Alert archive / Tennessee / Special Weather Statements in 2011

Special Weather Statement, NWS Nashville, TN

August 21, 2011Robertson County, Tennessee

NWS Nashville, TN issued this special weather statement at Aug 21, 2011, 3:20 AM CDT for Robertson County, Tennessee. It was in force for 25 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: Aug 21, 2011, 3:20 AM CDT (08:20 UTC)
Expired: Aug 21, 2011, 3:45 AM CDT
In force: 25 min
Issued by: NWS Nashville, TN

County Robertson County, TN

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 8.3 hours before the alert went out and 49 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: 265 J/kg
Mixed-layer CIN: -151 J/kg
Mixed-layer LCL: 2031 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 156 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

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

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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 Aug 20, 11:41 PM CDT, 3 hours 39 minutes earlier.

Area forecast discussion, Aug 20, 11:41 PM CDT, 3 hours 39 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1141 PM CDT SAT AUG 20 2011

.UPDATE...FOR 06Z TAFS.

&&

.AVIATION...
ML/UL TROUGH AND ASSOCIATED COLD FRONT WILL MOVE INTO THE AREA
SUNDAY. THIS FRONT EXPECTED TO BE NEAR BNA 00Z MONDAY...THEN EAST
OF CSV 06Z. GENERATED PCPN AHEAD LIKELY TO MOVE TO BNA VCNTY
BEFORE 12Z...AND OVER TO CSV 14-15Z....HANGING AROUND INTO THE
LATE AFTERNOON. THIS PCPN MAY REDUCE VSBYS BRIEFLY BUT CEILINGS
LIKELY TO STAY AOB 3KFT. OVERALL...VFR CONDITIONS WILL RULE THE
PERIOD...DESPITE PASSING WEAK SYSTEM.

&&

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

07

Hazardous weather outlook, Aug 20, 5:18 AM CDT, 22 hours 2 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
518 AM CDT SAT AUG 20 2011

TNZ005>011-022>034-056>066-075-077>080-093>095-211030-
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-
518 AM CDT SAT AUG 20 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

ROSE

In the hours before

Special weather statement, Aug 21, 3:20 AM CDT, 0 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
320 AM CDT SUN AUG 21 2011

TNZ007-008-026-027-210845-
CHEATHAM-DAVIDSON-ROBERTSON-SUMNER-
320 AM CDT SUN AUG 21 2011

...SIGNIFICANT WEATHER ADVISORY FOR CHEATHAM...DAVIDSON...ROBERTSON
AND SUMNER COUNTIES...

AT 317 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 10 MILES NORTH OF ASHLAND CITY...MOVING EAST AT
30 MPH.

HALF INCH SIZE HAIL...AND WINDS 40 TO 50 MPH ARE EXPECTED WITH THIS
STORM.

LAT...LON 3647 8659 3619 8668 3635 8718 3642 8716
      3642 8715 3645 8715 3646 8712 3646 8713
      3651 8712 3652 8711

ROSE

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 21, 2:25 AM CDT	Severe Thunderstorm Warning	OHX	Cheatham, Montgomery, Robertson	50 min
Aug 21, 4:39 AM CDT	Severe Thunderstorm Warning	OHX	Cheatham, Davidson, Robertson, Sumner	36 min
Aug 21, 5:09 AM CDT	Severe Thunderstorm Warning	OHX	Davidson, Robertson, Rutherford, Sumner, Wilson	21 min

Nearby

Special Weather Statements in Tennessee, 2011 Every special weather statement in 2011

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.