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

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FXUS64 KEWX 080529
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1229 AM CDT Sat May 8 2021

.AVIATION...
MVFR CIGs have moved over the I-35 sites and will spread to KDRT
early Saturday morning. South to southeast winds of 8 to 14 KTs will
keep CIGs MVFR, although may briefly dip to IFR around sunrise as
winds will be weakest then. As winds increase to 10 to 20 KTs with
gusts to 30 KTs during the morning due to mixing, CIGs will lift and
become SCT VFR by midday. MVFR CIGs return late Saturday evening at
the I-35 sites and KDRT late Saturday night.

&&

.PREV DISCUSSION... /ISSUED 320 PM CDT Fri May 7 2021/

SHORT TERM (Tonight through Saturday Night)...
A small amount of low level moisture returned this morning only to
see surface dew points quickly mix out with the drier air above the
boundary layer this afternoon. The moisture will return quickly for
this evening, and low cloudiness areas should pick up by around
midnight tonight. The upper ridge over TX will deflate quickly
tonight as a progressive subtropical pattern returns with a broad
upper trough that is part of a broader upper low digging into the Nrn
Rockies. This will increase surface winds and gusts, so little or no
fog is expected from the moisture return. A few pockets of drizzle or
light streamer showers may develop over parts of the Coastal Prairies
toward daybreak Saturday. More warm, breezy and humid conditions are
expected Saturday night.

LONG TERM (Sunday through Friday)...
The relatively low amplitude wave moving through the SWrn CONUS into
TX will push a dry-line east into Central TX while a weakening cold
front stalls over Central TX just north of the CWA late Sunday. There
is a chance that no precipitation makes it this far south but if an
outflow boundary reaches the area, the SPC has us in a Marginal Risk
area. Even the more bullish NAN model with regard to the front keeps
the stronger convection to the NE, so we`ll downplay the severe
threats that might threaten our CWA borders over the weekend. By
Monday, moisture really ramps up over the area and there could be a
tropical connection with a weak but developing tropical Pacific
disturbance. Pwat values approach 2 inches by 00Z Tuesday, leading to
a breakable cap across the CWA but probably mostly likely over the
weak frontal zone along our northern CWA border and over the Burro
Mountains in Mexico.

This destabilization out west may end up drawing the front south
across half the area Monday evening with a complex taking shape to
cover 2/3rds of the area Monday evening. Again a few severe storms
could be possible, but will leave the specifics vague for another
forecast package due to frontal location uncertainties. Certainly
there could be a region for locally heavy downpours up to 3 inches,
but will not speculate on where at this time. The front is by midday
Tuesday, forecast by the deterministic consensus to be stuck over
the area to bring a likely PoP category for Tuesday evening into
early Wednesday morning. By this time, a heavy rain event should have
happened, but the destabilizing trends for Monday may shade the
potential for the heaviest rains forward in time, should the front
maintain enough momentum from outflows to continue south.

By early Saturday morning, with the arrival of some more finer res
and regional models, we might be able to pinpoint timing and threat
regions for the period Monday evening through early Wednesday morning
for better messaging. Most models depict some weak stability behind
the front, so the forecast for late Wednesday into Thursday could
become more dry in terms of rain chances. The more confident aspect
of the extended forecast is that there is enough meridional flow in
the mid levels to keep a continental NE low level wind over the area
into Thursday which should bring another welcome period of mild
weather throughout the extended forecast, and slightly cooler than
usual for mid-May.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              71  91  72  86  65 /  -   20  10  30  60
Austin Bergstrom Intl Airport  71  91  71  86  65 /  -   20  10  30  50
New Braunfels Muni Airport     72  93  72  90  68 /  -   10  -   30  50
Burnet Muni Airport            69  88  67  80  62 /  10  20  10  40  50
Del Rio Intl Airport           72 101  71  96  70 /  -    0   0  20  30
Georgetown Muni Airport        70  90  70  83  63 /  10  20  20  40  60
Hondo Muni Airport             69  96  70  94  68 /  -   -   -   20  40
San Marcos Muni Airport        71  91  71  88  65 /  -   10  -   30  50
La Grange - Fayette Regional   73  88  73  88  69 /  -   20  10  30  50
San Antonio Intl Airport       71  93  72  91  68 /  -   10  -   30  50
Stinson Muni Airport           72  95  73  93  70 /  -   -   -   20  50

&&

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

$$

Short-Term/Aviation...04
Long-Term...Oaks


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