Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 571

May 9, 20164 parishes in Louisiana; 31 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 9, 2016, 5:13 PM CDT for 4 parishes in Louisiana; 31 counties in Texas. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: May 9, 2016, 5:13 PM CDT (22:13 UTC)
Expired: May 9, 2016, 6:45 PM CDT
In force: 92 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 35 counties

Bossier Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Webster Parish, LA, Anderson County, TX, Angelina County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Ellis County, TX, Falls County, TX, Freestone County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Houston County, TX, Kaufman County, TX, Leon County, TX, Limestone County, TX, Marion County, TX, McLennan County, TX, Morris County, TX, Nacogdoches County, TX, Navarro County, TX, Panola County, TX, Rains County, TX, Robertson County, TX, Rusk County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Trinity County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 135 km from the middle of the area, began a volume at 22:13 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 157May 9, 7:20 PM CDT

The nearest sounding before it

Shreveport, LA (KBAD), launched 12:00Z, 10.2 hours before the alert went out and 144 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: 15 J/kg
Mixed-layer CIN: -201 J/kg
Mixed-layer LCL: 703 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 173 m²/s²
0-3 km storm-relative helicity: 222 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

364 
ACUS11 KWNS 092213
SWOMCD
SPC MCD 092213 
LAZ000-ARZ000-TXZ000-092345-

MESOSCALE DISCUSSION 0571
NWS STORM PREDICTION CENTER NORMAN OK
0513 PM CDT MON MAY 09 2016

AREAS AFFECTED...PARTS OF NORTH-CENTRAL/CENTRAL TX TO WESTERN
LA/SOUTHWEST AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 092213Z - 092345Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...AT LEAST AN ISOLATED SEVERE THUNDERSTORM RISK MAY
DEVELOP/INCREASE THROUGH LATE AFTERNOON/EARLY EVENING ACROSS PARTS
OF NORTH-CENTRAL/CENTRAL TX...AND POSSIBLY FAR EAST/NORTHEAST TX AND
NEIGHBORING NORTHWEST LA/SOUTHWEST AR. WILL CONTINUE TO MONITOR
DEVELOPMENTAL TRENDS. MORE IMMINENT SIGNS OF DEEP CONVECTIVE
INITIATION COULD PROMPT A WATCH ISSUANCE.

DISCUSSION...A GENERAL INCREASE IN TOWERING CU HAS BEEN NOTED IN
VICINITY OF THE NNE/SSW-EXTENDING DRYLINE ACROSS NORTH-CENTRAL INTO
CENTRAL PARTS OF CENTRAL TX...WITH THE MOST DISCERNIBLE ATTEMPTS AT
CONVECTIVE INITIATION OCCURRING ON THE SOUTHERN/EASTERN FRINGES OF
THE DALLAS-FORT WORTH METROPLEX AS OF 2145Z/445PM CDT. AN EARLIER
/18Z/ OBSERVED SOUNDING FROM FORT WORTH FEATURED SOME CAPPING
BETWEEN 750-850 MB...WHILE NEAR-DRYLINE CONVERGENCE REMAINS MODEST
PER LATEST SURFACE OBSERVATIONS AND REGIONAL WSR-88D VWP DATA /WEAK
CONVERGENCE THROUGH 2-3 KM AGL/. THIS CASTS UNCERTAINTY ABOUT THE
LIKELIHOOD/EXTENSIVENESS OF DEEP CONVECTIVE DEVELOPMENT...BUT AT THE
VERY LEAST...A CONDITIONAL LARGE HAIL THREAT WILL EXIST IF/WHERE
STORMS DEVELOP THROUGH EARLY EVENING. 

FARTHER EAST...ON THE WESTERN FRINGES OF AN
ABATING/EASTWARD-SHIFTING CLOUD SHIELD...A SOMEWHAT SEPARATE
CORRIDOR OF GRADUALLY INCREASING/INTENSIFYING THUNDERSTORMS COULD
DEVELOP ACROSS FAR EAST/NORTHEAST TX INTO NORTHWEST LA/SOUTHERN AR
THROUGH EARLY EVENING AMID MOIST/CONFLUENT LOW-LEVEL FLOW.
DEEP-LAYER/LOW-LEVEL SHEAR WOULD BE SUPPORTIVE OF A TORNADO RISK
ASIDE FROM SEVERE HAIL/LOCALLY DAMAGING WINDS SHOULD STORMS
INCREASE/INTENSIFY.

..GUYER/CORFIDI.. 05/09/2016

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

ATTN...WFO...LCH...SHV...HGX...FWD...

LAT...LON   30959467 31069783 32299688 33079610 33159418 32819322
            31549374 30959467

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 8, 8:01 PM CDT	Mesoscale Discussion	SPC	Brown, Callahan, Coke, Coleman, Concho, Cooke and 29 more	89 min
May 9, 2:39 AM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Borden, Clay, Cooke, Fisher and 21 more	3 hr
May 9, 1:39 PM CDT	Mesoscale Discussion	SPC	Bowie, Cooke, Delta, Fannin, Grayson, Lamar and 1 more	66 min
May 9, 2:36 PM CDT	Tornado Watch	SPC	Bowie, Cooke, Delta, Fannin, Grayson, Lamar and 1 more	7 hr
May 9, 5:49 PM CDT	Mesoscale Discussion	SPC	Bowie, Delta, Fannin, Lamar, Red River	56 min

Nearby

Mesoscale Discussions in Texas, 2016 Mesoscale Discussions in Louisiana, 2016 Every mesoscale discussion in 2016

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.