Wednesday, June 30, 2010

Satellites Offer Unique Perspective

The image to your left is a visible satellite image of Hurricane Alex, taken early on this Wednesday morning.

The term "visible" comes from the fact that the visible channel senses the solar radiation that is reflected off the surface of the earth. Since the visible channel deals with reflected sunlight, this channel can only be seen during the day. Once the sun goes down, we lose the sunlight, and therefore, the image.

I enjoy looking at the visible satellite, compared to other types of satellites. The reason being is that it shows more features and you can see the different textures when it comes to cloud formations. The bright white clouds in and around Alex show the heavy thunderstorms developing around the center of circulation. If you head east from the center, notice the appearance changes to a milky white. Those are the high, thin cirrus clouds. In this photo, you can also pick out the mid level stratus clouds and even find a few fair weather cumulus clouds as well.

On a daily basis, I look at the visible satellite over the state of Texas. It helps me pick out surface boundaries that might lead to showers and storms. It also better determines how the weather might be changing in the near future.

One of the other forms of satellites we use on a daily basis is the infrared satellite. This is the same shot of Alex, just from a different perspective.

Unlike visible satellite, infrared satellites are good to use 24 hours a day. Infrared satellites measure the temperatures of the cloud tops and emit that temperature source back to outer space.

Typically, the taller the cloud, the colder the cloud tops. Those colder cloud tops show up as the brighter colors in the image above. Notice the dark oranges and red colors located around the center of Alex. That indicates where we have the highest cloud tops and where the showers and storms are strongest.

The first satellite that detected clouds and storm systems came all the way back in 1960. After that, weather forecasting took off, and enabled to us to get a better understanding of how weather works.

Monday, June 28, 2010

Alex Expected to Strengthen, Forecast Path Still Uncertain

Tropical Storm Alex is currently sitting in the southwest Gulf, nearly stationary.

The satellite image shows bright magenta colors starting to fill in around the center of the low. Anytime you see those brightly enhanced colors, that means showers and storms are beginning to develop and that the storm is showing signs of strengthening.

Alex is expected to develop into a hurricane on Tuesday afternoon as it moves over some very deep, warm waters in the Gulf.

The big question remains, where will Alex go from here? The answer is we don't know for sure as there remains a lot of uncertainty as to what the weak steering currents will do.

The latest forecast track from the National Hurricane Center has the storm making landfall anywhere from as far south asTampico, Mexico, to as far north as the lower Texas coast.

It should be noted that earlier today, the forecast track and corresponding computer models wanted to take Alex further north.

However, the latest model runs and forecast track have reverted back to their initial thinking; that is, more of a northern Mexico, extreme South Texas landfall by late Wednesday evening.

The one thing to note is that these forecast tracks will probably shift a few more times, before it really settles in on a certain location.

We will have to watch it closely as the farther north it goes, the stronger the storm will become, and the more impacts we will feel from it.

Tuesday, June 22, 2010

Could Alex Be Near?

For the past week or so, we have been monitoring a tropical wave that has moved westward through the Lesser Antilles. That wave has now combined with another area of disturbed weather and has the potential to develop into our first named storm in the 2010 Atlantic Hurricane season.

I've highlighted the area we are watching, which is situated in the Caribbean Sea, just south of Puerto Rico. The bright colors you see on the satellite image represent the colder cloud tops. Colder cloud tops represent where the heavy rain and thunderstorms are ongoing. As the cloud tops brighten, like in the image above, that usually indicates the system getting better organized.

Right now, upper level winds are too strong to keep this wave from developing an area of low pressure at the surface.

However, the wind shear is expected to decrease as this system moves futher to the west. If that happens, then this system will more than likely develop into a tropical depression or tropical storm. If that's the case, it will be given the name Alex.

Notice that the different computer models take this sytem into the Gulf of Mexico late in the week and into the weekend.
It should be noted that this is "not" a forecast track. Since there is no surface low, this is just a consensus of where it takes this wave or area of disturbed weather over the next 5 days.
If it does make it into the Gulf of Mexico, we will have to watch it closely to see where it heads.
Even if this system does not develop, it could throw some moisture our way and give us some much needed rain next week.
Of course, you can keep up-to-date with any tropical system in the Atlantic or Pacific Basin by going to our Hurricane Center.

Tuesday, June 15, 2010

Tropical Wave Shows Little Sign of Developing

Over the weekend, a tropical wave emerged in the South Central Atlantic, about 2000 miles east of the Lesser Antilles.

This wave has fluctuated from day to day, showing signs of strengthening at one point, only to weaken as the cloud tops warm and the thunderstorms dissipate.

At this point, this tropical wave has a very low chance of developing into a tropical storm, much less a depression.

The main component that will keep this system from gaining strength is the strong wind shear it is encountering.

Those strong upper level winds tear apart storms, and keep them from organizing into a tightly compacted system.

While development is unlikely at this point, we will continue to monitor this wave as well as any other feature in the tropics that could develop.

Make sure you tune in each weeknight to get the latest updates on any activity that may be going on in the tropics.

Of course you can track any storm at anytime this hurricane season by visiting our Hurricane Center.

Thursday, June 10, 2010

Everything from Flooding Rains to Tornadoes

Did you notice all the heavy rain, flash flooding, and isolated tornadoes that occurred on Thursday? Well, if you did not, you did not have far to go to see some incredible rainfall that fell across the Texas Forest Country.

The image to your left is estimated rainfall from Storm Tracker Live Doppler Network.

Notice the swath of heavy rain that fell from Palestine up to Frankston and Tyler. That band of red indicates anywhere from 8-10" of rain that fell from overnight Wednesday and lasting through most of the day on Thursday.

With all of this rain coming down in just a short period of time, there were numerous road closures and high water rescues.

This narrow band of heavy rain was due to a slow moving upper level low which was situated over Anderson county before slowly drifting into Smith county today.

If that low had been further to the southeast, we may have received some of those flooding rains here in Deep East Texas.

In addition to the heavy rain, we even saw a tornado that touched down near 11am Thursday in western Houston county.

This weak tornado touched down just off of Highway 7 on Dickson Hopewell Road. This was about 5-8 miles west of Crockett and southwest of Latexo.

There was a path of downed trees and power lines, but no injuries were reported.

With a tropical airmass in place, it is not uncommon to see a few tornadoes. However, they are typically weak, doing very minor damage.

They are also quick spin ups that are rain-wrapped, so sometimes they are difficult to see.

The National Weather Service out of Houston will survey the damage and rate the tornado over the next couple of days. Odds are it will be an EF0 or an EF1, which is on the low end of the scale.

Monday, June 7, 2010

Record Warmth in the Month of May

If you thought it was unusually hot for May, you would be right. In fact, after crunching the numbers and averaging out the temperatures, this past May was the second warmest May of all time. The average temperature (combining overnight lows and afternoon highs) was 78.3°.

Here is a list of the top 3 warmest Mays on record.

1. May 1996 Avg. Temp. 79.9°

2. May 2010 Avg. Temp. 78.3°

3. May 1998 Avg. Temp. 77.4°

The combination of slim rainfall and dry ground soils allowed temperatures to be much warmer than what we are accustomed to seeing for the month of May.

In addition to the warmth, it was also on of the driest we have seen in quite some time.

In fact, this spring has been the sixth driest spring of all time.

The lack of rainfall and warmer than normal temperatures has put most of East Texas in a "moderate drought" for the time being.

Thankfully June has gotten off to a wetter start. Let's hope it stays that way.