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000
FXUS64 KEWX 161753
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1253 PM CDT Thu Aug 16 2018

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

&&

.AVIATION...
Currently VFR across the region under a scattered cumulus field.
Southerly winds have begun to increase at AUS and SAT with gusts up
to 20 to 25 knots possible through the afternoon hours (gusty winds
at SAT are expected to continue through the evening hours before
relaxing by around midnight). A bit of a tricky CIG forecast for
Friday morning. Most guidance is suggesting VFR CIGs to persist, but
meteorological conditions Friday morning will pretty closely
resemble those of this morning (in which MVFR CIGs did occur). The
best chances for MVFR CIGs will be at SAT/SSF, which should begin by
around 10z Friday morning before improving to VFR by late morning. I
keep AUS and DRT at VFR, but there is a chance for MVFR CIGs at these
locations as well, so have SCT at 1500 feet Friday morning to
account for this. South/southeasterly winds will persist through the
TAF period, with winds on Friday afternoon expected to be calmer than
those of today.

&&

PREV DISCUSSION... /ISSUED 411 AM CDT Thu Aug 16 2018/

SHORT TERM (Today through Friday)...
Subtropical Ridge slowly builds over our area. An upper level trough
moving from the northern Plains to the upper Mississippi Valley
weakens the surface pressure gradient slightly. This may allow for
increased speed convergence along the seabreeze and combined with
moisture convergence of slightly above normal PWS could generate very
isolated showers near the Coastal Plains as indicated by some of the
convective models. However, subsidence and warm temperatures aloft
should inhibit convective development and have kept POPs out of the
forecast. Cannot rule out a shower or two though. Due to continued
weaker surface pressure gradient, speed convergence is expected along
the seabreeze Friday. However, winds just above the surface turn
more from northeastern Mexico rather than the Gulf of Mexico leading
to a slightly drier airmass. Combined with increased subsidence and
warmer temperatures aloft keeps even very isolated showers from
developing and POPs remain out of the forecast. Slightly above normal
high temperatures are expected most areas, except near normal out
west where soils are still feeling the effects of the rains of a few
days ago. Slightly elevated heat index values are expected during the
afternoon hours.

LONG TERM (Friday Night through Wednesday)...
The Subtropical Ridge remains over our area this weekend maintaining
slightly above normal high temperatures, elevated afternoon heat
index values, and no POPS in the forecast. An upper level trough
currently off the West Coast moves onshore late Friday, then rides
over the top of the Ridge into the Plains this weekend. This causes
the Ridge to erode to the west with a northerly flow aloft forcing a
weak cold front into Central Texas early next week. Showers and
thunderstorms along the front could bring outflows into our area.
However, with enough of the Ridge overhead, expect only isolated
development in our area. The most recent ECMWF now brings another
front into our area during the middle of next week along with a
possibility of isolated showers and thunderstorms. For now, will keep
POPs out of the forecast until a better consensus shows in the
models. High temperatures fall closer to normal for early to middle
of next week due to at least the thicker mid and upper level clouds.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              77 101  77 101  77 /   0   0   0   0   0
Austin Bergstrom Intl Airport  76  99  76  99  76 /   0   0   0   0   0
New Braunfels Muni Airport     75  99  75 100  75 /   0   0   0   0   0
Burnet Muni Airport            74  98  74  97  75 /   0   0   0   0   0
Del Rio Intl Airport           77  99  78  99  77 /   0   0   0   0   0
Georgetown Muni Airport        76 100  77  99  76 /   0   0   0   0   0
Hondo Muni Airport             75 100  74 100  74 /   0   0   0   0   0
San Marcos Muni Airport        76  99  76 101  76 /   0   0   0   0   0
La Grange - Fayette Regional   77  98  77  98  78 /   0  -    0  -   -
San Antonio Intl Airport       77  98  77  98  77 /   0   0   0   0   0
Stinson Muni Airport           76 101  76 101  77 /   0   0   0   0   0

&&

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

$$

Mesoscale/Aviation...BMW
Synoptic/Grids...Platt
Public Service/Data Collection...YB