Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0246 AM CST Sat Dec 13 2025 Valid 161200Z - 211200Z ...DISCUSSION... Moisture return will begin on Tuesday/D4 across Texas with some weak instability and thunderstorm potential arriving by Wednesday/D5. Significant differences in the upper-level pattern begin on Thursday/D6 and beyond which will significantly impact thunderstorm and severe weather potential. The ECMWF and AIFS have a sharper mid-level trough farther south on Thursday/D6. This will result in a stronger cold front and farther north moisture return ahead of the front. In addition, some weak instability may develop beneath the stronger mid-level jet. This may create an environment favorable for a few stronger storms from the Lower Ohio Valley to the Mid-Mississippi Valley. This stronger scenario would likely push a strong cold front deep into the Gulf on Friday and limit thunderstorm potential into the weekend. A less amplified solution (as shown by the GFS and AIGFS) would not support much of any strong storm threat on Thursday/D6. However, it would keep low to mid 60s dewpoints across Texas and the Lower MS Valley on Friday and into the weekend. This may result in weak to potentially moderate instability across portions of the southern Plains and possibly into the Mid-Mississippi Valley through the weekend. Despite this lingering instability, a mostly zonal mid-level pattern would not support a significant severe weather threat. Overall, severe weather potential remains somewhat low for much of the period. Some low-end severe weather threat may exist from Thursday/D6 and beyond as low-level moisture increases, but significant uncertainties in the evolution of the upper-level pattern make any forecast for time or location of any potential low-end threat difficult.Read more
