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

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FXUS64 KEWX 211855

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
155 PM CDT Thu Sep 21 2023


(Tonight through Friday night)
Issued at 154 PM CDT Thu Sep 21 2023

The sub-tropical ridge has built back over the south central part of
the country with its center over the southern tip of Texas. The flow
over the state is turning anticyclonically from west-southwest to
northwest. The low level flow is from the southeast maintaining a
warm, moist airmass over South Central Texas. Dewpoints have
increased around five degrees over the last 24 hours. Cloudiness
this morning has temperatures a little lower than yesterday, but we
expect that deficit to be made up quickly as the skies clear.

South Central Texas will remain under the influence of the upper
level ridge through the short term. Temperatures will continue to be
warm. Continued low level flow from  the Gulf will bring a surge of
deeper moisture tonight and Friday. Precipitable water values will
increase to around 1.5-2.0 inches over the Hill Country, I-35
corridor, and Coastal Plains during the day on Friday. This could
lead to isolated showers Friday. Dry weather will return Friday

High temperatures Friday will continue to be warm, in the mid 90s
across the Hill Country, upper 90s to isolated spots near 100 along
the I-35 corridor and inland Coastal Plains, and 100 to 102 along
the Rio Grande. Peak afternoon heat index values also are on the
increase and a few spots in the Coastal Plains could reach heat
advisory criteria briefly during the afternoon. Morning lows Friday
and Saturday will be well above normal mostly in the middle to upper


(Saturday through Thursday)
Issued at 154 PM CDT Thu Sep 21 2023

Ridging remains in place this weekend, with hot temperatures for
late September. Highs in the mid 90s to low 100s are forecast for
most areas, with lows in the 70s. Saturday evening, a boundary to
our NW will set off a few showers and storms that could impact
northern Val Verde/Edwards Counties, but this is a low chance capped
at 15%.

Late on Sunday, a cold front will begin to push south through TX,
but will likely not reach our area. However, some shortwave energy
aloft and potential boundaries left over from previous convection
should allow for isolated to widely scattered showers and storms to
impact mainly northern portions of the region late in the day. These
chances will continue overnight, focusing on mainly northeastern
areas after midnight. Expecting to see a lull in activity Monday
morning for most of the region, though there will remain a chance
over mainly eastern areas. Slightly cooler temperatures
topping out mainly in the 90s are forecast during the day.

Another round of showers and storms - likely the most widespread of
the week - is forecast Monday afternoon into Monday night. This
round will bring the highest potential for localized 1-3" rainfall
amounts, and a Marginal Risk of Excessive Rainfall will be in place
across much of the region, except along the Rio Grande. However,
ensemble probabilities of QPF>0.5" during this period are only 10-
40%, highest east of Austin, so as usual it`s likely many areas miss
out on appreciable rainfall totals. Can`t rule out isolated strong to
severe storms either, but too soon to go into much detail there.

Temperatures will be cooler still on Tuesday, topping out in the 80s
north and low 90s south, close to but still mainly above seasonal
norms. Can`t rule out some isolated lingering showers, but most of
the rain is likely to be done for the week by this time with
subtropical ridging attempting to re-establish itself. We`ll start
another slight warming trend through the middle of next week, with
above normal temperatures likely to continue into the beginning of


(18Z TAFS)
Issued at 1237 PM CDT Thu Sep 21 2023

This morning`s low ceilings have lifted and/or dissipated and all
airports will be VFR through the afternoon and evening. Winds could
get gusty this evening, especially in the San Antonio area. Moist,
southeasterly flow will continue and MVFR ceilings will redevelop
overnight in the Austin and San Antonio areas. Low ceilings will last
until late morning Friday.


Issued at 630 AM CDT Thu Sep 21 2023

Record High Temperatures:

         9/21         9/22
AUS - 102F (2005)  103F (2005)
ATT - 100F (1926)  102F (1926)
SAT - 100F (1909)  101F (1926)
DRT - 101F (1992)  102F (1946)

      Temp (Year)


Austin Camp Mabry              74  99  76  98 /  10  20   0  10
Austin Bergstrom Intl Airport  74  98  76  98 /  10  20   0  10
New Braunfels Muni Airport     75 100  77  99 /  10  20   0  10
Burnet Muni Airport            74  95  76  96 /  10  10   0   0
Del Rio Intl Airport           76 101  78 102 /   0  10   0   0
Georgetown Muni Airport        74  96  76  97 /  10  20   0   0
Hondo Muni Airport             73  98  74  99 /  10  10   0   0
San Marcos Muni Airport        73  98  74  98 /  10  20   0  10
La Grange - Fayette Regional   75  96  75  97 /   0  30   0  20
San Antonio Intl Airport       76  99  77  99 /  10  20   0   0
Stinson Muni Airport           77 100  78 101 /  10  20   0   0




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