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Severe Weather 2025

WPC Day 3 Discussion seems to be giving subtle hints of a Moderate Risk upgrade for flash flooding.
"Day 3
Valid 12Z Tue Feb 11 2025 - 12Z Wed Feb 12 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
THE MID-SOUTH AND LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE
VALLEY...

...ArkLaTex-ArkLaMis into the Mid-South and Tennessee Valley...
Strong NW-SE upper level jet streak will dive southeast into CA
late on Day 3 (Tue night) -- on the western periphery of the
longwave trough towards the base. As this occurs, the broad western
U.S. trough will amplify, thereby enhancing the deep-layer ascent
and southwesterly flow/moisture transport within a maturing Warm
Conveyor Belt (WCB) downstream across the Mid South-Lower MS Valley
and TN Valley. 850-700 mb moisture flux anomalies increase to 2-3
standard deviations above normal Tue-Tue night, while TPW values
climb to 1.5-1.75" (around +2 standard deviation above normal). The
strengthening dynamical and thermodynamical support will make for
efficient rainfall rates despite the lack of deep-layer
instability. Much of the guidance, non-CAM at this point being a
Day 3 forecast, depicts a widespread swath of 1.5-2.5" of rain
within the outlook areas, with more stripes of >3" within the
Slight Risk area. Storm motions nearly parallel to the WSW-ENE
oriented surface boundary will boost the potential for training,
and even though currently the non-CAM guidance is advertising
meager deep-layer elevated instability (MUCAPEs generally 250-500
J/Kg), believe these values will be amplified somewhat as the event
gets within the high-res CAM windows, again given the dynamic and
thermodynamic response to the broad-scale upper trough amplification.

2.00"+/3hr rainfall rates are anticipated where the cells do
train, again most likely within the Slight Risk area, which could
lead to localized-scattered instances of flash flooding."
 
Early peek on the NAM at our potential environment late Wednesday into Thursday. Rather surprised by forecast instability, especially considering it's the NAM, but we'll see if that trend continues or not. Definitely something to keep an eye on if you're in LA, MS or AL.
1739139120278.png1739139146098.png
 
Clancy said:
Early peek on the NAM at our potential environment late Wednesday into Thursday. Rather surprised by forecast instability, especially considering it's the NAM, but we'll see if that trend continues or not. Definitely something to keep an eye on if you're in LA, MS or AL.
View attachment 33485View attachment 33486
Click to expand...
da fuq, I'd def wait until more models can be used and if those too show this, then we have an issue, like ya said, something to def watch.
 
It's not just the NAM being the NAM, unless GFS and Euro are also just being the NAM... since they both show a 1000-1600 SBCAPE environment and mid/upper 60 dewpoints south of the effective warm front over southern AL/MS Wednesday afternoon. They just have the boundary a bit farther south than the NAM's location because of the widespread heavy rain and elevated storms to its north (which is likely correct). They both also show that instability coupled with favorable deep-layer and low-level wind shear. The main reason the SPC doesn't have a risk area outlined yet is because they have questions about degree of forcing south of the boundary. My questions about that aren't as strong as theirs, but I can understand it. But no, that's not just the NAM pulling something out of nowhere. The Gulf has essentially been getting primed for over a week now, and the current frontal passage over the Southeast is not pushing upper 60 and lower 70 dewpoints out of the northern Gulf. Add to that a low amplitude flow in the mid/upper levels originating from steeper lapse rates out over the Southwest and northern Mexico, it shouldn't be any surprise in the least that models are showing instability supportive for severe weather south of the frontal boundary this week.
 
And for what it's worth, there will probably be another severe threat over the Southeast on Saturday. It may be more expansive than whatever happens Wednesday. There are just questions about surface low and warm frontal placement that can't be answered yet. Models are still trying to figure out synoptic trough geometry, which affects the surface low placement and intensity, which then affects warm frontal placement and northward extent of the warm sector.
 
Day 6: Saturday:

fema04_swody6_PROB.png
There has been a consistent signal for a potent upper-level trough
to move into the West Coast on Friday. In response to this trough, a
deep surface low is expected to develop in eastern Colorado and move
into Oklahoma. These features will promote strong moisture return
into parts of the central Gulf Coast states late Friday into
Saturday. Appreciable moisture return may reach into the Mid-South.
This setup would favor scattered to numerous severe storms from the
Sabine Valley vicinity into much of Mississippi/Alabama. Both
low-level and deep-layer shear would be strong in this regime. The
surging cold front will likely be the primary focus for storms, but
the strong synoptic forcing within a potentially weakly capped
boundary-layer could also bring about more discrete storms ahead of
the line as well. The primary uncertainties will be the
timing/amplitude of the trough as well northward/eastward extent of
sufficient buoyancy. With the consistent signal in deterministic and
ML guidance, 15% severe probabilities appear warranted for Saturday.
Refinement of the highlighted area is probable as additional data
becomes available.
Click to expand...
 
Absolutely shocking..... LOL!
 
Wowsers. 15th time frame looks potent at a glance. Quite concerned, as it stands, about the wide areal extent. Impressive CAPE for February modelled as well. SPC mentions QLCS situation with discrete ahead of the line.
...Southeast...
There has been a consistent signal for a potent upper-level trough
to move into the West Coast on Friday. In response to this trough, a
deep surface low is expected to develop in eastern Colorado and move
into Oklahoma. These features will promote strong moisture return
into parts of the central Gulf Coast states late Friday into
Saturday. Appreciable moisture return may reach into the Mid-South.
This setup would favor scattered to numerous severe storms from the
Sabine Valley vicinity into much of Mississippi/Alabama. Both
low-level and deep-layer shear would be strong in this regime. The
surging cold front will likely be the primary focus for storms, but
the strong synoptic forcing within a potentially weakly capped
boundary-layer could also bring about more discrete storms ahead of
the line as well. The primary uncertainties will be the
timing/amplitude of the trough as well northward/eastward extent of
sufficient buoyancy. With the consistent signal in deterministic and
ML guidance, 15% severe probabilities appear warranted for Saturday.
Refinement of the highlighted area is probable as additional data
becomes available.
Click to expand...
1739204595915.png
1739204618804.png1739204634007.png
1739204683788.png1739204708370.png
 
UncleJuJu98 said:
So when we making a thread? Its going to get busy/crowded in here pretty quick I imagine lol.
Click to expand...
talkweather.com

2.12.25-2.14.25 Winter Weather Threat (Southeastern U.S.)

The Models runs of the GFS, ECMWF and other models have a decent winter storm setup for the Southeastern U.S. Where I am at (In Virginia) we are expecting 4-5 inches of snow tomorrow, and at least an inch of ice is possible the next day. The system eventually lifts northwards. EDIT: THREAD...
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