Sunday, July 1, 2018

Mesoscale Discussion for McHenry Co., IL

<pre>ACUS11 KWNS 011723 SWOMCD

Mesoscale Discussion 0974 NWS Storm Prediction Center Norman OK 1223 PM CDT Sun Jul 01 2018

Areas affected…Northern and Central Illinois and Far Northwest Indiana.

Concerning…Severe potential…Watch likely

Valid 011723Z – 011900Z

Probability of Watch Issuance…80 percent

SUMMARY…Strong to severe storms are expected this afternoon across northern and central Illinois. The primary threat from these storms will be damaging wind gusts.

DISCUSSION…Temperatures have risen into the mid to upper 80s across much of Illinois with dewpoints in the upper 70s. This has led to MLCAPE around 2500 J/kg. Additional destabilization is expected through the afternoon as surface heating continues. Storms are expected to form along the cold front (currently in eastern Iowa and Eastern Missouri) and move eastward through the afternoon. Flow is relatively weak on the ILX 12Z sounding, however, low-level flow is forecast to increase to 35 to 40 knots by mid-afternoon. This will lead to a marginal shear environment with effective shear around 25 to 30 knots with most of this shear focused in the lowest 1 to 2 km. Nearly parallel orientation of the cold front to the deeper level flow will limit a greater severe weather threat, however, more robust updrafts could mix down stronger winds, posing a damaging wind threat through the afternoon. The threat will be maximized with any bowing segments which can orient more normal to the low-level flow and accelerate northeastward. A severe thunderstorm watch is likely in the next hour or two to cover this severe wind threat.

..Bentley/Hart.. 07/01/2018

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

ATTN…WFO…LOT…ILX…LSX…DVN…

LAT…LON 41259061 41869004 42429011 42488919 42478857 42468797

42298775 41838752 41418740 40568757 39678784 38758904  38869001 39209059 39809127 40929100 41259061 </pre>

https://wxn.io/CcnrJ ------------------------------------------------ © Copyleft 2018 WxNotify. All wrongs reserved.

You may unsubscribe from WxNotify e-mails by going to https://wxnotify.com/signin.html and removing the corresponding alert.