Area forecast discussion
National Weather Service Austin/San Antonio Texas
1144 PM CDT Thursday may 23 2013
Aviation...
MVFR stratus is beginning to develop across middle portions of the
region and will expand overnight. A complex of thunderstorms across
central Texas will slowly drift into the northern Hill Country
overnight. Current progression of the storms...and analysis of hi-
res models suggests a low potential for the storms to impact area
taf terminals overnight. Otherwise...anticipate ceiling bases to lower
to IFR at I-35 taf sites in the near-sunrise hours before lifting
during the middle/late morning hours and returning to VFR by 17-18z. Surface
winds will be southeast-southerly 5 to 10 kts overnight increasing to 10 to 15
kts Friday afternoon.
&&
Previous discussion... /issued 1041 PM CDT Thursday may 23 2013/
Update...
added isolated showers or thunderstorms along the northern edge
of The Hill Country and extending west to parts of the Edwards
Plateau to Val Verde County for tonight. The area of showers
and thunderstorms north of The Hill Country will develop to the
south and southwest the next few hours.
A series of short wave troughs from 500 to 300 hpa are forecast to move
just northwest of central and south central Texas through
Saturday...east of a 500 to 300 hpa larger scale trough over
the western u... lower heights to continue to develop
aloft over south central Texas. This will cause a slightly more
unstable environment for rain showers and thunderstorms and rain to develop. As a result
will maintain a slight chance of showers for the west to north
part of the area tonight. For Friday and Friday evening forecast
data available at hand this evening shows a slight chance of
showers along and west of ih35...as indicated by 00z may 24th
maps and input from the 18z...00z...and some of the European model (ecmwf) data
available. The weakness in the height field is forecast to
continue along the northwest part of south central Texas for
Saturday...therefore...showed a slight chance of showers
continuing near and west of ih35 on Saturday.
On Sunday and Monday the storm track is forecast to go slightly
north with more ridging forecast aloft over south central Texas.
As the storm track comes a little further south Tuesday through
Thursday...a slight chance of showers may develop again over the
west part of the area Wednesday and over all of south central
Texas by Thursday. Medium range forecasts differ on how long the
weakness in the height field will continue over the area late next
week...however most solutions beyond the first weekend of
June...June 1st and 2nd...suggest that ridging could increase
again over south central Texas from the southwest...if the storm
track does move north...as forecasts currently show.
Previous discussion... /issued 837 PM CDT Thursday may 23 2013/
Discussion...
continued trends with ongoing forecasts for the next few days.
A large scale 700 to 200 hpa trough over the western U.S. Is
forecast to continue through Saturday...drift slightly further
north by Sunday and Monday...and the move slightly further to the
south again by Tuesday through Thursday of next week. After
Thursday of next week...the storm track is forecast to eventually
with time carry this pattern north. A series of short wave troughs from
500 to 300 hpa are forecast to move just northwest of central
and south central Texas through Saturday...causing lower heights
to continue to develop aloft...and creating a slightly more
unstable environment for rain showers and thunderstorms and rain to develop. As a result
will maintain a slight chance of showers for the west part of the
area tonight. For Friday and Friday evening forecast data
available at hand early this evening shows a slight chance of
showers along and west of ih35...as indicated by 00z may 24th
maps and input from the 18z and some of the 00z forecast and European model (ecmwf)
data available. The weakness in the height field is forecast to
continue along the northwest part of south central Texas for
Saturday...therefore...showed a slight chance of showers
continuing near and west of ih35 on Saturday. For Sunday more
stable conditions slowly develop...as ridging aloft increases
again. As the storm track comes a little further south Tuesday
through Thursday...a slight chance of showers may develop again
over the west part of the area Wednesday and over all of
south central Texas by Thursday. Medium range forecasts differ on
how long the weakness in the height field will continue over the
area late next week...however most solutions beyond the first
weekend of June...June 1st and 2nd...suggest that ridging could
increase again over south central Texas from the southwest...if
the storm track does move north...as forecasts currently show.
Continued trends with ongoing forecasts through next week.
Previous discussion... /issued 637 PM CDT Thursday may 23 2013/
Aviation...
VFR conditions will prevail through this evening. MVFR ceilings will
redevelop by 05-06z along the I-35 corridor and spread west to
kdrt around 08-09z. Ceilings will improve to VFR by 17-18z. Southeast-southerly surface
winds of 10 to 15 kts this evening will decrease to 8 to 12 kts
overnight.
Previous discussion... /issued 302 PM CDT Thursday may 23 2013/
Short term (tonight through Friday night)...
convection will develop over the Mexican mountains this evening
and move toward the east. There is a slight chance for these
storms to move into Val Verde County. Forecast cape is around 2000
j/kg...so potential is for some storms to be severe. We have
issued a Severe Thunderstorm Watch for Val Verde County until 10
PM. The rest of the County Warning Area will be rain free as the upper level ridge
continues to build over the Southern Plains. The surface high
pressure is centered over the Gulf with southeasterly flow from
the Gulf. This will keep moist air in place. Skies will become
cloudy overnight. Friday an upper level short wave will move
through the ridge and there will be another slight chance for
thunderstorms over the western part of the region Friday and
Friday night.
Long term (saturday through thursday)...
Saturday the slight chance will spread to the east as far as
i10/i37. By Saturday night the upper short wave will move away
ending rain chances for the area. Then the entire County Warning Area will be in
the repeating pattern of overnight/morning clouds and clearing
afternoons. Temperatures will warm and be mostly above normal. The
next change will come Wednesday/Thursday of next week as an upper
level trough will move into West Texas and bring a chance for
thunderstorms to our County Warning Area.
&&
Preliminary point temps/pops...
Austin Camp Mabry 74 93 73 94 71 / 10 20 20 20 10
Austin Bergstrom international Airport 73 91 72 93 69 / 10 20 20 20 10
New Braunfels Muni Airport 73 92 71 93 70 / 10 20 20 20 10
Burnet Muni Airport 71 89 70 90 68 / 20 20 20 20 10
del Rio International Airport 77 90 74 92 73 / 20 30 30 20 10
Georgetown Muni Airport 72 89 71 91 69 / 20 20 20 20 10
Hondo Muni Airport 75 94 74 93 71 / 10 20 20 20 10
San Marcos Muni Airport 74 91 73 92 70 / 10 20 20 20 10
La Grange - Fayette regional 75 91 74 91 71 / 10 10 10 10 -
San Antonio International Airport 75 92 74 92 72 / 10 20 20 20 10
Stinson Muni Airport 75 92 74 92 71 / 10 20 20 20 10
&&
Ewx watches/warnings/advisories...
none.
&&
$$
Mesoscale/aviation...25
synoptic/grids...08
