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

[andyhb]

Kind of a bad place for that in OK

 

Um...yeah that's just not good.

 

FWIW, the NSSL WRF isn't as enthused for tomorrow, but seeing just one of them showing that is concerning enough.

[brettjrob]

This has already been noted widely here and elsewhere, but tomorrow bears an uncanny similarity to the 19 May setup that produced Carney and Norman/Shawnee. At this point, I almost have to expect the metro area will be ground zero for the most significant activity (persistence forecast?), and the 4 km NMM shows exactly that.

[Ian]

This has already been noted widely here and elsewhere, but tomorrow bears an uncanny similarity to the 19 May setup that produced Carney and Norman/Shawnee. At this point, I almost have to expect the metro area will be ground zero for the most significant activity (persistence forecast?), and the 4 km NMM shows exactly that.

Well, if all the chasers hang out around OKC tomorrow maybe it'll happen somewhere else.

[LocoAko]

Kind of a bad place for that in OK

 

 

Ugh... 

[Thundersnow12]

This is just bad. Very bad. I haven't seen a run like this in a long time. Animated GIF of the 0z 4km WRF.

 

http://gifmaker.me/PlayFrameAnimation.php?folder=2013053000NAIAlWa9xeEEI8pscf9MlB

[RCNYILWX]

This is just bad. Very bad. I haven't seen a run like this in a long time. Animated GIF of the 0z 4km WRF.

 

http://gifmaker.me/PlayFrameAnimation.php?folder=2013053000NAIAlWa9xeEEI8pscf9MlB

Even the regular 2-5 km UH is close to maxed out.

Sent from my SCH-I535 using Tapatalk 2

[FSMweather]

Tornado warning near Gore,OK by the Lake Tenkiller area.

[Thundersnow12]

Even the regular 2-5 km UH is close to maxed out.

Sent from my SCH-I535  2

 

You can even see that supercell fire, then throw off a left split and turn. Simply amazing.

 

[brettjrob]

Subjectively, I would say the NSSL WRF has outperformed the SPC 4 km NMM over the past couple weeks, at least the days I've looked at both. So, if one of them is going to show grinders through the metro, I suppose it's the less concerning of the two.

[jcwxguy]

new day 1 remains slight risk however...

 

 

..PLAINS STATES TO UPPER MS VALLEY AND UPPER MIDWEST  
 
PRIMARY CONCERN ATTM IS FOR ISOLATED TO WIDELY SCATTERED TSTMS TO  
DEVELOP INVOF DRYLINE DURING LATE AFTN AFTER STG/SUSTAINED SFC  
HEATING AND MOVE EWD...OFFERING RISK OF VERY LARGE/DAMAGING HAIL AND  
TORNADOES. NARROW SECTOR OF VERY FAVORABLE SUPERCELL-SUPPORTING  
PARAMETER SPACE IS APPARENT FROM ABOUT E-CENTRAL KS SWWD TO RED  
RIVER REGION OF OK AND N TX...FOR ANY TSTMS THAT CAN FORM AND  
PERSIST TO MATURITY. ROBUST MOIST-SECTOR AIR IS FCST AHEAD OF  
DRYLINE...WITH SFC DEW POINTS RANGING FROM MID-60S TO LOW-70S F  
SUPPORTING MLCAPE IN 3000-5000 J/KG RANGE...LYING BENEATH 55-65 KT  
EFFECTIVE SHEAR MAGNITUDES. HODOGRAPHS ARE EXPECTED TO ENLARGE  
CONSIDERABLY IN 00Z-03Z TIME FRAME OVER AREA OF LARGEST HAIL/TORNADO  
PROBABILITIES...AS LLJ STRENGTHENS. UNLIKE PREVIOUS DAY...GEOMETRY  
OF FLOW RELATED TO NEGATIVELY TILTED SHORTWAVE WILL RENDER  
DEEP-SHEAR AND MEAN-WIND VECTORS NEARLY ORTHOGONAL TO  
DRYLINE...INDICATING GREATER POTENTIAL FOR DISCRETE STORM CHARACTER  
AND SUPERCELL MODE.  
 
HOWEVER...SOME CAVEATS ARE EVIDENT THAT MAKE THREAT TOO CONDITIONAL  
TO INTRODUCE MDT-RISK PROBABILITIES YET...AND WHICH ALSO CAST GREAT  
UNCERTAINTY ON SVR POTENTIAL FARTHER N OVER MO VALLEY..NRN PLAINS  
AND CORN BELT. THESE INCLUDE...  
1. ABUNDANT PRIOR AND ONGOING CONVECTION FROM ERN OK/OZARKS AREA NWD  
ACROSS MO VALLEY AND NWWD OVER PORTIONS KS...EARLY IN PERIOD. THIS  
ACTIVITY HAS OVERTURNED AIR MASS ACROSS MUCH OF THAT  
REGION...LOWERING DEW POINTS. RESULTING MODIFIED BOUNDARY LAYER  
WILL ADVECT NWD ACROSS CENTRAL PLAINS...IA...DAKOTAS AND MO VALLEY  
REGION WITH FRAGMENTED AND MODULATED MOISTURE FIELD...CHARACTERIZED  
BY EMBEDDED RIBBONS AND POCKETS OF LOW-THETAE AIR.  
2. LACK OF WELL-DEFINED FOCI FOR INITIATION IN THAT AIR  
MASS...ESPECIALLY FROM ABOUT I-70 NWD.  
3. HEIGHT RISES ARE EXPECTED BEHIND SHORTWAVE TROUGH THROUGHOUT  
AFTERNOON OVER SRN PLAINS...WITH WEAK MID-UPPER LEVEL VERTICAL  
MOTIONS.  
4. CAPPING WILL INHIBIT TSTM COVERAGE...ESPECIALLY FROM RED RIVER  
AREA SWD ACROSS W-CENTRAL/SW TX. ANY TSTM THAT DOES DEVELOP OFF  
DRYLINE OVER TX STILL WILL POSE SVR WIND/HAIL RISK BEFORE NOCTURNAL  
DISSIPATION.  
5. NARROWNESS OF MOST FAVORABLE MOIST SECTOR MAY LIMIT TIME WINDOW  
FOR SUPERCELLS. STILL...GIVEN RECOVERY EXPECTED OVER OK AND  
PROBABLY SERN KS...VERY LARGE CAPE WILL SUPPORT ENHANCED  
TORNADO/HAIL PROBABILITIES FOR NOW WITHIN SLGT-RISK FRAMEWORK.  
 
AS SOME OF THESE UNCERTAINTIES GET BETTER RESOLVED TODAY...NARROW  
AREA OF SIGNIFICANT-TORNADO AND/OR LARGER-HAIL PROBABILITIES MAY  
BECOME NECESSARY...ESPECIALLY OVER PORTIONS OK AND KS.

 

[andyhb]

D2:

 

DAY 2 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   1257 AM CDT THU MAY 30 2013   VALID 311200Z - 011200Z   ...THERE IS A SLGT RISK OF SVR TSTMS FOR OK AND ERN KS NEWD INTO THE   SRN GREAT LAKES...   ...SYNOPSIS...   A DEEP-LAYER CYCLONE WILL REMAIN OVER THE UPPER MIDWEST THROUGH   SATURDAY MORNING WHILE A BELT OF STRONG CYCLONIC FLOW WILL ARC   THROUGH THE BASE OF THE MID-UPPER TROUGH OVER THE CNTRL PLAINS NEWD   INTO THE GREAT LAKES.  IN THE LOW LEVELS...AN OCCLUDED LOW/FRONT   WILL DRAPE ITSELF OVER THE UPPER MS RIVER VALLEY WITH A COLD FRONT   EXTENDING SWWD INTO THE CNTRL PLAINS WHERE A SECONDARY LEE CYCLONE   OVER THE TX PANHANDLE WILL REMAIN QUASI-STATIONARY DURING THE DAY.    A DRYLINE LINE WILL EXTEND SWD FROM WRN OK INTO TX.     ...OK/KS AND OZARKS...   HIGH QUALITY BOUNDARY LAYER MOISTURE --CHARACTERIZED BY 16 G/KG   LOWEST 100 MB MEAN MIXING RATIO-- SAMPLED OVER THE TX COASTAL PLAIN   ON WEDNESDAY EVENING WILL CONTINUE TO BE DRAWN NWD INTO MUCH OF   OK...BENEATH A REINVIGORATED EML FORECAST TO OVERSPREAD OK/SRN KS   DURING THE DAYTIME HOURS FRIDAY.  DESPITE PROBABLE THURSDAY   NIGHT/FRIDAY MORNING STORMS OVER A PORTION OF THIS REGION...A   RELOADING OF STEEP MID LEVEL LAPSE RATES /IN EXCESS OF 8 DEG C PER   KM H7-H5/ OVER THIS REGION FROM THE W IS LIKELY.  ALTHOUGH THE   DETAILS TO PRIOR STORM ACTIVITY ARE UNCERTAIN BOTH IN TERMS OF THE   EXTENSIVENESS OF CONVECTIVE OVERTURNING AND PLACEMENT OF OUTFLOW   BOUNDARIES...STRONG SURFACE HEATING SHOULD OCCUR IN ITS WAKE OVER   AREAS TO THE S AND SW.     A WEAKLY CAPPED AND VERY TO EXTREMELY UNSTABLE BOUNDARY LAYER IS   FORECAST BY MID-LATE AFTERNOON OVER OK WITH MLCAPE RANGING FROM   3000-4500 J/KG...WITH DESTABILIZATION NOT QUITE AS STRONG FARTHER NE   OVER WRN MO/SERN KS WHERE SOME AIRMASS RECOVERY IS FORECAST TO   OCCUR.  THE ORIENTATION OF THE N-S DRYLINE OVER OK/SRN KS NORMAL TO   STRONG MID-HIGH LEVEL FLOW /NEUTRAL MID LEVEL HEIGHT FIELD/ WILL   SUPPORT EXPLOSIVE DISCRETE SUPERCELL DEVELOPMENT GIVEN THE MAGNITUDE   OF EXPECTED DEEP SHEAR/BUOYANCY.  A LARGE TO PERHAPS EXTREMELY LARGE   HAIL THREAT MAY DEVELOP WITH ANY INTENSE SUPERCELLS.  MODELS DIFFER   REGARDING THE LOW LEVEL MASS RESPONSE OVER OK/KS DURING THE   AFTERNOON/EVENING...WHICH WILL HAVE AN INFLUENCE ON LOW LEVEL SHEAR   AND TORNADO POTENTIAL/INTENSITY.  SOME FORECAST SOUNDINGS SHOW A   RATHER IMPRESSIVE INCREASE IN LOW LEVEL HODOGRAPH SIZE DURING THE   AFTERNOON-EARLY EVENING PERIOD...WHILE OTHER FORECAST SOUNDINGS ARE   MUTED IN THIS LOW LEVEL SHEAR DEPICTION.  REGARDLESS...A LARGE   HAIL/DMGG WIND/TORNADO THREAT WILL EXIST WITH SUPERCELLS THAT   DEVELOP OVER THIS REGION.   ATTM...WILL REFRAIN FROM A HIGHER CATEGORICAL RISK BUT ACKNOWLEDGE   AN UPGRADE MAY BE REQUIRED IN LATER OUTLOOKS...ESPECIALLY FOR A   PORTION OF OK.

[Thundersnow12]

Subjectively, I would say the NSSL WRF has outperformed the SPC 4 km NMM over the past couple weeks, at least the days I've looked at both. So, if one of them is going to show grinders through the metro, I suppose it's the less concerning of the two.

 

Eh I don't know about other days but the SPC 4km WRF nailed 5/18 and 5/19 and on the 19th is was almost perfect. I didn't look at it on the 20th as we were driving back home.

[andyhb]

Eh I don't know about other days but the SPC 4km WRF nailed 5/18 and 5/19 and on the 19th is was almost perfect. I didn't look at it on the 20th as we were driving back home.

 

They both performed fantastically on the 19th, the NSSL WRF basically nailed the locations of the storms and the SPC had the right general idea as well.

[tornadotony]

Subjectively, I would say the NSSL WRF has outperformed the SPC 4 km NMM over the past couple weeks, at least the days I've looked at both. So, if one of them is going to show grinders through the metro, I suppose it's the less concerning of the two.

IDK about that.  Over the past several (many?) years, the EMC WRF has been, subjectively, the dominant of the two IMO.  The NSSL-WRF has a history of taking a long lunch on some events.

[andyhb]

It should also be noted that even if the SPC WRF does not verify for tomorrow...we still have to get through Friday, which, if we get the LL wind response shown on the GFS, could also have some serious potential for OK as the D2 suggests.

[brettjrob]

IDK about that.  Over the past several (many?) years, the EMC WRF has been, subjectively, the dominant of the two IMO.  The NSSL-WRF has a history of taking a long lunch on some events.

 

It's probably best to defer to statistics on this one (if any are available), and your impression may well bear a closer resemblance to them than mine. My feeling over the years has been that the SPC/EMC variant was rather amazing back circa 2007-08, but seems a lot more hit-or-miss in recent years. Regardless, I have no data to back that up, so I'll defer to the three of you who feel otherwise. I'm fairly sure the NSSL-WRF was absolutely fantastic for 5/19 the night before, though.

[andyhb]

It's probably best to defer to statistics on this one (if any are available), and your impression may well bear a closer resemblance to them than mine. My feeling over the years has been that the SPC/EMC variant was rather amazing back circa 2007-08, but seems a lot more hit-or-miss in recent years. Regardless, I have no data to back that up, so I'll defer to the three of you who feel otherwise. I'm fairly sure the NSSL-WRF was absolutely fantastic for 5/19 the night before, though.

 

It was lolworthy how close it was, it had two powerful supercells, one tracking around Edmond and into Lincoln County, and another intensifying around Norman and cranking into Pottawattamie County near Shawnee.

 

I'll see if I can find the graphic.

 

Edit: Graphic has expired, but here's the post I made regarding it: http://www.americanwx.com/bb/index.php/topic/40284-may-15-20-severe-weather-obsdiscussion-part-2/#entry2293672

 

Obviously getting specific here, but those are some high impact areas those things are tracking through/near. The north one comes from Northern OK county (Edmond) and the southern one moves perilously close to Norman and is heading towards Shawnee in that image.

[dljuly3]

It was lolworthy how close it was, it had two powerful supercells, one tracking around Edmond and into Lincoln County, and another intensifying around Norman and cranking into Pottawattamie County near Shawnee.

 

I'll see if I can find the graphic.

 

Edit: Graphic has expired, but here's the post I made regarding it: http://www.americanwx.com/bb/index.php/topic/40284-may-15-20-severe-weather-obsdiscussion-part-2/#entry2293672

 

I think this is what you are looking for:

 

 

Crazy hooked supercell structures from that run. Just incredible how well it performed.

[OUGrad05]

I can't help but think the atmosphere here in the Tulsa area and out to our west, Osage, Pawnee, Creek counties that the atmosphere is just thoroughly wrung out.  We had storm after storm after storm last night and now we're sitting under a thick blanket of clouds.  The clouds are rushing to the north at a pretty good clip and are quite low, perhaps around 1,000 feet. 

 

It will be interesting to see if the atmosphere can reload after last night and this morning's almost endless convection.

[HM]

I can't help but think the atmosphere here in the Tulsa area and out to our west, Osage, Pawnee, Creek counties that the atmosphere is just thoroughly wrung out.  We had storm after storm after storm last night and now we're sitting under a thick blanket of clouds.  The clouds are rushing to the north at a pretty good clip and are quite low, perhaps around 1,000 feet. 

 

It will be interesting to see if the atmosphere can reload after last night and this morning's almost endless convection.

If only it worked this way, forecasting would be so much easier.

 

You are describing a human-like trait to something that isn't human. If conditions become favorable again, it won't matter. In fact, many past great outbreaks/tornado days start out this way.

[lowleveljet]

If only it worked this way, forecasting would be so much easier.

 

You are describing a human-like trait to something that isn't human. If conditions become favorable again, it won't matter. In fact, many past great outbreaks/tornado days start out this way.

SPC just went moderate on latest day1 for the Tulsa area.

[HM]

 

SPC just went moderate on latest day1 for the Tulsa area.

Yes they did. The pseudo-warm front feature in KS-N OK (like last weekend) is a good mention from the SPC. The 6z NAM/GFS really back the winds near this thing later on too; while deeper into the warm sector, the winds remain a little more southerly.

SETUP LIKELY WILL BE MORE THAN SUFFICIENT FOR A

COUPLE STRONG TORNADOES. THIS THREAT MAY MAXIMIZE NEAR SHALLOW WARM

FRONTAL FEATURE OVER CNTRL/ERN OK...WHERE SFC FLOW IS LIKELY TO

REMAIN SLIGHTLY BACKED. IN ADDITION...IF STORMS LINGER INTO THE

EVE...THEY WILL FIND THEMSELVES IN AN ENVIRONMENT OF INCREASING

LOW-LVL SHEAR AS THE LLJ NOT ONLY STRENGTHENS NOCTURNALLY...BUT ALSO

IN RESPONSE TO THE APPROACH OF UPSTREAM JET STREAK NOW OVER THE GRT

BASIN.

[HM]

This morning's OUN sounding is pretty ridiculous:

 

http://www.spc.noaa.gov/exper/soundings/13053012_OBS/OUN.gif

Edit: Even knowing that low-level winds will reduce with typical diurnal cycle / advancing eastward and there is some evidence for slight backing in the mid levels, the sounding is still nasty.

The forecast hodographs are not quite Monday-like at this point. But we are closer today than yesterday, that's for sure.

[baroclinic_instability]

There is something seriously different when you read a disco from an incredible met like Corfidi. You really feel like an expert is speaking. Not that others at SPC are not experts, but Corfidi is special among a group of "special" forecasters.

 

That said, today has a lot of potential.

[soonertrey]

The MCS around the I-35 corridor in S KS/N OK seems like it's trying to trend south just a touch.  Hopefully it doesn't make it much further south.

[Ian]

Sounds like the DOWs got violent winds on the Bennington tor the other day. See no rating yet tho the NE KS was a strong 3. Bennington might have been a 5 if they use the winds from DOW. Prob a 4 for at least. Tho not sure it hit much so who knows what they'll do I guess.

[OUGrad05]

I can't help but think the atmosphere here in the Tulsa area and out to our west, Osage, Pawnee, Creek counties that the atmosphere is just thoroughly wrung out.  We had storm after storm after storm last night and now we're sitting under a thick blanket of clouds.  The clouds are rushing to the north at a pretty good clip and are quite low, perhaps around 1,000 feet. 

 

It will be interesting to see if the atmosphere can reload after last night and this morning's almost endless convection.

If only it worked this way, forecasting would be so much easier.

 

You are describing a human-like trait to something that isn't human. If conditions become favorable again, it won't matter. In fact, many past great outbreaks/tornado days start out this way.

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.

Sent from my DROID RAZR using Tapatalk 2

[Ian]

Some pics from recent days

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/05/30/the-stormy-plains-awesome-supercell-structure-and-a-big-tornado-photos/

[baroclinic_instability]

Some pics from recent days

http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/05/30/the-stormy-plains-awesome-supercell-structure-and-a-big-tornado-photos/

Not sure if already posted, but NIU prof Walker Ashley got some sick pics/vids (almost the same as Mark's) of the Ansley LP. http://thetae.blogspot.com/2013/05/5262013-cod-trip-3-day-3.html

 

Edit: One of the most incredible supercell timelapses I have ever seen.

[Bozart]

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.