3/7/2004 REPORTS: Eastern USA

Dan Robinson

A surprise severe weather event occured in North Carolina, Virginia, and
West Virginia Sunday evening. My brother Matthew in Raleigh, NC gives this report from TenTen Road in southeast Raleigh:

We just had our first severe thunderstorm of the year
here. It was 60 degrees about an hour and a half ago
and now its 43 degrees. There wasn't too much
lightning, but it was extremely windy. The severe
weather bulletin said gusts of up to 58 mph. The
power actually went out for about and hour locally. I
managed to capture a small bolt:


I saved this velocity image that shows a strong couplet over Hertford County, NC (Murfreesboro) at 9:36PM EST.


Several low-topped storms moved across WV late in the afternoon, but the big event was in SE VA and NE NC.

I see a ton of Purple Haze and plenty of dealiasing errors but not finding the couplet - where are you looking?
I seen that several tornado warnings and severe t-storm warnings were out for your area yesterday. Looking at the velocity product you have, I see what appears to be a nice couplet, though it looks much too broad to support any real tornadic conditions. I have zoomed re-focused the area I believe you were talking about, but tell me if I am wrong -

[Broken External Image]:http://www.waveformpc.com/meso.gif

Looks more like velocity folding to me. The outbound/inbound is oriented perpindicular to the radial. This is a sign of either a) folding or B) convergence/divergence. For a true couplet, (in this case where the radial is oriented from NW to SE) you would want the cross from outbound/inbound to look like:


Just my take.

I agree with Aaron... I does appear perpendicular to the radial, which leads me to believe divergence, since you have green (towards the radar) next to red (away from the radar), BUT this interface is perpendicular to the radial... This of course does not seem definative, since there is the 'left' in/outbound interface that is along a radial, which may denote rotation... It just seems that the strongest winds in-/outbound are along the east-west interface ....

This is a sign of either a) folding or B) convergence/divergence.

That does make sense.... At the time I noticed the surface winds in front of and behind the squall line in this area were nearly head-on (SE out ahead, NW behind).

After taking a second look at this I see the issue with the region of sharp contrast in velocity being too broad, as compared with others from known tornado events.