Tag Archives: severe weather

Five years since the Ides of March Outbreak

KCLX Level II radar image at 8:29 PM March 15, 2008, as seen through GR2Analyst. A supercell thunderstorm near Moncks Corner had just produced a tornado in the Strawberry neighborhood (between Moncks Corner and Goose Creek) while a forward flank downdraft from a supercell heading over southwest Charleston County was entering downtown Charleston (where I was living at the time). Radar estimated maximum hail size of 1.5 to 2 inches with these storms in addition to intense rotation.

KCLX Level II radar image at 8:29 PM March 15, 2008, as seen through GR2Analyst. A supercell thunderstorm near Moncks Corner had just produced a tornado in the Strawberry neighborhood (between Moncks Corner and Goose Creek) while a forward flank downdraft from a classic supercell heading over southwest Charleston County was entering downtown Charleston (where I was living at the time). While the tornado threat was greatly reduced near the coast, spotters reported quarter-size hail with storms near Johns Island, while baseball-size hail later fell on Hilton Head Island.

Today marks five years since supercells packing tornadoes, strong straight-line winds, and large hail ravaged South Carolina and Georgia in an incredibly unusual atmospheric setup for mid-March known as the Ides of March Tornado Outbreak. (Typically, our most favored time for tornadoes is April and May, according to a National Weather Service research study.)

The March 15 outbreak introduced me to the concept of a Particularly Dangerous Situation Tornado Watch, an enhanced type of severe weather watch more common in the Plains and in Dixie Alley (MS/AL). (Indeed, it was this outbreak which triggered my most intense study into meteorology as well as watch and warning dissemination and spurned on the creation of @chswx a few weeks later.) Here is the archived watch, PDS Tornado Watch 120, at the Storm Prediction Center website.

Three supercells from this event stand out for me: one spawned a EF1 tornado in the Strawberry mobile home community, causing $250,000 in damage and injuring several people (source). It struck a little too close to home for comfort; my parents live just a few miles south of Strawberry in Goose Creek and were very fortunate to dodge that bullet. A second supercell over Hollywood brought very strong winds to where I was living in downtown Charleston at the time — believe it or not, it was the first classic supercell thunderstorm I had ever been in! I didn’t see any hail but the wind was fierce — reminiscent of Hugo videos — with driving heavy rain. On Hilton Head Island, the third supercell produced baseball-size hail at the Hilton Head Airport causing severe damage to aircraft.

In the end, tornado damage up to an EF3 rating was found in several parts of the state (particularly on NWS Columbia’s turf). The Charleston metro area dodged a big bullet as a seabreeze had moved through earlier in the day which helped cut off needed surface-based instability for tornado formation closer to the coast.

Level III image from the afternoon of 3/15/2008 as supercells move through the Midlands of SC.

Level III image from the KCAE WSR-88D captured on the afternoon of 3/15/2008 as supercells moved through the Midlands of SC. (Please excuse the radar branding. Old inside jokes don’t hold up well in historical contexts…)

For more information, including a great technical discussion of the ingredients that led to such a rare outbreak, read NWS Charleston’s summary of the event; I also recommend their research paper (PDF) as it gets really deep into the meteorology. It also explores the challenges of issuing storm-based severe weather warnings in such a widespread severe weather situation (especially since storm-based, polygon warnings had just rolled out).

Fortunately, this March has been very calm and I’m pretty sure we all prefer it that way.

Tornadic Roadblock

This video was shot Tuesday evening by Drew Cavanaugh in central Florida, where several tornado warnings were issued due to strong rotation on radar and reports of funnel clouds, including this video. Nothing like driving down the road to see a tornado kicking up ahead of you to perk you right up.

Hat tip to more people than I can name over on Google+.

Amazing readings from the mesonet station in El Reno, OK

Oklahoma Mesonet readings over the last 24 hours. Can you spot the tornado impact?

Oklahoma Mesonet readings over the last 24 hours. Can you spot the tornado impact?

Get a load of this meteogram from the Oklahoma Mesonet in El Reno, OK, tweeted by Base Velocity, LLC. Not only did it measure a 150 MPH wind gust around 4:30 PM, it also recorded a pressure drop to 940 millibars and a complete loss of solar radiation around that time — suggesting it was pitch black outside at the time of the tornado. I’ve seen early reports on Twitter suggesting pretty serious damage there. Here is a Doppler base velocity image from around the time of the tornado strike. Extremely strong couplet in play. I hope people heeded warnings and protected themselves from what appears to be an extremely violent tornado.

First solid severe event of the spring in the books

3D view of a severe thunderstorm over Beaufort, SC on March 27, 2011. Image generated by GR2Analyst.

3D view of a severe thunderstorm over Beaufort, SC on March 27, 2011. Image generated by GR2Analyst.

The first severe weather event of the spring is in the books for the Lowcountry. Hail was the primary factor, with numerous reports of large hail, with a report of baseball-size hail near Rincon, GA and tennis ball-size hail in Port Royal, SC (just south of Beaufort; check out TheDigitel Beaufort for pictures). There were a few isolated wind damage reports, but hail was definitely the story. One tool I like to use to examine the aftermath of a storm event is the IEM Cow, an unofficial tool developed by the Iowa Environmental Mesonet that groups issued warnings with storm reports (if there were any for that particular warning). Here’s what the Cow says about today’s event.

The hail core that dropped the baseball-size hail continued out of Rincon and basically followed U.S. 278 for a time, dropping golf ball-size hail on Hardeeville and Bluffton before weakening as it traversed the north end of Hilton Head and went offshore. Fortunately for our cars, the core of the storm stayed to our north (I live mid-island); we got a brief dose of heavy rain and a very chilly downdraft but not terribly much more than that.

IEM chat rooms I’m monitoring today

I’ll be watching three weather chats today: WFO Charleston, SC, WFO Columbia, SC, and WFO Greenville-Spartanburg, SC as a threat for severe weather unfolds later today and into tonight. A reminder: These are not official NWS chat rooms — there won’t be any forecasters in there, but iembot will be there to relay watches, warnings, and other products from the various forecast offices as they are issued.

Pure Luck

Base reflectivity image of severe thunderstorm over Hilton Head Island

Base reflectivity image of a severe thunderstorm over Hilton Head Island on July 10, 2010.

This severe thunderstorm, referred to as extremely dangerous by the Charleston National Weather Service, was about as intense as advertised, and was quite a scare for one driver, as this NWS storm report illustrates (emphasis added):

CHS: 1 W Hilton Head Island [Beaufort Co, SC] law enforcement reports TSTM WND DMG at 05:34 PM EDT — large oak tree fell on car at intersection of jenkins island road and hwy 278. driver uninjured.

Yeesh. Glad the driver’s OK. Here’s a roundup of today’s storm reports — was a windy one out there on Tybee Island.

A doozy of a weather day ahead

In advance of a doozy of a weather day, I’ve spent a portion of my evening revamping the Charleston Weather blog. I’ve installed the latest P2, Automattic’s excellent real-time WordPress theme, and I’ve also (with any luck) enabled PubSubHubbub for posts to the blog. Weather information is exactly what the real-time web is designed for, I think — tomorrow may be a great test of that. So, especially if you’re in Charleston, follow the blog tomorrow along with the alerts we’ll have on Twitter, Identi.ca, and Facebook. Hopefully things will turn out better than the strongly-worded alerts have been telling the story, but it’s tough to say.

Recapping last night’s severe weather

I’ve done up a quick recap of last night’s severe weather over on the Charleston Weather blog. The storm report map was sourced from the Iowa Environmental Mesonet website. They’re very progressive (geotagged storm reports using the Google Maps API, a Jabber room that relays products directly from LDM, etc.) and ridiculously useful in a pinch. I like ’em a lot, and might need them again tomorrow.

Hunker Down!

Severe weather season roars back to Charleston today. I’m in “hunker down” mode here, monitoring all sorts of varying weather information. Here’s how to keep up:

  • On Twitter, I’ll live-tweet the storm event at @chswx. If you just want warnings and forecasts, I recommend @CharlestonWX. Also see @weatherwatches for advance notice of potential watches. Don’t forget local media, as well, including Rob Fowler, Josh Marthers, Joey Sovine, and the Live 5 Weather Team.
  • I’m uploading radar images periodically to radar.charlestonwx.com. There’s an animation script which gives you 10 frames and many Level III products to play with.
  • If time permits, I’ll do some writing with more detailed analysis at my new weather blog. Given the fast pace of these storms, blogging may be somewhat prohibitive. (It’s much easier to blog a hurricane than it is a springtime weather event.)

Despite all this technology we now have, your best defense is to have a NOAA Weather Radio and make sure to heed all warnings that come down from the National Weather Service or other emergency management officials. Remember, the Internet is a great tool, but is not intended for life-or-death decisions. Stay safe out there!