Flash Flood Warning 18, NWS Austin/San Antonio, TX

181 
WGUS74 KEWX 041029
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
529 AM CDT Tue Jun 4 2019

TXC137-271-465-041245-
/O.CON.KEWX.FF.W.0018.000000T0000Z-190604T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kinney TX-Edwards TX-Val Verde TX-
529 AM CDT Tue Jun 4 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 AM CDT FOR
WESTERN KINNEY...WESTERN EDWARDS AND EASTERN VAL VERDE COUNTIES...

At 524 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area, covering eastern Val Verde County, 
Western Edwards County, and Western Kinney County. Up to 3.5 inches 
of rain have already fallen. Flash flooding is likely occurring 
across part of the warning area, with heaviest rainfall indicated to 
have fallen from near Laughlin AFB to 8 miles southwest of Kickapoo 
Cavern State Park. 

Some locations that will experience flooding include... 
Del Rio, Rocksprings, Comstock, Loma Alta, Lake View, most of the 
Amistad Recreation Area, and Kickapoo Cavern State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

&&

LAT...LON 3029 10091 3029 10053 3001 10016 2909 10067
      2918 10078 2920 10077 2926 10081 2928 10087
      2931 10089 2935 10097 2942 10104 2946 10106
      2947 10110 2960 10125 2963 10125

$$

MO

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
118 AM CDT Tue Jun 4 2019

.AVIATION... /06Z TAFS/
Pwat values are pushing above 2.0 up the Rio Grande Valley as a
disorganized tropical distubance over the Wrn Gulf has moisture being
pulled into the conveyor belt ahead of an upper low digging into the
SWrn US. Nocturnal LLJ winds are thus generating numerous showers and
storms around DRT, and this may continue for several hours. As
heavier cells converge on the vcnty, will throw in some updates for
occasional gusty winds to 20 knots and vsbys around 2 miles or less.
CAMs models are performing poorly with this convection as a whole,
but the TX Tech WRF initializes well and will be the followed model
for convective concepts throughout the TAF periods. Low cigs will
continue to follow a mix of persistence and climatological
applications of tropical air, and thus are not to be trusted for much
more than a few hours at a time. In other words, the rain areas are
likely to dictate the low cloud trends. Most of the higher res models
lower the rainfall activity around DRT after daybreak and rekindle
convection in the late afternoon. Along I-35 mimimal activity is
expected this morning, but a surge of 2.0 or higher Pwat values after
18Z should generate prevailing showers and a few thunderstorms by 22Z
or perhaps a couple hours earlier. Based on the TX Tech WRF, the
influx of moisture lures the convective clusters impacting DRT in the
morning eastward with prevailing SHRA/TSRA to impact the I-35
terminals in the 22Z-03Z timeframe. This does not have much support
from other CAMs solutions, so will shy away from prevailing showers
until future solutions converge on a mesoscale trend.

&&

.PREV DISCUSSION... /ISSUED 615 PM CDT Mon Jun 3 2019/

AVIATION...
Ongoing shower/convective activity for our far western counties is
expected to linger for the next few hours. Have VCSH in for DRT for
this reason. Just like the previous two evenings, a round of
convection is expected to fire over the Mexican Mountains and track
east giving DRT a chance at some thunder late this evening and
overnight. This activity is not anticipated to impact I-35 sites. All
sites will drop to MVFR tonight with SAT and SSF having a chance for
brief IFR conditions. Late morning and afternoon mixing will lift
all sites back into VFR tomorrow. Rain chances increase for Tuesday
and thunderstorms are in for AUS and SAT at the end of the period.
Will need to monitor later model runs to see if this timing needs to
be altered.

PREV DISCUSSION... /ISSUED 250 PM CDT Mon Jun 3 2019/

SHORT TERM (Tonight through Tuesday night)... Isolated convection
through the remainder of the afternoon and early evening will be
confined across southeast counties along the sea-breeze as well as
near the Rio Grande, closer to low level theta-e ridge axis. Late
this evening and overnight the focus shifts to upstream convection.
Hi resolution models are again showing a complex of storms developing
through the Big Bend and northern Mexico this evening, and moving
east into the Rio Grande and southern Edwards Plataea overnight.
While deep layer shear is marginal this far east, CAPE and DCAPE
values will support a few strong to near severe storms across
Val Verde county, with straight-line winds the primary threat.
This complex is forecast to weaken Tuesday morning.

Attention then shifts to tropical moisture and the broad area of low
pressure currently over the Bay of Campeche. There continues to be
disagreement in the models with the potential development of this
system. Currently NHC gives the system a medium (60%) chance for
development into a tropical cyclone over the next day or two, before
reaching northeast Mexico. The GFS and ECMWF continue to advertise a
broad low moving northwest tonight and Tuesday, then opening in
advance of the trough approaching from the west. An opening system
like this may allow for a deeper tropical tap of moisture into
eastern areas of the CWA late Tuesday through Wednesday. However,
should the system strengthen into a tropical cyclone then deeper
moisture could be consolidated into and to the east of the center.
This would keep heavier rainfall east of the CWA, near the Middle
and Upper Texas coasts, and a shaper rainfall gradient on the
western side over the EWX CWA. Given the uncertainty this is a lower
confidence rain forecast and could likely change depending on the
exact evolution of the system.

For now the forecast package reflects an open system, with the
leading edge of tropical moisture arriving into southeastern areas of
the CWA Tuesday afternoon and night, where scattered showers and a
few thunderstorms possible. Farther west, another upstream complex of
storms is possible across western areas of the CWA late Tuesday
night.

LONG TERM (Wednesday through Monday)...
As mentioned above, forecast rainfall amounts and PoPs for Wednesday
are highly conditional on the eventual evolution of the tropical
system. For now, the forecast package reflects a blend of the GFS and
ECMWF, with deeper tap of tropical moisture spreading through the
eastern CWA Wednesday in advance of the upper level trough
approaching from the west. Precipitable water values are progged to
be near 2" along the I-35 corridor and near or in excess of 2.25"
closer to the U.S. 77 corridor. Likely PoPs are indicated across the
Hill Country and I-35 corridor for Wednesday, with categorical PoPs
and a mention of locally heavy rainfall east of I-35 and I-37.
Between 1-3" are currently forecast where the categorical PoPs are
shown. Again, these amounts could likely evolve over the next day.

As the upper level trough and closed low advances east into West
Texas Wednesday night and Oklahoma on Thursday the deeper tropical
moisture tap gets shunted east of the CWA. Rain chances look to come
to and end by Friday.

An upper level ridge is then forecast to build over the region Friday
through the weekend. Model guidance has been trending warmer with
temperatures during this time. High temps Saturday and Sunday are
forecast to be into the mid and upper 90s across the Hill Country
and along and east of I-35 and I-37, while 100-104 is forecast
across the southwest CWA. Forecast heat index values of 105-110 are
forecast for many areas, outside of the Hill Country, both days.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              73  85  72  91  73 /  50  70  40  20  20
Austin Bergstrom Intl Airport  73  85  72  91  72 /  50  70  40  20  20
New Braunfels Muni Airport     73  85  72  91  72 /  50  70  40  20  20
Burnet Muni Airport            71  84  71  90  71 /  40  70  40  20  20
Del Rio Intl Airport           72  91  73  95  74 /  60  30  20   0  10
Georgetown Muni Airport        72  84  72  90  72 /  50  70  40  20  20
Hondo Muni Airport             73  88  72  95  72 /  40  50  30  10  20
San Marcos Muni Airport        73  85  72  92  73 /  50  70  40  20  20
La Grange - Fayette Regional   75  86  74  91  75 /  60  80  50  40  20
San Antonio Intl Airport       73  86  73  93  73 /  50  70  30  20  20
Stinson Muni Airport           74  87  74  93  74 /  50  70  30  20  20

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

Aviation...Oaks
Short-Term/Long-Term...Hampshire

Hazardous Weather Outlook...UPDATED
National Weather Service Austin/San Antonio TX
309 PM CDT Mon Jun 3 2019

TXZ171>173-183>194-202>209-217>225-228-042015-
Llano-Burnet-Williamson-Val Verde-Edwards-Real-Kerr-Bandera-
Gillespie-Kendall-Blanco-Hays-Travis-Bastrop-Lee-Kinney-Uvalde-
Medina-Bexar-Comal-Guadalupe-Caldwell-Fayette-Maverick-Zavala-
Frio-Atascosa-Wilson-Karnes-Gonzales-De Witt-Lavaca-Dimmit-
309 PM CDT Mon Jun 3 2019

This Hazardous Weather Outlook is for South-Central Texas..

.DAY ONE...Tonight.

Scattered strong thunderstorms are possible across Val Verde
county tonight. The primary threat will be for locally heavy
downpours, with a few storms capable of producing small hail and
strong wind gusts.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Tropical moisture is forecast to work into portions of South
Central Texas late Tuesday through Wednesday night, bringing an
increased chance for showers and thunderstorms. Some pockets of
locally heavy rainfall will be possible east of I-35 and I-37,
where 1-3 inches of rainfall is forecast.

Hot and humid conditions are expected over the area Friday through
Sunday. Heat indices are forecast to reach 105 to 110 degrees
across many areas Saturday and Sunday, with slightly lower values
expected over the Hill Country.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Special Weather Statement
National Weather Service Austin/San Antonio TX
146 AM CDT Tue Jun 4 2019

TXZ183-040730-
Val Verde TX-
146 AM CDT Tue Jun 4 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN VAL VERDE COUNTY
UNTIL 230 AM CDT...

At 144 AM CDT, Doppler radar was tracking a strong thunderstorm near
Cienegas Terrace, or near Del Rio, moving north at 20 mph.

Winds in excess of 40 mph will be possible with this storm.
Torrential rainfall of 1 to 3 inches per hour is expected from this
storm, which could lead to localized flooding through 230 am CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 2986 10108 2963 10070 2936 10071 2934 10071
      2932 10075 2928 10074 2924 10076 2928 10087
      2931 10089 2933 10094 2935 10095 2936 10100
      2944 10106 2946 10106 2948 10116
TIME...MOT...LOC 0644Z 197DEG 18KT 2928 10096

MO