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

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FXUS64 KEWX 290526 AAE
AFDEWX

Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
1226 AM CDT Mon May 29 2017

.AVIATION.../06Z Update/
Currently seeing VFR conditions with -RA/-SHRA across the east.
Still have a few lightning strikes across the area, but none
currently at the terminals. Models continue to show MVFR cigs
developing later this morning and even some IFR. If we continue to
see the mid and high clouds across the area we should not see rapid
onset of low clouds. Have included in the forecast and will need to
monitor for developing trends over the next several hours. Winds
should remain NNE-E at 5 to 10 knots. The other major issue is the
development and timing of showers and thunderstorms not only tonight,
but on Monday as well. Looks like next shortwave is now producing
showers and thunderstorms across the northern Hill Country and
northern Edwards Plateau at this time. This convection will move E-SE
across the area this morning. Could see convective wind gusts to 35
knots and penny to dime size hail with the strongest cells. Will need
to watch developing trends and update the forecast as needed. should
see a return to MVFR conditions after 17Z and continue into Monday
evening, before another round of MVFR cigs develop. Winds will be
E-SE near 7-10 knots.

&&

.PREV DISCUSSION... /ISSUED 1103 PM CDT Sun May 28 2017/

UPDATE...
We have allowed the Severe Thunderstorm Watch for the southwest CWA
to expire at 11 PM, as stronger convection has shifted into the CRP
CWA and is expected to stay there overnight. Update out.

PREV DISCUSSION... /ISSUED 1008 PM CDT Sun May 28 2017/

UPDATE...
We extended the Severe thunderstorm Watch until 11 PM for southwest
counties and cancelled the remainder of the area. Storms should
continue to build into the instability axis to the south across the
CRP CWA, where an MCS could develop overnight. Farther north, the
cold front at 10 PM was located just south of a Del Rio to San
Antonio to Giddings line and will stall later tonight across far
southern areas of the CWA or into the CRP CWA. Have lowered pops for
the remainder of the night for much of the northern 2/3rds of the
CWA where conditions have stabilized and re-adjusted hourly T/Td.

PREV DISCUSSION... /ISSUED 657 PM CDT Sun May 28 2017/

AVIATION...
Scattered to Numerous SHRA/TSRA continued across the Hill Country,
Central Texas, and the Austin area. These will gradually push to the
E/SE across the remainder of South Central Texas as a surface trough
currently developing between San Antonio and Del Rio shifts E. Have
gone with TSRA at KAUS to start the TAF period, TEMPO at KDRT for
00Z-02Z, and KSAT/KSSF for 02Z-06Z. After that chances are uncertain
as surface trough focuses best chances southeast of I-35. VFR CIGs
will prevail, except brief MVFR CIGs/VSBYs in SHRA/TSRA. Some areas
of MVFR/IFR CIGs may develop overnight into Monday morning. CIGs will
lift to VFR midday on Monday. Wind gusts up to 60 KTs and GR/GS are
possible in the strongest TSRA, otherwise winds will be 10 KTs or
less.

PREV DISCUSSION... /ISSUED 320 PM CDT Sun May 28 2017/

UPDATE...
We`ve issued a Severe Thunderstorm Watch for the entire CWA until 10
pm. Storms have developed along the front and will continue into the
evening. We have already issued a couple of Severe Thunderstorm
Warnings and expect this to continue.

PREV DISCUSSION... /ISSUED 250 PM CDT Sun May 28 2017/

SHORT TERM (Tonight through Monday Night)...
Upper air analysis this morning showed west-southwesterly flow over
TX with a trough from central Canada to the Four Corners. At the
surface, a cold front was moving into our northwestern counties.
Winds ahead of the front were from the east to southeast and dewpoint
temperatures were in the lower to middle 70s. The upper level trough
will move across TX during this period. With the upper flow nearly
parallel to the front, it will move slowly through the area tonight
and Monday. This will mean showers and thunderstorms will be likely
tonight and Monday. At the start of the period, model soundings show
CAPE around 4000 j/kg, but with 0-6 km wind shear only 20-30 kts.
This could produce strong to severe thunderstorms with large hail as
the mostly likely threat this evening. Atmosphere is fairly uniform
across the CWA, so where storms are worst will depend on how things
develop with small scale features that are not well resolved now.
Storms should weaken below severe strength by midnight. Expect
convection to continue overnight and during the day Monday. Monday
night chances will decrease with slight to low chance POPs.

LONG TERM (Tuesday through Sunday)...
The pattern will remain unsettled through the week with west-
southwesterly flow aloft. A series of short wave troughs will move
through the pattern bringing chances for convection. Wednesday night
and Thursday a stronger short wave will bring a better chance for
showers and thunderstorms and some higher rainfall totals. The
overall pattern will change little toward the end of the period and
low chances for convection will remain in the forecast until the end
of the forecast.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              69  82  67  85  68 /  70  50  30  40  30
Austin Bergstrom Intl Airport  69  81  66  85  67 /  70  50  30  40  30
New Braunfels Muni Airport     70  80  66  84  68 /  70  60  30  40  30
Burnet Muni Airport            67  80  65  83  66 /  60  40  20  30  30
Del Rio Intl Airport           70  84  69  84  70 /  60  30  30  30  40
Georgetown Muni Airport        68  81  65  83  67 /  70  40  30  40  30
Hondo Muni Airport             69  83  68  86  68 /  70  40  30  40  30
San Marcos Muni Airport        70  80  66  85  68 /  70  60  30  40  30
La Grange - Fayette Regional   71  81  68  85  69 /  70  70  30  40  30
San Antonio Intl Airport       70  82  68  85  70 /  70  50  30  40  30
Stinson Muni Airport           72  80  69  84  70 /  70  50  30  40  30

&&

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

$$

Mesoscale/Aviation...17
Synoptic/Grids...10



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