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Severe New Year's Week Severe Threat(s)

Looks like most of the action so far this afternoon has been the band of storms that is moving through west-central into northern Louisiana. Arkansas got pretty worked over by the earlier storms, but still saw there may have been 1 or 2 storms where a brief tornado touched down. Still a few storms further west in Oklahoma, but they seem to be falling apart as they move into the rain cooled air further east.
 
BufordWX said:
Looks like most of the action so far this afternoon has been the band of storms that is moving through west-central into northern Louisiana. Arkansas got pretty worked over by the earlier storms, but still saw there may have been 1 or 2 storms where a brief tornado touched down. Still a few storms further west in Oklahoma, but they seem to be falling apart as they move into the rain cooled air further east.
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Lots of junk convection competing with the storms today. This was one of the things that was mentioned as being able to possibly keep a lid on things. So far that has been the case outside of a few quick spinups.
 
Bham NOAA discussion:
Area Forecast Discussion
National Weather Service Birmingham AL
927 PM CST Mon Jan 2 2023

...New SHORT TERM...

.SHORT TERM...
(Tonight through Tuesday)
Issued at 925 PM CST MON JAN 2 2023

No big changes planned in the short term this evening. Plenty of
clouds, and a few showers popping up here and there. But the bulk
of the rain/storms remain to our west, to arrive here later
tonight. This is handled well with the current forecast.

/61/

Previous short-term discussion:
(This evening through Tuesday)
Issued at 139 PM CST MON JAN 2 2023

A low pressure system and trough will be developing over the plains
and moving towards the Great Lakes region while a frontal boundary
moves through this trough and approaches Alabama tomorrow through
Wednesday. Flow in the mid and upper levels will be predominately
from the south and southwest ahead of this front...with low level
flow from the southeast. Warm air and plenty of moisture will advect
into the state through the short term. This will allow for PW
values to approach an amount by tonight between the 90th
percentile and max for this time of year.

Today...scattered showers and thunderstorms will be possible through
the afternoon and early evening. Overnight...this activity should
weaken as the forcing from the day is lost and only scattered
showers with very isolated thunderstorms are expected.
Tomorrow...activity will be scattered through the early
morning...and increase in coverage and intensity through the late
morning and early afternoon. By overnight Tuesday...activity will be
mostly widespread with embedded supercells possible.

A mid level jet will move into the state tonight and remain through
Wednesday morning. Along with an upper level jet...this will allow
for plenty of directional and speed shear with 0-1km shear values
approaching 30-35 kts across the state through the early afternoon
Tuesday...dropping to about 20-25 kts towards evening. This jet will
remain strong through the early morning on Wednesday as it slowly
moves from west to east. This shear...along with very low LCL
heights with so much low level moisture...will be the main concern
for supercells and damaging winds.

An upper level jet will move across the southeast with divergence
and lift strong Tuesday afternoon and evening and again in the early
morning Wednesday.

Flooding is a potential mainly in any storms that train over the
same area. High PW values are going to allow any strong storms to
produce high rainfall rates quickly. And if any cells train...that
could lead to localized flooding concerns.

24
 
Gonna be a really tough forecast here. Looking over the WRF ARW and the Euro and it looks like we will have two distinct waves of severe weather, one tomorrow afternoon and evening and another overnight. The WRF really likes the afternoon with would probably be a moderate risk if it verifies across most of central AL. The Euro on the other hand likes the second as the first is cutoff by south AL convection. Both ARW and Euro increase cape to around 2000 in the over night hours across portions of central and southern AL which is absolutely absurd for January. On the other side, the NSSL WRF is very tame. I expect it is a the more wrong side, so I like a a middle ground between WRF with a tilt toward the ARW.

Bulk shear out of the WSW, broad based trough and the stronger forcing should be favorable for supercells. One thing I do see is on most of the models the flow from 850-500mb is relatively unidirectional. I’ve seen that issue lead to a more messy storm mode. The Euro continually showing the south AL convection early should also be considered.

I like the SPC map with a possible upgrade across a small part of AL around Montgomery.

Edit: Looking over the HRRR, the 0-3km cape being between 150-180 is also very concerning.
 
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What's going to be interesting is what/how effect the missed forecasts parameters play in today's storms.... The hi-res hodograph soundings for most of the model suites all appear to be between 5-10 degrees off from current temperatures. I don't have access to live dew points, but I can say it's undoubtedly muggy for early January in the A.M. If gulf convection doesn't initiate, this could be an interesting day for most of Alabama. Very interested to see how this plays out! Always been a rule of thumb here, if its 70 degrees, windy, and muggy in winter.... pay attention..guess we'll see if that holds true. Everyone stay safe today!
 
Hpdb301 said:
What's going to be interesting is what/how effect the missed forecasts parameters play in today's storms.... The hi-res hodograph soundings for most of the model suites all appear to be between 5-10 degrees off from current temperatures. I don't have access to live dew points, but I can say it's undoubtedly muggy for early January in the A.M. If gulf convection doesn't initiate, this could be an interesting day for most of Alabama. Very interested to see how this plays out! Always been a rule of thumb here, if its 70 degrees, windy, and muggy in winter.... pay attention..guess we'll see if that holds true. Everyone stay safe today!
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Same to a degree over here in N GA with many locations with temps near 60/low 60's and DP s very similar.. Even with dynamics moving off to the north, when I stepped outside air has "that feel" to it, CAD has mostly broken down a good bit earlier than progged, so need to be aware today/ this evening.
 
Screenshot 2023-01-03 050634.png

Area Forecast Discussion
National Weather Service Birmingham AL
356 AM CST Tue Jan 3 2023

...New SHORT TERM, LONG TERM, HYDROLOGY...

.SHORT TERM...
(Today through Wednesday)
Issued at 345 AM CST TUE JAN 3 2023

* Strong to severe thunderstorms likely across Central Alabama today
and tonight. All severe hazards are possible, in addition to
localized flash flooding.

A potent upper-level system is currently moving east across The
Plains this morning with a surface low set to move northeast across
the mid/upper Mississippi Valley today. Meanwhile, a warm sector
continues to establish across the Deep South as persistent southerly
low-level flow advects warm, moist air northward from the Gulf Coast
through the Ohio Valley. Dewpoints are already in the mid to upper
60s across portions of Central Alabama as of 3 AM this morning.

Throughout today, an ongoing mesoscale convective system will move
east across Tennessee and Mississippi, generally nearing our western
counties by late morning. Increasing temperatures ahead of this MCS
will foster 1,000-1,500 J/kg MLCAPE with modest 6-7 C/km mid-level
lapse rates. Enhanced mid- to upper-level flow will support eff.
bulk shear <55 kts. This parameter space will support organized
thunderstorms with a strongest updrafts becoming bowing segments or
supercells. These stronger storms will pose a threat of damaging
wind gusts, hail, and even a few tornadoes.

The evolution of convective activity still remains in question
today, and there are no correct answers regardless how long you
stare at model guidance. Wind shear, instability, and moisture will
be in place. The focusing mechanism (or lift) has been more
subtle/weak and harder to assess up to now. Primary synoptic support
aloft is progged to lift well to the north, and this is why
convection is forecast to outrun the cold front stalling to our
west. Most guidance also suggests veering 925-850 mb winds to occur
during this time (late afternoon & early evening), shrinking
hodograph curvature. However, kinematic/thermodynamic parameters are
sufficient to support severe weather threats as early as 11 AM in
the west, to 7 AM Wednesday morning in the southeast. And despite
shrinking hodographs, 100-300 m2/s2 0-1 km SRH is progged by most hi-
res guidance.

It appears more probable that we deal with two rounds of severe
weather. The first round should arrive late this morning into the
early afternoon as clusters of strong to severe thunderstorms move
into, or develop, in Central Alabama in association with initial
height falls. These storms appear to have the best access to quality
warm sector conditions into the mid to late afternoon, including
better 0-3 km CAPE, enhancing tornado potential south of I-20. Most
hi-res guidance suggests this convection will congeal into loosely
aggregated clusters or lines as they outrun the lagging cold front
in the late afternoon/early evening. This will cause slower
progression and/or training convection to occur in areas south of I-
20, leading to flash flooding potential. A second wave of strong to
severe thunderstorms will be possible later this evening as a
shortwave rotates around the closed upper low toward the Tennessee
Valley. This will provide better dynamics/support aloft,
accelerating the cold front eastward into Alabama with thunderstorms
focused along its axis. Any airmass recovery/lingering SBCAPE will
allow these storms to pose additional severe threats into Wednesday
morning. Severe threats will end as frontal passage occurs into
early Wednesday morning. Any flooding issues (from both rounds of
storms) may persist into late Wednesday morning.
 
That storm south west of Nashville looking like a problem. Had a hook on reflectivity for a short period.
 

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Getting the feeling this is what today will primarily consist of, short lived spin ups trying to get going. Hoping maybe they can't get the upper support they need to become to bad for a large swath with most of the upper level support pushing off quickly to the north?? Maybe? Maybe not? Like a powder keg fully loaded and someone holding A lighter just out of reach to set it off.
 
HRRR really appeared to copy and paste the evolution of yesterday. Multiple waves of storms of the same region the first wave gets going this afternoon over southern Alabama. This wave may be the most post potent. Like yesterday it conceals into a large mass with embedded supercell structures. It moves out and behind it you get another possible wave of discrete activity over northern Mississippi and Alabama ahead of the front. Behind that you would have a squall line right along the cold front. Could be a busy day.
 
Hpdb301 said:
Getting the feeling this is what today will primarily consist of, short lived spin ups trying to get going. Hoping maybe they can't get the upper support they need to become to bad for a large swath with most of the upper level support pushing off quickly to the north?? Maybe? Maybe not? Like a powder keg fully loaded and someone holding A lighter just out of reach to set it off.
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Yeah, I’m not counting on long trackers today. Tornadoes could be strong, but fairly short lived based on looking at the fairly unidirectional wind profiles and SSW winds at the surface.
 
12z HRRR is really robust with both rounds. Slowly shifting SE with the main threat, probably gonna come inline with the WRF and SPC.

Edit: actually on a quick glance at the 12z WRFs which have all come in hot. The threat area expands a lot more north. I’ll have to dive deeper later.
 

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Did something about this site change? It took me so long to find it. Anywho, I’m on the Tuscaloosa/Jefferson/Bibb county line but in Tuscaloosa county. It seems everything comes this way. Fingers crossed it doesn’t though. Spann said between 11ish am and 3am so I’m downing coffee and hanging out with you guys today. Good morning!
 
KellynaMoon said:
I don’t know how to post pictures yet but tornado watch out for all of west Alabama
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