Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Austin/San Antonio Texas
546 am CST Friday Feb 12 2016
VFR conditions were being reported across all the taf sites this
morning. With higher dewpoints and increasing low level moisture
could see a brief period of some MVFR visibilities at kaus. Have
included a tempo group to account for this between 13z and 15z.
Current thinking is that fog will remain out of the other I-35
terminals. After 15z VFR conditions will prevail through early
Saturday morning when we expect to see MVFR ceilings develop between
09z-11z at the I-35 sites. Winds will become east/NE at 5-10 knots
after 16z then more northerly overnight and into Saturday
morning. Could once again see some fog especially at kaus around
Previous discussion... /issued 417 am CST Friday Feb 12 2016/
Short term (today through saturday)...
Overview...despite a weak cold front passage this afternoon -
near to above normal temperatures will remain in place. More
clouds and cooler conditions are expected Saturday with continued
Synoptic 500 mb pattern over the Continental U.S. This morning per water vapor and
rap analysis reveals a longwave trough over eastern Continental U.S. Arcing northwest
back into the north Central Plains. A 500 mb ridge is in place across
the Desert Southwest and this is placing Texas in weak northwest 500 mb flow
with noted shaper shortwave over the middle MS valley. This feature
alongside a strong Canadian surface high pressure system will send a
weak front into the region this afternoon. H925 temperatures ranged 24-18c
west to east yesterday that allowed for near record heat. Values
will range around 23-15c today so maximum highs are not expected to
reach yesterdays values. Still - above normal and quite pleasant
conditions are expected as humidity remains low.
For Saturday...expect more clouds in the morning across a good
portion of the region that will slowly erode through the afternoon.
Clouds will dissipate quickest in the SW and central areas. Based on
some implied weak isentropic lift over-top of the weak front that
stalls over the region...low-lvl moisture may become trapped under
an inversion and be tougher to clear out in NE areas through the
afternoon. Due to this and the cooler h925 temperatures...surface
temperatures may not reach 70f towards the Austin area while San
Antonio and points SW will warm up more.
Long term (sunday through next thursday)...
Other than some light drizzle and low-end light rain chances for
portions of Sunday and early Monday for eastern locations...a dry
week is expected. Temperatures will recover into next week and
remain above normal in the middle 70s to low 80s.
More clouds are expected to develop late Saturday into Sunday
morning and this low-level saturation could lead to patchy areas
of light rain and drizzle. Little to no accumulation is expected
and dry conditions will continue through the next week.
The western Continental U.S. Ridge will break down slightly Sunday into Monday due
to a stronger 500 mb shortwave digging south across the Central Plains.
Most models have trended farther north with the better lift and
dynamics associated with this piece of energy with minimal rain
chances for this region. If the track of this system shifts south
then additional rain chances will need to be added to NE
locations. For now have gone with low-end /20%/ light rain chances
for far eastern locations but best precipitation location will be
towards east/North Texas. There could be some possibility of
thunderstorms just North/East of our area towards Waco and Houston
Monday morning given 100-300 j/kg MUCAPE. However - feel risk is
to low to include for our region given ingredient disconnect here.
A stronger front moves through Monday afternoon but no true cold
air resides behind it.
For Tuesday-Thursday - expect sunny skies with above normal temperatures
and continued worsening fire weather conditions. While no red flag
criteria is expected to be met at this point...fuels will
continue to dry out and the energy release component values will
likely continue to climb.
Preliminary point temps/pops...
Austin Camp Mabry 78 47 66 53 73 / 0 0 0 10 20
Austin Bergstrom international Airport 77 43 66 51 73 / 0 0 0 10 20
New Braunfels Muni Airport 79 46 70 52 75 / 0 0 0 10 10
Burnet Muni Airport 75 43 65 51 71 / 0 0 0 10 10
del Rio International Airport 84 49 76 54 78 / 0 0 0 - -
Georgetown Muni Airport 75 43 64 50 72 / 0 0 0 10 10
Hondo Muni Airport 82 45 73 52 77 / 0 0 0 - -
San Marcos Muni Airport 77 45 67 51 73 / 0 0 0 10 20
La Grange - Fayette regional 77 49 66 51 73 / 0 0 - 10 20
San Antonio International Airport 80 47 70 54 75 / 0 0 0 10 10
Stinson Muni Airport 80 47 72 54 77 / 0 0 0 - 10
dense fog advisory until 9 am CST this morning for the following
counties: Delaware Witt...Fayette...Gonzales...Karnes...Lavaca...Wilson.