Special Weather Statement, NWS Austin/San Antonio, TX

Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
823 PM CDT Tue Apr 3 2018

.UPDATE...
Cancelled the western tier of counties of the Severe Thunderstorm
Watch 29. The Severe Thunderstorm Watch continues for areas east of
Interstate 35 and includes Bexar county through midnight night.

The cold front extends from a Giddings to Luling to San Antonio line.
Showers and thunderstorms have been developing along the front across
the eastern portion of the area as the boundary enters into a
favorable area for storms to generate. Some storms are expected to
become strong to marginally severe as the cold front moves towards
the coastal plains. The main weather threat will be large hail and
thunderstorm wind gusts of 60 mph. The front will be pushing away
from the area around midnight tonight and chances of rain come to an
end.

&&

.PREV DISCUSSION... /ISSUED 640 PM CDT Tue Apr 3 2018/

AVIATION.../00Z TAF CYCLE/

A strong cold front is currently moving south across the Hill Country
and northern I-35 corridor nearing KAUS. SHRA and a isolated TSRA
will develop on and behind the front as it moves south. Main
aviation impact will be the VCTS for KAUS/KSAT/KSSF from 00Z-04Z.
Furthermore, gusty north winds will occur immediately behind the
front with sustained 15-20 with gusts of 25-35 mph likely. Have
placed both VCTS for the central TAF sites and increased wind speeds.
If TSRA was to directly shift over terminal then drop in visibility
to 4SM could be possible. However, overall coverage should remain
isolated to scattered and not place this in a TEMPO group at this
time. Winds will decrease through the overnight to 10 to 15 knots by
morning as VFR prevails through the period.

PREV DISCUSSION... /ISSUED 622 PM CDT Tue Apr 3 2018/

UPDATE...
A new Severe Thunderstorm Watch is in effect for areas east of
Highway 281 and Interstate 37 through midnight tonight. The main
weather hazards through the period will be large hail and
thunderstorm wind gusts of 60 mph.

A cold front is pushing across the northern part of the Hill Country
and expected to generate a line of strong to marginally severe
thunderstorms as the frontal passage enters a more favorable
environment area (east of I-35) for storms to develop. The cold front
and expected weather associated with it should come to an end around
midnight tonight when the frontal boundary pushes to the southeast
and away from the area.

PREV DISCUSSION... /ISSUED 342 PM CDT Tue Apr 3 2018/

SHORT TERM (Tonight through Wednesday)...

Primary focus remains on the strong to severe thunderstorm potential
for portions of the Hill Country, into the I-35 corridor, and the
Coastal Plains this afternoon and through the evening. Main hazards
will be large hail (possibly to the size of tennis to baseballs),
40-60 mph winds, and frequent lightning. Main hazard window for
strong/severe storms will be from 3pm this afternoon in the north
Hill Country through the late afternoon and early evening near Austin
and then mid to late evening for the Coastal Plains. Windy
conditions will also occur behind the front with gusts to 25-35 mph
this evening and overnight.

Mesoscale Environment: A strong cold front is analyzed along a San
Angelo to Comanche to Greater Dallas/Fort Worth metroplex. This front
is intersecting a north to south oriented dryline extending south
from Junction to Rocksprings to Del Rio. A warm sector to the south
and east of these boundaries is characterized by 2500-3000 J/kg ML
CAPE with 80-20 J/Kg CIN with 0-6km shear near 40-50 knots while mid
and upper level divergence overspreads the region from a passing
shortwave trough over the Rio Grande. Impressive and very steep
lapse rates of 8-9C/Km are analyzed to be in place over the entire
region. This will support very robust updrafts capable of producing
large hail. Latest satellite imagery indicates more agitated cumulus
across far north Williamson and Burnet ahead of the strong front two
county tiers north. Latest aircraft soundings out of Austin show a
slow erosion of the capping inversion over the past two hours. The
ample cloud cover from this morning has helped stabilize the I-35
corridor but cloud opacity has decreased over the past hour and
surface temperatures have warmed. Both the surface heating and
dynamic lift as noted through cooling mid/upper level clouds should
act to weaken the capping inversion next 1-2 hours.

The cold front will help provide the surface convergence needed to
help get over the cap as well. A broken line of strong/severe
thunderstorms is expected to develop through the afternoon and
evening. This line will shift southeast this afternoon and evening
with hazards ending north to south. All hazards will end near
midnight as the front clears towards the Texas Coast.

Much cooler and drier Wednesday morning as temperatures fall into the
mid 40s. Wind chills may actually feel like the upper 30s in some
select locations. Near-critical fire weather conditions will occur as
humidity falls into the mid teens to low 20s. Temperatures will only
reach to near 70F.

LONG TERM (Thursday through Tuesday)...

A conditional hazard window exist Friday afternoon and evening for
strong to severe storms depending on the next frontal timing and peak
instability collocation evolution. Near to above normal temperatures
are expected late week into Friday before a cool down near normal
over the weekend behind the front. Dry conditions are expected
through the weekend with humid conditions returning late weekend
prior to another frontal passage Monday.

A fluctuation of airmass changes will occur late week and into early
next week as the dry and moist airmasses swing back and forth across
south-central Texas. Humid conditions will return Thursday and
Friday with dewpoints back into the mid to upper 60s. Strong to
severe storms look probable for north and central Texas where some
greater forcing will be in place. The strength of the capping
inversion will be key for storms this far south on Friday afternoon
and evening. If storms do not happen to form over the Hill Country
Friday then activity strength should wane prior to its arrival along
the front early Saturday morning. However, if the front move faster
then currently advertised or impulses pivot southward, this could
help promote storms farther south.

The cold front will shift through Saturday morning with rain and some
thunder associated with it. Overall totals don't look to be too
hefty currently given the progressive nature. A dry Sunday is
expected with a reinforcing cold front being a possibility on Monday
with a dry Tuesday looking probable.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              47  71  51  79  65 /  40   0   0  -   20
Austin Bergstrom Intl Airport  46  70  48  79  66 /  40   0   0  -   20
New Braunfels Muni Airport     48  70  50  79  66 /  40   0   0  -   20
Burnet Muni Airport            42  68  48  77  63 /  10   0   0   0  10
Del Rio Intl Airport           55  75  53  82  64 /  -    0   0   0  -
Georgetown Muni Airport        44  69  48  78  64 /  20   0   0  -   20
Hondo Muni Airport             51  74  51  81  65 /  20   0   0   0  10
San Marcos Muni Airport        47  70  50  79  66 /  40   0   0  -   20
La Grange - Fayette Regional   48  70  51  78  67 /  60   0   0  10  10
San Antonio Intl Airport       51  71  52  79  66 /  40   0   0  -   20
Stinson Muni Airport           54  70  53  79  66 /  40   0   0  -   20

&&

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

Mesoscale/Aviation...Runyen
Synoptic/Grids...17
Public Service/Data Collection...Treadway

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
255 PM CDT Tue Apr 3 2018

TXZ171>173-183>194-202>209-217>225-228-042000-
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-
255 PM CDT Tue Apr 3 2018

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

.DAY ONE...This Afternoon And Tonight.

Severe thunderstorms will be possible along and east of a line
from Llano to Kerrville to Uvalde. A strong cold front will move
through this afternoon and evening that will bring the potential
for severe storms with very large hail, perhaps up to 2 inches in
diameter, and straight line winds up to 70 mph.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Please report severe weather to local law enforcement or the
National Weather Service.

Special Weather Statement
National Weather Service Austin/San Antonio TX
437 PM CDT TUE APR 3 2018

TXZ171-172-032230-
Llano TX-Burnet TX-
437 PM CDT TUE APR 3 2018

...SIGNIFICANT WEATHER ADVISORY FOR LLANO AND BURNET COUNTIES UNTIL
530 PM CDT...

At 436 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 11 miles north of Copperas Cove to 6 miles
south of Valley Spring. Movement was southeast at 15 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Burnet, Kingsland, Llano, Buchanan Dam, Gainesville, Granite Shoals,
Horseshoe Bay, Buchanan Lake Village, Highland Haven, Inks Lake State
Park, Watson, Bluffton, Lake Victor, Baby Head, Stolz, Joppa, Oxford,
Shady Grove, Lone Grove and Valley Spring.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Austin San Antonio.

&&

A Severe Thunderstorm Watch remains in effect until 600 PM CDT for
south central Texas.

LAT...LON 3103 9790 3091 9783 3088 9786 3050 9852
      3050 9878 3079 9894 3092 9871 3092 9842
      3094 9841 3096 9845 3098 9844 3101 9846
      3103 9844
TIME...MOT...LOC 2136Z 326DEG 15KT 3128 9791 3076 9881

TB3

Special Weather Statement
National Weather Service Austin/San Antonio TX
647 PM CDT TUE APR 3 2018

TXZ190>192-040030-
Blanco TX-Hays TX-Travis TX-
647 PM CDT TUE APR 3 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN HAYS...NORTHWESTERN
TRAVIS AND NORTHEASTERN BLANCO COUNTIES UNTIL 730 PM CDT...

At 645 PM CDT, Doppler radar was tracking a strong thunderstorm near
Cypress Mill, or 10 miles southeast of Round Mountain, moving east at
40 mph.

Dime to penny sized hail and winds in excess of 40 mph will be
possible with this storm.

Locations impacted include...
Austin, Leander, Lakeway, Lago Vista, Bee Cave, Hudson Bend, The
Hills, Cypress Mill, Pedernales Falls State Park, Mansfield Dam,
Jonestown, Briarcliff, Point Venture, Volente and Lost Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Austin San Antonio.

&&

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

LAT...LON 3032 9781 3022 9825 3039 9832 3045 9821
      3043 9813 3046 9810 3049 9810 3049 9812
      3051 9811 3061 9794
TIME...MOT...LOC 2345Z 250DEG 36KT 3034 9819

TB3

Special Weather Statement
National Weather Service Austin/San Antonio TX
848 PM CDT TUE APR 3 2018

TXZ209-040215-
Fayette TX-
848 PM CDT TUE APR 3 2018

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL FAYETTE COUNTY UNTIL 915
PM CDT...

At 848 PM CDT, Doppler radar was tracking a strong thunderstorm near
Muldoon, or 8 miles southeast of Smithville, moving east at 35 mph.

Dime size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
La Grange, Muldoon, Rabbs Prairie, Swiss Alp, Plum, Rutersville,
Ammannsville, O'Quinn, West Point, Mullins Prairie, Kirtley and
Holman.

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

LAT...LON 2976 9680 2981 9719 2992 9717 2999 9709
      3005 9676
TIME...MOT...LOC 0148Z 272DEG 32KT 2990 9709

MO