Short-Term Severe/Flooding Discussion

[Jim Martin]

Two inch hail reported with this storm. Not much movement to this supercell, yet.

[Jim Martin]

Possible tornado NE of Groom, Texas currently.

[cstrunk]

Daniel Shaw is streaming the storm. Someone else was radioing in some dust swirls as a tornado. In any case, there may have been a small funnel and there was definitely no condensation to the ground. 

[Quincy]

1 minute ago, cstrunk said:

Daniel Shaw is streaming the storm. Someone else was radioing in some dust swirls as a tornado. In any case, there may have been a small funnel and there was definitely no condensation to the ground. 

I'm in Groom and the cloud bases were fairly high at the time of the tor warning. A ragged wall cloud is now forming in the NW direction.  

[Jonbo]

There was an incredible hail storm in Hinton, IA on Saturday. Warning, you may want to lower your volume before hitting play. It is extremely loud

 

[Jim Martin]

Possible tornado north of Chester, Oklahoma, moving east.

[Natester]

A little while ago, Daniel Shaw came hurrying back to his car because he got hit right in the head with a golf ball sized hailstone.  His remarks about it was "it hurts like hell".  If the stone were just a bit bigger it could very well have given him a concussion.

[Jim Martin]

Interesting tidbit from the Storm Prediction Center...

  However, strengthening southerly winds across the southern Plains
   this evening, combined with surface vorticity in vicinity of the
   cold front in northern OK to the stationary front extending from the
   eastern TX Panhandle to west TX suggest some increase for a tornado
   threat will be possible this evening.  23Z RAP analysis indicated
   large 0-3 km CAPE juxtaposed with the greater surface vorticity in
   the TX Panhandle to west TX, suggesting a tornado threat, at least
   for early this evening.

[Chinook]

possible tornado near Woodward, OK, which was, I guess yesterday's storm chaser target. Or something like that.

[Jim Martin]

Fun is just beginning in western Oklahoma.

[cstrunk]

The Chester, OK storm has a southward storm motion to it, while the Oakwood storm isn't moving much (slightly north?). How cool would it be to be sitting somewhere in between the two storms and see a distant tornado on each?

In fact, it would be interesting to hear if anyone knows of such an occurrence, where you are able to see more than one storm from the same location, each with a tornado visible. I've had dreams/nightmares of it happening, LOL. And no, I'm not talking about multiple tornadoes/wall clouds/areas of rotation on one storm, I'm talking about completely separate cells.

[Jim Martin]

No true storm motion tonight. Storms going east, west, north, and south tonight.

[cstrunk]

SPC has an enhanced risk across much of Iowa with a 10% tornado area in western/central Iowa.

 

[cstrunk]

If I were chasing today, I'd be targeting SE Nebraska in the Seward area and adjust as needed from there.

A secondary target would be central Kansas, in the Great Bend to Salina region. Both the NAM and HRRR develop what looks like a nice supercell in the same area, as a tail-end Charlie. 

[jojo762]

Shifted the 10% TOR a tad further west at 1630Z. Latest HRRR runs seems to support a longer-duration of discrete/semi-discrete activity, so we'll see if we can get anything out of today. 

[the ghost of leroy]

25 minutes ago, jojo762 said:

Shifted the 10% TOR a tad further west at 1630Z. Latest HRRR runs seems to support a longer-duration of discrete/semi-discrete activity, so we'll see if we can get anything out of today. 

You headed out to chase today?

[Jonbo]

I'm rushing to get my phone factory reset and hope it fixes problems taking pictures (my only camera for the moment) and other things. Seems I won't have to go very far if today pans out as expected around here.

[jojo762]

28 minutes ago, cmasty1978 said:

You headed out to chase today?

Nope. I live near Wichita so this isn't really in my neck of the woods. Wouldn't mind driving up to Salina though to see if anything discrete fires up near there, but I don't think its worth it today. Anyways, almost all the CAMs seem in good agreement on several discrete/semi-discrete supercells going up in SE NE/W IA within the 10% TOR by 21-22Z, so things could get interesting later on along the warm front.

[the ghost of leroy]

i'll probably head out towards salina once i get off work

[jojo762]

Low-level VWP at KOAX is pretty nasty. Winds at 2KFT are east-southeast at 20kts, and winds at 9KFT are southwesterly at 50kts, creating a nearly 90-degree angle and a whole lot of directional and speed shear. Not entirely sure since the wind profile isn't complete so the SRH won't show on the VWP hodographs, but believe 0-3km SRH is currently 300-400+ m2/s2 at OAX, which is obviously favorable for tornadoes... Doubt it will change too much by CI as the warm front should remain in the general vicinity. 

[jojo762]

 
Mesoscale Discussion 0519
   NWS Storm Prediction Center Norman OK
   0229 PM CDT Wed Apr 19 2017

   Areas affected...Parts of sern NE...swrn IA...nwrn MO...n cntrl/nern
   KS

   Concerning...Severe potential...Watch likely 

   Valid 191929Z - 192200Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Thunderstorm development with increasing severe weather
   potential is expected by late afternoon.  At least a couple of
   severe weather watches are likely to be issued across the region by
   21Z.

   DISCUSSION...A cyclonic mid/upper jet streak (including 50+ kt at
   500 mb) is in the process of nosing through the central Plains and
   mid Missouri Valley region.  Strongest forcing for ascent in the
   exit region of this feature likely will remain focused well to the
   cool side of a fairly sharp surface frontal zone, along which a
   modest surface cyclone is now beginning to migrate east northeast of
   the central Nebraska/Kansas border area.  At the same time, the nose
   of a plume of warm and capping elevated mixed layer air is wrapping
   into the mid Missouri Valley region, across much of the warm/moist
   sector of the surface low, and northward to the cool side of the
   front ahead of the low.

   However, latest model output, including the Rapid Refresh, suggests
   that the leading edge of lower/mid tropospheric cooling is now
   roughly near/east of the Grand Island NE through Russell KS.  As
   this continues to spread east northeastward this afternoon, guidance
   indicates that it may provide the focus for increasing thunderstorm
   development by 21-23Z, from near the surface low southward along the
   dryline (as it is overtaken by the southward advancing cold front)
   into parts of central Kansas.

   In the presence of thermodynamic profiles characterized by very
   steep mid-level lapse rates and mixed layer CAPE on the order of
   1500-2000 J/kg, deep layer shear appears more than sufficient for
   supercells.  Near a 40 kt southerly 850 mb jet, sizable clockwise
   curved low-level hodographs will contribute to a risk for tornadoes.
    The extent of the tornado threat remains a bit uncertain due to an
   expected tendency for fairly deep boundary layer mixing and some
   drying within the warm sector, and rather cool/stable air to the
   north of the front.  Any tornadic potential may tend to be maximized
   within a rather narrow corridor along and to the north of the warm
   front, just ahead of the surface low, across parts of southeastern
   Nebraska into southwestern Iowa.

   ..Kerr/Thompson.. 04/19/2017

[Jim Martin]

[Jim Martin]

[Santa Clause]

Yearly trend continues on, just not coming together in one way or another.

[Stebo]

5 minutes ago, Wmsptwx said:

Yearly trend continues on, just not coming together in one way or another.

What yearly trend is that? We have had several events that have been significant, today wasn't a mind blowing day. Still severe storms out there but not tornadic, not exactly what I would call a bust. If the entire area was capped and nothing was happening then we'd be talking differently. 

[Hoosier]

29 minutes ago, Stebo said:

What yearly trend is that? We have had several events that have been significant, today wasn't a mind blowing day. Still severe storms out there but not tornadic, not exactly what I would call a bust. If the entire area was capped and nothing was happening then we'd be talking differently. 

Can't say it's been a quiet start, overall.  If you just look at tornado reports, there aren't many years outdoing this one so far.

 

[Stebo]

1 minute ago, Hoosier said:

Can't say it's been a quiet start, overall.  If you just look at tornado reports, there aren't many years outdoing this one so far.

 

Yeah so if anything today was a bust compared to other days which have yielded, just really a comment that made no sense.

[Indystorm]

Radar confirmed tornado just south of Carroll Iowa., which is now svr warned.

[Chinook]

For Friday afternoon, the 00z GFS has fairly significant winds from 925mb - 700mb, leading to SRH values over 450 m2/s2 north of Fort Worth. This may be the main (remaining) reason to consider a higher tornado potential. And the GFS may be too high with the shear there. The NAM has much lower SRH, like 150 m2/s2. The 00z NAM (12km and 3km) have very cool air in Oklahoma, owing to high amounts of morning rainfall. I think it's still possible there could be something like an enhanced hail/wind outlook for North Texas and the Red River.

[Quincy]

The hires NAM shows a fairly messy setup with faster progression of a cold front through Oklahoma. The RGEM is much closer to the GFS and shows a surface low passing very close to OKC at 00z SAT with a warm front-like boundary draped from roughly OKC-FSM. The Euro is more of a compromise between the two "extreme" solutions and may be the most reasonable at this juncture. 

Before I post the 00z OKC RGEM forecast sounding, I want to make it clear that this is likely one of those setups that doesn't come into really clear focus/reasonable confidence until the morning of. So many things can adjust the mesoscale setup, including, but not limited to: early day convection, effective warm front position, any outflow boundaries, capping (or breaching of cap into N TX), speed of cold front and orientation of shear vectors WRT cold front/dryline.

Modify this RGEM sounding for areas just E/SE of OKC and that spells big trouble.

If the cap can be breached into North Texas (as the RGEM attempts to do), I'd almost prefer that area. That's far too conditional in an already cloudy short range convective forecast.