Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 2249

October 11, 201114 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Oct 11, 2011, 11:57 PM CDT for 14 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Oct 11, 2011, 11:57 PM CDT (04:57 UTC)
Expired: Oct 12, 2011, 2:00 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Archer County, TX, Baylor County, TX, Clay County, TX, Denton County, TX, Hood County, TX, Jack County, TX, Montague County, TX, Palo Pinto County, TX, Parker County, TX, Tarrant County, TX, Throckmorton County, TX, Wichita County, TX, Wise County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 115 km from the middle of the area, began a volume at 05:01 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

Fort Worth, TX (KFWD), launched 00:00Z, 5.0 hours before the alert went out and 122 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: 24 J/kg
Mixed-layer CIN: -224 J/kg
Mixed-layer LCL: 1883 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 36 m²/s²
0-3 km storm-relative helicity: 53 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.

004 
ACUS11 KWNS 120458
SWOMCD
SPC MCD 120457
TXZ000-OKZ000-120700-

MESOSCALE DISCUSSION 2249
NWS STORM PREDICTION CENTER NORMAN OK
1157 PM CDT TUE OCT 11 2011

AREAS AFFECTED...PORTIONS NW AND N-CENTRAL TX.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 120457Z - 120700Z

SMALL CLUSTER OF SVR TSTMS MOVING SEWD 15-20 KT ACROSS PORTIONS
FOARD/WILBARGER/WICHITA COUNTIES MAY CONTINUE TO POSE THREAT FOR
LARGE HAIL FOR ANOTHER FEW HOURS.  SOME POTENTIAL EXISTS FOR UPSCALE
GROWTH...PERHAPS INVOLVING MERGER WITH INITIALLY NON-SVR CONVECTION
TO ITS SE BETWEEN SPS-RPH.  IF THAT OCCURS...STG/ISOLATED DAMAGING
WINDS WOULD BE POSSIBLE.

ACTIVITY WILL BE MOVING SEWD INTO REGIME OF ELEVATED LOW-LEVEL WAA
AND MOISTURE TRANSPORT...SUPPORTED BY EWD-SHIFTING AND
SLOWLY-VEERING LLJ.  MODIFIED FWD RAOB AND RUC SOUNDINGS SUGGEST
MUCAPE REACHING 500-1000 J/KG RANGE...SUPPORTED BY JUXTAPOSITION OF
WAA BENEATH COOLING ALOFT RELATED TO OVHD SHORTWAVE TROUGH THAT IS
EVIDENT IN VWP/PROFILER WIND TRENDS...MOISTURE CHANNEL IMAGERY AND
EXTRAPOLATED 00Z RAOB ANALYSES.  CONVECTION SHOULD REMAIN RATHER
SHALLOW WITH EQUILIBRIUM LEVEL WELL BENEATH 300-MB LEVEL...LIMITING
CAPE DESPITE STEEP 850-500 MB LAPSE RATES.  40-50 KT EFFECTIVE SHEAR
MAGNITUDES ARE EXPECTED IN SUPPORT OF OCNL POTENTIAL FOR STORM
ROTATION ALOFT.

RAOB AND FCST SOUNDINGS ALSO SUGGEST RELATIVELY DRY SUBCLOUD LAYER
ABOVE SHALLOW BUT STRENGTHENING REGIME OF NEAR-SFC STATIC STABILITY.
 WHILE FORMER SUPPORTS DOWNDRAFT ACCELERATION AND WIND
POTENTIAL...LATTER OFFSETS THAT TO CONSIDERABLE EXTENT...GIVEN
MLCINH VALUES EXCEEDING 200 J/KG ACROSS PROSPECTIVE PATH.  THEREFORE
ANY WIND DAMAGE THREAT THAT MAY RESULT FROM
UPSCALE/FORWARD-PROPAGATION DEVELOPMENT SHOULD BE ISOLATED/SPORADIC
INSTEAD OF WELL-ORGANIZED.

..EDWARDS.. 10/12/2011

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

ATTN...WFO...FWD...OUN...SJT...

LAT...LON   33839954 34169910 33869783 33049676 32509734 32239830
            33179925 33839954

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 11, 7:32 PM CDT	Mesoscale Discussion	SPC	Childress, Collingsworth, Cottle, Dickens, Donley, Foard and 8 more	2 hr

Nearby

Mesoscale Discussions in Texas, 2011 Every mesoscale discussion 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; radar from the NEXRAD Level II archive.