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

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FXUS64 KEWX 241135
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
535 AM CST Fri Nov 24 2017

.AVIATION...
VFR flying conditions are expected today through Saturday morning,
except patchy BR is possible east of I-35 early Saturday morning
where better moisture return is expected. There is a very small
possibility that this BR reaches some of the I-35 sites should flow
become more southeasterly, however, will leave mention out for now.
Southerly winds 7 to 12 KTs prevail with some higher gusts mid
morning into early evening, otherwise, winds less than 7 KTs are
expected today through Saturday morning.

&&

.PREV DISCUSSION... /ISSUED 359 AM CST Fri Nov 24 2017/

SHORT TERM (Today through Saturday)...
Another cooler than normal night with efficient radiational cooling
is occurring across South Central Texas as skies remain clear with
light and variable winds. Dew points are in the 30s across most of
the region and most areas aside from a few lower-lying areas with
drainage flows should stay above freezing this morning. Southwest
flow will return to the region today as weak high pressure along the
Texas-Louisiana border pushes east and another surface trough and
front pushes into the Texas and Oklahoma panhandles. Warm air
advection with 850 mb temperatures increasing from 10-13 deg C this
morning to 12-15 deg C by mid-afternoon combined with dry southwest
flow aloft will support high temperatures in the mid and upper 70s.
We may even see some lower 80s in the Rio Grande Plains if warm air
advection is a bit stronger and faster than anticipated.

Moisture advection ahead of a weak frontal passage expected tomorrow
afternoon and early evening may allow for advection fog to develop
in the Coastal Plains within a few hours of sunrise tomorrow. Skies
will be sunny once again with the front`s timing playing a large role
in how warm locations get. High temperatures should climb into the
lower 80s ahead mainly south of Interstate 10 and Highway 90 which
should stay ahead of the front until after peak daytime heating.
Elsewhere, highs should be similar to today in the mid to upper 70s.
Compressional warming ahead of and along the front should not be as
large tomorrow as it has with other recent frontal passages because
winds should back to the northeast without a pre-frontal trough for
most areas except our western counties. Once again, poor midlevel
dynamics and dry air aloft will keep this frontal passage dry.

LONG TERM (Saturday Night through Thursday)...
Sunday will only be a few degrees cooler than Saturday as the front
will quickly dissipate due to the relatively weak character of the
shortwave responsible for front and the building ridge to our west.
Southerly flow will quickly return by Monday as the ridge aloft moves
across Texas, allowing high temperatures to climb back into the mid
70s to lower 80s through Tuesday. Another shortwave disturbance will
move east off of the Rockies on Tuesday afternoon and evening to
attempt to push a weak front through the region on Wednesday morning.
Both the ECMWF and GFS show a negatively tilted trough lifting E-NE
into the Midwest on Wednesday. However, the GFS depicts a deeper low
that is displaced further southeast over Oklahoma that pushes a
front into the region while the ECMWF keeps it north of us. Our
forecast splits the difference between these two solutions, but there
may be a little more confidence in the ECMWF based on the lifting
trough and the operational GFS being cooler than its ensemble mean.
There is better model agreement that a stronger (but still dry) cold
front will move through the region on Thursday evening into Friday
morning as a shortwave digs into the lower Mississippi River Valley.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              77  50  76  50  74 /   0   0   0   0   0
Austin Bergstrom Intl Airport  77  45  77  51  75 /   0   0   0   0   0
New Braunfels Muni Airport     77  46  78  51  76 /   0   0   0   0   0
Burnet Muni Airport            77  47  74  48  71 /   0   0   0   0   0
Del Rio Intl Airport           77  46  78  50  73 /   0   0   0   0   0
Georgetown Muni Airport        77  48  75  50  72 /   0   0   0   0   0
Hondo Muni Airport             79  43  80  50  78 /   0   0   0   0   0
San Marcos Muni Airport        78  46  78  51  76 /   0   0   0   0   0
La Grange - Fayette Regional   75  48  79  52  75 /   0   0   0   0   0
San Antonio Intl Airport       77  48  79  51  77 /   0   0   0   0   0
Stinson Muni Airport           77  47  80  52  77 /   0   0   0   0   0

&&

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

$$

Mesoscale/Aviation...04
Synoptic/Grids...LH



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