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Bob's Blog on Central Texas Weather

Gulf Moisture will Cause Periods of Rain and Thunderstorms through Tuesday.
Friday, August 26, 2016 5:24 PM


The weather pattern is trending more unsettled as we head into the weekend.  Tropical moisture will be spreading inland off the Gulf of Mexico and this moisture is expected to fuel scattered to numerous rain showers and thunderstorms across the region beginning this afternoon, continuing through the first half of next week.  Today's weather maps showed a broad ridge of high pressure located over the eastern US and a large trough of low pressure situated over the southern Rockies.  The circulation around both features is causing a southeasterly wind flow in the lower atmosphere from the Gulf of Mexico into Texas.  This morning, a deep layer of tropical moisture is shown to be slowly spreading from the coastal plains region northwest toward the Interstate 35 corridor.  This area of moisture is forecast to spread northwest over the Hill Country region tonight and Saturday.  With the atmosphere becoming increasingly moist and unstable, scattered rain showers and isolated thunderstorms are forecast to develop.  Most of this activity will occur from the late morning through the evening, but a few spotty rain showers will also be possible in the overnight hours.

Today's analysis showed a weak area of low pressure is attempting to develop over the north central Gulf of Mexico.  This system is weak and very disorganized.  Surface pressures over the western Gulf are high and there is only a very slight chance this low might acquire tropical characteristics before moving inland over South Texas Sunday into Monday.  The National Hurricane Center is only giving this system a 10 percent chance for tropical development over the next 48 hours.  The low is expected to pull a large slug of moisture inland Sunday and Monday, enhancing the chance for rain across our region.  Due to tropical nature of this low and the abundant moisture in place, some locally heavy downpours will be possible Saturday through Monday.  The low is forecast to weaken and track toward northern Mexico beginning Tuesday, taking much of the moisture with it.

  • For this afternoon and tonight, scattered rain showers and thunderstorms are forecast to develop.  The highest probability for rain will be across the coastal plains region, with somewhat less activity expected across Central Texas and the Hill Country.  The probability for rain will range from 50 percent at the coast to near 40 percent across Central Texas to 20 percent across the Hill Country.  Expect a partly to mostly cloudy sky with a high temperature near 90-92 degrees.  Most of today's rain activity should diminish around sunset.  Rainfall will generally average between 0.25 and 0.5 inch, with isolated totals of 1-2 inches possible.
 
  • For Saturday, the sky is forecast to remain mostly cloudy throughout the day.  There will be a 40-50 percent chance for scattered rain showers and thunderstorms across Central Texas and the coastal region and a 30 percent chance for rain showers across the Hill Country.  Much of the activity should diminish Saturday evening.  Rainfall is forecast to average between 0.25 and 0.5 inch, with isolated totals of 1-2 inches possible.  Saturday's temperature is forecast to reach near 88-90 degrees.
 

  • A more widespread  coverage of rain showers and thunderstorms is forecast across the entire region Sunday through Monday as the weak area of low pressure tracks west from the Gulf of Mexico. The probability for rain will range from 70 percent along the coast to 40 percent across the Hill Country.  Some heavy downpours will be possible both days.  2-day rainfall are forecast to average between 1 and 2 inches across the coastal plains, around 1 inch across Central Texas and between 0.5 and 1 inch across the Hill Country.  Isolated totals of 3-4 inches will be possible.  High temperatures both days will be in the upper 80s.

     
  • The chance for widespread rain is expected to decrease Tuesday as moisture levels decrease.  However, there will still be a 30 percent chance for rain showers and thunderstorms across the region.   Rainfall will generally average between 0.25 and 0.5 inch, with isolated totals to near 1 inch.  Tuesday's sky will be partly cloudy and the temperature should reach the low 90s.
 
Today's forecast solutions call for just a slight chance for rain showers Wednesday as the atmosphere dries out.  Mostly sunny and dry weather is forecast next Thursday and Friday.  High temperatures Wednesday through Friday are forecast to be in the low to mid 90s.  A broad ridge of high pressure is forecast to set up over Texas late next week and continue through the Labor Day weekend.  Today's forecast data calls for sunny, dry and warm weather over the holiday weekend.  High temperatures look to be in the mid to upper 90s.

Tropical Weather Update
Forecasters continue to monitor the progress of a strong tropical wave and weak area of low pressure extending from the northeastern coast of Cuba and the central Bahamas.  The associated shower and thunderstorm activity did increase some Friday afternoon, but it remains disorganized and is located mainly to the east and southeast of the low.  Strong upper-level winds over the past couple of days have kept the system from organizing.  Conditions are expected to remain unfavorable for significant development through Sunday as the system moves west-northwestward between Cuba and southern Florida at about 10 mph.  Environmental conditions are expected to become a little more conducive for tropical development Monday when the system moves into the eastern Gulf of Mexico.  The majority of today's forecast solutions call for the system to track northwest toward Alabama or the Florida Panhandle the middle of next week.  There is little support for a track west towards the Texas coast at this point.  Nevertheless, this system will need to be watched closely for development.  NHC forecasters are giving this system a 60 percent chance for tropical development over the next 5 days.

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Tropical Storm Gaston was located over the central Atlantic Friday afternoon, about 1000 miles east-southeast of Bermuda.  Maximum sustained winds were  near 65 mph.  Gaston is moving toward the northwest at 17 mph.  The system is expected to continue in this general direction for but at a slower rate of forward speed during the next couple of days.  Some strengthening is forecast and Gaston should become a hurricane on Saturday.  Gaston is forecast to track well east of Bermuda into the open Atlantic, posing no threat to any land areas.

Weather conditions across the rest of the Atlantic, Caribbean Sea and the Gulf of Mexico are quiet.  There are no systems in place which pose a threat for tropical development over the next 5 days.

Bob

Previous Blog Entries

Scattered Rain Showers Expected through the Middle of Next Week.
Thursday, August 25, 2016 5:50 PM

A fairly typical late August weather pattern continues across Central and South Texas.  While afternoon temperatures have been warm for the past few days, they've actually been slightly below normal for this time of the year.  Some changes to the current pattern are forecast beginning Friday as circulation around a ridge of high pressure along the East Coast pulls tropical moisture into Texas off the Gulf of Mexico.  This feed of moisture will likely cause the development of scattered rain showers and thunderstorms across the region through the middle of next week.

A visible satellite image from late Thursday afternoon showed scattered thunderstorms clouds along the middle and upper Texas coastal plains where the leading edge of the tropical moisture had spread inland.  Additional clouds can be seen over the western and Central Gulf of Mexico, associated with a weak non-tropical area of low pressure.
  
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With a slightly unstable atmosphere in place, Gulf moisture spreading into Texas is expected to cause a daily chance for rain and thunderstorms across the region.  The most favorable area for rain through the period will be across the coastal plains region, with less activity expected across Central Texas and even less expected across the Hill Country.

For Friday and Saturday, the probability for scattered rain showers and thunderstorms will range from 50 percent near the coast to around 40 percent across Central Texas to near 20 percent across the Hill Country.  2-day rainfall totals are forecast to average around a half inch across the coastal plains and around a quarter inch at most other locations.  Isolated totals of 1-2 inches will be possible.  Expect a partly to mostly cloudy sky with high temperatures in the low 90s.

The chance for rain and thunderstorms will increase Sunday into Monday when the weak area of low pressure over the Gulf of Mexico pushes inland and slowly tracks to the west.  The chance for rain looks to be near 40-50 percent at most locations and 2-day rain amounts are forecast to average between 0.25 and 0.50 inch.  Isolated totals of 1-2 inches will again be possible.  The sky will be mostly cloudy both days with high temperatures near 90 degrees.

A slight chance for rain showers is forecast to continue next Tuesday and Wednesday as tropical moisture lingers across the area.   Rain amounts are forecast to average around a quarter inch, or less.  Expect a partly cloudy sky with high temperatures mostly in the low 90s.

Total rain amounts over the next week are not expected to be all that heavy.  The National Weather Service's rainfall forecast for the period from 7 pm Thursday through 7 pm next Thursday are forecast to average near 1-1.5 inches across the coastal plains, around a half inch across Central Texas and close to a quarter inch across the Hill Country. 

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Long-range forecast solutions call for the development of a generally dry and warm weather pattern late next week into next weekend when a broad ridge of high pressure in the upper atmosphere develops across Texas and the southern Plains states.  Circulation around the ridge is expected to decrease the flow of tropical moisture into Texas.  High temperatures late next week are forecast to be in the low to mid 90s.  There are some signs a few showers may return to the forecast beginning around Labor Day.

Tropical Weather Update

Forecasters continue to monitor the progress of a strong tropical wave located in the southeastern Bahamas and tropical storm Gaston, located in the central tropical Atlantic.

FMA.png                                                                                            NOAA-NASA GOES Project

The strong tropical wave remains a disorganized system and has so far failed to develop into tropical cyclone.  The tropical wave and an associated broad area of low pressure was centered Thursday afternoon just north of the Hispaniola and was moving westward at 15 to 20 mph through the southeastern Bahamas.  Satellite wind data and reports from an Air Force Reserve reconnaissance aircraft this morning indicated the system still lacked a closed circulation, and that the strongest winds associated
with the system likely had decreased to below tropical storm strength. In addition, shower and thunderstorm activity had become
significantly less organized during the past 24 hours due to increased wind shear.  NHC forecasters pointed out that although upper-level winds are not conducive for significant development during the next day or so, they could become a little more favorable over the weekend or early next week when the wave is expected to approach southern Florida or the southeastern Gulf of Mexico.  NHC forecasters are giving this system a 70 percent chance for tropical development over the next 5 days.  The majority of the long-range computer guidance suggests this system, whether it develops or not, will most likely track toward the eastern Gulf of Mexico, and not westward towards Texas.  Nevertheless, the progress of this system will need to be monitored closely.

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Tropical storm Gaston continues to churn across the central tropical Atlantic.  Late Thursday afternoon, Gaston was centered about 1105 miles east-northeast of the Leeward Islands, moving to the northwest at 17 mph.  Maximum sustained winds were near 65 mph.  Strong southwesterly winds in the upper atmosphere over the past 24 hours caused Gaston to weaken.  Little change in strength is forecast through Friday afternoon, but the system is forecast to strengthen into a hurricane Saturday, when it moves into a more favorable environment.  Long-range forecasts call for Gaston to remain over the open Atlantic for the next several days, not threatening any land areas.

Bob
  
A Slight Chance for Rain Late Week and this Weekend. Watching the Tropics.
Tuesday, August 23, 2016 5:56 PM

There has been a noticeable change in the weather across Central Texas since Monday.  The deep flow of moisture off the Gulf of Mexico that has been in place for more than a week shifted west to Mexico and Far West Texas Monday night.  At the same time, a weak ridge of high pressure in the upper atmosphere spread over the eastern half of Texas out of the Gulf of Mexico.  Both of these factors caused the atmosphere to become more stable and allowed for scattered sunshine and warmer temperatures.

A visible satellite image from late Tuesday afternoon showed only scattered clouds across the eastern two-thirds of the state, while clouds and showers persisted across the Panhandle and Far West Texas. 
 
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Similar weather conditions are forecast Tuesday.  Sunny, warm and humid weather will continue with high temperatures in the low to mid 90s.

Some changes in the weather pattern are forecast to take place Thursday and through the weekend as the ridge of high pressure shifts to the northeast, allowing an area of moisture to spread inland off the Gulf of Mexico.  This next area of moisture isn't expected to be nearly as deep as what we saw last week and last weekend.  As a result, the increased moisture should cause the development of some scattered rain showers and isolated thunderstorms throughout the upcoming period, but the rain shouldn't be nearly as widespread or as heavy as what we saw earlier.  The daily probability for rain will be near 20-30 percent.  Expect a partly cloudy sky with high temperatures mostly in the low 90s.  This slight chance for rain looks to continue through the middle of next week.

Rainfall over the next seven days is not expected to be all that heavy.  The National Weather Service's rainfall forecast, for the period from 7 pm Tuesday through 7 pm next Tuesday calls for totals to near a half inch across the Hill Country and Central Texas regions and to near 1 inch across the middle Texas coast:
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Keeping a Close Watch on the Tropics


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                                                                                        NOAA-NASA GOES Project


Forecasters are monitoring the progress of a strong tropical wave located over the west-central tropical Atlantic, a few hundred miles east of the Lesser Antilles.  This system has shown signs of organization for the past couple of days.  Tuesday afternoon, Air Force Reserve Hurricane Hunter aircraft investigated the tropical wave and found the system had an elongated and poorly defined circulation.  Satellite imagery indicated the associated shower and thunderstorm activity remained disorganized, so the system remains below the threshold for a tropical depression. Environmental conditions are currently only marginally conducive for development during the next couple of days while the system moves west-northwestward at 15 to 20 mph.  However, large-scale conditions could become more conducive for rapid development later this week while the system moves nears the southeastern and central Bahamas. Another Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate this disturbance on Tuesday.  NHC forecasters are giving this system a 60 percent chance for tropical development over the next 5 days.

The National Hurricane Center's 5-day outlook calls for this system to track northwest toward the Bahamas and southern Florida late week and into the weekend.  This system will need to be watched as some long-range solutions call for the system to strengthen into a hurricane and cross into the eastern Gulf of Mexico.  Stay tuned for more developments.

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To the east of the tropical wave we find tropical storm Gaston.  Gaston is located 765 miles west of the Cabo Verde Islands and is moving to the west-northwest at 18 mph.  A gradual turn to the northwest and a decrease in forward speed is forecast over the next couple of days.  Maximum sustained winds are near 65 mph and further strengthening is forecast.  Gaston is expected to become a hurricane Tuesday night or Wednesday.  Forecasts call for Gaston to turn northwest into the open Atlantic and it should have no effect on any land areas.

Bob

A Drier Trend through Thursday But A Chance for Rain Returning for the Upcoming Weekend.
Monday, August 22, 2016 4:49 PM

It was a wet and soggy weekend across Central and South Texas as another unusual August cold front pushed south into the area.  According to rainguage and rainfall esitimates, most totals averaged between 1 and 2 inches.  However, a few spots across Bastrop, Lee and Gonzales Counties measured more than 6 inches.

 

NWS estimated rain falling between 2 pm Friday and 2 pm Monday:

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Today's analysis showed this weekend's cold front has moved back to the north and was located close to the Red River, along the border between Oklahoma and Texas.  Meanwhile, a southerly wind flow continues to pull considerable moisture north from the Gulf of Mexico into Texas.  A small wave of low pressure embedded within this moist flow pushed north from the coast this morning, causing an area of rain showers and thunderstorms.  With a very moist atmosphere in place, scattered rain showers and isolated thunderstorms are developing this afternoon across the region and this activity should continue into this evening.  The probability for rain will be near 40 percent.  Today's rain showers are not expected to all that heavy or organized.  Most totals should average between 0.25 and 0.5 inch but a few isolated totals to near 1 inch will be possible.  Most of the rain activity should diminish around sunset.  Today's sky will be partly to mostly cloudy and the high temperature will be near 88-90 degrees.

A weak ridge of high pressure centered over the southeastern US is forecast spread west into Texas Tuesday, causing our atmosphere to become drier and more stable.  Mostly sunny and dry weather is expected across the Hill Country and Central Texas regions Tuesday through Thursday.  However, a few spotty rain showers will still be possible each day across the coastal plains region.  Daily rain amounts should remain below a quarter inch.  Tuesday's high temperature looks to be near 90 degree.  High temperatures Wednesday and Thursday are forecast to be in the low 90s.  The pressure gradient across the state is forecast to strengthen slightly Tuesday into Wednesday.  This should result in a bit stronger southerly winds in the range of 10-15 mph.  Winds speeds should fall back to around 5-10 mph on Thursday.

The ridge of high pressure is forecast to shift to the east Friday and through the weekend as a trough of low pressure dips south into the Plains states out of West Canada.  Circulation around both features is expected pull a large area of tropical moisture north into Texas.  This will result in the development of scattered rain showers and thunderstorms beginning Friday, continuing through Sunday.  While this may sound similar to the pattern of this past weekend, it will likely be different.  A cold front associated with the approaching trough is forecast to stall over Oklahoma, so moisture convergence and rainfall shouldn't be as heavy or as widespread across our region.  Scattered mainly afternoon and evening showers and thunderstorms are forecast Friday through Sunday.  The probability for rain each day will near 30 percent.  As of now, rainfall over the 3-day period is forecast to average around a half inch or less.  Expect a partly to mostly cloudy sky with high temperatures around 90 degrees.

Looking ahead to next week, it appears a slight chance for rain will continue across the region throughout the week.  Today's forecast solutions indicate our region will remain under the influence of a very moist flow off the Gulf of Mexico.  In the upper atmosphere, a weak ridge of high pressure is forecast to be situated over the southeastern US, but not over Texas.  The combination of abundant moisture and a slightly unstable atmosphere will lead to a slight chance for rain each day.  Expect a partly cloudy sky with high temperatures in the low and middle 90s.  There are no indications we'll see any triple-digit temperatures over at least the next 10-day period.

Tropical Weather Update
Forecasters continue to monitor several features in the tropical Atlantic.

CPCOutlk.png                                                                                                        NOAA-NASA GOES Project

Tropical storm Fiona weakened to a tropical depression Sunday as the system encountered considerable wind shear.  This afternoon, the depression was located over the open Atlantic, about 615 miles south-southeast of Bermuda.  Maximum sustained winds were near 35 mph with some higher gusts.  Gradual weakening is forecast over the next 48 hours as the depression encounters additional wind shear.  Fiona is expected to weaken to a remnant low pressure area within the next 48 hours.  The system is moving to the west-northwest at 17 mph.  This general motion and a decrease in forward speed is forecast later today and Tuesday.

Forecasters continue to monitor the large tropical wave that was located over the eastern tropical Atlantic late last week.  As of this afternoon, the wave had moved to the central Atlantic and was located about 750 miles east of the Lesser Antilles.  The disturbance is producing disorganized shower and thunderstorm activity and nearby dry air is expected to slow the system's  development over the next couple of days.   The wave is moving westward to west-northwestward at 15 to 20 mph.  Environmental conditions are forecast to become more conducivefor development late this week when the system is expected to move near Hispaniola and the southeastern and central Bahamas.  NHC forecasters are giving this system a 50 percent chance for tropical development over the next 5 days.  An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate this system on Tuesday, if necessary.  Long-range forecasts for this system have trended more to the north over the past couple of days.  The National Hurricane Center's 5-day forecast now calls for the system to move toward Hispaniola and the Bahamas late this week.  A track toward the Gulf of Mexico doesn't appear as likely at this time.

The strong tropical wave and its associated area of low pressure area located west-southwest of the Cabo Verde Islands in the eastern tropical Atlantic has developed a well-defined circulation and sufficient organized convection to be considered a tropical depression.  Microwave imagery suggests that the system is likely still consolidating but it is showing good organization.  As of late Monday afternoon, the depression was centered about 360 miles west-southwest of the southern Cabo Verde Islands.  The depression is moving to the west at 18 mph.  A turn to the west-northwest is forecast Tuesday.  Maximum sustained winds are near 35 mph.  Strengthening is forecast and the depression is forecast to become tropical storm Gaston Monday night or on Tuesday.  The National Hurricane Center's 5-day forecast to the depression calls for the system to turn northwest into the open Atlantic over the next 3 days.  On this path, the depression will pose little to no threat to the Gulf of Mexico.

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Elsewhere, weather conditions are quiet and there are no systems which pose a threat for tropical development over the next 5 days.

Bob

An Increasing Chance for Rain this Weekend. Signficant Totals Possible.
Friday, August 19, 2016 3:52 PM

The unusual wet August weather pattern we've been experiencing since late last week is expected to continue this weekend and early next week.   The month of August is typically the second driest month of summer across much of the region, but this month already ranks as the twelfth wettest August on record at Austin-Camp Mabry and there is still a week and a half to go.

Early afternoon satellite images showed scattered clouds covering the sky across Central Texas and the middle Texas coast, while considerable clouds were in place across the Hill Country.  A weak wave of low pressure moving northeast out of the Texas Big Bend was responsible for the clouds and some spotty light showers across the Hill Country and much of West Texas.  Additional spotty rain showers and a couple of thunderstorms are forecast to continue across the Hill Country this afternoon and evening as the wave of low pressure slowly moves off to the northeast.  Rain amounts should average around a quarter inch.  Across Central Texas and the middle Texas coast, the sky will be partly to mostly cloudy this afternoon.  Scattered rain showers and isolated thunderstorms are forecast due to lingering tropical moisture.  But due to the lack of a significant trigger, areal coverage and intensity of the rain shouldn't be as great as what we've seen over the past few days.  The probability for rain will be near 30 percent and rain amounts should total between 0.25 and 0.5 inch.  Today's high temperature is forecast to be near 88-90 degrees.

Rain and thunderstorms are forecast to increase in coverage and intensity across the Hill Country and Central Texas regions Saturday morning into Saturday afternoon in advance of a large trough of low pressure dropping south into the southern Plains states.  Tropical moisture off the Gulf of Mexico and eastern Pacific will stream north into Texas, keeping the atmosphere very moist and unstable.  A cold front associated with the upper trough is forecast to push south into North Texas Saturday afternoon, pulling up stationary somewhere around Interstate 20 Saturday evening.  Moisture convergence out ahead of the cold front is expected to cause the development of numerous rain showers and thunderstorms beginning Saturday morning, continuing through Sunday and most of Monday.  Today's forecast data indicates the most favorable area for rain and the heaviest rains should occur across the Hill Country and West Central Texas.  Slightly less coverage is forecast across Central Texas and the middle Texas coast.  Severe storms are not anticipated but some of the storms may produce strong and gusty winds along with dangerous lightning.

Friday morning's forecast data is calling for significant totals of rain occurring between Saturday morning and late Monday as the front remains stationary over North Texas.  With a very moist atmosphere in place, the rain process is expected to be very efficient.  National Weather Service 3-day rainfall forecasts are generally calling for totals of 3-5 inches across the Hill Country, around 2-3 inches across Central Texas and around 1-2 inches across the coastal plains.  However, isolated totals of 6-8 inches or more will not be out of the question.

NWS rainfall forecast for the period from 7 pm Friday through 7 pm Monday
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With the ground still wet from this week's rain, any additional rain will not soak into the ground and quickly runoff.  This could lead to a dangerous flash flood situation.  The National Weather Service may post a Flash Flood Watch for the area later today or on Saturday.  High temperatures Saturday through Monday will be in the mid to upper 80s.

The chance for widespread rain and thunderstorms is expected to decrease Tuesday as the cold front over North Texas lifts back to the north and a weak ridge of high pressure begins building across Texas out of the Gulf of Mexico.  A few scattered rain showers will still be possible Tuesday but generally dry and sunny weather is forecast Wednesday through Friday.  High temperatures Tuesday will be around 88-90 degrees.  Readings should reach the low 90s for the remainder of next week.

Today's long-range data continues to call for slightly below normal temperatures from late August into early September.  There are no indications we'll see a return to triple-digit temperatures anytime over the next ten days.  In fact, there is a good chance we won't see any more triple digit temperatures this year.

Tropical Weather Update
Activity in the tropics has increased over the past few days.  Tropical storm Fiona is currently located in the central tropical Atlantic, about 1295 miles west of the Cabo Verde Islands.  Maximum sustained winds are near 45 mph but some weakening is expected over the next couple of days as the system encounters dry air and some vertical wind shear. Fiona is forecast to weaken to a tropical depression over the weekend.  Fiona is moving to the west-northwest at 10 mph and this motion is forecast to continue for the next few days.  On this path, Fiona will be moving in the direction of Bermuda and poses no threat to the Gulf of Mexico.

 

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Of somewhat more concern is a strong tropical wave located in the eastern tropical Atlantic, about 600 miles southwest of the Cabo Verde Islands.  This system is producing a large area of disorganized clouds and shower activity.  Development, if any, during the next couple of days is expected to be slow as the system encounters a dry and stable air mass over the central tropical Atlantic.  After that time, environmental conditions are expected to become more conducive for development, and a tropical depression could form early next week.  National Hurricane Center forecasters are giving this system a 50 percent chance for development over the next 5 days.  This wave is embedded within the easterly trade winds and is forecast to move to the west at about 15 mph.  Should the system survive the dry air, it is forecast to reach a position over the eastern Caribbean Sea by about next Wednesday.  There is much uncertainty beyond this point, but it's not out of the question the system could bend northwest toward the Gulf of Mexico.  Stay tuned for more details on the progress of this strong tropical wave.

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Have a good weekend.

Bob

Widespread Rain and Thunderstorms Expected this Weekend and Monday
Thursday, August 18, 2016 6:23 PM


Scattered rain showers and thunderstorms developed across Central Texas Thursday, but areal coverage and rain amounts were less than what has occurred over the past few days.  The scattered showers will continue into Thursday evening but most of the activity should diminish shortly after sunset.

The trough of low pressure responsible for generating the waves of rain and thunderstorms since last Saturday is finally pushing off to the northeast.  However, a very moist atmosphere remains in place and will likely continue across Central and South Texas Friday and through the weekend.  This moisture, combined with warming temperatures, will cause the development of scattered rain showers and thunderstorms across the region Friday and Friday night.  Without a strong trigger in place, the probability for rain at any given location will be near 30 percent.  Rain amounts Friday will average around a quarter inch, with isolated totals to around 1 inch.  Do note that rainfall is forecast to be a little heavier and more widespread across the northern Hill Country and the Concho Valley regions where a disturbance in the upper atmosphere moves northeast out of the Big Bend region.  Totals to around an inch will be possible across this area.  Most areas should see a mostly cloudy to occasionally partly cloudy sky.  Expect a high temperature near 88-90 degrees.

After a short break from the rain, additional rain and thunderstorms are forecast beginning Saturday when another large trough of low pressure tracks east across the southern Plains states.  Atmospheric lift from the trough is expected to kick off a large area of rain and thunderstorms across the Hill Country Saturday morning, with the activity spreading east across Central Texas and the middle Texas coast Saturday afternoon and evening.  With abundant moisture being drawn in from the Gulf and Pacific, locally heavy rain will be possible.  A good chance for rain and thunderstorms is forecast Saturday night, continuing through Monday morning as the trough slowly tracks to the east.

Friday's rainfall forecasts indicate the heaviest rain and highest totals this weekend will likely occur across the Hill Country, with somewhat lower totals across the coastal plains.  The forecasts call for totals of 2-4 inches across the Hill Country, around 1-2 inches across Central Texas and less than an inch across the middle Texas coast.

NWS rainfall forecast for the period from 7 pm Thursday through 7 pm Tuesday:
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With the ground still very wet from recent rains, additional rains over the weekend will quickly runoff and could quickly cause flash flooding.  I urge everyone to keep up with weather developments and the latest forecasts.

The chance for rain is forecast to decrease Tuesday as the trough exits the region and moisture levels decrease.  Partly cloudy and generally dry weather is expected next Wednesday through Friday as a weak ridge of high pressure builds back across Texas.  High temperatures are forecast to warm back to the low 90s the second half of next week.  Long-range forecasts are hinting that another trough of low pressure in the upper atmosphere will push south into the Plains states next weekend and this could bring another chance for rain to our region the last few days of August.  No triple-digit temperatures are forecast over the next 10 days.

Tropical Atlantic Becoming Active
We are entering the most active part of the hurricane season and right on cue, the tropical Atlantic is starting to come alive.

Tropical storm Fiona is churning across the central tropical Atlantic, centered about 1145 miles west of the Cabo Verde, Islands.  Fiona is moving to the northwest at about 10 mph and this general motion should continue for the next couple of days.  Maximum sustained winds are near 45 mph and some slow strengthening is possible over the next day or two.  As of now, Fiona poses no threat to the Gulf of Mexico.

FMA.png                                                                                  NOAA-NASA GOES Project

A strong tropical wave moved off coast of Africa a couple of days ago and this system is something we'll need to watch over the next several days.  As of late Thursday afternoon, the wave was located about 300 miles southwest of the Cabo Verde Islands, producing widespread cloudiness and disorganized shower activity.  Environmental conditions are forecast to be conducive for gradual development of this disturbance over the next several days as it moves westward at about 15 mph.  National Hurricane Center forecasters are giving this system a 20 percent chance for development over the next 5 days.

It is interesting to note that NHC's 5-day forecast calls for the system to track generally to the west over the next few days, arriving at a position just east of the Lesser Antilles around next Tuesday.  Depending on how well the wave survives its journey across the Atlantic, it could track into the Gulf of Mexico during the latter half of next week.  Stay tuned for more details on this system over the next few days.

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Another tropical wave is forecast to move off of the coast of Africa on Saturday.  NHC forecasters believe slow development of this system will be possible as the wave moves generally westward through a marginally favorable environment.

Bob

Tropical Storm Fiona Develops in the Central Tropical Atlantic Ocean.
Wednesday, August 17, 2016 5:11 PM

Satellite observations Wednesday afternoon indicated tropical depression Six has acquired a central dense overcast and has made the transition to a tropical storm.  As a result, forecasters at the National Hurricane Center upgraded the system to tropical storm Fiona.  As of late Wednesday afternoon, Fiona was located over the central tropical Atlantic, roughly 920 miles west of the Cabo Verde Islands.  Fiona was moving to the northwest at about 16 mph.  A motion toward the northwest or west-northwest with some decrease in forward speed is expected over the next couple of days.

analog.png                                                                                                      NOAA-NASA GOES Project

Maximum sustained winds have increased to 40 mph and some slow strengthening is forecast during the next couple of days.  Fiona is being steered to the northwest by a large ridge of high pressure centered over the central Atlantic.   Forecast solutions indicate a general northwesterly motion over the open Atlantic in the direction of Bermuda should continue for the next several days.  On this path, Fiona poses little threat to the Gulf of Mexico.

Here is a look at the National Hurricane Center's 5-Day forecast track from late Wednesday afternoon:

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Forecasters are also monitoring a strong tropical wave that is forecast to move off the coast of Africa on Saturday.  Environmental conditions are expected to be somewhat conducive for slow development through early next week while the system moves generally westward and passes near the Cabo Verde Islands over the weekend.  NHC forecasters are giving this system a 20 percent chance for tropical development over the next 5 days.

Bob

Scattered Rain Showers Lingering into Thursday. Just a Slight Chance for Rain Friday.
Wednesday, August 17, 2016 2:06 PM

An wet and unsettled pattern continues across Central Texas.  Early this afternoon, weather radar showed scattered rain showers increasing in areal coverage across the region.  The most concentrated area of rain was located along and to the east of Interestate 35.  Some locations have already recorded over an inch of rain since noon.   All of the rain activity has been moving to the north-northeast at about 15 mph.

Today's analysis indicates the atmosphere over the region is still extremely moist.  In addition, a weak trough of low pressure in the upper atmosphere stretches from Central Texas to the Great Lakes states.  It's this trough that is helping to initiate the showers and thunderstorms.  With both of these factors still in place, a fairly widespread coverage of rain showers and isolated thunderstorms is forecast this afternoon, continuing through this evening.  Some of the rain may be heavy, producing totals of more than an inch in a short period of time.  In general, today's rain is forecast to average between 0.5 and 1 inch, with isolated totals of 3-4 inches possible.  The probability for rain will be near 70 percent.  With the ground extremely wet from recent rains, this additional rain will quickly runoff and may lead to flash flooding.  Because of this, the National Weather Service has posted a Flash Flood Watch for the region until 7 pm.  Scattered rain showers do look to continue this evening, with most of the activity decreasing after 10 pm.

The chance for rain is forecast to decrease some on Thursday as the trough slowly exits our region.  However, the atmosphere is expected to remain quite moist.  As a result, I do expect the development of scattered rain showers and isolated thunderstorms.  However, the rainfall coverage shouldn't be a great as what we are seeing today.  The probability for rain will be near 40 percent and rain amounts should average between 0.25 and 0.5 inch.  We will also begin to see some scattered sunshine, so the temperature should be warmer; rising upper 80s.

Today's forecast data indicates the atmosphere will begin to dry out Thursday night and remain fairly dry through Saturday.  Only a slight chance for rain is forecast through the period and rain amounts should only average around a quarter inch.  High temperatures both days should be near 90 degrees.

An increasing chance for rain and thunderstorms is forecast Saturday night, continuing through Monday when a weak cold front pushes into the region out of the southern Plains states.  A widespread coverage of rain is forecast through the period.  As of now, rain amounts are forecast to average between 1 and 2 inches.  With the ground still wet, this could bring back the threat for flash flooding.  High temperatures Sunday and Monday are forecast to be in the mid and upper 80s.

The chance for rain is expected to decrease next Tuesday, with just a slight chance for rain expected for the remainder of the week.  High temperatures are forecast to return to the low 90s by the middle of next week.

A Tropical Depression has Formed in the Eastern Atlantic
Early this morning, a strong tropical wave located over the far eastern Atlantic strengthened into a tropical depression.  At midday, the depression was centered about 840 miles west of the Cabo Verde Islands, moving to the west-northwest at 15 mph.  This general motion and a decrease in forward speed is expected during the next couple of days.

 

WO.png                                                                                                   NOAA-NASA GOES Project

 

Maximum sustained winds are near 35 mph and conditions appear favorable for strengthening.  The depression is forecast to become a tropical storm later today.  National Hurricane Center forecasters call for the system to move northwest into the open Atlantic over the next 5 days.  With this type of motion, the depression is expected to bypass the Gulf of Mexico and remain over the Atlantic Ocean.


 NHC 5-Day Tropical Cyclone Forecast

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Bob

The Rainy Pattern Will Continue into Thursday. More Rain Expected this Weekend.
Tuesday, August 16, 2016 5:55 PM

A wet and unsettled weather pattern remains in place across the Hill Country and Central Texas. This unsettled pattern is the result of a trough of low pressure in the upper atmosphere that stretches from the northern Plains states to the Big Bend region of Texas.  The trough is causing an unstable atmosphere over the region.  Meanwhile, circulation around a ridge of high pressure located over the southeastern US is helping steer a very moist air mass off the Gulf of Mexico into Texas.  This combination has produced waves of moderate to occasionally heavy rain showers.

On Tuesday, the rain at times was moderate to heavy in intensity and produced locally heavy rain at many locations.  Totals of 3 to 5 inches were observed across the eastern Hill Country and parts of Central Texas as well as the middle Texas coast.

Tuesday's forecast data indicated the trough of low pressure should hold in place across Central Texas through Wednesday then lift to the north-northeast Wednesday night into Thursday.  With that in mind, periods of rain showers and thunderstorms will likely continue across the region Tuesday night through Wednesday.  Some of the rain may at times be locally heavy.  With the ground very wet, any additional rain will quickly runoff, possibly leading to flash flooding.  As a result, the National Weather Service has extended the Flash Flood Watch until 7 pm Wednesday evening.  Rain amounts Wednesday are forecast to average between 0.5 and 1 inch but isolated totals of 3 to 4 inches will be possible.  Wednesday's high temperature will generally be in the low 80s.

The chance for widespread, heavy rain is forecast to decrease Wednesday night into Thursday. However, scattered rain showers and isolated thunderstorms will still be possible due to lingering deep tropical moisture.  The probability for rain will be near 40 percent and rain amounts should average less than a half inch.  Thursday's sky is forecast to be partly to mostly cloudy. Expect a high temperature in the mid 80s.  Just a slight chance for rain is forecast Friday as moisture levels decrease further.  Expect a partly cloudy sky and a high temperature in the upper 80s.

Looking ahead to the weekend, scattered rain showers and thunderstorms are forecast Saturday in advance of a cold front pushing south out of the Plains states.  The probability for rain will be near 30 percent.  Spotty totals to around a half inch are forecast.  Forecast solutions indicate that weak cold front across North Texas will push south into Central Texas Sunday.  With abundant moisture in place, widespread rain showers and thunderstorms are forecast Sunday into Monday.  Expect totals of 1-2 inches.  High temperatures will generally be in the mid 80s.

Weather conditions next Tuesday through Friday are forecast to be partly cloudy and generally dry as a weak ridge of high pressure builds over Texas.  Daily high temperatures are forecast to be near 88-90 degrees with low temperatures in the mid 70s.

Bob

Unsettled Pattern Continues; Rain Totals are Increasing.
Tuesday, August 16, 2016 12:03 PM

Heavy rains have fallen across parts of Central Texas and the Hill Country since Saturday and the totals are really beginning to add up.

Here is a look at estimated rain totals falling between 10 am Saturday and 10 am Tuesday. Note that most areas have seen between 1.5 and 4 inches but much higher totals have occurred at several locations.  I have circled some the highest totals.

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Much of northwestern Travis, western Williamson and southern Burnet Counties have seen between 6 and 8 inches as of noon.  Within this area, LCRA's Hydromet gauge located near Lakeway has recorded 10.77 inches since early Saturday.  

Central Bastrop County has also seen between 6 and 8 inches of rain.  An LCRA Hydromet gauge located along Cedar Creek, below Bastrop has recorded 8.09 inches as of noon.

The southern half of Wharton County, northwestern Matagorda County and northeastern Jackson County have also seen totals between 6 and 8 inches.  An LCRA Hydromet gauge near Lane City, in southern Wharton County, has measured 8.18 inches as of noon.

Totals across the Hill Country, west of a line stretching from about San Saba to Kerrville, have so far generally been less than a half inch.
 

Possible Tropical Depression Developing in the Eastern Atlantic
Satellite images Tuesday morning showed a large area of cloudiness and thunderstorms associated with a tropical wave centered about 500 miles west-southwest of the Cabo Verde Islands.  According to forecasters at the National Hurricane Center, this system is gradually becoming better organized and environmental conditions appear to be favorable for a tropical depression to form during the next couple of days.

Tom2.png                                                                                                         NOAA-NASA GOES Project

The system is forecast to move toward the west-northwest and then northwest toward the open waters of the central Atlantic.  NHC forecasters are giving this system an 80 percent chance for tropical development over the next 5 days.  The system poses no threat to the Gulf of Mexico.

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Bob
 
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