Waterspout Over Galveston Bay, Texas, Likely Came Ashore As Tornado
Published: Jun 26, 2014, 6:05 PM EDT weather.com
The_Greyson21/TwitterA photo from The_Greyson21 on Twitter shows the waterspout over Galveston Bay, Texas.A waterspout that formed over Galveston Bay Thursday reportedly came on shore as a tornado near Texas City, Texas.According to Chron.com, a man in Freddiesville was pinned down by flying debris after the storm tossed his trailer into power lines. He wasn’t hurt.Roofs, trees and power lines were also damaged, according to Click2Houston.com.The National Weather Service typically sends a survey team to investigate reported tornadoes a day after the storm, which is likely to happen Friday.(MORE: Track Severe Storms)
Stu Ostro, Michael Lowry, Dr. Greg Postel Published: Jun 26, 2014, 4:16 PM EDT weather.com
Published: Jun 26, 2014, 11:16 AM EDT weather.com Actor Rob Lowe, star of television shows „The West Wing” and „Parks and Recreation,” and his family were rescued from their vacation home in the south of France on Wednesday after torrential rains flooded the first floor of their home.The New York Daily News reported that the 50-year-old Lowe, along with his wife Sheryl Berkoff and son John, had to be rescued after a massive storm struck where they were staying in Grasse, France, dropping three months’ worth of rainfall in four hours.Lowe snapped this photo of the floodwaters, which he posted on Instagram:
By Jon Erdman Published: Jun 26, 2014, 10:57 AM EDT weather.comTornado Hits Brunswick, OH There was no tornado warning issued when an EF1 tornado tore through a part of Brunswick, Ohio, on Monday evening, damaging at least 45 homes and businesses, according to a storm survey from the National Weather Service’s office in Cleveland. No injuries were reported.Above: Reports of severe weather (tornadoes: red tornado symbols, large hail: white circles, high winds/wind damage: blue arrows) from June 23, 2014.In this era of Doppler radar, enhanced spotter networks and social media, how did this happen? The short answer is this was a difficult case for any forecaster, even those with experience, to diagnose in real time. Let’s step through the event starting with the day’s forecast.The Forecast: Nothing Stood Out
Base reflectivity (left) and storm-relative velocity (right) from the NWS-Cleveland Doppler radar from 6:46 to 7:10 p.m. ET on Jun. 23, 2014. Rotation detected by radar denoted by red circles at right. (NWS, Gibson Ridge)These boundaries are a source of horizontal vorticity, or spin, in the lowest levels of the atmosphere, as rain, or in one case above, lake-cooled air rushes outward. Think of this similar to rolling a pencil on your desk.When boundaries collide, unstable air is lifted, and either new thunderstorms are formed, or existing storms are given a boost by the uplift.In this case, as you can see in the zoomed-up radar animation above at left, a cluster of thunderstorms was given such a boost after the aforementioned boundaries collided. This prompted the National Weather Service office in Cleveland to issue a severe thunderstorm warning at 6:54 p.m.ET.
Text of NWS-Cleveland severe thunderstorm warning issued at 6:54 p.m. ET on June 23, 2014. (NWS Cleveland)At that time, there was a signature in Doppler radar suggesting strong, straight-line wind gusts were possible, as shown by the brighter green shadings in the middle radar images above at right.Less than two minutes later, a tighter rotation began to appear in new storm-relative velocity imagery, denoted by the red circle above at right. This was, in fact, the Brunswick tornado.What changed so quickly to spawn this tornado?We mentioned the boundaries as a source of horizontal spin earlier. When a thunderstorm’s updraft passes over these boundaries, their horizontal spin can be tilted and stretched by the thunderstorm’s updraft into the vertical. This may have been how the Brunswick tornado formed.Interestingly, merging thunderstorm cells (illustrated in the first radar loop above) may have also played a factor in the Brunswick case, as recent research on the Moore, Oklahoma, 2013 tornado illustrates.However, just as fast as the rotation appeared, it weakened as the outflow boundaries continued surging past the storm cluster they boosted, cutting off the flow of warm, humid air thunderstorms feed off of.The final storm survey from NWS Cleveland estimated the tornado lasted only five minutes, from 6:55 to 7:00 p.m.Lessons Learned?So, from a forecast perspective, let’s recap:
- Tornado threat Monday was generally low, but not zero.
- A severe thunderstorm warning was issued for strong straight-line (non-tornadic) winds.
- Less than two minutes later, rotation tightened, but lasted no longer than five minutes total.
Suffice it to say, this was an exceedingly difficult short-lived scenario to react to quickly, even for experienced forecasters.The conventional radar reflectivity signature was not in any way suggestive of a tornado, compared to a more classic hook echo in a tornadic supercell.A 2013 study of two years’ worth of National Weather Service tornado warnings found the probability of detection (defined as an event for which a tornado occurred inside a tornado-warned area/time) for non-supercell tornadoes, such as Brunswick, Ohio, was only 46 percent, meaning roughly every other non-supercell tornado is not covered by a tornado warning when it forms.These non-supercell cases are simply more difficult for a forecaster to detect.As unsettling as that sounds, for supercell tornadoes, the probability of detection was found to be 85 percent. Generally speaking, the most destructive, violent tornadoes tend to occur on days where the large-scale setup tends to favor tornadic supercells, and are the easiest to detect on radar.Simply put, due to various factors – gaps in radar coverage, geometry of the radar beam rising away from the surface with distance, nighttime tornadoes, a lack of spotters at any given time – a tornado cannot be detected every time.(MORE: The Tornado East Texas Never Saw Coming)This puts NWS forecasters in a catch-22:
- Issue more tornado warnings to attempt to capture every tornado, but then risk more false alarms, increasing complacency in response by the public.
- Issue fewer warnings, focusing on stronger tornadoes more likely to claim lives, but then risk missing more EF0, EF1 tornadoes. With fewer weak tornadoes warned, there’s no guarantee more fatalities wouldn’t result.
For now, the answer is close to the first option, as missing tornadoes is less acceptable and palatable than false alarms.(MORE: Tornado Warning False Alarms)It is always good practice to seek shelter for severe thunderstorm warnings. As National Weather Service severe thunderstorm warnings often say, severe thunderstorms can produce tornadoes with little or no advance warning.MORE ON WEATHER.COM: Could This Save You From a Tornado?Play VideoCould This Save You From a Tornado?
Midwest Flooding Crisis Likely to Worsen as Storms Return to Minnesota, Iowa, Wisconsin, South Dakota, Nebraska
By Sean Breslin Published: Jun 26, 2014, 8:48 AM EDT weather.com