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

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FXUS64 KEWX 150443

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1043 PM CST Thu Feb 14 2019

The wind forecast will be the only item of note in the aviation
forecast world across South Central Texas through the TAF period as
the SCT/BKN VFR deck of cloud cover continues. Winds tonight will be
light and variable before increasing tomorrow out of the southwest
around 10 knots. A few gusts will be possible at AUS during the day.
Winds will become northerly at DRT around 19z tomorrow afternoon, but
the windshift won`t work into the I-35 terminals until around 06z on
the 16th (around midnight Friday going into Saturday). While the
direction will change from southwesterly to northerly speeds will
only increase to around 10 knots as VFR conditions continue.


.PREV DISCUSSION... /ISSUED 1000 PM CST Thu Feb 14 2019/

Areas from the Hill Country to the Rio Grande Plains are running
cooler than forecast due to lower dewpoints and lighter winds. Have
gone a little cooler for low temperatures tonight in those areas.
Have also gone a little drier on dewpoints for those areas as
minimal moisture advection is expected tonight and westerly lower
level flow keeps them drier Friday. Elevated fire weather conditions
continue to be possible across the Hill Country to the Rio Grande
due to humidities in the 20s and westerly winds of 10 to 20 mph in
the afternoon. However, fuel moistures are normal to above normal.
Early evening model runs continue to indicate a cold frontal passage
into parts of our area Friday night into Saturday, then oscillating
Sunday before finally plunging south by Monday. The most impacted
weekend temperature forecasts will be across our Central Texas to
along and east of I-35 to the upper Texas Coastal Plains counties.

PREV DISCUSSION... /ISSUED 318 PM CST Thu Feb 14 2019/

SHORT TERM (Tonight through Friday Night)...
Afternoon visible satellite imagery shows a broken cirrus canopy
streaming across the region from the northwest, where upper level
winds are continuing to transport moisture from the Pacific. Expect
these high clouds to persist through the overnight hours with light
southerly winds and modest radiational cooling allowing for patchy
fog to develop along and east of an Eagle Pass to San Antonio to
Austin line. Fog may linger into the mid-morning hours before
insolation and daytime mixing clear the fog out.

After a mild start in the low to mid 50s, low level winds
strengthening and veering to the west/northwest ahead of a cold front
now oozing through Kansas will produce strong compressional warming
across the region during the day. This will mean record heat is on
tap on Friday with highs soaring into the 80s to near 90. A listing
of these climate records for South Central Texas is provided in the
climate section below.

Dry conditions will continue across the region Friday as the cold
front makes slow progress across the Southern Plains, creeping across
North Texas on Friday night. Forecast soundings show that this front
looks to be very shallow, maybe 700 feet deep, as it approaches the
region and this will mean that the density differences between the
pre and post-frontal airmasses will be a big driver in how far south
the front pushes Friday night. Despite this shallow nature of the
cold front, global and higher resolution guidance is actually in
remarkably good agreement on the front pushing into Central Texas by
sunrise. As a result, lows Friday night are expected to range from
the mid 40s in Central Texas to the low 60s in the Rio Grande Plains.

LONG TERM (Saturday through Thursday)...
Insolation on Saturday will allow for some modification of the post-
frontal airmass on Saturday, resulting in the frontal boundary
stalling somewhere near the Interstate 10 corridor during the day.
This will result in a stark temperature contrast across the region
with near normal temperatures in the mid 60s behind the front in
Central Texas and highs in the mid 70s to low 80s ahead of the cold
front across the rest of the region. Because high temperatures on
Saturday are so heavily dependent on the location of this front,
overall confidence in temperatures on Saturday are low. The good news
is that atmospheric moisture looks too low to produce any kind of
rain as the front approaches, leaving temperatures as the main
weather story on Saturday.

A few light showers may be possible within the vicinity of the cold
front Saturday night through Sunday across the Coastal Plains as it
lingers along the coast and some weak overrunning develops. Lows in
the mid 40s to low 60s Saturday night are expected to warm into the
upper 60s to upper 70s on Sunday. A more active pattern sets up for
South Central Texas Monday through Thursday as longwave troughing
over the western CONUS results in persistent southwest flow aloft
across the region. This allow for smaller disturbances embedded in
this flow aloft to translate across the region and aid in a series of
reinforcing cold fronts, resulting in periods of showers and near to
below normal temperatures.

Record high temperatures are possible at the South Central Texas
climate sites on February 15 and 16. A listing of these records are
provided below.

Austin Bergstrom          83         1980
Austin Camp Mabry         85         1980
San Antonio               85         1990
Del Rio                   87         1990

Austin Bergstrom          83         2006
Austin Camp Mabry         84         1982
San Antonio               87         1927
Del Rio                   87         2006


Austin Camp Mabry              75  53  86  51  71 /   0   0   0   0   0
Austin Bergstrom Intl Airport  75  52  86  51  71 /   0   0   0   0   0
New Braunfels Muni Airport     74  51  85  51  73 /   0   0   0   0   0
Burnet Muni Airport            75  51  85  46  69 /   0   0   0   0   0
Del Rio Intl Airport           77  50  89  55  83 /   0   0   0   0   0
Georgetown Muni Airport        75  52  86  46  66 /   0   0   0   0   0
Hondo Muni Airport             72  49  87  54  80 /   0   0   0   0   0
San Marcos Muni Airport        73  52  84  52  71 /   0   0   0   0   0
La Grange - Fayette Regional   76  57  80  52  69 /   0   0   0   0   0
San Antonio Intl Airport       70  50  86  54  76 /   0   0   0   0   0
Stinson Muni Airport           74  50  86  54  77 /   0   0   0   0   0




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