SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0642 AM CST Mon Dec 23 2024 Valid 231300Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast through tonight across the contiguous United States. ...Synopsis... Water-vapor imagery this morning shows a mid-level trough over AZ moving east and a northern stream trough over the Pacific Northwest. The northern mid-level trough will latitudinally expand southward into the central Rockies/south-central High Plains as a ridge amplifies over the Interior West in its wake. As this occurs, a partial phasing of mid-level trough over the Desert Southwest will occur as it moves into the southern High Plains. Farther west, a powerful upper trough will reach the WA/OR/northern CA coasts late tonight. In the low levels, surface high pressure will influence conditions over much of the Lower 48 states. Weak/ill-defined lower pressure over central TX will facilitate southerly flow from the TX coastal plain northward into the Red River Valley. Weak 850-mb warm-air advection will likely persist through the period across north TX into OK while a modest increase in moisture eventually results in weak elevated instability. Isolated to widely scattered showers and a few thunderstorms are possible tonight over eastern OK and perhaps as far south as north TX. ..Smith/Goss.. 12/23/2024