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

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FXUS64 KEWX 121748
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1148 AM CST Tue Dec 12 2017

.AVIATION.../18Z_TAFS/
VFR conditions are expected throughout the TAF period as strong N-NE
10-15 knot winds will continue this afternoon at the I-35 TAF sites
with gusts to 20-25 knots possible for the next few hours. Winds will
gradually subside this afternoon as the pressure gradient relaxes
and high pressure moves into the area. Winds tonight will be nearly
calm, but patchy fog is not expected as dew point depressions should
be too high. Winds will become southwesterly at the I-35 sites (and
SE at DRT) tomorrow around 10 knots ahead of a pre-frontal trough.

&&

.PREV DISCUSSION... /ISSUED 544 AM CST Tue Dec 12 2017/

AVIATION... /12Z TAFS/

Surface ridging behind this morning`s weak cold front could send
sustained winds to near 15 knots over Central TX with some afternoon
gusts over 20 knots possible. Most of the winds should sustain closer
to 10 to 12 knots and relax in the late afternoon. Light winds should
trend more from the west in the evening hours with light and variable
winds expected at DRT/SSF. No low or mid level cigs are expected
through the period.

PREV DISCUSSION... /ISSUED 306 AM CST Tue Dec 12 2017/

SHORT TERM (Today through Wednesday)...
An upper level trough moving across the Great Lakes and Mississippi
into Ohio Valleys will drag a cold front across our area early this
morning. No rain is expected as PWs near 1/4 inch are well below
normal. A fairly tight pressure gradient and some mixing from aloft
generate locally breezy conditions this morning into early afternoon.
Cold advection will drop high temperatures to near to slightly below
normal today. As a surface high settles in and winds aloft decrease,
winds subside rapidly by sunset and become light this evening into
overnight. Some cirrus passing overhead should not hamper efficient
radiational cooling and below normal low temperatures are expected
tonight. Surface high drifts off to the south on Wednesday turning
winds to southwesterly with highs around normal levels as weak upper
level ridging builds north from Mexico.

LONG TERM (Wednesday Night through Monday)...
An upper level shortwave rotates through the larger eastern states
upper level trough Thursday forcing another cold front across our
area. Again, no rain is expected as the airmass remains drier than
normal, though PWs are a little higher, around 1/2 inch. Locally
breezy conditions are possible due to fairly tight pressure gradient.
Slightly above normal temperatures on Thursday turn near to slightly
below normal on Friday as weak cold advection continues. Southerly
winds return with warm advection raising temperatures to above normal
Saturday. Models remain inconsistent for Saturday night into Sunday,
though ECMWF and GFS show some QPF for our area, but for different
reasons. The ECMWF has an upper level trough moving out of Mexico
while the GFS has an upper level trough moving across the Plains.
Have introduced slight chance POPs for areas east of I-35 for
Saturday night into Sunday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              63  37  67  44  65 /   0   0   0   0   0
Austin Bergstrom Intl Airport  63  35  65  41  65 /   0   0   0   0   0
New Braunfels Muni Airport     64  36  65  42  66 /   0   0   0   0   0
Burnet Muni Airport            60  35  67  40  61 /   0   0   0   0   0
Del Rio Intl Airport           66  38  66  42  67 /   0   0   0   0   0
Georgetown Muni Airport        61  35  67  42  63 /   0   0   0   0   0
Hondo Muni Airport             68  36  66  41  69 /   0   0   0   0   0
San Marcos Muni Airport        63  36  65  42  66 /   0   0   0   0   0
La Grange - Fayette Regional   63  36  64  42  65 /   0   0   0  -   -
San Antonio Intl Airport       65  38  65  44  67 /   0   0   0   0   0
Stinson Muni Airport           66  38  65  44  68 /   0   0   0   0   0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Mesoscale/Aviation...LH
Synoptic/Grids...Runyen
Public Service/Data Collection...YB



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