Subj : DAY2SVR: Nws Storm Predic To : All From : Mike Powell Date : Thu Sep 11 2025 08:48:34 ACUS02 KWNS 110557 SWODY2 SPC AC 110555 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE FOUR CORNERS... ....SUMMARY... Strong to severe storms capable of isolated severe wind gusts are possible across the Four Corners region on Friday. Additional storms are possible over the northern Plains and Upper Midwest Friday. ....Northern Plains and Upper Midwest... A shortwave trough and enhanced southwesterly flow will move out of the northern Rockies and into the northern Plains Friday as upper ridging begins to move eastward. Associated with the approaching trough, a weak lee cyclone along a stalled front over the Dakotas will draw rich low-level moisture westward toward a second weak cold front moving out of the Rockies. Modest ascent is expected much of the day along and north of the surface low/front across northern WY, western ND and central/eastern MT. While cloud cover and early morning convection may temper heating somewhat, elevated buoyancy is expected to support scattered to numerous storms through the afternoon. With 35-45 kt of southwesterly flow aloft extending mid and upper-level hodographs, a few elevated clusters or supercells are possible. Steep mid-level lapse rates and favorable deep-layer shear could support isolated hail and strong gusts with the strongest storms, though confidence in the overall severe risk remains fairly low given the potential for clouds and early morning storms. Convective coverage may increase through the evening and overnight hours as a 35-45 kt southerly low-level jet develops over the Plains. CAM guidance remains quite dispersive, but some solutions show the potential for isolated severe gusts with elevated storm clusters moving eastward across the Dakotas overnight. A second cluster of elevated storms may be ongoing at the beginning of the period across the eastern Dakotas/western MN associated with a weak shortwave trough and low-level warm advection along the stalled front. If this occurs, a low-end wind/hail threat could exist during the morning as the shortwave continues east/southeastward toward the Great Lakes. Buoyancy and ascent should decrease quickly with eastward extent suggesting only a limited severe risk. ....Four Corners... A shortwave trough and an associated belt of stronger southwesterly flow aloft will be present over portions of the eastern Great Basin and central Rockies Friday. An associated cold front will also shift eastward, impinging upon a modified monsoon air mass across northern AZ/NM into eastern UT and western/central CO. A band of showers and possibly a few thunderstorms are likely be ongoing early in the period ahead of the front. While moisture content (PWATS 0.5-0.8 inches) will not be overly robust, it should be sufficient to support weak diurnal destabilization amid cloud cover and remnant showers/storms. Convection should gradually increase in coverage along the front and across the higher terrain by late morning and early afternoon. The stronger mid-level flow could allow for a few storms to organize into mutlicell clusters or weak supercells. With steep low and mid-level lapse rates present, strong gusts appear possible with any sustained storms, along with small hail. ...Lyons.. 09/11/2025 $$ --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1) .