Alert archive / Texas / Mesoscale Discussions in 2009

Mesoscale Discussion 710

May 5, 200912 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 5, 2009, 3:06 PM CDT for 12 counties in Texas. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: May 5, 2009, 3:06 PM CDT (20:06 UTC)
Expired: May 5, 2009, 4:00 PM CDT
In force: 54 min
Issued by: the Storm Prediction Center

Counties Callahan County, TX, Coleman County, TX, Eastland County, TX, Jones County, TX, Nolan County, TX, Palo Pinto County, TX, Runnels County, TX, Shackelford County, TX, Stephens County, TX, Taylor County, TX, Throckmorton County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 8 km from the middle of the area, began a volume at 20:10 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 247May 5, 5:45 PM CDT

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 8.1 hours before the alert went out and 194 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: 164 J/kg
Mixed-layer CIN: -169 J/kg
Mixed-layer LCL: 560 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 170 m²/s²
0-3 km storm-relative helicity: 268 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 8.1

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 052006
SWOMCD
SPC MCD 052006 
TXZ000-052100-

MESOSCALE DISCUSSION 0710
NWS STORM PREDICTION CENTER NORMAN OK
0306 PM CDT TUE MAY 05 2009

AREAS AFFECTED...PARTS OF W-CNTRL AND W N-CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 052006Z - 052100Z

TSTM INITIATION/SEVERE POTENTIAL INCREASING.  CONVECTIVE INITIATION
POSSIBLE BY LATE AFTERNOON.

RECENT SURFACE MESOANALYSIS SHOWS A TRIPLE POINT FEATURE 55 MI W ABI
WITH A N-S DRYLINE AND A WARM FRONT ELONGATED IN A GENERAL W-E
ORIENTATION THROUGH THE DFW METROPLEX.  A LOCALIZED PRESSURE FALL
MAXIMA HAS BEEN OBSERVED /1-2 MB PER HR/ TO THE E OF THE TRIPLE
POINT.  A LOW LEVEL THERMAL RIDGE /STEEPENING 0-2 KM LAPSE RATE
PLUME/ EXTENDING NEWD TOWARDS THIS FEATURE...ALONG WITH ENHANCED LOW
LEVEL CONVERGENCE INVOF WARM FRONT MAY BE ENOUGH TO BREAK A WEAKENED
CAP OVER THIS AREA.  

VERY UNSTABLE AIRMASS /AOA 2500 J/KG MLCAPE/...SIZEABLE CLOCKWISE
CURVED LOW LEVEL HODOGRAPHS /PER DYX VWP/ BENEATH MORE THAN ADEQUATE
DEEP FLOW ALOFT WILL PROMOTE RAPID SUPERCELL DEVELOPMENT IF A STORM
INITIATES.  VERY LARGE HAIL WILL BE A DISTINCT
POSSIBILITY...INCLUDING THE POTENTIAL FOR TORNADO/S...ALONG WITH
DMGG WIND GUSTS.  IF/ONCE STORM INITIATION APPEARS IMMINENT...A WW
WILL BE NEEDED.

..SMITH.. 05/05/2009

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

ATTN...WFO...FWD...SJT...LUB...

LAT...LON   31579970 31910043 32660042 33010007 33289950 33319854
            33009802 32509813 32149875 31579970

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 5, 6:40 AM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Childress, Clay, Collingsworth, Foard and 12 more	2 hr
May 5, 12:21 PM CDT	Mesoscale Discussion	SPC	Delta, Fannin, Franklin, Grayson, Hopkins, Lamar and 2 more	84 min
May 5, 1:38 PM CDT	Severe Thunderstorm Watch	SPC	Bowie, Camp, Cass, Delta, Fannin, Franklin and 13 more	4 hr
May 5, 3:53 PM CDT	Mesoscale Discussion	SPC	Bowie, Cass, Red River	97 min
May 5, 5:13 PM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Callahan, Coleman, Comanche, Eastland and 14 more	62 min
May 5, 5:46 PM CDT	Tornado Watch	SPC	Bosque, Brown, Callahan, Coke, Coleman, Comanche and 20 more	6 hr

Nearby

Mesoscale Discussions in Texas, 2009 Every mesoscale discussion in 2009

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.