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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.

Thursday, May 13, 2021

SPC May 13, 2021 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Thu May 13 2021 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF WESTERN/CENTRAL NEBRASKA AND NORTHWEST KANSAS... ...SUMMARY... Isolated large hail and damaging gusts will be possible this afternoon through late evening from western Nebraska into northwestern Kansas. ...

Synopsis... No changes to the ongoing forecast. Thunderstorms have begun to form in western Nebraska are expected to move southeastward this afternoon and evening. See MCD 605 for more details. ..Wendt.. 05/13/2021 .

PREV DISCUSSION... /ISSUED 1122 AM CDT Thu May 13 2021/ ...

Central High Plains this afternoon through late evening... A low-amplitude western ridge/eastern trough pattern will persist across the CONUS, with a belt of west-northwesterly mid-upper flow from the northern Rockies across the central Plains to the Southeast. Within this belt of stronger flow, an embedded shortwave trough over southern MT/northwestern WY will progress east-southeastward to NE by this evening/early tonight. Weak lee cyclogenesis is anticipated near the NE/WY border this afternoon/evening in advance of this midlevel trough, which will help to strengthen low-level southerly flow across NE/KS late this afternoon into early tonight. Low-level moisture is quite limited across the Great Plains this morning as a result of prior frontal passages, with regional 12z soundings and surface observations showing low-mid 40s boundary-layer dewpoints. Strong surface heating and some vertical mixing of the marginal moisture suggests that MLCAPE will likely be limited to around 500 J/kg. High-based thunderstorm development is expected later this afternoon/evening across western NE, along and immediately east of the lee cyclone/lee trough. Convection will subsequently spread south-southeastward across western/central NE toward northwestern KS later this evening into early tonight. Deep-layer vertical shear will favor supercells with some threat for marginally severe hail, while steep low-level lapse rates will favor strong outflow production as storms potentially grow upscale into a small cluster or two. An increase in low-level warm advection will help the convection persist into tonight, though the threat for severe storms will diminish. Read more LIVE:

NWS SPC Convective Outlook provided by

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