Convective Outlook

SPC 0100Z Day 1 Outlook
Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0753 PM CDT Thu Aug 17 2017

Valid 180100Z - 181200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE OKLAHOMA
AND TEXAS PANHANDLES...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE TEXAS
PANHANDLE NORTHWARD INTO SOUTHERN SOUTH DAKOTA...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE THUMB OF
MICHIGAN...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR A SMALL PART
OF WESTERN PENNSYLVANIA...

...SUMMARY...
Isolated storms capable of severe gusts and large hail are possible
over the Texas-Oklahoma Panhandle region this evening.  Other
isolated strong to locally severe storms are possible from western
Kansas into southern South Dakota and in eastern Lower Michigan and
western Pennsylvania.

...Plains...
A belt of moderate west-northwesterly flow is located over the
region this evening ahead of a shortwave trough west of the Black
Hills and is forecast to move through the Dakotas tonight.  The 00Z
AMA and DDC RAOBS showed steep 0-3 km lapse rates (in excess of 8
degrees C/km) within a south-to-north corridor of low-level moisture
characterized by 50s-lower 60s degrees F dewpoints.  A modest
strengthening in a central High Plains LLJ is expected this evening
but nocturnal stabilization will likely confine the strong to
severe-storm risk to this evening.  Isolated bouts of hail/wind will
accompany any supercell or organized/intense multicell.

...Thumb of Michigan and western Pennsylvania...
A shortwave trough over the northern Great Lakes will continue to
move to the northeast into Ontario during the evening.  A couple of
weak/shallow supercells have formed within eastern Lower MI and near
the OH/PA border this evening in a moist but marginally unstable
setup (reference the 00Z DTX and PIT RAOBS).  Stabilization of the
boundary layer will lead to storm weakening during the next hour as
the cluster of storms moves farther east in western PA and into the
Lake Huron coastal area.  Until then, a marginal risk for a
brief/weak tornado may continue for the next 30-60 minutes (prior to
02Z) before diminishing.

..Smith.. 08/18/2017

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Updated 17 August 2017 | 8:00 pm