Recap of the April 9th VA/Carolinas severe weather event.

Well most of Saturday here in Central NC was cool and damp here at the surface, but yet we still had severe weather and storms how this is so, well for those who want to know Ill explain.
At 12z(8am local) we had a backdoor front push all the way to the Charlotte metro/upstate SC with most of central NC in a cool surface stable wedge.

Also the 12z SPC sounding showed a cool layer of air at the surface but just above that about850mb(5000ft) there was warm moist unstable air.

Along with some weak CAPE but lapse rates from 700mb to 500mb were 7c/km cooling with height also dry air was noted in a deep layer as well. Water Vapor imagery at 11:30am showed a short wave in the mid west with an MCV at the surface.

also note the SE ridge overhead. Fast forward a bit in time and by 4pm we started seeing severe storms show up over KY/VA and TN.

by 4:40pm we started to see supercells break out in W/SW NC with tornado warnings out.(heres base reflectivity and Velocity from GSP SC radar.

while still at the surface for central NC(all but Charlotte metro where dewpnts were in the 60s and temps in the 70s, this served as a focus for storms to train along.

but still storms were on going over the cool stable wedge airmass over central NC.

Where heres some answers as to why and how. First RUC analysis showed a 500mb short wave passing by helping to get lift going and the storms.

 

Sfc temps were in the 50s to upper 40s.

Along with the short wave and steep mid level lapse rates that produced a lot of lightning but also remember the 12z Greensboro sounding showed warm temps and good moisture at 850mb well heres a product called Theta-E all it is, is temp and dewpoint combined and the higher Theta-E the more unstable heres what we look at around 6/7pm.

Also Lifted index above the surface here very low and unstable

All and all this was a good severe weather event to learn something from and study for future setups hope you enjoyed.

More severe weather on the way.

After what seemed like an endless winter for people in the Mid West and Chicago, it looks like another severe weather event will come together for these areas starting on Sunday.
Lets take a look at the setup here and one thing I like to look at for convection is called Theta-E. Simply put this is a combination of the surface temperature and dewpoint. The higher the temp and dewpoint the higher the Theta-E and it is a good place to look for possible convection. Heres Sundays Theta-E map.

Next we need to look for CAPE, and in this case surface based CAPE.

Those two parameters alone can give you an idea if storms are possible but if a strong cap is in place or nothing to get lift going then your likely not to have much, but in this case we will have a lifting trigger and thats the cold front. Taking a look at the Helicity  values there will be some of that/Along with EHI values over 1 and that means a higher potential for tornadoes.

Also for supercells I look at the Sfc-1km shear and shear in this area of 30-40knts or greater means a higher likelihood of supercells. This is for overnight Sunday.

and 6hr precip overnight.

And with all this in mind NC also looks to get in on some severe weather by day3

Thats all for now Ill hae more later.

Monday night/Tuesday morning was a rough BUT exciting one.

A record breaking severe weather event unfolded from late Sunday evening April 3 to early Tuesday morning April 5 2011 with over 1200 reports of severe weather and a lot of tornadoes, one that was in Surry county NC. Also strong straight line winds raced across the Triad area with a few tornado warnings out also.
Severe reports.

Heres a few radar screen shots of the storms as they crossed into the Triad metro area.

Heres a close up of the Supercell that prompt the tornado warning in Davidson and Guilford counties.

Special thanks to Matthew East for the Gibson Ridge level 3 data.
Heres what the upper air sounding from Greensboro looked like 30 to 45mins before the storms hit at around 2:45am.

Just a prime severe weather sounding. The 00z sounding looked nothing like that the 6z above is from warm air advection and moisture advection.