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Area forecast discussion 
National Weather Service Austin/San Antonio Texas
1223 am CDT Sat Aug 1 2015

Aviation... /06z taf update/
VFR skies are forecast at taf sites through the next 24-30 hours.
Weak divergence pattern in surface winds should lead to little
or no overnight stratus below 3000 feet. Middle level clouds from
convective debris over The Hill Country into the drt area should
yeild ceilings mainly above 5000 feet above ground level and perhaps an isolated
sprinkle through daybreak. A few areas could develop light
fog...but lack of rainfall east of I-35 and a general low level
drying from the east should limit fog potential at I-35 taf sites.
In later periods...a few storms could impact drt in the afternoon
with shifty outflow winds that should diminish in the early
evening.

&&

Previous discussion... /issued 918 PM CDT Friday Jul 31 2015/

Update...
due to heating in place...temperatures in the lower 90s as of 9
PM...isolated storms are ongoing across part of The Hill Country.
These storms are producing moderate to heavy rain with a good
amount of cloud to ground lightning strikes and wind gusts up to
30 miles per hour. This activity is expected to diminish within the next hour
or two. Rest of tonight into Saturday should be rain-free as drier
air pushes from the northeast and spreads over most of south
central Texas.

Previous discussion... /issued 655 PM CDT Friday Jul 31 2015/

Aviation...
PM convection is shifting south and west...but earlier did
produce some decent outflow. All this PM convection will dwindle
as the sun GOES down with a lot of left over boundaries. Tafs
should be fairly quiet this cycle as moisture that gave a
scattering of convection today will push farther west by
tomorrow. As a result have not included mention of sh/ts in
aus/Sat/ssf...but did input a thunderstorms in the vicinity for drt Saturday afternoon. Relative humidity
plots show that middle level moisture will stick around and with
mainly east and NE flow from the surface up to 300 mb...not expecting
much in the way of low cloud development. Light north/NE winds
tonight...becoming a bit more east on Saturday. I dont think there
was enough rain at any of the sites to promote any widespread fog
tonight but might see some patchy ground fog with areas that have
damp ground.

Previous discussion... /issued 634 PM CDT Friday Jul 31 2015/

Update...
heat advisory expired at 6 PM this afternoon. However...heat
indices will remain around 100 to 108 across the southern counties
through 7 PM this evening. Scattered showers and isolated storms
pushing away from the San Antonio metropolitan area but heading toward
the southern part of the Rio Grande plains.

Scattered showers and isolated thunderstorms are heading to the
southwest late this afternoon into early evening. Some of these
storms and outflow boundaries are capable of producing wind gusts
of 40 to 50 miles per hour with brief but heavy rain. These thunderstorms are
also producing a good amount of cloud to ground lighting strikes.
These storms will continue to push on a southwest general
direction about 20 to 25 miles per hour. Hires models are suggesting for this
activity to diminish within the next few hours as we lose daytime
heating and drier air filters in from the northeast.

Previous discussion... /issued 250 PM CDT Friday Jul 31 2015/

Short term (tonight through Saturday night)...
heat index values are around advisory levels across our counties
near the coastal plains. They will continue at those levels for
the remainder of this afternoon. Have issued a heat advisory for
Delaware Witt...Fayette...Gonzales...Karnes and Lavaca counties through
6 PM.

Isolated to widely scattered showers and isolated thunderstorms
have developed across south central Texas as daytime heating has
interacted with an area of deeper moisture with precipitable waters of 1.5 to 2
inches that rotated to the southwest under the subtropical ridge
centered over the southern rockies. These will continue through
this afternoon and slowly dissipate this evening with loss of
daytime heating.

The deeper moisture will continue drifting west and lay across the
Edwards Plateau to Rio Grande plains as drier air with precipitable waters of 1.2
to 1.6 inches currently over the Mississippi Valley moves to the
I-35 corridor on Saturday. Expect isolated to widely scattered
showers and thunderstorms to develop mainly west of I-35 Saturday
afternoon with the greatest coverage over Edwards and Val Verde
counties. The rains will end by evening with loss of daytime
heating and as drier air continues to spread to the west.

Long term (sunday through friday)...
the subtropical ridge remains centered over the southern rockies
and Southern Plains. Below normal moisture levels with precipitable waters of 1 to
1.5 inches continue as well over south central Texas. Have removed
probability of precipitation for Sunday where previously mentioned in the northern Hill
Country and southern Edwards Plateau as dry air takes over. No
rain is expected due to strong subsidence and below normal
moisture levels. San Antonio international will reach 100 for
the first time this year during the next few days while the other
climate sites add to their totals.

&&

Preliminary point temps/pops...
Austin Camp Mabry 77 101 76 101 76 / - - 0 0 0
Austin Bergstrom international Airport 72 100 74 100 74 / - - 0 0 0
New Braunfels Muni Airport 73 101 75 101 75 / - - 0 0 0
Burnet Muni Airport 74 99 75 99 75 / - - 0 0 0
del Rio International Airport 77 101 78 101 78 / 10 - 0 0 0
Georgetown Muni Airport 74 99 76 99 76 / - - 0 0 0
Hondo Muni Airport 73 100 74 100 75 / - - 0 0 0
San Marcos Muni Airport 73 101 75 100 75 / - - 0 0 0
La Grange - Fayette regional 74 100 76 99 76 / - - 0 - 0
San Antonio International Airport 77 100 76 100 77 / - - 0 0 0
Stinson Muni Airport 75 101 76 101 76 / - - 0 0 0

&&

Ewx watches/warnings/advisories...
none.
&&

$$

Mesoscale/aviation...Oaks
synoptic/grids...Hampshire

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