Weather

More rainfall expected this week

July 15th, 2014 at 10:43 pm by under Weather

Many areas enjoyed beneficial rainfall Tuesday, and we are expecting more this week. We will likely see a bit of a lull Wednesday, but an upper level disturbance will bring another good chance of showers and thunderstorms by Thursday, into Friday.

Click here to see Tuesday’s rainfall totals.


Locally heavy rain of 1 to 2 inches in a short period of time may occur with storms on Thursday and Friday. This may result in localized minor flooding. As always, do not drive where water covers the road. Turn Around, Don’t Drown.

Kaxan reminds you to protect your pet from summer heat

July 14th, 2014 at 3:50 pm by under Weather

Kaxan found this great video online from Discovery News he wants to share with everyone. It is about keeping your pets cool in the summer. Click here to check it out!

car heat

Please read this important information from the Humane Society of the United States:

The summer months can be uncomfortable—even dangerous—for pets and people. It’s difficult enough simply to cope with rising temperatures, let alone thick humidity, but things really get tough in areas that are hit with the double blow of intense heat and storm-caused power outages, sometimes with tragic results.

We can help you keep your pets safe and cool this summer. Follow our tips for helping everyone in your family stay healthy and comfortable when the heat is on (and even if the power isn’t).

Practice basic summer safety

Never leave your pets in a parked car

Not even for a minute. Not even with the car running and air conditioner on. On a warm day, temperatures inside a vehicle can rise rapidly to dangerous levels. On an 85-degree day, for example, the temperature inside a car with the windows opened slightly can reach 102 degrees within 10 minutes. After 30 minutes, the temperature will reach 120 degrees. Your pet may suffer irreversible organ damage or die. Learn how to help a pet left inside a hot car »

Print our hot car flyer [PDF] and spread the life-saving word »

Watch the humidity

“It’s important to remember that it’s not just the ambient temperature but also the humidity that can affect your pet,” says Dr. Barry Kellogg, VMD, of the Humane Society Veterinary Medical Association. “Animals pant to evaporate moisture from their lungs, which takes heat away from their body. If the humidity is too high, they are unable to cool themselves, and their temperature will skyrocket to dangerous levels—very quickly.”

Taking a dog’s temperature will quickly tell you if there is a serious problem. Dogs’ temperatures should not be allowed to get over 104 degrees. If your dog’s temperature does, follow the instructions for treating heat stroke.

Limit exercise on hot days

Take care when exercising your pet. Adjust intensity and duration of exercise in accordance with the temperature. On very hot days, limit exercise to early morning or evening hours, and be especially careful with pets with white-colored ears, who are more susceptible to skin cancer, and short-nosed pets, who typically have difficulty breathing. Asphalt gets very hot and can burn your pet’s paws, so walk your dog on the grass if possible. Always carry water with you to keep your dog from dehydrating.

Don’t rely on a fan

Pets respond differently to heat than humans do. (Dogs, for instance, sweat primarily through their feet.) And fans don’t cool off pets as effectively as they do people.

Provide ample shade and water

Any time your pet is outside, make sure he or she has protection from heat and sun and plenty of fresh, cold water. In heat waves, add ice to water when possible. Tree shade and tarps are ideal because they don’t obstruct air flow. A doghouse does not provide relief from heat—in fact, it makes it worse.

Cool your pet inside and out

Whip up a batch of quick and easy DIY peanut butter popsicles for dogs. (You can use peanut butter or another favorite food.) And always provide water, whether your pets are inside or out with you.

Keep your pet from overheating indoors or out with a cooling body wrap, vest, or mat (such as the Keep Cool Mat). Soak these products in cool water, and they’ll stay cool (but usually dry) for up to three days. If your dog doesn’t find baths stressful, see if she enjoys a cooling soak.

Watch for signs of heatstroke

Extreme temperatures can cause heatstroke. Some signs of heatstroke are heavy panting, glazed eyes, a rapid heartbeat, difficulty breathing, excessive thirst, lethargy, fever, dizziness, lack of coordination, profuse salivation, vomiting, a deep red or purple tongue, seizure, and unconsciousness.

Animals are at particular risk for heat stroke if they are very old, very young, overweight, not conditioned to prolonged exercise, or have heart or respiratory disease. Some breeds of dogs—like boxers, pugs, shih tzus, and other dogs and cats with short muzzles—will have a much harder time breathing in extreme heat.

How to treat a pet suffering from heatstroke

Move your pet into the shade or an air-conditioned area. Apply ice packs or cold towels to her head, neck, and chest or run cool (not cold) water over her. Let her drink small amounts of cool water or lick ice cubes. Take her directly to a veterinarian.

Prepare for power outages

Before a summer storm takes out the power in your home, create a disaster plan to keep your pets safe from heat stroke and other temperature-related trouble.


From triple digits to potentially flooding rain

July 14th, 2014 at 10:17 am by under Weather

After triple-digit heat in many communities Sunday and again Monday, a major pattern change is in store featuring cooler temperatures and the chance of beneficial rainfall.

Courtesy of the National Weather Service

Courtesy of the National Weather Service

An unusual July cold front sweeping down the Plains today is forecast to stall over northern Texas Tuesday and Wednesday, then progress through Central Texas Thursday and Friday.

While the front is to our north, we can expect scattered showers and thunderstorms Tuesday and Wednesday.

Rain chances will increase with the front’s passage, currently forecast to occur overnight Thursday into Friday morning.

Moisture is forecast to “pool” along the frontal boundary, setting up a tropical atmosphere and the potential of heavy rainfall.

We always welcome beneficial rain during a drought, but as happens all too often in Central Texas, the potential does exist for getting too much in too little time.

96          102

The images above show the forecast rainfall (radar) picture overnight Thursday into Friday morning.

Computer models are suggesting the possibility of a complex of heavy thunderstorms forming along the front as it moves through Central Texas.

It is important to note that much uncertainty still exists, as this event is still 3-4 days away. Stay tuned to KXAN and KXAN.com as we continue to draw a clearer picture of this late-week rainfall.


Triple digit heat Sunday a first for 2014

July 13th, 2014 at 9:32 pm by under Weather

Sunday was Austin’s first 100 degree day of 2014. It arrived just three days past the average first 100 degree day, July 10th. The last time Camp Mabry recorded 100 degrees or higher was September 7, 2013.

With another 100 degree day in the works, it’s a good time to review summer heat safety.

Sunday sunset over Lake Travis. (KXAN)

Sunday sunset over Lake Travis. (KXAN)

Here’s some really great information from NOAA.

If you plan on being out and about in summer, chances are you’ll be exposed to a lot of sun and higher temperatures.

Each year, heat kills at least 650 people on average in the United States — more than tornadoes, hurricanes, floods, lightning, or any other weather event combined.

“Heat can be a silent killer because it doesn’t topple trees or rip roofs off houses like tornadoes and hurricanes,” says Eli Jacks, chief of fire and public weather services with NOAA’s National Weather Service. “Nevertheless, it’s a dangerous weather condition for which people should prepare.”

How much heat can a person safely endure? It depends.

Certain groups of people should be especially careful during hot weather conditions. For example, city-dwellers and those living in the upper floors of tall buildings or in heat-prone regions are most at-risk for heat-related illness. People who have difficulty getting around or who have health conditions are particularly susceptible. The elderly and the very young also merit special attention during periods of high heat and humidity.

The National Weather Service and the Occupational Safety and Health Administration have partnered again this year to increase awareness for outdoor workers and their employers during excessive heat events. As part of this effort, the National Weather Service will incorporate specific outdoor worker safety precautions when heat advisories and warnings are issued.

By taking some precautions, you can stay healthy while enjoying the great outdoors this summer:

1. Be informed and stay alert

Pay close attention to heat advisories or warnings that have been issued for your community.

  • NOAA’s National Weather Service continually updates heat-related advisories and warnings online at weather.gov. (Click on “Excessive Heat Warning” and “Heat Advisory” under the U.S. map — if there are no current warnings or advisories in the United States, nothing will appear).
  • NOAA issues excessive heat warnings when weather conditions pose an imminent threat to life and heat advisories when weather conditions are expected to cause significant discomfort or inconvenience or — if caution is not taken — become life threatening.
  • If you do not have Internet access, you can get heat advisory and warning information by watching your local television or radio newscast or by purchasing a NOAA weather radio and tuning into NOAA Weather Radio All-Hazards.
  • Use the temperature and humidity to figure out the heat index for your area, a measure that tells us how hot it feels.

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100-degree day statistics

July 13th, 2014 at 9:38 am by under Weather

Sunday is forecast to bring Austin’s first 100-degree day of 2014 – but it comes a bit later than average.

Here’s some useful ‘heat climatology’, courtesy of our local National Weather Service office.

083007_hot_thermometer

90 and 100 Degree Day Information

The average date of the first and last 90 and 100 degree days

The number of 90 and 100 degree days in a year

And the extremes

…are listed below for Austin, Del Rio and San Antonio.

This is based on daily data for Austin Mabry beginning in 1989, for Austin Bergstrom beginning in 1943, for Del Rio beginning in 1906, and for San Antonio beginning in 1885.

SUMMARY OF 90 DEGREE INFORMATION…

LOCATION, AVERAGE, 90 RECORD, AVG. FIRST, AVG. LAST, EARLIEST/LATEST DEG. DAYS

AUSTIN MABRY - 108.8 164 IN 2011 Apr. 18 Oct. 11 Jan. 30 /Dec. 25
AUSTIN BERGSTROM - 104.8 162 IN 2011 Apr. 19 Oct. 14 Feb. 17 /Dec. 25
DEL RIO - 125.3 171 IN 2011 Mar. 20 Oct. 15 Jan. 19 /Dec. 4
SAN ANTONIO - 111.8 155 IN 2011 Apr. 9 Oct. 12 Feb. 9 /Dec. 25

SUMMARY OF 100 DEGREE INFORMATION…

LOCATION, AVERAGE, 100 RECORD, AVG. FIRST, AVG. LAST, EARLIEST/LATEST DEG. DAYS

AUSTIN MABRY - 12.8 90 IN 2011 Jul. 10 Aug. 20 May 4 /Oct. 2
AUSTIN BERGSTROM - 13.6 74 IN 2011 Jul. 11 Aug. 25 Feb. 21/Sep. 28
DEL RIO - 20.8 85 IN 2011 May 27 Aug. 25 Mar. 16/Oct. 4
SAN ANTONIO – 8.4 59 IN 2009 Jun. 30 Aug. 19 Feb. 21/Sep. 28

RECORD NUMBER OF CONSECUTIVE 100 DEGREE DAYS

AUSTIN MABRY – 27 JULY 17 TO AUGUST 12, 2011
AUSTIN BERGSTROM – 23 JULY 27 TO AUGUST 18, 1951
DEL RIO – 50 JUNE 17 TO AUGUST 5, 1980
SAN ANTONIO – 21 JULY 24 TO AUGUST 13, 1962


First of three “supermoons” this weekend

July 11th, 2014 at 3:19 pm by under Weather

In June of last year, a full Moon made headlines.  The news media called it a “supermoon” because it was 14% bigger and 30% brighter than other full Moons of 2013.   Around the world, people went outside to marvel at its luminosity.

If you thought one supermoon was bright, how about three….? The full Moons of summer 2014—July 12th, August 10th, and Sept. 9th–will all be supermoons.

splash
A new ScienceCast video counts the supermoons of summer 2014. Play it

The scientific term for the phenomenon is “perigee moon.” Full Moons vary in size because of the oval shape of the Moon’s orbit. The Moon follows an elliptical path around Earth with one side (“perigee”) about 50,000 km closer than the other (“apogee”).  Full Moons that occur on the perigee side of the Moon’s orbit seem extra big and bright.

This coincidence happens three times in 2014.  On July 12th and Sept 9th the Moon becomes full on the same day as perigee.  On August 10th it becomes full during the same hour as perigee—arguably making it an extra-super Moon.”

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For the first time, CO2 tops 400 ppm for three straight months

July 11th, 2014 at 2:49 pm by under Weather
Greenhouse gases top 400 ppm for three months in a row at Mauna Loa

(NOAA)  For the first time since carbon dioxide in the atmosphere has been measured, the levels of this greenhouse gas at Mauna Loa, Hawaii, have been above 400 parts per million every single day for three straight months.

“We’ve reached another benchmark, reminding us that carbon dioxide concentrations continue to increase every year as carbon dioxide emissions continue,” said Pieter Tans, who leads NOAA’s measurement program. “Humans have caused carbon dioxide concentrations to rise 120 parts per million since pre-industrial times, with half of that since the early 1980s. Half of all emissions of CO2 from fossil fuel burning have taken place since 1986.”

In 2013, carbon dioxide levels at Mauna Loa, the oldest continuous measurement station operating since the 1950s, reached 400 ppm for several days for the first time during May, but did not stay at this level for an entire month.

Rising greenhouse gases

Rising greenhouse gases

This spring’s readings at Mauna Loa have set a new record for carbon dioxide concentrations in the atmosphere.

This year, the 400 ppm mark was reached two months earlier in March and the average surpassed 400 ppm for the months of April, May and June. You can track greenhouse gas concentrations online at NOAA’s website.

The global average has not yet reached 400 ppm. The global average for May, according to the most recent data, was 398.83 ppm. The average for June is also not expected to reach 400 ppm.

Carbon dioxide concentrations at Mauna Loa begin to decline in June every year as seasonal plant growth drives the uptake of carbon dioxide from the atmosphere. This trend is expected to continue until the end of summer in late September as part of the natural seasonal swing.

Other measurement sites

Arctic sites all reached 400 ppm in May of 2012, about a year before Mauna Loa.  Southern hemispheric sites are expected to follow with the South Pole expected to reach 400 ppm in late 2016.

“To reverse this trend of rising greenhouse gases, nations would need to quickly eliminate about half of fossil fuel emissions globally, and gradually continue further reductions until zero net emissions have been reached,” Tans said.


Why haven’t forecasters declared El Niño conditions?

July 10th, 2014 at 4:40 pm by under Weather

Forecasters at the Climate Prediction Center haven’t declared El Niño conditions, even though the Niño3.4 index is currently around 0.5°C above normal, and has been for the past two months. What’s the hold up? In short, we’re waiting for the atmosphere to respond to the warmer sea-surface temperatures, and give us the “SO” part of ENSO.

SO what? The Southern Oscillation, that’s what. The Southern Oscillation is a seesaw in surface pressure between a large area surrounding Indonesia and another in the central-to-eastern tropical Pacific; it’s the atmospheric half of El Niño. Since ENSO is a coupled system, meaning the atmosphere and ocean influence each other, both need to meet the criteria for El Niño before we declare El Niño conditions.

During average (non-El Niño) times, the waters of the western tropical Pacific are much warmer than in the east/central area (Figure 1). As warmer water extends out to the east during an El Niño, it warms the air, causing it to rise (lower pressure) (Figure 2). In turn, there is less rising motion (higher pressure) near Indonesia, due to the relatively cooler waters and overlying air.

Neutral and El Nino atmospheric conditions

Figure 1. Average state of ocean temperatures, rainfall, pressure, and winds over the Pacific during ENSO-neutral conditions. Figure 2. Generalized state of the ocean and atmosphere during El Niño conditions. NOAA image created by David Stroud.

The pressure changes influence the wind patterns. The average (non-El Niño) state of the atmosphere over the tropical Pacific features convection and rainfall over Indonesia, low-level easterly winds (the trade winds that blow from east to west), and upper-level westerly winds (Figure 1). These are the basic components of the Pacific Walker Circulation.

During El Niño, the system shifts: we see weaker trade winds over the Pacific, less rain than usual over Indonesia, and more rain than usual over the central or eastern Pacific. During some El Niño events, the trade winds along the equator even reverse, and we see low-level westerlies… but not every time. In fact, every El Niño is different, and both the ocean and atmospheric characteristics vary quite a lot from event to event–but that’s a topic for another post!

This difference from average air pressure patterns across the Pacific is measured a few different ways. One is the Southern Oscillation Index (SOI), which is based on a long record of pressure measured by two stations: one in Darwin, Australia (south of Indonesia) and the other in Tahiti (east-central tropical Pacific) (Figure 3). A negative SOI indicates Darwin’s pressure is higher than average and Tahiti’s is lower than average: El Niño conditions. (I keep saying “higher than average” because we’re not just comparing Darwin’s pressure to Tahiti’s, but rather comparing the anomalies at each. Imagine comparing the price of a gallon of water to that of a gallon of gas. A negative index is if the price of the water goes up, and the gas goes on sale. The gas may still cost more than the water, but it’s the relative changes in the two prices that matter.)

A second way we describe the air pressure anomalies over the tropical Pacific is the Equatorial Southern Oscillation Index (EQSOI). The EQSOI is based on pressure differences between two regions located on the equator (Figure 3). The SOI is monitored because it has a very long record available, stretching back to the 19th century; the EQSOI depends on satellite observations, which means it is a shorter record, but it gives a better picture of what’s happening right along the equator.

Southern Oscillation Index

Figure 3. Two ways of measuring the Southern Oscillation: the SOI and the EQSOI. Both depend on comparing the strength of pressure anomalies in different parts of the Pacific basin. Map by NOAA Climate.gov.

As of the end of June, both the SOI and the EQSOI are at +0.2 (they have trended downward over the past few months), and the wind patterns are roughly average over the tropical Pacific, with some slight weakening of the trade winds toward the end of the month. There is increased convection in the central Pacific, but also some over Indonesia… all of which says we’re still waiting for the atmosphere to get dressed in its El Niño clothes and come out to play.

However, we think it’s likely that the atmosphere will get on board soon, and we’re still predicting El Niño, with about a 70% chance that conditions will be met in the next few months, and around an 80% chance by this fall. If you’re interested in how the ocean and atmospheric conditions are evolving, CPC has weekly updates available.

Thanks to David Stroud for his help with this post.


No El Niño yet; the long wait continues

July 10th, 2014 at 3:33 pm by under Weather

(Climate Central)  The months-long wait for El Niño continues: The latest update from the Climate Prediction Center, issued Thursday, finds that conditions still aren’t quite in place to declare a full-blown El Niño, though forecasters still expect one to emerge by the fall. If and when it does, it is expected to impact weather and climate across the world and could push 2014 or 2015 to be the hottest year on record.  Click here to see KXAN First Warning Weather’s special report on how El Niño patterns affect our local weather.

Animation of subsurface temperature anomalies in the tropical Pacific Ocean.
Credit: NOAA.

While the atmospheric characteristics that indicate an El Niño have been evident intermittently, they have yet to firmly take hold. Ocean surface temperatures have also fluctuated, though there is still considerable heat below the surface to fuel an El Niño, said Michelle L’Heureux, a CPC meteorologist who helps put together the monthly outlooks.

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El Niño update Thursday

July 9th, 2014 at 11:04 pm by under Weather

El Nino gif

The Climate Prediction Center will issue it’s monthly El Niño Diagnostic Discussion Thursday morning, and will either leave in place the current La Niña Watch, or issue an El Niño Advisory, meaning the pattern has fully developed. Click here after 8 a.m. Thursday to read the discussion.

Click here to see our First Warning Weather report on the developing El Niño, and how the warm Pacific Ocean pattern has influenced our weather in the past.

ENSO ALERT SYSTEM:

El Niño or La Niña Watch: Issued when conditions are favorable for the development of El Niño or La Niña conditions within the next six months.

El Niño or La Niña Advisory: Issued when El Niño or La Niña conditions are observed and expected to continue.

Final El Niño or La Niña Advisory: Issued after El Niño or La Niña conditions have ended.

NA: ENSO Alert System is not active.

The Climate Prediction Center defines. . .

“El Niño conditions” as existing when:

A one-month positive sea surface temperature anomaly of 0.5C or greater is observed in the Niño-3.4 region of the equatorial Pacific Ocean (5ºN-5ºS, 120ºW-170ºW) and an expectation that the 3-month Oceanic Niño Index (ONI) threshold will be met AND

An atmospheric response typically associated with El Niño is observed over the equatorial Pacific Ocean (see The ENSO Cycle).

“La Niña conditions” as existing when:

A one-month negative sea surface temperature anomaly of -0.5C or less is observed in the Niño-3.4 region of the equatorial Pacific Ocean (5ºN-5ºS, 120ºW-170ºW) and an expectation that the 3-month Oceanic Niño Index (ONI) threshold will be met AND

An atmospheric response typically associated with La Niña is observed over the equatorial Pacific Ocean (see The ENSO Cycle).