SPC MD 1176
[html]MD 1176 CONCERNING SEVERE POTENTIAL...TORNADO WATCH LIKELY FOR NORTHEAST IA...EXTREME SOUTHEAST MN...PORTIONS OF SOUTHERN/CENTRAL WI AND EXTREME NORTHWEST IL
Mesoscale Discussion 1176
NWS Storm Prediction Center Norman OK
0122 PM CDT Wed Jun 15 2022
Areas affected...northeast IA...extreme southeast MN...portions of
southern/central WI and extreme northwest IL
Concerning...Severe potential...Tornado Watch likely
Valid 151822Z - 152015Z
Probability of Watch Issuance...95 percent
SUMMARY...c*nvection is expected to develop across northeast IA and
spread northeast in the next couple of hours. Tornadoes, damaging
gusts and hail will all be possible. A tornado watch will likely be
needed by 20z.
DISCUSSION...Visible satellite and radar data from KDMX indicate
deepening cumulus across northeast IA to the northeast of a surface
low and in the vicinity of a surface warm front. More isolated
cumulus has also started to develop across southern WI. Latest water
vapor imagery indicates a shortwave impulse now ejecting across
eastern NE/southeast SD will lift east/northeast, providing
increasing ascent across the region within the next couple of hours.
Some weak inhibition likely remains in the vicinity of the surface
boundary, though continued heating and increasing ascent should
rapidly erode any remaining inhibition over the next hour.
Strong heating south of the surface boundary across IA into central
WI has allowed temperatures to warm into the mid/upper 80s amid
upper 60s to low 70s F dewpoints. Relatively warm temperatures
between 850-700 mb will maintain modestly steep midlevel lapse
rates, but the very moist boundary layer is still supporting
moderate instability across the region. Effective shear magnitudes
greater than 50 kt will further support robust, well-organized
convection. Some uncertainty remains with regards to convective
mode, but semi-discrete supercells appear possible at least
initially in convective evolution. VWP data from KARX already shows
enlarged, favorably curved low-level hodographs supporting rotation.
Additionally, strong low-level instability with enhance vorticity in
the vicinity of the surface front suggests increased tornado
potential will acco*pany any semi-discrete convection.
With time, convection is expected to grow upscale as a 35+ kt
south/southwesterly low-level jet increases by late afternoon/early
evening. This will result in an increasing risk for more widespread
damaging gusts, though mesovortex tornadoes also will continue to be
possible given favorable low-level shear.
..Leitman/Guyer.. 06/15/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GRB...LOT...MKX...DVN...ARX...DMX...
LAT...LON 42379320 42699312 42819308 43229273 43729207 43959172
44359099 44549056 44709020 44658991 44558962 44348923
44028883 43758870 43448859 42978862 42668883 42328935
42009017 41809157 41809233 41919281 42119309 42379320
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Source: SPC MD 1176 (http://ht**://www.spc.noaa.gov/products/md/md1176.html)