Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Austin/San Antonio Texas
814 PM CST Sat Nov 22 2014
to extend Severe Thunderstorm Watch.
risk of severe thunderstorms will continue with a line of
thunderstorms moving toward the east. The line currently extends
from San Antonio to Pleasanton to cross. As this line moves to the
east there will be a risk for thunderstorms capable of producing
large hail and damaging winds. There is also a slight risk for
tornadoes. We have extended the Severe Thunderstorm Watch to the
counties east of Bexar and along and south of I-10.
Previous discussion... /issued 715 PM CST Sat Nov 22 2014/
Update... /svr watch 557 extension into Bexar...Atascosa/
a progressive squall line is quickly shifting the severe potential
into the San Antonio metropolitan area. Apex of a curved squall line
increases the potential for severe activity associated with cell
mergers as new convection forms east of the line. Cell mergers
will also be possible over parts of Atascosa County by 8 PM.
Expect to see a heavy rain producing mesoscale convective system take shape once the
merged cells move east of I-35...with decreasing severe potential
by 10 PM.
Previous discussion... /issued 607 PM CST Sat Nov 22 2014/
Update... /issuance of flash Flood Advisory/
with the majority of hi-res models indicating large areas of 1-2
inch rainfall still possible over eastern counties...have issued a
Flash Flood Watch for counties along and east of a Llano to San
Antonio line and along and north of a San Antonio to Hallettsville
line. The flash flood threat will probably be enhanced through 9
PM over the eastern Hill Country into Austin metropolitan with some
training cells increasing from Lake Medina to Burnet. After 9 PM...the
focus for flooding should begin to shift east of I-35. Lcra
hydromet indicates several reports of 2 plus inches of rain has
fallen still within the past 6 hours over areas in the paths of
new convection. Isolated minor river rises are expected...but
moderate flood levels are unlikely. The severe threat continues
for much of this evening...especially over the Rio Grande plains.
However...the severe threat should trend toward more isolated
activity late this evening.
Previous discussion... /issued 551 PM CST Sat Nov 22 2014/
main concern is the ongoing convection across the region. An area
of thunderstorms is moving away from drt and there will be a
chance for thunderstorms and rain for the next couple of hours. These storms could
lower ceilings/visible to MVFR. San Antonio airports will be VFR and rain
free for the next few hours. Then there will be a chance for thunderstorms and rain
to lower ceilings/visible to IFR between about 02z and 05z. At aus ceilings
are IFR and there will be rain showers/thunderstorms and rain around for much of the
evening. By 06z convection should end and conditions will be VFR at
all terminals through the end of the period.
Previous discussion... /issued 349 PM CST Sat Nov 22 2014/
The risk of severe weather and heavy rain continues
through this evening...
Short term (tonight through Sunday night)...
strong storms and heavy rain will continue to affect mainly the
eastern half of south central Texas for the next several hours.
The threat for strong to severe weather still exists through this
evening. A second round of showers and storms currently ongoing
across the serranias del burro (northeast mexico) is forecast to
push eastward and across most of south central Texas this evening.
The hrrr and tech-tech hires models develop an mesoscale convective system around 23z/5 PM
this afternoon while a line of showers and storms form ahead of a
surface convergence zone (warm sector). If this scenario pans
out...strong to severe storms are possible across the Rio
Grande...especially along and west of Rocksprings to Hondo to
Pearsall line. A Severe Thunderstorm Watch is in effect through 10
PM tonight for the area above mentioned. Main weather threats will
be large hail and damaging winds. Can't rule out an isolated
tornado or two. Some of these strong storms will produce heavy
downpours with rainfall accumulations up to one inch per hour.
The mesoscale convective system is forecast to combine with the showers and storms
expected to form along the convergence zone and move east in a
linear fashion...affecting the I-35 corridor around 8 or 9 PM this
evening. By 9 PM...the system is likely to transition to a heavy
rain producer with stronger storms capable of producing large
hail. The line of storms will quickly push to the east by midnight
tonight with rain chances coming to an end across the entire area
by 2 or 3 am Sunday. New rainfall amounts for the tonight period
could range from 1 to 2 inches and up to 3 inches in isolated
On Sunday...expect mostly sunny/clear skies across south central
Texas with breezy conditions. A Pacific cold front will push
across the region Sunday night into Monday.
Long term (monday through saturday)...
the weather is expected to be fairly quiet for much of next week. A
weak front will move through the area overnight Sunday. This front
is in response to an upper level trough moving through the plains.
The weather for Thanksgiving should be pretty seasonal with highs
in the 60s and lows in the 30s/40s.
Preliminary point temps/pops...
Austin Camp Mabry 55 78 45 64 40 / 60 0 - - -
Austin Bergstrom international Airport 54 77 43 64 37 / 70 0 - - -
New Braunfels Muni Airport 55 79 45 66 40 / 60 0 - - -
Burnet Muni Airport 52 75 42 62 38 / 50 0 - - -
del Rio International Airport 50 78 46 65 38 / 30 0 - - -
Georgetown Muni Airport 54 75 43 62 38 / 60 0 - - -
Hondo Muni Airport 49 77 42 65 37 / 50 0 - - -
San Marcos Muni Airport 53 78 44 65 39 / 70 0 - - -
La Grange - Fayette regional 57 78 46 64 40 / 90 0 - - -
San Antonio International Airport 54 78 46 66 41 / 50 0 - - -
Stinson Muni Airport 54 79 46 66 41 / 60 0 - - -
Flash Flood Watch until midnight CST tonight for the following
public service/data collection...30