Stories tagged storm

Apr
28
2011

A number of severe thunderstorms have swept through the SE US recently. Some storms generated tornadoes that were truly devastating. The news channels have many photos of the ground destruction. We can see the path of the storms in satellite images. Here is a link to one of those images.

A comparison of 250-meter resolution image from a NASA MODIS instrument at 0.65 µm and 0.87 µm visible channel images centered on Tuscaloosa, Alabama on 28 April 2011 showed signatures of a few of the larger and longer tornado damage paths from the historic tornado outbreak (SPC storm reports) that occurred on 27 April 2011. The yellow arrows point to some of the paths.

Here is a link to an animation between the two channelsMODIS Image of Tornado Paths on 28 April 2011: NASA Satellite image see tornado path
MODIS Image of Tornado Paths on 28 April 2011: NASA Satellite image see tornado pathCourtesy CIMSS UW-Madison

http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2011/04/110428_m...

Sep
03
2010

WHY?: Clouds are hard to model, so let's show them who's boss.
WHY?: Clouds are hard to model, so let's show them who's boss.Courtesy Paige Shoemaker

Next time you look at the clouds, shake your fist and yell at those jerks for making our lives difficult. You might look crazy, but somebody needs to tell those fools.

While it's relatively easy to model temperature changes over the last century thanks to detailed records, clouds are more tricky to understand because we don't have a similar history of cloud observations, and also because they are ornery. So in order to understand how clouds work, scientists are building a body of evidence to model cloud behavior and help show how clouds will impact our weather as well as our climate in the future. I believe they also plan to show those clouds who is the boss of them.

Hurricane help!
Like a child running loose in a toy store, hurricanes have always been difficult to predict because they can unexpectedly change direction. This confounds plans for evacuation, leading some people to leave areas that are never hit, leading others to stay put and potentially face nasty weather because they don't trust the meteorologist, and leading meteorologists to keep Advil in business. But since the 90s, our ability to predict where hurricanes will make landfall has become twice as accurate. This new prescience is due to the development and use of more accurate models of how clouds work, which is in turn due to better understanding of cloud dynamics and faster computers. How about that, punk clouds?

Intensity, however, remains elusive to model. (Shh, don't let them know we have a weakness!)

Go home, son: If wily Earl thought he could outsmart the meteorologists, then he's in for a schoolin'.
Go home, son: If wily Earl thought he could outsmart the meteorologists, then he's in for a schoolin'.Courtesy NASA

"While we pride ourselves that the track forecast is getting better and better, we remain humbled by the uncertainties of the science we don't yet understand," Schott said. "This is not an algebra question where there's only one right answer."

-Timothy Schott, tropical cyclone program leader for the National Weather Service in Silver Spring, Md.

Hurricane Earl
Despite being a "forecasting nightmare," Earl ended up hitting about where it was predicted to go. This means that the right people have been evacuated to avoid injury and fatality. That's right, stick your tail between your legs, Earl.

Connecting to climate
Short-term events such as hurricanes and other storms are difficult to predict, but climate change is a whole other world of uncertainty--again, thanks to those uncouth clouds. Climate scientists are developing new tools, such as satellite technologies that show how much light different cloud types reflect and models that demonstrate localized cloud processes. These approaches look specifically at certain groups of clouds and their patterns of change to add detail to older, larger models that look at climate over larger scales.

Booyah!: Climate computer nerds prevail.
Booyah!: Climate computer nerds prevail.Courtesy Nic McPhee

The problem with the older models is that they have a low resolution that doesn't accurately represent clouds because the clouds are smaller than they can show. Think of it like Google maps--at the beginning, you're looking at the entire planet, or a whole continent--this is similar to older, low-res climate models. The new models are like zooming in on a city--you can see bus stops, restaurants, and highways. But you have to zoom out to see how these small pieces relate to the larger surroundings. In a similar way, the new high-res models are helping to inform older models--this type of work is called multiscale modeling.

Researchers at the Center for Multiscale Modeling of Atmospheric Processes (CMMAP) are developing this exact type of model. You can read about their advances here. This work is important because it brings insight into questions about whether clouds will reflect or trap more sunlight, which can have a big impact on the rate of global warming. It also helps us understand whether geoengineering projects that alter clouds will really have the intended effect. Plus it's just one more way we can pwn clouds.

Jul
30
2010

A new record hail stone fell on 23 July 2010 near Vivian SD!

It is 8-inch in diameter hail stone and weighs 1.9375 pounds.

The old record heaviest U.S. hailstone was a 1.67-pound found near Coffeyville, KS on Sep. 3, 1970. The old record for the largest diameter hailstone was 7 inches found in Aurora, NE on June 22, 2003. This Aurora, NE hailstone still holds the U.S. record for circumference: 18.75 inches. The Vivian, SD hailstone circumference was only 18.5".

Here is a photo of the stone

Hail is precipitation in the form of large balls or lumps of ice. Hailstones begin as small ice particles that grow primarily by accretion. The production of large hail requires a strong updraft that is tilted and an abundant supply of supercooled water. Because strong updrafts are required to generate large hailstones, it is not surprising to observe that hail is not randomly distributed in a thunderstorm; instead it occurs in regions near the strong updraft. Supercell thunderstorms, in which the strongest updrafts are created with help from the mesocyclone, often produce the largest hail.
Eventually, though, the weight of the hailstone overcomes the strength of the updraft, and it falls to earth. The curtain of hailstones that falls below the cloud base is called the hailshaft. These regions are often said to appear green to observers on the ground, although recent research suggests that heavy rain as well as hail can create this optical phenomenon. As the storm moves, it generates a hailswath, a section of ground covered with hail.

Hailstorms can severely damage crops, automobiles, and roofs. Sometimes the swath can be so big you can see it on the ground from a satellite

Jun
28
2010

Tropical Storm Alex, which formed over the northwestern Caribbean Sea out of a westward-moving tropical wave on Friday and Saturday (June 26 and27), emerged overnight into the Bay of Campeche from the Yucatan Peninsula. Since emerging from that landmass as a tropical depression (signifying sustained winds weaker than 35 knots), it has strengthened back to Tropical Storm status. Current forecasts place it as a hurricane — possibly major — near the northern Mexico Gulf Coast later this week.

Aug
19
2009

A felled tree in Central Park
A felled tree in Central ParkCourtesy zoolien
I don’t live in New York, and have only been there a couple of times. But the last time I was there I was able to spend a few minutes in wonderful Central Park, so this article caught my eye.

According to officials at the Department of Parks and Recreation and the Central Park Conservancy (who manage the park), over 100 trees were toppled in what they called the most severe destruction the park has seen in at least 30 years.

Check out these flickr images of the damage. Do you live in New York and/or have you seen the damage? Tell us about it by commenting below!

The National Oceanic and Atmospheric Administration (NOAA) has issued its Atlantic hurricane season forecast. The prediction -- "near-normal" -- fits pretty well with the forecasts from AccuWeather, Colorado State University, WSI Corporation, and the Weather Research Center. What does "near-normal" mean? NOAA is predicting 9 to 14 named storms, with 4 to 7 hurricanes, and 1 to 3 major storms (category 3 or higher on the Saffir-Simpson scale of storm intensity).

But storm prediction is a tricky business. More rainfall over West Africa, warmer sea surface temperatures, and reduced wind shear could encourage more storms. An El Nino pattern in the Pacific or cooler ocean temperatures could discourage them. NOAA will issue another prediction in August, just before the usual peak in the hurricane season.

Apr
09
2008

Noted hurricane forecaster Dr. William Gray has offered up his 2008 Atlantic hurricane season predictions. (The season begins on June 1 and runs through November 30.)

Hurricane Katrina, 8/29/05: This image was taken by NOAA's Geostationary Operational Environmental Satellite (GOES).
Hurricane Katrina, 8/29/05: This image was taken by NOAA's Geostationary Operational Environmental Satellite (GOES).Courtesy NOAA

Gray's team, working out of Colorado State University, is predicting an above-normal season, with 15 named storms, 8 hurricanes, and 4 major hurricanes (category 3 storms or higher). Why? A La Nina pattern creates cool water conditions in the Pacific and warm sea surface temperatures in the eastern Atlantic. Warm sea surface temperatures are critical to the formation of hurricanes.

What's "above average"? An average hurricane season produces about 10 tropical storms and 6 hurricanes. In 2007, 14 tropical storms formed, and 6 of those strengthened into hurricanes. But 2005, of course, was a record-shattering year, with 28 storms, including Hurricanes Katrina and Rita.

Here's the Science Buzz feature on hurricanes.

Buzz thread on Hurricane Katrina, started on 8/29/2005.

Buzz thread on Hurricane Rita, started on 9/22/2005.

Buzz thread on the 2007 Atlantic hurricane season

Buzz thread on the 2006 Atlantic hurricane season

Do you know about the 1938 hurricane that crashed into New England?

Interesting weather websites

Share your natural disaster stories.

And, lastly, here are the hurricane names for 2008:

  • Arthur
  • Bertha
  • Cristobal
  • Dolly
  • Edouard
  • Fay
  • Gustav
  • Hanna
  • Ike
  • Josephine
  • Kyle
  • Laura
  • Marco
  • Nana
  • Omar
  • Paloma
  • Rene
  • Sally
  • Teddy
  • Vicky
  • and Wilfred

Today, two years since Hurricane Katrina roared into New Orleans, the New York Times is featuring an interactive with videos (tagged to locations) about life in the city since the storm. Definitely worth a look.

Apr
18
2007

Ever wanted to be a storm spotter? Now's your chance! The National Weather Service (NWS) relies on local SKYWARN storm spotters to confirm, from the ground, what meteorologists are seeing on radar. NWS storm spotters are not tornado chasers like the folks in the movie "Twister." Instead, they report wind gusts, hail size, rainfall, cloud formations, and the like to NWS and local emergency management agencies.

Tornado: This tornado, seen in its early stages of formation over Union City, Oklahoma (May 24, 1973), was the first one caught by the National Severe Storms Laboratory doppler radar and chase personnel. (Photo courtesy NOAA Photo Library, NOAA Central Library; OA
Tornado: This tornado, seen in its early stages of formation over Union City, Oklahoma (May 24, 1973), was the first one caught by the National Severe Storms Laboratory doppler radar and chase personnel. (Photo courtesy NOAA Photo Library, NOAA Central Library; OA

New radar equipment is still not sensitive enough to determine the existence of an actual tornado. It can only predict where severe weather is likely to occur. So the NWS needs trained volunteers to verify actual severe weather.

With peak storm season just around the corner (mid-June here in the Upper Midwest), free, 2.5-hour classes are being offered to train new SkyWarn volunteers.

SkyWarn class schedule, greater Minnesota
SkyWarn class schedule, Twin Cities Metro area

Here's how you get started...