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After 4 days in self-imposed dry dock, Virginia Tech Storm Chase 2009 finally leaves from Blacksburg on Thursday morning. Unlike mariners soothed by calm seas, we will be searching for the violent thunderstorms in the wide spaces of the central U.S., primarily the Great Plains region that parallels the Rockies hundreds of miles to the east from Canada to Mexico.

This looks to be an especially challenging trip. Strong winds aloft, typically dipping and diving across the nation, have retreated to Canada, more like late June or even July rather than late May. The rich Gulf of Mexico moisture that typically moves unhindered northward over the prairies has been stymied, first by a chilly Canadian air mass sinking southward and now by a persisent low pressure system whirling counterclockwise, pushing north winds into the Gulf.

Thunderstorms will probably be widespread this weekend over much of the central and northern Plains as weak disturbances tap moisture primarily of Pacific origin, having surged northeastward in a "monsoon" like fashion across the Desert Southwest, a phenomenon also more typical of mid to late summer. The challenge for us will be finding regions where rotating severe storm structures will be possible. The best chance of that now appears to be in the northern High Plains of western Nebraska, eastern Wyoming, southwestern South Dakota and perhaps eastern Colorado, where east winds blowing uphill may be able to pool enough moisture for convection under moderately strong winds aloft that can give some storms a spin.

Throughout next week, there is little hint of any large-scale weather pattern change, but additional cold fronts from the northwest and disturbances from the west ... plus at least a modest return of Gulf moisture ... might be able to trigger a few severe storms here and there. No outbreaks appear in the offing, but we're not really looking for one: Just one special supercell.

For more on Storm Chase 2009, please also visit the Virginia Tech Storm Chase blog linked here.

2009 chase team members:
Anthony Phillips, junior, Snowville, Va., geography (student trainer, returnee from 2005 trip)
Andrew Smith, senior, Mechanicsville, Va., civil engineering (student trainer, returnee from 2008 trip)
Erik Ferryman, senior, Chesterfield, Va., geography
Nathan Horne, junior, Spencer, Va., geography
Samantha Huddleston, sophomore, Roanoke, Va., engineering
Jiyoung Jeon, senior, Seoul, South Korea, geography
Phillip Long, junior, Newport, Va., geography
Andrew Martus, junior, Fredericksburg, Va., geography 
Ashley Shim, junior, Berryville, Va., biology
Kevin Shutta, freshman, Waltersville, Md., business 
Brian Smith, senior, Salisbury, Md., aerospace engineering
Byron Wiedeman, senior, Vienna, Va., physics
David Carroll, Virginia Tech meteorology instructor, trip leader
Kevin Myatt, Roanoke Times/roanoke.com weather columnist
Bob Oliver, visiting assistant professor, geography, Sarnia, Canada
Jim Stroup, Tech photographer