Area Forecast Discussion Issued by NWS Austin/San Antonio, TX
000
FXUS64 KEWX 162322
AFDEWX
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
622 PM CDT Sat Mar 16 2024
...New AVIATION...
.SHORT TERM...
(Tonight through Sunday night)
Issued at 201 PM CDT Sat Mar 16 2024
Key Messages
* Isolated strong to severe storms with the main threat large,
possibly very large (>2 inches) hail late this afternoon and
evening.
* Locally heavy rainfall is possible with the main threat isolated
flooding
Showers and thunderstorms continue across portions of South-Central
Texas as activity continues to push east and north. Some of this
activity has tried to organize, but nothing more than pea sized hail
likely occurred this morning. High-res model guidance is in fairly
good agreement that additional activity is expected to remain
scattered this afternoon with the continued threat of some strong
storms. The focus for the short-term forecast then points to the
west as more widespread activity is expected to develop this evening
across the southern Edwards Plateau and Rio Grande Plains. A decent
shortwave on the southern periphery of the upper low can be seen on
water vapor imagery rotating eastward into northern Mexico and will
enter our region this evening. Some of this initial activity could
be severe with some possible significant hail per latest SPC day 1
outlook. This activity is expected to grow upscale into a complex as
it moves east over South-Central Texas.
While the initial threat will be severe storms there is some signals
in the latest high-res guidance for this to become a locally heavy
rainfall threat. Latest mean values for QPF with both the NBM and
HREF are near 1-2 inches for a large portion of the area with 90th
percentile values representing a reasonable worse case scenario near
4 inches for southern areas. This is also supported within the
Probability Matched Means of the SREF with a large area of 2-4
inches. If the isolated 4 inches does occur then some flooding would
be a concern and will message that possibility.
Widespread rainfall activity will end by the morning hours, but
additional scattered to possibly numerous showers and storms can be
expected on Sunday. This activity will primarily be an additional
half of an inch on average across the area. The forecast then dries
out further Sunday night with PoPs confined to the Rio Grande Plains
as the upper low pulls back to the west a bit. Temperatures will
continue to be in the 60s and 70s during the day with lows in the
50s and 60s tonight and in the 40s and 50s tomorrow night with less
cloud cover.
&&
.LONG TERM...
(Monday through Saturday)
Issued at 201 PM CDT Sat Mar 16 2024
The cut-off low remains across the Desert Southwest while an upper
level ridge develops across the Southern Plains Monday into Tuesday.
At the surface, high pressure lingers across the lower Mississippi
Valley through the period producing northeast to east flow across
most of South-Central Texas and southeast along the Rio Grande.
Increased moisture stays over the Rio Grande on Monday for the
probability of isolated to scattered showers. By Tuesday, conditions
look drier with slight chances for showers over Val Verde and
vicinity areas.
The cut-off low finally moves to the southeast as it opens and
travels across New Mexico and west Texas through Thursday. By this
time, there will be plenty moisture in place for isolated showers to
develop across the eastern half of South-Central Texas on Wednesday.
The activity could spread across the entire local area on Wednesday
evening into the overnight hours and continues into Thursday as an
upper level short wave and Pacific cold front moves across the local
area. Clearing begins from west to east mid to late morning with
sunny skies expected for most areas on Thursday afternoon.
Dry weather conditions are forecast for Friday into early next week.
Temperatures through the extended forecast period stay cool with
highs in the 50s to 70s with a warming trend starting on Wednesday
with highs in the 60s and 70s with highs on Thursday and Friday
ranging from the 70s to 80s.
&&
.AVIATION...
(00Z TAFS)
Issued at 622 PM CDT Sat Mar 16 2024
A tricky forecast period is in store as a stalled boundary (formally
a cold front) lingers across the area and an upper level disturbance
is expected to move into the area from Mexico. The result should be
the development of showers and thunderstorms late this evening and
through the overnight, beginning as early as 03z near KDRT and 06Z
near KSAT/KSSF. With that said, models have had poor performance
recently, likely at least partially due to the stalled boundary, and
therefore confidence in timing is low. With any storms overnight,
there will be potential for large hail and damaging wind gusts in
addition to the usual hazards of lightning, heavy rain, and poor
vis/cigs. Outside of precipitation, widespread IFR to possibly LIFR
cigs are expected overnight/early tomorrow morning, with slow
improvements during the day Sunday. After the boundary moves
slightly further south this evening, winds should generally be
northeasterly, with the exception of in/around thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 61 68 52 66 / 90 50 10 0
Austin Bergstrom Intl Airport 61 69 51 65 / 90 50 10 0
New Braunfels Muni Airport 61 71 53 67 / 90 60 0 0
Burnet Muni Airport 58 64 49 64 / 70 50 10 0
Del Rio Intl Airport 62 69 57 66 / 90 60 50 50
Georgetown Muni Airport 61 66 49 64 / 70 50 10 0
Hondo Muni Airport 60 71 52 66 / 90 60 0 10
San Marcos Muni Airport 60 70 51 65 / 90 50 0 0
La Grange - Fayette Regional 63 71 54 65 / 90 60 10 0
San Antonio Intl Airport 61 71 53 66 / 90 60 0 0
Stinson Muni Airport 62 71 55 67 / 90 60 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...29
Long-Term...17
Aviation...Gale