528
FXUS64 KEWX 181814
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
114 PM CDT Sat May 18 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Tonight through Sunday night)
Issued at 112 PM CDT Sat May 18 2024

Zonal flow to slight ridging prevails aloft and as a result the
short-term forecast period will be mostly quiet. Morning fog has
given way to clear skies across all of South-Central Texas early
this afternoon. These mostly clear skies should prevail for the
remainder of the day for much of the area outside a few clouds
possible in the Coastal Plains later today with peak heating. High
temperatures today will be near 90 in the northeast up into the 100-
104 degree range in the Rio Grande Plains. Some return of low clouds
and patchy fog can be expected tonight for mainly the eastern areas
with lows in the upper 60s to middle 70s. Mostly clear skies will
then return by the early afternoon with high temperatures similar to
today. Surface winds may be a bit more breezy out west and could
create some elevated fire weather conditions mainly for the Edwards
Plateau. Lows will be back in the upper 60s to middle 70s for most
locations across the area tomorrow night.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 112 PM CDT Sat May 18 2024

There`s really no other way to put it than it`s going to be hot for
at least the next week plus as 500mb ridging builds in over northern
Mexico. One caveat: we will be on the northern periphery of this
strengthening ridge, so by the middle to end of the upcoming week,
the door may be opened to some northwesterly flow aloft within the
large scale pattern which could bring some rain and storm chances
back into the picture. The CPC places most of the region in a 70-80%
chance for above normal temperatures through the 6-10 period which
goes out through late May.

Taking a look at GFS/ECMWF ESAT tables indicates 500mb temperatures
will be within the 97th to 99th percentile Monday afternoon through
Tuesday afternoon, and 700mb temperatures will be equally anomalous
if not even more significant for mid to late May, as starting
Tuesday afternoon and continuing through Wednesday afternoon,
they`ll be within the 99th percentile to climatological maximum for
mid-late May. Another item to note is the dry soils over the western
CWA, particularly the Rio Grande Plains and Southern Edwards
Plateau, where NASA SPoRT LIS 0-100cm soil moisture is between 10
and 30% compared to the very wet soils over portions of the Coastal
Plains and the northern I-35 Corridor between San Marcos and
northern Williamson County. Have opted to lean more towards the NBM
25th/50th percentile for Max T`s over the eastern CWA to account for
the wetter soils. It`ll still be very hot, and in fact, the newest
NWS product available for the entire CONUS as of earlier this month,
HeatRisk, highlights a good chunk of our area within the Moderate to
Major categories Tuesday-Thursday, with Wednesday and Thursday
exhibiting Extreme risk for portions of the Rio Grande Plains and
Winter Garden Region into Dimmit, Zavala, and Maverick Counties.
Most of this is likely due to the early season nature of this
heatwave and folks not being acclimated quite yet. Tuesday and
Wednesday will likely flirt with heat indices in the 105-115 range
over the Rio Grande Plains, with some 100-105 range heat indices
over the I-35 Corridor and Coastal Plains. That risk for higher heat
indices may increase even further by late week, where Thursday and
Friday could potentially result in heat products for the I-35
Corridor, Rio Grande Plains, and Coastal Plains. Record highs look
like a good bet at Del Rio, but at the other sites, we`ll likely
remain just below record highs through the week.

Last, but not least, as mentioned above, we could transition into
more of a northwest flow pattern by late week into next weekend,
with rain and storm chances developing over the Hill Country and
spreading southeastward into the I-35 Corridor each day. For now,
the main focus will be on this early season heatwave.

&&

.AVIATION...
(18Z TAFS)
Issued at 1154 AM CDT Sat May 18 2024

VFR conditions are now prevailing at all airports and will continue
to do so for the remainder of the day and evening hours. There is a
small window of possible MVFR/IFR ceilings returning to the I35 sites
tomorrow morning and will include that in the TAFs. Otherwise,
south/southwest flow can be expected for much of the period. Could
see some slightly more breezy conditions for DRT tomorrow afternoon
as low-level winds increase a bit.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              71  92  72  91 /   0   0   0   0
Austin Bergstrom Intl Airport  70  90  70  92 /   0   0   0   0
New Braunfels Muni Airport     70  93  71  94 /   0   0   0   0
Burnet Muni Airport            70  90  70  89 /   0   0   0   0
Del Rio Intl Airport           76 105  76 106 /   0   0   0   0
Georgetown Muni Airport        70  89  70  89 /   0   0   0   0
Hondo Muni Airport             70  96  71  98 /   0   0   0   0
San Marcos Muni Airport        69  92  70  93 /   0   0   0   0
La Grange - Fayette Regional   71  90  72  89 /   0   0   0   0
San Antonio Intl Airport       71  93  73  95 /   0   0   0   0
Stinson Muni Airport           72  94  74  96 /   0   0   0   0

&&

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

$$

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