National Weather Service Raw Text Product

Displaying AFOS PIL: AFDEWX Received: 2019-01-12 11:27 UTC

FXUS64 KEWX 121127

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
527 AM CST Sat Jan 12 2019

Conditions to continue to improve across South-Central Texas as
drier air filters into the area. Winds will shift later this morning 
to the northwest and speeds this afternoon will be near 15 knots. 
Speeds will lessen once again after sunset with VFR conditions 
continuing tonight. 


.PREV DISCUSSION... /ISSUED 338 AM CST Sat Jan 12 2019/ 

SHORT TERM (Today through Sunday)...
The morning fog pattern is shifting east and shrinking slightly in
area due to the winds in the boundary layer turning more W/NW over
the higher terrain of the northern Hill Country and southern Edwards
Plateau. These elevated winds will take a while longer to descend
into the lower elevations and latitudes while the cyclonic flow aloft
acts to maintain a strong low level inversion at the surface. The
subsident flow will mix east on the lee side of the upper low and
mix out the fog closer to daybreak across counties along and east of
the I-35 corridor. A couple far SE counties were in the presence of
multiple cloud layers and were left out of the updated dense fog
advisory area, but a brief lowering to 1/4 mile is possible before 
winds perk up after 12Z. Will continue to run the advisory through 
12Z and update to extend or cancel an hour either side if necessary. 
By 13z, dense fog areas are expected and the surface winds are shown 
in the rapid refresh models to be turned to westerly across the area 
while higher terrain areas over our nw CWA trend to the northwest. 
This will be the arrival of the polar front, but the frontal passage 
will be too subtle to specify timing for a given location as winds 
shift in direction and increase gradually. 

Surface pressure rises early today should be somewhat steady, but 
afternoon mixing should accelerate the cool air advection pattern 
with the northern counties seeing the most impacts on high temps. 
Southern counties should see max temps reaching above mid-January 
normals, but temperatures will react more rapidly by this evening. A
light freeze is forecast for parts of the Hill Country Sunday
morning. The cool air advection and dry air will continue through the
rest of the short-term, with Sunday afternoon temperatures about 3-5
degrees below mid-January normals. 

LONG TERM (Sunday Night through Friday)...
Sunday night/Monday morning might have been the coolest morning
behind todays polar front, but a zonal pattern aloft is suggesting
some mid level clouds skirting across South TX late Sunday into
Monday. Timing of these clouds could allow for pockets of clearing
and a few areas could drop to the freezing mark again given the dry
low level air in place. Light northerly cold air advection continues
into Monday, with more model support for mid-level overrunning of
moisture and clouds for Tuesday. The diurnal range shrinks, but
should hold highs to near or below daytime normals through Tuesday.
Included in this overrunning pattern is a slight chance to low chance
PoPs for showers, and the blended guidances are trending wetter as 
the influences from the better resolution NAM model takes effect. 
Rain from this weak overrunning pattern should remain light with the 
best lift rooted over the TX Coastal Bend. Intermittent light rain or
sprinkles could continue each day in advance of a Polar trough to 
impact the area Friday, but the model consensus shows the most 
pronounced lift from the overrunning pattern Tuesday. The Friday 
trough will pass mainly north of South TX leaving an uncertain 
picture of rain potential, but trends over the past couple days 
suggest a deeper polar trough that may be shifting further south with
each future model run. This could signal a better chance for deep 
convection Friday and a more extended chance of rain into early 

In addition, during the passage of the next Polar system, the 
pattern over Eastern Canada is sharpening meridional flow to signal 
a more Canadian style front for next weekend. The ECM and CMC show 
the colder scenarios for next Saturday, but the GFS has actually 
trended toward a weaker connection to the Arctic pattern over the 
past day. Will favor a guidance blend for now and expect future 
guidances to trend slightly colder while the solutions remain mixed.


Austin Camp Mabry              61  37  52  37  53 /   0   0   0  -    0 
Austin Bergstrom Intl Airport  62  36  52  36  53 /   0   0   0  -    0 
New Braunfels Muni Airport     65  37  53  38  53 /   0   0   0   0   0 
Burnet Muni Airport            58  34  52  35  52 /   0   0   0  -    0 
Del Rio Intl Airport           68  40  56  40  55 /   0   0   0   0   0 
Georgetown Muni Airport        59  35  52  36  52 /   0   0   0  -    0 
Hondo Muni Airport             69  37  56  39  55 /   0   0   0   0   0 
San Marcos Muni Airport        64  37  53  38  52 /   0   0   0   0   0 
La Grange - Fayette Regional   65  37  53  38  54 /  -    0   0  -   -  
San Antonio Intl Airport       67  38  54  39  54 /   0   0   0   0   0 
Stinson Muni Airport           69  39  56  40  54 /   0   0   0   0   0