Scientific Forecaster Discussion
fxus64 kewx 200948
Area forecast discussion
National Weather Service Austin/San Antonio Texas
348 am CST Fri Jan 20 2017
Short term (today through saturday)...
fine tuning the fog forecast for this morning has been the focus for
the short term period as areas of dense fog have developed over the
majority of the County Warning Area east of the I-35 corridor. The fog bank has
enveloped the I-35 corridor from Bexar to southern Travis County and
an analysis of the hrrr has shown this for consistent runs. As of
330am, this bank has largely slowed its westward progression which
will be enough to impact the entire Interstate corridor to about the
Austin Metro area. However, as a steep moisture gradient exists to
the west, much of the Comal, Hays, and Travis counties will see
little to any fog while the eastern quarter or less will see
otherwise areas of dense fog. Thus, the decision was made to include
these areas in a dense fog advisory through 15z through collaboration
Otherwise, another well above average temperature day will be in
store as highs in the mid to upper 70s are forecast. Should stay 7-8
degrees below any high temperature records however.
A weak disturbance over the southeast Texas coast may bring some shower and
isolated thunderstorm activity to the coastal plains but chances look
rather low according to the ttuwrf and hrrr.
Long term (saturday night through thursday)...
the main long term period concern will be the continued wind
potential for mostly Sunday but also possibly as early as Saturday
evening in the western zones. A deep 500 mb closed low will develop off
the Lee of the southern rockies and push across the Red River valley
while generating a sub-995 mb surface low that will traverse the same
path. This will create a 20+ mb gradient from the Red River to the
Rio Grande by Sunday morning and the gradient shifting winds to the
northwest as the sfc low continues to push east into the MS River
Valley. As it stands this morning...guidance varies anywhere from
18-30 kts of sustained winds mid day Sunday as both the pressure
gradient is maximized and daytime vertical mixing effects combine.
Thus...breezy to windy conditions look to begin out west as early as
Saturday evening, persist through the overnight hours, and increase
throughout Sunday morning spreading east encompassing the entire
County Warning Area...peaking mid day Sunday and finally subsiding around 00z
Monday. Therefore, the a Wind Advisory continues to look well
warranted Sunday. Additionally, low relative humidity values during this windy
period along the Rio Grande River will increase the fire weather
threat, but will address this in more detail in the fwfewx.
Otherwise, a mostly dry extended period looks likely in the models
for next week. A cold front passage Tuesday night should cool
temperatures to more normal January temperatures for the latter half
of the week.
Preliminary point temps/pops...
Austin Camp Mabry 77 52 76 50 68 / 10 - 20 10 0
Austin Bergstrom Intl Airport 76 51 76 49 69 / 10 - 10 10 0
New Braunfels Muni Airport 76 52 76 49 69 / 10 - 10 10 0
Burnet Muni Airport 74 47 73 47 64 / 10 0 20 20 0
del Rio Intl Airport 76 48 78 50 70 / 10 0 10 0 0
Georgetown Muni Airport 75 49 75 49 66 / 10 - 20 20 0
Hondo Muni Airport 78 49 79 47 71 / 10 0 - - 0
San Marcos Muni Airport 76 52 76 49 69 / 10 - 10 10 0
La Grange - Fayette regional 76 56 74 51 68 / 10 20 10 10 0
San Antonio Intl Airport 77 53 77 51 70 / 10 0 - 10 0
Stinson Muni Airport 77 53 78 51 71 / 10 - - - 0
dense fog advisory until 9 am CST this morning for the following
counties: Atascosa...Bastrop...Bexar...Caldwell...De Witt...