One of Austin’s most important holiday events is the Chuy’s Children Giving to Children Parade in downtown Austin. We are happy to report that the weather will be just fine for this year’s parade, Saturday morning at 11 a.m. Skies may still be cloudy from the early morning hours, but you will be able to leave the jackets at home, as we are expecting unseasonably mild temperatures.
Tonight – November 25, 2014 – the waxing crescent moon and the red planet Mars appear in the southwest sky at nightfall. Be sure to check out these worlds at early evening because they’ll follow the sun beneath the horizon by mid-evening.
While our Earth has one large ball-shaped moon, Mars has two tiny potato-shaped moons. Our moon lies at a mean distance of 384,400 kilometers (238,855 miles), but Mars’ two moons reside very close to the surface of the red planet. Deimos, the smaller of Mars’ two moons, is 23,460 kilometers (14,577 miles) from Mars.
This illustration compares the relative sizes of Mars’ moons as seen from the surface of Mars, with the size of our moon as seen from Earth. Image via NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ.
Phobos, the larger, lies only 9,270 kilometers (5,670 miles) away. These distances are from the center of Mars. These moons lodge closer yet to Mars’ surface.
The closer a moon’s orbit, the faster the moon goes in its orbit around its parent planet. Deimos’ orbital period is 30 hours and 12 minutes. But the orbital period of Phobos, the closer moon, is only 7 hours and 39 minutes. Phobos is one of the very few moons in the solar system to orbit a planet in less time than its parent planet’s rotational period. Mars rotates full circle in 24 hours and 39 minutes, so one day on Mars is only slightly longer than one Earth day.
The synchronous orbit of two artificial satellites. In this image, we’re looking downward at the Earth’s north pole, and the satellites are orbiting above the Earth’s equator. At a distance of 35,786 kilometers above the Earth’s surface (42,164 kilometers from the Earth’s center), the satellites’ orbital periods equal Earth’s rotational period. Image via Wikipedia
The distance at which a moon’s (or an artificial satellite’s) orbital period equals the planet’s rotational period is called the synchronous orbit radius. On Mars, this distance is 17,031 kilometers (10,583 miles) above Mars’ surface, or 20,427 kilometers (12,693 miles) from the center of Mars. Farther away than the synchronous orbit, the moon’s orbital period is longer than the planet’s rotational period. Below the synchronous orbit, the moon’s orbital period is shorter than the planet’s rotation.
Because Phobos circles Mars below the synchronous orbit distance, the orbit of this moon is decaying, with Phobos moving closer to Mars at the rate of about 1.8 meters (6 feet) per century. Astronomers believe Phobos is doomed to crash into Mars or to break up into a ring of rubble in about 50 million years.
At a distance of 60 Earth-radii (384,400 kilometers), our moon resides at roughly 9 times the Earth’s synchronous orbit radius of 6.6 Earth-radii (42,000 kilometers from the Earth’s center). At present, the moon is retreating from Earth at the rate of about 3.8 meters (12.5 feet) per century.
Bottom line: On the evening of November 25, 2014, as darkness falls, watch for the picturesque pairing of the waxing crescent moon with the red planet Mars.
By John S. Jensenius, Jr., NWS Lightning Safety Specialist
Lightning is one of the top three storm-related killers in the United States. It is also one of the least understood weather phenomena. The Overview Section gives a brief introduction to lightning science and safety. Want to learn more? In the Understanding Lightning Section, you can find a more detailed look at the science behind one of nature’s most underrated killers.
- Thunderstorm Development
- Thunderstorm Electrification
- Types of Flashes
- Initiation of Leaders
- Negatively-Charged Flash:
- Positive Flash
- Upward Leaders/Discharges
- Continuing Current/Hot Lightning
- Acknowledgements And References
Here is a map of estimated rainfall across South Central Texas from the previous 48 hours ending at midnight. Many locations across the eastern half of the area received over 2 inches of rain with a swath of 4+ inches from New Braunfels to San Marcos to Austin.
Click here for more rainfall totals. NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
...48 HOUR RAINFALL REPORTS ENDING 10 AM CST SUNDAY...
LOCATION AMOUNT TIME/DATE LAT/LON
TOM MILLER DAM 4.39 IN 1000 AM 11/23 30.17N/97.47W
SMITHVILLE 0.9 E 3.73 IN 0853 AM 11/23 30.01N/97.14W
PAIGE 4.6 SW 3.55 IN 0824 AM 11/23 30.16N/97.16W
SMITHVILLE 3.51 IN 1010 AM 11/23 30.01N/97.16W
SMITHVILLE 3.12 IN 0800 AM 11/23 30.02N/97.15W
Here is a breakdown of the potential severe weather threats for this Saturday, November 22nd. The greatest severe threat will be large hail, but damaging straight line winds and a few tornadoes are also possible. Some storm training is possible with locally heavy rainfall amounts of 1 to 2 inches possible. The severe threat will be primarily along and east of a Rocksprings to Carrizo Springs line and between the hours of Noon and 9 PM CST.
Rainfall totals through Saturday night are expected to range from light amounts across the western counties to near 1-2 inches across the northeastern counties. There could be isolated 4 inch rain totals for locations near Austin, Burnet and La Grange.
- Strong to severe thunderstorms with large hail, damaging winds and heavy rainfall.
- Isolated Tornadoes with a few Supercells possible.
- Rainfall totals 1-2 inches, isolated 4 inches possible. Rain Rates of 1 to 2 inches per hour in heavier storms.
- Mainly minor urban flooding possible. Higher totals may cause isolated flash flooding concerns.
If you missed our KXAN First Warning Weather in-depth report on the new winter outlook, watch it by clicking here.
Here is a look at the system that is going to bring us widespread rain and the chance for severe weather. Currently, the potent upper low is over the northern Pacific Ocean off the coast of California. By Friday morning, the upper low will be over Southern California and by Saturday morning the low will be over West Texas.
Here is the Storm Prediction Center’s convective outlook for Saturday. There is an enhanced risk for severe thunderstorms across the eastern half of South Central Texas. The main threat will be damaging wind gusts with a chance for tornadoes and large hail.
- Strong to severe thunderstorms with large hail, damaging winds and heavy rainfall.
- Isolated Tornadoes with a few Supercells possible.
- Rainfall totals of 1/2 to 1 inch. Isolated totals to 2 inches. Rain Rates of 1 to 2 inches per hour in heavier storms.
- Mainly minor urban, nuisance type flooding for the San Antonio and Austin metro areas expected at this time. However, we will need to watch areas along and east of I-35 carefully for heavier rainfall amounts.
The following is an excerpt from a Dr. Jeff Masters blog post on Weather Underground:
This week’s intense cold blast is being triggered by an unusually extreme jet stream pattern, featuring a sharp ridge of high pressure along the U.S. West Coast and a deep trough of low pressure diving to the south over the Central United States. This configuration allows cold air to spill out of the Arctic behind the trough into the Central U.S., and be replaced by anomalously warm air flowing northwards along the West Coast of the U.S. deep into the Arctic. This extreme jet stream pattern is due, in part, to the influence of Super Typhoon Nuri, which caused a ripple effect on the jet stream after the typhoon became one of the most powerful extratropical storms ever recorded in the waters to the west of Alaska eleven days ago. However, we’ve seen an unusual number of extreme jet stream patterns like this in the past fifteen years, which happens to coincide with the period of time we’ve been observing record loss of summertime Arctic sea ice and record retreat of springtime snow cover in the Arctic. Could it be that these changes in the Arctic are causing the wacky jet stream behavior of recent years? That’s the theory being advanced by a number of prominent climate scientists. I’ve written extensively about the topic, and my most recent post on the subject was in April, California Drought/Polar Vortex Jet Stream Pattern Linked to Global Warming. A updated story that I wrote for the just-published December issue of Scientific American discusses the theory and its detractors, and you can read it on-line for $6 (or buy a copy at the news stand.) My conclusion in the article: If Arctic changes are truly to blame for wacky jet stream behavior, losing the remaining 50 percent of the Arctic sea-ice coverage between now and 2030 will bring even greater antics. If the Arctic is not involved, that is worrisome as well—because that means jet stream changes are due to an unknown mechanism, leaving us with no idea how the jet stream will respond as climate change progresses. Thus, my forecast for the next 15 years: expect the unprecedented.
Historic Action Prompted by Record-Setting Drought
With parts of Texas in the midst of a persistent, severe drought, the Lower Colorado River Authority will seek permission from the state to curtail releases of interruptible stored water from the Highland Lakes for downstream irrigation for the fourth year in a row.
LCRA also will ask permission to reduce the amount of water required to be released in spring 2015 to support the habitat of the blue sucker, a threatened fish that lives in the river downstream of Austin.
“This was not an easy decision, but we must protect the region’s water supply,” said LCRA General Manager Phil Wilson. “More than a million people depend on water from the Highland Lakes, and right now, there is just not enough water for everyone to have all they want.
“This is a significant drought. At times, it’s been even more intense than the worst recorded drought in this region’s history, and we don’t know when it’s going to end,’’ Wilson said. “This action will help us manage our limited water supply to meet the essential needs of the region’s communities and industries.”
On Wednesday, the LCRA Board of Directors voted 11-2 to ask permission from the Texas Commission on Environmental Quality to curtail releases from the lakes in 2015.
LCRA is requesting drought relief identical to the relief approved by TCEQ for 2014, which cut off releases of interruptible water supplies for most downstream irrigation.
The Board said it also would continue limiting outdoor watering by LCRA firm customers and their customers to a maximum of one day a week. Firm customers include cities in Central Texas that depend on water from the Highland Lakes.
For the third month in a row, global temperatures reached record territory according to newly available data from NASA. And if one global temperature record isn’t enough, the Japanese Meteorological Agency also provided new data on Friday that showed the warmest October on record.
Global temperature anomalies for the month of October compared to 1951-1980 average.
Credit: NASA GISS
Data from NASA Goddard Institute for Space Studies (GISS) show this October was 1.4°F above the 1951-1980 average they use as their baseline. That didn’t set a monthly mark, as did August and September, but rather tied 2005 as the warmest October since 1880. That keeps 2014 on track to be the hottest year on record.
While individual hot years or months don’t necessarily stand out, it’s notable that all 10 of the warmest years on record have all come since 1998, one of the clearest signs that the climate is warming due in large part to greenhouse gas emissions.
|RELATED||2014 on Track to be Hottest Year on Record
Climate Change Is Increasing Extreme Heat Globally
Waiting for El Niño. Still. Again.
NASA data reveal that far eastern Siberia was an eye-popping 10°F above normal for October, but western Europe, northern Africa and western North America also saw temperatures up to 7°F hotter than average. The data also comes a day after the National Climatic Data Center (NCDC) released its October numbers for the U.S. that showed the lower 48 had its fourth-warmest October on record.
What to watch for in November: Species on the move
Here’s the Central Texas bird forecast for the month, courtesy of Travis Audubon. Learn more about Central Texas birds and bird-related events for all ages at travisaudubon.org or by calling 512-300-BIRD. Travis Audubon is on Twitter and Facebook. Follow us on Twitter @TravisAudubon and give us a like at www.facebook.com/travisaudubon.
Welcome, winter Texans
Certain species will continue arriving in Texas over the coming weeks to spend the winter here. North winds make their journeys less energy-intensive. Texas provides critical habitat for these “winter Texans.”
Songbirds arriving include the Hermit Thrush, Dark-eyed Junco, Chipping Sparrow, White-crowned Sparrow, White-throated Sparrow, Vesper Sparrow and American Pipit. Ducks are also winging south. Watch the duck populations swell on area lakes and ponds. Look for Ring-necked Duck, Lesser Scaup, Hooded Merganser, Gadwall, Redhead and Canvasback.
The Ring-necked Duck is oddly named since the ring is not around the collar but around the bill. The males of these diving ducks have jet-black heads. The females are more tan and gray, but both have gray bills with white ring near the black tips. Both also have sloped foreheads and flattened crowns, which gives them a pointy-headed look. Look for them on smaller ponds, not large bodies of water.
Speaker: Jeff Parker
Location: Hyde Park Christian Church, 610 E 45th St., Austin, TX 78751 Come prepared to enjoy some great wildlife photos as photographer Jeff Parker talks about the value of wildlife photography and photo contests in increasing awareness of our natural heritage. Parker, an award-winning naturalist photographer and certified wildlife guide, will talk about how wildlife photography has opened the eyes of some landowners to other wildlife on their property, giving them an incentive to protect the native wildlife of our state.
Indiangrass Wildlife Sanctuary with Robert Reeves and Rene’ Barrera
Saturday, November 8, 8 to 11 a.m.
Monthly Bird Count at Hornsby Bend
Saturday, November 8, 7 a.m. and 4 p.m.
Balcones Canyonlands NWR
Sunday, November 9, 7:30 to 11:30 a.m.
Super Tuesday at Northeast Metropolitan Park, led by Dan Callaway
Tuesday, November 11, 7:30 to 11:30 a.m.
Hornsby Bend Monthly Bird Walk
Saturday, November 15, 7:30 to 11 a.m.
Super Tuesday at Pedernales Falls State Park, led by Terry Banks
Tuesday, November 18, 6:30 a.m. to noon
Balcones Canyonlands/Water Quality Preserves-Part 3
Friday, November 21, 8 to 11 a.m.
Laguna Gloria with Dennis Palafox and Jane Tillman
Saturday, November 22, 7:30 to 11:30 a.m.
Super Tuesday at Tejas Camp, led by Ray and Ginny Steelman
Tuesday, November 25, 6:45 a.m. to noon
Commons Ford Monthly Walk
Sunday, November 30, 7:30 to 11:00 a.m.
Compiled by Travis Audubon volunteers Jane Tillman and Raeanne Martinez