563
ACUS11 KWNS 131943
SWOMCD
SPC MCD 131942
IAZ000-MNZ000-SDZ000-NEZ000-132115-
MESOSCALE DISCUSSION 0400
NWS STORM PREDICTION CENTER NORMAN OK
0242 PM CDT MON APR 13 2026
AREAS AFFECTED...PORTIONS OF NORTHEASTERN NEBRASKA INTO FAR
SOUTHEASTERN SOUTH DAKOTA...EXTREME SOUTHWESTERN MINNESOTA...AND
EXTREME NORTHWESTERN IOWA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 131942Z - 132115Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...THE SEVERE THREAT SHOULD GENERALLY INCREASE NORTH OF A
SURFACE LOW OVER PORTIONS OF NORTHERN NE INTO FAR SOUTHEASTERN SD
OVER THE NEXT FEW HOURS. CONVECTIVE TRENDS ARE BEING MONITORED FOR
THE NEED OF A WW ISSUANCE.
DISCUSSION...LOW 60S F SURFACE DEWPOINTS ARE PIVOTING AROUND AND TO
THE NORTH OF A SURFACE LOW OVER CENTRAL NE, WHICH IS BOOSTING MLCAPE
OVER 2000 J/KG GIVEN 8-9 C/KM MID-LEVEL LAPSE RATES IN PLACE (PER
19Z MESOANALYSIS AND AN 18Z OAX OBSERVED SOUNDING). AGITATED CU IS
DEVELOPING ALONG THE NE/SD BORDER, WHERE MLCINH APPEARS TO BE
RAPIDLY ERODING. THE OAX OBSERVED SOUNDING SHOWS AN ELONGATED
HODOGRAPH WITH MODEST LOW-LEVEL CURVATURE, AND THE 19Z MESOANALYSIS
DEPICTS OVER 50 KTS OF EFFECTIVE BULK SHEAR, SUGGESTING SUPERCELL
STORM MODES. OCCASIONAL RUNS OF SOME HIGH-RESOLUTION GUIDANCE
MEMBERS HAVE DEPICTED THE INITIATION OF STOUT, LONG-LIVED SUPERCELL
STRUCTURES ORIGINATING FROM THIS MESOSCALE SCENARIO.
AS MLCINH CONTINUES TO ERODE, SUPERCELLS SHOULD DEVELOP OVER THE
NEXT FEW HOURS, ACCOMPANIED BY A SEVERE HAIL THREAT. SIGNIFICANT
SEVERE HAIL IS POSSIBLE, WITH 2-3 INCH STONES POSSIBLE, AND AN
INSTANCE OF 4+ INCH DIAMETER HAIL CANNOT BE COMPLETELY RULED OUT.
FURTHERMORE, ANY STORMS THAT CAN ANCHOR TO THE WARM FRONT AHEAD OF
THE SURFACE LOW MAY BE ACCOMPANIED BY A TORNADO THREAT. CONVECTIVE
TRENDS WILL CONTINUE TO BE MONITORED FOR THE NEED OF A WW ISSUANCE.
..SQUITIERI/HART.. 04/13/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...FSD...OAX...LBF...
LAT...LON 42379819 41969910 41899934 41969948 42159945 42499918
42989881 43549813 43649762 43629682 43549640 43349614
43089605 42819626 42689668 42649736 42499783 42379819
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN
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