Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Austin/San Antonio Texas
331 am CDT Sat Nov 1 2014
Short term (today through sunday)...
high pressure over The Big Bend region will cause dry northwest
winds for Saturday across the area. This will result in sunny
skies with highs below seasonal normals. As we fall back an hour
Sunday morning temperatures will drop into the low to middle 40s
across the I-35 corridor and Hill Country while the Rio Grande
plains see lows in the middle 50s. The surface high shifts east on
Sunday switching the winds around out of the southeast. Skies will
be partly to mostly cloudy Sunday with temperatures closer to
normal due to both Pacific moisture from Vance and the return of
moisture from the Gulf.
Long term (sunday night through friday)...
Monday will be a transition day as the high pressure continues to
push off to the east and the upper trough approaches from the west.
With the approaching trough and ample moisture in place areas
across The Hill Country and Edwards Plateau could see an isolated
showers or thunderstorm.
It is at this point where models begin to disagree concerning the
upper level trough. Of all of the Middle-Range forecast models the
GFS is the most progressive. It brings a cold front through the
area Tuesday into Wednesday with a deep trough across northern
Mexico becoming a cut off low across Texas Wednesday and Thursday.
GFS precipitable water values for Tuesday through Thursday range from 1.3 to 1.5
inches hinting at the possibility for some heavy rainfall.
The European model (ecmwf) is much slower with a trough over Arizona Tuesday into
Wednesday...a cut off low over northern Mexico Wednesday into
Thursday...finally ejecting out over North Texas Friday. The cold
front with the European model (ecmwf) is also slower by about 12 hours to move
through central Texas.
Another middle to long range model...the dgex seems to be a blend of
the European model (ecmwf) and GFS. It has the slower movement of the low while keep
the southern trajectory.
With so much disagreement in the models have gone with a
persistence forecast for now blending the models together...but
leaning heavier on the GFS. The best chances of rain at this point
look to be Tuesday and Wednesday...with lingering isolated
activity possible Thursday into Friday. With Pacific moisture from
Vance streaming in ahead of the trough there could be some locally
heavy rainfall. Depending on the track and timing of the trough there is
a chance that the moisture and lift from the trough are not timed
together...or we get dry slotted from the low...both decreasing
the chance and amount of rainfall. Despite this confidence remains
moderate to high that we will see a good chance for showers and
thunderstorms by the middle of next week due to the cold
front...the trough...and plentiful moisture.
The cold front will drop south central Texas temperatures to about
10 degrees below normal for the middle of next week with
temperature warming to near seasonal normals...in the low to middle
70s...by next weekend.
Preliminary point temps/pops...
Austin Camp Mabry 67 46 73 61 78 / 0 0 - 10 20
Austin Bergstrom international Airport 67 40 73 56 78 / 0 0 - 10 20
New Braunfels Muni Airport 70 46 75 60 80 / 0 0 - 10 20
Burnet Muni Airport 66 46 70 60 75 / 0 0 - 10 20
del Rio International Airport 72 56 74 64 80 / - - 10 10 20
Georgetown Muni Airport 66 43 71 59 76 / 0 0 - 10 20
Hondo Muni Airport 69 45 73 59 77 / - - 10 10 20
San Marcos Muni Airport 69 44 74 58 78 / 0 0 - 10 20
La Grange - Fayette regional 68 43 74 60 80 / - 10 10 10 10
San Antonio International Airport 71 51 75 64 80 / 0 0 - 10 20
Stinson Muni Airport 71 50 77 63 81 / 0 0 - 10 20