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June 17th-22nd severe threat


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More or less. No classes over the summer, and I pretty much do my grad research on my own schedule, save for occasional meetings. If there were a really active stretch I might have to get picky so as not to neglect work stuff for too long and let it pile up, but that hasn't really been a problem this year :rolleyes:.

Still unsure on pursuing tomorrow, moreso because of the financial aspect than anything else, but figured I'd mention it anyway.

cool, makes sense. you've done fairly well this yr still it seems. why dont you have a red tag? ;)

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Obviously a ton of uncertainty today, but if something can fire in Central/Eastern Illinois/Western Indiana, the local atmosphere with the boundaries leftover from this mornings mcs might be enough to make things mildly interesting. Also nice job to Alek for recognizing early that the mcs train would likely hold the warm front farther South.

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16Z Severe Weather Threat via SmartModel, right now showing areas in and near Hopkinsville, KY - Branson, MO - Grove, OK - Farmington, MO - Joplin, MO to Sparta, IL. Current values are SFC CAPE's 2500-3600 j/kg, LI's -9, 0-3KM SRH 230 m/s, Seeing convective gust potential up to 70 knots, hail up to 1" in diameter. Details uploaded

usa.jpg

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Obviously a ton of uncertainty today, but if something can fire in Central/Eastern Illinois/Western Indiana, the local atmosphere with the boundaries leftover from this mornings mcs might be enough to make things mildly interesting. Also nice job to Alek for recognizing early that the mcs train would likely hold the warm front farther South.

There is a warm front that extends from the IA/MO border eastward into North-Central Illinois (Between PIA & I-80), and then into Northern Indiana.

There is a second outflow enhanced boundary farther south in SW. Missouri, Northern Arkansas, and Tennessee.

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Springfield, MO is planning a 19z sounding, calling for sig severe weather. All modes possible. 4000-6000 MLCAPE :-\

Yeah I'm thinking unfortunately that Andy (the AFD writer at SGF) is spot-on. In fact, I kinda fear what might happen along any boundary down there, as low-level shear, though not great, should be sufficient for tornadoes and instability is going to be massive.

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Yeah I'm thinking unfortunately that Andy (the AFD writer at SGF) is spot-on. In fact, I kinda fear what might happen along any boundary down there, as low-level shear, though not great, should be sufficient for tornadoes and instability is going to be massive.

yeah, always hate being around any boundary.

The CAPE is my other worry as there was around 4000-5000 around during the EF-5 along with I believe around 43-46kts shear.

Hoping that shear will be a little weaker and LCL's will be higher.

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Latest 12z GFS has the 500mb jet steak impacting more of Oklahoma on Monday, right at peak heating. EML from hell still, but dews in the 70's and CAPE exceeding 3,000 j/kg should be enough to initiate isolated supercells. Tornado threat a little in question, but significant severe seems probable to me over the northern half of OK, including OKC.

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Latest 12z GFS has the 500mb jet steak impacting more of Oklahoma on Monday, right at peak heating. EML from hell still, but dews in the 70's and CAPE exceeding 3,000 j/kg should be enough to initiate isolated supercells. Tornado threat a little in question, but significant severe seems probable to me over the northern half of OK, including OKC.

It doesn't really matter much what the dews/CAPEs are, it's just not likely to happen with 700mb temps running 13-16°C. Could some convection form near dusk as the LLJ ramps up? Sure, but I doubt it's overall major significance as it would most likely be rooted above the boundary layer. I could see a hail threat, but I doubt it's going to be overwhelmingly significant.

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It doesn't really matter much what the dews/CAPEs are, it's just not likely to happen with 700mb temps running 13-16°C. Could some convection form near dusk as the LLJ ramps up? Sure, but I doubt it's overall major significance as it would most likely be rooted above the boundary layer. I could see a hail threat, but I doubt it's going to be overwhelmingly significant.

The trend has been for the mid level low to track further south. Each model run continues to cool off 700mb temps. We're not talking about 13-16C anymore. More like 12-14C

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The trend has been for the mid level low to track further south. Each model run continues to cool off 700mb temps. We're not talking about 13-16C anymore. More like 12-14C

Also, the GFS, which is normally stingy breaking out convection in scenarios such as this, now shows convection breaking out in the afternoon. Am I saying this is a May 24th type of outbreak in Oklahoma? Not even close. But it is significant for Oklahoma in late June.

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trend continues to be toward a sharper trough. Looks to me like a solid threat for discrete supercells and certainly a few tornadoes north of OKC Monday evening

Nope, unless by N of OKC you mean N of Wichita. With 13-16°C H7 temps, the kind of convective temps you would need to break the cap (probably upper 90s-100s) would dictate high LCLs and a distinct unlikelihood of tornadoes. Look at the GFS model soundings for 00z Tuesday (Monday evening). By then, yes, the cap is nearly eroded (emphasis on nearly) along the dryline. The LCLs are also above 1500m. Will not do it. To the east, where the LCLs would favor tornadoes, the cap is still thermonuclear. The main push of differential CVA/lift does not arrive until right around 00z. By the time storms form after 00z, three things will likely be happening. First is that the boundary layer will begin to decouple, thus causing activity that forms to be elevated and of little/no tornado threat. Second is that shear vectors will likely back a bit, increasing linear forcing and decreasing the potential for storms to remain discrete. Third thing is that, according to the GFS and with NAM support (though I abhor using the NAM right now), the cold front should be overtaking the dryline by that time, also increasing forcing for ascent and decreasing discrete supercell potential. Now that will likely break the cap, but by then storms will be elevated and it can be very difficult to get sig severe from elevated convection, though not impossible (hail being most likely).

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The trend has been for the mid level low to track further south. Each model run continues to cool off 700mb temps. We're not talking about 13-16C anymore. More like 12-14C

Also, the GFS, which is normally stingy breaking out convection in scenarios such as this, now shows convection breaking out in the afternoon. Am I saying this is a May 24th type of outbreak in Oklahoma? Not even close. But it is significant for Oklahoma in late June.

What about LCL heights, though? Surface temps are progged at 95-105 F for central and northern OK. This means two things, IMO: (1) surface-based convection is still a possibility, despite the outrageous mid-level warmth; and (2) said surface-based convection, should it occur, will be based approximately at the height of Mars and pose more of a downburst threat (ala 6/14) than anything else.

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What about LCL heights, though? Surface temps are progged at 95-105 F for central and northern OK. This means two things, IMO: (1) surface-based convection is still a possibility, despite the outrageous mid-level warmth; and (2) said surface-based convection, should it occur, will be based approximately at the height of Mars and pose more of a downburst threat (ala 6/14) than anything else.

I agree about LCL heights. By significant severe, I really mean a threat of huge hail and widespread damaging winds similar to 6/14, but possibly affecting more areas. There's going to be a lot more forcing Monday than there was last week.

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SPC uses the phrase "Signifigant Wind Damage" in the slight risk area. Sombody with no life please send them a complaint.

ERN KS/MO...

THE SURFACE BOUNDARIES THAT EXTEND WWD ALONG MO/AR BORDER WILL BE

LIKELY FOCUS OF SEVERE THUNDERSTORM DEVELOPMENT BY LATE THIS

AFTERNOON AS CAP WEAKENS AND MLCAPES CLIMB AS HIGH AS 4000 J/KG.

WHILE THE CINH WILL BE AN ISSUE UNTIL LATE THIS AFTERNOON...WHEN

STORMS ARE ABLE TO INITIATE ALONG BOUNDARY THEY SHOULD QUICKLY

BECOME SEVERE GIVEN THE POTENT THERMODYNAMICS.

WITH THE LOW LEVEL JET INCREASING THIS EVENING TO 40KT SEVERE

THUNDERSTORMS SHOULD DEVELOP UPSCALE LEADING TO ONE OR MORE MCS/S

AGAIN TONIGHT FROM ERN KS ACROSS MO. IN ADDITION TO VERY LARGE HAIL

IN THE INITIAL STAGES OF INITIATION...DAMAGING WINDS WILL BE ON THE

INCREASE...PRIMARILY AFTER 00Z WHEN THE SHEAR IMPROVES AND COLD POOL

DEVELOPMENT OCCURS. POSSIBLY SIGNIFICANT WIND DAMAGE COULD OCCUR

THIS EVENING PARTS OF ERN KS AND MO.

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Looking pretty primed southeast of Wichita right now. Two boundaries laying in the area too: one easily visible on the ICT 88D and the other with the 70 dewpoints just over the border in Oklahoma. SPC mesoanalysis page and short fused tools would suggest initiation takes place just south of Wichita.

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Springfield MO meso discussion mentions the 19z sounding is in progress. 700 MB temps of 14-16 degrees with -50 CIN. So storms will probably fire west of here and head this way. They mention good cold pool balance and possible spin-ups along the outflow boundaries as well as hail larger than golf ball size possible.

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Nope, unless by N of OKC you mean N of Wichita. With 13-16°C H7 temps, the kind of convective temps you would need to break the cap (probably upper 90s-100s) would dictate high LCLs and a distinct unlikelihood of tornadoes. Look at the GFS model soundings for 00z Tuesday (Monday evening). By then, yes, the cap is nearly eroded (emphasis on nearly) along the dryline. The LCLs are also above 1500m. Will not do it. To the east, where the LCLs would favor tornadoes, the cap is still thermonuclear. The main push of differential CVA/lift does not arrive until right around 00z. By the time storms form after 00z, three things will likely be happening. First is that the boundary layer will begin to decouple, thus causing activity that forms to be elevated and of little/no tornado threat. Second is that shear vectors will likely back a bit, increasing linear forcing and decreasing the potential for storms to remain discrete. Third thing is that, according to the GFS and with NAM support (though I abhor using the NAM right now), the cold front should be overtaking the dryline by that time, also increasing forcing for ascent and decreasing discrete supercell potential. Now that will likely break the cap, but by then storms will be elevated and it can be very difficult to get sig severe from elevated convection, though not impossible (hail being most likely).

A bit off topic, but it is worth mentioning the parallel run of the new NAM set to be luanched mid July has performed superior to the operational NAM beyond 48 hours the entire last week that I have analyzed it. A good example is the handling of the current PV which is now bombing sub 990 in SK which was handled in superior fashion by the parallel and pretty much in agreement with global guidance on the larger scale synoptic flow. Our friend the operational NAM was a joke and barely had a surface low beyond 72 hours in its older progs.

http://www.nco.ncep....wpara/analysis/

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MESOSCALE DISCUSSION 1279

NWS STORM PREDICTION CENTER NORMAN OK

0334 PM CDT SAT JUN 18 2011

AREAS AFFECTED...EXTREME NERN OK...SERN KS AND SWRN MO

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 182034Z - 182230Z

NERN OK...SERN KS AND SWRN MO ARE BEING MONITORED FOR THUNDERSTORM

INITIATION AND POSSIBLE WW. TIMING OF INITIATION IS SOMEWHAT

UNCERTAIN. HOWEVER...ONCE STORMS DEVELOP THEY WILL LIKELY RAPIDLY

BECOME SEVERE WITH SUPERCELLS...LARGE HAIL AND A COUPLE TORNADOES

THE INITIAL THREAT. ACTIVITY SHOULD EVENTUALLY TRANSITION TO AN MCS

WITH AN INCREASING THREAT OF DAMAGING WIND DURING THE EVENING.

LATE THIS AFTERNOON A QUASISTATIONARY FRONT EXTENDS FROM A SURFACE

LOW IN NWRN OK NEWD THROUGH SERN KS AND SWRN MO WHERE IT INTERSECTS

A REMNANT OUTFLOW BOUNDARY THAT EXTENDS FARTHER SEWD INTO NERN AR.

THE WARM SECTOR HAS BECOME VERY UNSTABLE WITH A VERY WARM AND MOIST

BOUNDARY LAYER /70+ DEWPOINTS AND 90+ TEMPERATURES/ BENEATH STEEP

MID LEVEL LAPSE RATES SUPPORTING 4000+ MLCAPE. HOWEVER...THE BASE OF

THE EML THAT HAS SPREAD OVER THE REGION IS VERY WARM WITH 700 MB

TEMPERATURES AROUND 14C RESULTING IN A STRONG CAP WHICH WAS SAMPLED

ON THE SPRINGFIELD MO AND LAMONT OK SPECIAL RAOBS.

VISIBLE IMAGERY SHOWS CUMULUS INCREASING WITHIN THE ZONE OF MASS

CONVERGENCE NEAR THE STATIONARY FRONT AND OUTFLOW BOUNDARY...AND IT

IS POSSIBLE STORMS COULD DEVELOP IN THIS REGION BY 22Z.

HOWEVER...INITIATION POTENTIAL SHOULD INCREASE CLOSER TO 00Z AS THE

LLJ STRENGTHENS AND AUGMENTS LIFT ALONG AND NORTH OF THESE

BOUNDARIES. VERTICAL SHEAR AROUND 40 KT WILL SUPPORT SUPERCELLS

WITH VERY LARGE HAIL LIKELY. A SMALL WINDOW MAY EXIST FOR ISOLATED

TORNADOES AS THE LLJ STRENGTHENS AND BEFORE THE BOUNDARY LAYER

DECOUPLES. OTHERWISE THE PRIMARY THREAT SHOULD TRANSITION TO

DAMAGING WIND AS THE EVENING PROGRESSES.

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