Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Fri Dec 25 2020 Valid 281200Z - 021200Z ...DISCUSSION... ...Monday/Day 4 and Tuesday/Day 5... The medium range models move an upper-level trough across southern California on Monday and across the Desert Southwest Monday night. The system is forecast to strengthen on Tuesday, moving quickly eastward across the Rockies and into the Great Plains. Thunderstorm development will be possible Tuesday afternoon and evening in parts of the Great Plains and mid Missouri Valley, ahead of the trough and to the west of a strengthening low-level jet. At this time, the greatest chance for thunderstorms is forecast from eastern Kansas southward into north-central Texas. Due to weak moisture return ahead of the system, instability is expected to be too low for a substantial severe threat. However, due to uncertainties, will maintain "predictability too low" at this time. ...Wednesday/Day 6 to Friday/Day 8... The upper-level system is forecast to progress eastward from the Great Plains Tuesday night into the Mississippi Valley by Wednesday night and to near the East Coast by Friday. Thunderstorms will be possible each day ahead of the trough and just ahead of an associated cold front. The potential for thunderstorm development should progress eastward from the central Gulf Coast on Wednesday to the Carolinas and Florida on Thursday. Surface dewpoints are forecast to reach the 60s F across southern Louisiana, southern Mississippi and southern Alabama on Wednesday and across Florida, Georgia and parts of the Carolinas on Thursday. A severe threat will be possible ahead of the front in the moist airmass if instability can increase enough. However, uncertainty exists concerning the timing of the upper-level trough and instability. For this reason, will maintain "predictability too low" in the mid to late week timeframe.
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