Chase Day 23 - SD/NE/KS

[Paul Sherman]

Big Big day coming up, all models all over the place at the moment, will decide in the morning and see where that warm front has meandered to, some say SD/NE Border others further south, one thing is for sure it could be a very big day with all parameters maxed out.

 

Paul S

[nsrobins]

A number of issues with this set-up, some that scream 'severe-end event' and others that suggest an early line-out.As Paul says the clever money is on the WF and latest runs suggest it to lie further North at 20Z than previously modelled. Storm motion level winds though will keep any cell parallel to it so a rooted cell moving due east along the front will almost certainly develop strong rotation given the scary helicity.This is the hodo from the 05Z RAP for just north of Grand Junction, NE:

 

http://www.twisterdata.com/data/tmp/scratch/models/processing/RAP_255_2014060305_F17_41.5000N_98.5000W_HODO.png

 

A long vertical start then looping a long way right and then back - very significant directional AND speed shear and the shape you're looking for for tornado potential.

The caveat for me is the timing and clearing of early convection and the possibility that retreating junk interferes with the inflow region. A lot can change and targeting should be based on position of WF on obs although I wouldn't stray too far east and north and keep the DL play in mind should junk prevail further east.St Paul, NE and I'll be there by 1pm local. 

[Boro Snow]

i will be watching with interest later when i finish work mindue i dont finish till 10pm so hopefully plenty of action left, stay safe guys 

[nsrobins]

I am already thinking that a slight more North is required, still on the 281 but towards Wheeler County, NE.For a few hours conditions look favourable for a few discrete supercells with LCLs indicating low-base mesocyclones.

 

Note metro areas of Souix City and Souix Falls under the gun this evening.

 

Additional: 08Z RAP plonks insane deep-layer EHI of 11+ over N C Nebraska at 22Z. Presumably just on or south of the WF boundary. Phew!  Should clutter from current complex across NW NE clear by 16Z I'm guessing an upgrade to HIGH may be in order.

Edited June 3, 2014 by nsrobins

[Dan the Man]

Omaha NE is probably not a bad place to be. CAPE going off the charts, around 1500-3000. TORCON of a SEVEN. Wow.  

 

Seriously dangerous day ahead - stay safe folks.

Edited June 3, 2014 by Dan the Man

[nsrobins]

The fickle synoptics continue to tease.The surface boundary/WF currently lies along the I80 in S C NE, about 100 miles further south than modelled. The earlier clutter is clearing away eastwards leaving a significantly unstable environment in it's wake with 70F+ dps. I am now looking to shuffle a bit south of St Paul down towards Grand Island/Kearney - expecting initiation around 18Z with quickly dissolving cap.A big day - stay safe.

 

PWO issued:

http://www.spc.noaa.gov/products/outlook/pwo.html 

Edited June 3, 2014 by nsrobins

[nsrobins]

Sticking my neck out a bit here but with the surface WF hanging back a bit in S NE now, subtle OFBs from the earlier complex could well come into play regards interaction with the WF.Just had a check on hodos for my target area and they're off the scale to be honest - huge clockwise deeply looped profiles that scream intense and rapid rotation right up through the cell.Good luck guys - and hold tight.

[Paul]

PWO (public severe weather outlook) issued by the SPC

http://www.spc.noaa.gov/products/outlook/pwo.html

 

[IanM]

We're lunching in grand island while waiting on developments. Things are looking pretty dangerous as the derecheo passes through. Could be embedded tornadoes moving at 50-100mph, so we won't be chasing those...

[NL]

Right in the middle of the latest Tornado watch.

WWUS40 KWNS 031818WWP7TORNADO WATCH PROBABILITIES FOR WT 0207NWS STORM PREDICTION CENTER NORMAN OK0111 PM CDT TUE JUN 03 2014WT 0207PROBABILITY TABLE:PROB OF 2 OR MORE TORNADOES                        :  40%PROB OF 1 OR MORE STRONG /F2-F5/ TORNADOES         :  30%PROB OF 10 OR MORE SEVERE WIND EVENTS              :  80%PROB OF 1 OR MORE WIND EVENTS >= 65 KNOTS          :  70%PROB OF 10 OR MORE SEVERE HAIL EVENTS              :  50%PROB OF 1 OR MORE HAIL EVENTS >= 2 INCHES          :  40%PROB OF 6 OR MORE COMBINED SEVERE HAIL/WIND EVENTS :  90%&&ATTRIBUTE TABLE:MAX HAIL /INCHES/                            : 2.5MAX WIND GUSTS SURFACE /KNOTS/               : 80MAX TOPS /X 100 FEET/                        : 500MEAN STORM MOTION VECTOR /DEGREES AND KNOTS/ : 29045PARTICULARLY DANGEROUS SITUATION             : NO

[samadamsuk]

stay safe team - enjoy the chase and we always appreciate an update whenever you can. Looks like some CU getting agitated down in North Platte from the latest sat - dominator 2 team are there at the mo -

[Boro Snow]

TVN is starting to come alive

[samadamsuk]

yeah certainly is. going to ba an interesting night on tvn with chasers trying to stay ahead of the Derecho!

[samadamsuk]

yes looks like towers just starting to go up over North Platte from what I can see -

[Paul]

Stream is live btw, currently it's not the most amazing view (a brick wall), but I'm sure it'll improve soon

 

http://www.netweather.tv/index.cgi?action=chaselive;sess=

[samadamsuk]

cool - streams working well.

[Boro Snow]

Stream is live btw, currently it's not the most amazing view (a brick wall), but I'm sure it'll improve soon

 

http://www.netweather.tv/index.cgi?action=chaselive;

yes i know mate i am watching that aswell 

[nsrobins]

There you go - upgrade to HIGH risk E NE into IO for the bow/derecho.Tornado chances still the same in area previously highlighted.

[lorenzo]

Storm Prediction Centre release High Risk warning.

 

 

Looking harem scarem...

 

SPC conducting a live Q & A on Twitter at present.

 

Guidance on probabilities for SPC Issue of forecast

 

http://www.spc.ncep.noaa.gov/misc/SPC_probotlk_info.html

Edited June 3, 2014 by lorenzo

[Paul]

Latest briefing from Paul.

 

[samadamsuk]

Hey Neil. Yes makes sense - I see there was a 100mph wind report a couple of hours ago on that Derecho - looking even more intense now.. watch out Omaha!

[nsrobins]

Hold fire - elevated cells N NE forecast and will probably not produce but the OFB from this region - clearly seen on visible - is likely to initiate storms between Lincoln and Broken Bow in next hour. 

[Paul]

Stream is back live after a few connection problems 

http://www.netweather.tv/index.cgi?action=chaselive;sess=

[nsrobins]

Tower and first radar return about 10 miles SSW Broken Bow.

[lorenzo]

Clarkson, NE right now, wild cloudscape.

 

Latest satellite image.

 

Blair, NE.. wow pic..

 

 

Edited June 3, 2014 by lorenzo