Another winter storm system on the way; icy roads possible

March 3rd, 2015 at 3:31 pm by under Weather

Also see the post below for more specifics regarding the approaching winter storm system.


A strong cold front will move through south central Texas on Wednesday. Much colder air will follow behind the cold front with sub-freezing temperatures reaching the Hill Country in the evening. The cold air continues to plunge southward overnight with sub- freezing temperatures reaching a Del Rio to near San Antonio to Giddings line by sunrise Thursday morning. A wintry mix of freezing rain and sleet is expected to begin Wednesday evening in the Hill Country, then drop southward to near the U.S. Highway 90 corridor. The best chance for accumulations of ice will be across the Hill Country and the Interstate 35 corridor northeast of San Antonio. Please continue to monitor the forecast for the latest information and updates regarding this potential winter weather event.
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Updated statement from the National Weather Service:

Headline:

…Frozen precipitation possible late Wednesday evening through Thursday morning…

Area of Concern:

Cold Arctic Air - All of South Central Texas

Frozen Precipitation - The Hill Country, areas northwest of San Antonio, and northern parts of the I-35 corridor including the Austin metro area (Travis and Williamson Counties).

Threats & Impacts:

Ice Accumulations: There is a high likelihood the Hill Country will see ice accumulations.  It is too early to tell exactly how much.  As in the previous winter events, areas farther east, including the I-35 corridor, will have a threat for icing but temperatures may not be cold enough to support widespread ice development except on bridges and overpasses.

Impacts:  Bridge/overpass closures, some ice on less traveled roads, and numerous traffic accidents. At this time we are not expecting significant ice accumulation on tree branches or power lines.

Timing and Overview:

6 PM Wednesday through Noon Thursday.

An upper level storm system will bring high precipitation chances Wednesday morning through Thursday morning. Strong upper level winds will generate stronger lift than previous systems, so some scattered thunderstorms will be possible during the day Wednesday before the front arrives. The Arctic front will arrive in Wednesday afternoon. Temperatures behind the front will fall drastically, with the Hill Country reaching freezing around 9 pm Wednesday. Northern portions of the I-35 corridor will fall below freezing shortly after midnight, including the Austin metro area.

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Risk of icy roads in some areas early Thursday

March 3rd, 2015 at 7:38 am by under Weather

3-3 snow ice fcast

Following a brief warm-up today and early Wednesday afternoon, we are tracking our next blast of Arctic air set to bring yet another threat of ice and snow.

The cold air is forecast to arrive late Wednesday afternoon. As a storm system approaches Texas from the west, moisture overriding the cold air will increase cold rain Wednesday evening–eventually turning to freezing rain and sleet in many communities along and west of I-35.

wpc bllog

Current National Weather Service forecasts indicate a 40-50% chance of accumulating ice on elevated roads in the Austin metro area early Thursday.

Here’s what our partners at the National Weather Service in New Braunfels have to say:

Headline:

…Another round of frozen precipitation is possible Wednesday evening through Thursday morning…

Area of Concern:

Cold Arctic Air - All of South Central Texas

Frozen Precipitation - Mainly the Hill Country, areas northwest of San Antonio,  and northern parts of I-35 corridor including the greater Austin metro area (Travis and Williamson Counties).

Threats & Impacts:

Ice Accumulations: There is a high likelihood that areas of the Hill Country will see ice accumulations.  It is too early to tell exactly how much.  As in the previous winter events the past several weeks, areas farther east including the I-35 corridor will have a threat for icing but temperatures may not be cold enough to support widespread ice development outside of bridges and overpasses. Stay tuned, that could change.

Impacts:  Mainly travel impacts expected at this time.  Bridge/overpasses closures, some ice on less traveled roads. Numerous traffic accidents.  At this time we are not expecting widespread power outages.

Timing and Overview:

6 PM Wednesday through Noon Thursday.

The next front will arrive in South Central Texas Wednesday Afternoon with an arctic airmass behind it. Temperatures will fall behind the front with the Hill Country reaching freezing around 9 pm Wednesday. Northern Portions of the I-35 corridor will fall below freezing shortly after midnight…this includes the Austin metro area. An upper level storm system will create high precipitation chances Wednesday morning through Thursday morning. Due to the upper level winds we will get more lift with this weather system than previous systems, so some scattered thunderstorms will be possible during the day Wednesday before the front arrives.

Based on our current forecast a Sleet and Freezing Rain mix will begin across the Hill Country Wednesday night stretching from a Del Rio to San Antonio to Giddings line by midnight. This will then transition over to a sleet and snow mix by Thursday morning for areas north of Highway 90. As in past events the best chance for ice accumulation and impacts will be in the Hill Country and along the northern I-35 corridor where temperatures will be coldest. Temperatures are expected to warm above freezing by noon on Thursday and rain chances begin to taper off Thursday afternoon.

The question of just how much precipitation will fall, the exact type of precipitation, and just how far south the freezing line will get, are all still questions that are being fine tuned with each forecast package. As in past events this year, far southern and eastern areas will likely just see cold rain, western and northern areas (higher terrain) will probably get some ice, and areas in the middle (I-35 from San Antonio to Austin) will be stuck in the middle and could go either way.  In cases like this, many times I-35 is literally a dividing line…colder air and ice chances in the hills, and cold rain east of I-35.  Where it is forecast to be cold enough…such as the Hill Country, we can expect some ice formation especially on exposed surfaces like bridges and overpasses.

Watch the forecast closely over the next few days…there will likely be adjustments to the above forecast information.  There is a high likelihood that portions of the area will be under some sort of winter weather advisory/watch/warning during this Wed Evening - NoonThu time frame.

Confidence:

Arctic Air – High

Frozen Precipitation Amounts/Area - Moderate

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Currently, forecast low temperatures in Austin will support patchy, but not widespread, icing during the Thursday morning commute. Stay tuned for updates on KXAN, KXAN.com, and our free KXAN Weather app on your smartphone.


Another bout of icy weather possible Wednesday night – Thursday

March 2nd, 2015 at 8:49 pm by under Weather

Another round of wintry precipitation and cold weather is expected Wednesday night and Thursday morning. Plan now for potentially icy roads, especially in the Hill Country and northern areas on the plains. Any travel plans during that period should be reconsidered if conditions develop as expected. Check back often over the next few days for the latest updates.

Antarctic’s retreating ice may re-shape earth

March 2nd, 2015 at 2:19 pm by under Weather
AP Photo

AP Photo

CAPE LEGOUPIL, Antarctica (AP) — From the ground in this extreme northern part of Antarctica, spectacularly white and blinding ice seems to extend forever. What can’t be seen is the battle raging thousands of feet (hundreds of meters) below to re-shape Earth.

Water is eating away at the Antarctic ice, melting it where it hits the oceans. As the ice sheets slowly thaw, water pours into the sea – 130 billion tons of ice (118 billion metric tons) per year for the past decade, according to NASA satellite calculations. That’s the weight of more than 356,000 Empire State Buildings, enough ice melt to fill more than 1.3 million Olympic swimming pools. And the melting is accelerating.

In the worst case scenario, Antarctica’s melt could push sea levels up 10 feet (3 meters) worldwide in a century or two, recurving heavily populated coastlines.

Parts of Antarctica are melting so rapidly it has become “ground zero of global climate change without a doubt,” said Harvard geophysicist Jerry Mitrovica.

Here on the Antarctic peninsula, where the continent is warming the fastest because the land sticks out in the warmer ocean, 49 billion tons of ice (nearly 45 billion metric tons) are lost each year, according to NASA. The water warms from below, causing the ice to retreat on to land, and then the warmer air takes over. Temperatures rose 5.4 degrees Fahrenheit (3 degrees Celsius) in the last half century, much faster than Earth’s average, said Ricardo Jana, a glaciologist for the Chilean Antarctic Institute.

As chinstrap penguins waddled behind him, Peter Convey of the British Antarctic Survey reflected on changes he could see on Robert Island, a small-scale example and perhaps early warning signal of what’s happening to the peninsula and rest of the continent as a whole.

“I was last here 10 years ago,” Convey said during a rare sunny day on the island, with temperatures just above freezing. “And if you compare what I saw back then to now, the basic difference due to warming is that the permanent patches of snow and ice are smaller. They’re still there behind me, but they’re smaller than they were.”

Robert Island hits all the senses: the stomach-turning smell of penguin poop; soft moss that invites the rare visitor to lie down, as if on a water bed; brown mud, akin to stepping in gooey chocolate. Patches of the moss, which alternates from fluorescent green to rust red, have grown large enough to be football fields. Though 97 percent of the Antarctic Peninsula is still covered with ice, entire valleys are now free of it, ice is thinner elsewhere and glaciers have retreated, Convey said.

Dressed in a big red parka and sky blue hat, plant biologist Angelica Casanova has to take her gloves off to collect samples, leaving her hands bluish purple from the cold. Casanova says she can’t help but notice the changes since she began coming to the island in 1995. Increasingly, plants are taking root in the earth and stone deposited by retreating glaciers, she says.

“It’s interesting because the vegetation in some way responds positively. It grows more,” she said, a few steps from a sleeping Weddell seal. “What is regrettable is that all the scientific information that we’re seeing says there’s been a lot of glacier retreat and that worries us.”

Just last month, scientists noticed in satellite images that a giant crack in an ice shelf on the peninsula called Larsen C had grown by about 12 miles (20 kilometers) in 2014. Ominously, the split broke through a type of ice band that usually stops such cracks. If it keeps going, it could cause the breaking off of a giant iceberg somewhere between the size of Rhode Island and Delaware, about 1,700 to 2,500 square miles (4,600 to 6,400 square kilometers), said British Antarctic Survey scientist Paul Holland. And there’s a small chance it could cause the entire Scotland-sized Larsen C ice shelf to collapse like its sister shelf, Larsen B, did in a dramatic way in 2002.

A few years back, scientists figured Antarctica as a whole was in balance, neither gaining nor losing ice. Experts worried more about Greenland; it was easier to get to and more noticeable, but once they got a better look at the bottom of the world, the focus of their fears shifted. Now scientists in two different studies use the words “irreversible” and “unstoppable” to talk about the melting in West Antarctica. Ice is gaining in East Antarctica, where the air and water are cooler, but not nearly as much as it is melting to the west.

“Before Antarctica was much of a wild card,” said University of Washington ice scientist Ian Joughin. “Now I would say it’s less of a wild card and more scary than we thought before.”

Over at NASA, ice scientist Eric Rignot said the melting “is going way faster than anyone had thought. It’s kind of a red flag.”

What’s happening is simple physics. Warm water eats away at the ice from underneath. Then more ice is exposed to the water, and it too melts. Finally, the ice above the water collapses into the water and melts.

Climate change has shifted the wind pattern around the continent, pushing warmer water farther north against and below the western ice sheet and the peninsula. The warm, more northerly water replaces the cooler water that had been there. It’s only a couple degrees Fahrenheit warmer than the water that used to be there, but that makes a huge difference in melting, scientists said.

The world’s fate hangs on the question of how fast the ice melts.

At its current rate, the rise of the world’s oceans from Antarctica’s ice melt would be barely noticeable, about one-third of a millimeter a year. The oceans are that vast.

But if all the West Antarctic ice sheet that’s connected to water melts unstoppably, as several experts predict, there will not be time to prepare. Scientists estimate it will take anywhere from 200 to 1,000 years to melt enough ice to raise seas by 10 feet, maybe only 100 years in a worst case scenario. If that plays out, developed coastal cities such as New York and Guangzhou could face up to $1 trillion a year in flood damage within a few decades and countless other population centers will be vulnerable.

“Changing the climate of the Earth or thinning glaciers is fine as long as you don’t do it too fast. And right now we are doing it as fast as we can. It’s not good,” said Rignot, of NASA. “We have to stop it; or we have to slow it down as best as we can. `’

Associated Press writer Luis Andres Henao reported this story from various locations in Antarctica and Seth Borenstein reported from Washington.

 



An Early Look At Our Next Chance For Ice

March 1st, 2015 at 8:30 pm by under Weather

Here is the latest from the National Weather Service, regarding the possibility of Central Texas ice…… Again….

Remember, it is only Sunday evening, and models will most likely shift timing, and the freezing line location by Wednesday evening.  Therefore, keep an eye on the forecast between now, and the middle of this week.  We’ll have numerous up to the minute updates on KXAN, KXAN.com, and on our KXAN Weather App.  Have a great week and stay warm!!

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Another strong arctic front is scheduled to move through the area Wednesday afternoon. Showers and thunderstorms will be possible ahead and just behind the front, but as cold air filters into the area, freezing rain/sleet/snow will be possible for areas in white. It is too early to get into specifics regarding accumulations and impacts, but areas north of the pink line will see the coldest temperatures. Stay tuned over the next few days for updates as confidence increases one way or the other


Last Update On The Wintry Weather From NWS

February 28th, 2015 at 3:39 pm by under Weather
All Winter Storm Warnings and Winter Weather Advisories along and south of a Kerr to Llano to Williamson County line have been allowed to expire.  
 **WINTER WEATHER ADVISORIES continue for Mason and San Saba Counties through 6PM Saturday**
Overview:
Temperatures have risen above freezing across Travis and Williamson counties.  Temperatures are still below freezing across some areas of the northern Hill Country.  There could still be some patchy light freezing rain or freezing drizzle along and north of a Marble Falls to Blanco to Kerrville line through the remainder of the afternoon.  Any additional accumulation amounts are expected to be very light.  However, those traveling through the region should still exercise caution due to earlier icing this morning, especially over bridges and overpasses.  Elsewhere, patchy drizzle and light rain will continue today through tomorrow.  Temperatures tonight rising across the Hill Country into the mid and upper 30s, and elsewhere in the 40s. 
 
Next Week:
A heads up for next week, weather models have been indicating another possibility of wintry precipitation Wednesday night into Thursday morning across the Hill Country and Central Texas.  At this time it is too soon to determine with high certainty the precipitation type, exact amounts and exact locations.  However, stay tuned next week for potential email briefings if trends continue towards another round of winter precipitation.
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Latest wintry weather update

February 28th, 2015 at 9:16 am by under Weather

A Winter Storm Warning is in effect until noon for Travis and Williamson counties, where 1/10″ ice accumulation is possible on heavily-traveled metro roadways. A Winter Weather Advisory is highlighted elsewhere in pink: Hays and Blanco counties will expire at 10 AM on Saturday, and all other counties are set to expire at noon. With temperatures rising into the 40s everywhere this afternoon, the First Warning Weather Team does not anticipate that any watches, warnings or advisories will be issued after that time.

2-28 WWA

 

Here is the latest from the National Weather Service:

Stay off the roadways before noon if possible. Even though temperatures should rise above freezing in the metro and Hill Country between 10 AM and noon, early morning ice will still take some time to melt off the streets. Exposed and elevated areas will bear the brunt of the icy impacts: bridges, toll roads, overpasses, patios and walkways.


Latest NWS Update For The Winter Weather Advisory

February 27th, 2015 at 5:40 pm by under Weather
1 SPC
A Winter Weather Advisory is in effect until 10 am Saturday for the entire Hill country, I-35 corridor, Metro Austin, and Metro San Antonio. Numerous Reports of Icing across Williamson, Burnet, and Gillispie County. 
Area of Concern:
The primary area will be roughly from Taylor in eastern Williamson County to the southwest border of Bexar County, and along and west of U.S. 90 from San Antonio to Del Rio. This does include All of Metro Austin and Metro northern San Antonio.
 
Threats & Impacts:

Expected Accumulations: We expect light amounts of 1/10 inch or less freezing drizzle in the advisory area.
Impacts:  The primary impacts are expected to be slippery spots, primarily on bridges, overpasses, less traveled roads, and other elevated surfaces (e.g., backyard decks).
Timing and Overview:
Freezing drizzle is on the increase at the present time and numerous reports of icing mainly on bridges and overpasses have come into the office. In the attached image, most of the moderate impacts have been in the yellow shaded region. Locations in the pink area can quickly see impacts as the night progresses. The most significant impacts will be where temperatures have dropped below 30 degrees. Precipitation is light but it only takes a little to cause moderate impacts of ice. The freezing drizzle should continue for most of the night with a nearly steady temperature. Temperatures should warm above freezing around 9-10 AM Saturday morning. 
Confidence:
High for the temperatures being cold, High for freezing precipitation and amounts.
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NWS

Latest wintry weather update

February 27th, 2015 at 9:30 am by under Weather

Though the Austin metro area has been pulled out of the threat for wintry precipitation for today and tomorrow, the Hill Country may still have some slick spots by Saturday morning. Here’s the latest breakdown from our friends at the National Weather Service:

Headline:

Another round of wintry mixed precipitation on the way from this morning through 10 am Saturday for higher elevations in the Hill Country, and the far western portion of Williamson County.

Area of Concern:

The primary area will be the Hill Country, roughly from Burnet to Fredericksburg to Kerrville to Rocksprings. Another area of concern is is the far western end of Williamson County, from Florence down to Liberty Hill. Metro Austin, the I-35 corridor, and Metro San Antonio are now completely out of the winter weather threat.

Threats & Impacts:

Expected Accumulations: We expect very light amounts — 1/4 inch or less of snow in the Hill Country, accompanied by only a few hundredths of sleet or freezing rain/drizzle in that area, and in far western Williamson County.

Impacts:  The primary impacts are expected to be patchy slippery spots, primarily on bridges, overpasses, and other elevated surfaces (e.g., picnic tables).

Timing and Overview:

Moist Gulf air will continue to lift over cold air near the ground to produce the wintry mix of precipitation. As with the other events this winter, we expect precipitation amounts to be light, and generally be more of a travel nuisance than any threat to safety. All of the precipitation should end by 10 am on Saturday, and temperatures will warm above freezing then. Please see the graphics below.

Confidence:

High for the temperatures being cold, High for the precipitation mix and amounts.

Stay in touch with the latest weather forecasts on KXAN.com.


Warmer weather for ABC Zilker Kite Festival

February 26th, 2015 at 5:38 pm by under Weather

The good news for the ABC Zilker Kite Festival is that the weather will be much warmer, with only a slight chance for rain showers. This coming a year after the event was rained out on two successive weekends. There may not be much sun, or a lot of wind, but hopefully enough to launch the hundreds of kites expected at the park.

2-26 Kite FX