Alert archive / North Carolina / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 91, NWS Morristown, TN

May 20, 2008Cherokee County, Clay County, North Carolina

NWS Morristown, TN issued this severe thunderstorm warning at May 20, 2008, 4:38 PM EDT for Cherokee County, Clay County, North Carolina. It was in force for 67 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
May 20, 2008, 4:38 PM EDT (20:38 UTC)
Expired
May 20, 2008, 5:45 PM EDT
In force
67 min
Issued by
NWS Morristown, TN
Area
Storm-based polygon

Counties Cherokee County, NC, Clay County, NC

The radar

The Knoxville radar (KMRX), 128 km from the middle of the area, began a volume at 20:38 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.

IssuedProductOfficeLasted
May 20, 2:59 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 8.6 hours before the alert went out and 199 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, Peachtre/Fal Fld, GA at 12:00Z on 2008-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 572 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, Peachtre/Fal Fld, GA at 12:00Z on 2008-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 225 square meters per square second.19395878Sfc1 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
572 J/kg
Mixed-layer CIN
-199 J/kg
Mixed-layer LCL
979 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
225 m²/s²
0-3 km storm-relative helicity
251 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.3

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 Morristown, TN wrote its last area forecast discussion before this severe thunderstorm warning went out at May 20, 2:42 PM EDT, 1 hour 56 minutes earlier.

Area forecast discussion, May 20, 2:42 PM EDT, 1 hour 56 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
242 PM EDT TUE MAY 20 2008

.SHORT TERM...(TONIGHT AND WEDNESDAY)...MAIN SHORT-WAVE IS MOVING
ACROSS THE MID-ATLANTIC REGION WITH ANOTHER WEAKER WAVE OVER THE
MID-WEST. ENHANCED CLOUD COVER ALONG THE TENNESSEE-KENTUCKY STATE-
LINE IS ASSOCIATED WITH A JET MAX MOVING SOUTHEAST WITH THE
SECONDARY SHORT-WAVE. MODELS SHOW A DIVERGENCE MAX AT 300MB
ASSOCIATED WITH THE LEFT EXIT REGION OF THE JET. THIS WAVE WILL MOVE
SOUTHEAST ACROSS THE FORECAST AREA DURING THE NEXT COUPLE OF HOURS.

AT THE SURFACE...A COLD FRONT EXTENDS FROM JUST SOUTH OF BNA TO
AROUND LNP. AS WAVE MOVES SOUTHEAST...COLD FRONT WILL MOVE ACROSS
THE FORECAST AREA THE REMAINDER OF THE AFTERNOON-EARLY EVENING.
SATELLITE AND RADAR SHOWS CONVECTIVE DEVELOPMENT OVER THE NORTHERN
HALF OF THE REGION. SCATTERED TO BROKEN THUNDERSTORM DEVELOPMENT
ANTICIPATED. LAPS SHOWS CAPES BETWEEN 1400-1800 J/KG ACROSS THE
VALLEY WITH LIFTED INDICES BETWEEN -2 AND -4. ISOLATED SEVERE
THUNDERSTORMS IS POSSIBLE WITH THE MAIN CONCERN BEING LARGE HAIL UP
TO QUARTER SIZE AND DAMAGING WINDS.

AS FRONT PULLS SOUTH OF THE AREA...CONVECTION WILL SLOWLY DIMINISH
WITH ONLY ISOLATED SHOWERS ANTICIPATED OVER THE NORTHERN AREAS AFTER
MIDNIGHT.

FOR WEDNESDAY...SURFACE RIDGING WILL BUILD INTO THE REGION WITH DRY
CONDITIONS RETURNING.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)...GFS SHOWING A LONG
PERIOD OF NORTHWEST FLOW OVER THE REGION WITH A FEW SHORTWAVES
MOVING THROUGH THE FLOW. THE FIRST SYSTEM WILL BE ON THURSDAY
LINGERING INTO FRIDAY. THE NEXT ONE ON SATURDAY THEN CLEARING OUT
SUNDAY THROUGH TUESDAY. RAINFALL AMOUNTS APPEAR A LITTLE LIMITED
WITH THESE SYSTEMS WTIH GENERALLY A QUARTER TO HALF INCH ALTHOUGH
LOCALIZED AMOUNTS COULD BE HIGHER.

MODEL TEMPERATURES APPEAR REASONABLE WITH A LITTLE BELOW NORMAL AS
CAN BE EXPECTED IN NORTHWEST FLOW.

&&

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN  56  77  52  78  59 /  20  10  10  40  20
KNOXVILLE MCGHEE TYSON AIRPORT, TN  52  74  49  75  55 /  20  10  10  20  20
OAK RIDGE, TN  52  75  49  74  54 /  20  10  10  20  20
TRI CITIES AIRPORT, TN  50  69  43  71  49 /  20  10  10  20  10

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...WIND ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR THE FOLLOWING
     ZONES: CHEROKEE...CLAY.

TN...WIND ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR THE FOLLOWING
     ZONES: BLOUNT SMOKY MOUNTAINS...COCKE SMOKY MOUNTAINS...
     EAST POLK...JOHNSON...SEVIER SMOKY MOUNTAINS...SOUTHEAST
     CARTER...SOUTHEAST GREENE...SOUTHEAST MONROE...UNICOI.

     LAKE WIND ADVISORY UNTIL 4 PM EDT /3 PM CDT/ THIS AFTERNOON FOR
     THE FOLLOWING ZONES: ANDERSON...BLEDSOE...BRADLEY...
     CAMPBELL...CLAIBORNE...GRAINGER...HAMBLEN...HAMILTON...
     HANCOCK...HAWKINS...JEFFERSON...KNOX...LOUDON...MARION...
     MCMINN...MEIGS...MORGAN...NW BLOUNT...NORTH SEVIER...
     NORTHWEST CARTER...NORTHWEST COCKE...NORTHWEST GREENE...
     NORTHWEST MONROE...RHEA...ROANE...SCOTT TN...SEQUATCHIE...
     SULLIVAN...UNION...WASHINGTON TN...WEST POLK.

VA...WIND ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR THE FOLLOWING
     ZONES: WISE.

     LAKE WIND ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR THE
     FOLLOWING ZONES: LEE...RUSSELL...SCOTT...WASHINGTON.

&&

DH/HW
Hazardous weather outlook, May 20, 10:20 AM EDT, 6 hours 18 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MORRISTOWN TN
1020 AM EDT TUE MAY 20 2008

UPDATED FOR RISK OF SEVERE STORMS TODAY.

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-210845-
CHEROKEE-CLAY-SCOTT TN-CAMPBELL-CLAIBORNE-HANCOCK-HAWKINS-
SULLIVAN-JOHNSON-MORGAN-ANDERSON-UNION-GRAINGER-HAMBLEN-
NORTHWEST COCKE-COCKE SMOKY MOUNTAINS-NORTHWEST GREENE-
SOUTHEAST GREENE-WASHINGTON TN-UNICOI-NORTHWEST CARTER-
SOUTHEAST CARTER-ROANE-LOUDON-KNOX-JEFFERSON-NW BLOUNT-
BLOUNT SMOKY MOUNTAINS-NORTH SEVIER-SEVIER SMOKY MOUNTAINS-
SEQUATCHIE-BLEDSOE-RHEA-MEIGS-MCMINN-NORTHWEST MONROE-
SOUTHEAST MONROE-MARION-HAMILTON-BRADLEY-WEST POLK-EAST POLK-LEE-
WISE-SCOTT-RUSSELL-WASHINGTON-
1020 AM EDT TUE MAY 20 2008 /920 AM CDT TUE MAY 20 2008/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST NORTH
CAROLINA...EAST TENNESSEE AND SOUTHWEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

A COLD FRONT WILL MOVE SOUTH ACROSS THE REGION TODAY. AIRMASS WILL
BECOME UNSTABLE IN ADVANCE OF THE FRONT WITH SCATTERED THUNDERSTORMS
ANTICIPATED BY THIS AFTERNOON. SOME OF THESE STORMS MAY BECOME
SEVERE WITH THE MAIN THREAT BEING LARGE HAIL UP TO QUARTER SIZE AND
DAMAGING WINDS.

WINDY CONDITIONS WILL CONTINUE INTO THIS AFTERNOON...WITH SOUTHWEST
WINDS OF 15 TO 35 MPH AND GUSTS FROM 40 TO 50 MPH. THE STRONGEST
WINDS WILL OCCUR ABOVE 2500 FEET...AND THE WINDS SHOULD DIMINISH BY
MID TO LATE AFTERNOON AS AN AREA OF LOW PRESSURE MOVES EAST OF THE
APPALACHIANS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EARLY EVENING.

DH

In the hours before

Local storm report, May 20, 3:46 PM EDT, 52 minutes before
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Local storm report, May 20, 4:01 PM EDT, 37 minutes before
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Local storm report, May 20, 4:02 PM EDT, 36 minutes before
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Local storm report, May 20, 4:16 PM EDT, 22 minutes before
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Special weather statement, May 20, 4:22 PM EDT, 16 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MORRISTOWN TN
422 PM EDT TUE MAY 20 2008

TNZ099-100-202115-
BRADLEY-HAMILTON-
422 PM EDT TUE MAY 20 2008

...A STRONG THUNDERSTORM WILL BE AFFECTING BRADLEY AND HAMILTON
COUNTIES...

AT 417 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR CHATTANOOGA...MOVING EAST AT 35 MPH.

PEA SIZE HAIL...AND WINDS AROUND 40 MPH ARE EXPECTED WITH THIS STORM.

IN ADDITION TO SMALL HAIL AND GUSTY WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THESE STORMS. MOVE INDOORS
IMMEDIATELY LIGHTNING IS ONE OF NATURES PRIMARY KILLERS. REMEMBER...
IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY
LIGHTNING.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM EDT
TUESDAY EVENING FOR SOUTHWEST NORTH CAROLINA AND CENTRAL TENNESSEE.

DH
Local storm report, May 20, 4:37 PM EDT, 1 minute before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
437 PM EDT TUE MAY 20 2008

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

0425 PM     HAIL             6 ENE TELLICO PLAINS    35.40N 84.20W
05/20/2008  E1.00 INCH       MONROE             TN   TRAINED SPOTTER

            QUARTER SIZED HAIL. REPORTED BY TRAINED SPOTTER/HAM RADIO
            OPERATOR.

&&

FERRELL

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 3:05 PM EDTSevere Thunderstorm WarningMRXGreene40 min
May 20, 3:06 PM EDTSevere Thunderstorm WarningMRXBledsoe, Meigs, Rhea54 min
May 20, 3:19 PM EDTSevere Thunderstorm WarningMRXBlount, Loudon, McMinn, Monroe56 min
May 20, 3:20 PM EDTSevere Thunderstorm WarningMRXCarter, Unicoi40 min
May 20, 3:42 PM EDTSevere Thunderstorm WarningMRXGreene23 min
May 20, 3:52 PM EDTSevere Thunderstorm WarningMRXMcMinn, Monroe53 min
May 20, 4:15 PM EDTSevere Thunderstorm WarningMRXBlount, Monroe45 min
May 20, 4:27 PM EDTSevere Thunderstorm WarningMRXBradley, Hamilton63 min
May 20, 4:45 PM EDTSevere Thunderstorm WarningMRXMonroe27 min
May 20, 5:01 PM EDTSevere Thunderstorm WarningMRXBradley, McMinn, Polk59 min
May 20, 5:57 PM EDTSevere Thunderstorm WarningMRXPolk32 min
May 20, 5:38 PM EDTSevere Thunderstorm WarningMRXCherokee, Clay55 min

Nearby

Severe Thunderstorm Warnings in North Carolina, 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; radar from the NEXRAD Level II archive.