Mesoscale Discussion 307

Issued

Mar 29, 2011, 5:59 PM CDT (22:59 UTC)

Expired

Mar 29, 2011, 8:00 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

The Laughlin AFB radar (KDFX), 129 km from the middle of the area, began a volume at 23:02 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.

414 
ACUS11 KWNS 292300
SWOMCD
SPC MCD 292259
TXZ000-300100-

MESOSCALE DISCUSSION 0307
NWS STORM PREDICTION CENTER NORMAN OK
0559 PM CDT TUE MAR 29 2011

AREAS AFFECTED...PORTIONS SW/S-CENTRAL TX...PRIMARILY SRN HILL
COUNTRY AND EDWARDS PLATEAU TO MIDDLE RIO GRANDE VALLEY AND COASTAL
BEND

CONCERNING...SEVERE THUNDERSTORM WATCH 73...

VALID 292259Z - 300100Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 73
CONTINUES.

CONVECTIVE COVERAGE FCST TO INCREASE NEXT FEW HOURS ALONG/AHEAD OF
SFC COLD FRONT OVER THIS REGION AS FRONT IMPINGES ON HIGHER-THETAE
WARM SECTOR OVER S TX...LARGE HAIL AND OCNL DAMAGING GUSTS EXPECTED.


LAST SFC MESOANALYSIS SHOWED COLD FRONT FROM NEAR GTU WSWWD ACROSS
EDWARDS/VAL VERDE COUNTIES...AND CROSSING RIO GRANDE S OF
6R6...MOVING SSEWD AT ABOUT 15 KT.  S OF FRONT...CONVECTION
CONTINUES TO FORM OVER SERRANIAS DEL BURRO RANGE IN COAHUILA...BUT
GENERALLY HAS BEEN WEAKENING AFTER MOVING E OF MOUNTAINS AND AWAY
FROM OROGRAPHIC FORCING SOURCE.  STILL...CINH MAY BE WEAK ENOUGH TO
ALLOW ONE OR TWO SUCH TSTMS TO ACQUIRE SUSTAINED ROTATION AND REACH
RIO GRANDE AFTER 00Z...ESPECIALLY ANY LEFT-MOVERS OR BOWS THAT MAY
FORM.  DEEP-LAYER VERTICAL WIND PROFILES REMAIN FAVORABLE WITH 40-50
KT EFFECTIVE SHEAR.  PRONOUNCED COUNTERCLOCKWISE CURVATURE IN
PREFRONTAL/LOW-LEVEL HODOGRAPHS...BOTH AS OBSERVED IN DFX VWP AND AS
PREDICTED REASONABLY WELL BY RUC FCST SOUNDINGS...YIELDS FAR MORE
NEGATIVE THAN POSITIVE SRH FOR ALL BUT EXTREMELY DEVIANT/FAST
RIGHT-MOVERS...WHICH ARE UNLIKELY EXCEPT WHERE OUTFLOW-DOMINANT.

ADDITIONAL TSTMS DEVELOPING N OR NE OF MEX MOUNTAINS MAY BE UNDERCUT
BY ZONAL SEGMENT OF COLD FRONT SOON THEREAFTER...AS HAS ISOLATED
CELL OVER VAL VERDE COUNTY.  CONVECTION APPEARS TO BE DEEPENING
FARTHER ENE ALONG MORE SW-NE ALIGNED FRONTAL SEGMENT FROM
EDWARDS-LLANO COUNTIES AS OF 2230Z.  THIS ACTIVITY MAY HAVE ACCESS
TO WARM-SECTOR AIR MASS FOR MORE SUSTAINED PERIOD...ESPECIALLY ANY
TSTMS THAT CAN AVOID ACQUIRING LEFT-MOVING SUPERCELLULAR
CHARACTERISTICS AND MOVE EWD/SEWD AT LEAST IN STEP WITH BOUNDARY
TRANSLATION.  MOST STORM MOTIONS NEAR FRONT SHOULD BE CLOSE TO
HODOGRAPH...WITH FRONTAL FORCING EVENTUALLY CONTRIBUTING TO DOMINANT
QUASI-LINEAR CONVECTIVE MODE.

..EDWARDS.. 03/29/2011

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

ATTN...WFO...HGX...CRP...EWX...BRO...

LAT...LON   27279741 27279948 27579950 27669967 27789985 27979995
            28160010 28270032 29120068 29150080 29260078 29750141
            29770176 30190094 30259699 28189666 27709713 27439731
            27279741

Mesoscale Discussions in Texas, 2011Every mesoscale discussion in 2011

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.