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Plains tornado threat Mon 5/27-Fri 5/31


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That convective complex is impinging well into Oklahoma now. The "shallow warm frontal feature" mentioned in SPC's 13Z Day1, and by others here, seems likely to merge with the outflow from that complex and become not-so-shallow. Indeed, the Oklahoma Mesonet is now showing a 15-degree temperature gradient across the span of only about 30 miles (Blackwell to Red Rock). I wonder whether that outflow will end up shoving the area of greatest helicities a bit farther south toward the metro than earlier anticipated.

 

Yeah, I think the northern one-third of the hatched area is out of play now.  I would expect the SPC to reflect this with their next update.

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That convective complex is impinging well into Oklahoma now. The "shallow warm frontal feature" mentioned in SPC's 13Z Day1, and by others here, seems likely to merge with the outflow from that complex and become not-so-shallow. Indeed, the Oklahoma Mesonet is now showing a 15-degree temperature gradient across the span of only about 30 miles (Blackwell to Red Rock). I wonder whether that outflow will end up shoving the area of greatest helicities a bit farther south toward the metro than earlier anticipated.

 

 

The OUN 7 am sounding already has crazy low level shear, and pretty impressive early morning instability despite a 700 mb warm nose. 

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The OUN 7 am sounding already has crazy low level shear, and pretty impressive early morning instability despite a 700 mb warm nose.

If you took away that cap at 700, todays potential would be screwed by an explosion of morning convection. Need that warm nose

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Yeah, I think the northern one-third of the hatched area is out of play now.  I would expect the SPC to reflect this with their next update.

Yea, I wouldn't be surprised to see the hatched area trimmed back to the state line or perhaps a Ponca, to Nowata to Vanita line.

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The current and progged environment (NAM/RAP/GFS) over cntl/ern OK today and tonight are just unbelievable.  I think it's probably the most impressive environment we've had all year.  The number of storms will certainly be limited by the forcing, but a lone storm in this environment is going to have almost unlimited potential.

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The current and progged environment (NAM/RAP/GFS) over cntl/ern OK today and tonight are just unbelievable.  I think it's probably the most impressive environment we've had all year.  The number of storms will certainly be limited by the forcing, but a lone storm in this environment is going to have almost unlimited potential.

Any thoughts on how this ongoing convection will limit storms in the northern part of the MDT area?  We've got friends/family in Bville and most of them aren't too weather aware.  At this point I'm thinking (as already mentioend) that the ongoing convection moving across the state line and vicinity will put a damper on the tor potential up that far north....hope I'm right.

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Any thoughts on how this ongoing convection will limit storms in the northern part of the MDT area?  We've got friends/family in Bville and most of them aren't too weather aware.  At this point I'm thinking (as already mentioend) that the ongoing convection moving across the state line and vicinity will put a damper on the tor potential up that far north....hope I'm right.

The biggest threat is clearly south of the state line and probably south of a Vinita-Ponca City line.

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The biggest threat is clearly south of the state line and probably south of a Vinita-Ponca City line.

Thank you sir, that is in lock step with what I told them about 45 mins ago, we'll see what SPC says and how things unfold the next few hours.

 

To those chasing today be safe...I'll probably be out tomorrow.

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Wednesday is history. Today is a whole new regime, mainly a strong jet max punching in aloft. Outflow boundary appears to finally be slowing down. I could see two targets for two different reasons today/Thursday. Friday has big potential as well if things align.

 

Thursday/today: Strong jet max is somewhat straight; therefore, one might analyze the four quadrants. Oklahoma is in a "wrong" quad for enhanced lift. Also got subsidence behind morning wave. On the other hand if it behaves like a curved jet max then OK will light up big and bad. Instability is insane; one "needs" some of that subsidence early to reload the gun; and, low level directional shear will be crazy. The question is between: Right on the OFB closer to middle of jet max; or, first supercell south of OFB on DL for the more isolated play. OFB has shear but risk of cool pool. DL has instability but risk of wrong jet quad. Given slight UVV on models into all of Oklahoma, I slightly lean DL. One might hedge north though. Typically easier to correct south than to chase north.

 

Friday: High-res models not really showing much south of a tail-end charlie. However the GFS op is showing isolated light precip south of line, into south-southwest Oklahoma. First jet exiting with new coming in. It's very subtle, but could get kissing jets over OK. Right rear (right entrance) of lead jet is upward motion. Next one coming in behind is curved, so it would definitely be lift. Lower level wind fields respond with little better surface low in OK on Friday. There is a path to Friday being the biggest day, but right now both appear excellent for chasers. Latest high-res guidance spares OKC metro isolated beast sup today, which is good news.

 

Unlike last week, I can't get out there this time. However I'll be forecasting. Good luck and be safe!

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The current and progged environment (NAM/RAP/GFS) over cntl/ern OK today and tonight are just unbelievable.  I think it's probably the most impressive environment we've had all year.  The number of storms will certainly be limited by the forcing, but a lone storm in this environment is going to have almost unlimited potential.

 

I agree the environment is impressive but you think it's the most impressive all year? Besides some of the synoptic-scale features that you mention being a negative (or not if you want to scale out crap-convection), the surface winds are not exactly "backed" yet near the DL/OFB. The new GFS backs them around 00z, possibly a little earlier. Should be interesting, watching the low-level winds and remnant boundaries.

I'm not saying things aren't impressive but I still say 5/19-20 looked more impressive.

 

"@Jeff_Piotrowski Outflow boundary is stalling from Tulsa to Enid, OK intersection dry line just west of Enid expect explosive development after 2pm supercells tornadoes likely."[/size]

 

As the new 1630z suggested, there are still some uncertainties WRT warming mid-levels. Also note the winds have yet to back appreciably anywhere near these intersecting boundaries.

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I never said we couldn't have a threat just commenting on conditions now....obviously if the atmosphere recovers it is game in :)

and I just got out of a meeting and see an MDT up for my area so SPC isn't too concerned it seems...

I have also seen several busts on days like today....not at all saying that is what will happen today.

I will say I am far more concerned with tomorrow.

RAZR 2

 

I see what you mean about tomorrow and I agree it looks nasty. I didn't mean to imply you were lessening the threat. I suppose I misunderstood what you meant by "wrung out." If you were merely suggesting "stability issues" from ongoing convection then I understand. I thought you meant it as "the atmosphere has been so active lately that it may not have anything left in it for today's threat" ... my mistake.

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I agree the environment is impressive but you think it's the most impressive all year? Besides some of the synoptic-scale features that you mention being a negative (or not if you want to scale out crap-convection), the surface winds are not exactly "backed" yet near the DL/OFB. The new GFS backs them around 00z, possibly a little earlier. Should be interesting, watching the low-level winds and remnant boundaries.

I'm not saying things aren't impressive but I still say 5/19-20 looked more impressive.

 

 

As the new 1630z suggested, there are still some uncertainties WRT warming mid-levels. Also note the winds have yet to back appreciably anywhere near these intersecting boundaries.

At this point, 5/20 certainly didn't seem more impressive than today.  I like the progged low-level wind and instability profiles more today than I did for 5/19 and 5/20.

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Tornado Watch coming shortly for SE KS/SW MO/NE OK/NW AR

MESOSCALE DISCUSSION 0877
   NWS STORM PREDICTION CENTER NORMAN OK
   1144 AM CDT THU MAY 30 2013

   AREAS AFFECTED...OZARK PLATEAU

   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 

   VALID 301644Z - 301815Z

   PROBABILITY OF WATCH ISSUANCE...95 PERCENT

   SUMMARY...LINE SEGMENTS/CLUSTERS WILL INTENSIFY THIS AFTERNOON WITH
   ALL SEVERE HAZARDS POSSIBLE. WW WILL BE ISSUED IN THE NEXT HOUR OR
   SO.

   DISCUSSION...REFLECTIVITY GRADIENT ASSOCIATED WITH PERSISTENT MCS
   OVER SERN KS INTO FAR NRN OK HAS BEGUN TO TIGHTEN UP WITH UPDRAFTS
   FORMING ALONG THE CONVECTIVE OUTFLOW. FARTHER SE...MORNING CLUSTERS
   HAVE INCREASED IN BOTH INTENSITY AND COVERAGE ACROSS ERN OK. WITHIN
   A RICHLY MOIST BOUNDARY LAYER AND POCKETS OF GREATER INSOLATION
   YIELDING A MODERATELY UNSTABLE AIR MASS...THESE CONVECTIVE AREAS
   SHOULD FURTHER BLOSSOM DURING THE AFTERNOON. AREA VWP DATA DO DEPICT
   VEER-BACK-VEER DEEP-LAYER WIND PROFILES WHICH SHOULD TEND TO FOSTER
   CONTINUED CLUSTER/LINE MODE. HOWEVER...SUFFICIENTLY STRONG LOW-LEVEL
   SHEAR DOES EXIST TO SUPPORT A RISK FOR A COUPLE OF EMBEDDED
   SUPERCELLS.

   ..GRAMS/MEAD.. 05/30/2013
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The current and progged environment (NAM/RAP/GFS) over cntl/ern OK today and tonight are just unbelievable.  I think it's probably the most impressive environment we've had all year.  The number of storms will certainly be limited by the forcing, but a lone storm in this environment is going to have almost unlimited potential.

 

Not gonna lie, I'm not really impressed with the setup for today, or tomorrow.

 

Disjointed WAA (shear) and CAPE regimes with the available forcing. We'll get storms for sure. But I bet similar to yesterday, that tornado reports are very few, and in fact, even hail reports aren't as notable as are damaging winds. Bet we see more blue on the reports maps again than anything else

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Tornado watch coming for the Metro, says very favorable for discrete supercells.

MESOSCALE DISCUSSION 0878

NWS STORM PREDICTION CENTER NORMAN OK

1220 PM CDT THU MAY 30 2013

AREAS AFFECTED...CNTRL/SRN OK...FAR NWRN TX

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 301720Z - 301945Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...A TORNADO WATCH WILL LIKELY BE ISSUED BY MID-AFTERNOON

WITH THE POTENTIAL FOR A FEW DISCRETE SUPERCELLS CAPABLE OF

PRODUCING VERY LARGE HAIL AND A COUPLE OF STRONG TORNADOES.

DISCUSSION...TCU/CB HAS PERSISTED ALONG THE INTERSECTION OF THE

EFFECTIVE DRYLINE AND LOW-LEVEL THERMAL AXIS. DESPITE FOCUS FOR

LARGER-SCALE ASCENT SHIFTING NEWD/TENDENCY FOR MID-LEVEL

TEMPERATURES TO WARM THIS AFTERNOON...CONTINUED HEATING OF A VERY

RICHLY BUOYANT AIR MASS SHOULD RESULT IN SUSTENANCE OF INTENSIFYING

UPDRAFTS ALONG THE DRYLINE AND PERHAPS THE REMNANT OUTFLOW BOUNDARY

ACROSS N-CNTRL OK. WITH AN ENLARGED HODOGRAPH EVIDENT IN THE PURCELL

PROFILER...CHARACTERIZED BY STRONG LOW-LEVEL SHEAR AND SUBSTANTIAL

VEERING OF THE WIND PROFILE INTO THE MID-LEVELS...SETUP WILL BE

HIGHLY FAVORABLE FOR DISCRETE SUPERCELLS.

..GRAMS/MEAD.. 05/30/2013

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Not gonna lie, I'm not really impressed with the setup for today, or tomorrow.

 

Disjointed WAA (shear) and CAPE regimes with the available forcing. We'll get storms for sure. But I bet similar to yesterday, that tornado reports are very few, and in fact, even hail reports aren't as notable as are damaging winds. Bet we see more blue on the reports maps again than anything else

 

My windshield disagrees with the lack of hail reports yesterday. The reason you didn't get many hail reports was because most chasers stayed out of the hail. I ended up coring a storm that radar estimated had 1.5" hail and ended up getting a baseball to the windshield. Just saying, don't underestimate the hail. I bet ya if those cells were in more populated areas, you would have had many more hail reports.

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Early initiation on the dryline again, ala 5/20. Climatologically, that isn't favorable for a major event in this part of the country. But, with rich moisture and high instability already in place, climatology could once again be defied.

 

Mesonet currently depicts an area of localized backing of sfc winds -- wouldn't you know it -- around Cleveland/McClain Co.

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