463
FXUS64 KEWX 200537
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1237 AM CDT Mon May 20 2024

...New AVIATION...

.SHORT TERM...
(Tonight through Monday night)
Issued at 137 PM CDT Sun May 19 2024

Morning cloud cover held on a bit longer than yesterday but still
expecting highs today to reach into the 90-104 degree range across
the area with the hotter temperatures expected along the Rio Grande.
Dewpoints along the Rio Grande remain in the lower 70s but should
mix out a bit later today which could lead to some elevated fire
weather conditions given southeast flow near 15 mph with slightly
higher gusts. The short-term period will remain rain free and warm.
Highs tomorrow will be back into the 90-105 degree range. Slightly
higher dewpoints in the Rio Grande will lead to less of a fire
weather concern, but afternoon heat index values will approach 107-
110 degrees which is just below Heat Advisory criteria. Lows tonight
will range from near 70 in the Hill Country to the upper 70s in the
Rio Grande. For tomorrow night, with slightly higher dewpoints,
expect low temperatures to be warmer, in the middle 70s to near 80
degrees. Can`t rule out some patchy fog in the Coastal Plains
tonight but not expecting widespread impacts there.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 137 PM CDT Sun May 19 2024

On Tuesday afternoon, a 1-2 Sigma 500mb ridge will be centered just
south of our region over northeastern Mexico. In combination with
700mb temperatures in the 12-16C range and strong surface heating
under the associated thermal ridge, afternoon highs will easily top
out in the 90s for all locations, with highs in the 100-105 range
west of the San Antonio metro over the Southern Edwards Plateau and
Rio Grande Plains.

By early Wednesday, the ridge axis should slide east of our region,
opening the door for mid to late week afternoon and early evening
thunderstorms, especially over the Southern Edwards Plateau and Hill
Country. The dryline should have a role in convective activity each
afternoon, sliding eastward each afternoon. With SBCAPE in the 2000-
3000 J/kg range, steep mid-level lapse rates in the 7.5-8.5 C/km
range, and 0-6km deep layer shear of 40-50 kts each afternoon,
thunderstorms are possible if they can break through a moderately
strong cap. A series of shortwaves may help to spark these storms
despite the strong capping inversion each afternoon, but it will be
highly dependent on the timing of said shortwaves. Storms that do
develop could quickly turn severe with large hail and damaging winds
being the primary hazards Wednesday afternoon/evening through Friday
afternoon/evening. The heat is expected to continue each day despite
the increased rain chances, with widespread highs in the 90s to
around 105 along the Rio Grande. While record highs are unlikely at
AUS, ATT, and SAT, Del Rio has a good shot a breaking record highs
most days through the extended forecast.

Memorial Day weekend is shaping up to be very hot with highs in the
mid to upper 90s east and in the 100-108 range out west. Factoring
in heat indices in the 108-115 range and heat advisory products are
looking increasingly likely for most locations outside of the Hill
Country and Southern Edwards Plateau by late week.

&&

.AVIATION...
(06Z TAFS)
Issued at 1228 AM CDT Mon May 20 2024

Southeasterly flow in the boundary layer will continue during this
period. MVFR/IFR ceilings will develop tonight first in Austin and
San Antonio and later at DRT. Clouds will dissipate by late morning
with VFR conditions through the afternoon and evening. Southeasterly
winds will be 10 to 15 kts through the period at all terminals.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              92  75  92  76 /   0   0   0   0
Austin Bergstrom Intl Airport  92  74  92  76 /   0   0   0   0
New Braunfels Muni Airport     95  74  95  75 /   0   0   0   0
Burnet Muni Airport            91  73  90  75 /   0   0   0   0
Del Rio Intl Airport          105  79 105  80 /   0   0   0  10
Georgetown Muni Airport        91  73  90  75 /   0   0   0   0
Hondo Muni Airport             97  74 100  75 /   0   0   0   0
San Marcos Muni Airport        93  73  93  75 /   0   0   0   0
La Grange - Fayette Regional   91  76  89  76 /   0   0   0   0
San Antonio Intl Airport       94  75  95  76 /   0   0   0   0
Stinson Muni Airport           96  76  96  77 /   0   0   0   0

&&

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

$$

Short-Term...29
Long-Term...MMM
Aviation...05