Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Austin/San Antonio Texas
539 PM CST Monday Nov 30 2015
Aviation... /00z tafs/
A weak front is slipping across The Hill Country and should result
in light northerly winds developing this evening over the I-35 taf
sites while making less of an impact at drt. The bigger impact of
this front is to lessen the potential for low clouds or fog to
form in an area of relatively high low level moisture. Some patchy
light fog and IFR/MVFR ceilings...some still hanging around
aus...should shift southeast into the coastal prairies later in
the evening as models show slightly higher boundary layer winds to
bring in drier air. Late taf periods after 06z show minimal
impacts from clouds or winds...except for some borderline IFR/MVFR
conditions at drt from 13z to 17z.
Previous discussion... /issued 252 PM CST Monday Nov 30 2015/
Short term (tonight through Tuesday night)...
No major highlights through Tuesday as continued below normal
temperatures and low end light rain/drizzle chances are in place
for the coastal plains.
Areas of The Hill Country and the southern Edwards Plateau are
seeing some peeks of sun this afternoon as the low-level cloud cover
slowly abates due to a weak front sliding into the region. Clouds
have remained over the I-35 corridor and areas southeast where
light drizzle has been reported towards Gonzales and La Grange.
The low-level clouds should continue to break up over the next 6-12
hours for the I-35 corridor per NAM/GFS bufr soundings suggesting
drier air mixing down as well advecting in from the west. The
coastal plains will likely see some of this drier air mix in as
well that could temporarily end the light drizzle through portions
of the overnight. The 20-30% of drizzle will return Tuesday but
most activity will be confined to the coast through the afternoon.
Temperatures will be slightly warmer tomorrow given less low-level
clouds but the middle and high clouds will keep temperatures from
reaching their full potential.
Long term (wednesday through monday)...
No hazards within the long term period as a cold front with some
showers is expected to move through early Wednesday morning with
clearing and sunny conditions expected through the end of the
A large anticyclonic gyre currently resides over the Central
Plains and this feature plus an attendant trough that develops on
the backside across The Four Corners late Tuesday into Wednesday
will drive a front through the region. Given a weak semi-
persistent surface high over North Texas and lower surface
pressure over Mexico, the surface winds will have a tough time
becoming more easterly or southeasterly ahead of the front. Due to
this wind direction through 700mb, the moisture return will be
lacking as precipitable waters only recover to 1.0" to 1.3" from the I-35
corridor southeast towards the coastal plains before the front
moves through Wednesday morning. Due to this factor and overall
weak forcing...widespread shower activity is not expected with the
passage of the front with most action confined to the coastal
plains at a 30-40% level right now. Wednesday morning lows will be
a bit tricky as the ensemble guidance has a large range given
frontal timing and degree of drier air advecting in from the
north. Sided more with a colder solution with the GFS ensemble
mean opposed to the warmer guidance offered with the superblend.
Clearing conditions are expected through the day Wednesday
afternoon and continue through Saturday with temperatures becoming
more normal towards the end of the week. A stronger shortwave
trough will take form over the weekend and bring in more clouds by
Sunday with only low end shower chances being possible for Monday
as moisutre continues to remain limited.
Preliminary point temps/pops...
Austin Camp Mabry 45 61 42 62 40 / 10 10 20 10 -
Austin Bergstrom international Airport 43 61 42 62 38 / 10 10 20 10 -
New Braunfels Muni Airport 46 61 43 63 38 / 10 10 20 10 -
Burnet Muni Airport 42 60 39 60 36 / 10 10 10 - -
del Rio International Airport 48 64 47 65 41 / - - 10 - -
Georgetown Muni Airport 41 59 41 60 36 / 10 10 20 - -
Hondo Muni Airport 45 62 44 63 36 / 10 10 20 10 -
San Marcos Muni Airport 45 60 41 62 38 / 10 10 20 10 -
La Grange - Fayette regional 49 61 45 62 40 / 20 20 30 10 -
San Antonio International Airport 48 62 44 62 39 / 10 10 20 10 -
Stinson Muni Airport 49 62 45 62 40 / 10 10 20 10 -
public service/data collection...LH