Scientific Forecaster Discussion
fxus64 kewx 202334
Area forecast discussion
National Weather Service Austin/San Antonio Texas
634 PM CDT Fri Apr 20 2018
00z aviation forecast below.
currently MVFR ceilings ongoing along and west of a kt82-ksat line.
MVFR ceilings will gradually expand northeast through the mid and
late evening hours. Eventually ceilings across much of the region
will lower into IFR range overnight and through the morning hours
with patchy -ra and scattered -shra developing. The IFR ceilings are
expected to develop at Sat/ssf roughly between 06z-09z, at aus and
drt between 09z-12z. A dry line will move through western areas early
afternoon with improving conditions to VFR ceilings at drt. Ceilings
are forecast to improve to MVFR at Sat/ssf/aus in the afternoon with
shras and possible tsras focusing east of the taf sites mid to late
afternoon. Winds east to southeast 10-15 kts this evening decreasing slightly
overnight and in the morning. Some occasional gusts near 25 kts at
drt through the evening hours.
Previous discussion... /issued 249 PM CDT Fri Apr 20 2018/
Short term (tonight through Saturday night)...
a cloudy day continues for most of south-central Texas with cool
conditions and winds out of the east. Temperatures are currently in
the 60s for much of the area which is well below normal for this time
of the year. Still continuing to see some light radar returns across
the southern half of the County Warning Area this afternoon, but these are being
measured around 15 kft and drier air below that is likely evaporating
much if not all of the precip before it reaches the ground. Think
most of the evening and early portion of the tonight forecast will
remain dry outside of some possible sprinkles.
A large upper level low will continue to push east into the Central
Plains which will bring most of the deep forcing for ascent well
north of our area. High-res models show some possible shower activity
underneath a weak capping inversion for late tonight and into
tomorrow morning. By the late morning hours a dryline will be moving
through our western counties and we could see a bit higher coverage
of scattered showers and thunderstorms in the afternoon hours. By
mid-day the dryline is expected to be just west of the Highway 281
corridor and the best chances for thunderstorms will be east of this
area. Forecast soundings show about 750-1000 k/kg of cape with ample
shear and with these parameters could not rule out a strong to
marginally severe storm, especially in our northern counties in
the closest proximity to the upper low. The activity is expected to
shift east in the evening hours and there remains the possibility of
a broken line of showers and thunderstorms along the associated cold
front Saturday night. Highs tomorrow will top out in the middle 70s
east of the dryline and up into the middle 80s west of the dryline.
Long term (sunday through friday)...
Sunday will be quite nice across the area with mostly clear to partly
cloudy skies with highs in the 70s to lower 80s. Northerly flow will
continue into Monday keeping temperatures persistent for the start of
the work week. A progressive pattern is shaping up with the GFS and
European model (ecmwf) both showing a cold front arriving for Wednesday. The European model (ecmwf)
is much wetter than the GFS, but with the way these things have been
going with higher pops in the extended and lowering as we get
time progresses, will cap pops at 20 percent. Another front is
possible on Friday and this should be a dry front. With the passages
of a few fronts over the next 7 days, temperatures will remain in the
70s and 80s with lows primarily in the 50s. This should be at or just
below normal for this time of year.
Preliminary point temps/pops...
Austin Camp Mabry 59 76 55 76 54 / 30 50 30 0 0
Austin Bergstrom Intl Airport 58 75 55 76 52 / 30 50 30 0 0
New Braunfels Muni Airport 60 76 56 78 53 / 20 40 20 0 0
Burnet Muni Airport 57 75 51 74 51 / 30 40 20 0 0
del Rio Intl Airport 64 87 57 84 59 / 20 10 0 - -
Georgetown Muni Airport 57 74 52 74 51 / 30 50 30 0 0
Hondo Muni Airport 63 81 57 82 54 / 30 30 10 0 -
San Marcos Muni Airport 59 76 56 77 52 / 30 50 30 0 0
La Grange - Fayette regional 59 76 59 76 53 / 20 60 40 - 0
San Antonio Intl Airport 62 77 58 79 56 / 20 40 20 0 0
Stinson Muni Airport 63 78 59 80 56 / 20 40 20 0 0