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

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FXUS64 KEWX 221129

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
529 AM CST Sun Nov 22 2020

Seeing some patches to areas of fog with reduced visibilities this
morning, certainly not to the extent the previous two days have had.
Only sites right now dealing with reduced visibilities and LIFR
conditions is the San Antonio sites. Expect this to continue the next
couple of hours for SAT and SSF (vis remaining above 2SM) before
mixing out later this morning. Also seeing some weak returns on
radar. High resolution models continue weak streamer shower activity
for the next few hours and have added VCSH to the SAT and SSF TAFs to
cover this sporadic activity. A weak front will reach South-Central
Texas this afternoon and give a more easterly wind component. AUS
looks to be the only site that has a shot of a stray shower with this
front this afternoon. Anticipating another round of low stratus
overnight tonight with IFR/MVFR ceilings building in. Visibilities
shouldn`t be a concern for Monday morning due to drier dewpoints
filtering in. Wind shift will be short lived as southeasterly flow
returns Monday afternoon.


.PREV DISCUSSION... /ISSUED 348 AM CST Sun Nov 22 2020/

SHORT TERM (Today through Monday)...
Deep low level moisture remains pooled over South-Central Texas with
another round of fog expected early this morning for portions of the
Coastal Plains and Hill Country. Fog coverage shouldn`t be as
widespread due to low level stratus building in early last night and
visibilities should remain above 1-2 miles, could have some isolated
pockets of dense fog. High resolution models indicate the
possibility of light streamer shower activity for areas east of San
Antonio and south of Austin along I-35 and I-10, much like what this
same area saw yesterday.

Fog and any remaining streamer showers should mix out by late
morning and afternoon temperatures will once again climb above climo
norms. While a front is expected to at least make it into portions
of South-Central Texas, this boundary isn`t expected until the
afternoon hours (19-21Z) and should only have a minor impact on
today`s max temperatures. Model consensus has this boundary
dissipating as it makes it`s way over the Hill Country and south of
the Austin metro. Only a temporary wind shift to the east to
northeast for much of the area and very sparse shower coverage for
our northeastern tier of counties. We will see slightly drier
dewpoints filter in throughout the evening hours and should see
overnight lows about 10 degrees cooler than last night`s lows for
the northeastern half of the CWA.

Slightly cooler temperatures for Monday thanks to the washed out
front and residual northeasterly wind. It will be short lived as
winds turn back to the southeast Monday afternoon and shortwave
ridging begins to build back in over South-Central Texas.

LONG TERM (Monday Night through Saturday)...
Surface high pressure east of the region along with a strengthening
lee-side trough will bring a quick return of southerly low-level flow
to south central Texas beginning Monday night. Overnight lows will
begin to trend upward, with most areas in the 60s. Southerly flow
strengthens Tuesday for breezy conditions and highs in the mid 70s to
mid 80s. We do expect the southwest flow aloft to increase on Tuesday as
an upper low moves across the southern plains states. We will see a
cold front accompany this upper low, with the front moving in late
Tuesday night or early Wednesday morning. With most of the lift
focused well north of the region, we will only mention a 20-30%
chance for showers and thunderstorms for areas generally north of a
Llano to San Marcos to Hallettsville line.

Temperatures will cool slightly on Wednesday with highs in the upper
60s to upper 70s. Southerly flow in the low-levels quickly returns on
Thanksgiving Day, signaling a warm-up for the region. Partly cloudy
skies along with highs mainly in the 70s can be expected on Thursday.
We also expect to see an increasingly active southwest flow aloft to
develop late Thursday through Saturday as an upper level trough, or
possibly closed low, develops and moves into the southern U.S. While
there continues to be some disagreement among the models in handling
the speed and strength of this system, we should see enough moisture
and lift to warrant a mention of rain for most of south central Texas
late in the forecast period. As of now, it looks like late Friday
will be favored as a fairly stout cold front move into the region.
Similar to previous forecasters here, we will not go too high with
our rain chances just yet as confidence is not terribly high in model
performance that far out. Temperatures should finally cool off to
below normal on Saturday with highs mainly in the 60s.


Austin Camp Mabry              74  52  71  61  80 /  20  -    0  -   -
Austin Bergstrom Intl Airport  75  52  73  60  81 /  20  -    0  -   -
New Braunfels Muni Airport     79  56  76  63  82 /  20  -    0  -    0
Burnet Muni Airport            73  50  68  59  77 /  20  -    0  -   -
Del Rio Intl Airport           79  60  76  62  84 /  -   20  10  -    0
Georgetown Muni Airport        74  50  69  59  78 /  20  -    0  -   -
Hondo Muni Airport             79  55  76  61  82 /  10  10   0  -    0
San Marcos Muni Airport        77  52  74  60  81 /  20  -    0  -   -
La Grange - Fayette Regional   79  55  76  61  82 /  20  -    0   0  10
San Antonio Intl Airport       79  56  75  62  80 /  20  -    0  10  -
Stinson Muni Airport           78  56  76  63  82 /  20  -    0  -   -




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