Texas Spring-2015

[Shoshana]

We keep getting warned in Austin that we could see some hazardous weather. And then we get nothing or a few raindrops. At least where we are.

I'm prepared but hoping we get rain and nothing else here today and tomorrow. I know forecasts are supposedly getting better but 2015 has been very weird.

[weatherdude1108]

We keep getting warned in Austin that we could see some hazardous weather. And then we get nothing or a few raindrops. At least where we are.

I'm prepared but hoping we get rain and nothing else here today and tomorrow. I know forecasts are supposedly getting better but 2015 has been very weird.

I agree! It has been very weird. I'm pulling for some good rains. I don't want any of the other stuff. It looks like reports so far have had really heavy rains and flooding out to the west, with some reports of quarter size hail (radar indicated) from what I have seen. Looks like they are slow movers, which may help to cool it down to stabilize a little and lower the severe threat I would think/hope. We need the rain more than anything else.

[Brent]

Here we go again... HRRR has been consistent with this the last few runs lol. How will it fail today?

[gboudx]

Based on current radar trends, the HRRR looks spot on.

[Brent]

Based on current radar trends, the HRRR looks spot on.

That it does... but I'm still expecting the inevitable avoid DFW thing.

[gboudx]

Update from jeff. Keep in mind these are typically specific to SETX.

Severe Thunderstorm Watch # 67 issued until 700pm for all of N/C and SW TX.

Approaching strong upper level disturbance on southern flank of a large upper level low over the SW US resulting in the rapid formation of numerous strong to severe thunderstorms from Childress to San Angelo to Laredo. Activity on the southern part of this line is showing some supercell characteristics south of Junction, TX and east of Laredo, TX.

Downstream air mass over SC/S TX is extremely unstable with CAPE values over 3000 J/kg and little to no capping. Weak diffuse low level boundary is laying along a line from offshore of Galveston to Port O Connor and then inland over SC TX toward Cotulla, TX. Air mass over SE TX is still in recovery mode, but surface heating under nearly sunny skies is pushing surface temperatures toward 80 degrees already and puffy cumulus are starting to develop suggesting instability is building. Thermo and severe weather parameters and fairly impressive for this afternoon and expect another round of widespread strong to severe thunderstorms as the strong Baja disturbance ejects across SC TX and strong 200mb divergence increases creating sustained lift.

Flooding rainfall, damaging winds to 60mph, and large hail are the main threats. Low level winds are currently veering to the SE and S as the meso high edges east which is reducing the near surface shear over the region which should help mitigate the tornado threat.

Quick flash flood decision matrix certainly supports the ongoing flood watch with 3 to 6 hr flash flood guidance now very low across the region. Looking at only 1-2 inches to start causing significant run-off problems and with high PW air mass of 1.8 inches incoming from the SW, we could easily see those rates in an hour or less which will quickly place locations into a flash flood mode. Really worried about Harris, Chambers, and Liberty Counties where rainfall was greatest yesterday and watersheds are still trying to drain overnight run-off. It is unlikely that the run-off will be drained out before the next round arrives which only serves to increase the flooding threat. WPC has place the central portions of SE TX under a moderate risk of excessive rainfall and flooding.

Residents across SE TX are urged to remain aware of the developing weather situation this afternoon/evening and be prepared to act quickly if severe weather or flooding impacts your location.

Note: Additional weather watches will almost certainly be required E of weather watch 67 later this afternoon.

Edit to add a recent update from jeff:

SPC monitoring area for possible extension or new issuance of weather watch downstream of box 67.

Air mass is becoming very unstable over SC TX into the Matagorda Bay region with increasing and intensifying storm structures over the Rio Grande plains. Surface observations show a dewpoint of 74 at Victoria with an air temperature in the lower 80’s. Parameters are in place for an increase in the severe wind and hail threat over the next 2-4 hours as this activity moves toward the Corpus, Victoria, Matagorda Bay region.

Very large hail to 2 inches in diameter and potential damaging wind gusts to 70mph will be possible with this activity.

Additional cells may begin to develop within the next 1-2 hours along returning outflow/warm front boundary near the coast where visible satellite images shows enhancement of vertical cumulus formations. These storms may also go severe and be extremely slow moving producing excessive flooding rainfall rates. CRP radar appears to be showing the start of development SW of Victoria along US 59.

[Portastorm]

BTW, for those skeptics who doubt us Austin area and DFW area precip gripers ... take a look at the precip map for the last 30 days ... clearly the I-35 corridor from Austin north has gotten stiffed by rainfall.

[gboudx]

Let's hope the Texas Tech model is not correct again today. From Steve McCauley posted 6 hours ago:

OK...let's try this again. Another round of thunderstorms will try to fire out west and attempt to sweep north Texas. This event looks a little more promising that yesterday since there will be a little more upper-level support for this storm cluster, meaning there "should"be some subtle RISING AIR over the Metroplex by late afternoon which "should" allow this storm line to survive.

However, true to form, the Texas Tech Model model once again develops a HUGE cluster of severe storms with flooding rains well to our south and southeast and blankets north Texas with widespread SINKING AIR which crushes the storms depicted in this graphic as they approach.

Let's see how this plays out. I don't have time to run the SM on this, but updates will follow when I get back from class!

[Brent]

Let's hope the Texas Tech model is not correct again today. From Steve McCauley posted 6 hours ago:

OK...let's try this again. Another round of thunderstorms will try to fire out west and attempt to sweep north Texas. This event looks a little more promising that yesterday since there will be a little more upper-level support for this storm cluster, meaning there "should"be some subtle RISING AIR over the Metroplex by late afternoon which "should" allow this storm line to survive.

However, true to form, the Texas Tech Model model once again develops a HUGE cluster of severe storms with flooding rains well to our south and southeast and blankets north Texas with widespread SINKING AIR which crushes the storms depicted in this graphic as they approach.

Let's see how this plays out. I don't have time to run the SM on this, but updates will follow when I get back from class!

I was also just noticing it seems like it's trying to pull north out by Abilene, with a gap forming south of there DFW can fit into.

[weatherdude1108]

Just now starting to pitter patter here at work. Looks like it has been primarily a heavy rain and wind threat to our west and south. Let's see if the Austin bubble continues.
"You can do it, you can do it, you can do it...!"

[Brent]

[weatherdude1108]

I woke up this morning anxious of a potential 2-inch hail and tornadic threat. Now I am wondering if it will rain enough to measure in the gauge, and the EWX is questioning whether or not storms form at all tomorrow in one sentence. I guess I need to move somewhere that it rains, which is apparently everywhere around Austin and the Highland Lakes areas (and the DFW area). Meanwhile, the soil cracks continue to widen, and the lake levels continue their downward plunge (in Central Texas).

Just frustrated and venting, that's all. Maybe it will rain substantially soon, and all of this chatter of no rain will be just chatter.

000
FXUS64 KEWX 172018
AFDEWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
318 PM CDT FRI APR 17 2015

.SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)...
UPPER AIR ANALYSIS THIS MORNING SHOWED A LOW OVER THE FOUR CORNERS
REGION WITH SOUTHWESTERLY FLOW ACROSS TEXAS. A 95 KT JET STREAK AT
250MB WAS NOSING INTO SOUTH TEXAS. AT THE SURFACE A WEAK COLD
FRONT STRETCHED FROM NEAR BIG SPRING TO PANDALE AND THEN BACK TO
NEAR THE BIG BEND. OVER TO THE EAST THERE WAS A STATIONARY FRONT
OVER THE COASTAL PLAINS FROM NEAR HOUSTON TO VICTORIA. WINDS
ACROSS OUR CWA WERE FROM THE EAST TO SOUTHEAST AND THE LOW LEVELS
ARE VERY MOIST WITH DEW POINT TEMPERATURES IN THE MID 60S TO LOW
70S. AREA SOUNDINGS THIS MORNING SHOWED AN UNCAPPED ATMOSPHERE
WITH 2000-3000 J/KG CAPE WITH 30 TO 40 KTS OF VERTICAL WIND SHEAR.
CONVECTION WILL BE ONGOING IN THE FIRST PERIOD. A SEVERE
THUNDERSTORM WATCH IS IN EFFECT UNTIL 7PM FOR THE COUNTIES FROM
WILLIAMSON TO KARNES AND WEST. WITH MODEST SHEAR AND HIGH CAPE
STORMS MAY FORM INTO A COUPLE OF CLUSTERS ONE ALONG THE COLD
FRONT IN THE NORTH AND ANOTHER ALONG THE WARM FRONT IN THE SOUTH. OVER
THE EASTERN COUNTIES A FLASH FLOOD WATCH REMAINS IN EFFECT. THIS
AREA RECEIVED 3 TO 5 INCHES OF RAIN THURSDAY AND STORMS WILL MOVE
ALONG THE WARM FRONT PRODUCING MORE LOCALLY HEAVY RAIN. ANOTHER 1
TO 2 INCHES WITH ISOLATED AMOUNTS OF 4 ARE POSSIBLE. EXPECTING
CONVECTION TO WEAKEN OVERNIGHT...BUT THUNDERSTORMS ARE STILL
POSSIBLE. THE UPPER LOW WILL SLOWLY MOVE TO THE EAST AND OPEN TO A
WAVE. INSTABILITY AND SHEAR WILL STILL BE FAVORABLE FOR SEVERE
THUNDERSTORMS. [b]SO THE QUESTION TOMORROW MAY BE WHETHER OR NOT
STORMS FORM. [/b]IF THEY DO...THERE WILL LIKELY BE SOME SEVERE. SPC
HAS US IN A SLIGHT RISK. BEST CHANCES FOR STORMS WILL BE FROM THE
WEST OFF THE MOUNTAINS OF MEXICO. MOST LIKELY THREAT WILL BE LARGE
HAIL AND DAMAGING WINDS.

&&

.LONG TERM (SUNDAY THROUGH FRIDAY)...
THE UPPER TROUGH WILL MOVE TO THE EAST SUNDAY. A COLD FRONT WILL
MOVE THROUGH OUR CWA. UPPER FLOW ACROSS TEXAS WILL BECOME ZONAL
FOR SUNDAY AND MONDAY. A WEAK RIDGE WILL MOVE IN FROM THE WEST
TUESDAY AND BUILD VERY SLOWLY THROUGH THE REST OF THE PERIOD.
RETURN FLOW FROM THE GULF WILL BEGIN TUESDAY AND THIS MOISTURE
WILL GIVE US CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY
THROUGH THE END OF THE PERIOD.

[gboudx]

weatherdude, the radar trend sure looks like your friend for ATX area. Huge shield riding up 35, and it looks like good storms west of Austin which is where I think most of the watershed is for your lakes.

[Brent]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
310 PM CDT FRI APR 17 2015

.DISCUSSION...
A SHORTWAVE TROUGH AXIS IS NOW MOVING THROUGH TEXAS AND UPPER
LEVEL LIFT IS INCREASING OVER THE REGION. AS THIS LIFT INTERACTS
WITH AN AXIS OF UNCAPPED INSTABILITY FROM ROUGHLY WICHITA FALLS TO
ABILENE AND SOUTH INTO THE LOWER RIO GRANDE VALLEY...SCATTERED TO
NUMEROUS THUNDERSTORMS HAVE DEVELOPED. WHILE STORM MOTION HAS BEEN
GENERALLY NORTHWARD...IT APPEARS THAT COLD POOLS ARE BEGINNING TO
ORGANIZE BENEATH THE STRONGER CLUSTERS OF STORMS WITH MORE
EASTWARD MOTIONS NOTED WITH THE CELLS IN THE NW CWA NEAR
GRAHAM...AS WELL AS THE STORM SEGMENTS WEST AND ALSO SOUTH OF SAN
ANTONIO. AS THE COLD POOLS CONTINUE TO DEVELOP... THE EASTWARD
MOTION WILL ACCELERATE. POPS WILL BE HIGHEST THIS EVENING FOR THE
NORTHERN PART OF THE CWA AND ALSO THE SOUTHERN PART OF THE CWA.
THIS IS WHERE THE SMALL LINE SEGMENTS OR CLUSTERS OF STORMS ARE
MOST LIKELY TO TRACK NEAR. THERE IS A CHANCE A GAP IN THE ACTIVITY
WILL OCCUR RIGHT ACROSS THE CENTRAL CWA PRIMARILY DUE TO THE STORM
CLUSTERS IN SOUTH CENTRAL TEXAS INCREASING IN STRENGTH AND
INTERCEPTING THE BEST MOISTURE AND INSTABILITY ACROSS OUR AREA.
MANY LOCATIONS WILL JUST EXPERIENCE LIGHT RAIN FROM ANVIL BLOW OFF
BUT WHERE STORMS DO TRACK...WELL OVER 2 INCHES OF RAIN IS POSSIBLE.
THIS ACTIVITY WILL TRACK MOSTLY EAST OF CWA AFTER MIDNIGHT.

[dhweather]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
310 PM CDT FRI APR 17 2015

.DISCUSSION...
A SHORTWAVE TROUGH AXIS IS NOW MOVING THROUGH TEXAS AND UPPER
LEVEL LIFT IS INCREASING OVER THE REGION. AS THIS LIFT INTERACTS
WITH AN AXIS OF UNCAPPED INSTABILITY FROM ROUGHLY WICHITA FALLS TO
ABILENE AND SOUTH INTO THE LOWER RIO GRANDE VALLEY...SCATTERED TO
NUMEROUS THUNDERSTORMS HAVE DEVELOPED. WHILE STORM MOTION HAS BEEN
GENERALLY NORTHWARD...IT APPEARS THAT COLD POOLS ARE BEGINNING TO
ORGANIZE BENEATH THE STRONGER CLUSTERS OF STORMS WITH MORE
EASTWARD MOTIONS NOTED WITH THE CELLS IN THE NW CWA NEAR
GRAHAM...AS WELL AS THE STORM SEGMENTS WEST AND ALSO SOUTH OF SAN
ANTONIO. AS THE COLD POOLS CONTINUE TO DEVELOP... THE EASTWARD
MOTION WILL ACCELERATE. POPS WILL BE HIGHEST THIS EVENING FOR THE
NORTHERN PART OF THE CWA AND ALSO THE SOUTHERN PART OF THE CWA.
THIS IS WHERE THE SMALL LINE SEGMENTS OR CLUSTERS OF STORMS ARE
MOST LIKELY TO TRACK NEAR. THERE IS A CHANCE A GAP IN THE ACTIVITY
WILL OCCUR RIGHT ACROSS THE CENTRAL CWA PRIMARILY DUE TO THE STORM
CLUSTERS IN SOUTH CENTRAL TEXAS INCREASING IN STRENGTH AND
INTERCEPTING THE BEST MOISTURE AND INSTABILITY ACROSS OUR AREA.
MANY LOCATIONS WILL JUST EXPERIENCE LIGHT RAIN FROM ANVIL BLOW OFF
BUT WHERE STORMS DO TRACK...WELL OVER 2 INCHES OF RAIN IS POSSIBLE.
THIS ACTIVITY WILL TRACK MOSTLY EAST OF CWA AFTER MIDNIGHT.

Of course.

[Brent]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
310 PM CDT FRI APR 17 2015

.DISCUSSION...
A SHORTWAVE TROUGH AXIS IS NOW MOVING THROUGH TEXAS AND UPPER
LEVEL LIFT IS INCREASING OVER THE REGION. AS THIS LIFT INTERACTS
WITH AN AXIS OF UNCAPPED INSTABILITY FROM ROUGHLY WICHITA FALLS TO
ABILENE AND SOUTH INTO THE LOWER RIO GRANDE VALLEY...SCATTERED TO
NUMEROUS THUNDERSTORMS HAVE DEVELOPED. WHILE STORM MOTION HAS BEEN
GENERALLY NORTHWARD...IT APPEARS THAT COLD POOLS ARE BEGINNING TO
ORGANIZE BENEATH THE STRONGER CLUSTERS OF STORMS WITH MORE
EASTWARD MOTIONS NOTED WITH THE CELLS IN THE NW CWA NEAR
GRAHAM...AS WELL AS THE STORM SEGMENTS WEST AND ALSO SOUTH OF SAN
ANTONIO. AS THE COLD POOLS CONTINUE TO DEVELOP... THE EASTWARD
MOTION WILL ACCELERATE. POPS WILL BE HIGHEST THIS EVENING FOR THE
NORTHERN PART OF THE CWA AND ALSO THE SOUTHERN PART OF THE CWA.
THIS IS WHERE THE SMALL LINE SEGMENTS OR CLUSTERS OF STORMS ARE
MOST LIKELY TO TRACK NEAR. THERE IS A CHANCE A GAP IN THE ACTIVITY
WILL OCCUR RIGHT ACROSS THE CENTRAL CWA PRIMARILY DUE TO THE STORM
CLUSTERS IN SOUTH CENTRAL TEXAS INCREASING IN STRENGTH AND
INTERCEPTING THE BEST MOISTURE AND INSTABILITY ACROSS OUR AREA.
MANY LOCATIONS WILL JUST EXPERIENCE LIGHT RAIN FROM ANVIL BLOW OFF
BUT WHERE STORMS DO TRACK...WELL OVER 2 INCHES OF RAIN IS POSSIBLE.
THIS ACTIVITY WILL TRACK MOSTLY EAST OF CWA AFTER MIDNIGHT.

Of course.

Radar looks good again... the line has solidified.

and Steve McCauley says the TTU model caved and has the line sweeping through the metro:

[dhweather]

I hope so Brent, but you know how it goes, these lines hit the metroplex and split.

[gboudx]

I hope it's not a case of the storms in SETX robbing inflow and causing these to die off. But looks like our friends in ATX are gonna get rain.

[Brent]

I hope so Brent, but you know how it goes, these lines hit the metroplex and split.

Yes I do know but it looks promising... it hasn't weakened yet. SVR warning just popped in Parker County

[Shoshana]

Thunder and rain here. Not much of either. I'll take any rain we get.