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Area forecast discussion
National Weather Service Austin/San Antonio Texas
1008 am CST Mon Dec 9 2019

Update...
visibility has improved across the area and we have allowed the dense
fog advisory to expire. A few places may still have visibility of 1/4
mile or less for another hour or so.

&&

Previous discussion... /issued 612 am CST Mon Dec 9 2019/

Update...
a dense fog advisory has been issued for portions of south central
Texas until 10 am CST. The advisory area does cover Hondo, San
Antonio, New Braunfels and San Marcos. We will continue to monitor
the fog and will add additional counties if needed.

Previous discussion... /issued 529 am CST Mon Dec 9 2019/

Aviation...
LIFR ceilings have developed along with areas of dense fog for the
I-35 sites. Low stratus and fog are expected to gradually erode by
15-18z Mon, brief MVFR ceilings, then VFR conditions for the
afternoon. Cold front will move over the area Monday night, reaching
aus/drt around 03z Tue and Sat/ssf 05z Tue. Vcsh for frontal passage
and continues through the remainder of the period.

Previous discussion... /issued 401 am CST Mon Dec 9 2019/

Short term (today through tuesday)...
surface observations from early this morning show fog is developing
generally along and east of the I-35 corridor. Some locally dense fog
can not be ruled out this morning and we will continue to monitor
trends. With winds being lighter along and south of the Highway 90
corridor, the lower visibilities should be favored from the San
Antonio area east and south into the coastal plains. However, we are
seeing plenty of mid and high level cloud cover move in from the
west. This along with some stronger winds just above the surface will
tend to disrupt widespread dense fog development. Once the fog Burns
off by late morning, we expect a warm day across south central Texas
with highs in the mid 70s to lower 80s. Some records may be met or
exceeded, with our current forecast showing records being tied at
Austin Bergstrom and Austin Mabry, with del Rio expected to break the
current record high. Please see the below climate section for more
information.

We still expect a significant change in the weather tonight as a
strong cold front moves through the region. With warm air advection
above the shallow cold air mass, light rain is expected to develop
this evening, then increase overnight as the cold air deepens.
Rain chances on Tuesday remain high through the morning hours, but
will decrease from west to east in the afternoon as the warm air
advection pattern begins to shut off. Average rainfall amounts
tonight through Tuesday are still expected to remain near or below
1/4".

Long term (tuesday night through sunday)...
cool and dry weather can be expected Tuesday night through Thursday
with surface high pressure generally in control of our weather.
Overnight lows are expected to drop to at or below freezing for The
Hill Country and adjacent I-35 Corridor North of San Antonio Tuesday
night/Wednesday morning and again Wednesday night/Thursday morning. We
will see another upper level system move in from the west late
Thursday, but the models continue to remain in some disagreement on
the path of this upper trough. As of now, it does not appear we will
see any rain chances with this next upper system and will keep the
forecast dry through the end of the work week.

Temperatures will warm Friday through Sunday with dry and stable
westerly flow aloft over the region. Highs will return to the 60s and
70s with lows in the 40s and 50s.

Climate...
December 9
location record high (year)
Austin Bergstrom 81 (2008)
Austin Camp Mabry 81 (2008)
San Antonio 85 (2008)
del Rio 80 (2004)

&&

Preliminary point temps/pops...
Austin Camp Mabry 81 42 46 33 56 / 0 70 90 - -
Austin Bergstrom Intl Airport 81 42 45 31 57 / 0 70 90 - -
New Braunfels Muni Airport 79 43 47 32 57 / 0 70 90 - -
Burnet Muni Airport 79 39 44 29 54 / 0 80 100 - -
del Rio Intl Airport 81 49 54 37 59 / 0 70 60 0 0
Georgetown Muni Airport 81 40 44 30 55 / 0 80 100 - -
Hondo Muni Airport 81 46 53 32 60 / 0 70 70 - -
San Marcos Muni Airport 80 43 47 31 57 / 0 70 90 - -
La Grange - Fayette regional 81 44 48 34 56 / 0 80 90 10 10
San Antonio Intl Airport 78 45 48 34 57 / 0 70 80 - 10
Stinson Muni Airport 80 47 50 35 58 / 0 70 80 - 10

&&

Ewx watches/warnings/advisories...
none.
&&

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