March 6th-8th Severe Potential

[Superstorm93]

I don't recall seeing a setup like this before. 

 

 

[NTXYankee]

Probably not a bad thing kids are on spring break down here this week, if something does happen to unfold. Troubling that the models continue to advertise more parameters coming into play and more robust. FWD was leaning towards not much happening Monday night to overturn Tuesday and that continues to be the case with the models.

[ClicheVortex2014]

 

 

DAY 1 CONVECTIVE OUTLOOK 
NWS STORM PREDICTION CENTER NORMAN OK
1132 PM CST SUN MAR 06 2016

VALID 071200Z - 081200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF SRN CA NEAR THE
COAST...

...SUMMARY...
ISOLATED TO WIDELY SCATTERED SEVERE STORMS WITH LARGE HAIL...WIND
DAMAGE AND POSSIBLY A TORNADO OR TWO ARE POSSIBLE ACROSS THE
SOUTHERN PLAINS FROM TODAY THROUGH TONIGHT. STRONG WIND GUSTS AND
HAIL WILL BE POSSIBLE ACROSS PARTS OF THE CENTRAL AND NORTHERN
PLAINS LATE THIS AFTERNOON INTO EARLY THIS EVENING. MARGINALLY
SEVERE WIND GUSTS MAY ALSO OCCUR ALONG THE COAST IN SOUTHERN
CALIFORNIA THIS MORNING AND EARLY THIS AFTERNOON.

...SRN PLAINS...
SOUTHWEST FLOW WILL BE IN PLACE ACROSS THE SRN PLAINS TODAY AS
HEIGHTS FALL AHEAD OF A DEVELOPING UPPER-LEVEL LOW IN THE SWRN
STATES. A BROAD BELT OF STRONG LOW-LEVEL FLOW ACROSS THE SRN PLAINS
WILL SETUP A CORRIDOR OF MOISTURE FROM CNTRL TX NWD INTO OK. SFC
DEWPOINTS ALONG THIS CORRIDOR WILL BE IN THE LOWER TO MID 60S F WITH
MODERATE INSTABILITY DEVELOPING BY AFTERNOON. WEAKLY FORCED
CONVECTION APPEARS LIKELY TO INITIATE ON THE ERN EDGE OF THE
INSTABILITY CORRIDOR AND JUST TO THE WEST OF THE STRONGEST LOW-LEVEL
FLOW LATE THIS AFTERNOON. SEVERAL STRONG TO SEVERE THUNDERSTORMS
WILL BE POSSIBLE AS CONVECTION DEVELOPS AND MOVES NEWD ACROSS CNTRL
AND NORTH TX EXTENDING INTO SRN AND CNTRL OK. NAM FORECAST SOUNDINGS
ALONG THIS CORRIDOR AT 00Z/TUE SHOW MLCAPE NEAR 1500 J/KG AND 0-6
SHEAR OF 50 KT. IN ADDITION...0-3 KM SRH IS FORECAST TO BE IN THE
300 TO 400 M2/S2 RANGE. THIS ENVIRONMENT SHOULD SUPPORT SUPERCELL
DEVELOPMENT AND LOW-LEVEL ROTATION. A TORNADO OR TWO MAY OCCUR ALONG
WITH WIND DAMAGE AND ISOLATED LARGE HAIL.

FURTHER TO THE WEST...A DRYLINE ACROSS WCNTRL TX IS FORECAST TO
RETREAT INTO WEST TX THIS EVENING SETTING UP FROM NEAR MIDLAND
EXTENDING NEWD TO NEAR CHILDRESS BY MIDNIGHT. MODEL FORECASTS
SUGGEST THAT A BAND OF LARGE-SCALE ASCENT WILL MOVE ACROSS WEST
TX...HELPING TO INITIATE SCATTERED THUNDERSTORMS AFTER MIDNIGHT.
THIS CONVECTION IS FORECAST TO MOVE NEWD ACROSS SRN PORTIONS OF THE
CAPROCK AND INTO THE LOW ROLLING PLAINS LATE TONIGHT. FORECAST
SOUNDINGS TO THE EAST OF LUBBOCK AT 09Z/TUE SHOW MLCAPE NEAR 1750
J/KG WITH 60 KT OF 0-6 KM SHEAR AND 700 TO 500 MB LAPSE RATES IN THE
7.5 TO 8.0 C/KM RANGE. THIS SHOULD BE FAVORABLE FOR SUPERCELLS
ALTHOUGH THE STORMS SHOULD REMAIN ELEVATED DUE TO A SFC INVERSION.
ANY SUPERCELL THAT DEVELOPS SHOULD HAVE A POTENTIAL FOR LARGE HAIL
AND ISOLATED DAMAGING WIND GUSTS.

 

Only a tornado or two may occur in that environment... don't worry

[andyhb]

Sort of an oddly placed D1. I know there is signal for convection there, but I would've thought the slight would be demarcated on the western edge by the model consensus placement of the dryline in W OK and W Central KS with a 5% tor there.

[ClicheVortex2014]

Looking at RAP and HRRR soundings, the significant hail parameter is 2-4 over a large portion of the slight risk... I'd imagine there'll be at least some spots that could get upgraded to enhanced tomorrow for hail. May be some really good looking supercells today with some nasty hail cores... looking forward to watching livestreams.

[nwburbschaser]

Looking at RAP and HRRR soundings, the significant hail parameter is 2-4 over a large portion of the slight risk... I'd imagine there'll be at least some spots that could get upgraded to enhanced tomorrow for hail. May be some really good looking supercells today with some nasty hail cores... looking forward to watching livestreams.

I imagine that today could have some nice structure, but that's entirely dependent on storms even forming in the first place. I'm still questioning if that's even going to happen.

[Kaner88]

RAP & HRRR have been ridiculously over-doing dewpoints in recent runs, I found 0z NAM (and 6z, to a degree) to be most accurate. 

I'm not sure what to expect, but the general chatter around here in Norman has been for a primary hail threat, as has already been alluded to.

[HillsdaleMIWeather]

Really feels like the SPC is downplaying tomorrow's threat. Never a good idea.

[monsoonman1]

Already ~60 degree dews in OK. Wonder if there will be any subtle/mesoscale forcing that can get storms to initiate on the dryline today. Regarding tomorrow's risk, seems like the SPC is waiting to get a bit clearer picture. Wouldn't be too surprised to see a big Enhanced or even a Moderate risk tomorrow, certainly has potential.

[JasonOH]

I don't have class this afternoon, so I am going to chase and hope for the best. I am planning on leaving Norman at noon and going west toward Weatherford as of now. I think the best chance of intition will coincide with a bulge in the dryline, so we will have to adjust our initial target as time goes on. I am not expecting to get any tornadoes, but hopefully we can get a nice LP or classic supercell out on the dryline IF (that's the key word here) initiation occurs.

[monsoonman1]

Interestingly, latest HRRR showing supercells in NW OK/SW KS around 8 pm. Likely high-based with some big hail.

[ClicheVortex2014]

Interestingly, latest HRRR showing supercells in NW OK/SW KS around 8 pm. Likely high-based with some big hail.

I think the discrete supercells on the OK/KS border on the HRRR could be more interesting... the environment is much more favorable.

 

 

Sounding in the vicinity

 

[monsoonman1]

Looks like LCL's might be low enough for a tor or two. It would be nice if something happened on the dryline, anyway.

[nwburbschaser]

Really feels like the SPC is downplaying tomorrow's threat. Never a good idea.

If you're going to play the call out the SPC game then you really need to have something to support your claims. I would just avoid it in the first place, but definitely don't make a post about them downplaying a threat without explaining your reasoning for that thought. 

 

I don't see any big issue here so maybe you could have enlightened us all to something. 

[andyhb]

If you're going to play the call out the SPC game then you really need to have something to support your claims. I would just avoid it in the first place, but definitely don't make a post about them downplaying a threat without explaining your reasoning for that thought. 

 

I don't see any big issue here so maybe you could have enlightened us all to something. 

 

Thank you for doing this more nicely than I would have, lol.

[ClicheVortex2014]

Forbes downgraded the threat from a 5 TORCON to 4 tomorrow. He kept today at a 4 as well

[David Reimer]

Forbes downgraded the threat from a 5 TORCON to 4 tomorrow. He kept today at a 4 as well

 

Forbes and his TOR:CON can go... well somewhere the sun doesn't shine very often. That stupid thing creates more confusion than not. Go find a few comments from James Spann when it comes to TOR:CON. 

[andyhb]

No mention of tornadoes in the new D2.

[SmokeEater]

Really feels like the SPC is downplaying tomorrow's threat. Never a good idea.

What are they downplaying? Half assed bashing SPC for no reason, while you have nothing to say about it, doesn't make you look too smart. Both days are starting to look marginal, tomorrow being a little better then today. Neither look like outbreaks, enhanced for tomorrow is more then fine. Don't worry, there aren't any high wind warnings needed in the area, lol.

[ClicheVortex2014]

Forbes and his TOR:CON can go... well somewhere the sun doesn't shine very often. That stupid thing creates more confusion than not. Go find a few comments from James Spann when it comes to TOR:CON. 

I disagree. It's good for letting the general public know their subjective severe threat, especially since the general public doesn't read SPC or NWS technical discussions. The best they have is local TV stations. Forbes one of the most experienced severe weather experts alive today... if not the most. I use TORCON to see his thoughts on the highest relative threat area, and I hold his opinions higher than SPC's.

 

Some strong cells are popping in central Texas. The parameters are favorable for these to become supercells with large hail, especially since mid-level lapse rates are approaching 9 C/km

[Quincy]

Today's optimal chase target is western Oklahoma to south-central, Kansas, IMO. Storm mode looks messy to the east, with issues around instability and terrain. 

 

The best overlay of ingredients (shear/instability), including the most substantial height falls, favors the western target. Storms should also be relatively isolated. Not a slam dunk tornado setup, but there is a narrow window for a tornado or two. The most likely scenario is at least a couple of photogenic supercells.

[jojo762]

Dr. Forbes isn't wrong very often, don't see the need in bashing him? He learned from the proverbial "God" of tornadoes.

[JoMo]

I disagree. It's good for letting the general public know their subjective severe threat, especially since the general public doesn't read SPC or NWS technical discussions. The best they have is local TV stations. Forbes one of the most experienced severe weather experts alive today... if not the most. I use TORCON to see his thoughts on the highest relative threat area, and I hold his opinions higher than SPC's.

 

Some strong cells are popping in central Texas. The parameters are favorable for these to become supercells with large hail, especially since mid-level lapse rates are approaching 9 C/km

I don't know about that. I'm pretty confused right now myself on what to expect in my area. Forbes has a TOR:CON of 2-3 tonight for my area. I'm not even in the marginal risk according to SPC. Yet with Forbes scale I can expect something in between a low to moderate chance of a tornado? 

[SmokeEater]

Dr. Forbes isn't wrong very often, don't see the need in bashing him? He learned from the proverbial "God" of tornadoes.

Nobody's bashing Forbes himself, just the torcon index. A lot of very well known, experienced mets, etc can't stand it, and say the same thing David did. That all it does is confuse the public. Example being what JoMo said. Nobody alive I don't think would bash Forbes himself.

[JasonOH]

Just passing though El Reno on my way to Clinton. Nice clearing on satellite and the HRRR is being nice to the area. Hoping for some nice supercells with great structure.

On another note, the TWISTEX memorial is beautiful if you are ever near El Reno.

[ClicheVortex2014]

I don't know about that. I'm pretty confused right now myself on what to expect in my area. Forbes has a TOR:CON of 2-3 tonight for my area. I'm not even in the marginal risk according to SPC. Yet with Forbes scale I can expect something in between a low to moderate chance of a tornado? 

The basis upon which TORCON is designed is weird, but it doesn't take a genius to figure out that a TORCON of 2-3 means a low chance for a tornado in your area, and a TORCON of 7 is high. Dr. Forbes himself has said when he issues a value greater than 6, there's a greater chance for strong tornadoes. So even he has his TORCON separated by categories.

 

It's really not much different from what SPC uses. Their probabilistic outlook says there's a 5% chance of seeing a tornado in a 25 mile radius. I don't think any of us take it verbatim that there's an actual 5% chance... we see it as a category. 5% would be a low to low-medium threat (i.e., slight risk). If we see the SPC outline a 60% tornado area, we're gonna look at that and say something massive is probably gonna happen in that area. Not that, 6 times out of 10, there'll be a tornado in a 25 mile radius. 

 

Forbes issued a 10/10 for the 2011 Super Outbreak when SPC issued a 4.5/10. But we knew that when SPC issues a 45%, they mean business. 

[andyhb]

Forbes issued a 10/10 for the 2011 Super Outbreak when SPC issued a 4.5/10. But we knew that when SPC issues a 45%, they mean business. 

 

This isn't really how it works. For Forbes, a 9/10 means a 90% chance of tornadoes within 50 miles of a given point. A 45% tor from SPC means a 45% chance of tornadoes within 25 miles of a given point.

 

Anyway, this whole conversation is pretty redundant.

[brettjrob]

I don't really think TOR:CON is a big deal. I'm somewhat sympathetic to the argument that it can potentially created a mixed message with the public vs. SPC categorical outlooks, but the latter really aren't intended for public consumption anyway. The fact that "enhanced" is less dangerous than "moderate" is pretty good evidence of that, I have to say. And Dr. Forbes is legit. Until such a time as the SPC issues public-friendly tornado forecasts with larger lead time than watches -- for example, a "Category 1-5 tornado risk" system corresponding to 5%, 10%, 15%, etc. tor probs on the SWODY1 -- I understand why TWC would put out TOR:CON.

[ClicheVortex2014]

I don't really think TOR:CON is a big deal. I'm somewhat sympathetic to the argument that it can potentially created a mixed message with the public vs. SPC categorical outlooks, but the latter really aren't intended for public consumption anyway. The fact that "enhanced" is less dangerous than "moderate" is pretty good evidence of that, I have to say. And Dr. Forbes is legit. Until such a time as the SPC issues public-friendly tornado forecasts with larger lead time than watches -- for example, a "Category 1-5 tornado risk" system corresponding to 5%, 10%, 15%, etc. tor probs on the SWODY1 -- I understand why TWC would put out TOR:CON.

SPC has sporadically been categorizing their outlooks such as you described on social media, as have local TV Meteorologists.. or at least in the Cincinnati area. That makes me happy because I think categories are the best way to help the public understand the risk. I still do see the need for SPC and Dr. Forbes' separate systems. Both sources are great. Nothing wrong with getting a second opinion, especially when it comes to forecasting. 

[ClicheVortex2014]

A couple of cells have popped on the dryline in SW TX