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

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969
FXUS64 KEWX 181524
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1024 AM CDT Fri Oct 18 2019

.UPDATE...
Quick update to account for temperature and sky cover trends across
the Rio Grade Plains where lingering cloud cover has slowed heating
this morning. Visible satellite trends show this deck eroding and
still expect a pleasant and mild day for the region with highs in the
low to mid 80s. Remainder of forecast is on track.

&&

.PREV DISCUSSION... /ISSUED 622 AM CDT Fri Oct 18 2019/

AVIATION...
Saw some brief VFR clouds at the San Antonio sites a couple of hours
ago but these have since dissipated. These low clouds are a precursor
to more widespread MVFR or IFR ceilings expected tomorrow morning at
the I35 sites. Otherwise, winds will be light through the period.

PREV DISCUSSION... /ISSUED 353 AM CDT Fri Oct 18 2019/

SHORT TERM (Today through Saturday)...
NE winds over the Coastal Prairies will limit warming slightly today
as the inversion left behind the compact departing upper low will not
fully mix out. Out west, areas along the Rio Grande should see highs
a few degrees warmer with better mixing from the westerlies above the
boundary layer. Tonight a fast moving shortwave trough moves into the
Red River valley and brings the return of southerly and boundary
layer winds across all areas. The surface pressure gradient is
expected to remain weak while higher surface dewpoints near the coast
surge northward into the Coastal Prairies. This could lead to some
low level saturation with patchy advection fog after midnight. A weak
Pacific style front arrives by the afternoon, and the mixing levels
and downsloping effects will translate to a more rapid warmup to near
attainable record highs for some locations.

LONG TERM (Saturday Night through Thursday)...
The Pacific front stalls late Saturday night over the Coastal
Prairies, and there should be a fair amount of moisture in the low
levels to generate some light radar echoes, whether it be light
sprinkles or drizzle. Progressive zonal flow aloft will enhance
return flow Sunday and the moisture surge will deepen quickly in the
low levels as a vigorous upper low digs into the Central and Northern
Plains by 00Z Monday. Low coverage and low confidence PoPs of mainly
showers are expected to be possible along and east of I-35 Sunday
afternoon, and high temps should again reach several degrees above
normals.

While the rapidly forming upper low well to the north of TX, the jet
stream wrapping south of it cuts into NW TX to OK, and develops a
rapidly sharpening cold front that is set to arrive late Sunday night
into Monday morning. The sharpening of the front occurs over NW TX
and a broken line of thunderstorms is expected to arrive into the
the Hill Country by late Sunday evening and into the SE corner of the
forecast area after daybreak Monday. Deterministic model depictions
are mostly in agreement, but the Nam appears to be coming in much
drier and a bit slower with the front. For this reason, will continue
to undercut likely PoPs to chance for all but the Coastal Prairies.
Late night timing usually limits the potential for severe weather,
but timing of activity in our northernmost counties late in the
evening could lead to a few strong storms.

Run to run trends on frontal strength look to be consistent over the
past several runs, with the front looking somewhat typical for mid
October. Seasonally mild and mostly clear weather is expected to last
into Wednesday night with clouds and humidity expected to return
Thursday morning. The warm and humid day Thursday should be short-
lived with another front arriving early Thursday evening. Run-to-run
tendencies might suggest this front may delay until later in the
night, but already the model agreement is above average on showing
another round of scattered convection with the front.

In the case of both fronts, there is a weak connection of mid-level
winds with an unstable Eastern Pacific Ocean. A change in this
tropical connection or a more mature development of a tropical
disturbance in this region could alter rain potential.

CLIMATE (Record Highs for Saturday Oct 19)...
AUS 93 (1993)
ATT 95 (1921)
SAT 92 (1993)
DRT 93 (1938)

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              82  64  92  64  91 /   0   0   0  -   20
Austin Bergstrom Intl Airport  82  62  92  61  92 /   0   0   0  10  20
New Braunfels Muni Airport     82  62  92  63  91 /   0   0   0  -   20
Burnet Muni Airport            83  62  88  60  90 /   0   0   0   0  10
Del Rio Intl Airport           87  64  92  61  93 /   0   0   0   0   0
Georgetown Muni Airport        82  62  90  60  90 /   0   0   0   0  20
Hondo Muni Airport             84  64  94  63  93 /   0   0   0  -   10
San Marcos Muni Airport        83  62  92  62  91 /   0   0   0  -   20
La Grange - Fayette Regional   83  62  90  67  90 /   0   0   0  10  20
San Antonio Intl Airport       83  65  92  66  90 /   0   0   0  -   10
Stinson Muni Airport           83  65  94  66  92 /   0   0   0  -   20

&&

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

$$

Aviation...BMW
Short-Term/Long-Term...Huffman
Public Service/Data Collection...33



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