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

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FXUS64 KEWX 250544
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1244 AM CDT Thu May 25 2017

.AVIATION...
VRBL winds 6 KTs or less overnight, however, some higher elevations
will have S winds 6 to 12 KTs with some influence of 25 to 35 KT low
level jet. With heating on Thursday, low level jet mixes out leading
to S to SE winds 10 to 20 KTs with gusts up to 30 KTs. Decoupling
Thursday night decreases winds to 7 to 14 KTs. VFR skies prevail
overnight through Thursday evening. Lower level moisture returns
leading to MVFR CIGs late Thursday evening into overnight. Lower
level flow should be strong to enough to keep CIGs MVFR, however,
patchy or brief IFR CIGs are possible.

&&

.PREV DISCUSSION... /ISSUED 239 PM CDT Wed May 24 2017/

SHORT TERM (Tonight through Thursday Night)...
Upper air analysis this morning showed a deep trough over the middle
of the country with the trough axis across East Texas. The upper
level flow was from the northwest. At the surface, high pressure was
building in behind a cold front and winds across our CWA were from
the west-northwest. Dewpoint temperatures were 15 to 20 degrees lower
than 24 hours ago. The upper level trough will move off to the east
and be replaced by a a low amplitude ridge during this period and the
flow will shift to west-southwesterly. The surface high will move off
the coast tonight and winds will turn to the south to southeast
Thursday. After a cool start Thursday morning the period will be dry
with warming temperatures.

LONG TERM (Friday through Wednesday)...
The upper level ridge will slowly erode Friday and Saturday with the
flow becoming zonal by Sunday. Friday and Saturday will continue dry
with warming temperatures. Increasing temperatures and humidity will
drive heat indices above 100 over most of the area south of I-35/Hwy
90 and above 105 across the southwestern counties Friday and Saturday
afternoons for a few hours. A frontal boundary will move down from
the northwest reaching our northern border by Sunday morning and
pushing through our CWA by Monday morning. Showers and thunderstorms
will develop ahead of the front and continue as it moves through. The
GFS and ECMWF are showing differences in timing and rainfall amount
with the GFS producing higher amounts. Still both models are showing
what could be a significant event, but the differences have our
confidence low. The front will stall somewhere over South Texas and
then a series of upper level short wave troughs will move through the
pattern keeping chances for showers and thunderstorms in the
forecast through the end of the period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              74  94  77  95  76 /   0  -   10  10  10
Austin Bergstrom Intl Airport  73  93  76  95  75 /  -   -   10  10  10
New Braunfels Muni Airport     73  93  76  95  76 /  10  -   10   0  10
Burnet Muni Airport            72  93  75  94  73 /   0   0  10  -   20
Del Rio Intl Airport           75  95  77  97  77 /   0   0  -   -   20
Georgetown Muni Airport        74  93  76  94  74 /   0   0  10  -   20
Hondo Muni Airport             74  95  76  97  76 /   0  10  -   10  10
San Marcos Muni Airport        74  93  77  95  76 /  -   10  10  10  10
La Grange - Fayette Regional   74  92  77  95  77 /  -   10  10  -   10
San Antonio Intl Airport       75  94  77  96  76 /  -   10  10   0  10
Stinson Muni Airport           74  95  77  97  77 /  -   -   10   0  10

&&

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

$$

Mesoscale/Aviation...04
Synoptic/Grids...LH



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