Severe Weather Threat on 12/31/2020 through 1/1/2021??

[kayman]

Two days of distinct wording in the forecast referring to an overnight tornado and damaging wind threat across parts of AL and GA due to strong low-level shear. Then redevelopment of storms over N GA, and movement into SC and NC associated with the warm sector of this system. Once again tornado and damaging winds are the main threats due to strong low-level shear over N, E, and NE GA along with SC, and the Southern portion of NC around Metro Charlotte.

 

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SPC AC 290820 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 AM CST Tue Dec 29 2020 Valid 311200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM FAR SOUTHEAST TEXAS INTO THE CENTRAL GULF COAST STATES... ...SUMMARY... Severe thunderstorms associated with a tornado threat and wind damage will be possible Thursday into Thursday night from far southeast Texas into the lower Mississippi Valley and across the central Gulf Coast States. ...Southeast Texas/Lower Mississippi Valley/Central Gulf Coast States... An upper-level low will move from northern Mexico into the southern Plains on Thursday. Divergent flow aloft will overspread eastern Texas and Louisiana as the negatively-tilted system deepens. A large cluster of thunderstorms appears likely to be ongoing in southeast Texas at the start of the period. This convection is forecast to move eastward as a low deepens and moves northeastward into the Arklatex. Although instability will be weak along the attendant surface trough, strong deep-layer shear will create conditions favorable for severe storms. Lift associated with a mid-level jet, rounding the base of the upper-level system, will provide additional support for organized storms. As the mid-level jet moves eastward across the Lower Mississippi Valley on Thursday, thunderstorm development is expected to occur across parts of Louisiana and Mississippi. Instability is forecast to gradually increase across the moist sector, which should be located from Louisiana to southwestern Alabama. Discrete thunderstorms that develop ahead of the cold front across the moist sector could have a wind damage and tornado potential. During the late afternoon, the most favorable area would be in far southeast Louisiana, where the models maximize instability at the northern end of the moist axis. The corridor of maximized low-level moisture is forecast to shift eastward across southern Mississippi and southern Alabama during the evening and overnight period. Models suggest the possibility of a convective line located along the moist axis. This line would be associated with a continued wind damage and tornado threat during the overnight period. ..Broyles.. 12/29/2020

 

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ZCZC

PCSWOD48 ALL ACUS48 KWNS 290955 SPC AC 290955 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0355 AM CST Tue Dec 29 2020 Valid 011200Z - 061200Z ...DISCUSSION... ...Friday/Day 4 and Saturday/Day 5... An upper-level trough is forecast to move northeastward across the mid Mississippi Valley on Friday as southwest mid-level flow remains in place along the Eastern Seaboard. The moist sector should be located across much of Georgia and South Carolina. Thunderstorms may develop in Georgia Friday afternoon ahead of the upper-level trough with this convection spreading east-northeastward across South Carolina and into southern North Carolina. Due to strong low-level shear, a tornado threat could exist with this activity, in addition to having a wind damage potential.

[nrgjeff]

Dixie Holiday Special is coming up. I like the Day 3. System has really slowed down. It'll be a Louisiana and South Mississippi problem, perhaps overnight. Storms should get going in eastern Texas and enter southern Alabama by the end of the period. LLJ will increase with time Thursday night. Oh goodie for LA/MS. 

Friday Day 4 looks to refire or be ongoing in Georgia and the Carolinas. Could start in the southern Appalachians, before ramping up in the afternoon and lower elevations east. Piedmont gets involved. SPC rightly ends the action before the Low Country as upper dynamics will be ejecting away. However the LLJ hangs in through Friday afternoon.

None of this is chase worthy imo. However it'll make nice armchair entertainment during commercial breaks of football games.

[nrgjeff]

I'll leave Thursday to the SPC. I agree with them; and, it's way to far for me to even consider chasing. Overnight LA/MS is kind of a punt too.

Friday forecast has shifted south and east. Looks like a cool wedge coming in from the Carolinas into North Georgia. At the same time, low level flow may hold up more than previous forecast out to the SC Coast and for southeast NC. Atlanta is on the north edge of Marginal, with very conditional instability. 

Best chance of instability is South Carolina below Columbia. That's way out of my range for a daytrip. Macon to Albany, Georgia is another possibility with some breaks in the trees. However construction on I-75 south of ATL makes it a hard pass. That construction is sooo annoying!

New Year's looks like watching football and during commercial breaks, severe wx from my nice warm living room.