Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Austin/San Antonio Texas
1255 PM CDT Thursday Jul 2 2015
a typical summertime pattern will continue throughout the taf
period. Expect VFR with patches of MVFR ceilings and southeasterly
winds at 10g25kt from 15z-06z...then MVFR becoming IFR ceilings from
06z-15z. There is a very small chance of isolated thunderstorms
this afternoon...but will leave it out of the tafs since even
storms getting into the vicinity is unlikely.
Previous discussion... /issued 1056 am CDT Thursday Jul 2 2015/
Update... /update for fog removal/
current forecast is on track with more stability noted on cumulus
from satellite visible imagery. A weak sea-breeze feature appears to
be forming near Goliad...so will expand isolated probability of precipitation into
eastward into a few counties of the coastal prairies. Any changes
to temperatures and relative humidity were mainly cosmetic adjustments from populating
Previous discussion... /issued 640 am CDT Thursday Jul 2 2015/
Aviation.../12z taf cycle/
Low IFR to MVFR stratus as developed as expected but so far as only
impacted kaus through the morning hours while on the fringe of
ksat/kssf. Latest satellite imagery shows decreasing stratus
coverage and it may move out of kaus next couple of hours.
Furthermore...stratus deck may not directly impact ksat/kssf through
14z before it mixes out completely. There are some areas of patchy
fog with visibility ranging from 1/2sm locally at kbaz to 3-6 sm
for points along the I-35 corridor and near La Grange. Visible will
improve through the middle morning hours with VFR prevailing.
Less rain showers activity is expected today with only isolated activity
that may not directly impact any taf site. Have opted to not
include any weather wording. Ksat/kssf would have the greatest
potential out of all the sites for this isolated activity during
the afternoon. South surface winds will be near 5-10 knots this
morning...increasing to 15 knots with some gusts to 20 knots this afternoon
before falling below 10 knots again tonight. MVFR and IFR will return
more quickly by 06-08z to central taf sites with LIFR possible as
well going into Friday morning.
Previous discussion... /issued 612 am CDT Thursday Jul 2 2015/
patchy fog is beginning to develop across the southeast. Have
added patchy fog for most of the rest of this morning.
Previous discussion... /issued 331 am CDT Thursday Jul 2 2015/
Short term (today through friday)...
upper air analysis last evening showed a high centered over Utah
extending to the southeast over Texas and an inverted trough
pushing up from Mexico into south Texas. A large amplitude trough
covered the eastern half of the country. At the surface...high
pressure was centered over the Gulf and winds were from the
southeast. Dew point temperatures were down a few degrees from 24
hours ago. The short term will see a battle between the upper
ridge over the west and the trough to the east. The trough will
attempt to erode the ridge over Texas. Models show good agreement
that the ridge will win out through Friday. This will mean a
mainly dry forecast...the wildcard in this scenario is the
inverted trough to the south. This feature will allow convection
to form over the south today...so have some slight chance probability of precipitation
down there. Temperatures will be a little warmer than Wednesday.
Long term (friday night through wednesday)...
the upper level trough looks like it will push back the ridge to
the northwest for the weekend. This will bring increasing rain
chances Saturday and Sunday particularly over the eastern half of
the County Warning Area. GFS and European model (ecmwf) are showing differences for the weekend
with the GFS drier. Will go with a compromise at this point as
drier is the new trend...so will hold on to some probability of precipitation for now.
Monday the upper ridge will build solidly over Texas and begin a
dry forecast that will continue through the end of the period.
Preliminary point temps/pops...
Austin Camp Mabry 74 91 74 90 76 / - 10 - 30 -
Austin Bergstrom international Airport 74 91 74 91 76 / - 10 - 30 10
New Braunfels Muni Airport 73 91 74 90 75 / - 10 - 30 10
Burnet Muni Airport 73 90 73 90 75 / - 10 - 20 -
del Rio International Airport 74 93 75 94 75 / - 10 0 10 -
Georgetown Muni Airport 74 91 74 90 75 / - 10 - 20 -
Hondo Muni Airport 73 91 74 91 74 / 10 - - 20 10
San Marcos Muni Airport 74 91 74 90 76 / - 10 - 30 10
La Grange - Fayette regional 75 92 75 90 77 / - 10 - 30 10
San Antonio International Airport 74 91 75 90 76 / 10 - - 20 10
Stinson Muni Airport 74 91 75 91 76 / 10 10 - 20 10
public service/data collection...LH