SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Sun Sep 19 2021 Valid 191630Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING AND TONIGHT OVER PARTS OF THE NORTHERN PLAINS... ...SUMMARY... Isolated severe thunderstorms are possible mainly across parts of the eastern Dakotas and northwest Minnesota late this afternoon into tonight. ...Northern Plains... An upper trough currently over WA/OR will amplify and move across the northern Rockies today - and into the northern Plains tonight. At the surface, a cold front will strengthen and move into the Dakotas/MN this evening and tonight, providing the focus for thunderstorm development. A few storms may form late this afternoon and early evening near the surface low over western SD. Other storms will form after dark from central MN into eastern SD - and eventually southward into NE. Low and deep layer wind fields will increase through the period as the upper trough approaches, resulting in a risk of locally gusty/damaging winds with the strongest cells. The main limiting factors for a more robust severe weather event include the rather warm temperatures in the 800-600mb layer effectively capping convective development until well after peak-heating, and marginal low-level moisture values. ...Southwest KS... Models continue to suggest a small area of concern for thunderstorms this afternoon from the Raton Mesa eastward into southwest KS. Forecast soundings in this area show a deeply mixed boundary layer with 50+ degree t/td spreads. The strongest showers and thunderstorms may produce dry microbursts capable of gusty winds, but limited low-level moisture and CAPE values generally below 500 J/kg suggest the risk of organized severe thunderstorms is rather low. ..Hart/Squitieri.. 09/19/2021 Read more LIVE: spc.noaa.gov
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