Jeff Snyder
EF5
{Apologies for hogging this thread... I'll take a break to give others a chance after this post}
Actually, I'm not sure I'd recommend concluding that the movement of the low precluded it from being produced by a negatively-tilted upper-level trough. With a strong baroclinic boundary, the most intense warm-air advection (and resultant pressure falls, which directly influence the movement of the low) will often occur to the east or northeast of the low... If the primary baroclinic boundary is located in a WNW / ESE fashion (i.e. the warm front lies to the ESE of the low) the max WAA will likely occur to the east or ene of the surface low. Add in a couple other factors (such as the vort max swinging through the base of the trough), and I'd say that the ENE motion of the surface low could very well have fit in with a typical scenario of a neg-tilted trough aloft.
As a cyclone matures and begins to occlude, you'll often see it move more northerly as the warm air advections wraps all the way to the north or northwest of the surface low. This happens quite a bit with occluding coastal storms in the eastern US. As the low fills, it may continue to move toward the area of max low-level warm-air advection, which may indeed be to the north or northwest even.
Because of the intensity of surface lows often produced by negatively-tilted troughs, in addition to the favorable shear profiles often present in such an upper-level pattern, some of the biggest and baddest tornado and severe weather outbreaks have been associated with negatively-tilted troughs. It's certainly a good feature to be able to recognize, and you'll probably read a lot of AFDs from various NWS offices mention either positively- or negatively-tilted troughs in terms of unfavorable or favorable severe weather / tornado setups. Of course, a pos. tilted trough doesn't mean that a setup will be garbage, just as a negatively-tilted trough doesn't guarantee an outbreak.
EDIT: I see where a potential flaw exists in my reasoning... A deep, negatively-tilted trough is characterized by relatively high heights to the north of the vort max (since the trough is oriented in some degree from the NW to the SE, heights indeed increase to the north of the trough axis, moreso towards the base of the trough). High heights, in turn, are related to warm mean thermal profiles... This would indicate that the primary warm front would probably not be located east of the low, but more to the northeast or even more to the north of the low. The max WAA-causing-max-surface-pressure-falls process would then occur more to the NE or NNE of the sfc low, not so much to the ENE. I would say, then, that DPVA provided significant pressure falls to move the surface low east-northeastward. In addition, was there widespread precip to E or NE of the low as it developed and moved? Latent heat release can contribute to surface pressure falls, which may have also aided in moving the cyclone to the ENE....
I haven't looked at an upper-air map from that day, so this is an educated guess. I probably should before I say much more, in case the upper-air map doesn't look anything like what I'm imagining in my head. For example, the presence of a couplet jet feature may have proven significant (which it often does in "bombogenesis").. Maybe Glen could chime in, since there may be more complex processes at play that I don't know too well (e.g. I'll be learning IPV in grad. synoptic class this spring).
