7/20/04 NOW: NE, SD, MN, IA

[Larry J. Kosch]

Action Closer to O'Neill

NWS has issued a SWW for cell SW of O'Neill:

459 PM CDT TUE JUL 20 2004
THE NATIONAL WEATHER SERVICE IN NORTH PLATTE HAS ISSUED A SEVERE THUNDERSTORM WARNING FOR HOLT COUNTY IN NORTH CENTRAL NEBRASKA UNTIL 600 PM CDT

AT 455 PM CDT, NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM. THIS STORM WAS LOCATED NEAR AMELIA, OR ABOUT 22 MILES SOUTHWEST OF O'NEILL AND MOVING EAST AT 25 MPH. THE SEVERE THUNDERSTORM WILL BE NEAR CHAMBERS AROUND 520 PM CDT

Where are you going, Mike??

 

[Larry J. Kosch]

TX, OK, NE Panhandles and KS

Mike P. it looks like you may have to add TX, OK and NE Panhandles and KS to the thread title. Storms are firing up in those areas too!! :shock:

Update: looks like the two boundaries I mentioned in my previous posting has come together SW of O'Neill NE. And that's producing a E-W line of storms. That's not good. There's another boundary just north of Ainsworth NE that looks like its feeding the storms near Spencer, NE. 8)

 

[nickgrillo]

Well, the slight risk does include Northern Illinois and activity is beggining for fire up in that area. A SVR has just been issued for a little, yet potent looking storm in Jo Davies County, IL.

AT 523 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR
GALENA...OR ABOUT OVER GALENA...AND MOVING EAST AT 10 MPH.

..Nick..

 

[nickgrillo]

WOW! That storm is extreme NW Illinois and really picked up. Look at Velocity... it's also showing some decent rotation!

[edit] At 5:49pm: Spotters reported 2" hail from this storm in Galena!

..Nick..

 

[mikegeukes]

As of 6:00 CDT

The SVR TSTM WRNGS for Garfield, Holt, Loup
Counties no longer in effect, only report from the
LBF office has been of 0.88 inch hail. in Boyd County.

Boyd County has a SVR TSRM WRNG till 645 PM CDT.
movement of storms southeast at 5 mph.

WW 659 SEVERE TSTM: IA IL WI has been issued until 10PM CDT.
Reports out of Jo Daviess County so far 2.00 inch hail.

Mike

 

[Jeff Snyder]

WOW! That storm is extreme NW Illinois and really picked up. Look at Velocity... it's also showing some decent rotation!

[edit] At 5:49pm: Spotters reported 2" hail from this storm in Galena!

..Nick..

Tilt 1 Reflectivies in the mid-50s and mid-30 to low-40 VILs (per the DVN radar) are certainly nothing to write home about... Rotation, what there is of it, remains quite weak as well. While it does look decent on the La Crosse radar, I'd be hesitant to use that radar much for this storm given that it's about 120 miles from it. Meanwihle, the DVN radar is only about 60 miles away, which means it's getting a much "closer" view of the storm, and it's lowest tilt scan is scanning lower in the storm than the La Crosse radar is... The only thing that I "like" about this storm that can show that it is severe is the depth of the higher reflectivities, with even Tilt 4 showing mid-upper 50s reflectivities...

Heading west.... current SPC mesoanalysis via the RUC continues to show a highly unstable environment from southeastern SD south and eastward, with indiciations of MUCAPEs >7500 near OMA currently. However, weak midlevel flow is creating weak 0-6km shear, which is likely the reason that the current storms are struggling to organize. For any storm that can develop sufficient organization, the combination of 3500-5500 SBCAPE and 200-250 0-3km helicity (and ~100 0-1k helicity) would seem to support a tornado risk, especially as storms translate eastward into the higher mean boundary-layer RH (and related lower LCLs) near FSD and points eastward.

 

[nickgrillo]

Well, it went from looking like a devoloping Supercell w/ 2" hail reported and it currently looks like a piece of crap with .5" hail possible. :?

How fast good things come to an end, huh?

A blue box has just been issued for S. WI/N. IL thou.

..Nick..

 

[mikegeukes]

As of 8:53 PM CDT
Latest Mesoscale Discussion for SERN SD through NERN NEB
mentions cap, slow movement of storms, and onset of nocturnal cooling.
http://kamala.cod.edu/spc/0407202315.acus11.html
http://www.spc.noaa.gov/products/md/md1743.html

Sunset Times for cities in and or near the Tornado Watch.
851 PM CDT Omaha NE
857 PM CDT Sioux City IA
900 PM CDT Norfolk NE
902 PM CDT Sioux Falls SD

SVR TSTM WRNGS tonight for SD: Davison, Dewe, Douglas
Hanson, Hutchinson, Lake, Mc Cook, Miner, Potter, Walworth,Counties.

DBZ of 61, VILS of 78, Echo Tops of 61 K as of 2323 Z
1.75 inch so far in Davison and Hanson Counties.

Latest 00Z Soundings from tonight.
http://weather.cod.edu/wx/public/raob/abrskewt.GIF -Aberdeen
http://weather.cod.edu/wx/public/raob/mpxskewt.GIF -Minneapolis
http://weather.cod.edu/wx/public/raob/oaxskewt.GIF -Omaha

Highlights from South Dakota:
3.00 inch hail in MIner County
70 mph winds in Lake County

Mike

 

[nickgrillo]

Nice little cluster also in NW Wisconsin! Check the Duluth radar.

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
BURNETT COUNTY IN NORTHWEST WISCONSIN
WASHBURN COUNTY IN NORTHWEST WISCONSIN

..Nick..

 

[Jeff Snyder]

A very nice storm has strengthen considerably in the past few scans near Mitchell, SD. This monster supposedly (per the FSD radar) tops >61k feet and VILs near 80. This isn't too much of a surprise, since a loop of the last few hours of Sfc moisture convergence shows that the strong convergence has remain nearly stationary near and immediately west of Mitchell. Indeed, this has likely locally weakened the cap and obviously supplied sufficient convergence for sustained initiation. If the storm can establish itself for a while longer, it will likely organize into a decent supercell, considering the low-level shear and instability nearby... Only wishing it can hurry up east a little bit to get into a better LCL and low-level shear environment, as evidenced by the FSD VAD profile, which shows a nearly ideal veering profile.

EDIT: I didn't update my mesoanalysis... The storm near Mitchell likely has about 5000-6000 SBCAPE to deal with and 250-300 0-3k helicity, making EHIs >9 ... If only mid-levels were a little stronger...

 

[Jordan Manderfield]

A very nice storm has strengthen considerably in the past few scans near Mitchell, SD. This monster supposedly (per the FSD radar) tops >61k feet and VILs near 80. This isn't too much of a surprise, since a loop of the last few hours of Sfc moisture convergence shows that the strong convergence has remain nearly stationary near and immediately west of Mitchell. Indeed, this has likely locally weakened the cap and obviously supplied sufficient convergence for sustained initiation. If the storm can establish itself for a while longer, it will likely organize into a decent supercell, considering the low-level shear and instability nearby... Only wishing it can hurry up east a little bit to get into a better LCL and low-level shear environment, as evidenced by the FSD VAD profile, which shows a nearly ideal veering profile...

I'm watching this storm on radar and it sure has exploded over the last hour or two my swift wx pro indicates rotation and 2 inch hail

 

[Bob Hartig]

Any of you Michigan chasers noticing the cell up by Mount Pleasant? At the moment, it's looking supercellular, and it's taking a right turn relative to other storms on the radar.

(I know this is outside the discussion, but where else do I put it?)