Mesoscale Discussion 1526
NWS Storm Prediction Center Norman OK
0153 PM CDT Fri Jul 19 2019
Areas affected...much of central Minnesota
Concerning...Severe potential...Tornado Watch likely
Valid 191853Z - 192130Z
Probability of Watch Issuance...95 percent
SUMMARY...Storms are expected to form over west-central Minnesota
around 20-21Z, with supercells possible initially. Tornadoes and
large hail are likely. A damaging wind threat is expected later
today as storms merge into an MCS.
DISCUSSION...The combination of satellite imagery and surface
observations show an east-west oriented outflow boundary across
southern MN, with low pressure over east-central SD into southwest
MN. A very warm, moist, and unstable air mass exists along and south
of the boundary where temperatures continue to rise above 90 F.
While temperatures north of the boundary are relatively cooler,
rapid recovery will occur due to southwest flow just above the
surface combined with mixing. Substantial pressure falls are
occurring over the cooler air, mainly due to warm advection just off
Deep, moist convergence is currently centered over west-central MN,
and this is where several models suggest initiation will occur. This
seems reasonable, especially once warmer temperatures > 90 F arrive.
Backed surface winds are contributing to 0-1 SRH values in excess of
300 m2/s2, with relatively low LCLs near the boundary, and extreme
instability. This will certainly support supercells and tornadoes,
assuming discrete cells. As such, a tornado watch will be needed
soon. Eventually, storms will merge into an MCS with a damaging wind
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 44799463 44799557 44839585 45009599 45579604 45939579
46229522 46259468 46259348 46189281 46009249 45489234
45089237 44729269 44779405 44799463