Mesoscale Discussion 0474
NWS Storm Prediction Center Norman OK
0845 PM CDT Fri Apr 18 2025
Areas affected...portions of central into northern Lower Michigan
Concerning...Severe potential...Watch unlikely
Valid 190145Z - 190315Z
Probability of Watch Issuance...20 percent
SUMMARY...A couple instances of hail (some perhaps exceeding 1 inch
in diameter) are possible with the stronger, longer-lived storms
through the evening hours.
DISCUSSION...Thunderstorms continue to gradually increase in
coverage and intensity within a low-level warm-air advection regime,
north of the warm sector. The 00Z APX observed sounding depicts a
thin but long CAPE profile above 700 mb, with 8 C/km mid-level lapse
rates supporting near 1000 J/kg MUCAPE. The observed hodograph above
700 mb is elongated and straight, indicating strong speed shear in
the mid-levels of the troposphere. As such, hail is possible with
some of the stronger storms. The narrow constriction of CAPE in the
buoyant layer suggests that maximum hail size may also be relatively
limited, but may still exceed marginally severe thresholds in spots.
Nonetheless, given the expected isolated nature of the severe hail
threat, a WW issuance is not expected.
..Squitieri/Guyer.. 04/19/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DTX...APX...GRR...
LAT...LON 43988658 44548586 44748476 44628364 44368343 44048385
43778403 43498458 43398547 43518647 43988658
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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