Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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FXUS64 KEWX 281131

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
531 AM CST Fri Feb 28 2020

VFR conditions will prevail today and tonight with thin cirrus
streaming through the region. A weak surface trough will clip
Central Texas later this morning with a brief, weak wind shift to
the northwest behind it at AUS. Weak NW drainage wind around 5KT at
SAT early this morning is forecast to turn SW by midday and SE this
evening. NE wind around 5KT at DRT is forecast to turn southeast
midday and strengthen slightly.


.PREV DISCUSSION... /ISSUED 326 AM CST Fri Feb 28 2020/

SHORT TERM (Today through Saturday)...
Dry northwest to west mid and upper level flow will prevail through
the short-term with periods of thin cirrus. A weak surface trough
will clip Central Texas later this morning with brief, weak wind
shift to the northwest behind it. Elsewhere, west to southwest winds
this mid to late morning should promote a quick warmup, given the
dry airmass in place. High temperatures today are forecast in the
upper 60s to low 70s central and eastern areas to mid 70s closer to
the Rio Grande. Low temperatures tonight modify slightly forecast
into the upper 30s to mid 40s. A southerly low level flow will
strengthen on Saturday, leading to breezy surface conditions by
afternoon. Afternoon high temperatures on Saturday are forecast to
be in the mid 70s for many areas, with the exception of upper 60s to
low 70s across the Hill Country. The breezy winds and dry air in
place could lead to a period of elevated to near-critical fire
weather conditions Saturday afternoon across portions of South
Central Texas.

LONG TERM (Saturday Night through Thursday)...
With the surface high to the east across the north central Gulf of
Mexico and southerly flow continuing temperatures Saturday night and
on Sunday will continue to warm. The lows in the mid 50s and highs in
the upper 70s will be anywhere from 10 to 15 degrees above seasonal
normals. With the increased moisture at the surface morning stratus
will also make a return for Sunday morning. Sunday the next upper
level trough which will impact our weather for the beginning of the
work week will drop south across California and then begin to head
east towards Texas on Monday. With enough moisture in place a few
isolated showers could develop on Monday across areas east of I-35
under the inversion. The GFS has trended faster and further north
with the upper trough while the ECMWF and Canadian are all slower and
further south.

While the best chances of rain look to be Monday night through the
day on Tuesday there are decent disagreements in the models that go
beyond just the position of the upper trough. The GFS brings a
Pacific front across Texas by mid-day Tuesday, while this feature is
not shown in the ECMWF/Canadian. All 3 models have moved up the
timing of the stronger secondary front, with it arriving Tuesday
evening based on the ECMWF/Canadian and Tuesday night per the GFS.
The timing of the various fronts and the ultimate position of the
upper level trough will all play a role in the risk for strong thunderstorms
across South Central Texas. A slower solution with the secondary
front (like the GFS) leaves a window for some stronger storms to
develop on Tuesday afternoon with decent shear, modest instability,
and plenty of moisture and lift. If the secondary front is faster
that window for stronger storms shrinks.

The other thing the timing of the trough and front influence is the
amount of rainfall South Central Texas sees. The faster and drier GFS
only brings 1/4 to 3/4 of an inch to parts of the Edwards Plateau,
Hill Country, and points east. The slower ECMWF and Canadian both
have totals of 1 to 1.5 inches across parts of the area before the
trough exits the area mid to late Wednesday. For now the Wednesday
forecast is dry, giving the forecast nod to the GFS and NBM, but
should the trough slow any with the stronger front still in the area
rain chances could be extended into Wednesday which would increase
rainfall totals as well.

All models show a dry Wednesday night and Thursday with temperatures
cooling slightly, but remaining 2 to 5 degrees above normal.


Austin Camp Mabry              71  47  72  57  78 /   0   0   0   0   0
Austin Bergstrom Intl Airport  70  42  74  57  78 /   0   0   0   0   0
New Braunfels Muni Airport     71  42  73  55  78 /   0   0   0   0   0
Burnet Muni Airport            68  43  71  54  77 /   0   0   0   0   0
Del Rio Intl Airport           75  43  75  51  83 /   0   0   0   0   0
Georgetown Muni Airport        69  44  72  56  77 /   0   0   0   0   0
Hondo Muni Airport             73  40  75  51  81 /   0   0   0   0   0
San Marcos Muni Airport        71  42  73  55  78 /   0   0   0   0   0
La Grange - Fayette Regional   69  42  75  57  77 /   0   0   0   0  -
San Antonio Intl Airport       71  45  73  56  78 /   0   0   0   0   0
Stinson Muni Airport           72  43  74  56  80 /   0   0   0   0   0





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