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

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FXUS64 KEWX 180454
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1054 PM CST Sun Dec 17 2017

.AVIATION... /06Z TAFS/

Areas of dense fog are developing outside the vcnty of the TAF sites
and the overall trends are downward with cigs and vsbys. Will
maintain several hours of vlifr conditions with a Dense Fog Advisory
already in effect for all of South Central TX. Guidance trends also
shifted toward several hours of low cigs with 1/4-1/2SM vsbys. At
this rate do not expect to see any locations with a vfr sky on monday
with the maximum mixing in the midday hours to improve to a low end
mvfr cig at best. For tomorrow night, the pattern becomes potentially
more convective with some scattered showers in the area, so will
stay with a prolonged period of low end ifr cigs.

&&

.PREV DISCUSSION... /ISSUED 956 PM CST Sun Dec 17 2017/

UPDATE...
Dense fog is beginning to develop across South Central Texas as T/DP
spreads lower to Zero with light or calm winds. Expect dense fog to
become more widespread overnight with near zero T/DP spread and light
or calm winds most areas. Have issued a Dense Fog Advisory for all
of our area through 9 AM. It`s possible that it may have to extended
in time for some spots. Temperatures will remain nearly steady,
fluctuating a degree or two overnight into the morning. Have also
expanded patchy drizzle to all areas in favor of showers. Remainder
of forecast is on track.

PREV DISCUSSION... /ISSUED 303 PM CST Sun Dec 17 2017/

SHORT TERM (Tonight through Monday Night)...
Much of the area will continue under cloudy skies as eastern Pacific
moisture pushes from the southwest into South Central Texas.
Temperatures are expected to remain relative warm this evening and
overnight for the potential of patchy to areas of fog developing
around midnight tonight through about 9 or 10 am Monday. Can`t rule
out some areas with dense fog around dawn. With abundant moisture in
place and an upper level pressure system over the four corners
region late tonight moving slowly to the east and into west Texas,
expect drizzle to light rain across the eastern two-thirds of South
Central Texas Monday morning in addition to foggy conditions.

As the upper system moves to the east throughout the day, scattered
showers and even isolated thunderstorms are expected mainly east of
Highway 83 (east of a Leakey to Carrizo Springs line).

The activity is expected to pick up as well as storm`s intensity
later Monday night into Tuesday as the upper level disturbance moves
into the southern Plains. A low level jet of 40 to 50 knots will
allow storms to quickly develop and become strong to even severe.
Main weather hazard could be damaging gusty winds.

Rainfall amounts for the period could range from one half to an inch
mainly along and east of Highway 77.

LONG TERM (Tuesday through Sunday)...
The strong to severe weather threat continues for much of Tuesday and
mainly along and east of Highway 77. The upper level disturbance
finally lifts and pushes to the east late Tuesday afternoon with dry
weather conditions and a warmer trend for Wednesday and Thursday.

Chances for rain return on Friday ahead and along a cold front with
rain coming to an end by Friday night. The latest runs of medium-
range models show warmer temperatures and relative dry weather
conditions for next weekend. Still to many model runs to go and
solutions can chance back to earlier solutions. Therefore, continue
to monitor our website for the latest forecast packages as you plan
for the Christmas holiday weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              50  60  57  68  50 /  10  40  60  80  10
Austin Bergstrom Intl Airport  50  61  57  69  49 /  10  40  60  80  10
New Braunfels Muni Airport     49  62  57  69  49 /  10  40  60  80  10
Burnet Muni Airport            49  59  54  64  46 /  10  40  50  80  10
Del Rio Intl Airport           48  62  53  69  45 /  10  10  30  30   0
Georgetown Muni Airport        49  59  56  66  49 /  10  40  50  80  10
Hondo Muni Airport             49  63  57  70  46 /  10  20  50  60  10
San Marcos Muni Airport        49  61  58  69  49 /  10  40  60  80  10
La Grange - Fayette Regional   52  64  60  74  54 /  10  40  70  80  30
San Antonio Intl Airport       50  63  58  69  50 /  10  30  60  70  10
Stinson Muni Airport           49  63  59  70  49 /  10  30  60  70  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM CST Monday for the following
counties: Atascosa...Bandera...Bastrop...Bexar...Blanco...Burnet...
Caldwell...Comal...De Witt...Dimmit...Edwards...Fayette...Frio...
Gillespie...Gonzales...Guadalupe...Hays...Karnes...Kendall...Kerr...
Kinney...Lavaca...Lee...Llano...Maverick...Medina...Real...Travis...
Uvalde...Val Verde...Williamson...Wilson...Zavala.

&&

$$

Mesoscale/Aviation...Oaks
Synoptic/Grids...04
Public Service/Data Collection...YB



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