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

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FXUS64 KEWX 181144
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
644 AM CDT Fri Jun 18 2021

.UPDATE...
Please see the 12Z aviation forecast discussion below.

&&

.AVIATION...
VFR conditions are in store at area TAF sites through the current
forecast period. A few afternoon showers can`t be ruled out across
the Hill Country today. However, given low confidence and isolated
coverage, we will not include a mention in the I-35 sites today.
Otherwise, winds trend to a more easterly direction this afternoon
along I-35, with southeast winds expected at DRT.

&&

.PREV DISCUSSION... /ISSUED 327 AM CDT Fri Jun 18 2021/

SHORT TERM (Today through Saturday)...

On average, temperatures will continue to remain a few degrees above
normal today and again on Saturday. Highs will range from near 100
along the Rio Grande to the lower 90s in the Hill Country. Most
areas will remain dry today, except for possibly a few locations
across portions of the Hill Country. Daytime heating along with the
presence of a 700-500 Theta-E ridge axis could help initiate a few
afternoon showers across the mentioned area. With only isolated
convection expected, we will keep rain chances at 20%.

Mild overnight lows are in store, with temperatures forecast to
range from the upper 60s to the mid 70s. High temperatures on
Saturday could be a degree or two warmer than today`s forecast highs
as the low-level thermal ridge to our west strengthens. We should
see another round of highs in the lower 90s to lower 100s. Most
areas should also remain dry on Saturday. The exception will be
across the coastal plains where daytime heating and the sea breeze
could result in the development of isolated showers and
thunderstorms during the afternoon hours.

LONG TERM (Saturday Night through Thursday)...

Saturday evening, the upper level pattern will consist of a ridge
over the desert SW while a decaying tropical system will be located
over the southeastern US. Locally, there may be some weak upper
level troughing, with surface flow remaining out of the S/SE which
will keep the flow of moist gulf air in place, especially as we head
into Monday. There is a very low chance for a tropical shower or
thundershower to impact our far eastern counties Sunday afternoon,
otherwise expect a hot and humid day with highs in the 90s and lower
100s.

We`ll be even warmer on Monday, with model consensus suggesting
highs in the mid to upper 90s east and mid 100s west/southwest. Dew
points are also likely to remain in the 70s for all but far NW
portions of the region through the afternoon. As a result, heat
indices are forecast to exceed Heat Advisory thresholds across most
of the area save portions of the Hill Country. There is a chance
that clouds over the I-35 corridor hold on long enough into midday
that temperatures could be held closer to the 92-96 degree range
which could prevent the need for heat headlines over some of the
area, but details will be refined through the weekend.

A cold front does appear likely to enter the area from the north
Monday evening into Monday night as a trough digs through the Great
Lakes and high pressure builds in behind it. A few prefrontal
showers will be possible Monday over our far eastern counties, then
more widespread rain chances will fill in behind the front off and
on Tuesday, and low POPs may stick around as late as Wednesday
evening for some locations. Despite the deterministic global models
quickly shutting off precipitation late Tuesday, enough of the
ensemble guidance keeps some isentropic lift across primarily
eastern and southern portions of the region to warrant the lingering
low POPs. Overall, not a lot of precipitation is expected with a few
spots seeing 0.5-1" and some locations likely seeing little to no
precipitation at all. One or two ensemble members indicate a worst
case isolated 2-3" for some portion of the area, but not enough to
lead to any significant impacts.

Behind the front, cooler temperatures on Tuesday could allow for a
more comfortable day with highs in the mid-upper 80s for some folks
(still 90s west and south). But upper ridging and southeasterly low
level flow will return in earnest Wednesday and the warm, sticky
June weather will make a swift return as we head into the end of the
work week.

PREV DISCUSSION... /ISSUED 1242 AM CDT Fri Jun 18 2021/

UPDATE...
Please see the 06Z aviation forecast discussion below.

AVIATION...
VFR conditions are in store at area TAF sites through the current
forecast period. Light southerly or light and variable winds will
continue along the I-35 corridor through the morning hours. Winds
will then shift to a more easterly direction in the afternoon. At
DRT, east winds will continue through the morning, with southeast in
the afternoon. Skies will remain VFR through the period with FEW-SCT
clouds in the 6-7k AGL range.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              96  70  97  74  96 /   0   0  -   -   -
Austin Bergstrom Intl Airport  94  68  95  73  95 /   0   0  -   -   -
New Braunfels Muni Airport     96  69  96  74  97 /   0   0  -    0  -
Burnet Muni Airport            94  69  95  72  96 /  20  20  -    0   0
Del Rio Intl Airport          101  75 102  77 103 /   0   0   0   0   0
Georgetown Muni Airport        94  69  94  73  95 /  -    0  -   -   -
Hondo Muni Airport             94  69  96  73  97 /   0   0   0   0  -
San Marcos Muni Airport        95  69  95  73  96 /   0   0  -   -   -
La Grange - Fayette Regional   95  72  96  77  95 /   0   0  10  -   10
San Antonio Intl Airport       94  71  96  75  96 /  -   -   -    0  -
Stinson Muni Airport           96  72  97  76  98 /  -   -   -    0  -

&&

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

$$

Short-Term/Aviation...Platt
Long-Term...KCW


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