512
FXUS64 KEWX 191955
AFDEWX
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
255 PM CDT Mon May 19 2025
...New SHORT TERM, LONG TERM...
.SHORT TERM...
(Tonight through Tuesday night)
Issued at 254 PM CDT Mon May 19 2025
Key Message:
- Low chances for isolated thunderstorms late this afternoon and evening
across the northern Hill Country and portions of the nearby I-35
corridor.
Dryline advancement is likely to be slower than previously
anticipated and this along with the stronger forcing to our north
may limit our convection chances for the remainder of this afternoon
and evening. However, any storms that manage to develop will likely
be severe with large hail and damaging winds being the main severe
weather concerns. The dryline will eventually advance eastward early
Tuesday morning as a cold front quickly follows behind. We have kept
rain chances out of the forecast Tuesday morning mainly for areas
east of the I-35/I-37 corridors as most of the hi-res models do not
show much of a signal for convection. We will continue to monitor
and may need to add some low rain chances pending model trends.
While we will see some very slight cooling across portions of the
southern Edwards Plateau, Hill Country into the nearby I-35
corridor, highs will still be well above normal ranging from the
lower to mid 90s. It will be hot again elsewhere as compressional
warming and downslope flow aid in yielding highs in the upper 90s to
near 105 degrees along the Rio Grande. Northerly winds, mostly clear
skies and dry air will allow low temperatures Tuesday night to drop
into the lower 60s to lower 70s.
&&
.LONG TERM...
(Wednesday through Monday)
Issued at 254 PM CDT Mon May 19 2025
Key Messages:
- Low to medium chances (20 to 40 percent) of isolated showers and storms
Thursday, Sunday, and Monday.
- Unseasonable warmth continues through the weekend with increasing humidity.
The slightly drier and cooler airmass in the wake of Tuesday`s cold
front will have only a brief stint over our region as redeveloping
zonal flow aloft quickly reestablishes a low-level southerly flow by
Wednesday evening, which holds for the remainder of the long term
forecast period. Temperatures look to be slightly moderated from the
mid May heat wave, but are still forecast to be well above normal
values for the time of year with highs in the 90s throughout South
Central Texas. Late Wednesday into Thursday, medium range guidance
depicts a shortwave tracking across Coahuila into South Texas. This
will favor convective development over higher terrain in Mexico, and
these could persist into the Rio Grande Plains late Wednesday into
early Thursday. Model soundings suggest capping could build in
quickly overnight, so rain and thunder chances would depend on the
timing of the shortwave... earlier onset of convective activity over
the high terrain would be more favorable for those chances, though
current placement of the disturbance would primarily limit coverage
to our southwestern counties. There remains large spread in
shortwave timing in the latest guidance, and PoPs remain limited to
the Rio Grande Plains with values less than 20 percent.
On Thursday, a slight southward push of high pressure rearward of an
outgoing longwave trough under northwesterly flow aloft may push a
backdoor cold front over North Texas. As the front encounters the
advancing moist Gulf airmass over our region, that could trigger
some storms, and storm motion vectors do favor southward progression
potentially into our area. While it is somewhat doubtful that the
front itself would reach this far south (as the GFS depicts),
isolated storms could move off ahead of the front and affect our
northern counties, with higher chances (with PoPs up to 30 percent)
over the northern Hill Country and northern I-35 corridor later in
the day. Some of the guidance suggests potential for a more
organized multi-storm cluster, but mesoscale factors are too
uncertain at this range.
Mid-level ridging becomes well established Friday and throughout
Memorial Day weekend. Ambient temperatures are forecast to remain
unseasonably warm, with highs in the upper 90s across most of the
region and low 100s along the Rio Grande. Gradually increasing
moisture thanks to the persistent southerly flow will drive heat
indices into the 100 to 105 range, with low temperatures creeping up
into the mid 70s over the weekend. An increase in troughing late
Sunday into early next week over the western CONUS will promote
increased divergence and a strengthening and thickening of the low-
level jet over our area. This supports a more stout near-surface
moist layer and chances for rain late Sunday into Monday across
South Central Texas. As the aforementioned troughing brings
southwesterly flow aloft into our area, the stage could be set for a
wetter and stormier pattern next week. The Climate Prediction Center
notes odds tilted towards above average precipitation for next week
throughout Texas.
&&
.AVIATION...
(12Z TAFS)
Issued at 624 AM CDT Mon May 19 2025
MVFR ceilings have overspread much of South Central Texas with VFR
conditions only in the far west including KDRT. Widely scattered
thunderstorms have formed over the Rio Grande Plains and are moving
northeast over the southern Edwards Plateau and Hill Country this
morning. Given their track, have no mention of precipitation at
terminals. Southerly wind will become gusty this morning through the
afternoon at I-35 sites before decreasing this evening. At KDRT,
wind becomes lighter this morning before becoming westerly behind the
dryline. Isolated thunderstorms may develop again this afternoon or
evening mainly over the Hill Country or northern I-35 corridor,
however confidence remains low enough to not mention in the AUS TAF
at this time.
&&
.CLIMATE...
Issued at 227 PM CDT Sun May 18 2025
RECORD MAX TEMPERATURES MONDAY AND TUESDAY
(* TIED RECORD WITH MOST RECENT OCCURRENCE SHOWN)
MON TUE
05/19 05/20
-----------------------------
AUS 97/2006 99/2008
ATT 98/2022* 101/2008
SAT 101/1989 100/1996
DRT 108/2020 105/1973
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 95 73 96 66 / 20 10 0 0
Austin Bergstrom Intl Airport 95 73 97 63 / 20 10 0 0
New Braunfels Muni Airport 97 73 99 66 / 10 10 0 0
Burnet Muni Airport 93 68 92 63 / 40 20 0 0
Del Rio Intl Airport 104 71 100 72 / 20 0 0 0
Georgetown Muni Airport 93 70 92 61 / 20 20 0 0
Hondo Muni Airport 99 70 100 69 / 20 0 0 0
San Marcos Muni Airport 96 73 99 64 / 20 10 0 0
La Grange - Fayette Regional 93 76 97 66 / 10 10 0 0
San Antonio Intl Airport 98 74 100 69 / 10 10 0 0
Stinson Muni Airport 100 75 102 70 / 10 10 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...Platt
Long-Term...Tran
Aviation...Platt
No recent Short Term Forecast (NOW) has been issued for NWS Austin/San Antonio CWA (EWX).
Special Weather Statement Issued: 05/19/2025 06:28:00 PM UTC
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