Roll Clouds

AWIPS animation of visible satellite on Friday, December 16.
AWIPS animation of GOES-East visible imagery on December 16, 2016. Roll clouds are very evident in this imagery. Also note the hard edge of the cloud canopy of the cool air wedge in place around Lumber City, GA.

Yesterday’s skies were particularly awesome, with lots of roll clouds on display. Shea Gibson of WeatherFlow shared some photos from the ground as well as a great explainer on how the clouds ended up like they did over on Facebook.


Timelapse: One Storm Dies, Another’s Born

A severe-warned thunderstorm that produced quarter-size hail in Hanahan missed my part of West Ashley to the northeast this afternoon. However, this thunderstorm produced an outflow boundary which intersected with the seabreeze over the Charleston/Dorchester county line to generate new showers and thunderstorms. These thunderstorms pushed east and dropped a brief amount of rain and a little wind before moving on to the southeast.

Summer is the best.

Personal Projects Weather

The Charleston Weather Blog returns again

Return of the #chswx blog!

An issue with nginx rewrite rules would not let my image uploads be great, but that’s all settled now. I’m looking to transition away from so much reliance on Twitter and switch to more of a live blog format during events (though weather Tweets won’t go away). The P2 theme lets me create a fully integrated environment to receive storm reports on a thread, which is awfully nice. Keep this page bookmarked as I’m going to try out a few cool things there. (Eventually, the whole site will run on WordPress — stay tuned.)


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.

In Pictures Weather

Ice, ice, baby

Map of ice accumulations prepared by the National Weather Service in Charleston.

Map of ice accumulations prepared by the National Weather Service in Charleston.

This winter just gets weirder every day, it seems. Monday brought on a fairly significant icing event in the Charleston area that, for a change, did not involve Smirnoff. Roads were closed, schools were closed and delayed even today, and black ice is still a possibility for the inland counties. (For the record, we were shut out of winter weather for the most part on Hilton Head Island, though there was a report of ice just west of here in Bluffton.) Temperatures will remain well below normal for the rest of the week before moderating this weekend in advance of another frontal system. Personally, I’ll be glad to get back to severe weather season, though this winter has given me an excellent hands-on education in winter weather.

In Brief Technology

Collecta’s blog shows citizen news reporting in action

The Collecta blog has posted a neat case study about the Charleston flooding that happened a couple weeks ago, and how people used Collecta to tie together information from places like TheDigitel and @chswx (the Charleston Weather Twitter account I run) to keep up to date on the situation. I’m a big fan of Collecta, and an even bigger fan of the power of real-time technology to enable community journalism, so this case study is a fantastic. Also, if you haven’t read it already, Christopher Zorn’s account of his usage of Collecta to guide his family through the floods is another great example.

In Brief Weather

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,, and Facebook. Hopefully things will turn out better than the strongly-worded alerts have been telling the story, but it’s tough to say.

In Brief Media Appearances Weather

Nice press for @chswx in Charleston City Paper

Charleston City Paper’s Lindsay Frost has a cool Twitter piece (jokingly subtitled “Obligatory ‘Hey, Ever Heard of Twitter?’ News Story”) which has a cool mention of the @chswx weather account. It’s really fun to see @chswx get some traction as I think we do some pretty cool stuff with it, especially as hurricane season gets into gear. Also featured in the article are Brian McGee, chair of the College of Charleston Department of Communication; Lyn Mettler, president of Step Ahead Web Strategies; and Andrew Edahl, a College of Charleston student.

Technology Weather

My weather experiment on FriendFeed

The latest foray into my meteorologically-themed social media exploration is the Charleston Weather FriendFeed group, designed with some automated aggregation of Charleston weather-related tweets in mind, but also designed as a point for folks to share their weather stories and reports. It seems like a strange, nearly too-narrowly focused topic for a FriendFeed group, but I see it as an important proof of concept stemming from some goals we set for Charleston news reporting in March.

You may remember the Charleston news hashtag summit-of-sorts. The meeting brought together media members, active Lowcountry bloggers, and concerned Twitter citizens. We hashed out a series of tags that would classify tweets accordingly. There are tags for news (#chsnews), breaking stories (#chsbrkg), and the like. The goal of using these — and really, any hashtag — is to bring related content together so people can filter their streams accordingly. These tags have met with moderate adoption; I’ve personally seen some tags more than others. One of them, #chswx, is one focus of my FriendFeed group.

Site News Weather

New beginnings for

One of my focus areas in the early parts of this year has been to extract some of my side projects, such as Serious Business and Charleston Weather, out from under so that I could give them some room to breathe and take on lives of their own. This process has largely been completed for Serious Business, as I was able to move it to a Tumblr site (which has worked well so far). Establishing Serious Business with its own branded site and Twitter account have been useful in forming a stable audience.

Now that Serious Business is done, it’s time to give my weather efforts the same treatment. The work on that started very, very early this morning, culminating in a somewhat buggy rough draft of the beginnings of a brand new Charleston Weather site at