Thursday, July 22, 2010

Rain chances are diminishing


I haven't written any new weather blogs in a couple of weeks because there hasn't been much to talk about. July is generally a dry month and this one is living up to its reputation, except for the abundance of humidity!

This afternoon, the second of 3 tropical waves is moving into South Texas, where they don't need the extra rain. So far, San Antonio has been limited to a few short lived "random poppers", which have avoided my backyard like the plague! After Saturday, our rain chances quickly evaporate into the July sunshine and according to the latest info at 4pm, the Hurricane Center thinks the depression in the Caribbean will move into Louisiana, putting San Antonio on the dry and hot side of the system.

Fortunately, it's still early in the tropical season and hopefully some "light duty" storms will work their way into our area before we slip into another drought. Speaking of drought, it is looking as though La NiƱa is about to re-emerge in the Pacific again. If so, look for a dry and moderate winter for this upcoming season. For more info, click here.

Thursday, July 8, 2010


So far, the rains from tropical depression #2 have been pretty scant around my place in Helotes today. My 12 hr. storm total is 0.09.

NOAA is still thinking we will see some heavy rain overnight. Below is their latest thinking:

Here is a brief update and the outlook for tonight and Friday.
The remnants of TD#2 will continue to move west-northwest
just south of the U.S-Mexico border in the Lower Rio Grande
Valley tonight. Showers and thunderstorms will be widespread
across Texas. We expect quite a few locations to receive
1-2 inches of rain tonight through Friday afternoon, with
some locations receiving up to 6 inches, especially across the
Rio Grande Plains.

There may be minor flash flooding anywhere in our area where
1-2 inches of rain falls in a short period of time. The Flash Flood
Watch has been extended areawide through Noon on Friday.
However, the main threat will be continued major flooding along
the Rio Grande.

Our latest briefing graphic is attached, and of course, all the latest
weather and river information is available on our webpage at:
http://weather.gov/austin

-Jon Zeitler
NWS Austin/San Antonio

Tuesday, July 6, 2010

Flooding situation to the west


Here is the latest from NOAA on the horrific flooding going on to the west of San Antonio. Rainfall amounts in Mexico have been over 20 inches and more may be on the way.

NOAA 7-6-10:

It has been several days now since Alex made landfall...but the moisture over central and northern Mexico continues to produce huge rainfall totals in the mountains just west of Del Rio and the Rio Grande River. Additional rains are ongoing and will add to the already incredible totals that are being estimated by radar...upwards of 15-20+ inches in an area roughly the size of New Jersey. I have attached an image showing the estimated totals over the past 7 days. A Flash Flood Watch is in effect until at least 7 am Tuesday for Val Verde, Kinney, and Maverick Counties.

These large rainfall totals have led to major flooding along the Rio Grande from areas just northwest of Del Rio...down to Eagle Pass. The current heavy rain will produce even more runoff and we are expecting to have this flood event continue for the next several days at least. The inflow into Lake Amistad near Del Rio has led to an incredible 15 foot rise in the lake since Friday. As a result, large amounts of water will be released from the Dam and will lead to flooding downstream. The latest IBWC press release can be found here...
http://www.ibwc.state.gov/Files/Press_Release_070510.pdf

What worries me is that satellite images show a stream of moisture moving northward from
southern Mexico all the way north into the Big Bend...with no real end in sight. As long as we keep this moisture tap flowing north, the heavy rains will continue over the river basins that flow into the Rio Grande.

This is becoming a very dangerous situation. Another tropical wave near the Yucatan is forecast to approach northern Mexico or portions of Texas by mid to late week. This in fact could spread even more moisture into northern sections of Mexico and lead to even more rainfall.

Please monitor the latest forecasts, watches, and warnings by going to the National Weather Service website at www.srh.noaa.gov/ewx
River/lake
stages and flood forecasts can be found at the AHPS website :
http://water.weather.gov/ahps2/index.php?wfo=ewx
and a quick briefing webpage from the West Gulf River Forecast Center can be found at:
http://www.srh.noaa.gov/wgrfc/HMDmain.php

Paul Yura
National Weather Service Austin-San Antonio TX

Sunday, July 4, 2010

Happy 4th...update from NOAA


As some of you might know by now, the remains of Alex are causing heavy rain and flooding to the west of San Antonio. Here is the latest update (Noon-7-4-10) from NOAA:

Moisture from what was Hurricane Alex continues to produce widespread showers and thunderstorms over the mountains of Mexico and portions of West and Southwest Texas. Radar estimates that there has been 20+ inches of rain in a large area to the west and southwest of Del Rio over the last several days. Most of this area drains into the Rio Grande and has led to flooding along the River in spots and some of its tributaries. More recently in the past 24 hours, more of this moisture has moved north and is affecting the western 2/3rds of Val Verde county where currently flash flooding is occurring mainly west and northwest of Del Rio. A Flash Flood Watch is in effect for Val Verde county until Monday morning as several more inches of rain are possible across this area of Val Verde County. People and residents, as well as holiday travelers, campers, etc need to be aware that this is a dangerous situation across this area of Southwest Texas and everybody needs to take appropria
te precautions to stay out of harms way. Camping in and near creeks, rivers, and streams during this time is very dangerous and should be avoided.

As the rain continues across this area...we will see an increasing threat for significant flooding along the Rio Grande over the next several days....this includes areas of Val Verde, Kinney, and Maverick counties. I have attached the latest graphic from the West Gulf River Forecast Center showing this threat area.

Across other areas of South Central Texas today and Monday...scattered afternoon showers and thunderstorms are possible especially in the afternoon hours. It shouldnt be enough to cancel plans, but everybody should be prepared for a passing shower/tstorm. Brief heavy downpours are possible.

Please keep updated to the latest Flash Flood Watches, Warnings, and River Flood Warnings by going to the National Weather Service website at www.srh.noaa.gov/ewx
and to the AHPS webpage at http://water.weather.gov/ahps2/index.php?wfo=ewx

Paul Yura
National Weather Service Austin-San Antonio TX

Friday, July 2, 2010

Latest from NOAA 2pm-7-2


Looking at radar at 2:20 pm., it is starting to fill in with lots of red as tropical "poppers" make their way toward San Antonio. With an abundance of moisture in the form of ridiculously high dew points, some heavy rain appears to be eminent. My storm total in Helotes so far is 1.5 inches.

Here is the latest from NOAA:

The rich tropical atmosphere is very apparent as soon as you step outside. This is leading to the widespread showers and thunderstorms that are moving across most areas of South Central Texas early this afternoon. A Flash Flood Watch remains in effect until 7 pm tonight...and will likely be extended until 7 am Saturday. Only minor flood issues are ongoing across some areas of South Central Texas as the storms are moving fairly quick at 30 mph and rain rates have averaged under 1 inch per hour. But as the afternoon progresses and some areas get additional showers/storms to train over the same areas, the threat for heavier rain and flooding will increase. Widespread rains of 1-2 inches are possible with isolated totals near 4 to 5 inches.

There will be a lot of people on the road later today trying to get a jump start on their holiday weekend...so please be careful and Turn Around Dont Drown. Dont risk driving through the flooded roadways and low water crossings. Many will be staying at camp grounds next to or along creeks, streams, or rivers. These areas are particularly dangerous during these heavy rain events. And as we saw several weeks ago with the flood in New Braunfels and in Arkansas...flooding at night can be particularly deadly. Stay tuned to NOAA Weather Radio and the National Weather Service website for the latest watches, warnings, and advisories.... www.srh.noaa.gov/ewx

The heavy rain from Alex over northern Mexico is draining into the Rio Grande and is leading to some moderate flooding just above Lake Amistad. Areas near and along the Rio Grande should pay particular attention to the weather and forecasts of the Rio Grande as well as other areas rivers and creeks. They can be monitored from the following website...http://water.weather.gov/ahps2/index.php?wfo=ewx

As the holiday weekend quickly approaches...scattered showers and thunderstorms with locally heavy downpours will occur again on Saturday, with roughly a 40-50 percent chance for rain mainly in the morning through evening hours. On the 4th of July, will still carry a 30-40% chance of rain...with chances dropping to near 20% by the time of fireworks Sunday evening. There is fairly high confidence that the overall coverage of rain activity will be much less on Sunday afternoon and evening.

Be careful this holiday weekend, the wet conditions will make driving hazardous and rivers/creeks will be flowing quickly.

Paul Yura
National Weather Service Austin San Antonio TX
--

Thursday, July 1, 2010

Latest from NOAA


I've gotten 3/4 of an inch of rain in my backyard today...hoping for more. According to the latest long range forecasts, it looks like a good chance for wetter than normal conditions for the next two weeks. Here is the latest from NOAA:

Bands of light to moderate rain continue this afternoon across much of South Central Texas. Overall rain totals across most of the area have generally been less than one half inch...with higher totals over 1 inch south and east of San Antonio. The threat for locally heavy rain will continue tonight and into Friday as rich tropical moisture continues to move into the area. For this reason the Flash Flood Watch has been extended for most of South Central Texas until 7 am Friday morning. I have attached the graphic of the latest rainfall forecast. Over the next 48 hours...some areas south and west of Austin may receive an additional 2 to 3 inches of rain...isolated totals possible near 4 inches. There remains a low to moderate flood threat along the Rio Grande as moisture from Alex produces heavy rain over Northern Mexico and is forecast to track north into West Texas over the weekend. Northern areas of South Central Texas will likely receive less rain...averaging 1-2 inches.

These bands of showers and thunderstorms can and will produce torrential downpours at times...with hourly rain rates of 1 to 2 inches. This will cause ponding of water on roads, localized flooding in urban areas, and some creeks and streams may fill or even overflow. Drivers need to be aware of possible flooded low water crossings.

Rain chances will slowly decrease through the holiday weekend...but with daytime heating and plenty of tropical moisture in place, scattered showers and thunderstorms will remain in the forecast. The scattered nature of the storms however should mean that there would be only minor interruptions to outdoor activities. Still, the weekend storms may still produce 1-2 inches of rain in some isolated spots. Rain chances go down to around 20% by Sunday night.

Keep informed of the latest weather information by going to the National Weather Service website at www.srh.noaa.gov/ewx

Paul Yura
National Weather Service Austin-San Antonio TX