11/24/10 FCST: KS,OK,TX,AR,MO

[Mike Smith]

Surprised no one has started a thread for tomorrow. Here goes...

SPC has a slight risk that I think looks good but is a little too far east. The 18Z NAM has a 165 kt (!!) jet along the KS-OK border at 00Z tomorrow.

At 01Z this evening, a warm front extends from MLU to SEP that will move north tomorrow and provide a focal point. This evening's 00Z soundings show plenty of moisture and instability. SHV has PW of 1.27" and forecast CAPE of 1,457j.

The SFC low should rapidly deepen around END with the warm front extending to around JLN by late afternoon and early evening.

My only concern is initiation. I think the warm front will be able to trigger storms via convergence and, once triggered, there is a likelihood of supercells.

So, take the SPC forecast and move it about 60 miles WNW and extend it into extreme northeast Texas and I think that covers the threat area. If I had to narrow it down, I'd keep a close eye on NE OK.

 

[James Gustina]

I'd agree with ya Mike. The deep layer shear on this one is pretty impressive looking, round 50 knots or so with some really strong speed shear going on in Eastern Oklahoma. Dewpoints should stay in the 60's if elevated crapvection doesn't tamper too much with the environment early on. Also looks like some nice southerly flow with that strong jet you were talking about. Overall a good late year setup.

 

[Jesse Risley]

The current visible satellite imagery is showing some breaks in the ongoing cloud cover over parts of central and EC Oklahoma. I think one of the biggest deciding factors today will be how much instability actually materializes given the ample SFC - 1 km shear profiles AOA 45 kts, 0-1 km SRH values AOA 250 m2**s2, ample LI and warm air surging north ahead of the main system.

As far as tornadoes are concerned, forecast hodographs do show ample directional shear for tornadoes to remain a bona fide possibility, though speed shear profiles indicate the storms will be moving at respectable speeds across some partially unfavorable terrain, if everything doesn't amalgamate into a linear show rather quickly. H85 - H5 mean RH profiles <= 40% begin working into the region after 17z, which IF more destabilization in the wake of clearing does materialize, along with SFC dewpoints reaching the lower to mid 60s as far north as the I-44 corridor, that could help to boost CAPE values enough to foster adequate buoyancy for the other atmospheric parameters to work with. SPC SREF depicts 100 mb ML CAPE values >= 750 J/KG nosing into EC OK by 21z.

Right now EC and NE OK, along with far SE KS, appears to be among the better threat areas once initiation occurs, if instability parameters do materialize. Storms will probably move quickly into SW MO, where instability parameters may remain favorable given ample 2m dewpoint values working into the region, along with some breaks in the current overcast conditions.

EDIT: The 12z rawinsonde from SGF is available, showing no shortage of shear across the region: http://www.spc.noaa.gov/exper/soundings/10112412_OBS/SGF.gif

 

[Jeff Piotrowski]

Today OK!!

Based on 15Z data the WF is moving into Northern OK at this time. The tornado conditions are rapidly setting up from central -NE OK.

Per the 12Z RUC/NAM expect storms to fire 18Z in Central OK rapidly moving ENE 45+ into NE OK. Tornados are likely across NE OKLA!!

I would not be surprised if SPC was to bring the 10% tornado area all the way back into Tulsa on the new 16:30 Update.

 

[Trey Thee]

Based on 15Z data the WF is moving into Northern OK at this time. The tornado conditions are rapidly setting up from central -NE OK.

Per the 12Z RUC/NAM expect storms to fire 18Z in Central OK rapidly moving ENE 45+ into NE OK. Tornados are likely across NE OKLA!!

I would not be surprised if SPC was to bring the 10% tornado area all the way back into Tulsa on the new 16:30 Update.

Thats exactly what they did.

This looks like one of the better setups for us since the April or early May time frame.

If I go out I'm thinking Claremore/Vinita would be a good area to setup. Initiation looks to be just back to my west (I'm in Owasso). I am concerned about storm speed given the terrain. 45kt is one thing in western OK, its another up here and around the Grand Lake area. Anyone have any additional thoughts?

 

[Jeff Snyder]

I don't have much time to do any forecasting and won't be chasing today, but the forecast storm motions may make things very difficult. The right-mover supercell storm motion from the 18z OUN sounding is 50 kts, courtesy of ~55 kts at 700 mb and 80 kts at 500 mb. If the winds just off the sfc can back a bit more in the primary target area, the storm motion may end up around 50 kts. With 0-6 km "shear" (vector wind difference) 70-80 kts, I also wonder if there will be excessive dry-air entrainment along cloud edges that may discourage updraft sustainability. Little turning of the wind through the low- and middle-troposphere may result in primarily cross-wise vorticity, but the intensity of the flow just off the surface is significant (Haskel profiler showing 45-50 kts at ~ 1.2 km AGL, and Neodesha is showing ~50 kts down do nearly 1 km AGL). Even though mid-level lapse rates aren't particularly steep, there is seasonably high moisture (60-64 F Tds) in the warm sector in eastern OK and extreme SE KS / SW MO, and current vis sat indicates agitated Cu E of SPS - OKC - W of BVO (where cirrus obscures possible Cu). 16z HRRR isn't showing anything worth mentioning, but, again, I haven't paid attn much. If I were to chase today, I suppose I'd stick near the turnpike / I44 out of consideration of the fast storm motions and the fact that the I44 corridor is seeing some insolation bewteen the Ci shield to the N and some more BKN Cu or stratocu to the S.