Archive for July, 2009

Severe Storm Threat Friday
July 31, 2009


The Thursday evening weather map indicates a threat of severe thunderstorms is developing for Friday afternoon.  Four key ingredients are in place and approaching from the west.  1.) The warm, muggy air we’ve been dealing with the last few days will remain in place as a steady south wind taps into tropical moisture near the Gulf of Mexico.  2.)  A cold front is pushing east through the great lakes and Ohio valley and is forecast to cross the mountains and slide into the warm, muggy air on Friday.  3.)  Low pressure has developed on the front over western Tennessee and will ride northeast along the front into the mid Atlantic region on Friday.  4.)  A relatively strong late July jet stream is ripping from southwest to northeast over the midwest into the great lakes with winds of 125 knots (143 mph) measured at 30,000 feet over Michigan.  If these ingredients hold together as they translate eastward early Friday, severe thunderstorms may develop in our area.  The National Weather Service’s Storm Prediction Center has us in the “slight risk of severe” area as of late Thursday evening.  Stay tuned to WBAL TV-11 and right here at for updates throughout the day.

Tom Tasselmyer


When Thunder Roars
July 29, 2009


Howard County has initiated a new weather safety program called “When Thunder Roars, Go Indoors”.


The program is intended to reinforce a very simple concept concerning lightening safety. If you can hear thunder, dangerous lightening is nearby and you should seek shelter.

The program involves the simplest of technologies, your ears and your brain. If you hear thunder you could become a lightening statistic. An average of nearly 60 people are killed each year and 300 injured by lightening.

Howard County will be placing signs at county parks, schools and other public places as a reminder that the sound of thunder is the warning to seek shelter. This initiative is the first of its’ kind in the nation.

Rob Roblin will have a story on this during the Wednesday evening newscasts. Be watching.

Rob  Roblin produced a story on the Howard County effort and you can view it on the video section of Click on this link…… and then click “Local” to find the story.

Below is a quick overview on lightening safety from NOAA.

LighteningjJohn Collins

First Picture
July 28, 2009

NOAA’s newest weather satellite produced it’s first image yesterday.


After testing, GOES-14 will be placed in a storage orbit until it is called on to replace one of NOAA’s older weather satellites. That would tentatively be sometime in early 2012.

John Collins

Planetary Collision
July 25, 2009

Something hit the planet Jupiter on July 19 and a large disturbance in the clouds surrounding the planet has been left behind as a marker.

NASA focused the Hubble Telescope on the huge planet and has released the photos below.

372847main_p0923ay_516This Hubble picture, taken on July 23, by the new Wide Field Camera 3, is the sharpest visible-light picture taken of the atmospheric debris from a comet or asteroid that collided with Jupiter on July 19. This is Hubble’s first science observation following its repair and upgrade in May. The size of the impactor is estimated to be as large as several football fields.
Image Credit: NASA, ESA, and H. Hammel (Space Science Institute, Boulder, Colo.), and the Jupiter Impact Team

The full NASA press release on the Hubble photo is below.


NASA’s Hubble Space Telescope has taken the sharpest visible-light picture yet of atmospheric debris from an object that collided with Jupiter on July 19. NASA scientists decided to interrupt the recently refurbished observatory’s checkout and calibration to take the image of a new, expanding spot on the giant planet on July 23.

Discovered by Australian amateur astronomer Anthony Wesley, the spot was created when a small comet or asteroid plunged into Jupiter’s atmosphere and disintegrated. The only other time such a feature has been seen on Jupiter was 15 years ago after the collision of fragments from comet Shoemaker-Levy 9.

“Because we believe this magnitude of impact is rare, we are very fortunate to see it with Hubble,” said Amy Simon-Miller of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Details seen in the Hubble view shows a lumpiness to the debris plume caused by turbulence in Jupiter’s atmosphere.”

The new Hubble images also confirm that a May servicing visit by space shuttle astronauts was a big success.

“This image of the impact on Jupiter is fantastic,” said U.S. Sen. Barbara A. Mikulski, D-Md., chairwoman of the Commerce, Justice and Science Appropriations Subcommittee. “It tells us that our astronauts and the ground crew at the Goddard Space Flight Center successfully repaired the Hubble telescope. I’m so proud of them and I can’t wait to see what’s next from Hubble.”

For the past several days, Earth-based telescopes have been trained on Jupiter. To capture the unfolding drama 360 million miles away, Matt Mountain, director of the Space Telescope Science Institute in Baltimore, gave observation time to a team of astronomers led by Heidi Hammel of the Space Science Institute in Boulder, Colo.

“Hubble’s truly exquisite imaging capability has revealed an astonishing wealth of detail in the impact site,” Hammel said. “By combining these images with our ground-based data at other wavelengths, our Hubble data will allow a comprehensive understanding of exactly what is happening to the impact debris.”

Simon-Miller estimated the diameter of the impacting object was the size of several football fields. The force of the explosion on Jupiter was thousands of times more powerful than the suspected comet or asteroid that exploded over the Siberian Tunguska River Valley in June 1908.

The image was taken with the Wide Field Camera 3. The new camera, installed by the astronauts aboard space shuttle Atlantis in May, is not yet fully calibrated. While it is possible to obtain celestial images, the camera’s full power has yet to be seen.

“This is just one example of what Hubble’s new, state-of-the-art camera can do, thanks to the STS-125 astronauts and the entire Hubble team,” said Ed Weiler, associate administrator of NASA’s Science Mission Directorate in Washington. “However, the best is yet to come.”


While on the subject of space, a story earlier this week was a bit more down to earth. A rare total solar eclipse was visible over parts of Asia and the western Pacific.  In an earlier post I displayed a weather satellite picture of the shadow cast on earth by the eclipse. A NASA solar observation satellite captured the event. The story and pictures are below.

John Collins

The Hinode satellite observing our sun captured images of the moon traversing the face of the sun during a solar eclipse this week.

On Wednesday, July 22, 2009, a total eclipse of the Sun was visible from within a narrow corridor that traverses half of Earth. The path of the Moon’s umbral shadow began in India and crossed through Nepal, Bangladesh, Bhutan, Myanmar and China. After leaving mainland Asia, the path crossed Japan’s Ryukyu Islands and curved southeast through the Pacific Ocean where the maximum duration of totality reached 6 minutes and 39 seconds. A partial eclipse is seen within the much broader path of the Moon’s penumbral shadow, which includes most of eastern Asia, Indonesia, and the Pacific Ocean. (NASA/JAXA)

Images of Solar Eclipse as seen by Hinode Satellite 07.23.09

372618main_XRTEclCol0041_1024x1024Hinode Satellite X-Ray Image of the Solar Eclipse

372614main_diamondring09_3994_3872x2592NASA image of the “diamond ring” phase of the eclipse. The sun is nearly covered by the moon and the last bit of light is visible through valleys on the moon’s surface.

372609main_corona09_4047_3872x2592NASA image of the eclipse at “totality”, showing the corona surrounding the sun.

Solar Eclipse Shadow
July 23, 2009

Wednesday’s total solar eclipse over Asia was a spectacular event. The area of “totality”, where the sun was completely covered by the moon, stretched from western Inda, across southern China and out into the Pacific Ocean.

The NOAA image below is from a totally different perspective than the pictures we’ve seen of the event.


The satellite image of coastal China shows the shadow cast on earth by the moon passing between the sun and earth.

This particular eclipse was unique in one respect. In some areas that experienced the full masking of the sun by the moon, the shadow of “totality” lasted a little longer than six and a half minutes. As eclipses go, this is unusually long.

The U.S. was left out of this event but there will be two lunar eclipses that will be visible from the east coast this year. On August 5 a penumbral eclipse will take place at moonrise and may be difficult to see. The moon will only be lightly shadowed in this case. On Decemper 31 a partial eclipse will take place over the northeast U.S.

John Collins

Rain Chances Higher
July 21, 2009

The July weather pattern has been dry and unseasonably cool.

At BWI-Marshall Airport the temperature has reached into the 90s only twice this month and up to Monday evening, less than a half inch of rain has fallen.

While the basic pattern this week remains unchanged, the odds for some rain have increased.


The Monday evening water vapor satellite imagery visualizes two opportunities for rain this week. A disturbance along the Eastern Seaboard will generate a few showers or thunderstorms in the region early in the week. At the end of the week, elements of the disturbance in the central U.S. will move in with a rain chance.

With rain in Baltimore about two inches short of the average so far this month, a little rain would be welcomed.

John Collins

Hottest since last year
July 17, 2009


We’ve only had two days with temperatures in the 90s this summer (3 back in April) and July is running 3.5° below normal, but at least for a day it felt like a typical hazy, hot, and humid summer day in Baltimore.  With temperatures reaching into the low and mid 90s across the region, Friday was the hottest day in almost exactly a year.  Clouds and a cool front will likely begin to drop temperatures back to normal and below for Friday and the weekend.

Tom Tasselmyer

Coolest July start in 15 years
July 11, 2009

On the 73rd anniversary of Maryland’s hottest day, the National Weather Service reported the first week and a half of July 2009 was the coolest in 15 years, running more than 4° below average for the first ten days of the month.

It was July 10, 1936 when the temperature in Baltimore soared to 107°, setting an all-time record high.  In western Maryland the temperature reached 109° at Frederick and Cumberland to establish the all-time record high for the state.

It was also on July 10th, but this time a couple decades earlier (1913) when the hottest temperature ever recorded in North America was set at Death Valley, CA:  134°!

In sharp contrast to those scorching temperatures in the first half of the 20th century, every day so far in this July of 2009 has featured temperatures at or below normal.  And, we have not had a 90° temperature at our official weather station at BWI-Marshall since April 27th.

Tom Tasselmyer



Record cold…frost in July!
July 9, 2009

Right in the middle of what is normally the hottest time of the year, it is record cold making the headlines in 2009.  On Prince Edward Island, Canada, temperatures dropped into the 30s early Wednesday morning, producing what many believe is the first ever July frost for that Canadian province.  The report from CBC News is posted below.  FYI, the temperatures in the article are in celcius: 3.8C = 39F, 5.1C = 41F, 22C = 72F.

Tom Tasselmyer

Frost in July hits P.E.I.

Last Updated: Wednesday, July 8, 2009 | 1:50 PM AT

CBC News

Temperatures dropped to a record low in Prince Edward Island overnight Tuesday, with reports of frost throughout the province.

An official record low of 3.8 C was set early Wednesday morning at Charlottetown airport.

The previous record for that date was 5.1 C, set in 2005.

Bob Robichaud, a meteorologist with Environment Canada, said that to his knowledge, frost has never been reported before in July in P.E.I.

“That 3.8 we got last night kind of sticks out as being lower than some of the other records for anytime in early July,” Robichaud told CBC News on Wednesday.

“So we’re looking at a significant event,” he said.

Environment Canada has issued a frost risk warning in low-lying areas of the province for Wednesday night. The temperature is expected to dip to 4 C.

The forecast for Thursday, however, calls for sunny skies and a temperature of 22 C for the province.

Triple Hs of summer on hold…so far…
July 6, 2009

The typical hazy, hot, humid days of summer have been put on hold by a cooler than normal weather pattern.  Low pressure in eastern Canada continues to funnel cooler and drier than normal air into the mid Atlantic and northeastern United States.  At BWI-Marshall, we have not hit 90° since an unusual three day heatwave in late April (April 25-27) and  temperatures for the first 6 days of July are running 4.2° below normal.

Tom Tasselmyer