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Area forecast discussion...updated 
National Weather Service Austin/San Antonio Texas
703 PM CDT sun Apr 19 2015

Update...
please see the 00z aviation discussion below.

&&

Aviation...
VFR conditions are expected at area taf sites through the current
forecast period. A cold front will continue to sag southward
through the region for the remainder of this evening into the
overnight hours. Convection along the front will continue east of
I-35...so we will not mention any thunderstorms and rain for our I-35 taf sites.
Otherwise...winds will transition to a more northerly direction
overnight...then more east to southeast by late tomorrow
afternoon.

&&

Previous discussion... /issued 256 PM CDT sun Apr 19 2015/

Short term (tonight through Monday night)...
to coincide with the afternoon forecast package we have issued
Severe Thunderstorm Watch 81 for Bastrop...Lee...Fayette..and
Lavaca counties. Thunderstorms have begun to form along the cold
front and will continue to move toward the southeast. Skies
cleared in the area earlier today and temperatures warmed into the
lower 80s. Moisture was still plentiful with dew point
temperatures in the upper 60s and low 70s. Model soundings show
cape approaching 4000 j/kg and a weak cap. Steep midlevel lapse
rates and effective shear near 35 knots will support rotating
updrafts and large hail will be possible. Damaging winds are also
possible and we can not rule out a tornado.

Beyond the pre-first period. Upper air analysis this morning
showed a negatively tilted trough extending from western Kansas to
East Texas. The trough axis was east of our County Warning Area with west-
northwesterly flow over US. At the surface a cold front extended
from a low over Oklahoma to near San Angelo and back toward
Midland. A dryline extended southward across Edwards and Kinney
counties. Winds across the region were turning cyclonically from
northwesterly to southwesterly. Moisture was still plentiful with
dew point temperatures in the middle to upper 60s east of the
dryline. The upper low will progress to the east and the flow will
become zonal across Texas. There is a slight chance for
thunderstorm this afternoon and if there are any storms they will
likely continue into the first period. Conditions over our eastern
counties remain favorable for strong to severe storms...so if
there are any storms they may be strong to severe. The cold front
is expected to move through our area this evening and this will
bring our rain chances to an end. Skies will be clear and cooler
air will filter in. Monday winds will turn from the north to
northeast as high pressure moves to the east across North Texas.
Monday night winds will begin to turn to the southeast...mainly
across the west...beginning moisture return.

Long term (tuesday through sunday)...
an upper level ridge will build from Texas to the central rockies
in response to a low dropping southward along the West Coast. The
low level flow will be from the southeast with strong moisture
return from the Gulf. On Tuesday before the upper flow becomes
anticyclonic...a 250mph 100kt jet will extend across Texas. This
along with the deepening low level moisture may be enough to
produce some showers and thunderstorms. Wednesday and Thursday we
may see the dryline move into our western area and produce some
thunderstorms. Friday and Saturday a cold front will move in from
the northwest bringing another chance for showers and
thunderstorms. Sunday drier air will return from the north.

&&

Preliminary point temps/pops...
Austin Camp Mabry 55 74 55 77 64 / 20 0 10 20 10
Austin Bergstrom international Airport 54 72 52 77 62 / 20 0 10 20 10
New Braunfels Muni Airport 55 74 54 78 64 / 20 0 10 20 20
Burnet Muni Airport 52 73 53 76 63 / 10 0 10 20 10
del Rio International Airport 59 76 59 81 65 / - 10 20 10 20
Georgetown Muni Airport 52 73 53 77 63 / 20 0 10 20 10
Hondo Muni Airport 56 75 55 77 65 / 10 - 10 20 20
San Marcos Muni Airport 56 73 54 77 62 / 20 0 10 20 20
La Grange - Fayette regional 56 74 56 78 63 / 30 0 10 20 10
San Antonio International Airport 57 74 56 78 65 / 10 - 10 20 20
Stinson Muni Airport 58 74 56 77 65 / 10 - 10 20 20

&&

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

$$

Mesoscale/aviation...24
synoptic/grids...26
public service/data collection...33

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