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

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FXUS64 KEWX 201149 AAA

Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
649 AM CDT Tue Oct 20 2020

/12Z TAFS/
Flying categories will go back and forth between VFR and MVFR this
morning. As earlier mentioned below, low level clouds are covering
most of the area and continue to expand across the Rio Grande area.
Also, a few lines of light showers pushing from the south and between
Highway 281 and Highway 183 could move over the I-35 terminals this
morning and have included VCSH for KAUS, KSAT and KSSF through late
this morning. VFR cigs return late this morning/early this afternoon
across area airports. Winds will be from the south through the period
and averaging 5 to 10 knots across the I-35 corridor and 10 to 15
knots with higher gusts along KDRT where a stronger low level jet
is situated. MVFR cigs come back late tonight across area terminals
with even IFR conditions possible overnight along the I-35 airports.


.PREV DISCUSSION... /ISSUED 335 AM CDT Tue Oct 20 2020/

SHORT TERM (Today through Wednesday)...
Low clouds are covering the eastern two-thirds of South Central
Texas while expanding to the west into the Edwards Plateau area per
latest satellite images. These clouds are expected to linger around
through mid-day when partly cloudy skies begin to dominate the area.
Based on HiRes solutions and SPC Mesoanalysis parameters, especially
the precipitable water and precipitation potential placement maps,
have decided to add a 20 percent chance for rain showers for the
morning period mainly over areas between Highway 83 and highway 183.
If these showers develop and you are the lucky one, estimated
rainfall amounts range from a trace to a tenth of an inch.
Otherwise, expect above normal high temperatures ranging from the
mid 80s across the Hill Country to lower 90s across the Rio Grande.
Southerly winds will persist throughout the day around 5 to 10 mph
across most areas with 10 to 15 mph and higher gusts along the Rio
Grande as low level winds are forecast to be stronger there due a
tighter pressure gradient between 950-850 mb layer, which ultimately
mixes to the surface.

Increased moisture return tonight into Wednesday with cloudy skies
expected across most of South Central Texas. Overnight lows are
forecast to be in the mid 60s to lower 70s range. After a cloudy
start of the day on Wednesday, clouds will give way to mostly sunny
skies in the afternoon with highs in the mid to upper 80s.

LONG TERM (Wednesday Night through Monday)...
Look for a continuation of warm temperatures and periods of late
night through morning low clouds across south central Texas for
Thursday. Highs will be in the 80s along with overnight lows in the
lower 60s to near 70. While we can`t completely rule out a stray
shower or two during the early morning hours, the vast majority of
the region will remain dry. We also kept a low chance for afternoon
showers and thunderstorms near the coastal plains, but confidence is
fairly low.

A cold front will move in Friday afternoon/evening, resulting in a
slight cool down for areas along and north of a Rocksprings to
Georgetown line. Elsewhere, the cold front will likely be too late to
have an impact on highs and we should see mid 80s to lower 90s here.
As of now, we will not include a chance for rain with the passage of
this cold front. With weak upper support moving east of the region
and no significant forcing along the boundary, prefer to keep the
forecast dry at this time. Cooler and dry air will work southward
Friday night into Saturday, with lows in the lower 50s to lower 60s
and highs in the mid 70s to mid 80s.

Southerly flow in the low-levels quickly returns on Sunday resulting
in a warm-up back to above normal temperatures. It appears the above
normal warmth will be short-lived as a fairly stout cold front moves
through Monday. The front will be moving into our region during the
daytime hours and this will have an impact on high temperatures
Monday, especially across the Hill Country. For now, we prefer the
faster model solutions given there will be a decent amount of cold
air with this front. We will also include 20-30% chance for showers
and thunderstorms for most of the region on Monday as the medium
range models show an upper level trough approaching from the west
late Monday. There are model differences with regards to the timing
and strength of upper support associated with this trough. For now,
we prefer to keep rain chances on the low side as the latest data
keeps the stronger forcing for ascent to our north.


Austin Camp Mabry              87  70  86  67  86 /   0   0  -    0  -
Austin Bergstrom Intl Airport  88  69  86  66  87 /  -    0  -    0  -
New Braunfels Muni Airport     90  70  89  69  89 /  20  -   10   0  -
Burnet Muni Airport            86  67  84  66  85 /  20   0  -    0   0
Del Rio Intl Airport           90  70  89  69  90 /   0  -    0   0   0
Georgetown Muni Airport        87  68  86  66  85 /  10   0  -    0  -
Hondo Muni Airport             90  67  89  67  90 /  20  -   -    0   0
San Marcos Muni Airport        88  68  87  66  87 /  -    0  10   0  -
La Grange - Fayette Regional   89  70  88  68  88 /   0   0  10   0  -
San Antonio Intl Airport       88  70  87  68  88 /  20  -   10  -   -
Stinson Muni Airport           89  69  87  68  88 /  20  -   10   0  -




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