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

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955
FXUS64 KEWX 280046
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
746 PM CDT Mon Mar 27 2017

.AVIATION.../00Z TAF CYCLE/

VFR conditions prevail across the region with very isolated TSRA
across the Hill Country. This activity will dissipate by 130-02Z.
MVFR ceilings will return to KAUS/KSAT/KSSF near 03-04Z and then fall
to IFR 07-08Z. Ceilings could approach LIFR at times but confidence
in temporal occurrence is low to not include on this issuance. KDRT
will follow suit but be delayed by 3 hours or so behind the other
sites. Ceilings will improve through mid to late morning hours to
MVFR then VFR by the early afternoon for all locations. Surface
winds will be southeast and then south through the overnight into
Tuesday with some gusts reaching into the 20-25 knot range ahead of
strong storm system. Increased SHRA and TSRA activity is expected
late Tuesday night into Wednesday morning across south-central
Texas. TSRA will likely be added to TAFS in the next few cycles when
timing can be better assessed.

&&

.PREV DISCUSSION... /ISSUED 349 PM CDT Mon Mar 27 2017/

SHORT TERM (Tonight through Tuesday Night)...
The main concern in the near term will be monitoring a retreating
frontal boundary for possible convection this afternoon and evening.
Chances are fairly low, but we have included a slight chance for
areas along and north of a Lexington to Burnet to Fredericksburg
line. Any convection that develops is expected to decrease with the
loss of daytime heating. For the overnight hours, south to
southeasterly flow in the low-levels will increase, bringing an
increase in moisture to all areas. Some models show some light
showers developing overnight across the coastal plains and Hill
Country areas. We will leave this out of the forecast for now as
overall confidence is low. Attention will then turn to an upper level
trough set to impact the region beginning Tuesday afternoon. Several
hi-res models show potential for convection to break out during the
late afternoon hours across the Rio Grande plains, southern Edwards
Plateau and Hill Country. If convection does manage to develop,
storms would likely become severe fairly quickly given good CAPE
values along with adequate vertical wind shear. By early evening,
the dryline located across west central Texas is expected to become
increasingly active. As dryline storms propagate eastward,
thunderstorm chances will be on the increase for areas along and west
of I-35 during the overnight hours. Some of the hi-res models show
the line of storms could weaken as they approach the I-35 corridor.
I`m not completely sold on this solution as we should still have some
good lift across the region with the upper low to our west.

LONG TERM (Wednesday through Monday)...
Early Wednesday morning, we expect showers and thunderstorms to be
ongoing across much of the Hill Country and I-35 corridor. For the
afternoon hours, convection should move east of the I-35 corridor as
the cold front shifts east. We will need to monitor the front during
the afternoon hours on Wednesday as this may provide a focus for
convection. The upper level trough axis moves east of our region
Thursday afternoon as dry, northwest winds spread over the area. Dry
weather continues on Friday, but southerly winds will quickly return
to the area ahead of the next upper level system. There is some
disagreement among the extended models with regards to the timing of
the next upper trough. The ECMWF remains faster and shows a more open
wave, while the GFS and Canadian show more of a closed upper low. We
will continue to monitor and for now will show rain chances for most
areas Saturday through Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              68  86  67  84  57 /  10  30  70  50  10
Austin Bergstrom Intl Airport  68  86  67  83  55 /  10  20  70  60  10
New Braunfels Muni Airport     67  85  67  85  56 /  10  20  70  50  10
Burnet Muni Airport            65  80  62  81  53 /  20  30  80  30  10
Del Rio Intl Airport           69  87  60  87  56 /  -   30  60  10   0
Georgetown Muni Airport        65  84  65  82  55 /  20  30  70  50  10
Hondo Muni Airport             68  84  64  87  55 /  10  30  70  20  10
San Marcos Muni Airport        68  85  68  84  54 /  10  20  70  60  10
La Grange - Fayette Regional   68  86  71  80  59 /  10  10  50  80  20
San Antonio Intl Airport       69  83  67  86  57 /  10  30  70  40  10
Stinson Muni Airport           69  85  67  85  57 /  10  20  70  40  10

&&

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

$$

Mesoscale/Aviation...Allen
Synoptic/Grids...17
Public Service/Data Collection...Williams



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