Texas Fall-2014

[South Texas Storms]

A widespread beneficial heavy rain event is likely across much of Texas this week. Tropical moisture from Hurricane Vance in the eastern Pacific Ocean is expected to combine with a storm system and cold front to produce heavy rainfall over the state mainly on Tuesday and Wednesday. Some places could receive over 3 inches of rain from this event. Bring it on!

Latest WPC 5-day rainfall total forecast:

[Tireman4]

Yep, this is a soaker....

[TheProfessor]

The GFS seems to be getting drier and drier for DFW

[somethingfunny]

The GFS seems to be getting drier and drier for DFW

The timing is off for Vance up here. We're still going to get rain from the cold front, but Vance won't be really hooking up with the subtropical jet until the front gets farther south into Texas.

[BrokenGlassRepublicn]

The GFS seems to be getting drier and drier for DFW

The timing is off for Vance up here. We're still going to get rain from the cold front, but Vance won't be really hooking up with the subtropical jet until the front gets farther south into Texas.

Lucy, you've got some 'splainin to do!

[Texas Snowman]

Glad to see that nearly all of the state (except NW Panhandle) will get in on the rain act this week. Hopefully North Texas sees some beneficial rains. And I especially hope some training and huge runoff totals set up on the watersheds of some of the central and southern lakes that are so exceptionally dry.

[gatorcane]

The Parallel GFS is showing some nice rainfall totals for most of Texas:

[weatherdude1108]

Just repeating what has already been stated lately on this thread. Just -- a
WONDERFUL short-term AND long-term forecast by Bob Rose written just after 12 noon today. Our soils in the hill country and central Texas are relatively dry, so it will take a while for the rain to run off into the rivers, lakes, and aquifers and make any kind of a drought dent. As the rains add up, those in urban areas and even those in rural low water areas should use common sense and take the advice of "Turn around, don't drown!"

http://www.lcra.org/water/river-and-wea ... ather.aspx

[cycloneye]

Plenty of moisture with the help of what will be left of Vance. From latest advisory discussion.

Moisture from Vance and its remnants should spread northeastward
across Mexico and into the south-central United States during the
next several days. This is likely to produce heavy rains over
portions of these areas through Thursday or Friday.

[weatherdude1108]

FXUS64 KEWX 032131
AFDEWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
331 PM CST MON NOV 3 2014

.SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
DEEP LAYER MOISTURE CONTINUES TO INCREASE ACROSS SOUTH CENTRAL TEXAS
AS EVIDENCED BY PWAT VALUES DOUBLING BETWEEN 02/12Z-03/12Z ON THE
DRT AND CRP SOUNDINGS. THIS INCREASE IN MOISTURE WILL LEAD TO
ISOLATED...LIGHT SHOWERS THROUGH THIS AFTERNOON. RAIN SHOWERS SHOULD
BECOME A LITTLE MORE WIDESPREAD TONIGHT AS THE LOW-LEVEL JET
INCREASES. WE EXPECT MAINLY SHOWERS...BUT CAN/T RULE OUT A FEW
THUNDERSTORMS GENERALLY NORTH OF A DEL RIO TO BURNET LINE. RAIN
CHANCES CONTINUE TO INCREASE ON TUESDAY AS AN UPPER LEVEL TROUGH
DROPS SOUTHWARD INTO NORTHERN MEXICO. RAIN CHANCES REMAIN HIGHEST
ACROSS THE SOUTHERN EDWARDS PLATEAU AND NORTHERN HILL COUNTRY ON
TUESDAY AS THE COLD FRONT MOVES IN LATE IN THE AFTERNOON OR EARLY IN
THE EVENING. BY THIS TIME...SOUTHERLY FLOW FROM THE GULF OF MEXICO
ALONG WITH MID AND UPPER LEVEL MOISTURE FROM TROPICAL SYSTEM VANCE
WILL DRIVE PRECIPITABLE WATER AMOUNTS GENERALLY ABOVE 1.5". DEEP
LAYER MOISTURE CONTINUES TO INCREASE TUESDAY EVENING AS THE COLD
FRONT MOVES SOUTHWARD. WITH PRECIPITABLE WATER VALUES PEAKING IN THE
1.75-NEAR 2" RANGE ACROSS THE EASTERN AND SOUTHWESTERN PORTIONS OF
SOUTH CENTRAL TEXAS...HEAVY RAINFALL IS EXPECTED. WITH THIS IN
MIND...WE HAVE OPTED TO ISSUE A FLASH FLOOD WATCH FOR AREAS ALONG
AND EAST OF INTERSTATE 35 AND FOR AREAS ALONG AND SOUTH OF U.S.
HIGHWAY 90. GIVEN THE MODELS LATEST TRENDS OF SLOWING THE UPPER
LEVEL TROUGH...WE WILL RUN THE FLASH FLOOD FROM MIDNIGHT WEDNESDAY
THROUGH NOON WEDNESDAY.

&&

.LONG TERM (WEDNESDAY THROUGH MONDAY)...
AS MENTIONED ABOVE...THE FORECAST MODELS ARE NOW TRENDING SLOWER
WITH THE UPPER LEVEL TROUGH. THIS WILL RESULT IN AN INCREASE IN
RAIN CHANCES ACROSS MOST AREAS ON WEDNESDAY. THE BETTER CHANCE
FOR RAIN ON WEDNESDAY WILL BE CONFINED TO AREAS GENERALLY
EAST/SOUTH OF A CARRIZO SPRINGS TO SAN ANTONIO TO HALLETTSVILLE
LINE. THIS AREA WILL CONTINUE TO REMAIN IN PROXIMITY TO HIGHER
MOISTURE LEVELS ALONG WITH FAVORABLE UPPER LEVEL JET DYNAMICS. WE
ARE STILL EXPECTING AVERAGE RAINFALL TOTALS OF 2 TO 4 INCHES WITH
ISOLATED TOTALS UP TO 7 INCHES. THE AXIS OF HEAVIER RAINFALL
TOTALS IS STILL UNCERTAIN...BUT TEND TO FAVOR A UVALDE TO SAN
ANTONIO TO GIDDINGS LINE. AS MENTIONED ABOVE...THE FLASH FLOOD
WATCH WILL RUN UNTIL NOON ON WEDNESDAY. WE STILL EXPECT RAINFALL
ACROSS MUCH OF SOUTH CENTRAL TEXAS IN THE AFTERNOON HOURS...BUT
THE FOCUS FOR HEAVY RAINFALL WILL SHIFT TO THE SOUTH AND EAST OF
OUR REGION. MOISTURE LEVELS DECREASE SIGNIFICANTLY ON THURSDAY...
BUT CAN/T RULE OUT A FEW LIGHT SHOWERS IN THE MORNING. WE/LL GO
WITH A DRY FORECAST BEGINNING FRIDAY AND CONTINUING INTO MONDAY OF
NEXT WEEK. WE DO EXPECT ANOTHER COLD FRONT WILL MOVE THROUGH THE
REGION ON SATURDAY. SOUTHERLY FLOW IN THE LOW-LEVELS RETURNS BY
LATE SUNDAY AND THIS WILL LEAD TO TEMPERATURES TRENDING UPWARD ON
MONDAY.

[weatherdude1108]

New Flash Flood Watch. I'm already not liking the placement of it. Heaviest potential too far east to benefit the Highland Lakes, as usual.

WGUS64 KEWX 032157
FFAEWX

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH 357 PM CST MON NOV 3 2014

...HEAVY RAINFALL AND FLASH FLOODING POSSIBLE ACROSS A GOOD
PORTION OF SOUTH CENTRAL TEXAS TUESDAY NIGHT THROUGH WEDNESDAY
MORNING...

.AN UPPER LEVEL STORM SYSTEM...COLD FRONT AND INCREASING
MOISTURE FROM THE GULF OF MEXICO AND MOISTURE FROM HURRICANE VANCE
WILL BRING LOCALLY HEAVY RAINFALL TO PORTIONS OF SOUTH CENTRAL
TEXAS LATE TUESDAY EVENING THROUGH WEDNESDAY MORNING. THE HEAVY
RAINFALL IS EXPECTED TO OCCUR GENERALLY ALONG AND EAST OF
INTERSTATE 35...AS WELL AS ALONG AND SOUTH OF U.S. HIGHWAY 90.
RAINFALL AMOUNTS ARE EXPECTED TO BE HIGHEST TUESDAY NIGHT THROUGH
WEDNESDAY MORNING AS A COLD FRONT MOVES THROUGH THE REGION.
RAINFALL AMOUNTS WILL BEGIN TO DECREASE BY WEDNESDAY AFTERNOON AS
THE FRONT MOVES SOUTH OF THE AREA. AVERAGE RAINFALL AMOUNTS OF 2
TO 4 INCHES WITH ISOLATED AMOUNTS UP TO 7 INCHES ARE POSSIBLE
ACROSS THE WATCH AREA.

FLASH FLOODING REMAINS POSSIBLE IN AREAS WHERE SEVERAL ROUNDS OF
HEAVY RAINFALL OCCUR OVER A SHORT PERIOD OF TIME. IN ADDITION TO
THE THREAT OF FLASH FLOODING...THESE HEAVY RAINS COULD PRODUCE
RAPID RISES IN AREA RIVERS...STREAMS AND NORMALLY DRY CREEKS.

TXC013-021-029-055-091-123-127-149-163-177-187-209-255-271-285-
287-323-325-453-463-491-493-507-041200-


ATASCOSA-BASTROP-BEXAR-CALDWELL-COMAL-DEWITT-DIMMIT-FAYETTE-FRIO-
GONZALES-GUADALUPE-HAYS-KARNES-KINNEY-LAVACA-LEE-MAVERICK-MEDINA-
TRAVIS-UVALDE-WILLIAMSON-WILSON-ZAVALA-
INCLUDING THE CITIES OF...PLEASANTON...BASTROP...SAN ANTONIO...
LOCKHART...NEW BRAUNFELS...CUERO...CARRIZO SPRINGS...LA GRANGE...
PEARSALL...GONZALES...SEGUIN...SAN MARCOS...KARNES CITY...
BRACKETTVILLE...HALLETTSVILLE...GIDDINGS...EAGLE PASS...HONDO...
AUSTIN...UVALDE...GEORGETOWN...FLORESVILLE...CRYSTAL CITY
357 PM CST MON NOV 3 2014

...FLASH FLOOD WATCH IN EFFECT FROM LATE TUESDAY NIGHT THROUGH
WEDNESDAY MORNING...

THE NATIONAL WEATHER SERVICE IN AUSTIN/SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WATCH FOR THE FOLLOWING COUNTIES IN SOUTH CENTRAL
TEXAS...ATASCOSA...BASTROP...BEXAR...CALDWELL...COMAL...
DEWITT...DIMMIT...FAYETTE...FRIO...GONZALES...GUADALUPE...
HAYS...KARNES...KINNEY...LAVACA...LEE...MAVERICK...MEDINA...
TRAVIS...UVALDE...WILLIAMSON...WILSON AND ZAVALA.

* FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING

* AVERAGE RAINFALL AMOUNTS OF 2 TO 4 INCHES...WITH ISOLATED
AMOUNTS UP TO 7 INCHES POSSIBLE ACROSS THE WATCH AREA.

* FLASH FLOODING OF LOW WATER CROSSINGS AND OTHER LOW LYING AND
NORMALLY FLOOD PRONE AREAS IS LIKELY DUE TO HEAVY RAINS.
NORMALLY DRY CREEKS AND AREA STREAMS MAY ALSO SEE RAPID RISES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS FLASH FLOODING IS POSSIBLE IN OR NEAR
THE WATCH AREA. IF YOU ARE IN THE WATCH AREA...PLAN NOW FOR WHAT
YOU WILL DO IF FLASH FLOODING DEVELOPS. STAY INFORMED AND BE
READY TO ACT IF YOU SEE FLOODING OR IF A FLASH FLOOD WARNING IS
ISSUED.

&&

[South Texas Storms]

It's still too early to tell where the heaviest rain will fall during this event. I do think the Highland lakes have a good chance of receiving 1-3 inches of rain by Wednesday night though.

[Ntxw]

Lets wait until after the rain falls to make a call on go or bust guys. It is November after all and getting over 1+ inch f rain gets tougher and tougher in the cold season. Take what we can get, 1-3 inches is good for this time of year given dewpoints are not what they are earlier in the fall and summer.

[weatherdude1108]

True, yeah. Sorry guys. I'm being impatient again. I sometimes have to be reminded that it is not easy to "quick fix" a long-term multi-year drought. Medina Lake is probably in the worst shape out of all the lakes in Texas.

They have been saying the models are having a hard time with heaviest QPF amounts and placement.

[srainhoutx]

Monday evening briefing from Jeff:


***Widespread heavy rainfall increasingly likely Tuesday-Thursday over much of Texas with flooding and flash flooding possible***

 

As forecast now for several days, several factors are evolving to produce a round of heavy to excessive rainfall across much of Texas starting Tuesday and ending Thursday. These factors include:

 

1)      A deep upper air trough over northern MX and the SW US

2)      A slow moving frontal boundary

3)      Category 2 hurricane Vance off the SW coast of Mexico

4)      Influx of copious Gulf of Mexico moisture

 

An upper level trough continues to dig into northern MX with a well defined sub-tropical jet cutting from the central Pacific across MX into TX. Small but still powerful hurricane Vance is being picked up by this trough with extensive mid and high level moisture pouring northeast into TX as clearly noted by the increased high level cloud deck this afternoon. Increased southwesterly wind shear over Vance on Tuesday should effectively decapitate the hurricane with the mid and upper level center and moisture moving NNE while the low level center heads more NNW or NW…the downstream result over TX will be the same…rain and a lot of it!

 

Surface frontal boundary now entering NW TX will slowly progress southeastward toward the TX coast by late Wednesday. At the surface SE winds are transporting a rich tropical air mass over the western Caribbean toward the NW Gulf coast and this should arrive on Tuesday. PW values (the integration or summing of the moisture content of the air column from the surface to around 300mb) has nearly doubled at both Corpus Christi and Del Rio in the past 24 hours as moisture from Vance and the Gulf of Mexico are clearly being sampled by the upper air sounding stations at these sites.

 

Tuesday:

The trough over MX will begin to eject disturbances into TX while the frontal boundary slowly moves southeastward. The combined lift from the disturbances and the front will produce showers and thunderstorms from SW to NE TX on Tuesday. For the most part think SE TX will remain fairly dry on Tuesday except for any NNW moving streamer showers in the convergent onshore flow pattern off the Gulf. Heavy rains will focus over SW, WC, and N TX on Tuesday.

 

Tuesday night:

Heavy rainfall and flash flood event increasingly likely over SW and SC TX. Slow moving frontal boundary will become nearly parallel to the SW to NE upper level flow resulting in a slowing of the frontal slope and high threat for repeat cell training. Strong low level inflow off the Gulf and near saturated air column with PWS of 1.85-2.10 inches supports warm rainfall production and potential excessive rainfall cores. A large band of heavy rainfall with embedded excessive rainfall will likely be ongoing by late evening from SW TX across central TX into the NW counties of SE TX.

 

Wednesday:

Heavy to excessive rainfall potential shifts with the frontal boundary toward the coast plains. Expect widespread heavy rainfall to commence early Wednesday morning and last through much of the day from SW TX across the coastal bend into all of SE TX. While the frontal boundary will reach the coast late in the day the threat for overrunning rainfall remains as the upper trough is slower to move out of NE MX and this could keep high rain chances going into Wednesday night especially along and SE of US 59.

 

Thursday-Friday:

Main energy of the upper trough will move across S TX with current models wanting to focus the heavy rainfall over S TX.

 

Rainfall Amounts:

PWS climb to +2 SD above normal for early November which raises a red flag especially when coupled with high potential for cell training. Effectively we will have summertime moisture levels with wintertime dynamics. Such summer rainfalls tend to be isolated in nature with lift focused by daytime heating and for a short period of time…however this time of year strong lift is focused for potentially hours due to jet stream dynamics aloft which can keep the excessive rainfall hose going for a much longer period of time as long as the moisture is being funneled into the storms. We will have no shortage of moisture.

 

Given the excessive moisture values high hourly rainfall rates under the stronger storms appear likely in the 2-3 inch range. This will create concerns in the urban areas and in the hilly terrain along and west of I-35 where the flash flood risk is maximized with such rainfall rates.

 

Widespread rainfall amounts of 2-4 inches are likely with isolated totals of 4-7 inches possible especially in an arcing corridor from SW TX to near San Antonio to near Giddings. This setup certainly has the potential to produce some “incredible” rainfall amounts and almost every time we see one of these events some location will get 10 inches or more.

 

Simply stated….a tremendous amount of water is going to be dropped over the state in the next 72 hours.

 

Aside:

“While the current QPF fields are justified given the model output, such values are almost always too low in such events. Small scale intense rainfall cores due to cell training or cell mergers will almost certainly occur and under these locations significantly higher rainfall amounts will reside. These amounts could be upwards of 10 inches or greater in less than 6 hours. Neither I nor any computer model can resolve the location of such intense rainfalls usually until the situation is underway. Such setups are frustratingly difficult to determine due to the meso and micro scales on which they tend to occur…usually on the order of 10’s of miles or less. Yet they are almost always associated with devastating flood responses and life threatening flash flooding.”

 

Hydrologic Response:

While the past several weeks have been dry across much of the area and state and many areas are still suffering from long term hydrological drought, this event has the potential to produce significant run-off and rises on area watersheds. The initial focus will be on the urban areas where excessive rainfall rates will overwhelm primary drainage systems (curb and gutter systems) resulting in deep ponding on roadways and in the flash flood alley section of TX along the I-35 corridor where low water crossings will likely become inundated. Toward the end of the week the widespread nature of the event will likely induce rises on area rivers as generated flood waves make their way into the mainstem rivers and begin to work downstream. As noted above if I cannot determine where the greatest rain will fall at this point I cannot determine which watershed basins will be most impacted and have the greatest response. For the moment I feel there is an equal threat across all basins.   

[Ntxw]

Latest Euro weeklies are out. Interpretation, mid month cold blast then another one near Thanksgiving. Take it for what it's worth, keeps low heights across Texas the entire month which means warm ups will be hard to come by.

[JDawg512]

It's true that we won't know where the heaviest amounts will fall until it does but weatherdude1108 has a point. The past several big rain events have hit Austin hard with flooding and even loss of life but the lakes got little runoff. It would be ideal to see the heaviest amounts fall west within the Colorado River Basin and where there is the least amount of population while the urban areas get steady but not overwhelming ammounts. Of course having the ideal placement is a wildcard at best. I just hope whatever happens that people take precautions and stay safe.

[somethingfunny]

This is gonna have major impacts on the downstream pattern. Even the Euro has 913mb... and I don't think the models have fully reconciled the effects on the jet stream yet.

[ravyrn]

Slightly off-topic: But I just purchased a good-bit of bluebonnet seeds that I aim to place around my mom's property when I house sit for her this weekend. Any advice on what to do to increase the chance of the seeds taking? I purchased approximately 2000 seeds. She's always wanted them in her yard and surrounding area, so I'm hoping to give her a big surprise this Spring. I hope the OT of this post can be excused since its a TX WX thread Feel free to just shoot me pms with advice if you have any experience with bluebonnet seeds so we don't detract from the weather convo.

[gpsnowman]

Good morning all-nighters and early risers. Radar looking juicy at 4:40 this morning in the western part of Texas. Slowly moving this way. Hoping for a long day of rain, rain, and more rain. Will we have an arctic surprise later? We shall see.
Although I am not a big fan of Accuweather and their website, I enjoy reading Joe Lundbergs columns. He is very thorough and never hypes up weather events. Check out his post from yesterday. In the last paragraph he touches on what he sees for signs of the upcoming winter. Always a good read.