• Welcome to TalkWeather!
    We see you lurking around TalkWeather! Take the extra step and join us today to view attachments, see less ads and maybe even join the discussion.
    CLICK TO JOIN TALKWEATHER

Severe WX Severe Weather Threat January 23-25, 2023

UncleJuJu98 said:
Looks like the line breaks and supercells for a brief time fire and have there own space in the small warm sector.
Click to expand...

I still think that just because a line maybe the most dominant storm mode, doesn't mean QLCS and possibly embedded supercell tornadoes will be a possibility - especially with such strong wind fields. Yes there might not be discrete supercells with violent tornadoes, but after dark hard to warn spin ups can be strong and in some cases have been intense. That's why I am not resting easy just yet as I think we will pretty likely have a dangerous severe weather event come Tuesday, whether its supercells or QLCS tornadoes.
 
What's the chance of a prolific tornado event for the Florida panhandle and Alabama coast can anybody chime in? Seems like a good possibility atleast with hi res runs of storms forming over the panhandle along the southern border of the warm front?
 
I'll go ahead and say it both WRF and long range HRRR show and support it. There's a possibility for a violent tornado or two along the coastal regions. Don't give me flak for this lol.. but the WRF at it's last frame almost remind me of the situation with the Lee county storm.
 
And there's the risk upgrade:
RadarSPC.jpg

RadarSPC TOR.jpg
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TUESDAY EVENING
INTO TUESDAY NIGHT ACROSS SOUTHEASTERN LOUISIANA AND
MISSISSIPPI...SOUTHWESTERN ALABAMA AND THE WESTERN FLORIDA
PANHANDLE...

...SUMMARY...
Severe thunderstorms are possible near mid to upper Texas coastal
areas Tuesday afternoon, before spreading into parts of southeastern
Louisiana and Mississippi through southwestern Alabama and the
western Florida Panhandle Tuesday night. These storms will be
accompanied by a risk for potentially damaging wind gusts and
tornadoes, a few of which could be strong.

...Synopsis...
An initially prominent mid-level high over the southern mid-latitude
Pacific likely will weaken, with a new high center gradually
beginning to form in higher latitudes, within persistent
larger-scale ridging. This ridging is forecast to continue to build
north-northeastward across British Columbia, Yukon and parts of the
Northwest Territories Tuesday through Tuesday night, with amplified
large-scale troughing being maintained downstream, along and east of
the Rockies Mountains. The most prominent perturbation within this
regime, initially a vigorous short wave trough with a compact,
embedded deep mid-level low, is still forecast to accelerate out of
the base of the troughing by early Tuesday.

The NCEP SREF remains notably slower than most other model output,
which generally indicates that the perturbation will rapidly
progress across the southern Great Plains into the Mid South by late
Tuesday night, accompanied by significant surface cyclogenesis near
mid/upper Texas coastal areas into the lower Mississippi Valley,
then north-northeastward into the Mid South. As this occurs, an
intense west-southwesterly mid/upper jet (including 90-100 kt around
500 mb) is forecast to develop across the lower Mississippi through
Tennessee Valleys by 12Z Wednesday. In association with the
developing cyclone, a southerly low-level jet may include speeds
increasing to 50-70 kt, and perhaps even stronger to the east of the
lower Mississippi Valley during a period of more rapid deepening
Tuesday evening.

...Southeast Texas coastal through central Gulf Coast states...
With little appreciable change to model forecasts concerning the
synoptic forcing, the presence of an initially cool/stable
boundary layer across much of the Gulf Coast region remains the
primary potential limiting factor to the development of a more
substantive risk for severe thunderstorms Tuesday through Tuesday
night. The boundary layer across much of the northern Gulf of
Mexico will also still be in the process of modifying from prior
frontal intrusions, but it does appear that mid/upper 60s F surface
dew points will rapidly advect toward northwestern through north
central Gulf coastal areas, and perhaps at least a bit inland.

Near-surface destabilization across and inland of mid into
upper Texas coastal areas will contribute to an environment
conducive to organizing convective development, including supercells
Tuesday afternoon. Thereafter, similar destabilization in a
corridor across southeastern Louisiana into southwestern
Alabama still seems probable Tuesday evening through Tuesday night.

Beneath a plume of modestly steepening lapse rates, this is expected
to contribute to a corridor of destabilization sufficient to
maintain an organized convective cluster or line, with embedded
supercells, along an eastward advancing pre-cold frontal confluence
zone. Aided by low-level warm advection in advance of this
activity, this may be preceded by a few discrete supercells.

It is still possible that a residual layer of moist adiabatic to
more stable near-surface lapse rates within the warm sector could
tend to minimize the number of potentially severe storms. However,
the latest (23/03Z) forecast soundings from the Rapid Refresh, which
extend out through 06Z Tuesday night, increase confidence for at
least weak surface-based destabilization to occur in a corridor
across southeastern Louisiana into southwestern Alabama/western
Florida Panhandle. With low-level hodographs forecast to become
very large and clockwise curved, in the presence of strong
deep-layer shear, the environment may become supportive of a couple
strong tornadoes in the supercell storms.
Click to expand...
 
Nws of mobile says there's a incredibly high ceiling In terms of tornadoes and damaging wind for the coastal regions, I'd imagine more upgrades are on the horizon depending on the evolution of models.

Could be a prolific coastal tornado event.
 
Synopsis...The aforementioned potent upper trough will begin its
march northeast across the Tennessee Valley Tuesday night and
lift northeast into Ohio by daybreak Monday morning. The
associated surface low developing over eastern Texas will lift
northeast across Louisiana and into northwestern Mississippi as
it continues to strengthen. An associated cold front will surge
quickly eastward across the northern Gulf Coast as a warm front
attempts to surge northward with the surface low. The progression
of the warm front will play a big role on the potential for severe
weather but more on that in the Severe section. Isolated to
scattered showers and thunderstorms will be possible with the
northward progressing warm front during the early evening hours
Tuesday night. However, the main show will arrive with the cold
front and prefrontal surface trough/convergence zone. A likely
line of strong to severe storms will have already developed
Tuesday afternoon along the surface trough/front and will be
barreling eastward likely reaching our southeastern Mississippi
counties before midnight. This line will be going nascar speeds as
it races across our area likely reaching I-65 around midnight and
departs the western Florida Panhandle sometime around or before
sunrise Wednesday. This line will bring the potential for strong
to severe storms with damaging wind gusts and tornadoes.

Severe...The severe threat is a rather tricky one as the ceiling
for this event could be quite high, but the floor could be quite
low. Really seeing three scenarios at this point that range from
rather significant to potentially not much at all and all three
are on the table at this point. With that said, the overall
environment is potent at least in the shear category. As the upper
trough strengthens a incredibly potent low level jet will develop
across the southeast with 850 mb winds in the 65 to 75 knot range
which is beyond bonkers. For reference, maybe only seen that once
in the last 4 years and with a nearly 100 to 110 knot 500 mb jet
moving overhead shear will not be an issue. The hodographs being
portrayed are almost comical with incredibly long-curved
hodographs with bulk shear in excess of 60 knots and 0-1km SRH 400
to 500 m2/s2. From a shear standpoint you really cannot get more
ripe for organized storms with high end damaging wind and stronger
tornado potential. The issue is the instability and it will be
lacking. Given our rather recent frontal passage and short return
flow period, rich Gulf moisture will be struggling to surge
northward at the last second. This will likely lead to marginal
instability maybe topping out at 1000 J/KG at best as mid-level
lapse rates attempt to steepen and better moisture surges in.
Along with the rather paltry instability, the upper forcing will
begin to move out of the area leading to less lift especially as
we move east of I-65 and approach the Florida Panhandle. This will
also complicate things as the combination of limited instability
and limited forcing usually does not mix well with insane shear
leading to storms struggling due to over-shearing. So there seems
to be three likely scenarios on the table.

1. The first is the line moving in from the west remains intact as
it progresses across the area as supercells form out ahead of the
line. This is probably worst case scenario likely leading to a
rather significant severe weather outbreak. This would be the
combination of slightly better lift and the higher end of
instability occurring. In this scenario a rather potent QLCS will
likely bring widespread damaging winds and several embedded
tornadoes for most of the area. Any supercells that would develop
ahead of the line would be capable of strong tornadoes given the
higher end environment. The main thing to watch the next 48 hours
will be the trend in instability. If model guidance trends upwards
then this scenario will be more likely. Right now confidence in
this is low probably around 20% chance of this happening.

2. The second scenario is the line approaches southeastern
Mississippi and then begins to slowly break apart as it moves
across our area. As the forcing lifts north, storms might become
more shear dominant leaving their cold pool in the dust as the
line breaks down into more semi-discrete cells. Given the shear
environment a couple of these cells would likely evolve into
supercells capable of tornadoes with a few strong tornadoes
possible. The question will be if there will be enough instability
to support the higher shear without the help of stronger forcing.
The best chance for that higher instability would be across the
Florida Panhandle so we would likely see a line of storms across
southeastern Mississippi capable of damaging winds and tornadoes
quickly turn into cells as it moves towards I-65 and the threat
move towards the northwestern Florida Panhandle with predominantly
a tornado threat. Confidence in this scenario is probably medium
around 50% but still a lot riding on it.

3. The final scenario would be the Forecasted Convective Amplification Deficiency. In this scenario the
instability just never really gets rich enough to support the
insane environment and the better lift lifts off to the north. In
this scenario the storms would be overpowered by the shear and
just fall apart leading to a broken line of showers across the
area. Sometimes the environment can be too hostile and with the
shear values in place this certainly could be possible. Imagine
the head of the storms moving so fast they detach from the legs
because the legs can`t keep up. Confidence in this is low around
30% but the floor is possible.

With all that said, the environment is there and very little
changes to the instability and lift could lead to significant
results. Given the incredibly high ceiling and still a solid
potential of some significant severe weather occurring across the
area the SPC has upgraded most of the area to an Enhanced risk
for severe weather.

High Winds....As the upper trough continue to strengthen and move
closer to the area, one of the more impressive low level jets I
have seen for this area will overspread. 65 to 75 knots at 850 mb
and well over 55 knots at 950 mb will provide a rather potent
reservoir of strong winds to mix down. As the aforementioned warm
sector moves north, these winds will be increasingly likely to mix
to the surface likely resulting in widespread areas of sustained
winds approaching 40 mph with local gusts in the 50 to 60 mph
range. Given recent rains and the potential for rain to be
occurring during this period, the potential for numerous trees to
come down across the area will be there. With trees comes
powerlines and power loss. Given the nocturnal nature of this
system and the higher potential for powerloss before the
approaching severe weather, it is critical that you have MULTIPLE
ways to receive warnings that will wake you up. Ensure that at
least two ways are battery powered and the batteries are charged
including phones and weather radios. A Wind advisory will be
needed and the potential for a high wind warning is certainly
there.
 
You must log in or register to reply here.
Back
Top