278  
ACUS11 KWNS 171832  
SWOMCD  
SPC MCD 171832  
TXZ000-172030-  
 
MESOSCALE DISCUSSION 0838  
NWS STORM PREDICTION CENTER NORMAN OK  
0132 PM CDT SAT MAY 17 2025  
 
AREAS AFFECTED...2CENTRAL TO SOUTHERN TEXAS  
 
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE  
 
VALID 171832Z - 172030Z  
 
PROBABILITY OF WATCH ISSUANCE...60 PERCENT  
 
SUMMARY...THUNDERSTORM DEVELOPMENT APPEARS LIKELY BASED ON RECENT  
SATELLITE TRENDS, AND WILL DEVELOP IN AN ENVIRONMENT VERY CONDUCIVE  
FOR SEVERE CONVECTION. WATCH ISSUANCE IS PROBABLE AS THUNDERSTORM  
COVERAGE/INTENSITY BEGINS TO INCREASE.  
 
DISCUSSION...LATEST GOES VISIBLE IMAGERY SHOWS STEADILY GROWING  
CONGESTUS ALONG A CONFLUENCE AXIS/DIFFERENTIAL HEATING BOUNDARY  
DRAPED FROM CENTRAL TX TO THE RIO GRANDE AND ON THE NORTHERN SLOPES  
OF THE SIERRA DEL CARMEN RANGE IN NORTHERN MEXICO. AHEAD OF THE  
BUILDING CUMULUS FIELD, HIGH-QUALITY MOISTURE (DEWPOINTS IN THE MID  
70S) AND TEMPERATURES WARMING INTO THE LOW TO MID 90S ARE SUPPORTING  
MLCAPE VALUES UPWARDS OF 3000 J/KG. DESPITE WEAK LOW-LEVEL WINDS,  
INCREASING MID-LEVEL FLOW AHEAD OF AN APPROACHING SPEED MAX IS  
SUPPORTING EFFECTIVE SHEAR VALUES ON THE ORDER OF 45 TO 55 KNOTS.  
THIS CONVECTIVE ENVIRONMENT IS VERY FAVORABLE FOR ORGANIZED  
SUPERCELLS AND MAY SUPPORT SEVERE GUSTS AND HAIL AS LARGE AS 2 TO 3  
INCHES IN DIAMETER. WEAK FORCING FOR ASCENT CASTS SOME UNCERTAINTY  
ON STORM COVERAGE, BUT RECENT HIGH-RES GUIDANCE CONTINUES TO SUGGEST  
RAPID THUNDERSTORM DEVELOPMENT IS LIKELY BETWEEN 20-22 UTC BOTH  
ALONG THE BOUNDARY AND OFF THE NORTHERN MEXICO MOUNTAINS. CONVECTIVE  
TRENDS WILL CONTINUE TO BE MONITORED AND WATCH ISSUANCE IS PROBABLE  
AS DEEP CONVECTION BEGIN TO DEVELOP.  
 
..MOORE/HART.. 05/17/2025  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...FWD...EWX...SJT...  
 
LAT...LON 29710143 31070032 31749947 31909895 31789848 31509813  
31159803 30839807 30579821 30469832 30189866 29069998  
28870030 28760048 28900066 29120076 29340098 29450116  
29540133 29630148 29710143  
 
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH  
MOST PROBABLE PEAK WIND GUST...65-80 MPH  
MOST PROBABLE PEAK HAIL SIZE...2.75-4.25 IN  
 
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