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

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FXUS64 KEWX 150400

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

The main aviation story for this TAF period remains to be the wind as
SCT to OVC ceilings will remain at VFR levels through the period.
Winds at AUS and all other terminals will decrease through the
evening and be between 5-10 knots overnight out of the southwest.
They will pick up again tomorrow afternoon to around 10 to 12 knots,
with some gusts possible during the afternoon hours at AUS out of the
west. A windshift will work into DRT Friday afternoon as well with
winds shifting to be more out of the northwest.

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              53  86  51  71  57 /   0   0   0   0  10
Austin Bergstrom Intl Airport  52  86  51  71  58 /   0   0   0   0  10
New Braunfels Muni Airport     51  85  51  73  59 /   0   0   0   0  10
Burnet Muni Airport            51  85  46  69  53 /   0   0   0   0  -
Del Rio Intl Airport           50  89  55  83  57 /   0   0   0   0   0
Georgetown Muni Airport        52  86  46  66  54 /   0   0   0   0  10
Hondo Muni Airport             49  87  54  80  59 /   0   0   0   0  -
San Marcos Muni Airport        52  84  52  71  58 /   0   0   0   0  10
La Grange - Fayette Regional   57  80  52  69  61 /   0   0   0   0  20
San Antonio Intl Airport       50  86  54  76  60 /   0   0   0   0  10
Stinson Muni Airport           50  86  54  77  61 /   0   0   0   0  10




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