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Bob's LCRA Video Blog: What's bringing all these cool temperatures to Texas?
LCRA Meteorologist Bob Rose talks about why our spring temperatures have been below normal and what that could mean mean for summer temperatures and rainfall.
Bob’s Blog on Central Texas weather
Strong to Severe Thunderstorms Possible This Afternoon and Evening. TUESDAY, MAY 21, 2013 11:20 AM
…Strong to severe thunderstorms are forecast to develop across the eastern Hill Country and most of Central Texas beginning around mid afternoon, continuing into tonight. Large hail, damaging winds and isolated tornadoes will be possible with these storms...
A strong disturbance in the upper atmosphere tracking southeast out of southern New Mexico is forecast to track across North Texas this afternoon and tonight. This disturbance will help push a cold front southeast out of North Texas. As of mid-morning, the cold front stretched from Wichita Falls to Sweetwater to near Midland. The front is forecast to reach the northern Hill Country in the mid to late afternoon and the Austin/I-35 corridor area this evening. The front will serve as a focus for thunderstorm development. Forecasters will also be monitoring the eastward progress off the Dry Line out of West Texas. The Dry Line will serve as another focus for thunderstorm development. This morning’s atmospheric analysis indicates the atmosphere over the eastern Hill Country and Central Texas is potentially very unstable. A cap, or stable layer in the middle atmosphere is currently in place, limiting the development of thunderstorms. However, as the temperature warms this afternoon, the cap is forecast to weaken, allowing thunderstorms to develop primarily along the 2 boundaries, with the storms moving generally to the east and southeast.
The Storm Prediction Center has placed much of the Hill Country and all of Central Texas under a Slight Risk for severe thunderstorms this afternoon and tonight (yellow shaded area). Note; a moderate risk for severe thunderstorms (red shading) covers the area from just north of Austin across northeast Texas into southern Arkansas.
Thunderstorms are forecast to develop across the Hill Country along the two boundaries around mid afternoon with the storms tracking east into Central Texas late this afternoon and evening. Very large hail, damaging downburst winds and dangerous lightning will be the primary severe weather threats. However, isolated tornadoes will be possible. The most favorable area for tornado development is expected to be in the moderate risk area, across parts of North and Northeast Texas. The thunderstorms are forecast to continue into tonight then weaken by midnight as they sink to the east and southeast. Totals from today’s storms are forecast to average around a half inch with isolated totals of 1-2 inches possible.
On Wednesday, the focus for rain and thunderstorms will shift to the coastal plains region as today’s cold front pulls up stationary near Interstate 10. Today’s forecast data indicates the storms on Wednesday’s will generally stay below the severe threshold. Totals to near a half inch are forecast. Across the Hill Country and Central Texas, sunny and dry weather is forecast, with high temperatures near 90 degrees. Dry and sunny weather looks to continue through the Memorial Day weekend.
I urge everyone to keep up with weather developments this afternoon and evening. Listen to NOAA All-Hazards radio or your local news media outlet for the latest watches and warnings. I plan to send out another update around mid afternoon.
Bob
Previous Blog Entries
A Chance for Strong to Severe Storms Tuesday. Dry and Warm Late Week. MONDAY, MAY 20, 2013 06:43 PM [+] Click to view this entry
A very active pattern of weather continues across the southern Plains states. Over the past 3 days, nearly 50 tornadoes have occurred across this region and more severe storms and tornadoes are expected on Tuesday. Today’s analysis of the upper atmosphere shows a very interesting weather setup:
A large area of low pressure is in place across the northern and central Plains states. Circulation around the low is bringing cooler, drier air south out of Canada. Meanwhile, a broad ridge of high pressure is in place over the southeastern US and the Gulf of Mexico. Circulation around the ridge is pulling warm and very moist air north from the Gulf of Mexico. The circulation from both of these systems is converging from northern Texas to the Corn Belt. A strong Jet Stream can be seen in the wind barbs, stretching from southern New Mexico to the western Great Lakes. This strong Jet has enhanced thunderstorm development by providing a very efficient exhaust to thunderstorm updrafts. The clash of air masses, very warm and moist conditions at the surface and a strong Jet Stream are all contributing to this very active pattern. Unfortunately, these same conditions are forecast to be in place again on Tuesday but the activity may develop further south into the Hill Country and Central Texas regions as a weak cold front sinks south out of northwest Texas.
This evening, there will be a slight chance for thunderstorm development across the Hill Country. Thunderstorms may develop along the Dry Line across the western Hill Country and track to the east. However, a stout stable layer in the middle atmosphere is present across most of the Hill Country and Central Texas, so the chance for thunderstorm will be slight. Should a thunderstorm happen to develop, it would likely become severe, producing very large hail and damaging winds. The threat for thunderstorm development will decrease in the late evening as temperatures cool. Across the rest of the region, the weather should be quiet overnight. Low temperatures Tuesday morning will be in the low 70s.
A more widespread threat for rain showers and thunderstorms is forecast across the region Tuesday afternoon into Tuesday night when a trough of low pressure in the upper atmosphere tracks southeast out of southern New Mexico and moves east across North Texas. With a stationary cold front in place across North Central Texas and a Dry Line stretching to the south across the Concho Valley, atmospheric conditions will be favorable thunderstorms to develop along these two boundaries in the afternoon, moving to the east-southeast. The atmosphere over the Hill Country and Central Texas is forecast to grow increasingly unstable in the mid to late afternoon hours so developing thunderstorms will have a strong potential to become severe. The Storm Prediction Center has placed all of the Hill Country and all of Central Texas under a Slight Risk for severe thunderstorms Tuesday afternoon into Tuesday night:
Severe weather outlook for Tuesday and Tuesday night:
Yellow area notes the Slight risk area for severe thunderstorms while the green area notes the area of general, non-severe thunderstorms.
The primary severe weather threats will be very large hail and damaging downburst winds but isolated tornadoes cannot be ruled out. The area of thunderstorms is forecast to track southeast Tuesday evening into Tuesday night; slowly weakening after dark. Most of this activity is forecast to diminish before it reaches the middle Texas coast. Rain amounts from Tuesday’s storms are forecast to average around a half inch with isolated totals of 1-1.5 inches possible.
Today’s forecast data indicates there will be a very slight chance for thunderstorms across the coastal plains region Wednesday afternoon. Across the rest of the area, partly cloudy and dry weather is expected. Wednesday’s high temperature will generally be around 90-92 degrees. A building ridge of high pressure in the upper atmosphere over Texas and the south central US late week and into the upcoming weekend will cause a mostly sunny, dry and warm weather pattern. Daily high temperatures look to be in the low 90s with low temperatures around 70 degrees. Today’s long-range forecast data indicates this dry and warm pattern will continue on Memorial Day and through the first half of next week. High temperatures will be in the low and middle 90s.
Bob
Summer Weather Has Arrived Early and Looks to Stick Around For Quite a While. FRIDAY, MAY 17, 2013 06:15 PM [+] Click to view this entry
It would appear that over the past couple of days our weather pattern has quickly transitioned to summer. Thursday and again today, the temperature soared into the low and middle 90s across much of Central Texas while triple-digit temperatures were observed across the western Hill Country. Temperatures early this morning only dipped to the low and middle 70s. The combination of very warm temperatures and high relative humidity levels are certainly making it feel like the middle of summer. Unfortunately, this warm and sticky pattern looks like it’s going to be with us for some time now as the positions of the position of the Jet Stream is no longer allowing cool Canadian air to reach south into Texas. In fact, long-range forecast data indicates summer-like temperatures will likely continue across the region through the end of the month.
By the way, you may have noticed quite a bit of haze across the sky today. This haze is actually smoke from agricultural fires in Central America that is being pulled north into Texas by gusty south winds. Today’s polar orbiting satellite image covering the eastern half of Texas and the western Gulf of Mexico from the Aqua satellite showed this “haze” quite well:
Today’s analysis of the upper atmosphere across North America showed a broad ridge of high pressure covering the southern Gulf of Mexico and southern Mexico, extending north to the southern Plains states. This feature, combined with a bubble of hot air spreading into Texas out of Mexico is responsible for the recent spell of unseasonably hot temperatures:
Note how the Jet Stream is generally flowing from California to southern Canada and south into the northeastern US. With this type of configuration, the cooler air is now well to the north of Texas.
Late this afternoon, a cluster of thunderstorms developed across the northern Hill Country between Junction and San Saba. These storms developed along the Dry Line, in a small zone where a mid-level stable layer weakened enough to allow thunderstorms to develop. 100-degree temperatures across West Texas also aided in making the atmosphere more e unstable. This area of storms will continue into the evening hours and diminish after sunset. Across the rest of the region, a broad layer of warm air in the middle atmosphere will limit thunderstorm development. The sky will become cloudy overnight and low temperatures Saturday morning will again be mostly in the low 70s. A south wind of 10-15 mph will continue overnight.
A very similar weather setup is forecast Saturday. Overall, weather conditions will be mostly sunny, breezy and warm. High temperatures will range from the upper 90s across the western Hill Country to near 90 degrees towards the coast. Expect a south winds at 10-20 mph. There will again be a slight chance for some late afternoon thunderstorms across the northern and western Hill Country as the Dry Line pushes east out of West Texas. Should storms develop, they’ll have a strong potential to become severe. The chance for rain will be at 20 percent. These potential storms could possibly move as far east as the Interstate 35 corridor before diminishing in the late evening.
That small chance for thunderstorms is forecast to decrease on Sunday with the Dry Line holding across Far West Texas. Expect another sunny and breezy day with high temperatures ranging from the upper 90s out west to near 90 degrees towards the coast. Very similar weather and temperatures should continue into Monday.
Some slight changes in the pattern look to occur Tuesday afternoon into Wednesday when a weak cold front sags south out of North Texas and pulls up stationary somewhere over Central Texas. There will be a slight chance for scattered rain showers and thunderstorms between Tuesday afternoon and Wednesday evening across the entire region. Wednesday’s sky will likely stay mostly cloudy on Wednesday. High temperatures both days will be near 88-90 degrees. Rain amounts between late Tuesday and late Wednesday are not expected to be very heavy with most totals averaging between a quarter and a third of an inch.
Late next week into next weekend, high pressure in the upper atmosphere is forecast to re-strengthen across Texas. Dry and hot weather is forecast with high temperatures in the 90s and lows in the 70s. Unfortunately, today’s forecast data doesn’t call for any significant rain across Central Texas through the end of the month.
Have a good weekend and stay cool.
Bob
A Suumer-Like Weather Pattern Will Continue into Next Week. THURSDAY, MAY 16, 2013 06:41 PM [+] Click to view this entry
Summer-like heat set up quickly across Central and South Texas as a bubble of hot air spread northeast out of Mexico. Southwesterly breezes in the wake of Wednesday’s large area of low pressure help pull this hot air northeast. With a strong sun and relatively dry soils, temperatures heated up quickly. For many locations, Thursday temperature was the hottest so far this year. A check of LCRA’s Hydromet showed readings reached or exceeded 100 degrees across the western Hill Country, reaching the low and middle 90s across much of the rest of the Hill Country:
Max Temperatures Thursday:
In Austin, the temperature peaked at 93 degrees at Camp Mabry and at 91 degrees at Austin-Bergstrom International Airport. Interestingly, the temperature only reached the low and middle 80s across the coastal plains region. These relatively “cooler temperatures” are generally the result of cool sea surface temperatures in the low and middle 70s across the western Gulf of Mexico and a few more clouds compared to inland locations.
A ridge of high pressure in the upper atmosphere located over northern Mexico and the southwestern US will spread east across Texas on Friday, causing a sunny, dry and hot weather pattern. High temperatures will be near 100 degrees across the western Hill Country, in the mid and upper 90s across the rest of the Hill Country, the low and middle 90s across Central Texas and the upper 80s across the coastal plains. Breezy south winds of 10-20 mph will be in place.
Only minor changes in the “summer-like” pattern are expected this weekend and Monday . The large ridge of high pressure is forecast to move east of Texas on Sunday as a large trough of low pressure develops over the southern Rockies and the southwestern US. A few isolated thunderstorms will be possible across the western Hill Country Saturday and Sunday afternoons as the Dry Line pushes east from the Rio Grande Plains. No significant rain is forecast. A mostly sunny and warm pattern will continue. Daily high temperatures will range from the mid 90s across the western Hill Country to the low 90s across Central Texas to around 90 degrees near the coast. Low temperatures will be in the low 70s.
The trough of low pressure over the southern Rockies is forecast to lift northeast to the Plains states on Tuesday, dragging a weak cold front into Texas. Today’s forecast data indicates the front will be weaker than forecast Wednesday. It should sag south toward Central Texas late Tuesday and pull up stationary. The front will cause a slight chance for thunderstorms across the Hill Country and Central Texas regions late Tuesday into Tuesday night. Actual rain totals will be low. A weak ridge of high pressure is forecast to build across Texas next Wednesday through Friday, causing more dry and warm weather. High temperatures will remain near 90 degrees. Long-range forecast solutions continue to call for a mostly dry and warm pattern lasting through the end of the month.
National Weather Service Summer Forecast: Today, the National Weather Service issued its monthly seasonal outlook of temperature and precipitation. Unfortunately, the outlook is not all very promising for wet weather. For the months of June-July and August, the outlook calls for above normal temperatures and equal chances for above, below or near normal rainfall:
Temperature Precipitation
Climate Prediction Center forecasters indicated there was little trend for precipitation across Texas this summer. Dry soils across the region will likely play a role in warmer than normal temperatures and near to below normal rainfall. Of course, tropical weather could change things significantly.
Bob
Say Hello to 90-Degree Temperatures. Little to No Rain Expected through Next Week. WEDNESDAY, MAY 15, 2013 06:44 PM [+] Click to view this entry
After an unusually cool start to the month of May, our weather pattern is now transitioning to a warm, more spring-like pattern that is typical of late May. Over the next few days, a ridge of high pressure in the upper atmosphere will strengthen over Texas as the Jet Stream shifts north towards the Canadian border. This ridge will cause generally stable weather and somewhat noticeably warmer temperatures. I expect a fairly widespread coverage of 90-degree temperatures across most of Central Texas and the Hill Country with middle and upper 90s across the western and northern Hill Country. A weak cold front looks to bring some slightly cooler temperatures for the middle of next week with more 90-degree heat returning late week. Let’s face it; it’s the middle of May in Central Texas and summer is just around the corner. There will be very few cool mornings in the weeks ahead.
Some spring-like thunderstorms will be possible across parts of the Hill Country and Central Texas this evening as a wave of low pressure swings southeast out of New Mexico and Far West Texas. This wave of low pressure is circulating around a broad area of low pressure in the upper atmosphere that lifted northeast out of Mexico early this morning. As of low Wednesday afternoon, the low was centered over central Oklahoma, moving to the northeast. An afternoon visible satellite image shows the swirl of clouds associated with low very nicely:
Thunderstorm clouds can be seen developing across northwest Texas and these are moving to the southeast. As of late this afternoon, the atmosphere over the Hill Country and Central Texas was slightly unstable and it’s possible these thunderstorms could build south across the region through the evening hours. Some of these storms may be severe, possibly producing large hail and damaging winds. The Storm Prediction Center has placed all of the Hill Country and the Interstate 35 corridor extending south to San Antonio under a Slight Risk for severe thunderstorms overnight. Potential rain amounts will average around a half inch with isolated heavier totals. The chance for rain tonight will range from 50 percent across the western Hill Country to the 30 percent across Central Texas to 20 percent towards the coast. This potential thunderstorm activity should diminish late tonight as the temperature cools. Lows Thursday morning will generally be in the upper 60s.
A mostly sunny to partly cloudy sky will develop Thursday as the upper low exits to the middle Mississippi Valley and a ridge of high pressure begins to strengthen over Texas out of Mexico. Thursday’s temperature looks to warm to the upper 80s at most locations with some low 90s across the western and northern Country. This ridge of high pressure is forecast to hold in place across Texas Friday through Sunday, causing a warm, summer-like temperature pattern. Daily high temperatures will be near 90 degrees across Central Texas and the coastal plains region. Across the Hill Country, highs will be in the low 90s with some middle and upper 90s occurring across the western and northern Hill Country. Some thunderstorms may develop across parts of the Hill Country Sunday afternoon and Sunday evening when a disturbance moving out of the southern Rockies pushes the Dry Line east out of West Texas. While conditions are not expected to be all that favorable, some thunderstorms may develop.
Partly cloudy, warm and breezy weather is forecast Monday as a strong trough of low pressure in the upper atmosphere pushes east out of the Rockies. Expect south winds of 15-25 mph. High temperatures will be mostly in the low 90s with mid and upper 90s across the western Hill Country.
That trough of low pressure moving across the Plains states is forecast to push a weak cold front into Texas next Tuesday. The front is forecast to push south into Central Texas late Tuesday and push off the coast Tuesday night. The front may cause a few rain showers and thunderstorms but the atmosphere is shaping up to be fairly warm and stable. As of now, rain totals are only forecast to be around a quarter inch. Dry and slightly cooler air is expected to follow the cold front Wednesday through Friday as a weak bubble of Canadian high pressure builds south into Texas. High temperatures will be mostly in the low and middle 80s with lows in the 60s. Dry and warmer weather looks to return late next week into next weekend. Unfortunately, today’s long-range data is not calling for any significant rainfall developing over the next couple of weeks.
Eastern Pacific Tropical Weather Season Opens with a Bang: Today marks the official start to the 2013 Eastern Pacific Tropical weather season. And coincidentally, the first tropical storm of the season developed earlier today. Tropical Storm Alvin was centered late this afternoon about 665 miles south-southwest of Acapulco, Mexico, moving to the west-northwest at 13 mph. It shows up nicely as that large swirl of clouds south of Mexico:
Maximum sustained winds are near 40 mph and additional strengthening is forecast. Alvin could become a hurricane in a couple of days. Alvin is forecast to move to the west-northwest over the next few days, having no effect on any land areas. The development of a tropical storm on the first day of hurricane season might indicate this could be an active season for the eastern Pacific basin. By the way, the Atlantic hurricane season officially begins June 1st.
