Jun 30, 2020 1630 UTC Day 1 Convective Outlook
Updated: Tue Jun 30 16:03:12 UTC 2020 (20200630 1630Z Day 1 shapefile | 20200630 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20200630 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 125,800 2,420,887 Sioux Falls, SD...Fargo, ND...Sioux City, IA...Bismarck, ND...Grand Island, NE...
MARGINAL 294,662 26,118,676 Charlotte, NC...Nashville, TN...Atlanta, GA...Omaha, NE...Lincoln, NE...
Probabilistic Tornado Graphic
20200630 1630 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 81,814 926,441 Sioux Falls, SD...Bismarck, ND...Minot, ND...Norfolk, NE...Aberdeen, SD...
Probabilistic Damaging Wind Graphic
20200630 1630 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 125,144 2,325,678 Sioux Falls, SD...Fargo, ND...Sioux City, IA...Bismarck, ND...Grand Island, NE...
5 % 294,639 26,085,720 Charlotte, NC...Nashville, TN...Atlanta, GA...Omaha, NE...Lincoln, NE...
Probabilistic Large Hail Graphic
20200630 1630 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 104,461 1,540,909 Sioux Falls, SD...Sioux City, IA...Bismarck, ND...Grand Island, NE...Minot, ND...
5 % 126,562 2,639,456 Omaha, NE...Lincoln, NE...Abilene, TX...Wichita Falls, TX...Fargo, ND...
   SPC AC 301603

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1103 AM CDT Tue Jun 30 2020

   Valid 301630Z - 011200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
   THE CENTRAL AND NORTHERN PLAINS...

   ...SUMMARY...
   Thunderstorms with damaging winds and hail are possible this
   afternoon through tonight across parts of eastern Nebraska, the
   Dakotas and western Minnesota/Iowa.

   ...Northern Plains...
   A persistent upper low remains centered over ID today, with
   moderately strong and deep southerly flow across the
   central/northern Rockies and northern Plains.  A large cluster of
   thunderstorms has been affecting western ND this morning, providing
   abundant clouds/precipitation, and limiting heating/destabilization
   across the region.  There is limited confidence whether this area
   can recover from morning storms and pose an afternoon/evening threat
   of severe storms.  Will maintain the ongoing SLGT risk, but portions
   of western/central ND may be removed in later outlooks.

   Farther south, strong heating will lead to a very unstable air mass
   across portions of southeast ND/SD/NE, with forecast soundings
   showing MLCAPE values of 3500-5000 J/kg.  A shortwave trough
   currently rotating around the base of the low across WY/CO will
   approach the corridor of strong CAPE by late afternoon, resulting in
   rather widespread thunderstorm development.  Initial storms may be
   supercellular, but it appears activity will rapidly evolve into
   multiple linear structures capable of damaging winds and some hail. 
   These storms will likely persist through much of the night as they
   spread eastward into parts of western MN/IA.

   ...TX...
   Similar to yesterday, hot surface temperatures exceeding 100F are
   expected along the dryline that will extend from the San Angelo area
   into southwest OK.  East of the dryline, near dry-adiabatic low/mid
   level lapse rates and dewpoints near 70F will yield extreme CAPE
   values.  Forcing is weak.  But thermal circulations along the
   dryline may result in isolated thunderstorms for a few hours late
   this afternoon and early evening.  Those storms that form may
   produce locally damaging wind gusts and hail.

   ...Mid MS Valley...
   Water vapor imagery shows a remnant MCV north of St Louis.  There is
   a corridor to the south of the MCV from southeast MO into western
   KY/TN where strong heating and significant destabilization is
   occurring.  This area is likely to see scattered thunderstorm
   development this afternoon.  Vertical shear is weak, suggesting
   activity will be chaotic and weakly organized.  But large CAPE
   values and steep low-level lapse rates will support a risk of
   locally gusty/damaging winds.

   ..Hart/Wendt.. 06/30/2020

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