LCRA chief meteorologist Bob Rose writes regularly on weather topics. Do you have a weather question for Bob? Send an email to Bob Rose.
Bob's Video Blog: Yahoo! Rain!
May brought the rain back to Central Texas and not a minute too soon. Lake Travis is expected to rise a couple feet, but don’t think that we’re out of the drought just yet. There’s still a lot of catching up to do.
Bob’s Blog on Central Texas weather
Dry and Warm Weather Pattern Will Persist into Next Week WEDNESDAY, MAY 23, 2012 05:45 PM
I expect few changes in our weather over the next several days as the position of the Jet Stream remains unfavorable to bring storm systems into Texas. Even the threat for significant moisture coming north from the Gulf of Mexico or eastern Pacific Ocean over the coming days appears quite low. The end result will be a partly cloudy, dry and warm weather pattern for at least the next seven days. I will point out that some of today’s long-range forecast data indicates a chance for rain may develop in about another 8 to 9 days when a cold front sinks south into Texas, producing a large complex of rain and thunderstorms.
Atmospheric conditions have been very stable across Texas today, with only scattered fair-weather clouds being reported. I anticipate very similar weather Thursday into Friday with high temperatures in the low 90s. Low temperatures will be mostly in the low 70s. Wind speeds look to increase to around 10-20 mph with gusts to 30 mph beginning Thursday with the breezy pattern lasting through the weekend.
Today’s forecast data continues to indicate a large trough of low pressure over the western US will track northeast from the southern Rockies to the northern Plains states between Sunday and Monday. At the same time, a large ridge of high pressure in the upper atmosphere will take up residence across the southern and southeastern US. The circulation around both features will help pull a bit more moisture into Texas which may result in a few widely scattered afternoon rain showers across Central and South Texas Saturday through Monday. These showers, if they develop, will be very spotty in nature. Most areas will stay partly cloudy and dry. High temperatures Saturday through Monday will be in the low 90s.
The ridge of high pressure over the southeastern US is forecast to weaken early next week. At the same time, another ridge of high pressure is forecast to strengthen over northern and northwestern Mexico. Much of Texas is forecast to be under the influence of a dry and stable west to northwesterly wind flow in the upper atmosphere next week. This will cause partly cloudy and dry weather. High temperatures are forecast to be just a touch lower, generally around 90 degrees.
As I pointed out earlier, there are currently some indications a trough of low pressure moving across the Plains states will push a cold front south into Texas sometime next Friday. An area of rain and thunderstorms is forecast to develop along and behind the cold front Friday into Saturday. But I wouldn’t get too carried away with this threat for rain just yet as this forecast is still very uncertain. I’ll pass along more details in the coming days. This front, should it make it, will only cause very minor changes in the temperature.
Say Hello to Tropical Storm Bud: The tropical depression that was south of Mexico on Tuesday has strengthened into Tropical Storm Bud. Satellite images indicate the system has become better organized with spiral bands beginning to wrap around the circulation center:
Bud was centered late this afternoon about 420 miles southwest of Manzanillo, Mexico, moving to the northwest at about 7 mph. Highest sustained winds are at 65 mph and Bud is forecast to strengthen into a hurricane later tonight or on Thursday. But Bud is forecast to weaken beginning Friday as it moves over cooler water and encounters more wind shear. In fact, the latest forecast data is calling for Bud to dissipate Saturday into Sunday as it approaches the coast of Mexico. Most of the clouds and moisture associated with Bud are forecast to stay over southern Mexico or over the Pacific waters, having little to no effect on Texas weather.
Forecasters at the National Hurricane Center are also monitoring an elongated area of low pressure over the northwestern Caribbean Sea. This low is causing a disorganized area of clouds and rain showers that stretch from Nicaragua, past Cuba to the Bahamas. Upper-level westerly winds are currently too strong for an organized tropical system to develop. However, there is some thought environmental conditions will become more favorable for tropical development in a few days and an organized low pressure may develop somewhere near the west or southern coast of Florida. Steering currents across the eastern Gulf of Mexico are unfavorable for bringing any potential storm to the west. Should anything develop, it would likely track to the north or northeast, affecting Florida or the southeastern US and not the western Gulf.
Bob
Previous Blog Entries
Few Changes Expected in the Weather through the Holiday Weekend. TUESDAY, MAY 22, 2012 06:04 PM [+] Click to view this entry
Unusually quiet weather conditions remain in place across Central and South Texas. Long-term averages indicate late May and early June are typically the wettest period of the entire year. At this time of the year, storm systems often move southeast out of the Plains states and into Texas, producing periods of rain. Also, slow-moving fronts can often make it into the state and be the focus for heavy rain and thunderstorms. But the current Jet Stream pattern isn’t favorable for either of these scenarios to develop. Today’s forecast solutions indicate the Jet Stream will remain well up to the north for at least the next ten-day period, keeping most of the storm systems away from South Texas. The way things stand right now, we may need to be looking out to the Gulf of Mexico for our next significant chance for rain.
Today’s weather maps indicated our region remains under the grips of a broad area of high pressure in the upper atmosphere that is centered over northern Mexico. Upper-level winds across Texas are currently flowing from northwest to southeast. A weak wave of low pressure embedded within this northwesterly flow caused the development of a few thunderstorms across the Panhandle and parts of northwest Texas earlier today. However, these storms dissipated as they tracked southeast into a warmer and more stable atmosphere. Dry and quiet weather will remain in place tonight. Lows Wednesday morning will generally be in the upper 60s.
High pressure in the upper atmosphere looks to remain across Texas and northern Mexico through late week. This feature will cause more sunny and warm weather with daily highs generally in the lower 90s. Breezy conditions will develop Wednesday as surface low pressure begins to strengthen across the central Plains states. A stronger pressure gradient will cause south winds in the range of 10-20 mph. Similar wind speeds will continue on Thursday through Friday.
A large trough of low pressure in the upper atmosphere is forecast to push inland across the western US Friday into Saturday. The trough is forecast to briefly swing south to the Desert Southwest on Sunday before quickly tracking off to the northeast. The approaching trough will cause a large ridge of high pressure to develop across the eastern half of the US beginning this weekend, continuing into early next week. For Central and South Texas, the weather pattern will continue partly cloudy and warm. However, the circulation between the western trough and eastern ridge will pull a bit more tropical air north into Texas. This may result in a few widely scattered afternoon rain showers through the holiday weekend, but I don’t expect any significant rain. High temperatures will be near 90 degrees with low temperatures in the low 70s.
Medium-range forecast solutions indicate a partly cloudy, warm and generally dry weather pattern will be in place across the area next week. The ridge of high pressure over the eastern US is forecast to slowly weaken by late week, eventually being replaced by a weak trough of low pressure. The trough has the potential to cause a slightly more unsettled pattern by late next week. Still, I don’t see any significant rain on the horizon. High temperatures next week will be near 90 degrees with lows in the low 70s.
Update on the Eastern Pacific: The second named storm of the eastern Pacific Hurricane season developed today.
Tropical Storm Bud is currently located about 455 miles south of Manzanillo, Mexico. Highest sustained winds are near 40 mph. According to the National Hurricane Center, conditions are favorable for continued strengthening and Bud could become a hurricane by Thursday. But is forecast to track to the northwest tonight and Wednesday then turn northeast toward the Mexican coast. But today’s data now indicates the center of Bud may never reach the Mexican coast, staying just off shore and weakening over the weekend. There is even some thought the system may turn back to the west and move away from land beginning this weekend. Either way, it now appears unlikely the clouds and moisture associated with Bud will affect South Texas.
By the way, the development of Bud on May 21 marks the earliest date since record keeping began in 1949 for the formation of the season's second named storm. The previous record was set in 1984, when the second named storm formed on May 29. Only two other years have had two named storms in May in the Eastern Pacific--2007 and 1956. In both of these years, the second named storm of the year formed on May 30.
Today’s satellite image also shows a concentrated area of clouds across the Caribbean Sea, to the south of Cuba. This is a disorganized area of low pressure which could possibly generate into a tropical or subtropical system over the next few days. This system, should it develop, will likely track to the north-northeast and not towards Texas.
FANTASTIC ECLIPSE: I had to show one more spectacular picture from Sunday’s solar eclipse. This picture was taken from the west Texas town of Gail, by Jacob Thumberger.
Many more pictures of the eclipse may be found in the new realtime photo gallery from NASA’s Spaceweather.com, http://www.spaceweather.com
Bob
Summer Weather Pattern Beginning to Settle In For an Extended Stay MONDAY, MAY 21, 2012 06:08 PM [+] Click to view this entry
A quiet and dry weather pattern will remain in place across the region this week as the storm track remains up to the north of Texas. It’s going to feel a lot like summer with daily high temperatures near 90-92 degrees and low temperatures around 68 to 70 degrees. While an isolated Sea Breeze shower might be possible along the coast, most locations will likely stay dry through the end of the week. This weekend and early next week, there will be a very slight chance for a few scattered rain showers and tropical moisture increases off the Gulf of Mexico. At the same time, some moisture associated with a land falling eastern Pacific hurricane may spread north into South Texas, also leading to a few scattered showers. But overall, the Memorial Day weekend is shaping up partly cloudy and warm.
Today’s upper-air analysis across North America showed a ridge of high pressure across the western US and a closed area of low pressure across the Mid-Atlantic States. Between these two features, a trough of low pressure was tracking east across the Plains states.
A cold front associated with the trough of low pressure pushed south into North Texas on Sunday. This afternoon, the front had pulled up stationary near Interstate 20. Earlier today, some clusters of thunderstorms developed behind the cold front along the Red River that tracked southeast. The storms dissipated by afternoon as they moved into a more stable atmosphere. There will be a very slight chance that a few thunderstorms could still develop across the northern counties of the Hill Country and Central Texas region late this afternoon and evening but the chance for storm development will be less than 20 percent. Any potential storms will be facing a warm and fairly stable environment. Otherwise, tonight’s weather will feature a partly cloudy sky. Lows Tuesday morning will be mostly in the mid and upper 60s.
Weather conditions Tuesday through Friday will be mostly sunny, warm and very summer-like. High pressure in the upper atmosphere over the western US will slowly shift to the eastern US by late week. The atmosphere across South Texas during this period will remain warm and stable, so I don’t expect any rain other than a stray Sea Breeze shower or two near the coast. Breezy conditions will be in place throughout the week, with wind speeds generally in the range of 10-20 mph. Daily high temperatures will be near 90-92 degrees. Low temperatures will be near 70 degrees. Welcome to summer!
Beginning this weekend, a large trough of low pressure in the upper atmosphere will develop across the western US. At the same time, a large ridge of high pressure will be in place across the western US. The trough is forecast to swing south the Four Corners region Sunday then rapidly lift north-northeast across the Plains states on Monday. The circulation between the western trough and eastern ridge will help pull a bit more tropical moisture north into Texas off the Gulf of Mexico. This will result in a partly cloudy sky and a few widely scattered afternoon rain showers Saturday through Monday. Overall, the weather will be partly cloudy and warm with the chance for rain around 20 percent or less. Afternoon high temperatures will generally be near 88-90 degrees with lows in the low 70s.
Another feature that might possibly bring a few showers to South Texas is a tropical weather system in the eastern Pacific. An afternoon visible satellite image shows a large area of clouds located about 510 miles south of Acapulco, Mexico:
This is tropical depression 2-E with maximum sustained winds at 35 mph. The depression is currently moving to the west-northwest at 6 mph. The depression is in an environment that is favorable for tropical development and the system may become a tropical storm later tonight. In fact, the system may even strengthen into a hurricane by late Tuesday or Wednesday. Forecasters at the Hurricane Center indicate the system will track northwest over the next 2 to 3 days but then turn more to the north as the trough of low pressure across western US begins to pull it north. The latest Hurricane Center forecast calls for the tropical system to approach the coast of Mexico by Saturday but it’s unclear whether the system will actually get pulled inland. Some of today’s forecast solutions indicate as the western trough moves north to the Plains, the tropical system will get left behind along the Mexican coast and the system will end up moving back out to sea. This system has the potential to push some tropical moisture into Texas over the weekend, but this scenario is very iffy at the current time.
Today’s satellite image also shows Tropical Storm Alberto, located off the coast of Georgia and South Carolina. This is the first tropical cyclone of the 2012 Atlantic Hurricane Season. Highest sustained winds are near 40 mph. Alberto is a rather compact little system with a minimal amount of clouds and storms. Alberto is currently in an environment that is not favorable for strengthening and may lose its tropical characteristics by Wednesday. The system is forecast to turn northeast and accelerate in speed away from land over the next couple of days.
Today’s forecast data indicates generally dry and summer-like weather will continue across our region next week. The Jet Stream is forecast to lift further north toward the Canadian border as a broad ridge of high pressure sets up across Texas. I expect the weather to be partly cloudy and warm with high temperatures generally around 90 degrees. So far, I don’t see any significant rain in our forecast over the next 10 days.
FANTASTIC ECLIPSE: The Moon passed in front of the sun on Sunday, May 20th, producing a deep solar eclipse visible across the western US and the Pacific side of Earth. Sunlight dimmed, the air cooled, ordinary sunbeams turned into fat crescents and rings of light. No matter where you were, the eclipsed sun was breath-taking.
The following image was taken in Roswell, New Mexico by Michael Ward. This was the true “ring of fire”, where the moon covered up most of the sun. It was an amazing site!
In Central and South Texas, the eclipse was only partial but was still quite amazing. I took the following picture from Mount Bonnell in Austin just before sunset:
Next up on the “must see” astronomy schedule is the transit of the planet Venus across the sun on June 5th. You can read more details about this event in the following story from NASA:
May Weather Turns Quiet; Dry and Warm Weather Expected through Late Next Week. FRIDAY, MAY 18, 2012 05:11 PM [+] Click to view this entry
The first two weeks of May featured a very active weather pattern across Central and South Texas. But this active pattern abruptly changed this week when the Jet Stream shifted away from Texas. Storm systems moving inland along the West Coast are now turning northeast across the Plains states instead of sinking southeast across northern Mexico and Texas. As a result, our weather has become sunny, dry and warm. In fact, it’s beginning to feel a lot like early summer. Today’s forecast data indicates the current dry and warm weather pattern will likely continue at least through late next week, and possibly much longer. Slightly warmer temperatures are forecast next week.
An afternoon visible satellite image sums up nicely the very quiet weather conditions currently in place across the south central US, northern Mexico and the western Gulf of Mexico.
You may notice there is an enhanced area of clouds located over the western Caribbean Sea between the Yucatan Peninsula and Cuba. While these clouds look somewhat suspicious, they’re associated with low pressure in the upper atmosphere and not a developing low at the surface. Upper-level westerly winds are currently too strong for tropical development. Clouds and showers associated with the upper low are forecast to move northeast towards Florida, staying far away from Texas.
Atmospheric conditions across Central and South Texas will remain relatively dry and stable this weekend, so no rain is forecast. The sky will be mostly sunny both days with high temperatures both days near 88-90 degrees. Breezy south winds of 10-20 mph are forecast Saturday but wind speeds should relax to around 5 to 12 mph on Sunday. A weak Pacific cold front will push into the Texas Panhandle Sunday and settle just south of the Red River on Monday. There appears to be little support to drive the front any further south. A few scattered thunderstorms will be possible across parts of northwest Texas Sunday afternoon and Far North Texas Monday afternoon. But all of this potential activity looks to stay well north of the Hill Country and Central Texas.
Next week, a ridge of high pressure is forecast to grow stronger across Texas and northern Mexico. The ridge will cause continued dry, stable and warm weather. Breezy conditions look to develop Wednesday and continue through late week. High temperatures Monday and Tuesday will be near 88-90 degrees, rising to around 90-92 degrees Wednesday through Friday. Low temperatures next week will generally be in the upper 60s.
The ridge of high pressure over Texas is forecast to shift east late next week as a deep trough of low pressure develops across the western US. This pattern can be seen in the following upper-air forecast for next Saturday, May 26th, from the European Center for Medium-Range Weather Forecasting:
Note the center of the ridge is over the Ohio Valley while the trough is centered near the West Coast. A pattern such as this typically brings very moist air inland across much of Texas. The increasing moisture should lead to a few more clouds and possibly some scattered rain showers. The European model is hinting at some possible showers for next weekend. But overall, the partly cloudy and warm weather should continue. I’ll have more details on the Memorial Day weekend weather in Monday’s report.
ANNULAR SOLAR ECLIPSE: On Sunday, May 20th, the Moon will pass in front of the Sun, producing a "ring of fire" solar eclipse visible across the Pacific side of Earth from China to the United States. Unfortunately, this “ring of fire” won’t be visible across Central and South Texas. You will have to travel to West Texas, between Midland and Lubbock to see that. However, a partial solar eclipse, where the sun takes on a crescent shape, will be visible locally just before sunset. A little more than half of the sun will disappear behind the moon just before the sun sets below the horizon. The eclipse will begin around 7:30 pm CDT. Be watching between 7:30 pm and sunset. In Austin, sunset on Sunday will be at 8:21 pm. The sun will set a little earlier for areas east of Austin and a little later for areas to the west.
Because this is not a total eclipse, some portion of the sun will always be exposed. To prevent eye damage, use eclipse glasses, a safely-filtered telescope, or a solar projector to observe the eclipse. You can make a handy solar projector by criss-crossing your fingers waffle-style. Rays of light beaming through the gaps will have the same shape as the eclipsed sun. Or look on the ground beneath leafy trees for crescent-shaped sunbeams and rings of light.
The sky should be mostly clear Sunday evening across Central Texas so conditions should be nearly ideal for viewing.
Have a good weekend.
Bob
An Early Summer Pattern Will Persist. Looking at the Latest Drought Monitor and Outlook. THURSDAY, MAY 17, 2012 06:12 PM [+] Click to view this entry
The weather looks to stay dry and quiet for the next several days as the storm track stays north of Texas. An area of high pressure in the upper atmosphere will be in place over Texas through the period, causing generally dry and stable atmospheric conditions. In general, an early summer weather pattern appears to be settling for at least the next week to ten day period.
Today’s weather indicates a bubble of mild, Canadian high pressure continues to cover most of Texas and the western Gulf of Mexico. The high pressure system was centered just off the middle Texas coast. A clockwise wind flow around the high has caused the development of light southerly winds. So far, the air mass across Texas remains fairly dry with surface dewpoint temperatures still in the 50s. However, moisture levels will begin increasing on Friday. In the meantime, tonight’s sky will stay clear and lows Friday morning will generally be in the low 60s.
Friday’s weather will again be sunny and warm. But falling surface pressure across the eastern Rockies and central Plains states will cause wind speeds to increase across much of Texas. Locally, expect wind speeds in the range of 10-20 mph beginning Friday and continuing through Saturday night. Friday’s temperature will rise to the upper 80s while lows Saturday morning will be in the mid 60s. Weather conditions will continue mostly sunny and warm Saturday through Sunday with highs both days near 90 degrees.
In Wednesday’s report, I talked about a weak cold front that is forecast to sag into northwest Texas on Sunday. Today’s forecast data is again indicating the front will push into northwest Texas on Sunday but pull up stationary just north of San Angelo late Sunday into Monday. A few rain showers may develop near the cold front on Sunday but this activity looks to stay well north of the Hill Country and Central Texas regions.
Medium-range forecast data indicates a weak ridge of high pressure will remain across Texas through late next week causing more sunny, dry and warm weather. The storm track is forecast to lie well north of Texas. Expect daily high temperatures near 90 degrees and low temperatures near 70-72 degrees.
Most all of today’s medium-range solutions indicate dry and warm weather conditions will continue through the Memorial Day weekend. The weather is expected to stay very summer-like. It is interesting to note that today’s European model is calling for a large area of tropical moisture to spread into Texas off the Gulf of Mexico late next week, causing a widespread area of rain. As of now, this solution is a wet outlier but not totally out of the question. I’ll continue to monitor and pass along additional updates.
Widespread Clouds Over the Southeastern Gulf of Mexico: Visible satellite images show widespread clouds over the southeastern Gulf of Mexico and the western Caribbean Sea:
These clouds are primarily associated with the same trough of low pressure in the upper atmosphere which brought rain to Texas a couple of days ago. Surface pressures are not falling significantly and atmospheric conditions are not very favorable for tropical development. This “blob” of clouds and moisture is forecast to move northeast across Cuba and southern Florida over the next few days. Upper-level winds won’t allow the moisture to come towards the Texas coast at the current time.
Updated Drought Monitor: Today, the National Weather Service and its partners released their weekly Drought Monitor for Texas. The monitor shows drought conditions continue to improve in most areas due to the recent rains:
In this week’s monitor, only 1 percent of the state was shown to be in exceptional drought. At the height of the drought last fall, 88 percent of the state was designated as being in exceptional drought. This is the lowest percentage of exceptional drought across Texas since March 29, 2011. Extreme drought has decreased to 14 percent of the state and severe drought now covers just 34 percent. This is really good news!
Across the Hill Country, an area moderate to severe drought stretches from west of Austin to the Rio Grande River. Elsewhere, just “abnormally dry” conditions are indicated. The region is still dealing with long-term rainfall deficits and low water supplies. But the overall drought situation has definitely improved from last fall.
New Drought Outlook: The National Weather Service also issued an updated 3-month drought outlook earlier today:
The outlook, covering the period from May 17 through August 31 indicates drought conditions will persist across parts of the Hill Country. Elsewhere, the outlook does not indicate a trend toward drought over the next 3 months. The drought monitor author indicated there are currently no clear trends for above, below or normal rainfall over the next 3 months, so persistence is forecast. This summer outlook is very different from what we were looking at a year ago.
