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

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859
FXUS64 KEWX 251124
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
624 AM CDT WED MAY 25 2016

.AVIATION...
MVFR/IFR stratus is in place across the TAF sites this morning.
These conditions will continue through the late morning or early
afternoon hours before lifting into VFR. Showers and thunderstorms
will develop late this afternoon near KDRT and will mention VCTS
for the late afternoon and evening hours. Storm chances do exist
for the I-35 sites but chances were too low to mention at this
time. Southerly winds will prevail through the period with speeds
mainly between 10-15 knots. Another round of low ceilings are
expected tonight.

&&

.PREV DISCUSSION... /ISSUED 336 AM CDT WED MAY 25 2016/

SHORT TERM (Today through Thursday)...
Upper air analysis last evening showed a low amplitude ridge from
east Texas to the Great Lakes and a trough over the west coast.
The flow over Texas was from the southwest bringing Pacific
moisture across Mexico. At the surface, high pressure centered
over the central Gulf coast had the winds from the southeast.
Dewpoint temperatures were in the lower to middle 70s across our
CWA. The upper level trough will dig southward along the west
coast today and then move eastward along the US/Mexico border. The
upper flow over Texas will continue to be southwesterly. The low
level flow will also remain unchanged today. A dryline will move
toward our northwestern area tonight and this will likely bring
thunderstorms into our CWA. Forecast MU CAPE values will be
3000-4000 j/kg and deep layer wind shear 30-40 kts. There will
also be a substantial amount of CIN and this adds uncertainty to
the forecast. Storms may move off the mountains in northern Mexico
above the cap and into Texas. Any storms that do move in may be
strong to severe. The most likely threats will large hail and
damaging wind gusts with steep lapse rates in the hail gowth zone
expected. As the upper trough continues to move eastward Thursday,
a surface front will move through west Texas. This will mean a
continuing chance for thunderstorms. Convective parameters will
continue to be favorable for strong to severe storms Thursday and
these storms will push farther east to include the I-35 area. In
addition, continuing moist low level flow will increase PW values
to near or above two inches and this will bring locally heavy rain
into the forecast beginning Thursday afternoon. Locally heavy rain
will be possible over most of the eastern half of the CWA.

LONG TERM (Thursday Night through Tuesday)...
At the start of this period, convection will likely be ongoing
with severe thunderstorms and locally heavy rain possbile, as
descibed above, Thursday night. Storms will continue into early
Friday with strong to severe storms still possible mainly over the
eastern half of the CWA. The upper level trough will continue it`s
slow movement into the middle of the country Friday and Friday
night. The upper pattern will become nearly zonal Saturday and
remain that way through the end of the period. The low level flow
will also change very little through this period keeping abundant
moisture over the region. Weak short wave troughs will move
through the upper pattern, and along with the low level moisture,
will keep slight to low end chance pops in the forecast through
the end of the period. With no low level boundaries to focus
convection, no time looks any worse than any other time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              88  74  83  71  86 /  20  40  70  50  60
Austin Bergstrom Intl Airport  89  74  84  72  85 /  20  40  70  50  60
New Braunfels Muni Airport     90  74  84  72  85 /  20  40  70  50  50
Burnet Muni Airport            87  73  82  70  85 /  20  40  70  60  70
Del Rio Intl Airport           92  75  90  71  93 /  20  60  30  40  20
Georgetown Muni Airport        87  74  83  71  85 /  20  40  70  60  70
Hondo Muni Airport             90  74  87  72  89 /  20  50  60  60  40
San Marcos Muni Airport        88  73  83  72  85 /  20  40  70  50  60
La Grange - Fayette Regional   89  75  83  74  86 /  20  30  60  50  70
San Antonio Intl Airport       89  74  84  72  86 /  20  50  60  50  40
Stinson Muni Airport           91  75  86  74  88 /  20  40  60  60  40

&&

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

$$

Mesoscale/Aviation...Hampshire
Synoptic/Grids...05



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