WEATHERAmerica Special Statement, Wednesday Morning, February 28, 2007

[Larry_Cosgrove]

A relatively rare winter outbreak of severe thunderstorms and tornadoes is expected to unfold over the next 60 hours, affecting much of the central and eastern U.S.

Cyclogenesis is underway near Tucumcari NM, and this rapidly deepening storm will likely take a track close to a Liberal KS....St. Joseph MO....Keokuk IA....Green Bay WI arc through Thursday (with redevelopment near Columbia SC tomorrow night). This system is hybrid-type, negative to neutral-tilt evolving into a closed cA low near the Great Lakes by Day 3. Unusual for a storm at this time of year, the greatest warm-sector destabilization is forecast to occur after sunset this evening. Concurrent with the arrival of a strong jet stream velocity maximum at 250MB, increasing 500MB vorticity, powerful and pocketed spikes in UVV and a surface dry intrusion, there is a fairly high risk of tornadic supercells along and to the right of (by 250 miles) of the Interstate 35 corridor between Waco TX and Liberty MO. The danger here is that twisters and high-impact thunderstorms may strike while people are sleeping.

The severe threat continues on Thursday, with emphasis on two areas: the Ohio/Tennessee Valleys and the Gulf Coast. Further north, potent dynamics may offset marginal instability; in the Deep South, fast frontal lifting combined with mesoscale vorticity maxima and very buoyant (-6 to -8 LI) air may bring another round of damaging tornadoes. This convective array may turn into a frontal wave near the GA/SC border, then rocket north-northeast close to the Atlantic shoreline on Friday. While I expect the cities along Interstate 95 to be principally rain, warm air aloft and cold air drainage from a QC anticyclone could make things interesting in extreme N PA....NW NJ....much of NY north of Interstate 84....N CT....W, C MA....VT....NH....W, C ME and S QC. Compaction of the pressure gradient will almost certainly trigger strong winds from the Great Lakes into the Northeast and St. Lawrence Valley, making for a menacing situation for travelers and consumers of utilities.

A spell of cold air will follow across portions of the Midwest into the Eastern Seaboard this weekend with potential for snow showers and squalls to the lee of the Great Lakes.

[Martin]

Nice Discussion, Larry. Im right on the ice-border. It would be a wild one.

Looks like a decent flood scenario for NJ, CT, NYC areas aswell.