Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Austin/San Antonio Texas
556 am CST Friday Dec 19 2014
Aviation... /12z taf cycle/
IFR conditions prevail across south central Texas this morning as
of 12z as -shra/-dz and low ceilings combine to hamper visibilities in
the 2-5sm range. -Shra/dz for I-35 taf sites will continue through
16-18z timeframe with activity tapering off in the afternoon. Kdrt
currently MVFR (at 12z) but IFR ceilings lurk just north and will
likely infiltrate over site next hour. Slow MVFR improvement
expected through afternoon with VFR possible for kdrt. However, nam12
is more bullish than GFS on keeping clouds at kdrt and will
monitor if VFR will be possible. Expect return of IFR conditions
by Saturday morning with both ceiling and visible drops due to patchy
areas of fog 20/10-15z. Winds will out of the north at 10 knots or
less through rest of period.
Previous discussion... /issued 352 am CST Friday Dec 19 2014/
Short term (today through saturday)...
areas of rain...scattered showers and isolated thunderstorms
continued across south central Texas ahead of an upper level
trough moving east across western Texas with a surface trough
from deep south Texas northeast along the Texas coast. Synoptic
and isentropic lifting will maintain the precipitation. Some
locally heavy rains are expected early this morning across eastern
areas due to precipitable waters of 1.2 to 1.5 inches. The precipitation ends from
west to east later this morning into early afternoon as the upper
level trough axis moves across central Texas. Mostly cloudy skies
linger through Saturday most areas due to weak isentropic lift as
an upper level short-wave moves over Texas while the surface
trough persists across the Texas coastal waters. Below average
highs and above average lows are expected due to the cloud cover.
Long term (saturday night through thursday)...
an upper level trough sets up over the central states with a
series of short-waves moving across Texas Sunday through Tuesday.
A cold front will move across south central Texas Monday night
into early Tuesday. The moisture depth is too shallow for anything
other the maintenance of cloud cover. Below average temperatures
on Sunday...warm to above average on Monday due to southwesterly
lower level flow...then fall back to below average on Tuesday in
the wake of the front. Flow aloft becomes zonal on Wednesday with
a stronger southwesterly lower level flow creating a warming trend
with temperatures well above average on Christmas day. No rain is
expected with limited moisture. Another cold front is expected
just beyond this forecast early next Friday morning.
Preliminary point temps/pops...
Austin Camp Mabry 56 46 56 44 59 / 70 - - - 10
Austin Bergstrom international Airport 56 45 55 42 59 / 70 - - - 10
New Braunfels Muni Airport 58 45 58 44 61 / 60 - - - 10
Burnet Muni Airport 54 42 54 41 58 / 60 - - - 10
del Rio International Airport 64 46 60 46 62 / 10 - - - 10
Georgetown Muni Airport 54 43 54 42 57 / 70 - - - 10
Hondo Muni Airport 61 41 60 43 61 / 30 - - - 10
San Marcos Muni Airport 56 45 56 43 59 / 60 - - - 10
La Grange - Fayette regional 58 47 57 45 60 / 80 - - - 10
San Antonio International Airport 59 45 58 45 60 / 50 - - - 10
Stinson Muni Airport 60 46 60 46 61 / 50 - - - 10
public service/data collection...00