Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Austin/San Antonio Texas
1148 am CST Sat Dec 14 2019
18z aviation forecast below.
VFR conditions will prevail through the afternoon and night with
mostly clear skies. A shallow moisture return taking place early
Sunday morning may lead to the development of patchy fog 10z-15z
Sunday east of the taf sites, near and east of a pez-t20-gyb line.
In addition patchy stratus may develop and produce IFR/MVFR ceilings
east of I-35 and I-37 after 12z Sunday. Winds at 17z were light and
variable. A S to southeast wind around 7-10kt is forecast to develop
18z-20z. A few gusts around 15kt are possible during the afternoon.
Previous discussion... /issued 316 am CST Sat Dec 14 2019/
Short term (today through sunday)...
a nice weekend is in store for south central Texas with sunny skies
and temperatures well above normal for the middle of December. While
one trough surges towards the eastern Continental U.S. And the next approaches
California today the upper level pattern will be zonal across south
central Texas. Light and variable winds this morning will move around
to the south this afternoon marking the return of southerly flow.
Despite that, dry air across the Edwards Plateau could mean a few
isolated spots see elevated fire weather, but winds are forecast to
not be as gusty as they were yesterday. With the return flow in place
some patchy fog will be possible tonight into Sunday morning, mainly
along and east of the Interstate 35 corridor. During the day on
Sunday the next upper level trough moves across The Rockies on a path
towards the Southern Plains.
Long term (sunday night through friday)...
the tough will deepen as it approaches the Southern Plains Sunday
night into Monday. It will drag a cold front across the region to
begin the work week Monday morning with global models in decent
agreement that the front will arrive sometime around daybreak. With
only one real day of moisture return precipitation along the front
will be limited to areas east of Interstate 35. The best chance will
be during the first half of Monday as the front pushes east, with
drying and clearing conditions following by the late afternoon hours.
An isolated thunderstorm will be possible, but the majority of the
precipitation should remain showery in nature, with limited rainfall
totals. The big change with this front will be the cooler air behind
it as surface high pressure drops into Texas. Highs on Monday will be
be seasonal, but below normal temperatures will be in place for the
middle part of the week. Tuesday through Thursday will have highs in
the 50s and lower 60s, with freezing or near freezing temperatures
each morning. With clear skies and light winds it still looks like
most areas will see a light freeze going into Wednesday morning.
Return flow kicks in late Thursday into Friday ahead of the next
trough. While the 00z European model (ecmwf) and Canadian are now picking up the weak
Pacific front that the GFS has been carrying for several runs the
placement of the upper level trough and strength of the front are
still in question a week out. Because of this confidence remains
fairly low and so only slight chance pops have been maintained. If
models continue to trend into further agreement pops may need to be
bumped up slightly with subsequent forecasts.
Preliminary point temps/pops...
Austin Camp Mabry 52 80 56 62 37 / 0 0 - 20 0
Austin Bergstrom Intl Airport 50 82 57 64 35 / 0 0 - 20 0
New Braunfels Muni Airport 49 80 57 65 36 / 0 0 - 10 0
Burnet Muni Airport 51 81 49 58 32 / 0 0 0 - 0
del Rio Intl Airport 50 83 52 70 37 / 0 0 0 0 0
Georgetown Muni Airport 50 80 52 59 33 / 0 0 - 10 0
Hondo Muni Airport 48 83 53 72 35 / 0 0 0 - 0
San Marcos Muni Airport 49 81 57 65 35 / 0 0 - 20 0
La Grange - Fayette regional 55 83 63 68 37 / 0 0 20 40 0
San Antonio Intl Airport 51 80 57 67 38 / 0 0 0 10 0
Stinson Muni Airport 51 81 58 69 39 / 0 0 0 10 0