SPC MD 1275

MD 1275 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL IL TO WESTERN IN

Mesoscale Discussion 1275
NWS Storm Prediction Center Norman OK
0646 AM CDT Mon Jul 10 2017

Areas affected...Central IL to western IN

Concerning...Severe potential...Watch unlikely 

Valid 101146Z - 101345Z

Probability of Watch Issuance...20 percent

SUMMARY...Locally strong wind gusts will be possible this morning,
though the overall potential for damaging gusts appears to be
waning, as the remnants of a bowing line of storms advance across
central IL through 13-14Z, reaching western IN around 14Z.  WW
issuance is unlikely at this time downstream across central IL into
western IN.

DISCUSSION...Trends in the forward movement of a bowing line across
central IL (La Salle to Fulton counties) have begun to show
indications of deceleration.  A strong rear-inflow jet (50 kt
between 2-5 km agl at WSR-88D DVN) was observed with this bowing
line of storms and a 40-45 kt westerly low-level jet extended into
central IL per ILX VAD.  Despite these favorable kinematics, an
extensive area of cloudiness/embedded rain located immediately
downstream of the bowing line into northeast and east-central IL to
northwest IN will limit boundary layer heating/destabilization this
morning.  Further indication of a waning severe weather threat in
the short term is an overall decrease in lightning coverage with the
ongoing storms moving into and through central IL.  

Models and water vapor imagery depicted a progressive midlevel
impulse with the ongoing MCS, now moving through northern and
central IL.  Low-level westerlies may weaken a little this morning,
though have magnitudes around 40 kt, with restrengthening this
afternoon across the lower OH Valley. Forcing for ascent attendant
to the midlevel impulse and warm-air advection along the low-level
jet will support additional convective development/embedded
thunderstorms spreading to the east. Locally strong wind gusts
cannot be ruled out with any stronger storms, though the overall
coverage of stronger storms is expected to remain low through the
morning.

..Peters/Guyer.. 07/10/2017

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

ATTN...WFO...IWX...IND...LOT...ILX...DVN...

LAT...LON   40479063 40958984 41248846 41238775 40768697 40068691
            39558741 39508829 39848958 40039041 40129067 40479063 

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