Monday, October 13, 2014

October 13th Severe Event

As of 915pm, storm reports pretty much show a hole in the MDT issued at 06Z which was focused on wind and sig wind. A comparison of the categorical outlook and the SSEO forecast I generate using UH tracks, showed a few interesting things:


1. A few ensemble members painted a bullseye across AR and others further south or east.
2. One member had more UH tracks in the FL panhandle than the squall line in and around AR.
3. Very little signal of severe weather in northern and central AL.
4. The NAM nest 4km, since the upgrade, produces very few tracks. [So different than the hi-res windows, I just cant explain this yet.]

The speed of the line and the squall lines'  UH track longevity are obviously in question.  I dont have the answers, nor the data to truly dig into it for each member. What is apparent is that the NAM UH magnitudes are much lower (lack of purple dashed contours indicates very few UH tracks with magnitudes exceeding 80 m2/s2).

I will post the verification tomorrow. However, this new SSEO (which we are all unfamiliar with) has some quirks. Going to need some other kinds of events to truly make an assessment of what this new ensemble is capable of. The last version took 3 years of data to say something meaningful about the winter months (Oct - Mar), while the spring/summer  (AMJ)/(JAS) could probably be meaningful after 2 years.