11/14/05 (late)-11/15/05 NOW: Midwest-Mississippi Valley

[Chris Sokol]

Tornado watch #862 issued for parts of Oklahoma, Missouri, and Arkansas:

http://www.spc.noaa.gov/products/watch/ww0862.html

Looks like a potential nocturnal outbreak of tornadoes is possible along and north of the warm front. Radar is still quiet at this time (in Central Oklahoma), but from the discussion I heard between a couple of the EM's here on the radio, storms are expected to rapidly develope over the next few hours.

 

[Jonathan Whitehead]

Just got back from SPC. Yes they were seriously considering issuing this watch about an hour ago. This doesnt surprise me. A surface low is beginning to form in the panhandles and will track ENE.
Look at the mesonet data at www.ocs.edu then look at Purcell VAD
http://weather.cod.edu/mcprofilerPRCO2.1hr.gif
Check out the directional shear

that stuff in NE OK is beginning to backbuild

http://weather.cod.edu/mcprofilerPRCO2.1hr.gif

http://weather.cod.edu/weather/public/raob...MN.skewt.23.gif

http://weather.cod.edu/hodos/ounhodo.gif

 

[Jonathan Whitehead]

have low level rotation on Tulsa radar just NW

also, explosion of cumulus right here in Norman

http://weather.cod.edu/analysis/paulradar/.pl?INX

 

[Andrew Khan]

Awsome couplet near Skiatook, OK.

 

[Sam Sagnella]

Very favorable conditions for supercells and tornadoes invof the warm front which is pushing through the OUN area as we speak. MUCAPEs are >1000 j/kg for pretty much the entire SErn 2/3 of OK, with juxtaposed 0-1km SRH values of 350-500 m2/s2. LCLs are a ground-scraping 400m over far eastern Oklahoma which is more than sufficient for a tornado threat. Initiation is already occurring along and S of the I-40 corridor east of the metro and the first SVR has just been issued for the storms near the Tulsa area. Bottom line is that I expect numerous tornadoes overnight from basically points east of OKC eastward through the PAH area with the greatest threat appearing to exist north of the FSM area.

 

[Jeff Snyder]

What I wouldn't give for this to be 1pm with full sun right now... Incredible low-level shear has developed (>600 0-1km SRH in eastcentral Oklahoma) as a strong low-level jet lays atop southeasterly or easterly surface flow. Dewpoints have risen rapidly across central and eastern Oklahoma, with OUN rising about 10 degrees in the past 3 hours. Temperatures have also risen south of OUN a few degrees in the past few hours. There was a time of very light winds after the sun set here in OUN, which helped the temp drop a few degrees this evening. If the surface winds pick up as the surface low deepens, any nocturnal inversion that is present may mix out, allowing for true surface-based convection. With surface temperatures holding steady or possibly rising, and surface moisture rising as well, surface-based instability may develop. Current SPC mesoanalysis is indicating ~1500 MUCAPE (elevated in this case) near and west of OUN, with 1000-1500 j/kg MUCAPE across much of eastern Oklahoma. As stated earlier, low-lever shear is very intense (40-50 kts 0-1km shear across central OK, yes that's 0-1km shear) Of course, if a storm is elevated, it won't ingest this rich low-level vorticity, so the shear will do little to the storm.

A look out the window about 10 minutes ago showed a TCU trying to go up over eastern OUN. It's been nice with the full moon, as it lit up some turkey towers very nicely earlier this evening.

EDIT: Surface winds have picked up to the 10-15kts range south of I40 in Oklahoma, so I think any nocturnal inversion that may be present may begin to weaken or mix out altogether, allowing for surface-based convection. Not much SBCAPE now, but >60 tds lurk just south of I40 and continue to head northward.

 

[nickgrillo]

This is the start of tomorrow, basically... Currently focusing on the convection developing along the warm front in deep southern IL and southward into western KY. At the surface, winds are backed to the south of the intensifying warm front -- pushing north slowly -- with the 60F isodrosotherm now pushing over PAH. Storms will continue to intensify as deeper moisture continues to be transported into the region -- leading to stronger low-level instability -- with a pocket of 500j/kg sbCAPE over western KY at 04z. Combination of backed surface flow and west-southwest upper-level flow has poised strong deep-layer vertical shear in excess of 40-50kts across warm sector. Low-level shear of 200-300m2/s2 0-1km SRH across warm sector indicates the potential for tornadoes with any storm that can ingest surface parcels. I'm currently watching the isolated convection that keeps developing south of the front in western KY... With the storm currently near Mayfield, KY showing an area of defined low-level rotation -- and is likely surface-based (and has been sustaining itself for the past 20 minuites and continues to intensify with each scan).

 

[Anthony Silver]

The cell entering the western section of Rogers County, OK looks to be undergoing some rapid intensification. Showing dBZ of 67, and 60% POSH ATTM. However those values increase with each update. That particular storm is also showing some signs of rotation, so I wouldn't be surprised to see this thing go TOR warned by the time it reaches Mayes County if it keeps intensifying.

 

[Nick Parker]

I would have to agree with Nick on that cell around Mayfield. It's been there for qutie some time now. Thats only about a 40 minute drive from here. (Go to school there everyday :roll: )

Had some pea sized hail fall around 10:00 as the warm front passed over me. Storm was Svr warned but fell apart as it moved off to my northeast.

 

[Chris C Sanner]

I'll agree with that storm over Rogers County. Looks like we may be getting ready to see the first tornado warnings of the evening here in Oklahoma. I'd hate to be a spc employee over the next 24 hours or so....

Edit: Just noticed the Torn Watch is outside of the slight risk area on the western end after I looked at the SPC overview graphic....

 

[Anthony Silver]

Appears now the Rogers County, OK cell has decreased in intensity somewhat. Looks like POSH as gone down considerably (20%) and the dBZ is now down to 61. The other cell of interest appears to be over SW Craig County, OK, just NE of Chelsea. Looks like that one is trying to pick up some intensity, and may be putting down some fairly large hail.

 

[Anthony Silver]

I'll agree with that storm over Rogers County. Looks like we may be getting ready to see the first tornado warnings of the evening here in Oklahoma. I'd hate to be a spc employee over the next 24 hours or so....

Yeah, the SPC and NWS offices are going to have their hands full the next several hours I'm afraid.

 

[Jeff Snyder]

To demonstrate the incredible shear in place tonight, check out the profilers in the area:

Purcell (central OK): http://weather.cod.edu/mcprofiler/PRCO2.6min.gif
Haskell (eastern OK): http://weather.cod.edu/mcprofiler/HKLO2.6min.gif
DeQueen (western AR): http://weather.cod.edu/mcprofiler/DQUA2.6min.gif
Lamont (northern OK): http://weather.cod.edu/mcprofiler/LMNO2.6min.gif
Bloomfield (extreme se MO): http://weather.cod.edu/mcprofiler/BLMM2.6min.gif

Those are incredible wind profiles, all supportive of strong/violent tornadoes. Again, unless a storm can ingest the air in the lowest 2km (in other words, be surface-based or very near surface-based), it won't experience nearly the same shear as would otherwise be the case. With very weak (or non-existant) SB-instability, I don't think we'll see high-end tornadoes, but if a storm encounters a pocket of locally higher instability -- watch out.

 

[Chris C Sanner]

To demonstrate the incredible shear in place tonight, check out the profilers in the area:

Purcell (central OK): http://weather.cod.edu/mcprofiler/PRCO2.6min.gif
Haskell (eastern OK): http://weather.cod.edu/mcprofiler/HKLO2.6min.gif
DeQueen (western AR): http://weather.cod.edu/mcprofiler/DQUA2.6min.gif
Lamont (northern OK): http://weather.cod.edu/mcprofiler/LMNO2.6min.gif
Bloomfield (extreme se MO): http://weather.cod.edu/mcprofiler/BLMM2.6min.gif

Those are incredible wind profiles, all supportive of strong/violent tornadoes. Again, unless a storm can ingest the air in the lowest 2km (in other words, be surface-based or very near surface-based), it won't experience nearly the same shear as would otherwise be the case. With very weak (or non-existant) SB-instability, I don't think we'll see high-end tornadoes, but if a storm encounters a pocket of locally higher instability -- watch out.

Good thing (but bad for us chasers) this isn't in the middle of the day here, I'm afraid that won't be the case for those under the gun tommorow. My hope is that everyone in the threatened areas tonight is aware and able to get to shelter if the situation presents itself..

 

[Ronnie Bradley]

There is a severe t'storm warning out for Baxter Co, in northern AR right now. On radar, it looks to have a bit of rotation on its SE side but not much. It's displaying HP characteristics as well. It has a solid rain core that is reading 59 dBZ on the KLZK radar (I know, the radar site is not ideal to view the storm...).
In my area, it was previously foggy out but the fog has lifted, the full moon is bright and the wind is calm, though that may change within a couple of hours.
Velocity mode on radar shows strong low to mid level winds out of the SSW. It hasn't mixed down to the surface yet.
Searcy is around 60 F. LR's temp is 70. Apparently, there is a bit of an inversion over my area but if the surface winds begin to blow, it should mix out and temps should rise a bit, along with the dewpoints.
update: baxter county warning lifted; winds beginning to blow a bit out of the SSE. Distant lightning still being seen off toward the north.