Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Austin/San Antonio Texas
650 PM CDT Sat Apr 25 2015
VFR conditions will prevail across area sites through late this
evening. Dewpoint temperatures in the upper 60s and lower 70s
will push northward from the coastal plains into the I-35
corridor. This will result in lowering ceilings/visibilities into the
MVFR/IFR category. Patchy fog is expected along and east of the
I-35 corridor overnight into middle Sunday morning as surface airmass
stays saturated. Low clouds are forecast to lift by 16z-18z time
frame for VFR conditions. Across kdrt...MVFR ceilings can not be rule
out by 12z Sunday for couple of hours...but overall VFR for most
of the period. Winds will be from the southeast and south at 5
knots or less. Winds are expected shift to the southwest across
the Rio Grande plains Sunday as the dry-line pushes to the east.
Wind gusts up to 20 knots are anticipated along the dry-line.
Previous discussion... /issued 329 PM CDT Sat Apr 25 2015/
Short term (tonight through Sunday night)...
late afternoon surface observations show the leading edge of the
dryline has for the most part moved east of I-35. Much drier air
continues to filter in behind the dryline with dew points in the
upper 30s at Rocksprings...compared with middle 60s at La Grange.
The vast majority of south central Texas will remain precipitation
free this afternoon and early evening. Some weak convergence along
the dryline across DeWitt and Lavaca counties could provide enough
focus for isolated showers and storms during peak heating hours
today. Otherwise...the dryline will retreat westward overnight and
Gulf moisture will quickly move back into south central Texas.
Given recent rains along with good moisture advection...we have
added fog to the forecast for areas generally along and east of
the I-35 corridor. On Sunday...the dryline will mix eastward and
sharpen during the late morning and afternoon hours. Daytime
heating and convergence along the dryline should be enough to
generate mainly scattered convection during for areas generally
east of Highway 83. The Storm Prediction Center day 2 outlook continues to show a
slight risk for severe storms along and north of a Bandera to
Bastrop line and we have mentioned this in the latest hazardous
The dryline will briefly retreat westward Sunday evening...but
will then be overtaken by a Pacific cold front moving in from the
west. The latest round of model guidance suggests additional
convection will develop during the late evening and overnight
hours across the southern Edwards Plateau and Rio Grande plains.
Some severe storms are possible during the afternoon through
overnight hours...with large hail and damaging winds being the
Long term (monday through saturday)...
the forecast for Monday will likely remain active as an advancing
Pacific cold front along with an upper low dropping slightly
southward will lead to good rain chances along and mainly east of
I-35. Strong to severe thunderstorm development is again a
possibility for areas along and east of a Burnet to Karnes City
line. Large hail and damaging winds will again be the main
concern. The Pacific cold front finally advances south of the
region on Tuesday and other than the possibility of morning
showers and storms north of Highway 71...a drying trend is
expected. The upper low moves east into the lower MS River Valley
on Wednesday...with a trailing upper trough axis likely to linger
through late in the work week. Despite the presence of the upper
trough...we expect dry weather given a continued dry...northwest
flow in the lower levels. Temperatures will remain at or below
normal for Tuesday through Saturday.
Preliminary point temps/pops...
Austin Camp Mabry 66 87 67 84 60 / - 30 30 40 20
Austin Bergstrom international Airport 63 85 66 83 59 / - 30 30 40 20
New Braunfels Muni Airport 64 86 67 84 61 / - 30 30 40 10
Burnet Muni Airport 62 86 62 83 57 / - 40 40 30 30
del Rio International Airport 65 90 62 88 61 / - - 20 10 -
Georgetown Muni Airport 63 85 65 83 58 / - 30 40 40 30
Hondo Muni Airport 64 88 65 86 60 / - 20 30 30 -
San Marcos Muni Airport 65 85 67 83 60 / - 30 30 40 20
La Grange - Fayette regional 70 86 70 82 63 / - 30 30 60 30
San Antonio International Airport 66 88 68 86 62 / - 30 30 30 10
Stinson Muni Airport 66 87 69 85 62 / - 30 30 40 10
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