306
FXUS64 KEWX 031109
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
609 AM CDT Mon Jun 3 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday)
Issued at 245 AM CDT Mon Jun 3 2024

Increasingly dangerous heat is now becoming the primary weather
story within the short term but there will still remain a lingering
low end chance (20%) for convection later this afternoon and into
this evening across the region. The HREF CAM members are generally
indicating two possible areas for activity. The first area is across
the Rio Grande Plains down into the CRP CWA while the second would
focus from mainly the Hill Country northward into Central Texas
across the SJT/FWD CWAs. Several of the members do indicate that a
convective complex could evolve across the FWD CWA. If this does
evolve, it could help advance outflow southward into the region
after dark and may act as a catalyst itself for a few showers or a
storm or two as well. Instability and shear is enough across the
region to where a strong to severe storm may be possible. If a
strong to severe storm is able to develop, damaging winds and large
hail would be the primary hazards. Most locations will not receive
rain or storms and should remain under partly to mostly cloudy sky.
Latest model guidance continues to favor an even drier forecast on
Tuesday where rain chances trend around or below 10 percent area
wide.

Now let`s return to that heat. Afternoon highs will be expected to
climb into the mid to upper 90s across most locations while areas
along and near the Rio Grande peak at or above 100 degrees. With
elevated dew points in the upper 60s to the mid 70s persisting
through the afternoon, heat indices are expected to reach up into
the 104 to 112 degree range this afternoon across most locations
outside from the Hill Country. Highest heat indices concentrate
across the Rio Grande Plains, which has prompted a Heat Advisory
across those locations from 1 PM through 7 PM CDT. From Val Verde
county into the I-35 corridor and the coastal plains, a Special
Weather Statement was issued through 7 PM CDT as result of these
heat indices today. Tuesday looks to trend slightly hotter across
the region where ambient temperatures trend up to a few degrees
warmer than this afternoon. This likely will lead to an areal
expansion of the Heat Advisory for Tuesday as most locations will
see heat indices peak slightly higher in comparison of today`s
forecast heat indices. Those spending an extended amount of time
outdoors and not acclimated to the heat are susceptible to heat
related illness, if not taking the proper heat precautions.

Heat Precautions: Never leave people and/or pets alone within a
closed car, stay hydrated with plenty of water, wear loose-fitting
and light colored clothing, and take frequent breaks within the
shade and air conditioning.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 245 AM CDT Mon Jun 3 2024

Mid level ridging shifts toward our area on Wednesday, then centers
nearby Thursday into Friday. All models indicate hotter conditions
for this time frame. However, there remains some uncertainty on
exactly how hot and how much the dewpoints mix with heating.
Regarding the models, the GFS is the hottest and driest while the
ECMWF and CMC are less hot and more moist. Regarding the ambient
conditions, recent rains have saturated the soils mainly across the
Hill Country to along and east of I-35 where amounts greater than 1
inch have occurred. It will take time to dry these soils keeping
dewpoints elevated in those areas due to inefficient
evapotranspiration. Meanwhile, across the Rio Grande Plains and
Winter Garden areas, rainfall has been much less, averaging less
than 1/10 inch. It must be noted that there were heavier rains up to
2 inches across portions of the Winter Garden and nearby Rio Grande a
few days ago, however their impact is much less now with a few days
of drying there. Thus, with drier soils, dewpoints should mix more
efficiently and in turn causing the hottest temperatures there. Have
gone with dewpoints lower than NBM across those areas. Taking all
this into account, parts of our area will likely reach Heat Advisory
levels on Wednesday, and possibly Thursday, especially areas where
the dewpoints are slower to mix. It also is possible to have a small
Excessive Heat Warning area on Wednesday. Subsidence underneath the
ridge should provide strong convective inhibition. However, cannot
rule out a strong thunderstorm or two where temperature/dewpoint
discontinuity sets up due to strong heating especially late Wednesday
afternoon into early evening due to the ridging not established yet.

The GFS maintains ridging, though slightly weaker, through next
weekend while the ECMWF and CMC move it away from our area. Expect
the afternoon heat to drop below Advisory levels. A drier airmass
will keep rain chances out of the forecast.

&&

.AVIATION...
(12Z TAFS)
Issued at 602 AM CDT Mon Jun 3 2024

MVFR ceilings generally persist this morning at the area TAF sites
before improving to VFR levels entering the afternoon. There remains
a low to very low opportunity for convection later this afternoon
into tonight but confidence is so low on if storms will develop and
placement of location to insert TSRA and VCTS within any of the
TAFs. MVFR ceilings return after midnight tonight and should
continue into Tuesday morning. A light to moderate east-southeast to
southeast flow will continue with gusts as high as 20 to 25 knots
trending late this afternoon through the evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              93  77  96  77 /  10  20  10  10
Austin Bergstrom Intl Airport  93  77  96  77 /  10  20  10  10
New Braunfels Muni Airport     96  77  98  77 /  10  10  10  10
Burnet Muni Airport            91  74  93  75 /  20  20  10  10
Del Rio Intl Airport          103  79 106  81 /  10  10   0   0
Georgetown Muni Airport        92  75  96  76 /  20  20  10  10
Hondo Muni Airport             97  77  99  76 /  10  10  10  10
San Marcos Muni Airport        94  77  97  76 /  10  10  10  10
La Grange - Fayette Regional   92  78  94  77 /  10  10  10  10
San Antonio Intl Airport       96  78  98  77 /  10  10  10  10
Stinson Muni Airport           98  78  99  78 /   0  10  10  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM this afternoon to 7 PM CDT this evening for
Atascosa-Dimmit-Frio-Maverick-Zavala.

&&

$$

Short-Term...Brady
Long-Term...04
Aviation...Brady