OVR LWR OH VLY WORKS ITS WAY INTO TN
VLY..ESP DURG THE HEAT OF THE DAY. DUE TO ABV SCENARIO...MOS POPS APPR
TOO LOW FOR MON. FLASH FLOODING WL BE A PROBLEM WITH SLOW MOVING
STORMS...HWVR DIFFICULT TO PINPOINT MOST FAVORED AREA FOR FF THREAT.
PROBABLY BEST TO HGIHLIGHT HVY RAIN IN TEXT OF ZNS RATHER THAN ISSUE
FFA. MAY ALSO WANT TO MENTION POSSIBILITY OF SVR SINCE SPC HAS MUCH OF
RGN OUTLOOKED IN SLGT RISK TDY.

TEMPS TRICKY AND DEPENDENT UPON CLD DEBRIS/INITIATION OF CNVCTN. ATTM
FAVOR TEMPS A COUPLE OF DEGS COOLER THAN FWC GUID.
09

BNA 90/70/92 635                          COOKEVILLE 88/67/90 636
                LAWRENCEBURG 92/69/93 623

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 20, 7:14 PM CDT	Tornado Warning	OHX	Rutherford	51 min
Jun 20, 7:34 PM CDT	Severe Thunderstorm Warning	OHX	Wilson	31 min
Jun 21, 2:13 AM CDT	Flash Flood Warning	OHX	Clay, Overton, Pickett	2 hr
Jun 21, 2:13 AM CDT	Flash Flood Warning	OHX	Jackson, Macon	2 hr
Jun 21, 7:30 AM CDT	Flash Flood Warning	OHX	Clay, Overton, Pickett	3 hr
Jun 21, 7:30 AM CDT	Flash Flood Warning	OHX	Jackson, Macon, Sumner	3 hr
Jun 21, 8:39 AM CDT	Flash Flood Warning	OHX	Putnam, Smith, Trousdale, Wilson	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; radar from the NEXRAD Level II archive.