2014-10-01 FCST: KS/NE/MO

[David Williams]

I started by checking the NAM for tomorrow's chase. Ottawa to Emporia area seemed a good initial target. The NAM paints 2100 CAPE (SB parcel), a nice turning hodo with mild to decent wind speeds, and a very acceptable EHI of 3 to 4. Deep moisture is also present through 850 mb level and a cap that's breakable.

Other ingredients looked to be in place... so I switched over to the GFS... what a mess. I kept checking the z time to make sure it was right. Everything takes a nose dive. CAPE 1000, the turning hodo wrapping up with a whopping 15 knot wind through the first few km. All indices flat line... Looking forward to rechecking things tomorrow morning. I want to make it happen, so I'm hoping the NAM is painting the more accurate picture.

 

[Todd Rector]

I am cautiously optimistic, preparing to blow the last of my vacation time tomorrow. Oye.

WWSTD? (What Would Skip Talbot Do?) heehee...

 

[Tim Supinie]

^ Skip has unfortunate initials for that acronym.

Greg Blumberg and I are looking at it, and we're trying to figure out the potential problems. The 00Z 12km NAM advertises a pretty solid low-end day. All the parameters are there, but none of them are incredibly spectacular. Could definitely see a tornadic supercell or two around sunset in the triangle bounded by Newton, Salina, and Topeka if the NAM verifies. Could be a potential after-dark tornado issue for a bit until things grow upscale.

One potential problem is that the 00Z GFS is still not nearly as optimistic as the NAM about the low-level wind profiles. 10 kts at 850 mb isn't worth 4 hours of driving for us. I'm not entirely sure the reason for the differences. I wonder if it has to do with the 850 mb low not deepening as much in the GFS because of increased static stability, but I don't seem to be able to find a whole lot of supporting evidence for that.

The surface moisture might also be a sleeper issue. The current trajectories across the central plains are from the high pressure in AR, which is not great in terms of moisture quality. There is some better moisture in south TX, but the problem there is weak winds, and it's going to have to get to KS awfully quickly.

The final potential issue is what happens with the broken line of storms currently stretching from northwest TX to southeast NE. It's currently not making a whole lot of forward progress, so if that sticks around longer than the NAM thinks it will, that could spoil our instability.