762
ACUS11 KWNS 212252
SWOMCD
SPC MCD 212252
CAZ000-220045-
MESOSCALE DISCUSSION 0495
NWS STORM PREDICTION CENTER NORMAN OK
0552 PM CDT TUE APR 21 2026
AREAS AFFECTED...PARTS OF SAN JOAQUIN VALLEY
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 212252Z - 220045Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...INTENSIFYING STORMS TO THE WEST THROUGH NORTHWEST OF
FRESNO MIGHT BECOME SUPPORTIVE OF THE DEVELOPMENT OF ANOTHER TORNADO
OR TWO THROUGH 4-6 PM PDT.
DISCUSSION...THE LOW-TOPPED SUPERCELL WITH REPORTED TORNADO TO THE
WEST-NORTHWEST OF FRESNO, EARLIER, APPEARED TO HAVE BEEN SUPPORTED
BY FORCING FOR ASCENT TO THE NORTHEAST OF A CYCLONIC MID-LEVEL
VORTICITY CENTER NOW MIGRATING INTO THE SOUTHERN SIERRA, BENEATH
WHICH LOW-LEVEL CONVERGENCE AND AMBIENT VERTICAL VORTICITY BECAME
LOCALLY ENHANCED BY THE STRENGTHENING THUNDERSTORM DEVELOPMENT.
NEW THUNDERSTORM DEVELOPMENT IS CURRENTLY INTENSIFYING A BIT FURTHER
TO THE WEST, TO THE SOUTHWEST OF MADERA, AS THE BOUNDARY-LAYER
BEGINS TO REACH PEAK AFTERNOON INSTABILITY, AIDED BY INSOLATION
BENEATH COLD AIR ASSOCIATED WITH MID-LEVEL TROUGHING OVERSPREADING
MUCH THE CALIFORNIA COAST THROUGH THE SIERRA NEVADA. THIS ACTIVITY
REMAINS JUST TO THE NORTH OF CYCLONIC CURVED 50-70 KT WESTERLY 500
MB JET NOSING INLAND THROUGH THE SOUTHERN GREAT BASIN.
BASED ON LATEST SURFACE OBSERVATIONS AND MESOANALYSIS, IT APPEARS
THAT A CORRIDOR OF ENHANCED LOW-LEVEL CONVERGENCE IS BEING
MAINTAINED NEAR AND TO THE NORTHWEST THROUGH NORTH OF FRESNO, WHICH
COULD SUPPORT THE SPIN-UP OF ANOTHER TORNADO OR TWO WITH A
STRENGTHENING LOW-LEVEL MESOCYCLONE.
..KERR/GLEASON.. 04/21/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...HNX...
LAT...LON 37402050 37662000 36991936 36521951 36541999 36642042
37402050
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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