4/24/10 FCST. IL. KY. TN. MO. LA. MS. AR

[Kevin Askew]

Ill leave the forecasts to the experts here but if the NAM pans out, we are likely to see a good day both days. Saturday looks like an increasingly good shot of severe and or possibly tornadoes. Initally targeting the KMEM area day or evening. Good luck to the chasers/spotters out there and this is most likely the first big potential severe weather setup this year so far FRI-Sat event.

 

[Chris Heater]

This is the only day I can chase, and my initial target is Jonesboro, AR. I'll probably go a lot further than that (more closer to Little Rock, AR) but in eastern AR I like the large curved hodographs, low LCL numbers and moderate instability. If it pans out there may wind up being a tornado outbreak down there. I know Memphis, TN NWS is getting a little worried about it and with me fair amount of model consistency 4 days out I think their right. What does everyone else think?

 

[Kevin Askew]

Yep, last 2 days they seem very concerned.. The morning exerpt ill post here points to a tornado outbreak directly. We are still targeting I-44 Corr. Blytheville through Memphis. Storms depending on cap may hold off until late afternoon which may be much worse for the population.
SEVERE POTENTIAL IS MUCH HIGHER FOR SATURDAY. VERY STRONG
SHEAR...STRONG FORCING...AND A MOIST/UNSTABLE AIRMASS SHOULD ALLOW
FOR WIDESPREAD SEVERE THUNDERSTORM ACTIVITY. TORNADO PARAMETERS
CONTINUE TO INDICATE THE POTENTIAL FOR A TORNADO OUTBREAK DUE TO
THE LOW LCLS...LONG LOOPING HODOGRAPHS...AND SFC INSTABILITY. STEEP
LAPSE RATES SHOULD ALSO SUPPORT VERY LARGE HAIL. ALL MODELS ARE IN
GENERAL AGREEMENT WITH THIS...SO CONFIDENCE IS QUITE HIGH FOR
BEING 4 DAYS OUT.

 

[beaudodson]

The KPAH sounding for Saturday afternoon is impressive with backing winds. There are a ton of questions that remain as to the exact development and track of the low pressure area on Saturday. The 12z NAM takes the low from Arkansas to southern Illinois. This causes the winds to back over west KY - some instability, as well.

Lot of questions remain as to how this evolves. Would not be surprised to see some moderate risk days ahead of us.

 

[Kevin Askew]

The KPAH sounding for Saturday afternoon is impressive with backing winds. There are a ton of questions that remain as to the exact development and track of the low pressure area on Saturday. The 12z NAM takes the low from Arkansas to southern Illinois. This causes the winds to back over west KY - some instability, as well.

Lot of questions remain as to how this evolves. Would not be surprised to see some moderate risk days ahead of us.

Yes Paducah is ripening slowly {dependant on SLP track} for severe wx. We very well could end up in our home area for this yet. Still holding on E AR/W TN for our team but could change if this keeps trending slowly and slightly to north. In any case, it possibly will be a busy day for some WFO's
2-4 Pmish as the looks of it right now for timing. but still a ways out to give any kind of certainty...

 

[Chris Heater]

After seeing the 0Z NAM things don't look as great for our original target of E AR to W TN. By early morning, nearly all the CAPE disappears from that area along with the other parameters such as STP's. Hope this is just a fluke as the past couple of days there was talk it could be a tornado outbreak in that area (large curved hodographs, moderate instability, etc). Will be VERY interesting to see what the models do tomorrow

 

[beaudodson]

After seeing the 0Z NAM things don't look as great for our original target of E AR to W TN. By early morning, nearly all the CAPE disappears from that area along with the other parameters such as STP's. Hope this is just a fluke as the past couple of days there was talk it could be a tornado outbreak in that area (large curved hodographs, moderate instability, etc). Will be VERY interesting to see what the models do tomorrow

Models are showing a large complex of storms coming out of TX and OK/LA. So this could really cut down on instability further north. NAM makes some attempt to destabilize the atmosphere over portions of southern MO, southern IL, and Kentucky. But - with all that cloud mess to the south - moving north/northeast one wonders just how much instability there will be. Also the placement of this small low (assuming the convective feedback issues are not causing problems) is still in question. Seems like the models want to take it from eastern Arkansas into the southern Illinois region - maybe Kentucky.

Tough call on what happens Saturday. Looks like a lot of potential - but potential may not be realized if the Friday night and Saturday morning complex messes everything up.

Hard forecast

 

[Dave Marshall]

The GFS still looks awfully pessimistic, but the NAM has moved back toward decent instability in the KY/IL/AR/TN quad state area at 18z. That instability carries NE into Indiana by 21z. I would *love* to see some of that instability line up with the wicked vorticity maximum that the GFS is bringing north out of MS into the TN/KY/IL area around the same time frame.

 

[Kevin Askew]

This will be a morning of to decide target. Gonna be a tough call. See how much the cloud debris can break up in early late morning. Im allowing 3 hrs drive time so we ok there. Friday aft/eve/ngt/ I think look better here in our area for severe, tough to call, But almost bet if cloud debris on early morning infra red shows them drying, I would not be surprised to see a MOD for here. Anywhere from Memphis and Nashville areas looks rather ominous if the debris moves out of the way. Still holding that target for us ATM

 

[Zack Hargrove]

I'm thinking Northern Alabama might be interesting on Saturday also, and would even maybe suggest it be added to this list. A few fellow students from up here at University of NC Asheville and msyelf are headed towards the Huntsville area on Saturday where we will re-assess and maybe make our way into MS.

 

[beaudodson]

I would not be surprised to see a large moderate or high risk for Saturday across portions of Arkansas, Tennessee, Alabama, Mississippi, and Louisiana. More questions on how Kentucky evolves.

0z data takes a low from eastern Arkansas (upper 990s) and deepens it to 985 or lower over Indiana. Quite impressive in a short amount of time.

Soundings for a large area show winds backing on Saturday afternoon. SREF tornado parameters are quite impressive over MS/TN/AL. I guess the biggest question will be ongoing convection and severe weather Saturday morning.

But - looks like a potential significant tornado outbreak. The afternoon Jackson, MS area forecast discussion is just incredible. Never seen anything worded quite like that. Defin a must read.

 

[Kevin Askew]

Absolutely the Alabama target looks good. Tomorrow through Sat. evening SREF runs look amazing. Adjusted target a bit to cover through Nashville area too. We still look to get into MEM area close to noon, If booms earlier we can adjust on the road to intercept. Good luck to all out there chasing tomorrow and sat.!

 

[Dave Marshall]

The GFS has been perpetually pessimistic, and the NAM continues on it's trend of waxing and waning regarding instability north of the MS/TN line. The 06z run was a 'wax' and the 12z is a 'wane'. I don't think it's handling the ongoing precip very well. Instability really seems to be the big question mark right now.

The model variance is making it tough for me to call a target, or really even decide if it's worth the ~12 hour drive. If I do go, I'd be happy to have a ride-along. If anybody is in the Ohio/southern NY/Western PA area, let me know if you'd like to come along.

 

[Chip Redmond]

All in all, a very spread out region to consider and not exactly a easy forecast. Was looking at the TN/AL/MS intersection but I am very concerned with the lack of instability with a line of storms moving though early afternoon, no afternoon heating will have time to take place. There is ample moisture but the linearity and cluster type of storms will not be conducive of supercells. SPC seems to be really ramping up the MS valley for long track sup's but I just don't see them remaining in front of the cold front as long as expected.

With so much cloud cover from today and tonight's storms across the region in the northern sector (TN,KY) this will also limit instability. I don't forsee the low level jet actually making it this far north and being of any significance.

After much consideration, I am going to sit this one out. Good luck to everyone out there tomorrow! Hopefully I am wrong!

Chip

 

[Kevin Askew]

Very interesting setup continues to be a issue on how and how fast the second SLP develops and deepens by the arrival time in Indy Sat. night. models having tough time with it. Tonight worries me when the LLJ kicks in making conditions better for strong tornadoes. Our team heading to memphis area by noon, around the time SPC thinks suppercells should be entering the area. Still long way off, but want to be in position near Memphis or Jackson by the noon hour with possibility of seeing and reporting on several Supercell chances. Plan ATM, chasing into Nashville area by early to mid afternoon. Good luck chasers.