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

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FXUS64 KEWX 241123
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
623 AM CDT Thu May 24 2018

.UPDATE...
12Z Aviation update below.

&&

.AVIATION...
Stratus has developed across much of the CWA overnight and early this
morning and is currently producing a mix of IFR to MVFR ceilings.
Ceilings will gradually improve back to VFR between 14Z-16Z as the
stratus mixes out. Once again isolated SHRAs and TSTMs are possible
east of I-35 and I-37 this afternoon. Can`t rule some of this
activity near AUS late afternoon, but confidence is low. In addition,
models indicate upstream convection possibly reaching just northwest
of DRT this evening.

&&

.PREV DISCUSSION... /ISSUED 333 AM CDT Thu May 24 2018/

SHORT TERM (Today through Friday)...
The Subtropical Ridge continues to build over western Texas today
and then expands a little to the east on Friday. Similar to the last
few days, diurnally driven showers and thunderstorms are expected
east of I-35 today where deeper moisture resides with heating and
lifting from the seabreeze. With the expansion of the Ridge, the
showers and thunderstorms will stay east of Highway 77 on Friday.
Cannot rule out isolated showers and thunderstorms coming off the
Serranias del Burro each evening. A couple of hi-res models show
isolated showers and thunderstorms over the Edwards Plateau Friday
afternoon. For now, will go with 10 POPs and no mention for that area
as a capping inversion should hold. Slightly above normal
temperatures continue with a warming trend.

LONG TERM (Friday Night through Wednesday)...
The Subtropical Ridge shifts to the east across Texas with the axis
generally from northern Mexico to over our area during the Memorial
Day weekend into early next week, then strengthens (500 MB heights
around 5930M) middle to late next week. Moisture levels decrease
somewhat along with increasing subsidence from the Subtropical Ridge
and a capping inversion from warming mid level temperatures. As a
result, rain is not expected. Daytime mixing with warming mid level
temperatures (850 MB warming to 23C east to 29C west) and drying
soils enable a significant warmup resulting in high temperatures
around 10 degrees above normal. By the weekend, highs around 100 to
103 are expected along the Rio Grande, then spreading to the I-37
corridor from San Antonio south by Memorial Day. These highs will
continue all of next week with ensemble guidance indicating a
potential for even hotter temperatures. Good mixing with drier air
aloft will keep maximum afternoon heat index values below 105. Being
that the daytime temperatures will be the hottest so far this year,
those participating in outdoor activities this Memorial Day weekend
should drink plenty of water and take breaks in a shaded or air
condition area. Should the system in the Gulf of Mexico develop
into a tropical or subtropical low (NHC has increased chances to 70
percent as of last evening), any impact on South Central Texas would
be to enhance the heating and drying.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              90  72  93  72  96 /  10  -   -    0   0
Austin Bergstrom Intl Airport  90  70  93  71  95 /  10  -   -    0   0
New Braunfels Muni Airport     92  70  94  70  96 /  10   0  -    0   0
Burnet Muni Airport            90  70  93  70  95 /  -    0  -    0   0
Del Rio Intl Airport           95  74  98  74 102 /  -    0   0   0   0
Georgetown Muni Airport        89  71  93  71  95 /  10  -   10  -   -
Hondo Muni Airport             93  71  96  69  99 /  -    0   0   0   0
San Marcos Muni Airport        91  70  93  70  96 /  10   0  -    0   0
La Grange - Fayette Regional   89  71  92  71  94 /  30  10  10  -   -
San Antonio Intl Airport       92  73  94  72  97 /  -    0  -    0   0
Stinson Muni Airport           95  73  96  72  99 /  -    0  -    0   0

&&

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

&&

$$

Mesoscale/Aviation...Runyen
Synoptic/Grids...04



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