Severe Weather May 3rd 2021

[Powerball]

3 minutes ago, TexMexWx said:

Woah wait a 10% sigtor countour in the latest outlook just barely northeast of here

EDIT: We're in or close to being in all sig severe hazards here in the Metroplex.

Actually, all of the Collin County suburbs (Plano, Frisco, McKinney, Allen, etc.) are in the 10% hatched SigTor area. 

[WhirlingWx]

/s

[WhirlingWx]

1 minute ago, Powerball said:

Actually, all of the Collin County suburbs (Plano, Frisco, McKinney, Allen, etc.) are in the 10% hatched SigTor area. 

You're right, now with the updated map on SPC I see that the 10% hatched is like maybe 10 miles north/northwest of me lol

[janetjanet998]

[weatherextreme]

Looks like the SPC is not out right sold on sig tornadoes with this setup, but is mentioning as more a possibility.

 

 

Given rich boundary-layer moisture coupled with the large MLCAPE,
   there is concern for at least conditional significant tornado
   potential across a portion of north TX into southeast OK. If upscale
   growth occurs too quickly, this may not be realized, but have
   highlighted a corridor of enhanced tornado potential in this region.
   Otherwise, upscale growth will occur at some point this evening
   rendering a predominant severe wind threat spreading east-northeast
   towards the Mid-South through tonight.

[WhirlingWx]

Yeah it's a conditional threat with multiple things that can work against it, but the potential is there to point it out. Plus, with as much CAPE as we are forecasted to have, weird mesoscale accidents happen.

[Powerball]

16 minutes ago, weatherextreme said:

Looks like the SPC is not out right sold on sig tornadoes with this setup, but is mentioning as more a possibility.

 

 

Given rich boundary-layer moisture coupled with the large MLCAPE,
   there is concern for at least conditional significant tornado
   potential across a portion of north TX into southeast OK. If upscale
   growth occurs too quickly, this may not be realized, but have
   highlighted a corridor of enhanced tornado potential in this region.
   Otherwise, upscale growth will occur at some point this evening
   rendering a predominant severe wind threat spreading east-northeast
   towards the Mid-South through tonight.

I'm not impressed with the tornado threat frankly, with the veered wind profile above 925mb and the (relatively) limited low-level shear.

The hail threat is legit though, as well as the potential for downburst winds. 

[WhirlingWx]

I just stepped outside for the first time today (lol) and it feels the soupiest it's been all year. Full sunshine too.

[weatherextreme]

 

[weatherextreme]

 

[SluggerWx]

Holy 12z HRRR helicity swaths for NW/northern TX this afternoon...
 
 

There's another 200 mile swath showing up on the NSSL that tracks from Odessa all the way to the western outskirts of DFW metroplex starting around 6-7pm tonight thru tomorrow morning.

Sent from my Pixel 3 XL using Tapatalk

[SluggerWx]

There's another 200 mile swath showing up on the NSSL that tracks from Odessa all the way to the western outskirts of DFW metroplex starting around 6-7pm tonight thru tomorrow morning.

Sent from my Pixel 3 XL using Tapatalk

Actually, these mega swaths are more apparent on the last few runs of the HRRR (like you posted). Kind of alarming to see the same tracks show up on the 12z, 13z, 14z, 15z and 16z run.

It seems like normally there's deviation across 5 runs, but these mega swaths are there for 5 straight runs!

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[cheese007]

Well I guess SPC was onto something with the original threat area after all!

[WhirlingWx]

These southeast US 5% risks keep producing tornadoes, which frankly doesn't impact our risk much but these systems sure seem to want to drop 'em.

Shear is still pretty weak here though and I don't think that's expected to change much on a large scale (obviously this is more in reference to the tornado threat in particular).

[Powerball]

000
FXUS64 KFWD 031832
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
132 PM CDT Mon May 3 2021

...New Short Term, Aviation...

.SHORT TERM... /NEW/
/Today and Tonight/

Severe thunderstorms capable of producing significant large hail,
damaging winds, and tornadoes will be possible late this
afternoon into tonight. All North and Central Texas residents need
to stay weather aware today given the possibility of significant
severe weather. Make sure to have multiple ways of receiving any
weather alerts, and have a plan in case you are in the path of
hazardous weather.

A rapid evolution of today and tonight`s forecast has taken place
within the last 24 hours. Minor changes in the timing of the
front and rapid moisture return have contributed to an increasing
potential for significant severe weather starting late this
afternoon. A cold front is now draped northeast to southwest from
near Bowie to Graham, slowly advancing to the southeast.
Meanwhile, dew points throughout the region have surged into the
lower 70s ahead of the front. At the moment, a stout capping
inversion is keeping convection from developing. This, however, is
expected to change in the next few hours. Radiational heating
will continue ahead of the front, leading to greater
destabilization across the region. CAMs continue to favor an area
around Stephenville for initial thunderstorm development, which
coincides with recent RAP analysis of a developing area of greater
moisture convergence.

An incoming shortwave, coupled with the surface front and a
pseudo-dryline will come together to produce explosive
thunderstorm development initially to the west/southwest of the
DFW Metroplex. Storms will then migrate eastward through North
Texas. Steep mid-level lapse rates will lead to CAPE values
exceeding 4000 J/kg which would translate to significantly large
hail. Deep layer shear and a strong southerly low-level flow will
also increase the potential for damaging winds and tornadoes. The
overall tornado potential will depend on the evolution of the
storms across North Texas. If storms are able to remain discrete,
a greater tornado potential may develop in areas east of I-35 and
north of I-30.

An atypical setup this evening will also lead to a potential for
severe storms behind the front. Given continued steep lapse rates
and high amounts of instability, a few elevated supercells capable
of large hail will be possible across North Texas after around
10pm.

The main line of storms associated with the front will continue
moving to the southeast through the night, likely exiting our far
eastern and southeastern counties closer to sunrise Tuesday.
Cloudy skies will persist through much of tomorrow morning, but
should gradually disperse by tomorrow afternoon. In contrast with
today`s temperatures in the upper 80s to lower 90s, tomorrow`s
highs will stay in the 80s across North Texas to mid 70s across
Central Texas.

[WhirlingWx]

That's a very thoughtful discussion by FWD. I really am hoping we dodge a bullet with any significant severe storms, but again, it's conditional days like these that have produced our most noteworthy severe weather events for the past several years. 

I have a ton of work to catch up on, but if I have time and the situation presents itself, there's a park within a couple miles of my house that gives me a slightly elevated perch to look off miles to the west that I could go to for a bit and see if I can view anything.

[weatherextreme]

 

 

 

[yoda]

2000 OTLK maintains 10% sig tor 

[yoda]

STW coming in a few hours sounds like for SE NM and W TX -- https://www.spc.noaa.gov/products/md/md0497.html

 

[StormChazer]

I'll be headed out shortly down to McAlester to see what happens.

[cheese007]

 Mesoscale Discussion 0498
   NWS Storm Prediction Center Norman OK
   0314 PM CDT Mon May 03 2021

   Areas affected...Northern Texas and southeast Oklahoma

   Concerning...Severe potential...Tornado Watch likely 

   Valid 032014Z - 032215Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Strong to severe thunderstorms are expected to develop
   across north Texas and south-central Oklahoma between 5-7 PM CDT.
   These storms will pose a risk for large hail and a few tornadoes. A
   watch is likely by 21 UTC.

   DISCUSSION...Surface observations from north TX and southern OK
   reveal a surface low northeast of Abilene, TX with a stalled cold
   front draped to the southwest and a dryline extending to the south.
   To the northeast of this low, a stationary front is noted across
   southern to northeast OK. Recent GOES visible imagery shows a
   shallow, but growing, cumulus field west of the DFW metro into
   southeast OK east of the stationary boundary. A 19 UTC FWD sounding
   shows considerable MLCIN remains in place, and should keep
   convection at bay in the near term. However, continued diurnal
   heating and increasing ascent over the region (due to the approach
   of an upper-level wave from the west) will help erode lingering
   inhibition by the 5-7 PM CDT time frame. Deep-layer shear is
   forecast to increase as stronger flow associated with the synoptic
   trough moves over the region, which will support initially discrete
   cells along the dryline and stationary boundary. Steep mid-level
   lapse rates noted in the 19 UTC FWD sounding and dewpoints
   increasing into the upper 60s/low 70s will support MLCAPE values
   near 3000-4000 J/kg. 

   Consequently, severe hail appears likely and a few instances of
   large (2+") hail are probable with any initial discrete storms. The
   KFWS VWP recently observed around 100 m2/s2 0-1 km SRH, which may
   support at least a low-end tornado threat across north TX. The
   tornado threat will likely be higher along the Red River and
   northward into south/southeast OK in the vicinity of the triple
   point and along the stationary boundary where more backed low-level
   winds are noted and environmental vertical vorticity is higher.
   Although the potential for a few tornadoes exists with any initial
   discrete convection, rapid upscale growth is possible within an hour
   or two after initiation, and may limit the overall tornado
   potential. Nonetheless, a tornado watch is likely by 21 UTC.

   ..Moore/Grams.. 05/03/2021

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

   ATTN...WFO...SHV...TSA...FWD...OUN...SJT...

   LAT...LON   32349878 33399800 34149751 34849731 35219655 35269553
               34959507 34309498 33569502 32899532 32439620 31919717
               31539805 31409867 31639898 32349878 

[Powerball]

Just now, cheese007 said:

 Mesoscale Discussion 0498
   NWS Storm Prediction Center Norman OK
   0314 PM CDT Mon May 03 2021

   Areas affected...Northern Texas and southeast Oklahoma

   Concerning...Severe potential...Tornado Watch likely 

   Valid 032014Z - 032215Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Strong to severe thunderstorms are expected to develop
   across north Texas and south-central Oklahoma between 5-7 PM CDT.
   These storms will pose a risk for large hail and a few tornadoes. A
   watch is likely by 21 UTC.

   DISCUSSION...Surface observations from north TX and southern OK
   reveal a surface low northeast of Abilene, TX with a stalled cold
   front draped to the southwest and a dryline extending to the south.
   To the northeast of this low, a stationary front is noted across
   southern to northeast OK. Recent GOES visible imagery shows a
   shallow, but growing, cumulus field west of the DFW metro into
   southeast OK east of the stationary boundary. A 19 UTC FWD sounding
   shows considerable MLCIN remains in place, and should keep
   convection at bay in the near term. However, continued diurnal
   heating and increasing ascent over the region (due to the approach
   of an upper-level wave from the west) will help erode lingering
   inhibition by the 5-7 PM CDT time frame. Deep-layer shear is
   forecast to increase as stronger flow associated with the synoptic
   trough moves over the region, which will support initially discrete
   cells along the dryline and stationary boundary. Steep mid-level
   lapse rates noted in the 19 UTC FWD sounding and dewpoints
   increasing into the upper 60s/low 70s will support MLCAPE values
   near 3000-4000 J/kg. 

   Consequently, severe hail appears likely and a few instances of
   large (2+") hail are probable with any initial discrete storms. The
   KFWS VWP recently observed around 100 m2/s2 0-1 km SRH, which may
   support at least a low-end tornado threat across north TX. The
   tornado threat will likely be higher along the Red River and
   northward into south/southeast OK in the vicinity of the triple
   point and along the stationary boundary where more backed low-level
   winds are noted and environmental vertical vorticity is higher.
   Although the potential for a few tornadoes exists with any initial
   discrete convection, rapid upscale growth is possible within an hour
   or two after initiation, and may limit the overall tornado
   potential. Nonetheless, a tornado watch is likely by 21 UTC.

   ..Moore/Grams.. 05/03/2021

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

   ATTN...WFO...SHV...TSA...FWD...OUN...SJT...

   LAT...LON   32349878 33399800 34149751 34849731 35219655 35269553
               34959507 34309498 33569502 32899532 32439620 31919717
               31539805 31409867 31639898 32349878 

[cheese007]

3-4K CAPE is some nasty stuff! 

[Powerball]

Just now, cheese007 said:

3-4K CAPE is some nasty stuff! 

5000 J/KG MUCAPE popping up on the SPC mesoanalysis page now.

Also, LIs of -12

[vwgrrc]

Gosh no. I have an airport pick up at 7-ish. Probably the worst time to show up at DFW... 

Should I stay home for while or arrive there early and hide in the garage?

[Powerball]

You can now start to see what looks to be gravity waves on the visible satellite, and the CU field increasing. This is all on the nose of the 700mb jet streak.

Should start seeing action rev up soon.

[Witness Protection Program]

The lower levels of those massive semi-circle parking garages seem like a good option, especially Terminal D's, since the west side is wrapped and mostly shielded by the terminal.  I'd duck in if the radar looks risky, I bet the parking fee is cheaper than the insurance deductable in America's hail capital.

[StormChazer]

There's the Watch!

[Witness Protection Program]

Is it the dryline or front that is the visible line on the DFW and Abilene radars, stretching from Lake Bridgeport and across the NW tip of Parker County down to Santa Anna, then trails west towards Ballinger?

[vwgrrc]

3 minutes ago, Witness Protection Program said:

The lower levels of those massive semi-circle parking garages seem like a good option, especially Terminal D's, since the west side is wrapped and mostly shielded by the terminal.  I'd duck in if the radar looks risky, I bet the parking fee is cheaper than the insurance deductable in America's hail capital.

haha Thanks so much! I need to watch radar closely from now on.