Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 01/31/21
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
957 PM CST Sat Jan 30 2021
.UPDATE...
We just sent an update to re-trend forecast variables through 12Z
Sunday. Those living along and north of I-10 will see reduced
visibility to 3 to 5 miles due to blowing dust coming southeast from
West Texas. The dust should settle down by 3 am.
&&
.PREV DISCUSSION... /ISSUED 536 PM CST Sat Jan 30 2021/
AVIATION...
High pressure will continue to build into the area over the next 30
hours. In general, expect CAVU with clear skies and light to moderate
winds. However, there are some complications. In the very short term
(00-06Z), there is a dust plume moving south from west Texas.
Trajectories indicate it will likely miss the TAF sites, but
departure and approach from KAUS to the northwest should expect some
VSBY restrictions 2-4SM BLDU in the lowest 1-2 kft AGL. Later on from
06Z-15Z, models indicate areas of LLWS in VCNTY of KAUS. Not severe
or consistent enough to include in the TAF, but again, aircraft
approaching or departing KAUS should be aware of LLWS in the lowest 2
kft. After 15Z Sunday, daytime heating and mixing will bring
stronger winds to the surface, so expect at least 10G20KT areawide,
and 15G25KT in the VCNTY of KAUS.
PREV DISCUSSION... /ISSUED 205 PM CST Sat Jan 30 2021/
SHORT TERM (Tonight through Sunday Night)...
A quiet, mostly clear, and fairly seasonable short term is in store.
The cold front is currently moving across South Central Texas this
afternoon. Skies have cleared along and west of the I-35 corridor,
but should continue to clear through the afternoon area for those
folks to the east of Interstate 35. Despite models still showing the
front slowly as it progresses eastward, breaks in the stratus deck
are already evident in the GOES-16 visible satellite data. Behind
the front elevated to near critical fire weather will be possible
across the Hill Country, Edwards Plateau, and Rio Grande this
afternoon. We are already seeing relative humidity values fall into
the 20 to 30 percent range with some gusty winds between 15 and 25
mph.
Winds will calm down overnight out of the northwest, but the
combination of continued 5 to 10 mph winds and a more mild initial
airmass out of the west will keep overnight lows in the low to upper
40s across the area. A reinforcing boundary will sweep across the
area tomorrow afternoon leading to another breezy to windy afternoon
with winds becoming more northerly. Finally some slightly cooler,
not just drier air will move in, resulting in highs tomorrow topping
out a good 5 to 10 degrees cooler than they were today. While
cooler, these afternoon highs will still be running a good 2 to 8
degrees above seasonal normals for the end of January. As winds
subside again Sunday night the cooler airmass will take hold. While
no freezing temperatures are currently forecast mid 30s across the
Edwards Plateau and Hill Country are expected, with upper 30s to
near 40s elsewhere.
LONG TERM (Monday through Saturday)...
Quiet weather pattern will continue for the first half of the long
term period. Upper level ridge of high pressure centered over Central
Mexico will extend into the Central CONUS. Southeasterly surface
winds return by Tuesday morning, bringing with it Gulf moisture.
Ridge axis just to our west will kick off a warming trend, sending
afternoon high temperatures for Wednesday and Thursday into the upper
70s to mid 80s for much of the region. Well above normal for the first
week of February.
By Thursday, upper level pattern flattens to a mostly zonal flow
ahead of an approaching trough out of Southern California. Models
diverge on the timing of this next system which has implications for
the end of the forecast period. Referencing the latest suite of
models, the ECM is the most progressive with this system and digs
slightly farther south. GFS lags about 6 hours behind the ECM and
keeps the vort max associated with the trough further to the north.
The difference in placement of this feature results in the ECM being
slightly wetter with QPF through Thursday of about 1/3" for portions
of the Hill Country and northern I-35 corridor. The GFS for the same
time period has a few hundredths for those same areas. The CMC takes
this feature as a cut off low way farther south into Mexico and moves
out of the mean flow and stalls while a longwave trough becomes the
prominent feature across much of the CONUS. All of this to say,
there is quiet the disagreement among the models and details have to
be worked out for this next system. Regardless, South-Central Texas
can expect a front moving across the area sometime between Thursday
evening into Friday late morning. Slight chances for rain is in the
forecast for Friday with the passage of the associated front for
northeastern areas including a good portion of the I-35 corridor.
Beyond Friday, cooler airmass settles in and upper level troughing
remains in place over the Central CONUS.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 47 67 40 64 36 / 0 0 0 0 0
Austin Bergstrom Intl Airport 47 67 38 65 34 / 0 0 0 0 0
New Braunfels Muni Airport 47 72 40 68 36 / 0 0 0 0 0
Burnet Muni Airport 44 64 37 64 35 / 0 0 0 0 0
Del Rio Intl Airport 47 73 40 68 41 / 0 0 0 0 0
Georgetown Muni Airport 46 64 37 63 35 / 0 0 0 0 0
Hondo Muni Airport 44 74 38 68 35 / 0 0 0 0 0
San Marcos Muni Airport 46 70 38 66 34 / 0 0 0 0 0
La Grange - Fayette Regional 47 67 40 64 35 / 0 0 0 0 0
San Antonio Intl Airport 49 70 42 67 38 / 0 0 0 0 0
Stinson Muni Airport 48 72 41 67 37 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...Zeitler
Long-Term...Runyen