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

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FXUS64 KEWX 210533

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1233 AM CDT Mon Oct 21 2019

A few gusts to as high as 22 knots are feeding in the direction of an
approaching squall line. MVFR skies are most common, but a small
period of IFR cigs are expected just before the front driven squall
reaches the I-35 corridor. Squall line along and just ahead of a
cold front was noted from Junction to near Stephenville at 0530Z. The
front will be the leading edge of the deeper convection by the time
it descends on the metro cities, reaching AUS by 09Z and SAT/SSF at
11-1130Z. The deeper convection should last no more than 2 hours with
vfr skies quick to replace the rains. No significant convection is
currently expected to impact DRT. Some gusty conditions behind the
front could last about 4-6 hours, but models are quick to show
lighter winds in the afternoon.


.PREV DISCUSSION... /ISSUED 706 PM CDT Sun Oct 20 2019/

Isolated thunderstorms are moving toward the north east of AUS. These
storms should stay east of AUS as they continue for the next hour or
two. All terminals are VFR at this time. MVFR ceilings will develop
in the Austin and San Antonio areas later this evening and continue
overnight. A cold front will move through the region early Monday and
showers and thunderstorms Monday morning to Austin and San Antonio
and a chance at DRT. Rain chances will end by around noon. VFR
conditions will prevail Monday afternoon.

PREV DISCUSSION... /ISSUED 259 PM CDT Sun Oct 20 2019/

SHORT TERM (Tonight through Monday Night)...
The main story of the short term will be the cold front expected
through tonight into tomorrow morning. Ahead of the front another
warm afternoon is producing more record high temperatures. Just like
yesterday the warm afternoon temperatures and abundant moisture could
spark off a few late afternoon showers and thunderstorms east of the
I-35 corridor. The Texas Tech WRF and last few runs of the HRRR have
consistently shown this activity along and east of I-35 late this
afternoon into the evening hours.

Based on the latest high resolution models the front should arrive
across the Edwards Plateau and Hill Country early Monday morning
(between 2-4am), moving into the I-35 corridor between 5-7am, and
then south through the Coastal Plains by 10am. While the best upper
level jet dynamics will remain north of the area across North Texas
and Oklahoma, where SPC has an enhanced risk of severe weather,
decent CAPE and modest shear will create a small window for some
strong, and possibly a severe storm or two across the area. The main
threats will be some hail (best chances across the Hill Country early
Monday morning), and damaging winds (anywhere along the broken line
of storms). Because of this SPC does have parts of the Hill Country
and Coastal Plains in either a Day 1 or Day 2 Marginal risk. High
resolution models depict a broken line of showers and storms moving
through the area. Any of these could produce a brief heavier shower,
but general rainfall amounts should be light. The time of day (early
morning through morning hours) should also help keep the severe risk
down to just the few strong to severe storms like we saw with the
last front.

The front will quickly clear the area through the day with drier and
cooler air filtering in behind it. Sunny skies should return by
Monday afternoon with winds out of the north between 10-15 mph. Highs
tomorrow should hold in the upper 70s to lower 80s, a good 10-15
degrees cooler than highs today. Because of the drier air and
decent post frontal winds elevated fire weather will be a concern
across the Rio Grande Plains and Edwards Plateau during the
afternoon hours on Monday.

LONG TERM (Tuesday through Sunday)...
Tuesday and Wednesday will generally be mostly sunny and seasonable
across South Central Texas. Afternoon highs will be near normal for
mid to late October in the upper 70s and lower 80s. While Tuesday
will see light winds and dry air remaining in place, southerly flow
will make a return on Wednesday hastening the return of Gulf of
Mexico moisture ahead of the next cold front.

Models are still in vast disagreement with the timing of the large
upper trough and cold front for Thursday. The GFS remains the most
progressive of the models having a large upper trough across the
Plains and a cold front that arrives mid-day on Thursday. The 12z
ECMWF and 12z Canadian continued the trend of their 00z runs and
remain deeper and slower with the trough and thereby are slower with
the front. The Canadian is a nice compromise between the extremes of
the GFS and ECMWF at this point, bringing the front through Thursday
evening, with the ECMWF moving it across the area Thursday night into
Friday. Regardless of the timing the front, which looks stronger than
the front moving through tonight, should bring another good shot of
rain for most areas along with much cooler temperatures. Highs Friday
should struggle to get out of the mid 60s, and by Saturday they will
only reach into the upper 60s to near 70. This means overnight lows
in the 40s for Friday through Sunday morning. One important note
about the ECMWF and Canadian solutions is they keep the upper trough
across north Texas into the weekend, which if it verifies would keep
rain chances around behind the front.


Austin Camp Mabry              53  80  54  82  63 /   0   0   0   0  10
Austin Bergstrom Intl Airport  49  80  51  82  61 /   0   0   0   0  10
New Braunfels Muni Airport     51  80  52  82  62 /   0   0   0  -   10
Burnet Muni Airport            50  77  51  79  60 /   0   0   0   0  10
Del Rio Intl Airport           52  84  56  84  64 /   0   0   0   0  -
Georgetown Muni Airport        49  78  52  81  61 /   0   0   0   0  10
Hondo Muni Airport             50  83  54  85  64 /   0   0   0   0  -
San Marcos Muni Airport        51  80  52  82  61 /   0   0   0  -   10
La Grange - Fayette Regional   50  80  52  82  63 /   0   0   0  -   10
San Antonio Intl Airport       53  80  55  82  65 /   0   0   0  -   10
Stinson Muni Airport           53  81  55  83  65 /   0   0   0  -   -




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