Jump to content
  • Member Statistics

    17,502
    Total Members
    7,904
    Most Online
    Weathernoob335
    Newest Member
    Weathernoob335
    Joined

Severe Weather October 10th-12th 2021


Sydney Claridge
 Share

Recommended Posts

Might as well start a thread for this event.  We have a moderate risk, with a 15% hatched tornado probability across central Oklahoma.

spccoday1.tornado.latest.png

spccoday1.categorical.latest.png

 

Quote
SPC AC 100559

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1259 AM CDT Sun Oct 10 2021

   Valid 101200Z - 111200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST
   THROUGH CENTRAL AND EASTERN OKLAHOMA...

   ...SUMMARY...
   A potentially significant severe weather event is forecast across a
   portion of Oklahoma into north Texas late this afternoon into the
   overnight. Severe storms capable of large to very large hail, a few
   strong tornadoes and damaging wind are expected.

   ...Southern Plains area...

   A vigorous shortwave trough situated near the Four Corners region
   will advance east through the southern Plains this afternoon and
   evening before reaching the lower to mid-MS Valley late tonight. In
   advance of this feature, a cold front now over the central Plains
   will move slowly south. By late afternoon this front will extend
   from a weak surface low in the southeast TX Panhandle or northwest
   TX, northeast through north central OK, southeast KS and northwest
   MO. This boundary will move slowly south into the evening. A dryline
   will extend southward from the surface low through west TX, but will
   eventually be overtaken by a Pacific cold front accompanying the
   progressive shortwave trough.

   Richer low-level moisture return is already underway with mid 60s F
   dewpoints approaching central TX. As temperatures warm through the
   80s F along with modest mid-level lapse rates, up to 1500-2000 J/kg
   MLCAPE is likely by late afternoon. Initial storms should initiate
   over southwest OK or northwest TX along intersection of the dryline
   and the southwest-northeast oriented cold front. Given strength of
   effective bulk shear with 50+ kt associated with the approaching
   mid-upper jet, this activity should quickly become supercellular.
   Hodograph size should undergo a substantial increase as the
   low-level jet strengthens during the early evening with 0-1 km
   storm-relative helicity likely exceeding 250 m2/s2 by 00Z. Given the
   favorable kinematic and thermodynamic parameter space, potential
   exists for a couple of long track supercells to evolve and track
   east northeast through OK along and just south of the front. These
   storms will be capable of producing very large hail and strong
   tornadoes. Additional storms will likely develop farther northeast
   along this front as well farther south into TX as the Pacific front
   intercepts greater low-level moisture. These storms will also likely
   become supercells capable of all hazards. Eventually, storms may
   evolve into lines and clusters during the evening and into the
   overnight, but with a continued severe threat toward the lower and
   middle MS Valley regions.

   ...Upper Mississippi Valley and Great Lakes regions...

   A northern-stream shortwave trough will advance slowly northeast
   through northern MN during the day. Storms may increase over
   northeast MN just northeast of the vorticity maximum during the
   afternoon where wind profiles and modest instability will be
   sufficient for supercells. Primary threat with this activity will be
   hail and possibly a couple of brief tornadoes. Farther southeast
   across WI within the dry slot region, the extent of thunderstorm
   initiation during the day remains uncertain, but a conditionally
   favorable environment for supercells will exist. If confidence
   increases that robust updrafts can develop in this environment, then
   a categorical risk upgrade may be needed in later day 1 updates.

   ..Dial/Marsh.. 10/10/2021

 

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

  • Sydney Claridge changed the title to Severe Weather October 10th-12th 2021

Latest mesoscale model runs have been very concerning and have trended towards more discrete activity in Oklahoma, notably threatening the Norman/Moore/OKC area and even up into Tulsa later on tonight. Latest SPC outlook expands the moderate risk to the north, putting the mentioned cities deeper within the 15% hatched tornado contour. In addition, DFW has now been included in the 10% tornado contour.

1613256347_ScreenShot2021-10-10at12_47_33PM.thumb.png.3dc39f50682e24da279f8d966898771c.png

Link to comment
Share on other sites

2 minutes ago, SmokeEater said:

Tornado watch just issued, 90/70 tornado probs.

Sent from my SM-G973U using Tapatalk
 

SEL7

   URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 517
   NWS Storm Prediction Center Norman OK
   320 PM CDT Sun Oct 10 2021

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     Much of Central and Southwest Oklahoma
     Western North Texas

   * Effective this Sunday afternoon and evening from 320 PM until
     1000 PM CDT.

   * Primary threats include...
     Several tornadoes and a couple intense tornadoes likely
     Widespread damaging winds and isolated significant gusts to 85
       mph likely
     Scattered large hail and isolated very large hail events to 2.5
       inches in diameter likely

   SUMMARY...Severe thunderstorms are expected to rapidly develop this
   afternoon over southwest Oklahoma and race northeastward across the
   watch area.  Supercells capable of strong tornadoes and significant
   wind damage are possible - especially along the I-44 corridor.

   The tornado watch area is approximately along and 70 statute miles
   north and south of a line from 50 miles west southwest of Altus OK
   to 40 miles northeast of Chandler OK. For a complete depiction of
   the watch see the associated watch outline update (WOUS64 KWNS
   WOU7).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A Tornado Watch means conditions are favorable for
   tornadoes and severe thunderstorms in and close to the watch
   area. Persons in these areas should be on the lookout for
   threatening weather conditions and listen for later statements
   and possible warnings.

   &&

   OTHER WATCH INFORMATION...CONTINUE...WW 516...

   AVIATION...Tornadoes and a few severe thunderstorms with hail
   surface and aloft to 2.5 inches. Extreme turbulence and surface wind
   gusts to 75 knots. A few cumulonimbi with maximum tops to 500. Mean
   storm motion vector 25040.

   ...Hart
Link to comment
Share on other sites

15 minutes ago, OhioWX said:

Special 20z OUN sounding. Once that cap erodes...

FBXbLvkXEAUZSrO.thumb.jpg.8ae5e638887e83d2d572fc57182b4076.jpg

A lot to erode in that sounding.  Particularly, -170 J/kg of MLCIN is pretty prohibitive.  This is quite a bit higher that CAM progs at the same time.  I suspect we might have trouble getting CI anywhere away from the front/triple point.

  • Like 2
Link to comment
Share on other sites

2 minutes ago, Powerball said:

It seems the problem is that dewpoints are now starting to mix out. They've fallen into the mid 60s here.

I doubt this will have much of an effect on things.  The really shallow high Td layer near the surface would "mix out" anyway as air parcels ascend through the boundary layer into updrafts.  What really matters is the average PBL moisture.

Link to comment
Share on other sites

Mesoscale Discussion 1822
   NWS Storm Prediction Center Norman OK
   0425 PM CDT Sun Oct 10 2021

   Areas affected...Southwest Oklahoma into western North Texas

   Concerning...Tornado Watch 517...

   Valid 102125Z - 102300Z

   The severe weather threat for Tornado Watch 517 continues.

   SUMMARY...Initiation of discrete storms is becoming more likely in
   the vicinity of Frederick, OK within the next 1-1.5 hours. The
   threat for tornadoes is increasing in southwest Oklahoma into parts
   of central Oklahoma.

   DISCUSSION...Towering cumulus continues to develop south of
   Frederick, OK. The strongest pressure falls in the last few hours
   have occurred in this vicinity. Confidence is increasing in storm
   initiation within the next 1-1.5 hours. Given the backed surface
   winds and over 50 kts of effective shear, initial storm mode will
   likely be supercellular. KFDR VWP has begun to show an increase in
   low-level SRH recently as well. Storms that form in this region
   would pose the greatest tornado risk over the next few hours.

   ..Wendt.. 10/10/2021

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...OUN...

   LAT...LON   33819849 33849879 33949902 34059910 34529892 34989844
               35259790 35289751 35069737 34389761 33819849 
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...