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03/08/06 NOW: Central/Southern Plains

Going to get the ball rolling on a nowcast thread with the issuance of tornado watch number 39 ... http://www.spc.noaa.gov/products/watch/ww0039.html

Covering most of eastern Kansas and western Missouri.

Cumulus fields in NE Kansas and NW Missouri have begun to firm up nicely and are even beginning to send back reflectivities in southeast Kansas. Looks like initiation is imminent or even underway now.
Echo returns in southeastern KS don't appear to be surface based given the speed and appearance on sat. But - more likely initiation near the boundary over the KC metro. Still most interested in the northwest portion of the watch box - tornado threat in KS looks prett meager to me right now - but something interesting might get rooted in the narrow band of moisture just north of the warm front (where moisture increases north of the front) slipping back into extreme northeast KS - say in and around St. Joseph. Otherwise - think the best chance for good storms will be roughly along a line from Atchison KS to Columbia MO.

Definitely would have been moving northeastward from my previous 'virtual' target of Emporia. Continued diabatic heating across the moist sector is contributing to strengthening boundary layer instability (with SPC mesoanalysis showing SBCAPE >1500 j/kg in northeast KS) and weakening CIN -- as indicated by zone of Cu in visible sat developing across northeast KS. Negative factors...

1. The veering of boundary layer flow to a more southwesterly direction invof surface cyclone could decrease storm relative inflow
2. The decreasing SR inflow is contributing to decreasing 0-1km SRH in zone of strongest instability -- with <150m2/s2 SRH observed overlapping >1000j/kg SBCAPE -- except in a small region between Topeka and Kansas City -- where stronger 0-1km SRH is owed to more backed surface flow

At any rate, deep layer vertical shear and instability are more than sufficient for organized supercells -- with favorable SRH for an isolated tornado or two -- particularly with any storm that can ingest the stronger streamwise vorticity in the region of more backed surface flow along the warm front. As of now, I'd position myself in Kansas City -- where their should be a concentrated risk for tornadoes in the region of backed low-level flow and deeper low-level moisture near the warm front -- with forced ascent provided by zone of enhanced low-level convergence near the triple point.
It appears from vis sat that the Cu in Brown and Doniphan counties are making an attempt ... the loop is showing them build fairly rapidly in the counties just west of STJ. Additional development remains possible in Platte County, Missouri and even Wyandotte Co., Kansas, where towers look like they might try to go for it as well -

EDIT - my brother is telling me that an updraft west of St. Joe, near Atchison is going straight up and looks like it's going to make it ... he mentions that its about to start anviling out -
Despite cloud cover it looks like the area near Wichita Falls into Oklahoma along a well-defined portion of the DL may soon see intiation. Little cinh remains with 1500-2000 j/kg SBCAPE and decent moisture convergence. Just north of this area is where the kink in the DL setup is forecasted. Effective shear will support supercells but there isn't much in the 0-3km or 0-1km layer for tornadoes yet. With increasing forcing I'd expect some possible intiation in next 1-2 hours.
The cell east of STJ is at about 40 dbz now, but Andy is under it, and tells me that the UL winds are still pushing the towers over - this cell is in Doniphan county, just to the east of St. Joseph, about to cross the river into Andrew County, Missouri. Still looks to me like more possibilities exist to the south -
SPC Mesoanalysis product seems slow to update

We've experienced these problems in the past.

Perhaps we should send an email. Anyone have a good link for email contact?
I get the feeling looking at the instability axis that the cell near St. Joseph won't be able to make it. I think we need something a little further south or a cell on that can take a right turn againt the WF.
It's still intensifying a bit over Andrew county, but I don't like how quickly its moving north - - - I think Scott is right - we need a cell to fire just a bit further south that will ride the boundary and not cross over too quickly. The stuff around Platte City may be worth watching -
Radar is showing the cell to be dying as it moves off the boundary to the nne. Maybe its just cycling. The boundary appears to be stalled running nnw to the ese through St. Joe. Maybe another cell will fire yet.

MD out for Dryline in nc TX

EDIT: Well I switched from Topeka to EAX it now looks like the cell is still hanging in there, but not real impressive.
It's a wait and see at this point, my chase partner and I are watching closely and waiting for initiation. We're not far from the dryine and from Denton county Tx we can quickly reach central Ok or estrn Tx if need be. We haven't decided on a target yet we're going to let the storms make the first move and then we'll head out Our strategy should work provided the activity fires within reach and not 300+ miles away.
The huge pile of cirrus that has formed over OK in response to the wave forcing has become a large mass of cloud in which there is almost no breaks. We could have certainly done with the insolation. I noticed it cloud over here in OUN by around 1.30pm.

Watch out for those easterly components in S-cntrl OK.

I am waiting here in Ardmore, OK with great wifi access for convective initiation along the dryline. A majority of the OK chasers are here as well including Aaron Kennedy, Shane Adams, Mickey Ptak, Gabe Garfield and others. 20z OUN sounding shows 1500 J/kg CAPE and no CIN with bulk shears in upwards of 75 kts in south central OK. Winds appear to be starting to back via the OK Mesonet -- just a radar watching waiting game considering the thick cirrus shield across the entire area of interest.
Well, St. Josepheans (MO), if there's game this afternoon, it looks like you've got it just northeast of you. The dryline is punching in pretty fast, and it looks like a cell split is holding together. Good luck!
Sitting here at home with wonderful Wi-Fi access as well waiting on storms to fire. Looks like we could be in for a long evening here in Southern/SE OK

EDIT: Long being time wise, I'd bet on the weather making it like that too!
cell has formed in Throckmorton county along dryline but remains week so far. VIL was building but we shall see. It seems if there is ever a chance of severe storms in this area... Throckmorton usually gets it.

I may head South on 79 if this cell keeps buidling out of Wichita Falls. It will be moving into Young and Jack counties which are very hilly and lots of oaks ;-p
Been watching cell in Throckmorton county for past 30 minutes; looked possible for a while, but has weakened somewhat past few scans. Magic spot in Texas seems to be first or most likely to be active regardless if odds are long or short; just stick any boundary in the area and seems something usually fires there.
Initiation has just taken place as an apparent line of cu (hidden by the CI on satellite) just passed over the retreating dryline NW of OKC.

A cell now displays a 40dbz core already northeast of OKC. On radar, it is evident that the line of cu passing over the dryline NW and west of OKC will likely initiate shortly and unzip southwestwards down the dryline.

I am hoping that this isn't the beginning of our big linear sausage.

Appears there may be a confluence boundary east of the dryline in TX near Stephen county, seen when DYX was in clear air mode 45 mins ago. Just sat through some rain here in Ardmore... Winds have backed nicely north of here in Paul's Valley and Ada (with SSE-SE winds and 10F dewpoint depression, meaning locally lowered LCLs), with real cells maturing in Lincoln county and northern Oklahoma City. I'm a little concerned with storm mode... Shear vectors are out of the SW right now, which is nearly parallel to the dryline, particularly in central OK.

Substantial pressure falls are occurring in western OK and TX as strong large-scale ascent commences ahead of the vort max in NM. With the max pressure flals to the west, isollabaric forcing would indicated that our winds will begin to back east of the dryline... KTLX shows the dryline nicely moving back to the NW through OKC, not that that concerns me too much since I'm in Ardmore. Some echoes continue near Throckmorton and into Palo Pinto co. TX, but I assume those are elevated in origin. 20z OUN sounding showed no cap, though 18z DFW/FWD sounding showed substantial capping remained. The current light precip is falling through the capping layer, which should be resulting in evaporative cooling, which may actually help us remove the cap. Of course, it'll cool the surface temps as well, but continued strong southerly flow should help bring back warmer surface air.
The cells ne of STJ seem to have crossed the boundary. The right cell briefely popped some 60dbz. I'd be looking at the cell developing ne of KC, which has awhile to run in the good air.
THe NWS has issued Tornado Watch #40 in effect until 11:00pm ct for NE Ok, and Central Ok.

WOU0)." -SPC text product.
That Oklahoma cell is nothing compared to the one in SC Iowa. Second day in a row where a severe storm has popped up in the state. 60dbz and a little bit of shear showing up on that one, though I don't expect much to come of.
As Jeff noted, appears a confluence zone NE of Abilene may be enhancing convergence in Throckmorton and Palo Pinto county area. Peculiar the way appears in composite reflectivity mode on DYX radar.
Sure looks to me like the cirrus shield/less than full insolation and Cap have prevented these cells from taking off. They have had every opportunity to do so but continue to fizzle both in OK and the Ft. Smith, AR area. Unless something goes very soon, this convection potential will be a bust.