206
FXUS64 KEWX 121246
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
746 AM CDT Sun May 12 2024

...New UPDATE...

.UPDATE...
Issued at 739 AM CDT Sun May 12 2024

Adjusted PoPs through today into this evening according to latest
radar trends and forecast guidance. Greatest rainfall and strongest
convection that is currently situated along our northern boundary
with FWD/SJT CWAs should mainly pivot north and northeastward away
from our area. However, we`ll need to watch for any straggler cells
still across our northern counties. This afternoon, attention then
may turn more towards areas east of I-35 into the coastal plains
where new convection could try to develop with daytime heating. A
few hi-res models, like the RRFS, pick up on this potential. If
storms do fire within this area, this could be the best opportunity
for a strong to severe cell within our CWA. San Antonio and west
looks to be mainly dry on this Mother`s Day with temperatures into
the upper 80s and 90s.

&&

.SHORT TERM...
(Today through Monday)
Issued at 207 AM CDT Sun May 12 2024

The latest GOES 16 IR imagery shows a 500mb closed low over
southwestern Colorado. At the surface, easterly flow has resumed
after a cooler and comfortable day by early to mid-May standards.
Moisture should start to work back in, but dewpoints should start to
rise once again overnight and get back into the 70s by midday
Sunday. Mother`s Day will be a muggy day, but on the cooler side
over the eastern half of the region as cloud cover will be hard to
break. Further west, highs should climb back into the mid to upper
80s and lower 90s once again along the Rio Grande as low clouds
break towards the afternoon hours.

The short term forecast is a messy one, as precip chances look
difficult to predict through Sunday night. Confidence remains low on
timing of any thunderstorms and where they ultimately develop. Light
showers and occasional drizzle should continue through the morning
hours as isentropic ascent is realized with east to southeasterly
flow on the 300k surface. By the afternoon, as instability
increases, some strong to severe storms will be possible. The latest
day 1 outlook from the Storm Prediction Center places the Hill
Country, I-35 Corridor, and Coastal Plains within a Level 1 of 5
Risk, while a small portion of the CWA from east of Austin to La
Grange and northward is in a Level 2 of 5 Risk. All modes of severe
weather are possible, but at this time, the greatest threat appears
to be large hail. Any discrete storm that can tap into rich boundary
layer moisture could also start rotating, with a tornado or two also
possible. Ultimately, the greater severe threat for Sunday lies just
to our east, but conditions should be monitored closely nonetheless.

Monday brings a greater threat for widespread strong to severe
storms as the associated 500mb trough starts to move eastward. On
it`s southern periphery, a potent shortwave will round its base and
move through south Central Texas. A cold front will approach from
the northwest and work through the entire CWA by sunset Monday. SPC
places the eastern Hill Country, I-35/I-37 Corridor, and Coastal
Plains within a Level 2 of 5 Risk on Monday. The primary concern
looks to be large to very large hail along with damaging winds, but
a tornado or two cannot be ruled out along the boundary early in the
afternoon. The RRFS, HRRR, FV3, and NSSL WRF are all on board with
afternoon convection. The real item up in the air is what happens
before the lunch hour. Some members of the HREF develop early
morning convection over the Hill Country and spread it eastward
while others show little to no activity at this time. For now, focus
will be on the afternoon storm chances as instability, shear, lift,
and lapse rates will be highest within this time frame, but morning
storm chances will have to be monitored as well.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 207 AM CDT Sun May 12 2024

A cold front will be moving out of the area with possibly some
showers or thunderstorms Monday night over the Coastal Plains before
pushing east overnight. Dry conditions are then expected for Tuesday
through Wednesday morning as upper ridging moves overhead. Above
normal temperatures are expected Tuesday afternoon from the mid 80s
in the northeastern portion of the area to the upper 90s and 100
degree mark in the west along the Rio Grande. A trough located just
off the southern coast of California on Tuesday will move east
towards the Plains Wednesday and Thursday. This will bring the next
chances for precipitation to the area late Wednesday afternoon
through Thursday night. There remains the potential for some severe
thunderstorms and heavy rainfall with this activity. The current
forecast places the heaviest rain potential over the northeastern
portion of the CWA which is also where WPC has placed a level 2 of 4
risk for excessive rainfall.

For now, the forecast remains on the dry side Friday through the
weekend although there is decent spread in model guidance after the
mid-week system. Some low precipitation chances may be introduced
for next weekend in the coming forecasts. A warming trend is
possible late week into next weekend.

&&

.AVIATION...
(12Z TAFS)
Issued at 602 AM CDT Sun May 12 2024

Very few changes from the going forecast. Confidence remains quite
low on timing and placement of TS today. Will stick with the PROB30
groups at AUS, SAT, and SSF and introduce PROB30s for tomorrow AM at
AUS and SAT. Winds should remain less than 10 kts for the most part
out of the southeast to east-northeast by late tonight. Ceilings
should remain IFR/MVFR through midday before lifting to MVFR/VFR. No
other significant changes at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              72  87  67  89 /  30  60  10   0
Austin Bergstrom Intl Airport  71  87  65  89 /  30  60  10   0
New Braunfels Muni Airport     72  89  67  91 /  10  60  10   0
Burnet Muni Airport            70  85  63  87 /  10  30   0   0
Del Rio Intl Airport           74 101  70 101 /  10  10   0  10
Georgetown Muni Airport        70  86  64  87 /  30  60   0   0
Hondo Muni Airport             73  92  66  94 /  20  30   0   0
San Marcos Muni Airport        71  88  65  89 /  20  60  10   0
La Grange - Fayette Regional   73  86  67  88 /  30  60  20   0
San Antonio Intl Airport       73  90  68  92 /  10  40  10   0
Stinson Muni Airport           74  91  69  93 /  10  40  10   0

&&

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

$$

Short-Term...Brady
Long-Term...27
Aviation...MMM