Alert archive / Tennessee / Special Weather Statements in 2012

Special Weather Statement, NWS Nashville, TN

May 20, 2012Smith County, Tennessee

NWS Nashville, TN issued this special weather statement at May 20, 2012, 1:55 PM CDT for Smith County, Tennessee. It was in force for 65 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 20, 2012, 1:55 PM CDT (18:55 UTC)
Expired
May 20, 2012, 3:00 PM CDT
In force
65 min
Issued by
NWS Nashville, TN

County Smith County, TN

The radar

The Nashville radar (KOHX), 69 km from the middle of the area, began a volume at 18:59 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 nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 6.9 hours before the alert went out and 73 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, Nashville Metro, TN at 12:00Z on 2012-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 859 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, Nashville Metro, TN at 12:00Z on 2012-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -16 square meters per square second.1939Sfc1 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
859 J/kg
Mixed-layer CIN
-87 J/kg
Mixed-layer LCL
1235 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-16 m²/s²
0-3 km storm-relative helicity
33 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.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at May 20, 12:16 PM CDT, 1 hour 39 minutes earlier.

Area forecast discussion, May 20, 12:16 PM CDT, 1 hour 39 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1216 PM CDT SUN MAY 20 2012

.AVIATION 18Z DISCUSSION...
UPPER TROUGH AXIS REMAIN IN PLACE ACROSS EASTERN MIDDLE TN.
THUS...TSTM DEVELOPMENT THIS AFT WILL BE MOST NUMEROUS ACROSS THE
PLATEAU OR...CSV VCNTY. THE CONVECTION SHOULD WEAKEN EARLY THIS
EVENING. HOWEVER...AN EASTWARD MOVING SHORTWAVE WILL APPROACH
TOWARD SUNRISE ON MONDAY. THIS WILL BERING RETURNING CHANCES OF
SHOWERS AND TSTMS AS WE MOVE TOWARD 12Z LATE TONIGHT.

TOVER VALUES ARE SLIGHTLY NEGATIVE OR CLOSE TO ZERO THIS
AFTERNOON. WILL THEREFORE INCLUDE VSBYS OF AS LOW AS 3-5SM AT
TIMES...MAINLY LATE TONIGHT.

&&

.PREV DISCUSSION... /ISSUED 1002 AM CDT SUN MAY 20 2012/

UPDATE...MORNING SOUNDING IS VIRTUALLY THE SAME AS YESTERDAY...
BUT WITH SLIGHTLY MORE COLUMN MOISTURE. LOCAL WRF MODEL AGAIN
SHOWS CONVECTION KICKING OFF IN THE PLATEAU COUNTIES AND SPREADING
WWD IN TIME. STORM MOVEMENT STARTS OUT AS SSW AND TURNS TO SOUTH.
AND LIKE YESTERDAY...CONVECTION SHOULD DIE OUT SHORTLY AFTER SUNDOWN.
LACK OF ANY 0-3 KM SHEAR BUT GOOD THERMAL INSTABILITY WILL MEAN
SLOW MOVING STORMS THAT PULSE TO NEAR SEVERE AND THEN DIE OUT.
THUS...WE MAY HAVE A FEW AFTERNOON STORMS THAT EXHIBIT MARBLE
SIZE HAIL AND STRONG GUSTY WINDS.

WRF ALSO SHOWS THE COLD FRONT MOVING INTO THE AREA LATE
TONIGHT/EARLY TOMORROW. AT 7 AM TOMORROW...THE LOCAL WRF SHOWS THE
FRONT ALONG A LINE FROM LOUISVILLE KY TO CLARKSVILLE TN TO PINE
BLUFF AR. CURRENT FORECAST SEEMS ON TRACK...NO CHANGES ATTM.

JLM

PREV DISCUSSION... /ISSUED 629 AM CDT SUN MAY 20 2012/

UPDATE...FOR AVIATION.

AVIATION...
12Z TAFS...PATCHY MVFR BR WILL LIFT BY 14Z. TODAY WILL BE SIMILAR
TO YESTERDAY WITH SCT CU BLOSSOMING TO ISOLD TSRA BETWEEN 18Z-21Z.
COVERAGE WILL BE 10-20 PERCENT...SLOW MOVING STORMS WITH LOCALIZED
HAIL AND GUSTY WINDS. TSRA WILL DISSIPATE WITH SUNSET AROUND 01Z.
AN APPROACHING FRONT COULD BRING NEW SCT TSRA TOWARD 21/12Z FOR
KCKV AND KBNA. WINDS WILL BE LIGHT THROUGH THE TAF PERIOD.

13

PREV DISCUSSION... /ISSUED 339 AM CDT SUN MAY 20 2012/

DISCUSSION...

SIMILAR CONDITIONS TO YDAY EXPECTED TODAY WITH WELL ABOVE NORMAL
TEMPERATURES AND SCATTERED/WIDELY SCATTERED TSTMS DURING THE
AFTERNOON. DOES NOT LOOK QUITE AS UNSTABLE AS YDAY BUT STILL COULD
HAVE A STORM OR TWO PULSE SEVERE. BEST TSTM COVERAGE EXPECTED OVER
THE PLATEAU.

FRONTAL BNDRY WILL APPROACH TNGT THEN SWING THROUGH THE MID STATE
MONDAY AND MONDAY NIGHT. LOOKS LIKE A DECENT CHANCE OF RAIN WITH
THIS SYSTEM AND GIVEN FORECAST MOISTURE PROFILES AND A DECENT
DIURNAL TIMING OF THE FRONT HAVE UPPED POPS TO LIKELY FOR MOST OF
THE MID-STATE ON MONDAY. UNDERCUT MAV TEMPS A LITTLE ON MONDAY
WITH A FAIR AMNT OF CLOUDS EXPECTED.

A COUPLE PRETTY NICE DAYS LOOK TO BE IN STORE FOR TUESDAY AND
WEDNESDAY WITH HIGHS CLOSER TO NORMAL AND LOW HUMIDITY. AFTER
WEDNESDAY HOWEVER IT LOOKS LIKE MID-SUMMER HEAT IN MAY AS VERY
STRONG RIDGING ALOFT IS FORECAST BY ALL MEDIUM RANGE MODELS. OTHER
THAN ISOLATED DIURNAL CONVECTION RAIN CHANCES LOOK VERY SLIM IN
THE EXTENDED PART OF THE FCST.

TOMSTONE

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

21
Hazardous weather outlook, May 20, 5:06 AM CDT, 8 hours 49 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
506 AM CDT SUN MAY 20 2012

TNZ005>011-022>034-056>066-075-077>080-093>095-211015-
STEWART-MONTGOMERY-ROBERTSON-SUMNER-MACON-CLAY-PICKETT-BENTON-
HOUSTON-HUMPHREYS-DICKSON-CHEATHAM-DAVIDSON-WILSON-TROUSDALE-
SMITH-JACKSON-PUTNAM-OVERTON-FENTRESS-PERRY-HICKMAN-LEWIS-
WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-CANNON-DE KALB-WHITE-
CUMBERLAND-BEDFORD-COFFEE-WARREN-GRUNDY-VAN BUREN-WAYNE-LAWRENCE-
GILES-
506 AM CDT SUN MAY 20 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT

A FEW THUNDERSTORMS ARE EXPECTED TO DEVELOP AGAIN THIS AFTERNOON
ACROSS MIDDLE TENNESSEE. SOME OF THE STORMS WILL BE STRONG TO
LOCALLY SEVERE AND CAPABLE OF PRODUCING HAIL AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY...

SHOWERS AND THUNDERSTORMS ARE EXPECTED AHEAD OF A COLD FRONT ON
MONDAY AND A FEW STORMS COULD BE SEVERE DURING THE AFTERNOON. HAIL
AND STRONG WINDS ARE THE MAIN THUNDERSTORM THREATS.

.SPOTTER CALL TO ACTION STATEMENT...

EVEN THOUGH ANY SEVERE THUNDERSTORMS ARE EXPECTED TO BE BRIEF AND
ISOLATED, SPOTTERS ARE ENCOURAGED TO CLOSELY MONITOR WEATHER
CONDITIONS AND BE PREPARED TO CALL IN ANYTHING REACHING REPORTING
CRITERIA.

SPOTTER THUNDERSTORM REPORTING CRITERIA...
TORNADO
FUNNEL CLOUD
FLOODING
HAIL >= 1/2 INCH
WINDS > 50 MPH (MEASURED)
STRUCTURAL DAMAGE
TREES OR POWER LINES DOWN

06

In the hours before

Special weather statement, May 20, 1:55 PM CDT, 0 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
155 PM CDT SUN MAY 20 2012

TNZ030-031-202000-
JACKSON-SMITH-
155 PM CDT SUN MAY 20 2012

...SIGNIFICANT WEATHER ADVISORY FOR JACKSON AND SMITH COUNTIES...

AT 153 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 6 MILES WEST OF GAINESBORO...MOVING SOUTHWEST AT
10 MPH.

HALF INCH SIZE HAIL IS EXPECTED WITH THIS STORM.

LAT...LON 3635 8571 3623 8574 3624 8578 3621 8578
      3621 8581 3619 8579 3618 8581 3617 8579
      3616 8581 3624 8599 3640 8585

21

The office that day

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

IssuedProductOfficeCountiesLasted
May 19, 7:18 PM CDTSpecial Weather StatementOHXGiles, Lewis, Maury42 min
May 20, 2:06 PM CDTSevere Thunderstorm WarningOHXJackson, Putnam, Smith39 min
May 20, 2:12 PM CDTSpecial Weather StatementOHXVan Buren48 min
May 20, 2:32 PM CDTSevere Thunderstorm WarningOHXSmith21 min
May 20, 4:06 PM CDTSpecial Weather StatementOHXTrousdale39 min
May 20, 4:30 PM CDTSpecial Weather StatementOHXCoffee, Grundy60 min

Nearby

Special Weather Statements in Tennessee, 2012Every special weather statement in 2012

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.