4/10/08 FCST: OK/TX/MO/AR/KS/TN/IL/KY

[Ryan Pfannkuch]

Boy, the 12z NAM sure seems quick lifting the sfc low well into southwest IA by 0z. The 12z GFS is at least 100 miles farther SW, while the 9z SREF looks like a good compromise. One of the more intriguing things I've seen this morning is the 13km DEV RUC, which hangs this thing WAY back west of the operational NAM/GFS, with the sfc low at mid-afternoon along central portions of the NE/KS border. Below is the CAPE fcst for 21z, and if this RUC is onto anything at all, parts of southeast NE and southwest IA would likely see an increase in SVR probabilities as well. This seems like quite an outlier, but bears watching. Gonna be really interesting to watch the trends of these surface features over the next 24-30 hours, that's for sure.

http://ruc.noaa.gov/disp2.cgi?/w3/rapb/plots_13km_dev/.//+cape+nc+30

 

[Adam Lucio]

I also like the quincy area and might make this my general target area. Will adjust based on live conditions. Looking at the google earth satalite I see lots of farmland.

The eastern trend that has been discussed is what I have been hoping for. There isnt much I can add that hasnt been said already. Storms speeds are going to be ridiculous.

It burns me up to have such amazing dynamics in place that can potentialy go to waste to the dreaded junkvection from the night before. I think with the quicker movement of the low this could skirt it out of the area early enough to allow the dry punch to give us some clearing. Im going to keep my target fairly general as of now and say anywhere from Quincy northward to Burlinton, I am also going to be prepared for a more southern target as well based on live conditions. Surface heating and better instabiity is the only thing that would draw me to a more southern target.

It looks like a nice tounge of higher dews will get rocketed into Central IL by 0Z Friday along with the best surface heating from eastern MO into central IL. GFS is showing the low at 988mb over NEern KS by this time. ECWMF is a little slower with the placement but also brings it down to 988mb. I like the GFS solution a little better.

My hopes is that the strong dynamics along the warm front can overcome the lack of instability, I believe 500 j/kg CAPE is all we will need.

Good luck to everyone and be safe out there.

 

[Jesse Risley]

I also like the quincy area and might make this my general target area. Will adjust based on live conditions. Looking at the google earth satalite I see lots of farmland.

The eastern trend that has been discussed is what I have been hoping for. There isnt much I can add that hasnt been said already. Storms speeds are going to be ridiculous.

It burns me up to have such amazing dynamics in place that can potentialy go to waste to the dreaded junkvection from the night before.

I sure hope the cloud cover doesn't blow this one, although we've had "outbreaks" in this region in the past which were fueled by well less than 1000 J/KG CAPE.

For those targeting this area, the backroad networks are very favorable for chasing too. Many of the backroads are blacktop and the area is relatively flat. One caveat: Due to the anticipated storm speeds, remember that there are limited crossings on the Mississippi in this neck of the woods.

 

[Marcus Opitz]

I am liking the Mt. Vernon, IL area as it has a nice N/S E/W interstate there. I am biased to the south as I worry that instability may be lacking to the north. I have a feeling the northern portion of the risk area will be plagued by convective debris from today and tonight as upper winds seem to veer more and more from the SW to NE or NNE. I would'nt be surprised if SE MO near sikeston gets some of the initial action tommarow...Some of the good stuff may fire in the St. Francis Mtns area too. (bad chase terrain though)

***edit

30-36 hour GFS and ETA show some diverging of the winds at 500mb in S. IL. However it looks like the main jet core will traverse the Quincy, IL area.

 

[Brandon Sullivan]

Wow.. After looking at the 12z Data, I am even more stoked for the prospects of a nice Chase In Northeast Missourri...
The 12z NAM shows 1000+ CAPE at 00z Friday. Which should be more than sufficient with the kinematics in place..
12z WRF Appears to have sped it up a little bit. The 9z SREF showing some nice STP's and Supercell composites...
I am looking somewhere in NE Missouri, maybe around Hanibal, where I have access to get back across the river easily..

I like the 12z Sounding from KUIN(Quincy)
Lifted Index: -4.85 C Risk: Severe thunderstorms probable
Lifted Index @300 mb: -1.01 C
Lifted Index @700 mb: -4.85 C
Showalter Index: -2.57 C Risk: Severe thunderstorms possible
Sweat Index: 427.06 Risk: Severe Thunderstorms possible
Energy Index: -2.12 Risk: Severe Thunderstorms probable
CAPE (B+): 1182.29 J/kg
Conv Inhibition (B-): 3.76 J/kg
Cap Strength: 0.28 C
Lift Cond Lev (LCL): 882.92 mb
Lev Free Conv (LFC): 867.92 mb
Equ Level (EL): 287.92 mb = 9465.32 m = 31053.83 ft
Max Parcel Lev (MPL): 167.92 mb = 12980.61 m = 42586.77 ft
Storm direction: 237.3 at 52.5 knts
Shear (0-3000m) pos: 7.8 neg: 0.0 tot: 7.8 10-3/s
Storm rel Dir Shear (0-3000m): 73.9 deg
Storm rel helicity (0-3000m) pos: 493.7 neg: 0.0 tot: 493.7 m^2/s^2
ave: 164.6 10^-3 m/s^2 rel: 0.84
Storm rel vorticity (0-3000m) horiz: 9.8 stream: 8.3 10^-3/s
Energy-Hel index: 3.21
Bulk Rich Number: 5.45
Bulk Shear: 216.75 m/s


WHEW! Look at that storm motion..

 

[Scott Weberpal]

00z NAM hangs the sfc low back a bit, and likely puts the game back in Missouri. I'm not all that afraid of chasing Northern Missouri north of I-70, so I may head that direction. I'm still concerned about something big happening along the nose of the H5 jet somewhere between St. Louis and Quincy before dark. It seems typical in these big kinematic events to have a massive beast initiate along the nose of the jet and go bonkers.

Insolation still and issue, but not as concerned with that as I am with storm motion. Please, buy a rocket pack if you plan to chase tomorrow.

 

[Brandon Sullivan]

Looking at the 00z Data, my plan is somewhat unchanged.

The NAM still shows some nice dry air working into the low levels in the afternoon over Northeast Missouri, which I am banking on to erode low level clouds and provide some nice insolation...

LSX updated AFD says outbreak appears increasingly likely... I want to head to KUIN and see what is going on when I get there.. Then maybe go West or South.... 2000+ CAPE apearing in Western IL at 00z...

Would like to wish everyone best of luck though! Hope she goes high risk!!

 

[Donald Giuliano]

One key difference, I notice though, is that there was a significant inversion w/ very dry air @700mb across much of the warm sector on 4/3/74.

Good point, IIRC the 4/3/74 system advected the dryline so far east it made it well into Tennessee. Although drylines frequently make it into AR, having one plow deep into TN is a highly unusual.

 

[Jim Zandonai]

Hmm appears the SPC backed off a little on its Thursday(now day 1 outlook) Looks like they are sticking with MDT risk and have removed the strong wording of long tracked Tornadoes etc. interesting how the MDT risk now has been angled more NE then North south too.. While this appears to be a significant outbreak still it appears not to be a record or next 'super outbreak' some were hinting at..which isnt a bad thing..

 

[beaudodson]

Hmm appears the SPC backed off a little on its Thursday(now day 1 outlook) Looks like they are sticking with MDT risk and have removed the strong wording of long tracked Tornadoes etc. interesting how the MDT risk now has been angled more NE then North south too.. While this appears to be a significant outbreak still it appears not to be a record or next 'super outbreak' some were hinting at..which isnt a bad thing..

SPC backed WAY off the strong wording of the last few days. The development of the squall line tonight that should push all the way into Arkansas seems to be a factor in this. The storm appears to be occluding earlier than forecast as well. The new day 1 is only a 10% on the tornado threat. Certainly a far cry from what earlier forecasts were showing. We will see if that holds later this morning.

I have seen national news stories that said we were looking at an historic outbreak and so on. Course that came from one main source.

Hopefully we have dodged a major outbreak bullet in this region. Tomorrow morning will be nowcasting time. The WRF tonight is interesting - it plows a strong squall line from Missouri to Arkansas and into Texas tomorrow morning. Then it shows new cells forming in eastern Kansas and western Missouri around noon.

 

[SteveCarter]

Definately backing off on any 'historic' weather events...outbreaks now. Of course, when you think about it, the only direction the forecast COULD go was to back off...they had this at such a high probability it was getting to sound skeptical anyway. Having said THAT......I've already driven 450 miles, took two days off work, and signed away the rights to any future Grandkids for gas....so I'm here for the run. My target area is Russellville, Arkansas. Seriously thought about the Boot of MO, but.......who knows right now? I'm in Corinth, MS, getting ready for a few hours of sleep. I think this will be a good day, but not like it was built up to be...which could be a good thing anyway. note***Another 'hot' spot may be south central MO, but the terrain there is horrific. If any chasers out there REALLY want to get some great action...just follow 90 minutes behind me, because things always happen AFTER I leave the area.

 

[Rob Lightbown]

Taking a look at the severe/tornado threat later today. Based on the SREF/NAM model parameters, I see two areas of concern:
Area one is southeast Missouri eastward into the Memphis area, which the STP parameter is fairly high and CAPE values will more than support severe storms/tornadoes. Time frame for area one is between 4 pm eastern/3 pm central and midnight eastern/11 pm central.

Area two actually concerns me a little more. Based on the 00 and 06Z NAM model, it appears that there will be a secondary max of CAPE of around 1500 will move into the Springfield/Macomb area of Illinois. 0-1 km Helicity values in this area will be 200-300 and 0-3 km Helicity values of up to 350. In addition, STP values max out at 7+ in the Springfield/Macomb area. So I'm thinking that supercells may actually form/track across northeastern Missouri (Kirksville-Columbia area) by 4-5 pm eastern/3-4 pm central tracking into the Springfield/Macomb area between 8 and 10 pm eastern/7 and 9 pm central time.

So, those are my thoughts.

 

[beaudodson]

Early morning here as severe thunderstorms are moving into southeast Missouri from northeast Arkansas.

Would not be surprised to see an upgrade to high risk for portions of AR/MO/MS/TN. Satellite this morning shows a lot of clearing across portions of the above mentioned area (other than MO). The 64 dewpoint line is draped across the southern half of the State of Arkansas. Sixty dewpoint line is now approaching southeast Missouri and western Kentucky. Memphis is already 70 degrees. Temperatures have risen from the fifties last night at 2 a.m. into the sixties already this morning (before sunrise) in western Kentucky.

Latest guidance shows the low may deepen even further than forecast. This as a powerful squall line is moving across portions of Oklahoma and Texas.

CAPE values at 5 a.m. are already over 500 across southern Arkansas. It won't take much sunshine/breaks in the clouds to cause those values to go up through the day.

SPC analysis page shows that the supercell composite is ranging from 4 to 30+ in Arkansas. Any storms that can form ahead of the squall line will rapidly go severe today with the potential for tornadoes. Wind fields are strong. Widespread wind damage is being reported with the squall line. That should continue through the morning and afternoon.

Will be curious to see if SPC will upgrade to a high risk later this morning. I wonder about the greater potential across northern Missouri into Illinois late this afternoon and evening. WRF certainly shows the potential for discrete storms in that region.

Jackson, MS AFD
WE WILL BE SENDING UP SPECIAL
RAOBS AT 18Z PER SPC REQUEST AND POSSIBLY AGAIN 21Z.

 

[Michael O'Keeffe]

I'm hoping for some action here close to the surface low in E KS/W and N MO along the warm front and dryline. The water vapor imagery is showing a nice dry punch immediatly after the rain moves through which should be through this area by 10am at the latest. So that could give us at least three or four hours of destabilization before what looks to be a line of low-topped supercells with tornadoes over E KS, NC/NW/C MO eventually reaching NE MO/WC IL/extreme SE IA by evening. I think all we need is some sort of destabilization and we could see tornadic supercells. Basically looks to me like a cold core setup given close proximity to the surface low. Good luck to all chasing!!

 

[Mark Sefried]

I was seriously thinking about chasing East Central MO last night per the NAM. However based on the ruc I do not like the fact that it is showing around 500 cape and less this afternoon as of 6:30 this morning. The ruc is showing that the temps do not increase fast this afternnon in the dry punch area which is telling me that there will not be much clearing (maybe some but posssibly not enough). I didn't get much time this morning to look at things in great detail, however I did not like what I saw.