Weather

Curiosity captures clouds on Mars

September 9th, 2014 at 9:30 pm by under Weather

From IFL Science:

September 8, 2014 | by Janet Fang

photo credit: Clouds that are probably composed of ice crystals and possibly supercooled water droplets were caught in images by NASA’s Opportunity rover / NASA/JPL/Texas A&M/Cornell

Having just celebrated its two-year anniversary on the Red Planet back in August, NASA’s Curiosity has rolled in another achievement: capturing images of Martian clouds.

Last week, @MarsCuriosity shared this photo (right) and tweeted: “Head for the hills! I’m driving towards these hills on Mars to do geology work & also search for clouds.”

During its first year, the rover fulfilled its goal of determining whether Mars had environmental conditions favorable for microbial life when it found sedimentary rocks containing clay, suggesting that a lakebed existed billions of years ago. Then, in its second year, Curiosity drove towards its long-term science destination on the lower slopes of Mount Sharp at the center of Gale Crater.

By turning its instruments skyward, the rover hopes to shed light on weather patterns that have helped shape the climate on Mars. “Clouds are part of the planet’s climate system,”Robert Haberle of NASA Ames tells Astrobiology Magazine. “Their behavior tells us about winds and temperatures.” Winds are the primary mechanism that shaped the planet’s surface for the past three to four billion years, he adds.

The wind-blown Martian clouds captured by Curiosity are probably composed of ice crystals and supercooled water droplets—yet another indication of ancient Martian life. “Some studies suggest that clouds in the past may have significantly warmed the planet through a greenhouse effect,” Haberle explains. “A warmer environment is more conducive to life.”

[Via Astrobio.net]

Correction: NASA’s Opportunity took the cloud image above in 2006. https://twitter.com/MarsCuriosity/status/509123819835895809


A one-in-a-million weather photo

September 9th, 2014 at 1:42 pm by under Weather

Weather photographer Brian Miner took one of the most beautiful photos we’ve seen in a long time last week. Details from Climate CentralIn it, the arc of the rainbow stretches across a verdant field behind a squall line in Kansas. Miner saw the rainbow after he had moved to the back of the lines of storms to avoid hail. He backed into a driveway for a barn, set up his camera, wrapping it in a rain poncho, and then sat under the hatch of his SUV, he told Climate Central. Serendipitously, at the moment Miner took the photo, lightning — which he said was everywhere in the area — shot out from the storm clouds, almost appearing to emanate from the rainbow itself. Truly awesome.

Weather photographer Brian Miner snapped this image in Kansas after a squall line blew through but while it was still producing lightning.
Click image to enlarge. Credit: Brian Miner


Lightning Tips & Safety

September 9th, 2014 at 1:08 am by under Weather

lion lightning

Lightning: What You Need to Know

  • NO PLACE outside is safe when thunderstorms are in the area!!
  • If you hear thunder, lightning is close enough to strike you.
  • When you hear thunder, immediately move to safe shelter: a substantial building with electricity or plumbing or an enclosed, metal-topped vehicle with windows up.
  • Stay in safe shelter at least 30 minutes after you hear the last sound of thunder.

Indoor Lightning Safety

  • Stay off corded phones, computers and other electrical equipment that put you in direct contact with electricity.
  • Avoid plumbing, including sinks, baths and faucets.
  • Stay away from windows and doors, and stay off porches.
  • Do not lie on concrete floors, and do not lean against concrete walls.

Last Resort Outdoor Risk Reduction Tips

If you are caught outside with no safe shelter anywhere nearby the following actions mayreduce your risk:

  • Immediately get off elevated areas such as hills, mountain ridges or peaks
  • Never lie flat on the ground
  • Never shelter under an isolated tree
  • Never use a cliff or rocky overhang for shelter
  • Immediately get out and away from ponds, lakes and other bodies of water
  • Stay away from objects that conduct electricity (barbed wire fences, power lines, windmills, etc.)

noaa_logo

 LIGHTNING MYTHS AND FACTS

LIGHTNING AND CARS

Do the rubber tires on your car protect you if you are OUTside the car and you’re leaning on it? NO! Like trees, houses, and people, anything outside is at risk of being struck by lightning when thunderstorms are in the area, including cars. The good news though is that the outer metal shell of hard-topped metal vehicles does provide protection to those inside a vehicle with the windows closed. Unfortunately though, the vehicle doesn’t always fare so well.

A typical cloud-to-ground, actually cloud-to-vehicle, lightning strike will either strike the antenna of the vehicle or along the roofline. The lightning will then pass through the vehicle’s outer metal shell, then through the tires to the ground.

Although every lightning strike is different, damage to the antenna, electrical system, rear windshield, and tires is common. The heat from a lightning strike is sufficient to partially melt the antenna of a vehicle and can cause what seems like a small explosion of sparks as tiny fragments of metal melt and burn. A portion of the discharge may find its way into the vehicle’s electrical system and may damage or destroy electronic components, potentially leaving the car inoperable. The lightning may also find its way into the small defrosting wires that are embedded in rear windows causing the windows to shatter. Finally, it’s very common for the lightning to destroy one or more tires as it passes through the steel belts to the ground. It’s also possible for the lightning to ignite a fire which could destroy the vehicle.

 

Myth: Lightning never strikes the same place twice.
Fact: Lightning often strikes the same place repeatedly, especially if it’s a tall, pointy, isolated object. The Empire State Building is hit nearly 100 times a year.

Myth: If it’s not raining or there aren’t clouds overhead, you’re safe from lightning.
Fact: Lightning often strikes more than three miles from the center of the thunderstorm, far outside the rain or thunderstorm cloud. “Bolts from the blue” can strike 10-15 miles from the thunderstorm.

Myth: Rubber tires on a car protect you from lightning by insulating you from the ground.
Fact: Most cars are safe from lightning, but it is the metal roof and metal sides that protect you, NOT the rubber tires. Remember, convertibles, motorcycles, bicycles, open-shelled outdoor recreational vehicles and cars with fiberglass shells offer no protection from lightning. When lightning strikes a vehicle, it goes through the metal frame into the ground. Don’t lean on doors during a thunderstorm.

Myth: A lightning victim is electrified. If you touch them, you’ll be electrocuted.
Fact: The human body does not store electricity. It is perfectly safe to touch a lightning victim to give them first aid. This is the most chilling of lightning Myths. Imagine if someone died because people were afraid to give CPR!

Myth: If outside in a thunderstorm, you should seek shelter under a tree to stay dry.
Fact: Being underneath a tree is the second leading cause of lightning casualties. Better to get wet than fried!

Myth: If you are in a house, you are 100% safe from lightning.
Fact: A house is a safe place to be during a thunderstorm as long as you avoid anything that conducts electricity. This means staying off corded phones, electrical appliances, wires, TV cables, computers, plumbing, metal doors and windows. Windows are hazardous for two reasons: wind generated during a thunderstorm can blow objects into the window, breaking it and causing glass to shatter and second, in older homes, in rare instances, lightning can come in cracks in the sides of windows.

Myth: If thunderstorms threaten while you are outside playing a game, it is okay to finish it before seeking shelter.
Fact: Many lightning casualties occur because people do not seek shelter soon enough. No game is worth death or life-long injuries. Seek proper shelter immediately if you hear thunder. Adults are responsible for the safety of children.

Myth: Structures with metal, or metal on the body (jewelry, cell phones,Mp3 players, watches, etc), attract lightning.
Fact: Height, pointy shape, and isolation are the dominant factors controlling where a lightning bolt will strike. The presence of metal makes absolutely no difference on where lightning strikes. Mountains are made of stone but get struck by lightning many times a year. When lightning threatens, take proper protective action immediately by seeking a safe shelter – don’t waste time removing metal. While metal does not attract lightning, it does conduct it so stay away from metal fences, railing, bleachers, etc.

Myth: If trapped outside and lightning is about to strike, I should lie flat on the ground.
Fact: Lying flat increases your chance of being affected by potentially deadly ground current. If you are caught outside in a thunderstorm, you keep moving toward a safe shelter.

 

8-26 Bolt from the blue - noaa

 

5 Ways People Are Struck By Lightning

1.  DIRECT STRIKE - A person struck directly by lightning becomes a part of the main lightning discharge channel. Most often, direct strikes occur to victims who are in open areas. Direct strikes are not as common as the other ways people are struck by lightning, but they are potentially the most deadly. In most direct strikes, a portion of the current moves along and just over the skin surface (called flashover) and a portion of the current moves through the body-usually through the cardiovascular and/or nervous systems. The heat produced when lightning moves over the skin can produce burns, but the current moving through the body is of greatest concern. While the ability to survive any lightning strike is related to immediate medical attention, the amount of current moving through the body is also a factor.

animation of direct lightning strike

 

 

 

 

 

 

 

 

 

2.  SIDE FLASH -   -A side flash (also called a side splash) occurs when lightning strikes a taller object near the victim and a portion of the current jumps from taller object to the victim. In essence, the person acts as a “short circuit” for some of energy in the lightning discharge. Side flashes generally occur when the victim is within a foot or two of the object that is struck. Most often, side flash victims have taken shelter under a tree to avoid rain or hail.

animation of side lightning strike

 

 

 

 

 

 

 

 

3.  GROUND CURRENT –  When lightning strikes a tree or other object, much of the energy travels outward from the strike in and along the ground surface. This is known as the ground current. Anyone outside near a lightning strike is potentially a victim of ground current. In addition, ground current can travels in garage floors with conductive materials. Because the ground current affects a much larger area than the other causes of lightning casualties, the ground current causes the most lightning deaths and injuries. animation 2 of ground current direct lightning strikeGround current also kills many farm animals. Typically, the lightning enters the body at the contact point closest to the lightning strike, travels through the cardiovascular and/or nervous systems, and exits the body at the contact point farthest from the lightning. The greater the distance between contact points, the greater the potential for death or serious injury. Because large farm animals have a relatively large body-span, ground current from a nearby lightning strike is often fatal to livestock.

 

 

 

 

4.  CONDUCTION – Lightning can travel long distances in wires or other metal surfaces. Metal does not attract lightning, but it provides a path for the lightning to follow. Most indoor lightning casualties and some outdoor casualties are due to conduction. Whether inside or outside, anyone in contact with anything connected to metal wires, plumbing, or metal surfaces that extend outside is at risk. This includes anything that plugs into an electrical outlet, water faucets and showers, corded phones, and windows and doors.

animation of conduction lightning strike

 

 

 

 

 

 

 

 

 

 

5.  STREAMERS - While not as common as the other types of lightning injuries, people caught in “streamers” are at risk of being killed or injured by lightning. Streamers develop as the downward-moving leader approaches the ground. Typically, only one of the streamers makes contact with the leader as it approaches the ground and provides the path for the bright return stroke; however, when the main channel discharges, so do all the other streamers in the area. If a person is part of one of these streamers, they could be killed or injured during the streamer discharge even though the lightning channel was not completed between the cloud and the upward streamer. See Robert’s story as an example of a streamer injury.

animation of streamers lightning strike


Better weather forecasts mean fewer airline delays, less turbulence

September 8th, 2014 at 7:40 pm by under Weather

NY Times:

Amanda Terborg, an Aviation Weather Center meteorologist in Kansas City, Mo. CreditDan Gill for The New York Times

Just a few years ago, airlines got their weather reports by telex. Pilots pored over reams of paper and compared the forecasts with their flight plans. Once airborne, they depended on radio communications and rudimentary radar to avoid bad weather.

Now, pilots download detailed flight plans and weather reports full of intricate graphics onto tablet devices. Flight dispatchers track aircraft in real time and provide up-to-the minute weather data. New generations of airplane radar systems allow for easy in-flight adjustments.

The result? Fewer of the bumps, jolts and spilled drinks that have been a part of flying ever since the Wright Brothers.

“The secret sauce is how you use the information,” said Tim Campbell, senior vice president for air operations at American Airlines. “Fundamentally, it’s only a forecast and it’s still weather.

Stronger computing power, improved satellite and radar technology and more sophisticated scientific models have all given airlines a more detailed understanding of flying conditions. This means they can better plan their operations before flights — for instance by canceling flights early and avoiding stranding passengers at airports. During flights, they can better navigate around storms and avoid turbulence.

The Aviation Weather Center. CreditDan Gill for The New York Times

Weather accounted for 36 percent of all airline delays in 2013, down from 50 percent in 2003, according to the Bureau of Transportation Statistics.

(more…)


Beneficial overnight rain soaks much of the area

September 7th, 2014 at 9:07 am by under Weather

A slow-moving cold front combined with tropical moisture from Hurricane Norbert over Central Texas to produce wetting rain late Saturday through early Sunday morning.

Check out some of the luckiest–and most unlucky–communities in terms of rainfall totals below, or browse the list yourself here. Rain totals are as of 9 AM Sunday.

9-7 hill co rain

 

9-7 metro rain

 

9-7 east rain


Localized flash flooding possible tonight

September 6th, 2014 at 7:23 pm by under Weather

9-6 omni

 

As a slow-moving cold front interacts with deep, tropical moisture overnight tonight — the stage could be set for localized heavy rainfall and flash flooding.

Our exclusive in-house high-resolution model, pictured above, is forecasting the possibility of several hours of heavy, slow-moving thunderstorms in parts of Central Texas (including Metro Austin) from around 12:30am until 4am Sunday morning.

If this situation does play out, we could face problems with overnight flash flooding.

Find more details on your First Warning Forecast here, and in the below discussions courtesy of the NOAA Hydrometeorological Prediction Center and the National Weather Service:

NWS:

LATER TONIGHT...A COLD FRONT OVER NORTH TEXAS IS EXPECTED TO
MOVE INTO THE HILL COUNTRY AND BRING AN ADDITIONAL FOCUS FOR RAIN
LATE THIS EVENING INTO THE OVERNIGHT HOURS. THE COLD FRONT...AS
WELL AS ASSOCIATED OUTFLOW BOUNDARIES FROM CONVECTION...IS EXPECTED
TO PRODUCE HEAVY RAIN AND POSSIBLE LOCALIZED FLOODING. THESE AREAS
ARE GENERALLY NORTH OF A LINE FROM DEL RIO TO SEGUIN TO LEXINGTON.
THE REASONING OF POSSIBLE LOCALIZED FLOODING IS DUE TO SLOW MOVING
STORM MOTION/STEERING FLOW WHICH COULD RESULT IN RAINFALL AMOUNTS
OF 1 TO 3 INCHES WITH UP TO 5 INCHES POSSIBLE. THE TIMING IS FROM
ABOUT 7 PM TO 4 AM SUNDAY MORNING. BY SUNDAY MORNING...THE COLD
FRONT SHOULD BE EXITING OUR SOUTHERN COUNTIES WITH ISOLATED
SHOWERS AND THUNDERSTORMS LINGERING IN THE WAKE OF THE FRONT
MAINLY ALONG INTERSTATE 35 AND EASTERN COUNTIES.

NOAA HPC (technical):

...CENTRAL TEXAS...

THE BULK OF THE PCPN CURRENTLY ACROSS THE SRN PLAINS IS
ANAFRONTAL...HOWEVER...PER THE MOST RECENT STLT/RADAR TRENDS AHEAD
OF THE SFC COLD FRONT...SUPPORTED BY THE LATEST MESOSCALE
GUIDANCE...EXPECT A SWATH OF SLOW-MOVING CONVECTION TO ORGANIZE
ALONG AND AHEAD OF THE COLD FRONT ACROSS CENTRAL TEXAS WHERE THE
THERMODYNAMIC PROFILE IS MUCH MORE SUPPORTIVE OF A HEAVY RAINFALL
THREAT. THIS AS PRECIPITABLE WATER VALUES POOL NEAR 2.00 INCHES
ALONG THE FRONT...COUPLED WITH THE AVAILABLE DEEP-LAYER INSTBY
WITH MUCAPES BETWEEN 1500-2500 J/KG. WEAK OVERALL FLOW...INCLUDING
THE LLVL INFLOW...WITH 0-6 KM BULK SHEAR VALUES GENERALLY 15 KTS
OR LESS WILL LIMIT THE ORGANIZATION/DURATION OF DEVELOPING
CONVECTION...HOWEVER AS PER THE HIGH RES GUIDANCE HOURLY/3- HOURLY
RAINFALL RATES OF 2.5/3-5 INCHES RESPECTIVELY COULD CERTAINLY
TRIGGER ISOLATED RUNOFF ISSUES DESPITE THE CURRENT HIGH FLASH
FLOOD GUIDANCE.

Western drought drops Lake Mead to lowest level since it was built

September 5th, 2014 at 1:30 pm by under Weather

On July 11, the day these photos were taken, the Lake Mead reservoir reached its lowest water level since the lake was first filled during the construction of the Hoover Dam in the 1930s, according to the Bureau of Reclamation. The lake’s elevation was 1,081.77 feet—147.23 feet below capacity and 133.99 feet below its last peak in 1998. Similar to how the rings in the cross-section of a tree trunk can tell a story about that tree’s past, the high points and low points of Lake Mead’s water history can be glimpsed from observing recent photos taken at the Hoover Dam.

The highest rust-colored ring on the concrete dam structure shown in the top photo marks the height of the water when the lake is near capacity (it’s never allowed to literally fill to the tip-top).  The top of the dark ring around the water intake towers at image left in the foreground indicates the height of the water level on December 21, 2012—the highest the lake has been this decade. At the time, water levels were down 95.4 feet from 1998 levels. The white “bathtub ring” seen on the rocky sides of the reservoir in the bottom photo shows the historical high water level in the reservoir. The ring is a coating of minerals, deposited on the rocks while they were covered by water.

The Lake Mead reservoir—the largest in the United States—stores Colorado River water for delivery to farms, homes, and businesses in southern Nevada, Arizona, southern California, and northern Mexico. According to the National Park Service website, about 96 percent of the water in Lake Mead is from melted snow that fell in Colorado, Utah, New Mexico, and Wyoming. Each year, these “Upper Basin” states are required to allow a minimum flow of Colorado River water to reach Lake Mead.

This year’s new low was hardly unexpected. Runoff in the Upper Colorado River Basin was 94 percent of average in 2014, but that flow wasn’t enough to make up for the previous two years’ shortfalls: runoff was only 47 percent of normal in 2013 and 45 percent in 2012, according to the Bureau of Reclamation.

The past two years are a continuation of a15-year dry spell in the U.S. Southwest that has led to more water going out of Lake Mead than coming in. The lake reached an all-time high of 1,215.76 feet in November 1998, but it has not approached that level since. The Bureau’s Boulder Canyon Operations Office projects the lake’s elevation to continue to drop through the fall, falling to approximately 1,080 feet in November of this year.

Fluctuations in regional climate and the resulting water level in Lake Mead are an expected part of its operation, but many scientists are concerned that the recent prolonged drought could be a sign that the region will confront significant water supply challenges as greenhouse gas concentrations continue to rise.

Projections of precipitation changes in the Colorado watershed are less certain than those for temperature changes in the Southwest, but rising temperature along with declining snowpack and streamflows may threaten the reliability of surface water supply across the Southwest, according to the 2014 National Climate Assessment.

The report also warns that the current drought could be just beginning. Southwest paleoclimate records show that severe mega-droughts at least 50 years long have occurred in the past several thousand years. Unlike those ancient droughts, however, similarly dry periods in the future are projected to be substantially hotter, and for major river basins such as the Colorado River Basin, drought is projected to become more frequent, intense, and longer lasting than in the historical record.


Drought severe to exceptional across much of Central Texas

September 4th, 2014 at 3:55 pm by under Weather
Drought Monitor
DROUGHT INFORMATION STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1245 PM CDT THU SEP 4 2014

...DROUGHT CONDITIONS REMAIN THE SAME OVER THE PAST WEEK...
SYNOPSIS...
AFTER AN AUGUST THAT FEATURED SPORADIC RAINFALL...SEPTEMBER HAS SEEN
SPOTTY RAINFALL WITH THE MAJORITY OF RAIN FALLING ACROSS THE
SOUTHERN AND SOUTHEASTERN PORTIONS OF THE REGION. MOST
RIVERS...CREEKS AND STREAMS CONTINUED TO SHOW DECREASING FLOWS
ESPECIALLY IN LOCATIONS THAT HAVE MISSED THE RECENT RAINFALL. THE
MAJORITY OF SOUTH CENTRAL TEXAS WAS REPORTING BELOW AVERAGE STREAM
FLOWS WHILE THE EASTERN HALF REPORTED BELOW TO MUCH BELOW AVERAGE
FLOWS.  (more...)

Texas Water Development Board Meeting Open To Public

September 3rd, 2014 at 7:56 am by under Weather
TWDB_splashLogo_verysmall
FROM:
Texas Water Development Board (TWDB)
WHAT:
The public and interested stakeholders are invited to attend a TWDB Board  meeting.
WHEN:
Thursday, September 4, 2014, at 9:30 a.m.
 
WHERE:
Stephen F. Austin Building   
1700 North Congress Avenue
Room 170
Austin, TX 78701
WHY:
The Board will consider financial assistance for communities looking to address water and wastewater needs within their regions. Communities requesting financial assistance include the cities of Early, Hutto, McAllen, and Los Fresnos, as well as the Beaver Creek Water Control and Improvement District No. 1 and the Lower Colorado River Authority. The Board will also hear an overview of the Texas Natural Resources Information System. 
WHO:
TWDB staff will be on hand to answer questions and accept public comment.

 

HERE IS THE LATEST AREA DROUGHT STATUS MAP COURTESY OF THE US DROUGHT MONITOR:

Drought

Since the last map was issued the “Exceptional” (highest level”  drought status in Gillespie County has expanded a bit.  The “Extreme” drought has spread into Blanco and Llano counties this time around.  Finally, Metro and Eastern conditions have worsenend too.  A few weeks ago, the lowest level of drought, “Abnormally Dry” spread from Travis County through many of our Eastern Areas.  Now, “Moderate” to “Severe” drought statuses have overcome those same spots.

 

TWDB Homepage Link:     http://www.twdb.texas.gov/

 


NASA rainfall observing satellite out of fuel, but continues to provide data

September 1st, 2014 at 7:58 pm by under Weather

Rani Gran, NASA’s Goddard Space Flight Center

Pressure readings from the Tropical Rainfall Measuring Mission‘s (TRMM) fuel tank on July 8 indicated that the satellite was nearly at the end of its fuel supply. As a result, NASA has ceased maneuvers to keep the satellite at its operating altitude of 402 kilometers (~250 miles). With its speed decreasing, TRMM has begun to drift downward. A small amount of fuel remains to conduct debris avoidance maneuvers to ensure the satellite remains safe.

TRMM’s slow descent will continue over the next 2 to 3 years. It will continue to collect useful data as its orbit descends to about 350 (217.5 miles) over the next 18 months. Once TRMM reaches an altitude of 150 to 120 kilometers (93 to 75 miles), it will re-enter the atmosphere.

The TRMM satellite, a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA), was launched in 1997 to measure precipitation over the tropics, carrying the first precipitation radar into space.

“TRMM has met and exceeded its original goal of advancing our understanding of the distribution of tropical rainfall and its relation to the global water and energy cycles,” said Scott Braun, the mission’s project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Its planned three-year mission has already lasted 17 years and provided researchers with an unprecedented data set that combined more traditional radiometer measurements with 3-dimensional radar scans across the tropical ocean and into the lower mid-latitudes from 35N to 35S latitude. Also unique to TRMM is its inclined orbit that allows it to cut across the paths of polar orbiting satellites and revisit locations at different times of day, which is important for understanding how rainfall evolves with the day/night cycle. TRMM provided the first measurements of this type over the tropical ocean.

(more…)