2011-04-24 FCST: OK/TX

[Doug Drace]

Im kind of suprised nobody has started a thread on this day yet. Not a whole lot of time to get into the major details regarding Sunday, but the over basics include a sharpening DL from SW OK down into NW/C TX, a WF across C OK, and a 50 knt 500 mb flow. High Cape environment good low level directional shear along with a breakable cap. I wouldnt be suprised if somewhere in SPC's 30% Sig Severe zone at least a small Moderate Risk was added. More details later when im off work....Happy Chasing!

 

[Chip Redmond]

NAM is spreading out the moisture quite a bit and not really placing a dryline in OK or NC TX, however it does have a sharpening dryline in southern TX, but its wayyyy down there. The frontal zone seems to be the focus of convergence tomorrow with CIN eroding by 21z. PW's are 1.5"+ and this will allow for HP supercells that will creep along at about 25kts or so. 0-3km helicity is above 300 and low level, 0-1km is still around 200 because of backing winds. GFS is taking a better liking to the dryline and has it much sharper than the NAM. With the cap also suggested to break around 21z as well, initiation along the dryline is possible. PW's are slightly less and could allow for classic supercells to develop along the dryline if it should hang farther west.

If that dryline does push eastward and sharpen, definitely a strong area of convergence at a triple point like setup in southern OK and northern TX. Directional and speed shear are indictive of rotating storms. The upper level 90kt+ jetstreak could help by arriving a bit earlier but right now it isn't going to move over the southern Plains until well after dark. Putting aside the vague outlier of the NAM tomorrow, there is a definitely potential for tornadoes tomorrow. It is a setup I favor, but it just has to be Easter...

Chip

 

[Aaron Dooley]

I was surprised also as it looks better in some ways today than the last two down here. I almost started one but I'm glad someone else did. Torn between the Red River target and further west and south towards WF again...

Im kind of suprised nobody has started a thread on this day yet. Not a whole lot of time to get into the major details regarding Sunday, but the over basics include a sharpening DL from SW OK down into NW/C TX, a WF across C OK, and a 50 knt 500 mb flow. High Cape environment good low level directional shear along with a breakable cap. I wouldnt be suprised if somewhere in SPC's 30% Sig Severe zone at least a small Moderate Risk was added. More details later when im off work....Happy Chasing!

 

[Greg McLaughlin]

The NAM has done a poor job handling surface features the past couple of days. Obviously its impossible to resolve the surface features until tomorrow. Either way, this bears watching, and if something closer to what the GFS is showing verifies, tomorrow could be a good day around the SPS area. Hopefully convection doesn't over-initiate.

 

[Bob Conzemius]

I guess not too many people forecast any more because these forum tend to be pretty quiet prior to severe storm days (compared to 10 years ago). I'm not finding great wind profiles for tornadoes. The deep layer shear looks sufficient for supercells, but the low-level shear looks a little anemic in most of Texas.

The better low-level shear looks like it will be up closer to Oklahoma, but there's less CAPE there, so I'm in a bit of a quandary about what to do. The storms will certainly look nicer to the west and southwest, but I think tornado potential is better farther northeast. However, this is all based on the NAM, which, others have remarked, has handled surface features relatively poorly.

-Bob

 

[Bill Hark]

Although not a tornado outbreak day, I think there is a decent enough chance for tornadoes and severe storms to justify an Easter chase if no family obs. The 00Z GFS just came out and I like the area of 50 kt SW 500 mb winds in central Texas and small bullseye of 60 kt winds by 18Z. The 0Z Nam is not quite as bullish (mostly 40 kt) though I have been leaning to the GFS lately. Both the NAM and GFS show south to southeasterly 850 mb winds in southern Texas. Although not required for tornadoes, I have seen more photogenic tornadoes with south or especially southeasterly 850 mb winds. Both models also show backing surface winds for southern Texas though the predicted wind speeds are not as much as I would prefer. Predicted CAPE is also sufficient from 2500 to 3000 in a small area per NAM. Dewpoints will be in the 60’s. I am most concerned about predicted SRH, currently around 150 for my target area. Right now, I would start the day in Junction Texas. Disclaimer, I am sitting at home since I can’t chase until later in the season. Good luck to those who are out.

Bill Hark

 

[Doug Drace]

Looking to chase the same general area as yesterdy along the stalled boundry in N TX today. Dynamics look very similar, hodo's decent, along with decent 0-1/0-3 EHI's from south of Wichita Falls to the HWY 82 cooridor in NC TX. Ysterday paid off, today just might as well Good Luck Chasing Everyone!

 

[Tim Marshall]

Will play the stationary front in Texas again today. Best convergence appears to be along and north of I-20 west of the DFW metroplex. Picked the target town of Mineral Wells to start.

 

[Aaron Dooley]

Will play the Brownwood to ABI area as a preliminary target and possibly further west if things look good.

A large bend in the front will provide enhanced focus for development
3500 CAPE near Brownwood
40-50 knots of shear 0-6km coming into area now
25-30 knots of shear 0-1km
850-500 crossovers are good
LCL's at 750m
LFC at 1000-1200 just NE of area
SB LI's -9 to -10, -10 SW of area closer to DL/TP
mid-level lapse rates at 8.5 (big hail again)
Td's upper 60's, temps at 75/77~
best moisture convergence in same area ratios 25-10
EHI 0-1 now at +3

Expect initiation of some sort in next 1.5 hours

 

[Doug Drace]

Our initial set up area is going to be around the St Jo to Bowie area in N TX. The stalled boundry is draped through that area to the SW, and Hi-Res models relatively consistant at initiating scattered convection from the Red River north of the St Jo area to the SW by 5pm. There are also relatively good road options in just about every direction from there, as well as a way across the river...though I dont think much will happen in OK today as far as surface based storms, with the possible exceptions being Marietta to Ardmore and points east. My other concerns are the scattered convection initiated by 5pm on HRRR looks junky, with the only real obvious supercell not firing till late, around 7pm well to the SW of the N TX area, and todays instability doesnt look as attractive as yesterday did, with a lot more in the way of low cloud cover throughout N TX. At any rate, we'll be headed out around 3pm for the St Jo area and adjust accordingly from there.

 

[RMacDonald]

Just ran my 19Z Severe Analysis. As of now, showing the cities of De Queen, AR, McAlester, OK, Dallas, TX , Little Rock, AR, Hot Springs, AR, Allen, TX, Mena, AR with the highest instability rates. Surface CAPEs are running 2,100 (J/KG), 0-3KM Shear at 30 knots, 0-3KM SRH are pretty good at 288 m/s, and the 0-1KM EHI are high at 3.1. Seeing potential gust around 70-75knots and hail size up to 1.5" in diameters. A bit better tornadic environment across the AR areas with slight higher lower lever shear amounts. Uploaded analysis http://smartwxmodel.net/severe.pdf