Saturday, May 23, 2009

Five weather events worth chatting about

Visitors gather under the famous sign welcoming motorists on the south end of the Las Vegas Strip during a rare snowstorm December 17, 2008 in Las Vegas, Nevada. Several inches of snow were expected to accumulate in and around Las Vegas.

(The following is reprinted with permission from and

Usually, the weather is a subject for polite, uneventful conversation with people you don't know very well. But sometimes the weather is weird, or even downright scary. Here are a few examples of weather events that gave neighbors more than enough to awkwardly discuss.

1. Dramatic Changes

Midwesterners are accustomed to using both their heat and air conditioning in the same day due to dramatic temperature changes and unseasonable weather. The "Great Blue Norther" of 1911 was the most dramatic cold snap ever recorded—several cities set record high and low temperatures on the same day. On November 11, 1911 (yes, 11/11/11) a massive storm system separated warm air from arctic air, yielding violent wind and storms. Kansas City, Missouri reached a high temperature of 76° F (24 °C), and by midnight, the temperature plunged to 11° F (-11 C°). The 65 degree difference was replicated in Oklahoma City and Springfield, Missouri.

The complete article in is here.

Hubble's final servicing mission

(Bad weather over Cape Canaveral is delaying the landing of the Space Shuttle Atlantis - Florida has seen drought-busting, almost biblical rains this last week, some towns near Orlando have been inundated by 24" of water since last weekend). did a wonderful job providing background, beautiful images and solid explanations about this, the final repair mission for the Hubble Space Telescope, which seemed to go very well, from all the reports I've heard. Mr. Fix-It would be proud of the 7 astronauts and their efforts to tinker and tweak, while floating more than 230 miles above the planet. Pretty amazing when you stop and think about what they're doing!)

On Monday, May 11, after months of delays and preparation, NASA's Space Shuttle Atlantis launched from the Kennedy Space Center on the final servicing mission to the orbiting Hubble Space Telescope. The seven crew members left Florida for low Earth orbit at 2:01 pm, for a scheduled 11-day mission, including 5 days of Extra-vehicular activity (EVAs) to work on the Hubble. So far the repairs appear to be going very well - the final EVA is scheduled for today, and the landing planned for May 22nd. I was fortunate enough to attend the launch at Banana Creek viewing area, and wish to extend my gratitude to all the people at NASA.

Click here to check out photographer Alan Taylor's excellent (and visual) story in

Friday, May 22, 2009

3 Body Scatter Spike

(when you see a "finger" jutting out of a thunderstorm on Doppler radar, there's a good chance that particular cell is producing large, potentially damaging hail, ping-pong to softball size. This artifact, this electronic signature is produced when the radar beam interacts with large hailstones within a thunderstorm updraft, creating a surge of energy, a "spike" on the edge of the thunderstorm. The top image shows VIL Density, a measure of hail volume within the cell. The lower image is Storm Relativy Velocity, showing motion of raindrops and hail stones. Green returns are moving away from the radar site, the red returns are moving toward the site, indicating strong rotation within this severe "mesocyclone". These violent, spinning thunderheads are most likely to spawn large, damaging hail and on occasion: tornadoes.)

From Wikipedia:

A three body scatter spike or TBSS is an artifact on a weather radar display indicative of large hail. They are identified by a spike of weak reflectivity echos that extend out from a thunderstorm, and away from the radar site.


Also known as hail spikes, these are the result of energy from the radar hitting hail and being deflected to the ground, where they deflect back to the hail and then to the radar. Because of the energy hitting the ground at least once and the hail multiple times, it has a weaker return echo than the energy that went from the radar to the hail and back to the radar. The spike occurs where the energy took more time to go from the hail to the ground and back as opposed to the energy that went direct from the hail to the radar. This results in the radar picking up the energy at a later time which puts the echo further away from the radar than the actual location of the hail on the same radial path. Since hail cores are most intense at higher elevations, hail spikes only appear at the levels aloft that accompany the most intense hail. Because of this, hail spikes are usually not seen at lower elevations.

Use in forecasting

Because of their observed accuracy in indicating large hail aloft, TBSS's are used operationally by the National Weather Service to identify thunderstorms that could likely produce large, severe hail. This would warrant the issuance of a severe thunderstorm warning or mention of large hail in a tornado warning.

A cross-Section of a Three body spike from an Anti-Cyclonic Thunderstorm.

Climate change odds much worse than thought

ScienceDaily (May 20, 2009) — The most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth's climate will get in this century shows that without rapid and massive action, the problem will be about twice as severe as previously estimated six years ago - and could be even worse than that. The study uses the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined by the Joint Program on the Science and Policy of Global Change since the early 1990s. The new research involved 400 runs of the model with each run using slight variations in input parameters, selected so that each run has about an equal probability of being correct based on present observations and knowledge. Other research groups have estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself. But the MIT model is the only one that interactively includes detailed treatment of possible changes in human activities as well - such as the degree of economic growth, with its associated energy use, in different countries.

The complete article in Science Daily is here.

Wednesday, May 20, 2009

As Alaska glaciers melt, it's land that's rising

JUNEAU, Alaska — Global warming conjures images of rising seas that threaten coastal areas. But in Juneau, as almost nowhere else in the world, climate change is having the opposite effect: As the glaciers here melt, the land is rising, causing the sea to retreat. Morgan DeBoer, a property owner, opened a nine-hole golf course at the mouth of Glacier Bay in 1998, on land that was underwater when his family first settled here 50 years ago.“The highest tides of the year would come into what is now my driving range area,” Mr. DeBoer said.Now, with the high-tide line receding even farther, he is contemplating adding another nine holes. “It just keeps rising,” he said.

The complete text of the New York Times article is here.

Antarctic Voyage: climate change upfront

"Our square sails are braced right now for the changing wind that we expect ahead as we cross Drake Passage, between Cape Horn and Antarctica," says Mike Stewart, the boatswain of the Dutch tall ship Europa. Surging along the crests of 20-foot, slate-gray waves, the Europa is taking 15 crew members and 40 sail trainees to the Antarctic Peninsula.

The wind moans in the rigging, setting every brass hook and teak panel clanking, rattling, shivering, and heaving. Regularly thrown off balance, the men and women on board are willing to put up with discomfort to see the effects of climate change in Antarctica firsthand.

The impending collapse of the 5,600-square-mile Wilkins Ice Shelf adds a sense of urgency to the voyage. The Antarctic Peninsula, which stretches 750 miles north from the continent into Drake Passage, is arguably undergoing the fastest rate of climate change of any region on earth.

For the complete article from ABC's web site click here.

Sunday, May 17, 2009

First tropical storm of the season?

Image courtesy of Ham Weather, based in Atlanta. This is a tremendous source of graphics, weather loops and severe storm information. A considerable amount of weather data is free, but true weather enthusiasts may want to consider a data plan. For a very modest monthly fee you can gain access to unlimited global data, and tap thousands of maps for your own web site. It's one of the best weather sites on the web. Click here for a link to Ham Weather.


Computer models are consistently hinting at a significant tropical depression brewing near Cuba strengthening in the Gulf of Mexico, soaking much of Florida with torrential rains. There's at least a 1 in 3 chance the storm will intensify over the warm waters of the Gulf of Mexico (although there's considerable wind shear, which is less than ideal for rapid development). That said, we may be looking at Tropical Storm Ana forming by midweek.

Here is some interesting information about the naming of hurricanes, including the official list of hurricane names for 2009. (Courtesy: NOAA)

For every year, there is a pre-approved list of names for tropical storms and hurricanes. These lists have been generated by the National Hurricane Center since 1953. At first, the lists consisted of only female names; however, since 1979, the lists alternate between male and female.

Hurricanes are named alphabetically from the list in chronological order. Thus the first tropical storm or hurricane of the year has a name that begins with "A" and the second is given the name that begins with "B." The lists contain names that begin from A to W, but exclude names that begin with a "Q" or "U."

There are six lists that continue to rotate. The lists only change when there is a hurricane that is so devastating, the name is retired and another name replaces it.

2009 Hurricane Names