123
FXUS64 KEWX 231713
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1213 PM CDT Thu May 23 2024

...New AVIATION...

.SHORT TERM...
(Today through Friday)
Issued at 113 AM CDT Thu May 23 2024

Southeasterly flow off the Gulf of Mexico maintains a warm and humid
airmass over South Central Texas early this morning. This airmass
will persist across all areas today with the dryline remaining west
over all of our area, except Val Verde County. Expect little change
in high temperatures most areas, however better mixing of low clouds
should allow for a return of high temperatures above 100 farther
north up the Rio Grande to the Val Verde County area. Expect similar
heat index values today most areas. The highest values of 108 to 111
will be found generally along and south of US 57 and west of I-37
where a Heat Advisory will be issued for this afternoon into early
evening.

On Friday, the dryline mixes to the east into the Edwards Plateau
and the Rio Grande Plains. The drier airmass west of the dryline
will allow for even hotter high temperatures there, however heat
index values will be lower due to lower dewpoints. A strengthening
thermal ridge also brings hotter high temperatures and heat index
values east of the dryline. Another Heat Advisory is likely, this
time for portions of the I-35 corridor, including the San Antonio
area and possibly Austin area. Later forecasts will determine the
areal coverage for Friday`s Heat Advisory.

As far as chances of showers and thunderstorms, portions of the Hill
Country into Central Texas remain favored both days. Forcing by a
weak mid level impulse today and the dryline Friday afternoon along
with heating should generate showers and thunderstorms. However,
capping due to an encroaching Subtropical Ridge from the south
should keep activity mainly isolated. Forecast soundings show MLCAPE
of 2500 to 3500 J/kg and mid level lapse rates of 8.5 C/km today and
MLCAPE of 4000 J/kg on Friday. All hazards of severe storms are
possible with large to very large hail and damaging wind gusts the
main threats. PWs around 150% of normal could bring some high
rainfall rates with a threat of minor flooding.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 113 AM CDT Thu May 23 2024

  * Much of South Central TX is about to experience probably the
    hottest Memorial Day weekend of all time
  * Monthly high temperature record for May likely to be tied or
    broken at DRT
  * Heat Advisories and/or Excessive Heat Warnings are likely for
    much of the region through Monday

The negative impacts of below normal precipitation this year will
help with making the southern and western two-thirds of South Central
TX extraordinarily hot for this Memorial Day weekend. The driest
areas near the Rio Grande has already resulted in a tie of the
monthly high temperature record for May, and an even hotter weather
pattern looms ahead in the next few days. The pattern itself isn`t
particularly eye-catching with a somewhat flat ridge over TX and dry
air mixing down from westerly flow aloft and some downsloping
influences coming from the higher terrain to the west setting the
table.

Over our NE counties, high heat indices could still warrant a heat
advisory, but a more robust wet season will make the afternoon
ambient temperature more typical low to mid 90s for a stable weather
patten for late May. Nevertheless, the dryline should mix the
farthest east on Sunday, possibly leading to the first triple digit
MaxT day of 2024 and daily high temperature record if our forecast
verifies.

A final day of unusually hot weather is expected Monday, but northern
counties could get some relief should a cool front arrive in the
afternoon.

Friday`s dry-line could trigger isolated storms that could carry over
into the evening over parts of the Hill Country and Central TX, and
the next rain chance skips to Monday when a late day front tries to
cut into the TX heat. Each of these days could see some strong wind
gust potential, and perhaps a low threat for hail Friday evening.
Rain chances after Monday will be accompanied by a more typical late
May pattern, but a few strong storms could still develop as the
afternoon air will still be quite warm.

&&

.AVIATION...
(18Z TAFS)
Issued at 1210 PM CDT Thu May 23 2024

Besides some locations over the Hill County and southern Edwards
Plateau, most locations should begin the period with VFR conditions.
Any lingering MVFR ceilings should lift in the next hour or two with
VFR conditions through the evening. Low ceilings will redevelop
tonight across the eastern two thirds of the area, mainly staying
MVFR. Some IFR ceilings will be possible over the Hill Country by
sunrise, and will need to watch SAT for this potential. HZ continues
with occasional reductions to VSBY, however 6SM or higher will
generally be seen. Breezy southeasterly wind will be seen in the
eastern half of the area through this evening, with lighter wind at
DRT.

&&

.CLIMATE...
(RECORD HIGH TEMPERATURES THURSDAY THROUGH MONDAY)

         THU        FRI        SAT        SUN       MON
        05/23      05/24      05/25      05/26     05/27
------------------------------------------------------------
AUS    99/2008    99/1955   100/2011    97/2018  100/2011
ATT   100/2008   104/1925   100/2011    99/2018  100/2011
SAT    99/2008*  101/1989*  103/1989   100/1989  100/2011
DRT   105/2000   109/2000   104/2011   106/2018  106/2018

* TIED RECORD WITH MOST RECENT OCCURRENCE SHOWN

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              76  96  75  97 /   0  20  30   0
Austin Bergstrom Intl Airport  75  97  74  97 /   0  20  30   0
New Braunfels Muni Airport     75  99  74  99 /   0  10  10   0
Burnet Muni Airport            73  93  73  94 /   0  20  20   0
Del Rio Intl Airport           80 107  78 109 /   0   0  10   0
Georgetown Muni Airport        74  94  73  95 /  10  20  30   0
Hondo Muni Airport             75 103  74 104 /   0  10  10   0
San Marcos Muni Airport        75  98  74  97 /   0  20  20   0
La Grange - Fayette Regional   77  94  77  94 /   0  10  20   0
San Antonio Intl Airport       76 100  75  99 /   0  10  10   0
Stinson Muni Airport           77 101  76 101 /   0  10  10   0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT this evening for Atascosa-Dimmit-Frio-
Maverick-Zavala.

&&

$$

Short-Term...04
Long-Term...18
Aviation...27