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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.

Sunday, May 29, 2022

SPC May 29, 2022 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Sun May 29 2022 Valid 292000Z - 301200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT FROM NORTHEAST NE INTO CENTRAL MN... ...SUMMARY... Severe thunderstorm gusts of 60 to 85 mph, hail to near baseball size, and a few tornadoes are possible this afternoon and tonight from parts of Nebraska northeastward into southwestern and central Minnesota. Storms have developed across the central Rockies (see MCD 961), but much of the warm sector across the Plains remains capped. Observations and the latest runs from the HRRR suggest it may be another hour or two before convection develops in this region. However, an enhanced risk remains appropriate and in the correct location with no adjustments necessary. Expanded the thunder line to include northern Michigan ahead of the elevated storms across eastern Wisconsin which continue east. ..Bentley.. 05/29/2022 .PREV DISCUSSION... /ISSUED 1124 AM CDT Sun May 29 2022/ ...NE to MN this afternoon through tonight... In the wake of a lead shortwave trough, a surface cold front has progressed southward into southeast CO/northwest KS/central NE. This boundary is expected to stall today, in response to renewed lee cyclogenesis in the vicinity of southeast CO/western KS, downstream from the deep midlevel trough moving eastward from the Great Basin. The lee cyclogenesis will maintain strong southerly low-level flow across KS/OK and northward transport of mid 60s boundary-layer dewpoints into the stalling frontal zone across NE. Farther northeast, the warm sector will be maintained today into MN, in the wake of morning convection. Additional storm development will be possible this afternoon along the stalled front and near the remnant initial surface cyclone, from northwest MN southward into eastern SD. Where storm development is more probable, moderate-strong buoyancy is expected in pockets of stronger surface heating across western MN. Deep-layer vertical shear will be sufficient for supercells, though there are some weaknesses in forecast hodograph structures across this area this afternoon/evening. Large hail, damaging gusts, and a couple of tornadoes will be possible. The more substantial severe threat should evolve this evening starting across NE, and continue overnight across southeast SD, northwest IA, and southwest MN. Two potential convective modes are evident: 1) isolated supercell development this evening/early tonight along the stalled front in the vicinity of northeast NE, and 2) cluster/supercell evolution of initially post-frontal convection across CO/WY this afternoon into NE this evening. Any isolated supercell development this evening will be focused along the stalled front in NE, with the potential for very large hail (baseball size or larger) and a few tornadoes. The ongoing convection over northwest CO will likely spread eastward in the zone of ascent preceding the primary shortwave trough over the Great Basin. Storms in this zone will pose a marginal wind/hail threat this afternoon across northern CO/southern WY, with storm intensification more probable by late afternoon/evening as the convection/forcing for ascent encounter richer moisture/larger buoyancy across western/central NE (along and to the immediate cool side of the front). There will be the potential for both upscale growth of clusters and embedded supercells, with the potential to produce a few tornadoes, very large hail, and swaths of 60-85 mph outflow winds tonight. Read more CHECK UPDATE ZOOM GRAPHIC