831
FXUS64 KEWX 120806
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
306 AM CDT Wed Mar 12 2025

...New SHORT TERM, LONG TERM, FIRE WEATHER...

.SHORT TERM...
(Today through Thursday)
Issued at 304 AM CDT Wed Mar 12 2025

Short Term:

Key Messages:

- Critical to extreme fire weather conditions this afternoon
- Strong west to northwest winds and patchy blowing dust expected
this afternoon across the southern Edwards Plateau, Rio Grande and
Hill Country

Morning stratus is beginning to take shape over the Coastal
Prairies, but looks slow to materialize given the shallowness of the
Gulf moisture layer. This means the morning cloudiness may be short
lived with most skies becoming partly cloudy by 11 AM. Out west of
Hwy 83, the clouds will likely never reach that far inland, and a
dry-line will be entering the picture and mixing down to the surface
from 7 AM to 9 AM.

By 10 AM, a mid to upper trough moving aggressively NE over NW TX
will assert it`s influence on the low levels and push surface winds
to the W/SW quickly into the eastern Hill Country. by 18Z the strong
mid level wind sector begins pushing surface gusts to greater than
40 mph, leading to an extreme fire weather condition over the higher
terrain as is discussed in the fire weather section. South of the
escarpment and Hwy 90, the winds aloft may not have as much
translation to the surface, since this mid-level pattern of tightly
packed mid-level isobars shift rather quickly NE into North Central
TX. Hot air from downsloping will make the arrival of the Pacific
front hard to depict but a brief sighting of it`s merger over the
eastern Hill Country may be seen in the wind direction discontinuity
by mid-afternoon. Our highs over the westernmost counties will end
up ranging from 90 to 100 from the downsloping. A wind advisory and
mention of blowing dust looks on track with what earlier forecasts
have assessed.

The shift into the I-35 corridor in the late afternoon and early
evening hours will begin to take the look of a Pacific front only,
and a slightly lower and more uniform W/NW wind. This will leave the
impact on fire weather conditions with lower confidence, since the
shorter period of elevated winds may not be able to bring the driest
air into that region in time. By mid evening, winds should be
relaxing area wide with a few gusts over 30 mph possible through 9
PM. Not enough decoupling is expected in the lowest levels
overnight, so there could be a complicated pattern of low temps
based on the eastern Hill Country and Austin area holding onto
slightly more winds later at night, and other areas decoupling more
to let the very dry dew points have more impact on the minimum
temperature.

Finally, there is also very low chance (10%) of an isolated shower
or storm developing just ahead of the front late in the afternoon
and early evening, mainly around Lee County.  If a rogue storm
develops conditions would be favorable for the storm to become
strong to severe. SPC has clipped portions of Lee County in a Level
1 out of 5 risk for severe storms, with hail and damaging wind gusts
the threats. Again, this is a very low probability, and the majority
of model runs have the convection forming much farther east.

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 304 AM CDT Wed Mar 12 2025

Key Messages:

- Breezy to strong winds with critical fire weather Friday and
Saturday

- Slightly cooler this weekend before temperatures warm back up

- Lack of rain continues; additional fire weather concerns are
possible into/through next week

The next upper level storm system approaches the central plains
entering Friday. A powerful and strengthening surface low is
forecast to develop as a result of this upper level trough over
Kansas into Nebraska. This low pressure system will increase the
regional pressure gradient and a rather strong nocturnal low-level
jet will intensify late Thursday night into early Friday over the
region. This will allow for low-level moisture advection in the
region, especially east of the I-35 corridor. A low stratus deck
could establish across those locations into Friday morning. A
dryline then moves in from the west, which will be followed and
overtaken by another Pacific front. Breezy westerly winds will
establish in the wake of these boundaries and this will help to
bring in much drier air. The strongest winds will focus over the
northern half of the area. A Wind Advisory could be considered
across the Hill Country. These conditions will result in another
critical fire weather event across much of the region. Specifics on
this will be found below in the fire weather discussion. Moderate
winds could continue Friday night but speeds look to subside
slightly from the peak values on Friday afternoon.

A secondary upper level disturbance closely follows the original
upper level system with the 500 mb base digging further south and
more centrally aligned across South-Central Texas. Despite the
cooler daytime highs on Saturday than Friday, the diurnal mixing
will be enough to support another strong wind and critical fire
weather episode across the region on Saturday. This potentially
could have a larger footprint across our region than the event on
Friday. More on the critical fire weather threat on Saturday can
again be found below within the fire weather discussion. A Wind
Advisory could be necessary once again on Saturday as well.

The winds will gradually settle down from Saturday night into the
start of next week as surface high pressure establishes over the
region and as the upper level pattern tames into more of a weak
ridging and zonal setup. The slightly cooler airmass will also
maintain with afternoon highs in the 70s to low 80s and the
overnight lows dipping into the 40s. The surface high will then
slides east from Monday into Tuesday. This will turn and increase
winds from the south. This also allows for temperatures to start
warming up entering the middle of next week. Another storm system
will then pass north of the region around Wednesday. This allows
another front to arrive to the area and could increase the fire
weather concern once more in it`s wake.

Long term continues to remain bleak for the prospect of any rain
across the region. There is some hints of a little mid-level
moisture that could pass on Saturday morning across the coastal
plains. However, the low-levels are to remain very dry and would
keep anything falling out of the clouds as virga. This lack of
rainfall will continue to compound our long term drought and
concerns for fire weather as fuels continue to severely dry out.

&&

.AVIATION...
(06Z TAFS)
Issued at 1245 AM CDT Wed Mar 12 2025

Dew point temps in the middle 50s and the 20-35 knot winds off the
deck should help churn up some low MVFR clouds for the I-35
terminals by around 09Z. In this dry air regime the mostly decoupled
winds closer to daybreak could fall to near IFR, but with such
shallow levels of moisture moving in, will only show a short tempo
group for SAT. Lower dew points in the 30s around DRT would suggest
they`ll have a hard time getting any low clouds that far west. The
dry air and good daytime mixing should start clearing things up by
around 16Z with afternoon westerly winds and gusts becoming the main
concerns in the latter part of the TAF periods.

&&

.FIRE WEATHER...
Issued at 304 AM CDT Wed Mar 12 2025

- Critical to extreme fire weather conditions today

- Another significant fire weather event expected Friday & Saturday
with possibly more impacts farther east

A dryline advancing eastward Wednesday morning quickly becomes
overtaken by a Pacific front by mid-afternoon. Critical to extreme
fire weather conditions develop, especially in the immediate wake of
where these boundaries merge. Strongest winds of 20-30 mph with
gusts to 45 mph will be combined with RH values in the 8-15% range,
mainly north and west of a line from Eagle Pass to Kerrville to
Llano. Just south and east of this, line, the winds could still gust
to 30 to 40 mph, and with slightly higher RH values mainly 10-20%.

The progression of mainly just the Pacific front will enter the I-35
corridor counties and impact the area for the first few hours of the
evening. The dry air will continue overtaking the area overnight,
but the winds are expected to drop off considerably after dark.

Confidence is very high (90-100%) in critical fire weather
conditions occurring across the southern Edwards Plateau, Rio
Grande, and Hill Country where the Red Flag Warning timing begins at
noon. By 4 PM, the confidence in knowing how far east the front is
to advance comes into play leaving the confidence in the I-35
corridor counties slightly reduced to medium (30-60%), with a
sharply rising RH gradient east of I-35. We have included the I-35
counties in a short-period Red Flag Warning for the late
afternoon/early evening.

A series of upper level systems helps to generate critical fire
weather conditions over the region both Friday and Saturday. The
strongest winds on Friday behind the combo of a dryline and Pacific
front should focus across the northern half of the area. However,
for Saturday, the strong westerly winds will be more centrally
located and will trend more widespread across the region. In
general, sustained winds 20 to 30 mph will be common with higher
gusts into the 45 mph range. These speeds could be a little
conservative, especially on Saturday, and may continue to rise as
these events get closer in time. The minimum relative humidity
levels fall to the 5 to 15 percent for majority of the area both
days as well. Anticipate Fire Weather Watches and/or Red Flag
Warnings in upcoming forecast cycles.

Winds decrease into Sunday and Sunday night across the region but
enough winds still may overlap with lower humidity near the Rio
Grande for elevated fire weather. The winds then shift and uptick
out of the south through early next week. There could still be
enough overlap with some lower humidity values across portions of
the region to result in possible elevated to near critical fire
weather. Wednesday could see an increase in the fire weather with
the passing of another storm system towards the north and with
arrival of a front into the area.


&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              90  56  91  62 /  10   0   0   0
Austin Bergstrom Intl Airport  89  51  90  59 /  10   0   0   0
New Braunfels Muni Airport     90  53  92  59 /  10   0   0   0
Burnet Muni Airport            89  52  88  61 /   0   0   0   0
Del Rio Intl Airport           93  54  93  61 /   0   0   0   0
Georgetown Muni Airport        89  56  89  61 /  10   0   0   0
Hondo Muni Airport             92  48  92  57 /   0   0   0   0
San Marcos Muni Airport        89  53  90  58 /  10   0   0   0
La Grange - Fayette Regional   86  54  90  60 /  10  10   0   0
San Antonio Intl Airport       90  53  91  61 /   0   0   0   0
Stinson Muni Airport           92  51  92  60 /   0   0   0   0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 1 PM this afternoon to 8 PM CDT this evening for
Edwards-Gillespie-Kerr-Kinney-Llano-Maverick-Real-Val Verde.

&&

$$

Short-Term...18
Long-Term...Brady
Aviation...18