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 %
55,824
93,479
Havre, MT...Miles City, MT...Lewistown, MT...Glendive, MT...
2 %
166,561
1,598,752
Billings, MT...Fargo, ND...Rapid City, SD...Bismarck, ND...Great Falls, MT...
Probabilistic Damaging Wind 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
64,745
137,648
Havre, MT...Miles City, MT...Lewistown, MT...Glendive, MT...Sidney, MT...
30 %
91,663
218,119
Dickinson, ND...Williston, ND...Havre, MT...Miles City, MT...Lewistown, MT...
15 %
150,670
1,776,103
Billings, MT...Fargo, ND...Bismarck, ND...Great Falls, MT...Grand Forks, ND...
SPC AC 070528
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1228 AM CDT Tue Jul 07 2020
Valid 071200Z - 081200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF MONTANA INTO THE WESTERN DAKOTAS...
...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 Tuesday afternoon into the
nighttime hours.
...Montana to Minnesota...
Seasonally strong 12hr mid-level height falls (60-90m) will spread
across the northern Rockies later today ahead of a strong negatively
tilted short-wave trough. Latest model guidance suggests this
feature will approach the ID/MT border by 18z, MT/ND border by
08/06z, then into southern MB by sunrise Wednesday morning.
Favorable diffluent flow aloft, for storm-top venting, and a 60kt
500mb speed max, suggest thunderstorms should develop rather early
in the period. Forecast soundings favor convection organizing
quickly along a sharp cold front across western MT, possibly by 18z.
Wind profiles are quite strong and are more than adequate for
sustaining organized rotating updrafts. As a result, early in the
convective cycle, isolated supercells will likely be observed.
MLCAPE in excess of 2000 J/kg is expected across central MT into the
western Dakotas by mid afternoon as temperatures warm ahead of the
front.
Given the strong large-scale forcing for ascent, surging frontal
zone, and ample buoyancy, it appears convection should grow upscale
quickly along the wind shift. Late-evening CAMs support this
scenario with a pronounced squall line expected to mature and surge
across eastern MT by early evening. Large hail and a tornado threat
will be more common with supercell structures. Once the predominant
storm mode becomes a linear MCS, severe threat will transition to
damaging winds -- possibly with gusts in excess of 65kt in places.
Severe threat will progress across the northern Plains, ahead of the
aforementioned short wave, during the overnight hours.
..Darrow/Moore.. 07/07/2020
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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