TWISTEX Field Operations for June 1, 2011

June 1, 2011 – 9:53 am

Currently in O’Neill, Nebraska

Past couple of days:

Chased a broken line of storms across northern Nebraska on May 30 (Monday).  Several storms were tornado warned, and noted two cloud/ground circulations near O’neill. The first circulation we watched had a brief multi-vortex structure near the ground, but pretty broad circulation overall.  This persisted for a minute.  The second circulation was related to outflow/inflow couplets along the gust front that persisted for several minutes where dust swirl was brought up to the rotating cloud base.  Certainly had the appearance of a Haboob afterwards.

Today:

Tough forecast today.  Looks like we may have storms in Southwest Nebraska, although the model data is sending mixed signals as to convection breaking out.  Some models show no thunderstorms over Nebraska, while others show storm initiation.  Moisture is creeping northwards with a developing strong 850 flow by early evening over western Kansas and Nebraska.  Due to the uncertainty of convection, we plan to hold in O’neill until there is some clarification on storm initiation

Tomorrow:

Another tough forecast call.  Strong mid level trough pushing through the northern plains late tonight with a developing, northward moving surface low with eastward trailing warm front would set the stage for supercell thuderstorms with possible strong tornadoes over North Dakota, possibly northern South Dakota.  The huge fly in the ointment is the very strong cap that is currently forecasted by most of the model runs.  This would render the strong possibility of a blue-sky bust tomorrow.  Otherwise, all other parameters seem to be in place for a big day. The big question is–do we go after this setup with the investment of expenses getting crews to ND?  Tough call.

Currently our plans are to have M3 and Probe hold somewhere in Northern Nebraska tonight after the chase(??) today, and make the call in the morning.  Interesting comparisons to the forecast struggle we had with the big Bowdle tornado day.  Some of the forecast parameters are similar to that big day on May 22nd (Trop flow, similar 500 flow, under a ridge, big worries about cap, etc..) of last year.

Future:

Or lack thereof…  Upper flow dissolves, surface flow weakens–looks like an extended down time that could last a week or longer!  Who knows–the long-term forecast solutions have been terrible so far–so we’ll keep the hope alive.

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