Alert archive / Tennessee / Mesoscale Discussions in 2003

Mesoscale Discussion 587

April 25, 200319 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2003, 6:48 PM CDT for 19 counties in Tennessee. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Apr 25, 2003, 6:48 PM CDT (23:48 UTC)
Expired: Apr 25, 2003, 8:15 PM CDT
In force: 87 min
Issued by: the Storm Prediction Center

Counties Bledsoe County, TN, Bradley County, TN, Clay County, TN, Cumberland County, TN, DeKalb County, TN, Fentress County, TN, Grundy County, TN, Hamilton County, TN, Jackson County, TN, Marion County, TN, Meigs County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Rhea County, TN, Sequatchie County, TN, Van Buren County, TN, Warren County, TN, White County, TN

The radar

The Nashville radar (KOHX), 111 km from the middle of the area, began a volume at 23:51 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, 11.8 hours before the alert went out and 112 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: 3 J/kg
Mixed-layer CIN: -232 J/kg
Mixed-layer LCL: 656 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 279 m²/s²
0-3 km storm-relative helicity: 296 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.

956 
ACUS11 KWNS 252348
SWOMCD
SPC MCD 252348 
TNZ000-KYZ000-GAZ000-ALZ000-260115-

MESOSCALE DISCUSSION 0587
NWS STORM PREDICTION CENTER NORMAN OK
0648 PM CDT FRI APR 25 2003

AREAS AFFECTED...MIDDLE AND ERN TN...

CONCERNING...SEVERE THUNDERSTORM WATCH 170...

VALID 252348Z - 260115Z

SEVERE THREAT -- PRIMARILY IN THE FORM OF HAIL UP TO 1.25 -- IS
FORECAST TO CONTINUE ACROSS THE CUMBERLAND PLATEAU AND EVENTUALLY
INTO ERN TN OVER THE NEXT 1 TO 2 HOURS.

LATEST SURFACE ANALYSIS SHOWS COLD FRONT MOVING EWD ACROSS MIDDLE
TN...ALONG WITH A BROKEN LINE OF SEVERE STORMS -- OCCASIONALLY
SHOWING SOME ROTATION.	INSTABILITY REMAINS MARGINAL /AROUND 500
J/KG MEAN-LAYER CAPE/...BUT LARGE-SCALE FORCING ASSOCIATED WITH VORT
MAX NOW IN FAR WRN KY SHOULD SUPPORT A CONTINUATION OF THE
CONVECTION ACROSS THE AREA.  ALTHOUGH MODERATELY STRONG / WEAKLY
VEERING DEEP-LAYER WIND FIELD IS INDICATED BY MORRISTOWN TN
WSR-88D...LIMITED INSTABILITY SUGGESTS THAT HAIL OR PERHAPS A
LOCALLY STRONG WIND GUST WILL REMAIN THE PRIMARY SEVERE THREAT.

ATTM...NEW WW IS NOT ANTICIPATED EAST OF CURRENT WATCH AS SLOWLY
DECREASING INSTABILITY SUGGESTS THAT MOST OF THE SEVERE THREAT WILL
HAVE ENDED BY THE 26/02Z EXPIRATION TIME OF WW 170.  

..GOSS.. 04/25/2003

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MRX...JKL...FFC...OHX...HUN...

36598581 36628492 36128472 34938485 34998611

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 24, 11:45 PM CDT	Tornado Watch	SPC	Chester, Crockett, Dyer, Fayette, Gibson, Hardeman and 6 more	5 hr
Apr 25, 1:15 AM CDT	Mesoscale Discussion	SPC	Chester, Crockett, Dyer, Fayette, Gibson, Hardeman and 6 more	90 min
Apr 25, 3:05 AM CDT	Mesoscale Discussion	SPC	Chester, Crockett, Fayette, Hardeman, Hardin, Haywood and 5 more	85 min
Apr 25, 11:04 AM CDT	Mesoscale Discussion	SPC	Benton, Carroll, Chester, Decatur, Dickson, Hardin and 12 more	116 min
Apr 25, 11:50 AM CDT	Severe Thunderstorm Watch	SPC	Bedford, Benton, Bledsoe, Bradley, Cannon, Cheatham and 43 more	5 hr
Apr 25, 1:55 PM CDT	Mesoscale Discussion	SPC	Cheatham, Davidson, Dickson, Hickman, Houston, Lewis and 4 more	2 hr
Apr 25, 3:22 PM CDT	Mesoscale Discussion	SPC	Bedford, Cannon, Cheatham, Davidson, DeKalb, Dickson and 20 more	113 min
Apr 25, 4:40 PM CDT	Tornado Watch	SPC	Clay, Macon	4 hr
Apr 25, 4:45 PM CDT	Severe Thunderstorm Watch	SPC	Bedford, Bledsoe, Bradley, Cannon, Clay, Coffee and 28 more	4 hr

Nearby

Mesoscale Discussions in Tennessee, 2003 Every mesoscale discussion in 2003

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.