May 17, 2009

5/17/09: May 20th (Possibly the 19th) Looks Like First Day

The WRF-NAM is now in range of the early period, and still corroborates that there might be just enough low level moisture for storms to develop in an environment with a looped hodograph, albeit short (~35 knots of shear) over northern third of Nebraska, eastern Wyoming, and southern South Dakota on Tuesday (19th), with similar to better conditions the next two days..

So this appears to be our last "relax" day. (Last night we saw the movie "Angels and Demons.")

Then the surface pattern slowly evolves southward, with slightly better dew points as air comes around the horn, and the pressure pattern redistributes higher dew points over the southeast, leading to non-tranditional trajectories. So by Thursday or Friday we will be in north central KS or southwest Nebraska.

By the way, I have had complete agreement with whomever has been writing the 4-8 Day thunderstorm outlook for SPC, who also has highlighted the fact that the pattern could generate severe/rotating thunderstorms in the Tuesday-Thursday period. One of those forecasters also mentioned high based supercells, but all concluded the overall risk is too small to include in a 30% outlook at this time. That's exactly the way we feel.

We may be looking at blue sky, but we also might have rotating storms.