Forecasting 'Weather Bombs'
Navy Research Lab, Monterey
The explosive winter storm Jolle on January 26. Shortly before this image was captured Jolle reached a central pressure of 930 millibars, on par with a Category 4 hurricane.
May 15, 2012, Ormond Beach, Florida. Photo by
Oct. 2, 2012 --
NASA's Global Precipitation Measurement satellite mission is working to understanding extreme weather with photos of rain and snow worldwide every three hours. But how do these storms look on the ground? NASA's GPM extreme weather photo contest highlights the beauty and ferocity seen first hand from storm-chasers before they duck for cover. Here are NASA's top five picks from over 100 submissions. This photo by Jason Weingart, a photography student at the University of Central Florida, shows a Volusia County lifeguard signaling to surfers at Ormond Beach, Fla., that it is time to exit the water. "The storm actually pushed back on shore as it moved south, and then became strong enough for tornado warnings on three separate occasions. I saw a large wall cloud, another spectacular shelf cloud, and some very tight rotation in the couple hours I stuck with the storm after I left the beach in Ormond," wrote Weingart. NASA Fun Fact: "A shelf cloud is a type of arcus cloud with a wedge shape. It is a low level, horizontal cloud formation usually associated with the leading edge of thunderstorms. The leading (outer) part of the shelf cloud appears smooth due to rising cloud motions, while the underside often appears jagged and wind-torn."
May 22, 2011 Dane County, Wisconsin. Photo by
Atmospheric scientist Grant Petty of the University of Wisconsin - Madison, was with a photography club on a farm in Dane County when he saw this thunderstorm building several miles to the east. "The storm cell dropped 1-3/4 inch hail near Sun Prairie. Fall streaks barely visible under the right side of the anvil may in fact be the falling hail,” he said.
PHOTOS: Sun Dogs, Halos, and Double Rainbows
July 5, 2011 Maricopa, Arizona. Photo by Megg
“This photo was taken in a wash that runs through my neighborhood in Maricopa, AZ. The wash runs north/south through the neighborhood and the haboob (type of intense dust storm) was rolling in from the east," reported photographer Meggan Wood. "I saw the wall of dust coming and quickly drove to the wash to get a good wide-open view of the height of the dust looming over the houses. I barely had time to get back to my car before it hit and I was engulfed! The darkness was surprising but it only lasted about 10-15 minutes before it thinned out enough to where I could drive back home, only about 2 minutes away. This was the giant haboob that made national news when it rolled through and entirely covered all of Phoenix and some surrounding cities. Maricopa is about a half-hour drive south of the Phoenix Sky Harbor airport."
PHOTOS: After the Dust Settles
September 1, 2012 Arlington, Virginia, lookin
Journalist Brian Allen with the Voice of America was at home in Arlington, Va., when this storm rolled over Washington. "The storm that blew through started off with an incredible amount of lightning and then dumped a significant amount of rain in a short amount of time -- on the other side of the river. DC got drenched and Arlington didn't see a drop,” he reported.
NEWS: Lightning Still Largely a Mystery
May 30, 2012 Kechi, Kansas. Photo by Brian Jo
Writer and photographer Brian Johnson is a also an avid storm-chaser for several Kansas radio stations. “As a large squall line moved through the area. The National Weather Service had warned about a large scale Derecho forming and moving through," he wrote. "This spawned a couple brief severe thunderstorms that dumped hail on rush hour traffic before the main line moved in. As the bigger storm moved into the Wichita area, reports were coming in of 70 mph winds and hail. There is an open farm field roughly two miles from my house that I shot lightning on the previous night. I sat there for about 20 minutes before this large squall line pushed through the clouds. I was hit with a pretty good gust front as it got closer, but as the winds increased, I decided to get to shelter. This photo was one of the last ones I took." Read more about Johnson's storm-chasing adventure here:
NEWS: Photos Catch Monster Storm's Approach: Big Pics
PHOTOS: Twilight: 15 Reasons to Watch
Meteorologists have hit on one possible way to detect one of the worst kinds of storms before they take shape. Explosive cyclones, so called "meteorological bombs," pop into existence in a day or two and can wreak havoc on land, as well as at sea. That makes them especially hard to forecast.
Hurricane Sandy was a monster, but not a bomb, since it was forecast with extraordinary accuracy a week ahead. A meteorological bomb, on the other hand, develops at a frightening pace, with the atmospheric pressure dropping a millibar or more per hour for at least 24 hours.
In late January, there was a historic meteorological bomb in the North Atlantic, with the pressure dropping a startling 58 millibars in 24 hours. That storm, named Jolle, generated the mammoth waves that enabled surfer Garrett McNamara to break the world record on a 111-foot giant off the coast of Portugal.
"In a more typical storm, you might see a pressure drop of one millibar per hour over less than that number of hours," said meteorologist Greg Carbin of the U.S. National Weather Service's Storm Prediction Center.
But when conditions conspire to deepen a low pressure area faster and longer, the result is a forecasting challenge and a danger to life and limb.
In the new study published in Geophysical Research Letters, two Australian researchers stepped back from the storms and looked at the large-scale energy budgets, called "Lorenz energetics," of the atmosphere from 1980 to 2011 (32 years). The study focused specifically on the parts of the world most prone to explosive cyclones: the Northwest Pacific, the North Atlantic, the Southwest Pacific and the South Atlantic.
They found a strong energy signature that was "virtually identical for all four geographical regions," wrote the paper's authors, Mitchell Black and Alexandre Pezza of the University of Melbourne.
Even more promising is the fact that the energy signature of these bombs can be seen 48 hours before the actual storm takes shape. That suggests the method might be applied to lengthen forecast times.
"This finding opens a new avenue of exploration of explosive storm behavior based on the large-scale environment," wrote Black and Pezza.
A new tool for forecasting the bombs would be welcome since, despite significant events like Sandy being handled very well by the weather models, sudden storms can sometimes slip through the cracks, Carbin explained.