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

[Mike Peregrine]

Mesoscale Discussion no. 1740 has been issued for parts of Nebraska, South Dakota, Minnesota and Iowa with radar reflectivities beginning to indicate possible convective initiation west of O'Neill, Nebraska in a CU field running visibly in a SW-NE oriented line on satellite.

http://www.spc.noaa.gov/products/md/md1740.html

Discuss nowcasting for today in this thread.

 

[Mike Peregrine]

Current target area radar

BREF out of FSD:
http://weather.cod.edu/analysis/paulradar.pl?FSD

BREF out of OAX:
http://weather.cod.edu/analysis/paulradar.pl?OAX

Current 1km satellite:
http://weather.cod.edu/analysis/analysis.1kmvis.html

 

[Anthony Petito]

They have also issued a Tornado watch* (EDIT) for that same rough area.

http://www.spc.noaa.gov/products/watch/ww0657.html

*Sorry

 

[Mike Peregrine]

Noteworthy watch language includes:

VERY UNSTABLE AIR MASS IN PLACE ACROSS WATCH AREA WITH CAP BECOMING VERY WEAK WRN PORTION. RAPID DEVELOPMENT OF SEVERE THUNDERSTORMS EXPECTED IN AREA OF BEST LOW LVL CONVERGENCE VICINITY NEB/SD BORDER W OF YKN. VEERING SHEAR PROFILES SUPPORT SUPERCELLS WHICH WILL ENHANCE POTENTIAL FOR VERY LARGE HAIL AND ISOLATED TORNADOES.

 

[Mike Hollingshead]

In O'Neill now about to head west. Lots of elevated crappers getting blown off that boundary. Hoping for better organization soon on the more western boundary half way between O'Neill and Ainsworth right where they apparently merge.

 

[Mike Hollingshead]

Still sitting in O'Neill.....what a mess!

 

[Mike Peregrine]

That cluster is looking very messy presently - - - but some of the storms further south are starting to get better organized ... stick it out a bit and hope nothing fires closer to Yankton (though you should be able to make it up there with no prob if you need to). Hopefully the mess will get its act together and structure-up rather than remain an elevated junk-fest.

 

[Larry J. Kosch]

Look for Action in the SW

I would think the action would be better to the SW of O'Neill, perhaps down by Burwell or Broken Bow. The NWS radar shows two distinctive boundaries. The group of storms west of O'Neill is on the northern boundary, while the group of storms down by Burwell and Broken Bow is on a separate boundary off to the south.

I have a gut feeling the southern boundary will interfere and perhaps cut off the inflow to the northern boundary as the storms grows bigger. Particularly if the southern group of storms gets going eastward. I'm also thinking along the line of a "Tail-End Charlie" situation setting up down by Broken Bow.

GOES-12 VIS SAT is showing the southern line is extending itself all the way back to North Platte. Eventually I think the northern group of storms will struggle until they move forward and get on the southern boundary.

Just putting my thoughts in. Any questions??

8)

 

[Glen Romine]

... stick it out a bit and hope nothing fires closer to Yankton

Why would you not want convection near Yankton? Seems like convection juxtaposed to that are would have a more realistic chance of becoming supercellular. Shear there is much better, both deep layer and near surface, as well as sitting on the tip of the greatest instability axis. Guess I want to defend this region as it is near my target - well my target was a short distance NW of Yankton anyway, and I'd still support that region as having the best chance for supercells this evening.

Thanks in advance,
Glen

 

[Mike Hollingshead]

I should be driving north and get up into SD now..... But, I will give NE it's change...lol. Affraid if this mess organizes it's going to start too far south. I want *some* mid-level flow. Hope was something in SD would drop south. Not so sure about venturing down towards Burwell....ug. Have hopes something around Spencer yet, but if that goes south it will have problems with this crapfest. Then again it is possible anything good wouldn't HAVE to be a south mover.

 

[Mike Peregrine]

Why would you not want convection near Yankton?
Thanks in advance,
Glen

I WOULD want convection near Yankton if I were there ... but here's what happens in a situation like this ... a big mess starts early down to the south ... a chaser sits there waiting for it to organize itself and get its act together, and meanwhile, something fires an hour and a half to the east in a better wind environment that immediately goes up and starts rotating. Situations like this can end up becoming really frustrating if a person isn't really careful and considers all the options ... that's actually what I was intending when I said that -

So hopefully since Mike is already in position this current stuff will figure out what it wants out of life really quickly ... that, or else if anything does go up further east, he can make it over there in time.

 

[Larry J. Kosch]

Spencer Not Looking Good

Just looked at NWS radar out of North Platte. That cluster of storms near Spencer does not look good. Rather disorganized and the cloud tops are getting blown to the SE.

I do see one good storm getting organized just to the NW of Burwell. Looks like two storms merged together, that would account for its good size. Not seeing any kind of rotation yet.

Still I would put my bet on the storms to the NW and W of Burwell. I would not discount the storms near O'Neill just yet. The separate cells are starting to move together now.

I did some NOW casting earlier back in May for a storm chaser. I saw a storm near Concordia KS that was kicking up a strong rotation. I tried twice to convince my chaser to go south. He didn't and he missed out on a tornado-fest on that day.

Don't miss this one!!

Update: That storm NW of Burwell was severe storm warned:

443 PM CDT TUE JUL 20 2004
THE NATIONAL WEATHER SERVICE IN NORTH PLATTE HAS ISSUED A SEVERE THUNDERSTORM WARNING FOR GARFIELD COUNTY IN NORTH CENTRAL NEBRASKA LOUP COUNTY IN NORTH CENTRAL NEBRASKA UNTIL 545 PM CDT

AT 440 PM CDT, .NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM. THIS STORM WAS LOCATED 13 MILES NORTH NORTHWEST OF BURWELL, AND MOVING EAST AT 20 MPH.

 

[Zach Bailey]

Looks to me like things are starting to get better organized. That middle storm is starting to develop some rotation, so maybe it's not all crap...though right now it looks more kidney-bean-ish (HP) than classic.

 

[mikegeukes]

North Platte mentions storms are moving east at 20 mph in their Short Term Forecast, and also a Severe Thunderstorm Warning just been issued for Loup and Garfield County, movement of the storms east at 20 mph. VILS of 79, Echo Tops to 58K, currently on the latest radar at 2140Z.

Holt County now under a Severe Thunderstorm Warning until 6pm CDT.
Storms moving East at 25 mph.

Mike

 

[Glen Romine]

Gotcha Mike P., I guess I should have seen it as sarcastic - a little slow sometimes. Well, maybe another hour of sifting and it will become clearer which cells have a chance do something more 'interesting'.

Glen