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Severe Weather 4-25 through 4-28-24


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Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0104 AM CDT Sat Apr 27 2024

   Valid 271200Z - 281200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   NORTH TEXAS...OKLAHOMA...SOUTHEAST KANSAS AND FAR SOUTHWEST
   MISSOURI...

   ...SUMMARY...
   Numerous severe thunderstorms are likely today and tonight across
   the southern and central Plains into the lower to mid Missouri
   Valley. The greatest potential for severe storms will be from north
   Texas into Oklahoma and southeast Kansas, where strong tornadoes,
   very large hail over 2 inches in diameter and widespread damaging
   winds (some over 70 mph), are expected to occur. A broader area of
   severe threat will extend from south-central Texas
   north-northeastward to the Great Lakes.

   ...Tornado Outbreak Expected Today From North Texas into
   Oklahoma...Southeast Kansas and Far Southwest Missouri...

   ...Southern Plains...
   An upper-level trough will move through the Desert Southwest today
   as an 80 to 90 knot mid-level jet translates quickly eastward
   through the base of the system. Ahead of the trough, a moist and
   unstable airmass will be in place across much of the southern and
   central Plains. At the surface, a low will move eastward across
   southwest Kansas with a dryline extending southward through far
   western Oklahoma and west Texas. Surface dewpoints to the east of
   the dryline will be in the mid to upper 60s F. In response to warm
   advection this morning, a cluster of thunderstorms is expected to
   develop to the east of the dryline across northwest Texas. This
   cluster is forecast to spread north-northeastward into western
   Oklahoma by late morning. Large hail and wind damage will be likely
   with the stronger cells within this cluster. An outflow boundary
   with this convection should setup across west-central Oklahoma by
   early afternoon, with a moist and unstable airmass extending
   eastward from the boundary across much of central and eastern
   Oklahoma northward into southeast Kansas. This undisturbed airmass
   is expected to be favored for the greatest severe threat this
   afternoon and evening.

   The mid-level jet is forecast to eject quickly northeastward across
   the southern Plains this afternoon. This will result in strong
   deep-layer shear across most of the southern Plains, and will create
   a large-scale mass response that will be very favorable for severe
   storms, including supercells and bowing line segments. As the core
   of the mid-level jet moves into the southern Plains during the mid
   to late afternoon, a 50 to 60 knot low-level jet will rapidly
   strengthen. RAP forecast sounding along and near the low-level jet
   during the late afternoon look very favorable for tornadoes, with
   backed surface flow, and long looping hodographs. As the low-level
   jet strengthens, 0-3 km storm-relative helicity is forecast to
   increase to around 400 m2/s2 across much of central and eastern
   Oklahoma into southeast Missouri. The more dominant and supercells
   that interact with the western and northern edge of the low-level
   jet are expected to become tornadic. Several strong tornadoes will
   be likely, and a few long-track EF3+ tornadoes will be possible.

   In addition to the tornado threat, forecast soundings have 700-500
   mb lapse rates near 8 C/km across much of the warm sector this
   afternoon from north Texas to southeast Kansas. This will be
   favorable for very large hail, with hailstones over 2 inches in
   diameter likely with the more intense storms. Later in the evening,
   a line of severe storms is expected to form, moving eastward across
   eastern Oklahoma and north Texas. Wind gusts over 70 mph will be
   possible with the more intense parts of the line. QLCS tornadoes
   will also be possible with rotating cells embedded in the line late
   this evening into the overnight period.

   ...Central Plains/Lower to Mid Missouri Valley...
   An upper-level low will move through the southern Rockies today, as
   the exit region of a mid-level jet overspreads the central Plains.
   At the surface, a warm front will be located from near a surface low
   in southwest Kansas east-northeastward into the mid Missouri Valley.
   This front will be a focus for convective development this
   afternoon. A band of severe storms is expected to form near the
   front and move northward across northern Kansas into southern
   Nebraska during the early to mid afternoon. RAP forecast soundings
   in northeast Kansas near the front from 18Z to 21Z have MLCAPE near
   3000 J/kg, 0-6 km shear around 60 knots, and steep low to mid-level
   lapse rates. This environment will be very favorable for supercells
   with large hail. Hailstones greater than 2 inches in diameter will
   be possible with the more intense storms. In addition, forecast
   soundings have 0-3 km storm-relative helicity in the 250 to 300
   m2/s2 range, suggesting that tornadoes will be likely with the more
   discrete supercells. A few strong tornadoes will be possible.

   Further west into northwest Kansas and eastern Colorado, cold
   temperatures aloft, strong large-scale ascent associated with an
   upper-level low, and strong deep-layer shear will likely support
   lower-topped supercells with large hail and strong wind gusts this
   afternoon.

   ...Mid to Upper Mississippi Valley/Great Lakes...
   An upper-level trough will move northeastward across the Great Lakes
   region today. From near the trough, and southwestward into the mid
   to upper Mississippi Valley, a wide corridor of moderate instability
   will be in place by afternoon. A warm front will be in located along
   the northern edge of the instability, from Iowa northeastward into
   south-central Wisconsin and north-central lower Michigan. As surface
   heating takes place and low-level convergence increases along the
   front, thunderstorms will likely form in the vicinity of the
   boundary. Forecast soundings near the front at 21Z have MLCAPE
   around 3000 J/kg, along with 40 knots of deep-layer shear. This
   should support supercells with potential for large hail and wind
   damage. The severe threat should be greatest during the late
   afternoon and early evening.
 
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Early morning update:

First Tornado Watch is up for parts of western Oklahoma and the northwest Texas vicinity. The environment is already quite volatile, as it’s not often you have the ingredients come together at 7 AM when the low level jet is still cranking. 

The overnight trends are quite ugly for Oklahoma. Models show less morning convection and any storms that do initiate (well west of I-35) may already have a tornado and hail threat before lunchtime.

By 12 PM, the HRRR shows that the western two thirds of Oklahoma in a very favorable parameter space with minimal capping and lengthy hodographs. You’ll also notice large low level instability. I’m not even seeing much veer back in the forecast wind profiles, that was more glaring in earlier model runs. I hope it’s wrong, but that would favor longer residence time for supercells.

IMG-7540.png

During the afternoon, the consensus is for discrete to semi-discrete storms to rapidly erupt and track east toward central Oklahoma. Now, models do still show mixed and clustered storm modes, which I guess could limit the ceiling slightly. However, with that said, the forecast environment by 21z is higher end for April standards. 3000+ J/kg MLCAPE over a broad area, enlarged, looping hodographs, stronger forcing impinging from the west… it’s a recipe for just a mess of numerous severe thunderstorms.

Yesterday was tough, but today looks like a different kind of challenging. 

Morning: Isolated storm development in an already favorable environment across western Oklahoma. A few isolated supercells can be expected with a hail and tornado threat. 

Early afternoon: Probable development of more intense supercells. All severe hazards apparent, along with an increasing strong tornado threat across the western half of Oklahoma.

Mid to late afternoon: Numerous supercells anticipated, approaching the I-35 corridor. Moderate to extreme instability coupled with enlarging hodographs will support very large hail and strong/intense tornadoes, particularly with any storms that remain at least semi-discrete. 

Into the evening: Widespread severe thunderstorms shift from central toward eastern Oklahoma. Although storm mergers and interactions will likely be underway, the increasing low level jet will continue to support a strong tornado threat. With both line embedded circulations and any storms that manage to remain even just semi-discrete. 

A quick edit to add the 12z OUN sounding. A rich low level moisture profile, beneath a capping inversion. 2600 J/kg MLCAPE at 7 AM. The cap isn’t overly strong, but should preclude any convective initiation near Oklahoma City for at least the next 3-4 hours. 
IMG-7541.jpg

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1300z update hits the tornado threat a little harder with the wording... written by Thompson and Hart

   SPC AC 271256

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0756 AM CDT Sat Apr 27 2024

   Valid 271300Z - 281200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
   FOR OK...NORTH TX...SOUTHEAST KS AND EXTREME SOUTHWEST MO...

   ...SUMMARY...
   Severe thunderstorms are likely today and tonight across the
   southern and central Plains into the lower to mid Missouri Valley.
   The most numerous/intense storms are expected from north Texas into
   Oklahoma and southeast Kansas, where strong tornadoes, very large
   hail of 2-3 inches in diameter and damaging winds of 60-70 mph are
   all possible.

   ...A regional severe-weather outbreak is expected from north TX
   across OK into KS with strong tornadoes, very large hail and
   damaging winds all part of a long-duration threat...

   ...OK/KS/north TX through tonight...
   A pronounced midlevel trough over the Four Corners will move
   eastward today and then begin to eject northeastward tonight over
   the central/southern High Plains.  This synoptic pattern will
   maintain a lee cyclone in southeast CO and a dryline arcing
   southeastward and then southward close to the western OK border. 
   Farther north, a stalling baroclinic zone will move slowly northward
   into northern KS today and central IA by this evening.
   A broad, unstable warm sector with boundary-layer dewpoints of 65-70
   F will support multiple rounds of severe/tornadic storms through the
   period, both along the synoptic boundaries and in parts of the open
   warm sector for OK/KS.

   The initial severe/tornado threat has already begun near Caprock
   from Lubbock to Childress as an embedded jet streak (evident as the
   fast-moving cloud streak over west TX) begins to interact with the
   northwest edge of the richer low-level moisture.  Despite the
   unusually early start, there will be the potential for embedded
   supercells capable of all hazards as the storms overspread
   western/northern OK into southern KS through midday.  An outflow
   boundary and/or differential heating corridor is likely in the
   immediate wake of these morning storms from southern KS into north
   central and southwest OK.  Additional thunderstorm development is
   likely by early-mid afternoon along this zone and the dryline to the
   south into TX, and storms will spread generally northeastward toward
   southern/central OK and southeast KS.  A moist boundary layer,
   MLCAPE of 2500-3500 J/kg and lengthening/enlarging hodographs with
   time (as a mass response to the approaching shortwave trough) will
   become more favorable for tornadic supercells, including the
   potential for long-track EF2-EF3+ tornadoes.  The significant
   tornado threat will be greatest if semi-discrete supercells can be
   maintained well into the afternoon/evening.  Very large hail up to 3
   inches in diameter can also be expected with the more intense
   supercells.

   The storm evolution has the potential to be a bit messy with
   multiple training/conjoined supercells, posing a relatively
   long-duration and repeat threat to areas within the training storm
   corridors across the central third of OK.  Damaging winds will
   become more probable with storm clustering, and there will likely be
   upscale growth into a larger QLCS this evening into tonight as the
   primary shortwave trough approaches from the west.  The potential
   for tornadoes with embedded circulation will continue into the
   overnight hours, along with damaging winds.

   ...East central CO/far western KS this afternoon/evening...
   Near the lee cyclone and a stalled front, thunderstorm development
   is expected by early afternoon in a small cluster/arc across east
   central CO.  Despite boundary-layer dewpoints only in the 40s, cold
   midlevel temperatures and steep lapse rates will contribute to
   surface-based CAPE up to 1000 J/kg.  Relatively large, curved
   hodographs will favor supercells capable of producing a few
   tornadoes and large hail, as well as damaging gusts once any upscale
   growth into a line segment occurs.
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Seeing a wide difference between the NAM/WRF/NSSL guidance and HRRR/RRFS from 12z. 

The former camp erupts a line of convection very quickly across northwest Texas, plowing into central Oklahoma with a mostly linear storm mode. 

On the other hand, the HRRR and RRFS runs continue to show discrete/semi discrete storm modes through at least early afternoon. That’s an obviously much more alarming scenario. 

Radar/satellite trends seem to favor more of the discrete mode with less storms through the morning. However, mesoanalysis shows minimal convective inhibition remaining across the NW Texas vicinity. 

Any way you slice it, today still has a very high ceiling. Even if only a couple of isolated storms reach their full potential. If storm modes do stay more discrete, it’s not going to be a good day. 

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4000+ SBCAPE along the OK/KS border. Latest guidance showing a string of pearls. Supercells maintain separation and intensify as they enter into the Moderate Risk hatched area. 
 

Nadocast really starting to go bonkers. Will be interesting to see what the NWS SPC does at next outlook.

IMG_5508.jpeg

IMG_5510.jpeg

IMG_5509.png

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2 minutes ago, Ed, snow and hurricane fan said:

MCD mentions possible PDS watched by 18Z.  

 

Mesoscale Discussion 0539
   NWS Storm Prediction Center Norman OK
   1057 AM CDT Sat Apr 27 2024

   Areas affected...Northwest TX...western/northern OK...and southeast
   KS

   Concerning...Tornado Watch 144...

   Valid 271557Z - 271730Z

   The severe weather threat for Tornado Watch 144 continues.

   SUMMARY...Severe threat will further increase into the afternoon
   from parts of northwest Texas into southeast Kansas, including
   potential for a couple strong tornadic supercells. A broader tornado
   and/or multiple PDS/non-PDS tornado watches will be needed prior to
   the 18Z expiration of WW 144.

   DISCUSSION...Surface analysis placed the nearly stationary dryline
   across the eastern TX Panhandle through northwest TX. The deepest
   convection is ahead of the dryline in west-central to north-central
   OK, which includes a supercell in cluster and a downstream discrete
   supercell. Surface warming has been more pronounced in parts of
   central OK, generally along and east of the I-35 corridor. The
   leading discrete supercell should have relatively uninterrupted
   inflow as it impinges on this relatively max in boundary-layer
   warming. Amid a 45-kt southerly low-level jet per the TLX VWP data,
   potential will exist for cyclic tornadoes that may be strong. Strong
   mid-level rotation has also been noted with the supercell in cluster
   now centered in Dewey County, OK, and this storm should pose a
   continued threat for all hazards. 

   Additional storms should regenerate along the dryline farther south
   into northwest TX through the afternoon given minimal MLCIN. With
   weaker forcing for ascent relative to farther north, there is some
   uncertainty in how quickly this activity will become severe. But the
   overall environment will favor discrete supercell development,
   especially as the boundary layer further warms.

   ..Grams.. 04/27/2024

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

   ATTN...WFO...TSA...ICT...OUN...SJT...LUB...AMA...
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 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1125 AM CDT Sat Apr 27 2024

   Valid 271630Z - 281200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
   AND EVENING ACROSS PORTIONS OF SOUTHERN KANSAS...MUCH OF
   OKLAHOMA...AND NORTHWEST TEXAS....

   ...SUMMARY...
   Severe thunderstorms are likely today and tonight across the
   southern and central Plains into the lower to mid Missouri Valley.
   The most numerous/intense storms are expected from north Texas into
   Oklahoma and southeast Kansas, where strong tornadoes, very large
   hail of 2-3 inches in diameter and damaging winds of 60-80 mph are
   all possible.

   ...A regional outbreak of severe thunderstorms is forecast for this
   afternoon and evening across parts of KS/OK.  Very large hail and
   strong tornadoes are possible..

   ...OK/northwest TX/south-central KS...
   Water vapor imagery shows the main upper trough is still back over
   southern AZ, with a rapidly ejecting mid/upper level jet streak
   nosing into OK/TX.  This lead feature has aided in the development
   of severe storms this morning over parts of west TX/OK.  Storms will
   develop northeastward through the afternoon into central KS, despite
   an expansive anvil shield from the morning convection.  These storms
   will pose a risk of very large hail and a few tornadoes through the
   afternoon and early evening.

   Farther south, the air mass across much of central/western OK and
   northwest TX continues to warm/destabilize as temperatures rise
   through the mid/upper 70s - eliminating CINH.  Only weak upper
   forcing through the afternoon will result in chaotic development of
   discrete supercells in a very strongly sheared and very unstable
   environment.  Forecast soundings show very steep mid-level lapse
   rates, ample low-level moisture, and strong/increasing shear
   profiles through the day.  Details of timing and location are
   nebulous, but those storms that develop will pose a risk of very
   large hail and strong and possibly long-track tornadoes.  The
   stronger large-scale forcing will arrive around/after dark, with a
   greater eastward surge of storms across central OK expected.  This
   activity may organize upscale in bowing segments will an increasing
   risk of damaging winds along with hail and tornadoes into southeast
   KS and northeast OK tonight.

   ...Southeast CO into northern KS...
   A rather strong surface boundary extends from southeast CO across
   much of northern KS.  Relatively strong heating along this boundary
   and moderate instability will lead to scattered thunderstorm
   development by mid-afternoon along the entire corridor.  Steep
   mid-level lapse rates, strong deep-layer shear, and favorable
   low-level wind profiles in vicinity of the boundary will pose a risk
   of very large hail and a few tornadoes through the afternoon and
   early evening.  This activity is expected to build eastward this
   evening along the same boundary into parts of southern IA/northern
   MO, with a continued risk of large hail along with an increasing
   threat of damaging winds.

   ..Hart/Jewell.. 04/27/2024
 
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Regular (non PDS) tornado watch just went up in KS/NE

URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 145
   NWS Storm Prediction Center Norman OK
   1150 AM CDT Sat Apr 27 2024

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     Central and Northeast Kansas
     Southeast Nebraska

   * Effective this Saturday morning and evening from 1150 AM until
     700 PM CDT.

   * Primary threats include...
     A few tornadoes and a couple intense tornadoes likely
     Widespread large hail and scattered very large hail events to
       2.5 inches in diameter likely
     Scattered damaging winds likely with isolated significant gusts
       to 75 mph possible

   SUMMARY...Thunderstorms will develop across parts of central and
   northeast Kansas through the afternoon in a very moist and unstable
   environment.  The strongest cells will be supercells capable of very
   large hail and tornadoes.  A few strong tornadoes are possible.

   The tornado watch area is approximately along and 80 statute miles
   east and west of a line from 70 miles west northwest of Saint Joseph
   MO to 25 miles southeast of Medicine Lodge KS. For a complete
   depiction of the watch see the associated watch outline update
   (WOUS64 KWNS WOU5).
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13 minutes ago, Ed, snow and hurricane fan said:

Time to see if Ryan Hall is livestreaming chasers. 

IIRC, he said that he had access to 30 chaser feeds, so should be pretty good coverage of the storms

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Severe Weather Statement
National Weather Service Wichita KS
333 PM CDT Sat Apr 27 2024

KSC019-035-049-272115-
/O.CON.KICT.TO.W.0014.000000T0000Z-240427T2115Z/
Elk KS-Cowley KS-Chautauqua KS-
333 PM CDT Sat Apr 27 2024

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 415 PM CDT FOR
SOUTHWESTERN ELK...EASTERN COWLEY AND NORTHWESTERN CHAUTAUQUA
COUNTIES...

At 333 PM CDT, a confirmed large and extremely dangerous tornado was
located over Dexter, or 13 miles west of Cedar Vale, moving northeast
at 30 mph.

This is a PARTICULARLY DANGEROUS SITUATION. TAKE COVER NOW!

HAZARD...Damaging tornado.

SOURCE...Emergency management confirmed tornado.

IMPACT...You are in a life-threatening situation. Flying debris may
         be deadly to those caught without shelter. Mobile homes
         will be destroyed. Considerable damage to homes,
         businesses, and vehicles is likely and complete destruction
         is possible.

This tornadic thunderstorm will remain over mainly rural areas of
southwestern Elk, eastern Cowley and northwestern Chautauqua
Counties, including the following locations... Cambridge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a large, extremely dangerous and potentially deadly
tornado is on the ground. To protect your life, TAKE COVER NOW! Move
to a basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 3709 9672 3717 9685 3745 9662 3729 9639
TIME...MOT...LOC 2033Z 209DEG 25KT 3716 9673

TORNADO...OBSERVED
TORNADO DAMAGE THREAT...CONSIDERABLE
MAX HAIL SIZE...1.00 IN

$$
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Severe Weather Statement
National Weather Service Norman OK
330 PM CDT Sat Apr 27 2024

OKC103-272100-
/O.CON.KOUN.TO.W.0025.000000T0000Z-240427T2100Z/
Noble OK-
330 PM CDT Sat Apr 27 2024

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 400 PM CDT FOR EASTERN
NOBLE COUNTY...

At 330 PM CDT, a confirmed tornado was located 4 miles west of
Morrison, moving north at 45 mph.

HAZARD...Damaging tornado and quarter size hail.

SOURCE...Weather spotters confirmed tornado.

IMPACT...Flying debris will be dangerous to those caught without
         shelter. Mobile homes will be damaged or destroyed. Damage
         to roofs, windows, and vehicles will occur.  Tree damage is
         likely.

Locations impacted include...
Morrison and Sooner Lake.
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TXC023-275-272130-
/O.NEW.KOUN.TO.W.0027.240427T2041Z-240427T2130Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Norman OK
341 PM CDT Sat Apr 27 2024

The National Weather Service in Norman has issued a

* Tornado Warning for...
  Southeastern Knox County in northern Texas...
  Southwestern Baylor County in northern Texas...

* Until 430 PM CDT.

* At 341 PM CDT, a large and extremely dangerous tornado was located
  near Rhineland, moving northeast at 25 mph.

  This is a PARTICULARLY DANGEROUS SITUATION. TAKE COVER NOW!

  HAZARD...Damaging tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...You are in a life-threatening situation. Flying debris
           may be deadly to those caught without shelter. Mobile
           homes will be destroyed. Considerable damage to homes,
           businesses, and vehicles is likely and complete
           destruction is possible.

* Locations impacted include...
  Seymour, Munday, Goree, Red Springs, Vera, Rhineland, and Bomarton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, an extremely dangerous and potentially deadly tornado is
on the ground. To protect your life, TAKE COVER NOW! Move to a storm
shelter, safe room or an interior room on the lowest floor of a
sturdy building. Avoid windows. If you are outdoors, in a mobile
home, or in a vehicle, move to the closest substantial shelter and
protect yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 3358 9977 3375 9951 3372 9936 3360 9928
      3349 9935 3346 9957 3345 9972
TIME...MOT...LOC 2041Z 206DEG 20KT 3354 9969

TORNADO...RADAR INDICATED
TORNADO DAMAGE THREAT...CONSIDERABLE
MAX HAIL SIZE...2.75 IN
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