March 8th 2010 "cold core" event.

Image by cloud9tours. This image is important because it shows important structure. Which helps us evaluate what exactly we are dealing with here. This cell is actually more reminiscent of a classic supercell. And is probably more reflective of a somewhat higher cape higher shear event than a true cold core low type setup. So besides the classic cold core setup we are dealing with something of a hybrid. Temps were in the low 60s with dewpoints in the 50s. But with the extremely cold mid level temps cape values were a little higher than usually. Plus we had some very intense wind profiles! Overall nature always has the ability to surprise us. Even when we think we are starting to figure things out!

Surface analysis at 2107z right around the time the first towers were going up along the boundry. The boundry being what was labeled as a pacific front. But was really a dryline/occlusion due to surface heating. The occlusion was a dryline/warmfront. The surface heating was very important in raising the temp/dewpoint spread which slowly transforms the airmass into something very different than a cold airmass type frontal system. Which for reasons not well understood helps in the types of storms that are produced. Instead of Linear forcing, and subsequent forced convection. We have spotty non-linear convection. Which could be due to a bulge in the dryline/occlusion. But a bulge wasnt evident and convective initiation seemed to be due to surface convergence in key areas where good CAPE was present along with almost no CIN whatsoever. The greater convergence at the surface is also a key function of the compact system allowing the backing of surface winds just ahead of the surface low. Aiding in a triple point type convective situation. Or so it would seem.
Whats also important is the fact this is a vertically stacked system, which is common for cold core type systems. The system is compact and tight. Due to the dynamics, rapid cyclogenesis takes place at the surface which aids in the winds backing and increasing in strength near the low and just ahead of it. This can help speed up the occlusion process. Which in turn is important for convergence. This convergence pushes air in and up helping to fire storms.

The Hammon mini-supercell underway here on radar and satellite. Whats interesting and usually highly important is the dry slot wrapping around the low. Surface heating had a chance to augment the airmass and help with destabilizing the atmosphere ahead of the 500mb low. Whats also important is you can see dust being kicked up by the strong surface winds on the satellite image.

Modified RUC sounding showing some fat CAPE even for a cold core event. Due to the steep lapse rates and very cold upper level temps! The hodograph also shows some pretty decent shear. Interesting moisture profile.

RUC surface analysis. Confirming setup is prime for development and already underway. Alot of convergence along the dryline/pacific front, warm frontal occlusion. It also confirms what we were seeing on satellite with the dust being kicked up. 30 knots down in west central TX behind the dryline kicking up some dust!

RUC 500mb analysis for 23z showing strong negatively tilted closed cold core low. With temps at and around -20 C. Strong Jet max rounding base. This as you can see is a very compact, vertically stacked system which is important in cold core tornadic events. This system is supplying alot of shear and alot of upper level forcing!

Unlike alot of cold core events some parameters started to show up right around the time the Tornado was occurring. Although by this time its far too late and still doesn't really highlight an area of huge concern. Cape values around 1000 j/kg, co located with high SRH values (but still not that high) had painted a nice EHI bulls eye around the Hammon area.

Feel free to comment with questions and critiques afterall this is a learning process for all of us. And I certainly dont know much in the way of meteorology, I am no expert. So feel free to comment!