Severe Weather risk 5/03/17

[weatherextreme]

With some interest popping up around this sub-forum I decided to start up this thread for the an enhanced threat for this coming Wednesday.

 

 

 

 

...SUMMARY...
   Strong to severe thunderstorms will be possible from central/eastern
   Texas to the central Gulf Coast Wednesday into Wednesday night.  A
   potential will exist for damaging wind gusts, isolated large hail
   and a few tornadoes.

   ...East Texas/Louisiana/Southern Arkansas/Mississippi...
   A positively-tilted upper-level trough is forecast to dig south
   southeastward into the southern Plains on Wednesday as a 70 to 80 kt
   mid-level jet moves into the base of the trough. At the surface, a
   cold front is forecast to move southeastward across the southern
   Plains as a warm front sets up from the Arklatex east southeastward
   into the lower Mississippi Valley. Elevated thunderstorms appear
   likely to be ongoing at the start of the period in eastern Oklahoma
   near a surface low along the western edge of the low-level jet.
   During the day, the low-level jet is forecast to develop southward
   into the Sabine River valley. Warm advection associated with this
   feature along with surface heating will help convection to develop
   across the warm sector during the late morning and early afternoon.
   Surface-based thunderstorms also appear likely to develop along a
   warm front extending east-southeastward across north-central
   Louisiana and along the cold front extending southwestward across
   east Texas. During the late afternoon and early evening, a
   squall-line is expected to organize and move east southeastward
   across the slight risk area reaching the central Gulf Coast late in
   the period.

   Concerning Wednesday's scenario, the models present many different
   scenarios but hint at the possibility of squall-line developing
   during the event.  It seems that early in the event before the
   squall-line develops, storms will have a chance to remain discrete
   as scattered cells initiate across the warm sector in east Texas and
   Louisiana during the early to mid afternoon. NAM forecast soundings
   across the warm sector at 21Z show a very moist environment with
   surface dewpoints in the lower 70s F and MLCAPE values in the 2000
   to 4000 J/kg range. In addition, wind profiles (0-6 km shear in the
   45 to 50 kt range) along with 0-3 km storm relative helicities of
   350 to 450 m2/s2, should support supercells with large hail and a
   potential for tornadoes. The greatest tornado threat is forecast
   along and just to the south of the warm front which should be
   situated from near Tyler, Texas east-southeastward to near
   Alexandria, Louisiana. An enhanced risk has been added along this
   corridor to reflect a greater severe threat including a potential
   for tornadoes. At this point, it remains unclear how long it will
   take for the linear mode to become favored. The current thinking is
   that a gradual transition from discrete to linear mode will take
   place during the afternoon with a squall-line becoming organized by
   late afternoon or early evening. After a squall-line becomes
   organized, the favored severe threat will be for damaging wind gusts
   although hail and brief tornadoes will be possible with rotating
   cells embedded in the line. The squall-line should move across
   southern Mississippi and southeastern Louisiana during the mid to
   late evening.

[Jim Martin]

Northeast of Houston, Texas tomorrow evening.

[MattPetrulli]

Could be a nice sleeper threat, reminds me a lot of 4/2/17 though. 

[andyhb]

1 hour ago, MattPetrulli said:

Could be a nice sleeper threat, reminds me a lot of 4/2/17 though. 

Big difference here is the storm motions (basically to the E this time as opposed to NNE with that event), which will allow a longer residence time within the effective warm sector assuming supercells do develop.

[Indystorm]

As has been mentioned parameters continue to favor the I-10 corridor tomorrow afternoon and evening.

[andyhb]

Euro develops an MCS early and essentially clears out the warm sector preventing much of a threat. That lead shortwave could both hinder and enhance this if the initial development is more discrete.

[Jim Martin]

Interesting solution this evening from the 0z Hi-Res NAM.

[jojo762]

Basing off of current model depictions, and recent HRRR reflectivity iterations, it seems like that significant shortwave that moves through the HGX area around 12Z will likely produce a convective system that will kill anything from happening -- tornado wise-- across the current ENH risk area. Perhaps areas further west could see something during the afternoon, some potential as well in the morning/early afternoon if the storms from that initial S/W remain discrete/semi-discrete, but the HRRR keeps things fairly far south with that initial activity though... which kills instability from returning further north.

[Santa Clause]

Looking rather meh at this point, but this year has just proven again it only takes one.

[monsoonman1]

SPC stays Enhanced risk today with fairly large area of 5% tornado probs, but mentions could be upgraded depending on positions of boundaries, etc.

[monsoonman1]

Tornado watch coming soon for SE TX and South LA.

[pbrussell]

Tornado warned supercells at 9 in the morning. Hmm.

[Santa Clause]

Today looks active to say the least.

[cstrunk]

12 hours ago, Wmsptwx said:

Looking rather meh at this point, but this year has just proven again it only takes one.

 

1 hour ago, Wmsptwx said:

Today looks active to say the least.

Which is it?  Lol

[Santa Clause]

30 minutes ago, cstrunk said:

 

Which is it?  Lol

To be fair, I meant meh in tornado threat, it appears very active for flooding and severe storms. Thanks, I needed to clarify more.

[cstrunk]

2 minutes ago, Wmsptwx said:

To be fair, I meant meh in tornado threat, it appears very active for flooding and severe storms. Thanks, I needed to clarify more.

Gotcha. I wasn't sure if you saw something that made today look better.

I still don't know what to make of the today's threat.

[Santa Clause]

2 minutes ago, cstrunk said:

Gotcha. I wasn't sure if you saw something that made today look better.

I still don't know what to make of the today's threat.

I am an enthusiast and love severe and all that goes into it, but trying to post less and read more to learn more effectively. My guess is flooding is main concern,  and a few brief tornadoes are a possibility, even if it isnt a home run set up.

[Quincy]

2 minutes ago, cstrunk said:

Gotcha. I wasn't sure if you saw something that made today look better.

I still don't know what to make of the today's threat.

Looks like a messy, clustered storm mode, but you can't completely rule out something significant in the mix. Not all that different from 4/2/17, as was brought up before. 

[Chinook]

Areas around Lake Charles have already gotten 3 to 6" of rainfall, as per radar estimate.

[cstrunk]

Well, it was an active severe weather day, but the SPC 10% tornado probabilities earlier pretty much put the Kiss of Death on any spin-ups today. 

[Chinook]

Lake Charles area storm total rainfall up to 1:00AM CDT. Teal values are 8-10". There are a lot of bayou areas down there that can just soak up the rain, but this does affect people.