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

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FXUS64 KEWX 251753
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1153 AM CST Sat Jan 25 2020

.UPDATE...
See below for the 18z aviation discussion...

&&

.AVIATION...
Cloud cover is increasing from west to east as a shortwave trough
approaches the region. DRT is already MVFR, with AUS/SAT/SSF expected
to follow suit later this afternoon. With isentropic ascent
increasing later this evening, CIGs are expected to further
deteriorate to IFR and eventually LIFR early Sunday morning. Fog and
drizzle are also expected to develop, with dense fog possible,
especially at SAT. At this time, any heavier precipitation should
stay east of AUS/SAT/SSF, so have continued to keep out any
prevailing rain for this TAF issuance. Conditions are expected to
improve to VFR by late Sunday morning as the trough axis and weak
cold front move through, bringing drier air to the region in its
wake. Winds this afternoon will be south southeasterly around 10
knots (higher at AUS) before becoming light and variable tonight.
Northwesterly winds will arrive behind the front by late Sunday
morning and should generally remain below 10 knots.

&&

PREV DISCUSSION... /ISSUED 300 AM CST Sat Jan 25 2020/

SHORT TERM (Today through Sunday)...
A southern stream shortwave aloft moving through Mexico this morning
will arrive into portions of South Texas this afternoon and tonight,
and link up with a northern stream shortwave trough late tonight
into Sunday morning. Cloud cover ahead of the feature will gradually
increase through the day. By this afternoon the moisture depth below
700mb, combined with weak forcing with the approach of the
shortwave, may allow for a few showers to develop across southern
areas of the CWA.

Isentropic ascent is forecast to steadily increase late this
evening, leading to lowering cloud bases and areas of drizzle and
fog developing through central and eastern areas of the CWA, in
addition to a chance of showers. The fog may expand into western
areas of the CWA overnight. Can`t rule out some areas of dense fog
developing overnight across the CWA.

As the trough passes east early Sunday morning low level flow will
veer west to northwest, allowing isentropic downglide to develop
and drier air to filter into the region. This should result in
clearing from northwest to southeast Sunday morning into early
afternoon. Despite the weak cold front passage, temperatures on
Sunday will be warmer than today. Highs today are forecast to be in
the 60s and on Sunday in the low to mid 70s.

LONG TERM (Sunday Night through Friday)...
With northerly winds and drier air settling in behind the front,
overnight lows dip back into the 40s. Monday will warm again with
highs in the low to mid 70s, still a good 10 degrees higher than
normal. Winds return out of the southeast on Monday and moistening
begins ahead of the next disturbance. As an upper trough moves
across North Texas, dragging another weak cold front with it, shower
and some isolated thunder across the area can be expected Tues. The
front passes through Tuesday morning into the afternoon. Gusty
northwest winds follow behind the front and drier air filters in from
west to east, clearing skies by Tuesday evening. High temperatures
for Wednesday drop down closer to normal from the low to mid 60s. The
next approaching system progged for late next week could bring more
rain for Thursday and Friday. Inconsistent model runs paint very
different pictures for the progression of this disturbance. With low
confidence, kept a modest blend for late next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              65  55  73  45  71 /  -   30   0   0   0
Austin Bergstrom Intl Airport  66  54  73  44  72 /  -   40   0   0   0
New Braunfels Muni Airport     66  55  74  45  72 /  10  50   0   0   0
Burnet Muni Airport            64  51  70  42  70 /  -   10   0   0   0
Del Rio Intl Airport           64  53  76  47  77 /  -    0   0   0   0
Georgetown Muni Airport        65  53  71  43  69 /  -   30   0   0   0
Hondo Muni Airport             66  54  76  45  76 /  10  20   0   0   0
San Marcos Muni Airport        67  55  73  44  72 /  -   50   0   0   0
La Grange - Fayette Regional   69  58  73  46  72 /  10  60  20   0   0
San Antonio Intl Airport       66  56  75  47  73 /  10  50   0   0   0
Stinson Muni Airport           66  57  76  48  74 /  20  50   0   0   0

&&

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

$$

Short-Term/Aviation...BMW
Long-Term...17
Decision Support...KCW


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