Saturday, April 10, 2010

Severe Weather/Chase Forecast: April 11th

I have been watching this potential severe weather setup since getting home from chasing on Monday.

A nice deep trough sits off of the west coast and thanks to ridging in the east, is not going anywhere very fast. Out ahead of this system, return flow is a bit deflected by the ridge, but it sill advecting moisture northward into the central high plains.

At the surface, a leftover, a slowly frontolosizing boundary is draped from SE Colorado into the panhandles and then northeastward into Kansas. The southerly flow should begin to push this boundary northward tonight while it continues to slowly dissipate. Still, however, it should exist as a point of convergence tomorrow and will have to be watched.

Where the boundary slowly retreats to the north, moisture should pool (and deeply according to some model forecast soundings), which will enhance instability. Obviously a problem will be capping (EML being the buzzword as of late), so areas of surface convergence will be important in finding actual storms that go up.

The NAM runs have been all over the place as to where the highest areas of instability and inhibition are so it is difficult to trust at this point. The GFS has been more consistent with placement of surface features but not with capping. So, it's hard to trust either of these models as an absolute solution.

It appears that two vehicles of us Colorado chasers will be heading out tomorrow and the plan is to closely monitor surface observations and the rapid-update models.

I really enjoy days like this as they certainly are a challenge. When it comes down to it, you really have to rely on the subtleties in the observed surface network and one's ability to detect them.

For what it's worth, the local WFOs are not talking much in the way of severe and the SPC has only mentioned very conditional risk. You'd think I'd learn my lesson from Bustzilla on Monday! At least the GFS and NAM are both breaking our precip this time, albeit in sporadic, random locations!

However, these days can be very rewarding, especially when many other folks aren't out there cluttering up the roads.

Will post an update tonight after the 0Z models come in.


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