ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 200841
   SPC AC 200841

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0341 AM CDT Thu Sep 20 2018

   Valid 231200Z - 281200Z

   ...DISCUSSION...
   Latest runs of the medium-range models appear to be in good general
   agreement through Day 6 (Tuesday 9-25), after which differences
   begin to gradually emerge, complicating attempts to ascertain
   convective potential through the middle of next week.

   Prior to this, models consistently depict that the trough moving
   across the Pacific Northwest at the start of Day 4 will gradually
   expand/deepen as it moves across the western and into the central
   U.S. through Day 6.  In response to the approaching trough, a cold
   front is progged to move into the northern and central Plains Day 4,
   and the across the Plains and into the Upper Great Lakes Day 5.  Day
   6, as the upper system continues to expand/advance eastward, the
   front is forecast to cross the Upper Great Lakes/Midwest/southern
   Plains.

   As the front crosses the central and eastern U.S., an increase in
   convective potential will accompany it.  However, in general, it
   appears that the stronger flow aloft will be confined to northern
   portions of the frontal zone, where warm-sector instability will
   likely remain more limited.  While portions of the central Plains
   and upper Midwest on Monday the 24th (Day 5), and the upper Great
   Lakes and Midwest on Tuesday the 25th (Day 6), may require attention
   in later outlooks, once any potential risk becomes more certain, no
   areas will be issued at this time.

   ..Goss.. 09/20/2018

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Data courtesy the Storm Prediction Center