Alert archive / Texas / Special Weather Statements in 2018

Special Weather Statement, NWS Austin/San Antonio, TX

May 4, 2018Blanco County, Texas

NWS Austin/San Antonio, TX issued this special weather statement at May 4, 2018, 8:00 AM CDT for Blanco County, Texas. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 4, 2018, 8:00 AM CDT (13:00 UTC)
Expired: May 4, 2018, 8:45 AM CDT
In force: 45 min
Issued by: NWS Austin/San Antonio, TX

County Blanco County, TX

The radar

The Austin/San Antonio radar (KEWX), 87 km from the middle of the area, began a volume at 13:02 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Del Rio, TX (KDLF), launched 12:00Z, 1.0 hours before the alert went out and 265 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1841 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 466 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 53 m²/s²
0-3 km storm-relative helicity: 131 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 4.1

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Austin/San Antonio, TX wrote its last area forecast discussion before this special weather statement went out at May 4, 6:39 AM CDT, 1 hour 21 minutes earlier.

Area forecast discussion, May 4, 6:39 AM CDT, 1 hour 21 minutes before

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
639 AM CDT Fri May 4 2018

.AVIATION DISCUSSION...
A line of TSRA is moving eastward across the Edwards Plateau and will
be heading towards the I-35 corridor by about 16-18Z. KDRT should see
TSRA ending by mid morning as the cold front moves through there
first and later for I-35 sites. IFR/MVFR changes will be likely
before and during the TSRA passage. TSRA should end for I-35 sites by
mid to late afternoon, after which MVFR is expected to prevail
through the overnight period. Did include TEMPO group for expected
arrival of storms at KSAT/KSSF.

&&

.PREV DISCUSSION... /ISSUED 309 AM CDT Fri May 4 2018/

SHORT TERM (Today through Saturday)...
A complex and challenging short term forecast this morning as the
focus was on the obvious heavy rain potential and what impacts this
may result in over the next 36 hours.

An initial round of convection overnight was sparked by a passing
shortwave which allowed a weak cap to erode and tap into plentiful
instability. This complex even produced an MCV which aided in some
isolated spots receiving around 3-4 inches of rain per radar
estimates near Brackettville. Now that this complex has moved into
the Hill Country and appears to be progressing swiftly northeast, the
focus now shifts to the actual boundary positioned northwest of the
CWA still.

While hi-res models are having quite a bit of difficulty resolving
where convection is taking place both spatially and temporally, the
GFS/ECMWF more or less agree that an area of strong upper level
divergence will develop between now and 15Z, and by the look of radar
trends as of 745Z, it would appear the effects of that divergence are
beginning to take shape. This UL energy is coincident with a
southwest to northeast oriented boundary located just to the
northwest of Val Verde county.

The standout variables at play for today are the very high PWAT
values (exceeding 2" just south of the boundary), aforementioned UL
divergence, and nearly perpendicular 850mb moisture flux into the
boundary (although only about 20-25 kts). While the flow is quite
modest, there should be enough influence from the other variables
mentioned to produce widespread 1-3 inches of rain as this boundary
begins to shift southward and into the CWA. While noted that the hi-
res model suite is performing poorly, the HREF ensemble PMM, HRRR,
and even 00Z NAM12 all bullseye the Hill Country for the highest QPF
values, specifically the Uvalde to western Bexar, to Kerrville, to
Real county and everywhere in between. The uncertainty in amounts is
still quite high, and the stock in some of these outcomes producing
7+ inches doesn't appear likely given the weak moisture flux into the
front noted previously, however, with MUCAPE still over 1000 j/kg,
cannot rule out some isolated amounts of 5-6 inches if any of this
activity gets a convective boost. This will probably result in the
need for a flash flood warning or two at some point but believe the
potential for this should be isolated to the Hill Country and perhaps
the western parts of San Antonio.

A lot of time was spent considering the possibility of a Flash Flood
Watch, but given the uncertainty, the relatively high flash flood
guidance values due to an extended dry period, and the positioning of
the progged highest values avoiding the lower FFG areas in metro
Austin or San Antonio, opted to forego this decision at this time.
However, a short fuse watch may be needed if hi-res guidance
continues to trend upward, the boundary slows, or training of cells
begins to occur.

The bulk of the rain shield should be east of the I-35 corridor by
around midnight tonight and at that point, impact potential should be
decreased substantially as FFG values east of the corridor are quite
high. By Saturday mid-morning, would not be surprised to see the
majority of the CWA rain free as the upper trough continues to speed
up its progged exit.

LONG TERM (Saturday Night through Thursday)...
The long term is rather benign compared to the short term period. As
noted in yesterday's AFD, no notable air mass change is expected
through the next 7 days after today's cold front passage. As a
result, highs each afternoon will likely rise into the mid to upper
80s and eclipsing 90 degrees along the Rio Grande Plains. Continued
to populate the warmer guidance compared to the Superblend values
which decreased temps later in the week. Without significant changes
in moisture, cloud cover, no boundary, nor significant changes in the
synoptic pattern, don't see any reason to bring temps down towards
the late week as it suggested. Only potential concern may be fire
weather related towards late week as afternoon RH values fall into
the 20 percent range in the western zones. But intend on keeping the
HWO clear for the extended period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              75  60  82  60  87 / 100  50  10   0   0
Austin Bergstrom Intl Airport  75  60  81  57  86 / 100  60  10   0   0
New Braunfels Muni Airport     76  61  81  58  86 / 100  60  10   0   0
Burnet Muni Airport            71  56  80  56  86 / 100  40  10   0   0
Del Rio Intl Airport           81  62  87  62  91 /  80  30  10   0   0
Georgetown Muni Airport        73  58  81  56  85 / 100  50  10   0   0
Hondo Muni Airport             77  61  83  57  87 / 100  60  10   0   0
San Marcos Muni Airport        75  60  82  57  86 / 100  60  10   0   0
La Grange - Fayette Regional   79  63  81  58  86 /  80  60  20   0   0
San Antonio Intl Airport       76  62  82  60  87 / 100  60  10   0   0
Stinson Muni Airport           78  63  82  60  86 / 100  60  10   0   0

&&

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

Mesoscale/Aviation...Runyen
Synoptic/Grids...TB3

Hazardous weather outlook, May 4, 4:05 AM CDT, 3 hours 55 minutes before

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
405 AM CDT Fri May 4 2018

TXZ171>173-183>194-202>209-217>225-228-050915-
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-
405 AM CDT Fri May 4 2018

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

.DAY ONE...Today And Tonight.

A line of strong storms is expected to move through South Central
Texas throughout the day today. The primary concern with this line
of storms will be heavy rainfall and localized flash flooding,
however hail and gusty straight line winds will be possible as
well. Generally, one to three inches of rainfall are expected, but
isolated amounts of 5 to 6 inches may be possible.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotters are urged to report severe weather and flooding today
through Friday night.

In the hours before

Special weather statement, May 4, 2:19 AM CDT, 5 hours 41 minutes before

Special Weather Statement
National Weather Service Austin/San Antonio TX
219 AM CDT FRI MAY 4 2018

TXZ183-040815-
Val Verde TX-
219 AM CDT FRI MAY 4 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN VAL VERDE COUNTY
UNTIL 315 AM CDT...

At 219 AM CDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Pumpville, or 19 miles east of Dryden, moving
northeast at 35 mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

Locations impacted include...
Pandale and Hackberry Crossing.

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.

&&

A Severe Thunderstorm Watch remains in effect until 500 AM CDT for
south central Texas.

LAT...LON 3029 10176 3029 10098 3021 10099 2998 10176
TIME...MOT...LOC 0719Z 246DEG 29KT 3008 10179

MO

Special weather statement, May 4, 5:39 AM CDT, 2 hours 21 minutes before

Special Weather Statement
National Weather Service Austin/San Antonio TX
539 AM CDT FRI MAY 4 2018

TXZ183-184-041130-
Val Verde TX-Edwards TX-
539 AM CDT FRI MAY 4 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN EDWARDS AND EAST
CENTRAL VAL VERDE COUNTIES UNTIL 630 AM CDT...

At 538 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 12 miles north of Carta Valley to near Loma
Alta to 16 miles north of Amistad Recreation Area - Long Point.
Movement was east at 35 mph.

Dime size hail and wind gusts up to 50 mph will be possible with
these storms.

Locations impacted include...
Rocksprings, Loma Alta, Carta Valley, Vinegarone, Devils River SNA -
Big Satan and Kickapoo Cavern State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

A Severe Thunderstorm Watch remains in effect until 700 AM CDT for
south central Texas.

LAT...LON 3013 10019 2991 10016 2963 10044 2970 10097
      2989 10086 3003 10087
TIME...MOT...LOC 1038Z 268DEG 31KT 2998 10072 2991 10071 2974 10089

RUNYEN

Special weather statement, May 4, 7:10 AM CDT, 50 minutes before

Special Weather Statement
National Weather Service Austin/San Antonio TX
710 AM CDT FRI MAY 4 2018

TXZ171-188-041300-
Gillespie TX-Llano TX-
710 AM CDT FRI MAY 4 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LLANO AND GILLESPIE
COUNTIES UNTIL 800 AM CDT...

At 710 AM CDT, Doppler radar was tracking a strong thunderstorm near
Tivydale, or 16 miles west of Fredericksburg, moving east at 30 mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

Locations impacted include...
Fredericksburg, Stonewall, Cherry Spring, Enchanted Rock State
Natural Area, Eckert, Tivydale, Crabapple, Doss, Willow City and
Harper.

LAT...LON 3056 9871 3027 9861 3017 9918 3048 9927
      3050 9913 3050 9897 3052 9896
TIME...MOT...LOC 1210Z 255DEG 25KT 3033 9913

RUNYEN

Local storm report, May 4, 7:22 AM CDT, 38 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
722 AM CDT FRI MAY 4 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0720 AM     TSTM WND DMG     1 NNE LEAKEY            29.74N 99.75W
05/04/2018                   REAL               TX   LAW ENFORCEMENT

            LARGE TREE DOWN ON HIGHWAY 83 ROUGHLY 1 MILE
            NORTH OF LEAKEY. HAIL ALSO REPORTED, UNKNOWN
            SIZE.

&&

JR

Local storm report, May 4, 7:40 AM CDT, 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
740 AM CDT FRI MAY 4 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0710 AM     HAIL             4 N LEAKEY              29.79N 99.77W
05/04/2018  M1.25 INCH       REAL               TX   PUBLIC

&&

JR

Special weather statement, May 4, 8:00 AM CDT, 0 minutes before

Special Weather Statement
National Weather Service Austin/San Antonio TX
800 AM CDT FRI MAY 4 2018

TXZ171-172-188-190-041345-
Blanco TX-Gillespie TX-Llano TX-Burnet TX-
800 AM CDT FRI MAY 4 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN BLANCO...SOUTHEASTERN
LLANO...NORTHEASTERN GILLESPIE AND SOUTHWESTERN BURNET COUNTIES UNTIL
845 AM CDT...

At 758 AM CDT, Doppler radar was tracking a strong thunderstorm over
Willow City, or 13 miles northeast of Fredericksburg, moving east at
35 mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

Locations impacted include...
Marble Falls, Round Mountain, Granite Shoals, Horseshoe Bay,
Meadowlakes, Stonewall, Highland Haven, Spicewood, Blowout, Sandy,
Willow City, Longhorn Cavern State Park, Cypress Mill, Eckert,
Pedernales Falls State Park, Cottonwood Shores, Sunrise Beach
Village, LBJ National Historical Park and Highway 281.

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 3043 9812 3035 9818 3022 9872 3043 9880
      3072 9830
TIME...MOT...LOC 1258Z 251DEG 36KT 3037 9868

PLATT

The office that day

Everything else NWS Austin/San Antonio, TX issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 3, 7:32 PM CDT	Special Weather Statement	EWX	Dimmit	58 min
May 3, 8:28 PM CDT	Special Weather Statement	EWX	Kinney	62 min
May 3, 8:30 PM CDT	Special Weather Statement	EWX	Dimmit	60 min
May 3, 8:43 PM CDT	Severe Thunderstorm Warning	EWX	Kinney, Val Verde	41 min
May 3, 9:11 PM CDT	Special Weather Statement	EWX	Zavala	64 min
May 3, 9:42 PM CDT	Special Weather Statement	EWX	Dimmit	63 min
May 3, 10:14 PM CDT	Severe Thunderstorm Warning	EWX	Dimmit	61 min
May 3, 10:40 PM CDT	Special Weather Statement	EWX	Kinney	50 min
May 3, 10:52 PM CDT	Severe Thunderstorm Warning	EWX	Kinney, Maverick	34 min
May 3, 10:56 PM CDT	Special Weather Statement	EWX	Maverick	49 min
May 3, 11:18 PM CDT	Severe Thunderstorm Warning	EWX	Kinney, Uvalde	57 min
May 3, 11:19 PM CDT	Special Weather Statement	EWX	Real	56 min
May 3, 11:51 PM CDT	Areal Flood Advisory	EWX	Kinney, Uvalde	3 hr
May 4, 12:16 AM CDT	Special Weather Statement	EWX	Uvalde	44 min
May 4, 12:39 AM CDT	Special Weather Statement	EWX	Real	66 min
May 4, 12:48 AM CDT	Areal Flood Advisory	EWX	Bandera, Real, Uvalde	3 hr
May 4, 1:58 AM CDT	Areal Flood Advisory	EWX	Bandera, Kerr	3 hr
May 4, 2:19 AM CDT	Special Weather Statement	EWX	Val Verde	56 min
May 4, 2:37 AM CDT	Severe Thunderstorm Warning	EWX	Val Verde	53 min
May 4, 3:10 AM CDT	Areal Flood Advisory	EWX	Val Verde	3 hr
May 4, 3:23 AM CDT	Severe Thunderstorm Warning	EWX	Edwards, Val Verde	67 min
May 4, 4:29 AM CDT	Severe Thunderstorm Warning	EWX	Edwards	61 min
May 4, 5:17 AM CDT	Areal Flood Advisory	EWX	Edwards, Val Verde	3 hr
May 4, 5:25 AM CDT	Severe Thunderstorm Warning	EWX	Edwards, Kerr	50 min
May 4, 5:39 AM CDT	Special Weather Statement	EWX	Edwards	51 min
May 4, 6:00 AM CDT	Severe Thunderstorm Warning	EWX	Edwards, Real	45 min
May 4, 6:09 AM CDT	Areal Flood Advisory	EWX	Edwards	2 hr
May 4, 6:40 AM CDT	Severe Thunderstorm Warning	EWX	Bandera, Edwards, Kerr, Real, Uvalde	65 min
May 4, 7:07 AM CDT	Areal Flood Advisory	EWX	Real	3 hr
May 4, 7:10 AM CDT	Special Weather Statement	EWX	Gillespie	50 min
May 4, 7:46 AM CDT	Severe Thunderstorm Warning	EWX	Bandera, Bexar, Kendall, Kerr, Medina, Uvalde	59 min
May 4, 8:21 AM CDT	Areal Flood Advisory	EWX	Bandera, Gillespie, Kerr, Llano, Real, Uvalde	3 hr
May 4, 8:44 AM CDT	Special Weather Statement	EWX	Bexar	46 min
May 4, 8:45 AM CDT	Severe Thunderstorm Warning	EWX	Blanco, Hays, Travis	60 min
May 4, 8:57 AM CDT	Areal Flood Advisory	EWX	Blanco, Burnet, Kendall	3 hr
May 4, 8:57 AM CDT	Areal Flood Advisory	EWX	Medina	3 hr
May 4, 9:19 AM CDT	Special Weather Statement	EWX	Comal	41 min
May 4, 9:29 AM CDT	Severe Thunderstorm Warning	EWX	Bexar, Comal, Guadalupe	35 min
May 4, 9:31 AM CDT	Areal Flood Advisory	EWX	Bexar, Comal, Hays, Travis	3 hr
May 4, 9:47 AM CDT	Special Weather Statement	EWX	Travis	43 min
May 4, 10:29 AM CDT	Flash Flood Warning	EWX	Hays, Travis	3 hr
May 4, 11:44 AM CDT	Areal Flood Advisory	EWX	Bastrop, Lee, Williamson	3 hr
May 4, 11:50 AM CDT	Special Weather Statement	EWX	Williamson	25 min
May 4, 11:55 AM CDT	Areal Flood Advisory	EWX	Williamson	3 hr
May 4, 12:07 PM CDT	Areal Flood Advisory	EWX	Medina	3 hr
May 4, 1:32 PM CDT	Areal Flood Advisory	EWX	Hays, Travis	3 hr

Nearby

Special Weather Statements in Texas, 2018 Every special weather statement in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.