874
FXUS64 KEWX 251711
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1211 PM CDT Sat May 25 2024

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 216 AM CDT Sat May 25 2024

Low clouds are in the process of developing across the central areas
of the CWA overnight. Southeasterly flow also prevails with
temperatures in the upper 70s to lower 80s at the present time. Low
temperatures later by morning will be mostly in the middle to upper
70s for most locations. The main concern of the short-term portion of
the forecast will be the continued early season heat with highs
today in the middle 90s to 107 degrees. The main issue will be the
elevated dewpoints remaining in the peak heating periods leading to
afternoon heat index values in excess of 108 degrees for many
locations. Have issued a Heat Advisory today to much of the CWA
outside of the Hill Country. With the dryline remaining more to our
west today, the southwestern CWA is in the advisory today. The ARW
shows some isolated convection today but it is the only CAM that
shows any activity in our area. Will keep the forecast dry with the
consensus of the model guidance.

Lows tonight will be back in the 70s to near 80 degrees. For
tomorrow, another hot day is expected with highs in the upper 90s to
108 degree range. The dryline should push more to the east tomorrow
which will likely keep heat index values in the Rio Grande Plains
and southwestern CWA from reaching advisory criteria. However,
another Heat Advisory will likely be needed for the I35 corridor and
Coastal Plains tomorrow.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 216 AM CDT Sat May 25 2024

The base of a Central/Northern Plains upper trough lifts NE to the
Ark-la-tex by 00Z Monday, leading to the farthest eastward intrusion
of the dry-line over South Central TX in this heatwave pattern. This
leaves Gulf moisture depleted over most of the CWA, and the return
flow and morning low clouds may not get to progress as far inland as
they have prior mornings. This means another rapid late morning burn
off of the low clouds and another day of record heat and high
heat index values for Monday. Late in the day some changes aloft over
Mexico could increase mid level moisture, while at the surface a weak
cold front arrives into Central TX. The past few runs of the
deterministic GFS show two areas of destabilization, one possibly
storm initiation on the higher terrain slopes of Mexico and another
from the frontal convergence over the I-35 corridor. It`s possible
that only a few storms develop out of this region as the air aloft
should still be mostly stable. Then once a storm develops, there
should be a favorable condition for strong downdrafts in the hot and
dry mixing layer. This could further reduce the amount of convection
that could occur Monday evening. The GFS precipitation placement
looks good, but we`ll stick to the more conservative PoP numbers
closer to the NBM.

Tuesday, a shortwave disturbance moves through TX and generates
scattered convection as a more unstable NW flow aloft pattern
develops over Central TX. The added clouds, and storm downdrafts
should further establish the modified low level frontal air spilling
south and get us back to more typical late May MaxT values. Yet
another wave of convection is depicted for Wednesday night into
Thursday. As is typical with NW flow patterns, the Central TX
counties will again get the best instability and rain potential with
these rounds of convection. Additional late spring rounds of
convection will remain possible in this rather vague upper pattern
through the 7-day forecast, but shortwave identification and storm
timing will become less predictable.

&&

.AVIATION...
(18Z TAFS)
Issued at 1209 PM CDT Sat May 25 2024

MVFR ceilings have largely dissipated this morning and some HZ is
expected to linger through the day with visibility generally
remaining around 6SM. Breezy south to southeasterly wind will be seen
through the evening. MVFR ceilings redevelop over the I-35 sites
around 07Z Sunday.

&&

.CLIMATE...
(RECORD HIGHS THIS WEEKEND)
Issued at 219 AM CDT Sat May 25 2024

         SAT        SUN        MON
        05/25      05/26      05/27
--------------------------------------
AUS   100/2011    97/2018   100/2011
ATT   100/2011    99/2018   100/2011
SAT   103/1989   100/1989   100/2011
DRT   104/2011   106/2018   106/2018

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              76  98  75  99 /   0   0   0  10
Austin Bergstrom Intl Airport  75  98  74  99 /   0   0   0  10
New Braunfels Muni Airport     76 100  75 101 /   0  10   0  10
Burnet Muni Airport            74  98  72  97 /  10   0   0  10
Del Rio Intl Airport           82 109  74 110 /   0   0   0  10
Georgetown Muni Airport        74  98  73  98 /  10   0   0  10
Hondo Muni Airport             75 104  74 104 /   0   0   0  10
San Marcos Muni Airport        75  99  75 100 /   0  10   0  10
La Grange - Fayette Regional   77  96  77  97 /   0  10   0  10
San Antonio Intl Airport       76 103  76 101 /   0   0   0  10
Stinson Muni Airport           77 103  77 102 /   0   0   0  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT this evening for Atascosa-Bastrop-
Bexar-Caldwell-Comal-De Witt-Dimmit-Fayette-Frio-Gonzales-Guadalupe-
Hays-Karnes-Kinney-Lavaca-Lee-Maverick-Medina-Travis-Uvalde-Val
Verde-Williamson-Wilson-Zavala.

&&

$$

Short-Term...29
Long-Term...18
Aviation...27