409  
ACUS11 KWNS 211446  
SWOMCD  
SPC MCD 211445  
ARZ000-OKZ000-211645-  
 
MESOSCALE DISCUSSION 0535  
NWS STORM PREDICTION CENTER NORMAN OK  
0945 AM CDT FRI APR 21 2017  
 
AREAS AFFECTED...CENTRAL INTO SOUTHEAST OK  
 
CONCERNING...SEVERE THUNDERSTORM WATCH 153...  
 
VALID 211445Z - 211645Z  
 
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 153  
CONTINUES.  
 
SUMMARY...DAMAGING WIND THREAT WILL SPREAD EAST-SOUTHEASTWARD  
THROUGH THE MORNING AHEAD OF FAST MOVING CONVECTIVE SYSTEM. WATCH  
ISSUANCE DOWNSTREAM IS IMMINENT.  
 
DISCUSSION...AT 1445Z, A FAST-MOVING LINE WAS MOVING  
EAST-SOUTHEASTWARD ACROSS CENTRAL OK. MEASURED WIND GUSTS OF 60-70  
MPH HAVE RECENTLY BEEN OBSERVED IN CONJUNCTION WITH THIS LINE. WHILE  
THE AREA BEING AFFECTED IS PRIMARILY NORTH OF THE WARM FRONT, A  
STRONG PRESSURE RISE/FALL COUPLET (NOTED IN OK MESONET DATA)  
ASSOCIATED WITH THE CONVECTIVE SYSTEM WILL HELP TO MAINTAIN ITS  
INTENSITY AND SUPPORT THE CONTINUED POTENTIAL FOR SEVERE WIND GUSTS  
THROUGH THE REST OF THE MORNING.  
 
SOME UNCERTAINTY REMAINS REGARDING THE SOUTHWARD EXTENT OF THE  
THREAT IN THE SHORT-TERM, BUT AS THE OUTFLOW APPROACHES AREAS NEAR  
AND SOUTH OF THE WARM FRONT ACROSS SOUTHERN OK AND WESTERN AR, SOME  
WIND THREAT MAY EVOLVE IN THOSE AREAS, IN ADDITION TO THE THREAT  
FURTHER NORTH. GIVEN THE WELL-ORGANIZED NATURE OF THE SYSTEM, A NEW  
WATCH WILL BE REQUIRED DOWNSTREAM INTO SOUTHEAST OK AND WESTERN AR.  
 
..DEAN/GOSS.. 04/21/2017  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...LZK...SHV...TSA...OUN...  
 
LAT...LON 34779788 35259740 35579705 36069660 36269559 35999265  
33819326 33879431 34059537 34189650 34359771 34389782  
34539822 34779788  
 
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