Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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FXUS64 KEWX 070829
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
329 AM CDT Sun Jun 7 2020

.SHORT TERM (Today through Monday Night)...
Pronounced subtropical ridge in place over the central CONUS will
keep our weather pattern warm and benign. A weakness in the ridge,
also known as Tropical Storm Cristobal, will make landfall over
eastern Louisiana late today. Upper level trough currently located
over the pacific northwest will begin to progress eastward across
the central plains early Monday and usher the remnants of Cristobal
northeastward over the Mississippi River Valley, approaching the
midwest by the end of the short term period.

Dry weather and heat will be the main story for south-central Texas.
Given the displacement from Cristobal, the only impact felt for the
region will be northeasterly flow at the surface and the additional
subsidence will only help to raise temperatures. Seeing any far
reaching bands of precip from Cristobal seems very unlikely and have
left any mention of it out of the forecast.

Models have trended slightly cooler for today`s highs with the
anticipated northeasterly flow, but it will still be a hot one with
highs running about 5 degrees above average for early June.
Temperatures will really begin to climb on Monday with afternoon
highs reaching 100 along the I-35 corridor and 105 out along the Rio
Grande.

&&

.LONG TERM (Tuesday through Saturday)...
The main highlights of the long term will all occur Tuesday and
Tuesday night. The Wednesday through Saturday time frame will be
characterized by hot and dry weather. The upper level ridge will be
draped across the Southern US with the surface high pressure sitting
over the Ozarks. Light easterly winds, mostly sunny afternoons, with
highs in the mid 90s will be the forecast on repeat for the second
half of the work week into the weekend.

The first of the two highlights will be the heat on Tuesday. Models
have trended slightly "cooler" with forecast highs on Tuesday with
I-35 temperatures 101-103 and 105-108 along the Rio Grande Plains.
This will still bring record breaking heat to some of our climate
sites. Check out the table below for details on records for Monday
and Tuesday. The heat will be caused by a combination of factors.
Subsidence from the departing remnants of Tropical Storm Cristobal
will combine with compressional warming ahead of an approaching cold
front. Both of these features work to compact the air and when air
is compacted, its temperature inherently rises. The probable reason
for models backing off slightly on the oppressive heat is it looks
like these features will be less in sync then previously forecast,
with less subsidence from Cristobal and also possibly a later front
arrival delaying the compressional warming. Because of the tropical
airmass in place heat index values on Tuesday afternoon will reach
from 103 to 111 across the area. Based on the forecast highs and heat
index values a heat advisory will probably be needed for Tuesday.

The second of the two highlights will be a cold front expected to
move through the area Tuesday afternoon into Tuesday night. This
front is associated with the upper trough which will be moving across
the Central Plains Tuesday and Wednesday. The global models are in
good agreement that the front will arrive across the Hill Country and
Edwards Plateau Tuesday afternoon and then slowly move through during
the evening and early overnight hours. Ahead of the front there
should be a decent amount of instability. Global models have shown a
thin line of precipitation along the front as it moves along and east
of the I-35 corridor into the Coastal Plains for the last few cycles.
With the National Blend of Models now picking up on this
precipitation have introduced 20 PoPs into the forecast for Tuesday
night. With the decent amount of instability in place an isolated
thunderstorm could produce some marginally severe hail and/or
damaging wind gusts. While surface moisture will be pooled ahead of
the front and lift/convergence along the front should be sufficient
enough to spark off at least isolated precipitation there are also a
few limiting factors. Model soundings show at least a modest capping
inversion in place, but the bigger limiting factor may be a growing
dry layer around 850mb and more drying aloft. Models show the front
hanging up along the Texas Coast late Tuesday night into Wednesday,
but the focus of the precipitation should be south of the area. The
front will act to "cool" South Central Texas down 10 degrees from
around 103 to the low to mid 90s on Wednesday.

&&

.CLIMATE...

Record High Temperatures:
Record High (Year of Record) [2020 Forecast High]

                       Mon Jun 8         Tues Jun 9
Austin Bergstrom    99 (1956) [100]   99  (1948) [102]
Austin Camp Mabry  102 (1925) [100]   101 (2008) [103]
San Antonio        101 (1948) [101]   104 (1910) [103]
Del Rio            104 (1953) [106]   112 (1988) [106]


&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              96  76 100  78 103 /   0   0   0   0   0
Austin Bergstrom Intl Airport  96  75 100  76 102 /   0   0   0   0   0
New Braunfels Muni Airport     95  74 101  76 102 /   0   0   0   0   0
Burnet Muni Airport            93  72  98  76 101 /   0   0   0   0   0
Del Rio Intl Airport          101  76 107  78 107 /   0   0   0   0   0
Georgetown Muni Airport        96  73 100  77 103 /   0   0   0   0   0
Hondo Muni Airport             98  73 104  75 105 /   0   0   0   0   0
San Marcos Muni Airport        96  73 101  76 103 /   0   0   0   0   0
La Grange - Fayette Regional   96  74  99  78 101 /   0   0  -    0   0
San Antonio Intl Airport       96  76 101  77 103 /   0   0   0   0   0
Stinson Muni Airport           96  76 101  77 103 /   0   0   0   0   0

&&

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

$$

Short-Term/Aviation...EWilliams
Long-Term...Treadway



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