Jul 7, 2020 1630 UTC Day 1 Convective Outlook
Updated: Tue Jul 7 16:12:28 UTC 2020 (20200707 1630Z Day 1 shapefile | 20200707 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20200707 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 110,290 463,801 Bismarck, ND...Minot, ND...Mandan, ND...Dickinson, ND...Williston, ND...
SLIGHT 131,431 1,555,890 Billings, MT...Fargo, ND...Rapid City, SD...Great Falls, MT...Grand Forks, ND...
MARGINAL 160,222 8,917,174 Minneapolis, MN...St. Paul, MN...Madison, WI...Rockford, IL...Cedar Rapids, IA...
Probabilistic Tornado Graphic
20200707 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
5 % 57,418 99,018 Havre, MT...Miles City, MT...Lewistown, MT...Glendive, MT...
2 % 184,260 1,912,882 Billings, MT...Fargo, ND...Rapid City, SD...Bismarck, ND...Great Falls, MT...
Probabilistic Damaging Wind Graphic
20200707 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
SIG SEVERE 99,919 412,981 Bismarck, ND...Minot, ND...Mandan, ND...Dickinson, ND...Williston, ND...
30 % 110,176 463,976 Bismarck, ND...Minot, ND...Mandan, ND...Dickinson, ND...Williston, ND...
15 % 131,716 1,551,046 Billings, MT...Fargo, ND...Rapid City, SD...Great Falls, MT...Grand Forks, ND...
5 % 158,870 8,883,823 Minneapolis, MN...St. Paul, MN...Madison, WI...Rockford, IL...Cedar Rapids, IA...
Probabilistic Large Hail Graphic
20200707 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
SIG SEVERE 60,616 191,708 Great Falls, MT...Havre, MT...Miles City, MT...Lewistown, MT...Glendive, MT...
15 % 210,896 1,502,798 Billings, MT...Fargo, ND...Rapid City, SD...Bismarck, ND...Great Falls, MT...
5 % 121,191 1,957,081 Duluth, MN...St. Cloud, MN...Bozeman, MT...Butte, MT...Superior, WI...
   SPC AC 071612

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1112 AM CDT Tue Jul 07 2020

   Valid 071630Z - 081200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
   EASTERN MONTANA AND WESTERN/CENTRAL NORTH DAKOTA...

   ...SUMMARY...
   Severe storms capable of intense damaging winds, large hail and a
   few tornadoes are expected from central Montana eastward across the
   northern Plains and into Minnesota, today into tonight.

   ...Northern Plains...
   Water vapor imagery shows a strong upper trough moving across parts
   of ID/NV toward the northern Plains.  This system will begin
   affecting the mountains over western MT/WY by early afternoon with
   showers and thunderstorm development likely.  Storms will develop
   eastward into the adjacent high Plains of central MT by
   mid-afternoon, where backed low-level winds will maintain 50s
   dewpoints and MLCAPE over 2000 J/kg.  Strong deep-layer shear and
   veering winds with height will promote supercell storms capable of
   very large hail, damaging winds, and isolated tornadoes.  As the
   storms spread eastward this evening, activity should become more
   widespread.  Multiple convective clusters are expected, with an
   increasing risk of corridors of enhanced wind damage.  Activity is
   expected to persist much of the night, tracking across ND and into
   northern MN by Wednesday morning.

   ...Western SD into NE/CO/NM...
   Scattered afternoon thunderstorms are expected to form along the
   instability axis from the Black Hills region southward into parts
   the NE panhandle, eastern CO and northeast NM.  Shear profiles on
   the northern end of this corridor will be sufficient for a few
   severe storms capable of hail and damaging winds.  However, weak
   flow aloft, warm mid-level temperatures, and lack of upper forcing
   suggest that the severe threat over the remainder of the area will
   be very isolated and chaotic.

   ..Hart/Squitieri.. 07/07/2020

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