[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 132303
SWOMCD
SPC MCD 132302 
LAZ000-TXZ000-140100-

MESOSCALE DISCUSSION 0286
NWS STORM PREDICTION CENTER NORMAN OK
0502 PM CST SUN MAR 13 2005

AREAS AFFECTED...PORTIONS E-CENTRAL/SE TX...W-CENTRAL/NWRN LA S OF
WW 49

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 132302Z - 140100Z

ISOLATED TO WIDELY SCATTERED TSTMS MAY DEVELOP FROM WRN PORTION WW
409 SWWD ALONG PREFRONTAL WIND SHIFT/TROUGH LINE TOWARD AREA JUST
NNE HOU.  ACTIVITY IS EXPECTED TO BE RELATIVELY SHORT-LIVED...BUT
ISOLATED LARGE HAIL MAY OCCUR. WW NOT ANTICIPATED ATTM BUT WILL
CONTINUE TO MONITOR.

SFC MESOANALYSIS SHOWS CYCLONE NWRN LA...COLD FRONT MOVING SEWD
15-20 KT ACROSS NE THROUGH S-CENTRAL TX...AND PREFRONTAL
CONFLUENCE/TROUGH LINE FROM CYCLONE SWWD ACROSS WRN HARRIS COUNTY
TX.  AS LATTER BOUNDARY MOVES EWD -- PERHAPS OVERTAKEN NEXT 2-3
HOURS BY FRONT -- CONVERGENCE WILL REMAIN MAXIMIZED.  THIS IS
EVIDENT ATTM IN CORRESPONDING LINE OF DEEP CU AND TCU SEEN ON VIS
IMAGERY.  VEERED SFC WINDS WILL LIMIT DIRECTIONAL SHEAR AND PREVENT
STRONGER CONVERGENCE.  HOWEVER...40-50 KT FLOW AROUND 6 KM AGL -- AS
OBSERVED IN E TX/LA PROFILERS AND REGIONAL VWP -- WILL CONTRIBUTE
SUFFICIENT DEEP-LAYER SHEAR FOR SOME HAIL POTENTIAL IN MOST VIGOROUS
UPDRAFTS.  MODIFIED RUC SOUNDINGS SUGGEST 1500-1800 MLCAPE IN THIS
REGIME.

MAIN CONCERN IS SHORT TIME WINDOW FOR OPTIMAL SFC-BASED INSTABILITY
NOW THAT DIABATIC HEATING HAS PASSED PEAK.  SUNSET WILL RESULT IN
DECOUPLING OF NEAR-SFC LAYER AND LARGE INCREASE IN SBCIN.  STRONG
CAPPING SHOULD PREVENT SIGNIFICANT CONVECTION FARTHER S OR SW ALONG
FRONT OR PREFRONTAL BOUNDARY...AND LIMIT COVERAGE OF TSTMS OVER
DISCUSSION AREA.

..EDWARDS.. 03/13/2005

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

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

31519253 31209291 30529411 30099512 30169547 30359532
30989459 31629378 

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