492
FXUS64 KEWX 130007 AAA
AFDEWX

Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
707 PM CDT Sun May 12 2024

...New AVIATION...

.SHORT TERM...
(Tonight through Monday night)
Issued at 205 PM CDT Sun May 12 2024

...Severe thunderstorms possible Monday afternoon mainly along and
east of the I-35 corridor with large to very large hail, and strong
damaging winds as the primary hazards...

A warm front is lifting northward across the state and majority of
the rain and elevated thunderstorm activity (positioned north of
this boundary) has remained outside of our region across the Fort
Worth, Houston, and San Angelo CWAs. Outside of this, we have only
see some spotty showers with few occasional lighting strikes. For
this afternoon, best chances for activity within our region will
align to the east of I-35 in the coastal plains. Instability is
starting to really build across the southern coastal plains where
temperatures (e.g. Kenedy) have climbed into the upper 80s and low
90s thanks to breaks in the cloud cover. Some of the latest CAM
guidance do show the possibility for surface based convection over
the coastal plains later this afternoon. If the case, an isolated
strong to severe storm may be possible. Clouds keep temperatures
more at bay over the rest of the area except along the Rio Grande
where temperatures should climb into the 90s as well. The forecast
outside of the locations east of I-35 look to stay dry during the
rest of Mother`s Day with only a low end chance for a shower.

A very warm and humid night will be expected tonight. Clouds with
low stratus will thicken back up as well through the night. A weak
shortwave pivoting around the base of the upper low to the north
could possibly spark an isolated thunderstorm that some CAMs have
latched onto through the overnight that could move southwest to
northeast across the region. Confidence regarding this solution is
low and will limit PoPs overnight to the 15 to 25 percent range.
However, if a storm does form, environmental conditions do support
some potential for this cell to become rather strong to perhaps
severe.

Greatest confidence for isolated to scattered severe thunderstorms
occurs Monday afternoon into Monday evening with forcing from an
approaching/arriving cold front. The most favored locations focus
from near and east of the I-35 corridor. Plenty of instability
remains and will increase as we head into the afternoon with the
faster rise in temperatures compared to today where the clouds
lingered the most. Low and mid-level lapse rates also steepen to
around or above 7.5 C/km. Deep layer shear will also be plenty to
support sustained organized severe weather. The low-level shear
profiles are a bit lackluster and keep the tornado threat more
minimal compared to the hazards for large to very large hail and
damaging winds. Storms would also remain capable of producing
intense rainfall rates despite quick storm motions. While we have
not received nearly the rainfall as our neighboring CWAs, some
isolated flooding could be possible where these heaviest rainfall
rates do occur. Storms should push quickly east-southeastward and
out of the region completely by around 10 pm. The rest of Monday
night should finish off dry with some cooler air filtering across
the region with the northeast to east-northeasterly winds behind
this front. Some Hill Country towns could dip below 60 degrees
during early Tuesday morning.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 205 PM CDT Sun May 12 2024

Fair weather is expected Tuesday through the first half of Wednesday
as weak upper level ridging builds in behind the departing upper
low. Attention then turns towards a west coast trough that will push
east into the Plains mid to late week. Some shortwave energy out
ahead of the main trough may bring chances for showers and storms to
south-central Texas as early as Wednesday afternoon/evening, with
chances continuing through the day Thursday. Both severe
thunderstorms and locally heavy rainfall appear possible with this
system, with plenty of CAPE/shear and above normal PWATs. However,
confidence is low regarding storm placement and coverage, with
indications that the greatest coverage of convection could be to the
north and east of our area.

There is some uncertainty regarding the evolution of the upper level
pattern behind this system as some models show a second
trough/shortwave sitting over northern Mexico which would then eject
east across Texas over the weekend, while others show ridging
beginning to build in heading into next week. The current forecast
is for a warming trend with slight chances for precipitation, though
PoPs will likely need to be adjusted depending on which upper level
pattern the models begin to favor for this period.

&&

.AVIATION...
(00Z TAFS)
Issued at 642 PM CDT Sun May 12 2024

IFR cigs are forecast to continue at KAUS through around midnight.
Then, LIFR cigs are forecast to develop overnight into Monday
morning. For KSAT. KSSF and KDRT, VFR conditions are forecast through
at least midnight before cigs lower to IFR category. A frontal
boundary is forecast to push across the local area mid-day on Monday
to bring chances of rainshowers and Isolated thunderstorms over those
locations. Added Prob30 groups to indicate that probability for KAUS,
KSAT, and KSSF. VFR conditions return to all terminals by 22Z or so.
Light to moderate winds from the west-northwest are forecast in the
wake of the frontal boundary.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              72  86  63  90 /  10  40  10   0
Austin Bergstrom Intl Airport  72  87  63  89 /  20  40  10   0
New Braunfels Muni Airport     73  88  63  92 /  20  40  10   0
Burnet Muni Airport            69  84  62  88 /  10  30   0   0
Del Rio Intl Airport           73 101  69 101 /  10  10   0   0
Georgetown Muni Airport        69  85  62  87 /  20  30  10   0
Hondo Muni Airport             73  93  63  94 /  20  30   0   0
San Marcos Muni Airport        72  87  61  90 /  10  40  10   0
La Grange - Fayette Regional   74  85  65  88 /  30  60  20   0
San Antonio Intl Airport       74  90  64  92 /  20  30  10   0
Stinson Muni Airport           74  90  66  93 /  20  30  10   0

&&

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

$$

Short-Term...17
Long-Term...29
Aviation...17