Sep 30, 2017 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Sat Sep 30 07:32:54 UTC 2017 (20170930 0730Z Day 3 shapefile | 20170930 0730Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170930 0730 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 101,787 5,862,837 Minneapolis, MN...St. Paul, MN...Sioux Falls, SD...Duluth, MN...Sioux City, IA...
Probabilistic Graphic
20170930 0730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 3 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 101,617 5,831,328 Minneapolis, MN...St. Paul, MN...Sioux Falls, SD...Duluth, MN...Sioux City, IA...
   SPC AC 300732

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0232 AM CDT Sat Sep 30 2017

   Valid 021200Z - 031200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF THE CENTRAL AND NORTHERN PLAINS VICINITY...

   ...SUMMARY...
   Risk for hail with stronger/locally severe storms is evident across
   portions of the central and northern Plains vicinity Monday.

   ...Synopsis...
   Additional amplification of the upper flow field over the U.S. --
   consisting of a trough over the West and a ridge in the East -- is
   expected this period, as short-wave energy continues digging
   south-southeast across California and the Great Basin, around the
   western fringe of the longer-wavelength trough.  At the surface, a
   southwest-to-northeast baroclinic zone across the central and
   northern Plains is forecast to make little progress, with background
   height rises aloft expected atop the region.

   ...Central and northern Plains vicinity...
   While afternoon destabilization is expected in the vicinity of the
   cold front across the central and northern Plains, a largely capped
   warm sector is expected to prevail, aided by background subsidence
   implied by the aforementioned height rises.  Most of the convection
   associated with the front will likely remain anafrontal, owing to
   weak ascent in a warm advection regime atop the boundary as provided
   by strong southerly low-level flow.  With shear sufficient for storm
   organization, a few stronger/severe cells will likely evolve. 
   However, with what appears to be a lack of surface-based pre-frontal
   convection, main severe risk appears likely to remain largely
   limited to hail with elevated storms, from afternoon onward.

   ..Goss.. 09/30/2017

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z