Mesoscale Discussion 970

Issued

Jun 12, 2014, 8:51 AM CDT (13:51 UTC)

Expired

Jun 12, 2014, 9:45 AM CDT

In force

54 min

Issued by

the Storm Prediction Center

Chance of a watch

40%

The Shreveport radar (KSHV), 140 km from the middle of the area, began a volume at 13:52 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.

088 
ACUS11 KWNS 121351
SWOMCD
SPC MCD 121351 
LAZ000-TXZ000-121445-

MESOSCALE DISCUSSION 0970
NWS STORM PREDICTION CENTER NORMAN OK
0851 AM CDT THU JUN 12 2014

AREAS AFFECTED...EAST/NORTHEAST TX...NORTHWEST LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 121351Z - 121445Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...CONVECTIVE TRENDS ARE INCREASING IN ASSOCIATION WITH AN
OUTFLOW BOUNDARY PROGRESSING SEWD. PRIMARY THREAT INITIALLY APPEARS
TO BE LARGE HAIL GIVEN THE PRESENCE OF A STABLE BOUNDARY LAYER.
TRENDS WILL CONTINUE TO BE MONITORED FOR A WW...WHICH MAY BECOME
MORE PROBABLE INTO THE LATE MORNING.

DISCUSSION...RADAR MOSAIC IMAGERY SHOWS INCREASING CONVECTIVE TRENDS
ALONG AN OUTFLOW BOUNDARY ASSOCIATED WITH A DECAYING MCS OVER N TX.
THE STRONGEST STORMS AS OF 1345Z WERE LOCATED OVER VAN ZANDT AND
KAUFMAN COUNTIES TX. BOTH SHV AND FWD RAOBS SAMPLED AN AIR MASS
CONDUCIVE FOR VERY LARGE HAIL PRODUCTION...CHARACTERIZED BY STEEP
MIDLEVEL LAPSE RATES AND RICH BOUNDARY LAYER MOISTURE...YIELDING
MUCAPE VALUES OF 2500-4000 J/KG. THE PRIMARY LIMITING FACTOR APPEARS
TO BE VEERING BUT WEAK DEEP-LAYER FLOW...BUT THIS SHOULD STILL BE
SUFFICIENT FOR AT LEAST MARGINAL STORM ORGANIZATION. 

CURRENT THINKING IS THAT THE INITIAL THREAT ASSOCIATED WITH THIS
ACTIVITY WILL BE LARGE HAIL THROUGH THE MID-LATE MORNING.
HOWEVER...AS DIURNAL HEATING BECOMES MORE SUPPORTIVE FOR SFC-BASED
CONVECTION /AS TEMPERATURES WARM INTO THE MID-80S F/...THE POTENTIAL
FOR DMGG WINDS AND PERHAPS A TORNADO OR TWO SHOULD INCREASE...WITH
THE FORMER THREAT ENHANCED IF CONVECTION CAN EVOLVE INTO SMALL
LINE/BOWING SEGMENTS. TRENDS WILL BE MONITORED FOR INCREASING SVR
POTENTIAL THROUGH THE LATE MORNING...WHICH MAY REQUIRE WW ISSUANCE
ACROSS EAST/NORTHEAST TX AND NORTHWEST LA.

..ROGERS/GUYER.. 06/12/2014

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

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

LAT...LON   33239557 33169427 32539360 31509317 31069362 30759522
            30969643 31299726 32189750 33239557

Mesoscale Discussions in Texas, 2014Mesoscale Discussions in Louisiana, 2014Every mesoscale discussion in 2014

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.