|Mesoscale Discussion 1323|
< Previous MD Next MD >
Mesoscale Discussion 1323
NWS Storm Prediction Center Norman OK
0206 PM CDT Sun Jul 16 2017
Areas affected...Central Illinois...northeastern Missouri...and far
Concerning...Severe potential...Watch unlikely
Valid 161906Z - 162000Z
Probability of Watch Issuance...20 percent
SUMMARY...Convection increasing in portions of west-central Illinois
and vicinity should remain sparse enough to preclude a WW issuance,
although trends will be monitored into the early evening.
DISCUSSION...A cluster of storms was gradually increasing in
intensity across far southeastern Iowa/west-central Illinois over
the past hour. These storms were located along and just ahead of a
cold front migrating southward into the northern portions of the
discussion area. Strong insolation has warmed low-level
temperatures into the low 90s F beneath modestly steep mid-level
lapse rates (around 7.5 deg C/km), resulting in strong instability.
Favorable deep shear profiles will favor organized updrafts, and at
least an isolated risk for large hail and damaging wind gusts will
exist as storms propagate southeastward through an axis of strong
instability downstream across central Illinois.
Despite this strong instability and well-focused low-level forcing
for ascent (along the front), a couple of negating factors may keep
the overall coverage of storms isolated enough to preclude a WW
1) subtle convective inhibition (in the 700-800mb layer) and 2) a
lack of forcing aloft, with subtle height rises/shortwave ridging
currently located across the region. A more substantial shortwave
trough will migrate southeastward across the Great Lakes through the
afternoon, but this trough may remain too far displaced from ongoing
activity to instigate a more widespread threat.
Convective coverage is currently expected to be a bit too sparse to
necessitate a WW issuance at this time, although trends will
continue to be monitored.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 40619226 40819185 40939125 40919052 40838974 40658899
40348842 39878797 39358773 38868782 38598886 38529012
38849130 39479201 40019228 40619226
Top/All Mesoscale Discussions/Forecast Products/Home