Texas Fall-2015

[Portastorm]

Porta you notice the donut hole forming over Texarkana? Figured you might want to make mention considering a certain poster from that area likes to poke fun at SW ATX.

I'll wait until that verifies.

You know what they say about karma.

Meanwhile it is an important note for us all to remember that fire stricken areas will be more prone to flash flooding this week as well as helping burned trees falling down much easier than normal. Something to be mindful of.

[JDawg512]

I agree with the generalized 1-2 inches which is really a good amount to have coming out of a prolonged dry period. Any more and there would be some flooding issues. I'd rather have the rainfall sink into the ground rather than wash away.

Having said that, I don't think it would be a bad idea to monitor for a possible training effect along the Balcones Escarpment. We only need to look back over the last couple of years in October where we saw large amounts of rainfall fall along the I-35 corridor causing major flooding such as the Halloween Flood of 2013.

I'm expecting 1-2 inches though I wouldn't completely rule out higher amounts just yet.

[aggiecutter]

Porta you notice the donut hole forming over Texarkana? Figured you might want to make mention considering a certain poster from that area likes to poke fun at SW ATX.

I drew those maps just to get him excited. Actually, Texarkana will get a lot more rain than SW Austin this weekend. However, I do have some good news for those in SW Austin as far as snowfall is concerned for this winter. I read somewhere(forgot where it was) that SW Austin would receive 500% of the snowfall they have received on average the past 10 years. The bad news is that 500% * 0 = 0. To verify the data, the following statistical methods were used: exponential smoothing, exponential smoothing adjusted for the trend, least squares regression, and the naive method.

[Ntxw]

Discussed it with Porta in the winter thread. Austin is guaranteed Freezing Drizzle.

Nothing new or drastic to add from today's guidance everyone has pretty much got it out. There are strips and several areas that may see 4-6+ inches of rain but those may only be in parts of counties while nearby it may be just an inch or two close by. Hard to predict those things.

There are subtle hints of cross polar flow setting up later this month or early next month. Taste of winter perhaps? A lot will depend on typhoon Champi

[TeamPlayersBlue]

I hope you guys in N Tx get some rain so you can stop being big ole babies about it!

[TheProfessor]

It's been dry here in Ohio, and even worse further west where some areas have seen 0% of their average the last 18 days.

[Brent]

Well I'm back in Texas! Bring on the rain!

and before you ask... it was bright and sunny in Alabama too so I still haven't seen rain. But it was definitely cold the last couple days for mid October and REALLY cold considering what it was when I left here Thursday.

[TheProfessor]

Saw this super times 100 long range map on another forum, I'm sure you Austonians would love it.


imagen

Unfortunately the maps measures in millimeters and not inches

[Ptarmigan]

Hey TPB I think it was you who brought up the October 1972 similarities. Looking like it now with the last two weeks.

1972-1973 El Nino is the strongest El Nino of the 1970s. 1970s was mostly dominated by La Nina.

[TeamPlayersBlue]

Hey TPB I think it was you who brought up the October 1972 similarities. Looking like it now with the last two weeks.

1972-1973 El Nino is the strongest El Nino of the 1970s. 1970s was mostly dominated by La Nina.

The simularities to 2009-'10 are pretty close to this year as well. Very hot October in '09

[weatherdude1108]

Bob Rose:

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

[weatherdude1108]

[South Texas Storms]

That's a really good graphic from EWX.

They also wrote a great, detailed AFD this morning. I agree with their forecast thoughts completely.

"AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
408 AM CDT TUE OCT 20 2015

.SHORT TERM (TODAY THROUGH WEDNESDAY)...UPPER LEVEL TROUGH ACROSS
THE WESTERN CONUS THIS MORNING WITH BASE ACROSS SOUTHERN AND BAJA
CALIFORNIA. TODAY AND TONIGHT WILL BE A TRANSITION PERIOD AS LOW
LEVEL MOISTURE STEADILY ADVECTS INTO THE AREA. THE LEADING EDGE
OF HIGHER MOISTURE ARRIVES INTO FAR EASTERN COUNTIES AS EARLY AS
THIS AFTERNOON...WITH A FEW MODELS INDICATING SOME QPF EAST OF
U.S. 77. STRATUS QUICKLY DEVELOPS LATE THIS EVENING WITH MUCH
WARMER LOWS WEDNESDAY MORNING. A FEW WEAK SHOWERS AND SPRINKLES
POSSIBLE OVERNIGHT.

ISENTROPIC ASCENT BEGINS TO OVERSPREAD THE CWA ON WEDNESDAY AHEAD
OF UPPER LEVEL LOW ACROSS ARIZONA AND NORTHWEST MEXICO. TAP OF
LOW LEVEL MOISTURE FROM THE GULF CONTINUES TO BUILD ACROSS THE
AREA. PWAT VALUES ARE FORECAST TO INCREASE TO AROUND 1.5-1.8
INCHES BY WEDNESDAY AFTERNOON...AND EXPECT TO SEE ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING THROUGH THE DAY.
DEEP LAYER SHEAR OF AROUND 40-45 KTS ALONG THE RIO GRANDE AS WELL
AS MUCAPE VALUES AROUND 1000 J/KG ARE CONDUCIVE FOR A FEW STRONGER
TO POSSIBLY SEVERE STORMS WEST OF A ROCKSPRINGS TO EAGLE PASS
LINE. SPC CURRENTLY HAS THIS AREA IN A MARGINAL DAY 2 RISK.

&&

.LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...

...LOCALLY HEAVY RAINFALL EXPECTED THURSDAY NIGHT THROUGH SATURDAY
NIGHT POSSIBLY LEADING TO FLOODING...

MOISTURE WILL CONTINUE TO INCREASE OVER THE AREA WEDNESDAY NIGHT
THROUGH SATURDAY...BOTH IN THE LOW LEVELS AS WELL AS MID AND UPPER
LEVELS WITH SUBTROPICAL TAP FROM THE PACIFIC. PWAT VALUES BY
THURSDAY AFTERNOON INCREASE TO AROUND 1.6-1.8 INCHES ACROSS THE
WEST AND 1.8-2 INCHES ACROSS THE EAST...ABOVE 2 STANDARD DEVIATIONS
OF NORMAL FOR THIS TIME OF YEAR. THE UPPER LEVEL LOW OPENS THURSDAY
WITH SHORTWAVE EJECTING EAST INTO FAR WEST TEXAS AND THE PANHANDLE.
AHEAD OF THIS...HIGHER PLUME OF MOISTURE AND MID LEVEL FORCING
WORKS NORTHWARD THROUGH THE EASTERN HALF OF THE CWA...LEADING TO
LIKELY POPS ACROSS THE AREA. THERE WILL CONTINUE TO BE A RISK FOR
A FEW STRONGER STORMS ACROSS WESTERN AREAS...SIMILAR TO WEDNESDAY...
CLOSER TO BETTER INSTABILITY AND DEEP LAYER SHEAR.

THURSDAY NIGHT INTO FRIDAY THE LOW LEVEL JET STRENGTHENS TO
NEARLY 40 KTS...AND SYNOPTIC ASCENT INCREASES AHEAD WITH
AFOREMENTIONED SHORTWAVE LIFTING NORTHEAST INTO THE PLAINS. GIVEN
THE FORCING AND ABNORMALLY HIGH PWAT AIRMASS IN PLACE...WE HAVE
BOTH INCREASED POPS AND ADDED MENTION OF LOCALLY HEAVY RAINFALL
INTO THE FORECAST FOR THURSDAY NIGHT AND FRIDAY.

APPEARS THE BEST CHANCES FOR LOCALLY HEAVY RAINFALL WILL OCCUR
SOMETIME SATURDAY INTO SATURDAY NIGHT...WITH A POTENTIAL FOR
HIGHER QPF BULLSEYE LEADING TO FLOODING CONCERNS ACROSS SOUTHERN
AND/OR EASTERN HALF OF THE AREA.

SECONDARY SHORTWAVE DEEPENS THE TROUGH BACK OVER THE DESERT
SOUTHWEST FRIDAY AND FRIDAY NIGHT...AND MOVES ACROSS TEXAS
SATURDAY AND SUNDAY. IT ALSO APPEARS BY BOTH THE 00Z GFS AND ECMWF
THAT THE REMNANTS AND MOISTURE OF PACIFIC TROPICAL SYSTEM PHASES
INTO THE BASE OF THE TROUGH ACROSS NORTHEAST MEXICO AND SOUTH
TEXAS. PWATS VALUES BY SATURDAY ARE FORECAST TO PEAK AROUND
2.1-2.3 INCHES NEAR AND EAST OF I-35 ACROSS THE CWA...AND 1.5-2
INCHES ACROSS WESTERN AREAS. THIS IS APPROACHING MAX VALUES
RECORDED BY CRP/DRT UPPER SOUNDINGS FOR THIS TIME OF YEAR.

FORCING APPEARS TO BE STRONG WITH UPPER TROUGH MOVING ACROSS THE
AREA SATURDAY THROUGH SUNDAY MORNING. IN ADDITIONS...BOTH THE GFS
AND ECMWF INDICATE FORCING DEVELOPING NEAR SFC-H85 LOW AND
FRONT...BUT DIFFER ON EXACT PLACEMENT OF THIS FEATURE ACROSS
SOUTHERN AND EASTERN AREAS OF THE CWA. THIS COULD PLAY A ROLE
WHERE A HIGHER QPF BULLSEYE MAY OCCUR SATURDAY INTO SATURDAY
NIGHT.

AS THE TROUGH MOVES EAST OF THE AREA SUNDAY AFTERNOON AND FRONT
SOUTH...RAIN CHANCES SHOULD GRADUALLY DIMINISH NORTHWEST TO
SOUTHEAST. HOWEVER...THE ECMWF IS NOW INDICATING QPF CONTINUING
ACROSS NORTHERN AND EASTERN AREAS SUNDAY NIGHT INTO
MONDAY...ALTHOUGH NOT HEAVY.

STORM TOTAL RAINFALL ACCUMULATIONS FROM BOTH THE 00Z GFS AND
ECMWF ARE RATHER IMPRESSIVE ACROSS THE EASTERN HALF OF THE
CWA...INCLUDING PORTIONS OF THE HILL COUNTRY AND ALONG AND EAST OF
THE I-35 CORRIDOR. BOTH ARE SHOWING STORM TOTAL ACCUMULATIONS OF
3-6 INCHES FROM WEDNESDAY THROUGH SUNDAY...WITH HIGHER LOCALLY
HIGHER BULLSEYES. HOWEVER IT IS STILL TOO SOON TO PINPOINT EXACTLY
WHERE HIGHER AMOUNTS WILL FALL.

AS WE HAVE SEEN WITH PAST OCTOBER STORMS...THE COMBINATION OF
THESE STRONGER SYSTEMS TAPPING INTO BOTH GULF AND PACIFIC PLUMES
OF MOISTURE CAN LEAD TO HEAVY RAINFALL EVENTS. ALL INTERESTS IN
SOUTH-CENTRAL TEXAS ARE URGED TO CLOSELY MONITOR FORECASTS THROUGH
THE REMAINDER OF THE WEEK AS DETAILS BECOME MORE CLEAR."

[Ntxw]

The models have converged. There is a pretty good consensus and we are now within short to medium range. Most of the rain falls from Thursday through Saturday. Here are various model QPF output for different areas.

Euro

DFW- 7.7"
Austin-5.6"
Houston-5"
Texarkana- 5"

Most everybody receives about 2-4"

GFS (as of 6z)

DFW- 7.14"
Austin- 5.47"
Houston-2.18"
Texarkana-2.75"




Some may get a lot more, some may get less. it will be a slow soaking rain mostly though I would not be surprised if flash flood watches were posted as any kind of rainfall above 5" usually warrants. Heaviest amount likely occurs at the cross between 5h vorticity crossing the state with strong lift meets high surface moisture. Right now it is expected to be near the middle Texas coast and up the I-35 corridor.

Longer range it looks like typhoon champi is going to dislodge an arctic air mass towards the contiguous 48 around Halloween Semblance of cross polar flow

[TheProfessor]

I'm hoping for some good timing so I can see some wintry fun around Halloween.

[Tireman4]

:uarrow: I'm hoping for some good timing so I can see some wintry fun around Halloween.

Yeah yeah yeah..rub it in...ughh..

[dhweather]

Well, we've finally reached a dew point of 60 here in Heath, so return moisture is ramping up. A couple days of this will really help set the table for significant rains to fall this weekend.

[gboudx]

From jeff:

Area will go from drought and fires to heavy rainfall and flooding over the next 5 days.

Large scale pattern change is underway this morning with a deep layer trough starting to move into the SW US. This trough will slow down and begin to pull the mass of deep tropical moisture to our south northward later today and Wednesday. Tropical cyclone formation is likely on the west side of the Mexican coast which will then track NW into the MX coast later this week spreading additional mid and high level moisture northward toward TX. Deep layer low to our west by late week will help to foster a strong coastal trough over the western Gulf of Mexico from offshore of S TX to inland of Matagorda Bay. Moisture levels surge to very impressive levels for late October with PWS of 2.4-2.6 inches likely over much of the region by late Friday into Saturday.

Moisture is already increasing this morning with showers offshore of Galveston and expect the onshore flow to continue to pump moisture into the region today and Wednesday. Rainfall will be scattered at best the next 24-36 hours with significant increase expected on Thursday as strong upper level dynamics ejects into the region from the west and the coastal trough forms along the coast.

Prolonged heavy rainfall event should unfold Friday into late Saturday as strong southerly flow and south to north orientation of the coastal trough leads to sustained cell training of bands over the region. Rainfall rates will greatly increase as moisture levels increase and 2-3 inches per hour will certainly be possible. Models have been really pegging the Matagorda Bay area northward toward College Station the last few runs for a fairly significant band of heavy rainfall. Too early to define specific area that may see the most…but the model agreement is pretty good.

Will go with widespread 2-4 inches across the entire region with isolated totals of 6 inches or greater. Would not be surprised to see a couple of locations with 10 inches or greater.

Tides:
Other aspect will be higher than normal tides. Tides are already running 1-2 ft above normal and this will continue through the end of the week as ENE to ESE winds continue across the entire northern Gulf. Combined effects of wave run-up on the beaches and water transport to the right of the mean wind flow (Ekman transport) support above average tides. Areas just SW of Matagorda Bay have been having some issues at high tide the last few cycles and a coastal flood advisory may be needed from Calhoun County south to near Corpus Christi.

Fire Weather:
Should see vast improvement in the battle against wildfires across the state over the next 24 hours as significant RH recovery is expected today. While fuels will remain very dry…higher RH should help prevent as many fire starts as seen the last few days. Significant rain chances develop over the region Thursday with widespread wetting rainfall expected and this will end the wildfire threat.

[TheProfessor]

:uarrow: I'm hoping for some good timing so I can see some wintry fun around Halloween.

Yeah yeah yeah..rub it in...ughh..

It's rather dry here so in reality I would rather trade some wintry weather for some multi inch rain.

[Tireman4]

:uarrow: I'm hoping for some good timing so I can see some wintry fun around Halloween.

Yeah yeah yeah..rub it in...ughh..

It's rather dry here so in reality I would rather trade some wintry weather for some multi inch rain.

Humm, I see....well I think we will all get in on the moisture at one time or another..