SPC MD 781
MD 0781 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF NORTHERN OKLAHOMA

Mesoscale Discussion 0781
NWS Storm Prediction Center Norman OK
1010 PM CDT Mon May 18 2026

Areas affected...portions of northern Oklahoma

Concerning...Severe potential...Watch possible 

Valid 190310Z - 190445Z

Probability of Watch Issuance...60 percent

SUMMARY...The severe threat may increase over northern OK over the
next few hours as storms back-build southwestward along a southward
drifting cold front. Severe gusts are the main threat, though an
instance or two of hail or a tornado are possible. Convective trends
are being monitored for the need of a WW issuance.

DISCUSSION...Robust multicellular convection, with a history of
measured severe gusts, has been steadily back-building
west-southwestward along and immediately behind a southward sagging
cold front. Despite weak upper support, strong low-level convergence
has been supporting persistent convective development, especially
given a 50 kt southerly low-level jet bisecting the cold front
nearly perpendicularly. Ahead of the front, upper 60s F surface
dewpoints beneath 8-9 C/km mid-level lapse rates are yielding 3000+
J/kg MLCAPE per the 00Z OUN/LMN soundings and 02Z mesoanalysis.
These same data sources also depict sizeable low-level hodographs
with 300 m2/s2 effective SRH and 40+ kts of effective bulk shear. As
such, the ambient environment clearly supports severe potential.

The primary uncertainty is how far southwest convection will
initiate along the southward-sagging front, and the timing for
storms to propagate into OK. The current thinking is that storms
capable of severe gusts will eventually propagate southward into
north-central and northeast OK. An instance or two of severe hail
could accompany the stronger storm cores, and a tornado cannot be
ruled out if a robust updraft can outpace the cold front. Convective
trends will continue to be monitored for convective propagation into
OK.

..Squitieri/Mosier.. 05/19/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...TSA...OUN...

LAT...LON   36779919 36929821 36999709 36969623 36739582 36449572
            36099589 35879664 35809745 35909809 36089856 36429904
            36779919 

MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN

Read more
https://www.spc.noaa.gov/products/md/md0781.html