LCRA Chief Meteorologist Bob Rose on spring, rain and the persistent drought

The Texas Hill Country has been unusually dry since the first of the year, with some areas only receiving a half inch of rain. Bob Rose, chief meteorologist for the Lower Colorado River Authority, looks at what's in store for May and June, historically two of the wettest months for the region.

 

 

Bob's Blog on Central Texas Weather

Warm Temperatures through the Week with Just a Couple of Chances for Rain.
Tuesday, April 22, 2014 5:54 PM

Our weather looks to stay generally dry and warm for the remainder of the week and into the weekend.  There will be a slight chance for a few scattered thunderstorms late Wednesday into Thursday and again on Sunday but no significant rain is expected.  The temperature is expected to be quite warm over the next few days.  In fact, readings may warm above 90 degrees over much of the area this weekend and Monday before cooler air arrives Monday night.  This cold front will be an unusually strong front for late April and looks to bring unseasonably cool air to much of Texas next week.

A weak Pacific cold front pushed south across the region late Tuesday night into Wednesday morning, bringing drier air and causing northeasterly winds.  As of late Tuesday afternoon, the front was stationary along the middle and upper Texas coast, extending west to near Del Rio.  South of the cold front, readings warmed in the low 90s Tuesday afternoon across a large part of South Texas.  North of the boundary, temperatures reached the low and middle 80s.  The cold front is forecast to remain stationary Tuesday night then lift back to the north as a warm front on Wednesday.  Low temperatures Wednesday morning will be in the upper 50s across the Hill Country and in the low 60s at most other locations.

Southerly winds with speeds of 10-15 mph will return to the region Wednesday morning as the warm front moves back to the north.  Wednesday's weather will feature a mostly sunny sky with warm temperatures.  High temperatures will be in the upper 80s to 90 degrees across the Hill Country and in the middle to upper 80 at most other locations.

Forecasters will be monitoring weather developments across the Texas Panhandle and Northwest Texas Wednesday afternoon and Wednesday evening where the West Texas Dry Line is forecast to become active.  A trough of low pressure tracking northeast out of the Desert Southwest is forecast to cause the development of scattered thunderstorms along the Dry Line across the Texas Panhandle Wednesday afternoon.  Upper-level winds look to steer any potential thunderstorms to the northeast.  For the most part, all of this activity should stay to the north of the Hill Country and Central Texas.  However, should storms happen to develop further south into the Pecos or Concho Valleys, there's an outside chance a couple of these storms could track east across the northern Hill Country Wednesday evening.  The chance for rain here will only be 20 percent.

There will be a slight chance for thunderstorms across the Hill Country and the Interstate 35 corridor regions Thursday afternoon when a Pacific cold front associated with the upper trough pushes east out of West Texas.  Although atmospheric conditions are not expected to be all that favorable, it's possible a few scattered thunderstorms may develop along the boundary when it pushes east out of West Texas.   Based on today's data, the chance for rain will be 20 percent at best across the Hill Country and Central Texas on Thursday.  Aside from this very slight chance for rain, Thursday's weather should be partly cloudy and warm with high temperatures in the mid and upper 80s.  The low temperature Friday morning will be in the mid 60s.

Partly cloudy, dry and stable weather is forecast Friday through Saturday as a weak ridge of high pressure sets up over Texas.  Very warm temperatures are forecast both days.  High temperatures look to be in the upper 80s Friday and near 90-92 degrees on Saturday.

Another slight chance for thunderstorms is forecast Sunday when yet another trough of low pressure tracks northeast out of the southwestern US, dragging a cold front into Texas.  Forecast solutions call for just a slight chance for thunderstorms along the cold front when it moves across Central and South Texas.  Unfortunately, atmospheric conditions aren't forecast to be very favorable for the development of rain when the front pushes into the area.  Today's data suggests the chance for rain will be 20 percent at best.  Sunday's weather will be partly cloudy and quite warm with high temperatures again near 90-92 degrees.

Looking ahead to next week, much cooler air is expected to arrive behind a Canadian cold front Monday night.  Ahead of the front, the weather will be mostly sunny and quite warm with temperatures reaching the low 90s.  With low moisture levels in place, little to no rain is expected with the cold front Monday night.  Low temperatures Tuesday morning are forecast to fall to the middle and upper 50s.  The weather next Tuesday is forecast to be sunny and noticeably cooler with high temperatures in the mid and upper 70s.

These cooler temperatures are forecast to hang around for most of next week as a large trough of low pressure in the upper atmosphere becomes stationary over the central US, allowing cool air to spread south out of western Canada.

Here is a look at the Jet Stream (500 MB) level of the atmosphere for next Tuesday, April 29th, from the European Center for Medium Range Forecasts:
                     
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Note the large trough becoming blocked by ridges of high pressure along the West and East Coasts.  The European model suggests this general pattern will last through late next week, allowing additional cool air to spread south out of Canada.  Daily high temperatures will be in the 70s with low temperatures mostly in the 50s.  I wouldn't be surprised to even see some 40s across the Hill Country.  Weather conditions throughout the week will be sunny and dry.

Looking out longer term, this pattern looks to modify some the following week.  Temperatures look to stay near to slightly below normal and there are some hints the pattern may begin to turn wetter across Texas.  Stay tuned for more details about this possible surprising development.

Bob

Previous Blog Entries

Happy Earth Day!
Tuesday, April 22, 2014 11:47 AM

 
Happy Earth Day!  In celebration of Earth Day, here is a beautiful full disk view of the Western Hemisphere of Earth taken at 9:45 am CDT Tuesday morning.  This image was captured by the GOES 13 weather satellite and is courtesy of GOES Project Science.  If you look closely, you can see the sun beginning illuminate the Pacific Ocean to the west of North America.  This is what sunrise looks like as it spreads from east to west.

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A quick update on Monday's night's rainfall.  A persistent area of strong to severe thunderstorms across parts of the Hill Country produced a narrow corridor of 1-inch rainfall across Mason, southern Llano, northern Gillespie and eastern Kimble Counties.  According to LCRA's Hydromet, the highest gauged total was 2.19 inches at a location 14 miles southeast of Junction, in Kimble County.  In addition to the rain, many of the storms produced very large hail and strong winds.  These thunderstorms remained over the Hill Country and didn't affect the rest of the region.  In Austin, Camp Mabry recorded just 0.01 inches and Austin-Bergstrom recorded only a trace of rain.

 

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I'll have a more complete on the weather later this afternoon.

Bob

Midday Monday Weather Update
Monday, April 21, 2014 1:25 PM

Here is a look at weather conditions for this week and an outlook for next week.

Warm temperatures will be in place all week with daily high temperatures generally in the low and middle 80s.  Readings may turn even warmer this coming weekend before cooler air arrives behind a cold front early next week.  Unfortunately, there will be few opportunities for rain this week.  A few scattered strong to severe thunderstorms will be possible across parts of the Hill Country and Central Texas late this afternoon and evening.  Another slight chance for thunderstorms will also occur Thursday afternoon and next Sunday.  But rain amounts for all 3 periods will be very low.  Today's forecast solutions don't call for any widespread, significant rain across Central Texas over the next 10 days.

Here's  day by day breakdown of this week's expected weather:

Widespread low clouds covering most of Central Texas and the middle Texas coast this morning are forecast to slowly burn off this afternoon.  The sky should become partly cloudy by mid afternoon.  Southerly winds will increase to a range of 10-15 mph in the afternoon.  Today's temperature will warm to the low and middle 80s.

A weak wave of low pressure tracking east across North Texas in combination with a weak cold front sagging south out of the Texas Panhandle is expected to cause the development of scattered thunderstorms across parts of North Texas this afternoon.  These developing thunderstorms are forecast to track southeast, potentially affecting parts of the Hill Country and the northern counties of Central Texas late this afternoon and evening.  Should thunderstorms develop, they will have the potential to become severe, producing large hail and damaging winds.  The Storm Prediction Center has placed much of the Hill Country and the northern counties of Central Texas, including the Austin Metro area, in a Slight Risk for severe thunderstorms this afternoon and evening:

Storm Prediction Severe Weather Outlook for the Period from 11:30 am Monday through 7 am Tuesday:

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The chance for rain this afternoon and evening will be near 40 percent across the northern Hill Country and near 20-30 percent across the rest of the region.  Spotty rain amounts to near a half inch are forecast.  Any thunderstorms which happen to develop will likely dissipate by midnight as temperatures cool.  Low temperatures Tuesday morning will be in the low and middle 60s.

A pattern of late night and morning clouds followed by a partly cloudy sky in the afternoon is forecast for Tuesday through Friday.  Daily high temperatures will generally be in the mid 80s and low temperatures will generally be in the mid 60s.  There will be another slight chance for thunderstorms Thursday afternoon and evening as a weak cold front sages south out of northwest Texas.  However, the chance for rain will only be 20 percent.

Partly cloudy and slightly warmer weather looks to continue this weekend with high temperatures expected to be in the upper 80s to 90 degrees.  Scattered thunderstorms are forecast Sunday into Monday ahead of a Canadian cold front.  Today's data does not indicate there will be widespread rain.  The front will bring cooler temperatures for next Tuesday through Thursday with high temperatures in the 70s to 80 degrees and low temperatures in the 50s.

Bob

A Very Slight Chance for Rain this Weekend. Dry and Warm Next Week.
Friday, April 18, 2014 4:56 PM

The light rain and drizzle which developed across most of Central Texas late Thursday didn't amount to all that much with most amounts totaling less than a tenth of an inch.  The weather looks to stay fairly quiet through the weekend with just a slight chance for rain expected Saturday night, Easter Sunday and on Monday.  Next week's weather is shaping up to be generally dry and warm.  Temperatures will be warmer, peaking in the mid and upper 80s mid and late week.

Here is a day by day breakdown of expected weather conditions for the next 7 days:

The sky will be partly to mostly cloudy overnight.  Low temperatures Saturday morning will be in the mid and upper 50s with light east winds at 5-10 mph.  The sky will start off partly cloudy on Saturday but will slowly become mostly cloudy in the afternoon ahead of a trough of low pressure located over the southwestern US.  This system is expected to pull clouds and moisture north from the Gulf and eastern Pacific late Saturday into Saturday night.  Saturday's weather will be dry with afternoon temperatures reaching the upper 70s.  Expect light southeasterly winds at 5-10 mph.

The trough of low pressure over the southwestern US is forecast to move to the southern Plains states between Saturday and Monday.  With the system staying that far to the north, the most favorable area for rain will likely occur across the Texas Panhandle and into Oklahoma and not across South Texas.  However, increasing moisture and weak atmospheric lift across the Hill Country and Central Texas regions is expected to cause the development of a few scattered rain showers and isolated thunderstorms beginning Saturday night, continuing through Sunday.  The chance for rain will only be at 20 percent and rain amounts will be less than a quarter inch.  Much of Easter Sunday is forecast to be just cloudy, breezy and warm.  The low temperature Sunday morning will be around 60 degrees and the high temperature Sunday will be in the upper 70s.  By the way, sunrise Sunday morning in Austin will be at 6:58 am CDT.

There will be another slight chance for rain showers and isolated thunderstorms Monday when a weak cold front sags south out of North Texas and pulls up stationary across Central Texas.  The chance for rain will again only be 20 percent and potential rain totals will be very low.  Monday's sky will be mostly cloudy and high temperatures will be in the low 80s.

National Weather Service Rainfall forecast for the period from Friday evening through Monday evening:
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Partly cloudy, warm and generally dry weather is forecast next Tuesday through Friday as a weak ridge of high pressure in the upper atmosphere sets up across Texas.  There are indications the West Texas Dry Line may surge east towards the Hill Country next Wednesday and Thursday, possibly triggering a few afternoon thunderstorms.  But confidence in this development is currently very low.  The high temperature Tuesday will be in the mid 80s.  High temperatures look to rise to the mid and upper 80s next Wednesday through Friday.

The next significant chance for rain across our region looks to occur around Monday, April 28th.  At that time, a trough of low pressure and a cold front are forecast to track east across Texas.  There are some indications cooler temperatures may return to the area around the first of May.

Have a good weekend.          

Bob

Mild Readings this Weekend; Turning Warmer Next Week.
Thursday, April 17, 2014 6:23 PM

On Thursday, the National Weather Service's Climate Prediction Center updated its 3-month drought outlook and for much of Texas, the outlook is pretty grim.  For the period from mid April through the end of July, drought conditions are forecast to persist across the western two-thirds of Texas. For areas roughly to the west of a line stretching from Victoria to Fort Worth, including the Austin area, drought conditions are forecast to persist or intensify:

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Areas to the east of this line are forecast to be in better shape over the next 3 months, and drought removal is expected.  CPC forecasters note the drought has become entrenched across the western two thirds of Texas and no significant change in the weather pattern is forecast in the upcoming period.  Rainfall is expected to be more substantial across the eastern third of the state.  The forecasters note enhanced odds for the development of above normal temperatures over the next 3 months, possibly causing drought conditions to intensify.  But do note that historically, the months of May and June are typically the wettest 2 months of the year across Central and South Texas and there is some thought rains over the next 2 months could help ease long-term drought conditions.

Also on Thursday, the International Research Institute in cooperation with the CPC updated the long-term outlook for the development of El Nino.  In the most recent update, the probability for the development of El Nino late this summer and fall has increased to more than 70 percent.

 

 

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This is good news for our long-term forecast.  El Ninos typically cause a pattern of above normal rainfall across most of Texas in the fall and winter seasons.  Today's updated outlook gives forecasters even greater confidence a wetter weather pattern will develop this fall and winter.  But do keep in mind that a developing El Nino in the summer often limits the development of tropical storms and hurricanes across the Atlantic basin.

A visible satellite image from Thursday afternoon showed widespread clouds covering the central part of the state with a mostly sunny sky across West and East Texas:

 

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The large area of clouds resulted from Gulf moisture being pulled north into Texas by a weak wave of low pressure located along the Red River in North Texas.  This system caused a few light rain showers across Central Texas on Thursday and some additional light sprinkles will be possible through Thursday evening.  However, all of the precipitation should end by late evening as the week disturbance exits to the east.  Low temperatures Friday morning will be in the mid and upper 50s.

By the way, note the large area of clouds located over the north central Gulf of Mexico.  These clouds are associated with a second trough of low pressure in the upper atmosphere that was located over the central Gulf.  This trough was causing the development of a widespread area of rain showers and thunderstorms over the northern Gulf.  Forecast solutions call for the trough of low pressure over the Red River Valley to combine with the trough over the Gulf of Mexico on Friday.  The combined system is forecast to produce a large area of heavy, soaking rains over the southeastern US and Florida as it tracks to the east Friday through Saturday.

Today's forecast data shows few changes in the outlook for Friday and this weekend.  A more stable weather pattern looks to develop Friday in the wake of Thursday's departing wave of low pressure.  The sky will become mostly sunny in the afternoon and the temperature will warm to the upper 70s.  But widespread clouds will return Saturday ahead of a large trough of low pressure in the upper atmosphere that will be pushing inland along the coast of southern California.  This system is forecast to track northeast, reaching a position over the southern Plains states by late Sunday.  The approaching through combined with increasing moisture will cause a very slight chance for rain showers beginning Saturday night.  A 30 percent chance for rain showers and isolated thunderstorms is forecast Easter Sunday and Sunday evening.  Today's forecast data indicates a slight chance for rain showers will linger into Monday then diminish Monday night.  The latest National Weather Service rainfall forecast continues to indicate rain totals will be low, generally at of less than 0.25 inches.  High temperatures Saturday and Sunday will be near 78-80 degrees.  High temperatures Monday will be in the low 80s.  Weekend low temperatures will be in the low and mid 60s.

Today's medium-range outlooks indicate the weather will be partly cloudy, dry and warm next Tuesday through Friday as a weak ridge of high pressure builds north across Texas.  There are some indications the West Texas Dry Line may push east out of West Texas during the middle of the week, possibly causing a few scattered thunderstorms.  But as of now, the chance for rain will be low.  High temperatures next Tuesday through Friday are shaping up to be in the upper 80s with low temperatures in the mid 60s.  Conditions don't appear favorable for rain through late next week and next weekend.

Bob

Warmer Temperatures Returning. A Slight Chance for Rain Developing this Weekend.
Wednesday, April 16, 2014 6:35 PM

Temperatures were unseasonably chilly early Wednesday morning thanks to a clear sky, dry air, and light winds.  According to LCRA's Hydromet, (http://hydromet.lcra.org) temperatures fell to the mid and upper 30s across the eastern Hill Country and most of Central Texas.   A few locations even recorded temperatures below freezing.  
 
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The lowest recorded temperature was 29 degrees at 2 separate locations located in northeastern and southern Llano County.  In Austin, the low temperature at Camp Mabry was 40 degrees.  But at Austin-Bergstrom, the temperature reached 32 degrees, breaking the record of 37 degrees set in 2007.  Interestingly, light southerly winds kept temperatures across a large part of the Hill Country from dropping below the low 40s.  Across the middle Texas coast, readings generally reached the low 40s.  For example, the low temperature at Victoria was 40 degrees, tying the record of 40 degrees set in 1928.   Keep in mind, the average low temperature for the middle of April is 59 degrees.  The average high temperature is 80 degrees.

The large dome of Canadian high pressure which brought the unseasonable cool weather to Texas on Monday shifted to the East and Northeastern US this afternoon.  A clockwise circulation around the high pressure system has brought the return of southerly winds and slightly warmer temperatures.  Rising humidity levels will cause the development of widespread low clouds after midnight.  Low temperatures Thursday morning will generally be in the low and mid 50s.

Our recent spell of cool, quiet weather will be changing over the next couple of days as Gulf moisture continues to spread inland off the Gulf.  On Thursday, a small trough of low pressure tracking east across the southern Plains states will help push a weak cold front into North Texas.  Atmospheric moisture levels will increase enough ahead of the cold front to produce a few widely scattered light rain showers Thursday and Thursday night.  Rain amounts, if any, will be very low.  The sky is forecast to remain mostly cloudy Thursday with the temperature generally reaching the low and middle 70s.  Low temperatures Friday morning will be in the upper 50s.

The sky should become partly cloudy Friday as weak trough of low pressure exits to the east and the flow of Gulf moisture decreases.  Friday's temperature will climb to the upper 70s.

There appears to be another change in the weather pattern this weekend when a large trough of low pressure in the upper atmosphere tracks inland along the coast of southern California and northwestern Mexico.  This system is expected to pull moisture north from the Pacific and Gulf of Mexico into Texas, causing a mostly cloudy sky.  Saturday's weather will dry with high temperatures in the upper 70s.  Low temperatures Sunday morning will be in the low and mid 60s.  Increasing moisture and atmospheric lift associated with the approaching upper trough is forecast to cause the development of scattered rain showers and isolated thunderstorms across the area beginning Saturday night and continuing through Sunday night.  As of today, conditions don't appear favorable for the development of severe thunderstorms.  The most favorable period for rain will likely occur Sunday afternoon.  The chance for rain during this period will be near 30-40 percent.

Today's forecast data indicates the chance for rain will end late Sunday night as the upper trough exits to the east.  A broad, stable ridge of high pressure in the upper atmosphere is forecast to build north and set up over Texas all of next week.  The ridge will cause a mostly sunny to partly cloudy sky, warm temperatures and dry weather next Monday through Friday.  Daily high temperatures look to be mostly in the mid 80s with low temperatures generally in the mid 60s.  It appears the next significant chance for rain will occur sometime next weekend when another trough of low pressure tracks northeast out of Mexico.  I don't see any additional unseasonably cool weather headed our direction over the next 10 days.  It appears spring-like temperatures will really begin to set in next week.

TOTAL LUNAR ECLIPSE:  (Courtesy of Spaceweather.com)  On April 15th, all of the sunrises and sunsets on Earth got together and painted the Moon red. In other words, there was a total lunar eclipse. "The Moon turned a coppery orange during mid-totality," says Steve Engleman who sends this picture from Richardson, Texas:

 

 

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During the early hours of April 15th, the Moon spent more than three hours gliding through the shadow of Earth. The Moon turned red during the transit because the core of our planet's shadow is red.

Why red? A quick trip to the Moon provides the answer: Imagine yourself standing on a dusty lunar plain looking up at the sky. Overhead hangs Earth, nightside down, completely hiding the sun behind it. The eclipse is underway. 

You might expect Earth seen in this way to be utterly dark, but it's not. The rim of the planet is on fire! As you scan your eye around Earth's circumference, you're seeing every sunrise and every sunset in the world, all of them, all at once. This incredible light beams into the heart of Earth's shadow, filling it with a coppery glow and transforming the Moon into a great red orb. 

If you missed it, don't worry. Three more lunar eclipses are in the offing. Get the full story from NASA Science News, http://science.nasa.gov/science-news/science-at-nasa/2014/27mar_tetrad

Bob

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