Short-Term Severe/Flooding Discussion

[Jim Martin]

TXC069-150200-
/O.CON.KLUB.TO.W.0019.000000T0000Z-170415T0200Z/
Castro TX-
850 PM CDT FRI APR 14 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 900 PM CDT FOR NORTHERN
CASTRO COUNTY...
    
At 847 PM CDT, a severe thunderstorm capable of producing a tornado 
was located near Dimmitt, moving east at 10 mph.  The greatest area 
of concern is about 3 miles southeast of Dimmitt.  A second area of 
rotation was located about 12 miles west of Dimmitt.  These storms 
continue to evolve and require constant monitoring.

[Chinook]

I just started looking at radar, and I can only grab data that is less than 1 hour old. Did the storm cycle, and produce a 2nd tornado southwest of the original? Not sure. Pretty incredible radar images.

[Jim Martin]

1 minute ago, Chinook said:

I just started looking at radar, and I can only grab data that is less than 1 hour old. Did the storm cycle, and produce a 2nd tornado southwest of the original? Not sure. Pretty incredible radar images.

This storm has been going for at least the last two to three hours Chinook. To me, it draws comparison to Greensburg KS from May 2007 based on radar.

[Jim Martin]

Now it has evolved to be twin supercells.

[Jim Martin]

The anvil from this evolving supercell is now into Kansas based on satellite returns.

[Chinook]

I might have to go to the NCDC radar archive after this storm is over, so I can see it all on my GRLevel3 screen. Were these tornadoes known to have tracked over many farm structures?

[Jim Martin]

1 minute ago, Chinook said:

I might have to go to the NCDC radar archive after this storm is over, so I can see it all on my GRLevel3 screen. Were these tornadoes known to have tracked over many farm structures?

Not exactly sure Chinook.

[cyclone77]

Pretty amazing radar loop from this thing.  

http://weather.cod.edu/satrad/nexrad/index.php?type=AMA-N0Q-1-96

[Chinook]

now there's rotation over the exact same area as previous tornado report(s). The NWS does not have a tornado warning for this.

[weatherextreme]

1 hour ago, Chinook said:

I might have to go to the NCDC radar archive after this storm is over, so I can see it all on my GRLevel3 screen. Were these tornadoes known to have tracked over many farm structures?

Found this video from another weather site

 

 

[SmokeEater]

I just started looking at radar, and I can only grab data that is less than 1 hour old. Did the storm cycle, and produce a 2nd tornado southwest of the original? Not sure. Pretty incredible radar images.

It's produced many tornadoes, some up to a mile wide. Insane storm.

[andyhb]

15 minutes ago, SmokeEater said:

It's produced many tornadoes, some up to a mile wide. Insane storm.

That big one was down for at least half an hour unless it cycled in between scans. Certainly not something I saw coming today, but favorable low level winds can lead to strange things when combined with 2500 J/kg MLCAPE. Noteworthy that the 500 mb flow was only around 15 kts in the area where this cell set up shop.

[SmokeEater]

The monster, pic from Marcus Diaz. Whole damn meso is on the ground.

[SmokeEater]

4 minutes ago, andyhb said:

That big one was down for at least half an hour unless it cycled in between scans. Certainly not something I saw coming today, but favorable low level winds can lead to strange things when combined with 2500 J/kg MLCAPE. Noteworthy that the 500 mb flow was only around 15 kts in the area where this cell set up shop.

You and a ton of chasers, lots of implosions on FB tonight.

[Quincy]

53 minutes ago, andyhb said:

That big one was down for at least half an hour unless it cycled in between scans. Certainly not something I saw coming today, but favorable low level winds can lead to strange things when combined with 2500 J/kg MLCAPE. Noteworthy that the 500 mb flow was only around 15 kts in the area where this cell set up shop.

The 00z AMA sounding looked awfully weak in the 500mb layer, but mesoanalysis indicated about 30kts of h5 flow at 23z INVOF the cell. That translates to ~15 m/s, which is still unusually low for tornadogenesis. Seasonably large CAPE values (2500-3000 J/kg mixed layer) helped offset the lower-end shear. 

[Torchageddon]

I'm in agreement with that being storm of the year to this point, three High Risks in and this was on a day that wasn't one to watch. Its pretty much a law at this point that the memorable insane stuff tends to be when there is little to no hype nowadays and vice-versa. The risk outline from the Day 1 gave me a smirk, those tiny Sights circled spots where the severe cells are. When I checked the reports map and saw where the tornado was, I thought "Lazbuddie" and yep that location was in there lol. Did I read a place called Easter in the tornado warning?

1 hour ago, SmokeEater said:

You and a ton of chasers, lots of implosions on FB tonight.

Implosions?
 

[Chinook]

Sometimes you just get 3000 J/kg of CAPE near a dryline and then something awesome happens, when 0-6km shear is a little better than previously thought. Yesterday, I was thinking,

"Friday is going to be one of those oops days where there's a marginal risk on the day-2 and then it'll turn out that some chaser catches some cool brief tornado."  But I didn't know where. And I didn't know it would be -that- interesting or -that- wide. And I'm not out in Kansas driving around for this stuff.

 

Here is a HRRR sounding just south of the storm at 00z. The SRH increased quickly (I believe) near the storm. Hope this helps. Were the 1.5km winds really -that- high?

[Drz1111]

9 hours ago, SmokeEater said:

The monster, pic from Marcus Diaz. Whole damn meso is on the ground.

Based on what was posted to YouTube this AM, lots of the chasers on the first tornado ended up on the wrong side of the rain shaft wrapping around the wedge.  Diaz's 45 second teaser is easily the best video of the big one.

[Jim Martin]

Risk of severe weather once again today.

[Jim Martin]

Of all the Convective Allowing Models, the 12z NSSL WRF-ARW is indicating potential for a couple of isolated supercell thunderstorms later today in the Oklahoma and Texas Panhandles, and into far Northwest Oklahoma.

[andyhb]

NCAR ensemble (which performed quite well yesterday) was also pinpointing that area for a heightened risk. Sitting right on the southern periphery of the vort max passing to the north with slightly strengthened flow aloft as a result. There's a plume of low 60s dewpoints lurking to the south with 8.5-9+ C/km 700-500 mb lapse rates over the region currently, those two combined should yield some impressive CAPE later on. Low level flow doesn't look quite as favorable (strength wise) as it was yesterday, although there is certainly some decent veering in the lowest km.

[Jim Martin]

The current SPC Mesoanalysis Mixed Layer Convective Available Potential Energy.

[WhiteoutWX]

Currently winds are out of the SW in northwest OK and the TX panhandle. Doesn't exactly get me enthused about tornado potential 

[andyhb]

17 minutes ago, WhiteoutWX said:

Currently winds are out of the SW in northwest OK and the TX panhandle. Doesn't exactly get me enthused about tornado potential 

That should change later on as the vort over the NM/CO border shifts east and the surface low deepens over the western OK Panhandle. Mid 60s dewpoints over SW OK right now via the mesonet, should be game on if those get anywhere near the triple point.

[bjc0303]

1 hour ago, WhiteoutWX said:

Currently winds are out of the SW in northwest OK and the TX panhandle. Doesn't exactly get me enthused about tornado potential 

Gotta be able to anticipate how things are going to evolve. The atmosphere isn't static.

[jojo762]

Today reminds me a lot of 5/23/16 with the supercell that went off near Woodward. Triple point is in the same area, winds will back late... just have to be patient. 

Too bad tomorrow won't be like 5/24/16... That was a great day. 

[jojo762]

 Mesoscale Discussion 0495
   NWS Storm Prediction Center Norman OK
   0332 PM CDT Sat Apr 15 2017

   Areas affected...Northwest Oklahoma and part of south-central Kansas

   Concerning...Severe potential...Watch likely 

   Valid 152032Z - 152200Z

   Probability of Watch Issuance...80 percent

   SUMMARY...A severe-weather watch will likely be issued in the next
   hour, with tornado being considered as the watch type across
   northwest OK into part of south-central KS.

   DISCUSSION...Trends in visible satellite imagery showed sustained
   and deepening cumulus clouds in vicinity of the dry line from the
   northeast TX Panhandle through far northwest OK into the adjacent
   part of south-central KS (including the counties of Kiowa, Clark,
   and Comanche).  Surface temperatures near 80 F and into the 80s in
   the TX Panhandle have aided in weakening surface-based inhibition,
   while steepening deep-layer lapse rates and strong instability (up
   to 2500-3000 J/kg) will support storm development this afternoon in
   the discussion area.  This combined with effective bulk shear of
   35-40 kt and strengthening southerly low-level winds into the early
   evening, enhancing hodograph curvature, will favor supercells with
   large hail and a tornado threat.

   ..Peters/Thompson.. 04/15/2017

[Jim Martin]

Severe Weather Watch to be issued. Consideration being given to it possibly being a Tornado Watch.

[Jim Martin]

Mid 60s dewpoints already getting into the far eastern Texas Panhandle and western Oklahoma.

[Jim Martin]