Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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FXUS64 KEWX 211508
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1008 AM CDT Sat Apr 21 2018

.UPDATE...
Areas of drizzle and light rain have developed mainly along and east
of Highway 281 this morning. Forecast soundings show a saturated
layer from the surface up to 725 mb with a capping inversion above
this layer. This should equate to continued drizzle/light rain with
very little chances for thunder. Went ahead and removed the thunder
wording from the forecast for the rest of the morning hours. After
18z, the cap does weaken and there could be some isolated
thunderstorms and will mention iso t with a chance of showers. The
best chances for thunderstorms will be tonight across the eastern
areas with the better forcing associated with the passage of the cold
front across the region.

&&

.PREV DISCUSSION... /ISSUED 645 AM CDT Sat Apr 21 2018/

AVIATION...
/12Z TAFS/
Currently the I-35 terminals are at IFR cigs and expect for this
trend to continue through this afternoon. Cigs will recover for a
short period of time in the afternoon before going back down again to
IFR cigs due to scattered showers and few thunderstorms passing
along the corridor. MVFR cigs are expected behind a cold front late
this evening into Sunday morning.

For KDRT, MVFR cigs will prevail through midday and then VFR for the
rest of the forecast period. A dry-line should be moving across KDRT
around 17Z and shifting winds from the southeast to a northwesterly
flow.

PREV DISCUSSION... /ISSUED 422 AM CDT Sat Apr 21 2018/

SHORT TERM (Today through Sunday)...
Plenty of cloud cover continues early this morning across south
central Texas. Surface observations show temperatures currently range
from the mid 50s in the Hill Country to near 70 along the Rio Grande.
A warm front is also noted across the Rio Grande plains.

Most of the hi-res models agree in showing a gradual increase in
showers and thunderstorms today as an upper low translates eastward
across the Texas panhandle into Oklahoma. It still appears most of
the lift will occur north of our region today. However, with a warm
front moving northward and central Texas remaining within an area of
weak lift, we will continue to mention a decent chance for showers
and thunderstorms today. A dryline will also move in from the west
this afternoon and may help initiate convection. A portion of our
area remains within a marginal risk for severe thunderstorms today.
This includes locations generally along and east of a Llano to
Hallettsville line. The primary severe weather concerns will be
large hail and damaging winds.

By late evening, a cold front will begin moving into the western
Hill Country. Several hi-res models suggest some convection will be
possible along the front as it progresses southward through the
region. We will keep a low chance for showers and storms in the
forecast this evening into the overnight hours as the front
progresses southward.

The forecast will remain dry on Sunday with surface high pressure in
place. We expect highs mainly in the 70 to lower 80s behind the
front.

LONG TERM (Sunday Night through Friday)...
The forecast for midweek looks dry as mid-level ridging briefly
builds in from the southwest. Another cold front will move through on
Wednesday and given fairly weak return flow ahead of the front, we
will only mention a low chance for showers and storms on Wednesday.
Southerly flow in the low-levels briefly returns on Thursday before
another cold front moves in early Friday. The operational GFS and
ECMWF models appear quite generous with precipitation amounts
associated with this front. At this time, we prefer to keep rain
chances low and see if this trend continues in subsequent model runs.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              73  54  77  54  82 /  40  20   0   0   0
Austin Bergstrom Intl Airport  73  54  76  52  81 /  50  20   0   0   0
New Braunfels Muni Airport     75  54  77  53  82 /  40  20   0   0   0
Burnet Muni Airport            74  51  73  50  79 /  40  20   0   0   0
Del Rio Intl Airport           88  57  84  58  85 /  -    0   0  -   -
Georgetown Muni Airport        72  52  74  51  80 /  40  30   0   0   0
Hondo Muni Airport             79  54  83  54  84 /  30  10   0   0  -
San Marcos Muni Airport        74  54  77  52  82 /  50  20   0   0   0
La Grange - Fayette Regional   73  56  76  53  80 /  60  50   0   0   0
San Antonio Intl Airport       75  55  78  55  83 /  40  10   0   0   0
Stinson Muni Airport           77  56  80  56  83 /  40  10   0   0   0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Mesoscale/Aviation...Oaks
Synoptic/Grids...Hampshire


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