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2025 Severe Weather General Discussion


Kmlwx
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1 hour ago, Kmlwx said:

NAM and NAM nest seem better with parameters for Thursday now - but sim reflectivity doesn't really have any initiation at least on the panels I've seen (through 0z Fri). 

Right.   Parameters, especially the shear, are very favorable Thursday.  But will there be a trigger?   As you noted, the NAM says no, but the HiResW FV3 opens the door to at least a few cells in the Mid-Atlantic. 

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7 minutes ago, Eskimo Joe said:

Classic issue when we have bad mid level lapse rates and dry air at the surface. Storms just can't get above 10,000 feet and the updrafts kick the storms apart.

And my excuse of "it's still early in the season" gets less relevant each passing day. By April, we often have much better thermodynamic profiles - though May/June would be even better. Though that admittedly won't solve mid-level lapse rates!

I will say - yesterday ahead of the storms did feel juicier than the prior few events this year so far. So we are "getting there" in terms of better dew points and temps. 

One thing I do like is that we haven't had a shortage of "chances" this year so far. While there has sometimes been a week+ between risks, there's been a pretty steady stream of at least potential systems showing up. 

Thursday has my interest at least for now. 

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SLGT risk up for Thursday 2/5/15

.OH Valley into the Mid Atlantic...
   Complications abound from overnight convection likely persisting
   into the daylight hours across the OH Valley. The front is forecast
   to continue to sag south and stall eventually across the OH Valley
   and Mid Atlantic by midday Thursday. South of the boundary low 60s F
   surface dewpoints and some filtered diurnal heating should support
   around 1000 J/kg of MLCAPE. Several embedded mid-level perturbations
   may provide enough ascent for additional convective development
   through the day.  Vertical shear will remain strong as increasingly
   zonal winds aloft overspread the frontal zone. Several clusters of
   strong to severe storms are possible along the front with a risk
   primarily for damaging winds and tornado or two, given the
   relatively poor mid-level lapse rates and veered low-level flow.
 
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2 hours ago, WxUSAF said:

Wide range of options on 12z mesos. I vote FV3.

Yeah, lots of uncertainty, but most of the CAMs (NAM Nest is notably bearish) have at least a couple of cells - a widespread severe event does not appear likely, but localized severe appears to be on the table.  I maintain that there is a slightly higher tornado risk; SPC notes the veered surface winds but that may be offset by a greater westerly component in the flow just above.  
 

More widespread storm coverage may be possible later Thursday night, but these would have very limited severe potential. 

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Day 2 1730z SPC OTLK disco for our region

 

   ...Kentucky to the Mid-Atlantic...
   Day 1 convection and cloud cover will significantly inhibit severe
   weather potential on Day 2 along the frontal zone from Kentucky to
   the Mid-Atlantic. Trimmed probabilities farther south near the Ohio
   River based on latest forecast front location. Otherwise, a moist
   airmass will remain in place along and south of the front/remnant
   outflow. Therefore, only minimal heating will be needed for some
   storms to develop which could be supercellular given 45 to 55 knots
   of effective shear along the frontal zone. Overall height rises
   should keep stronger storm coverage isolated to potentially
   scattered. Some damaging wind/large hail, and perhaps a tornado
   threat may exist within this corridor on Thursday, but the exact
   locations of this threat remains uncertain at this time.
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@high risk why would looping hodos suppress updraft development?  Too much wind shear?

NEAR TERM /THROUGH TONIGHT/...
A warm front lifting north of the area today combined with
southerly flow from high pressure offshore, will lead to plenty
of warm and moist air in the forecast area. Additionally, a
cold front approaching from the west will create an environment
conducive to rain showers and possible severe thunderstorms.
Moderate CAPE, strong shear, and the frontal boundary
approaching during peak heating lead to possible strong to
severe thunderstorms. That being said, model soundings show
looping hodographs, due to wind shear,which may suppress
updraft development.Showers and a few thunderstorms continue
this evening and into the overnight as the cold front moves
through the forecast area.
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I'll take the 06z and 07z HRRR btw.  Wonder if that severe squall line out west will be laying down boundaries for this afternoon 

06z NAM NEST still not enthusiastic for really anything, 06z NAM now shows storms coming in around 21z

00z FV3 also not enthusiastic... 06z RAP seems its very enthusiastic lol

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4 hours ago, yoda said:

@high risk why would looping hodos suppress updraft development?  Too much wind shear?

NEAR TERM /THROUGH TONIGHT/...
A warm front lifting north of the area today combined with
southerly flow from high pressure offshore, will lead to plenty
of warm and moist air in the forecast area. Additionally, a
cold front approaching from the west will create an environment
conducive to rain showers and possible severe thunderstorms.
Moderate CAPE, strong shear, and the frontal boundary
approaching during peak heating lead to possible strong to
severe thunderstorms. That being said, model soundings show
looping hodographs, due to wind shear,which may suppress
updraft development.Showers and a few thunderstorms continue
this evening and into the overnight as the cold front moves
through the forecast area.

I’m not totally sure, but I think they’re referring to the profiles having stronger winds in the mid levels and then weaker winds above, creating looping hodographs.   Those can sometimes prevent proper tilting of the updraft/downdraft structure needed to maintain persistent strong updrafts.   We’ll see if the upper level winds are really weaker.  

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Just now, high risk said:

I’m not totally sure, but I think they’re referring to the profiles having stronger winds in the mid levels and then weaker winds above, creating looping hodographs.   Those can sometimes prevent proper tilting of the updraft/downdraft structure needed to maintain persistent strong updrafts.   We’ll see if the upper level winds are really weaker.  

I'm pretty close to calling you out as a meteorology AI robot. You always have superb explanations and insight. We're watching you though....robot.

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2 hours ago, Kmlwx said:

CSU MLP for today

image.thumb.png.f232a9f8f89fb081bfc7b287fe28daa7.png

I’ve been saying that today has some sneaky tornado potential, confirmed by the CSU prog above.  I think that storm rotation is somewhat likely today but 1) I’m still unsure about storm coverage 2) sfc winds might be a bit weak too weak
 

let’s see how much we warm this afternoon. Nam nest has the coolest temps and therefore the least storm coverage. 

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2 minutes ago, high risk said:

I’ve been saying that today has some sneaky tornado potential, confirmed by the CSU prog above.  I think that storm rotation is somewhat likely today but 1) I’m still unsure about storm coverage 2) sfc winds might be a bit weak too weak
 

let’s see how much we warm this afternoon. Nam nest has the coolest temps and therefore the least storm coverage. 

It's seems like one of those weird conditional severe days where coverage is low, and who knows if we'll even see any storms pop during peak time - but if one goes up it could really dominate even if isolated. 

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2 hours ago, Kmlwx said:

It's seems like one of those weird conditional severe days where coverage is low, and who knows if we'll even see any storms pop during peak time - but if one goes up it could really dominate even if isolated. 

Sounds in some ways similar (though far less potential) to last years mini tornado outbreak 

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Which is interesting because if you take a peak at the 12z NAM Nest soundings, you'd think something would go.  But looking deeper, I see ConvT is 84 degrees - so I'm assuming that since we aren't forecasted to reach that temperature, the NAM Nest sim radar isn't showing convection.  Am I reading that correctly or am I offbase?

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