SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CST Wed Dec 31 2025 Valid 021200Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... General thunderstorms are forecast, mainly Friday night into early morning Saturday, across the central Gulf Coast and Deep South, as well as along a portion of the Pacific Coast. ...Central Gulf Coast and Deep South... At least isolated thunderstorm potential should return across a portion of the interior Deep South on Friday night. Meager elevated buoyancy should develop as low-level moistening occurs ahead of a leading shortwave impulse tracking across the Mid-South to TN Valley. This impulse may dampen downstream of a shortwave trough progressing from the Four Corners to north TX. The bulk of MUCAPE should largely remain at around 500 J/kg or less, owing to modest mid-level lapse rates. Farther south towards the central Gulf Coast from southeast LA to the FL Panhandle, richer low-level moisture should spread somewhat inland ahead of the more prominent shortwave trough. Most convective-parameterized models suggest an increase in convective development may occur at the end of the period within the low-level theta-e gradient. Despite a generally zonal deep-layer wind profile, adequate low-level hodograph curvature and robust speed shear renders a conditional supercell concern. But poor mid-level lapse rates renders concern for the degree of convective development prior to 12Z, with the 00Z RRFS having minimal deep convective signal. With minimal ML probabilities across this area as well, will defer to later outlook cycles for a level 1-MRGL risk highlight. ...Coastal northern CA and southwest OR... A large-scale upper trough will approach the Pacific Coast, with an intense mid-level jetlet likely impinging on the northern CA coast on Friday night. Fast deep-layer flow is anticipated within the low-level warm conveyor, but should remain entirely meridional until near the end of the period. Instability within the warm conveyor appears minimal, suggesting that thunderstorm potential will remain negligible amid strong gradient flow. Steepening mid-level lapse rates may brush the northern CA to southwest OR coast in the early morning Saturday. This should support scant buoyancy and potential for very isolated thunderstorms. ..Grams.. 12/31/2025
