Weather Wednesday – May through July Outlook

The Climate Prediction Center recently issued its 90-day outlook for temperature and precipitation for the U.S. It also updated the drought monitor tool.

off01_tempIn general the outlook calls for the next three months to feature above normal temperatures in the western third of the country and in the far southeastern states. Alaska and the Pacific Northwest will also be warmer than usual. Below normal temperatures are confined to much of Texas and areas of adjoining states. Most of the country will see an equal chance for above or below normal temperatures.

 

off01_prcpMuch of the nation may experience above normal precipitation from the southeast through the gulf states to the western plains and Rockies along with a good portion of Alaska. The above normal rainfall may bring drought relief to Texas and the four corners area. The Great Lakes states will see below normal precipitation and the potential of a developing drought. Lake levels and fire danger may be impacted.

 

drought 90The drought monitor shows little change in the near term for the hardest hit areas of the west, parts of Texas, and parts of the Dakotas, Minnesota and Wisconsin. Over the 90 day period of the outlook, the drought may ease in Texas and areas northwest of there. However, drought conditions may expand in the Great Lakes. Unfortunately, little or no relief is seen for California.  Just this week water use restrictions of from 8% to 36% were enacted for some municipalities.

Late breaking news.  Tornadoes in Germany!

There was a fairly broad outbreak of severe weather including tornadoes in Germany on Tuesday, May 5.  Here’s coverage from the British newspaper, The Guardian.

Weather Wednesday – First Tornado Captured by Radar

62 years ago this month, April 9, 1953, about 3 miles from where I am sitting, a tornado was caught by radar for the first time. Scientists and electrical engineers at the Illinois State Water Survey at the University of Illinois at Urbana-Champaign had modified a former WWII airborne radar for use in estimating amounts of precipitation falling from storms.

Don Staggs, an electrical engineer, was preparing the radar for later field tests. He started to notice what we now call “hook echo” returns in the scans of the storm. As afternoon turned to evening, a strong thunderstorm developed just north of Champaign, about ten miles from the radar site at the university-owned Willard Airport. The storm image included a pronounced hook on the bottom rear flank much as we see hook echoes on modern Doppler radar.

first radar image of a tornado
Illinois State Water Survey via The News Gazette

Still photos and a 16mm film of the images on the scope captured that moment. A team of meteorologists and technicians were able to study the image capture. Later, Dr. Ted Fujita the creator of the tornado strength measurement scale that bears his name, sketched over 200 of the frames of the film in his own hand. All of this can be seen in a terrific article from Colorado State University.  Note especially the photos of the tornado and the well-developed wall cloud.

We now know that the radar captured the early stages of an F3 tornado that eventually traveled about 160 miles and dissipated near Albany, IN. There were two fatalities and about $4-million in property damage in Illinois. The path of the storm took it across mostly rural areas.

Next week, we’ll discuss current use of radar and what may be the next generation of this important forecast tool.

Weather Wednesday — April 9, 2015 Illinois Tornado Outbreak

On this Tax Day edition of Weather Wednesday, we’ll revisit last week’s tornado outbreak in Illinois. Statewide, 11 tornadoes have been confirmed in the April 9th event. The earliest, which caused very little damage, was reported just northwest of Peoria in the afternoon hours. By early evening, strong thunderstorms were crossing far northern Illinois and eventually spawned the first EF-4 tornadoes ever reported in DeKalb and Ogle Counties (records kept since 1950) and the strongest tornado in the National Weather Service Chicago Office County Warning Area since an EF-5 devastated Plainfield, in the southwest suburbs, in 1990.

AP_fairdale_tornado_14_sk_150410_16x9_1600
AP

Two people were killed in the unincorporated town of Fairdale where nearly every structure, more than 70 in all counting outbuildings, was either damaged or destroyed. 22 injuries were reported in the outbreak. The tornadoes eventually approached the far western suburbs of Chicago but missed three population centers near their path. Damage was widely scattered in a multi-county area.

PBrooksPhotography_Ashton
PBrooks Photography

This outbreak was well forecast and there is general agreement there was plenty of warning. The Storm Prediction Center (SPC), as it did with the EF-3 and 4 tornadoes in Illinois on November 17, 2013, mentioned possibly tornadic storms at least four days in advance.

The National Weather Service Chicago Office updated their summary of the tornadoes just this morning. This is one of the most complete such documents I’ve ever read and includes some of the few satellite images of a tornado’s path I’ve ever seen. Read it all the way to the bottom and you’ll see the SPC guidance in the week leading up to the storms.

LarissaSebree_HillcrestIL
Wedge tornado and wall cloud near Hillcrest, Illinois. Larissa Sebree via NOAA.

A couple of these tornadoes were extremely well documented via video (note:  Strong language toward end) and live streaming and some of the visuals of the rotating wall clouds were just about textbook. The low sun angle contributed how well the tornadoes were captured.

There was also a significant side issue involving a motorist by the name of Sam Smith who was shooting video. That footage was widely shown on television and the driver was taken to task for getting too close to the storm, even if accidentally.  (There are now licensing issues with the video so we won’t link to it here.  However, it is widely available on You Tube.)

There were a couple of takeaways from his experience which are good reminders to all of us who may encounter storms. First, if a funnel cloud or tornado does not appear to be moving, it is either headed straight for the observer or dead away from the observer. To be safe, get out of that area immediately by driving at right angles to the storm. Second, this motorist backed up to take shelter in his vehicle under a bridge. Although many people have done that and survived, experts say that is a bad idea because wind speed may actually be amplified as it is compressed into that confined space.  There have been fatalities of people under overpasses.