May 7th-10th Severe Outbreaks

[Quincy]

It's very early in the game and let's not call anything off. Similar talk on 4/24 and this is a much more volatile environment. Keep in mind that the ingredients for tornadoes are maximized between about 22z and 03z. Some junk comes up in the Texas panhandle. Okay. Even if we get a mixed storm mode toward northwest Texas and far southwestern Oklahoma, there is still an elevated threat of tornadoes. (An entirely discrete mode would yield a higher-end threat). I could see a few significant tornadoes today basically on either side of the Red River from CDS back to about I-35. Give it time.

[brettjrob]

Red box out before 10am. Explosive convection with 50kft tops already underway across the South Plains, 3-4 hours in advance of the latest HRRR forecasts. Yesterday, the morning HRRR also waited too long to initiate and grow upscale the convection coming out of this region, and also drastically underforecast the resulting cold pool (which likely blocked a significant event from occurring in NW TX). I can't see much of any reason for optimism at this point. With the obligatory disclaimer: yeah, there could be spinups with these cells as they move into a relatively favorable environment this afternoon, there's some chance of isolated redevelopment back to the W later in the afternon within a 20 mi. wide instability axis, yadda yadda.

[andyhb]

Red box out before 10am. Explosive convection with 50kft tops already underway across the South Plains, 3-4 hours in advance of the latest HRRR forecasts. Yesterday, the morning HRRR also waited too long to initiate and grow upscale the convection coming out of this region, and also drastically underforecast the resulting cold pool (which likely blocked a significant event from occurring in NW TX). I can't see much of any reason for optimism at this point. With the obligatory disclaimer: yeah, there could be spinups with these cells as they move into a relatively favorable environment this afternoon, there's some chance of isolated redevelopment back to the W later in the afternon within a 20 mi. wide instability axis, yadda yadda.

 

I think we need to see how far this convection moves northeast before any MCS development before calling anything, personally.

[rolltide_130]

I think we need to see how far this convection moves northeast before any MCS development before calling anything, personally.

Still staying discrete. Also has more of a northerly track than a NE track. Provided it doesn't keep backbuilding, this could miss the main area of concern entirely.

[cstrunk]

Last few HRRR runs seem to favor NW TX and the area around Wichita Falls. NAM 4KM seems to agree, albeit just a hair farther north.

[Quincy]

Radar looks nothing like it did 24 hours ago. Still not seeing much significant convection east of Lubbock. While we may not fully take advantage of the setup, you can't overlook the shear that's advecting into place and instability progs for later on. Mesoanalysis sig tor up to 2 already in west Texas. Like Ian, I'd favor near to a bit south of the Red River.

[KSWx]

55kft top on that Floydada storm; must be putting down some nasty hail. 

[geddyweather]

Storm near Plainview TX has a history of producing large hail. Still maintaining a decent area of pink/purple in the core on radar.

[andyhb]

Area near SPS still seems to be good to go later on since ongoing convection has not started its eastward propagation yet and also is lifting north of that latitude. OFB placement favours enhanced SRH through this corridor for any storms that can track near the boundary. In addition the conditions north of the boundary aren't necessarily very cold/dry (ala 5/11 last year), so RFD characteristics may not exactly be crippling towards longer lived tornadic potential. Also this was mentioned elsewhere, but further south in the Lubbock to Midland corridor might offer something up later too, once the ascent from the primary impulse today takes effect. Backing low level flow to the Caprock with mid/upper 60s dewpoints would support this.

[cstrunk]

Area near SPS still seems to be good to go later on since ongoing convection has not started its eastward propagation yet and also is lifting north of that latitude. OFB placement favours enhanced SRH through this corridor for any storms that can track near the boundary. In addition the conditions north of the boundary aren't necessarily very cold/dry (ala 5/11 last year), so RFD characteristics may not exactly be crippling towards longer lived tornadic potential. Also this was mentioned elsewhere, but further south in the Lubbock to Midland corridor might offer something up later too, once the ascent from the primary impulse today takes effect. Backing low level flow to the Caprock with mid/upper 60s dewpoints would support this.

 

I agree with this assessment.  Convection has not ruined the target area yet.  There are 70+ dewpoints feeding into the region and as the boundary/boundaries move into NW TX.

[hm8]

Just a reminder that the HWT is going on now, which means access to a bunch of high-res experimental weenie models/forecasts:

 

http://hwt.nssl.noaa.gov/Spring_2015/

 

 

[Ian]

Boundary around Abilene pushing back north lately. Might be something to watch if it sticks around.

[Ian]

Bigger mod further south.. pulled 10 tor back SW.

[huronicane]

[Superstorm93]

Best parameters remain to the south of the crapvection in the panhandle. Still think we''ll see some discrete activity later today once the LLJ kicks up and this residual convection moves out. 

 

[Smokey_mountain_vols]

****.. I'm hardly in the Enhanced zone anymore lol

[andyhb]

Important to note that the 12z GFS is showing air mass recovery (2000-3000+ J/kg SBCAPE) similar to the NAM for tomorrow east of the dryline across W OK, just without the stronger low level shear the NAM/4 km has.

[Quincy]

MD out for SW OK and NW TX. Tornado Watch likely to be issued shortly. Winds continue to back. 070 at CWC now with a 71F dew-point. Over 3000 J/kg SBCAPE sampled via mesoanalysis at noon on the southern fringe of the MD area. 50-60kt bulk shear up to the Red River.

[yoda]

 

 MESOSCALE DISCUSSION 0543
   NWS STORM PREDICTION CENTER NORMAN OK
   1222 PM CDT FRI MAY 08 2015

   AREAS AFFECTED...WESTERN PART OF NORTH TX/SOUTHWEST OK

   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

   VALID 081722Z - 081845Z

   PROBABILITY OF WATCH ISSUANCE...95 PERCENT

   SUMMARY...SEVERE POTENTIAL IS EXPECTED TO STEADILY INCREASE
   EAST-NORTHEASTWARD THIS AFTERNOON ACROSS ADDITIONAL PORTIONS OF
   NORTH TX INTO WESTERN/SOUTHERN OK...INCLUDING A MULTI-MODAL-RELATED
   TORNADO/LARGE HAIL/DAMAGING WIND RISK. A TORNADO WATCH WILL LIKELY
   BE NEEDED EARLY THIS AFTERNOON.

   DISCUSSION...A COMPLEX STORM MODE INCLUDING SOME LOOSELY CLUSTERED
   SUPERCELLS IS EVOLVING AT MIDDAY ACROSS THE SOUTHEAST TX PANHANDLE
   AND WESTERN PART OF NORTH TX. AIR MASS DESTABILIZATION CONTINUES TO
   STEADILY OCCUR NEAR/JUST NORTH OF A PRIOR OUTFLOW BOUNDARY ACROSS
   WESTERN NORTH TX...WHILE THICKER CLOUD COVER HAS TENDED TO LINGER
   INTO OK AS OF EARLY AFTERNOON. THINKING IS THAT CLUSTERED SUPERCELLS
   WILL TEND TO PERSIST EAST-NORTHEASTWARD POTENTIALLY AS AN
   UPSCALE-GROWING COMPLEX INTO ADDITIONAL PORTIONS OF NORTH TX AND
   ADJACENT WESTERN/SOUTHERN OK CENTERED ALONG THE RED RIVER VICINITY.
   LARGE HAIL WILL LIKELY REMAIN THE PRIMARY RISK IN THE SHORT-TERM
   /EARLY AFTERNOON/...BUT DAMAGING WINDS/SOME TORNADO RISK SHOULD
   BECOME MORE OF A CONCERN AS ADDITIONAL BOUNDARY LAYER HEATING
   OCCURS.

   ..GUYER/CORFIDI.. 05/08/2015


   ATTN...WFO...FWD...OUN...SJT...LUB...AMA...

[Roy]

95 percent...dang.

[geddyweather]

Day 2 updated within the last half hour as well. Looks like the best spot for tornado-producing supercells tomorrow will be along the dry line in Wrn OK and a part of Srn KS. 

[Indystorm]

New tor watch out in expected area up to just sw of OKC and east of Ardmore till 9 CDT.  I am cautiously optimistic on today's potential achievement.

[thewxmann]

Modest tornado probs of 50/20 on the latest watch, especially for Corfidi.

[Indystorm]

There's good insolation ongoing over nw TX areas now with abundant moisture south of that MCS.

[1900hurricane]

There is definitely a fine line from outflow pushing south towards Lubbock. I'm having a hard time telling how far east it goes with the tools I have available to me right now though. Radar is losing it two thousand feet up.

[Smokey_mountain_vols]

I'm just sitting here in Tulsa waiting to get these storms sloppy seconds... We don't need the rain!

[tornadotony]

I'm becoming very concerned about the Red River Valley.  The convection thus far has well to the N and W and SPS.  You have these bands of convection that try to get going oriented NW-SE that haven't fully initiated as of yet.  The environment continues to destabilize in this region.  The FWD 1800 UTC sounding has a large area of CAPE prior to its termination just above 500 mb.  SPC mesoanalysis only indicates about 100-200 m^2/s^2 of eff. SRH, but forecasts that to increase as the afternoon progresses, to around 200-300 m^2/s^2.  T/Td spreads at the sfc are very manageable, ranging from 7-11°F, and the FWD sounding shows quality moisture through the depth of the boundary layer.  I would anticipate development in the next few hours to the southeast of the current convection, and I think the environment will likely be extremely favorable for tornadoes by that time.  In short, I fear we may be facing a localized tornado outbreak along the Red River Valley this afternoon and evening.

[Chinook]

Not sure how today will turn out, but here is a map of the tornado tracks from the historical Red River Valley tornado outbreak of 1979

 

http://www.srh.noaa.gov/images/oun/wxevents/19790410/figures/outbreak.jpg

 

http://www.srh.noaa.gov/oun/?n=events-19790410-burgess

http://www.srh.noaa.gov/images/oun/wxevents/19790410/figures/wfalls2.gif

[Chinook]

Some more substantial storms are forming right over Lubbock and Petersburg. They are tracking into the cold air.

[Ian]

Area SW of Wichita Falls and east of Lubbock looks really solid for sure. Progression so far today does seem to favor nearing/hitting potential later.