SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 AM CST Wed Dec 17 2025 Valid 171300Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHWEST AND NORTHERN INTERMOUNTAIN REGION... ...SUMMARY... Sporadic severe wind gusts may accompany low-topped convection across parts of the Northwest and northern Intermountain region this morning into midday. ...Northwest/Northern Intermountain region... A progressive/vigorous shortwave trough will continue to modestly amplify and otherwise race east-southeastward from the Washington/British Columbia border vicinity this morning to the northern Plains tonight. Intense deep-tropospheric flow (highlighted by 55-85 kt at 700 mb) will accompany this wave, yielding widespread high winds across much of the Northwest to the northern Great Plains. Low-topped convection, occasionally capable of lightning and semi-organized line segments, will continue in association with the east/southeastward-advancing cold front, with convection potentially expanding by late morning towards the Snake River Plain/Yellowstone vicinity and potentially other parts of the northeast Great Basin by afternoon. Surface-based instability will be very limited, but some convectively enhanced wind gusts may occur. ..Guyer/Lyons.. 12/17/2025
