National Weather Service Raw Text Product

Displaying AFOS PIL: AFDEWX Received: 2018-09-18 16:26 UTC


027 
FXUS64 KEWX 181626 AAA
AFDEWX

Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
1126 AM CDT Tue Sep 18 2018

.UPDATE...
The forecast has been updated to remove the mention of morning fog.
Minor updates have also been made to the sky cover, dewpoints and
winds. We could still see an isolated shower or thunderstorm across
Val Verde county and will leave a low chance in the forecast for
today. 

&&

.PREV DISCUSSION... /ISSUED 630 AM CDT Tue Sep 18 2018/ 

AVIATION...
At KAUS/KSAT/KSSF, MVFR CIGs mix to VFR skies late morning, then 
MVFR CIGs return overnight only to mix to VFR again Wednesday midday.
Brief IFR CIGs are possible early this morning and again overnight. 
S to SE winds of less than 10 KTs prevail. A weak impulse may produce
--SHRA nearby, though no impacts are expected and have left out any 
mention.

At KDRT, IFR CIGs rise to MVFR late morning and VFR skies early 
afternoon. MVFR CIGs return late tonight. SE winds of 7 to 14 KTs 
prevail. A weak impulse may produce --SHRA nearby, though no impacts
are expected and have left out any mention.

PREV DISCUSSION... /ISSUED 408 AM CDT Tue Sep 18 2018/ 

SHORT TERM (Today through Wednesday)...
Stratus spreading across the Rio Grande Plains towards the Edwards
Plateau and Hill Country early this morning and a mid-level cloud
deck spreading south out of Central Texas will help limit overall fog
development save for the Coastal Plains. Expect visibilities in the 
2-5 mile range in the Coastal Plains this morning with any fog that 
develops quickly dissipating after sunrise and onset of daytime 
heating/mixing. 

The KDFX VAD wind profile is showing a 20-25 knot low level jet 
early this morning, which has been aiding in the developing of spotty
showers across portions of Val Verde, Edwards, Kinney, and Maverick 
counties. Expect this activity to persist through the remainder of
the morning hours with a secondary round of showers and thunderstorms
possible for Val Verde later this afternoon and evening as 
convection moves off the higher terrain of Mexico. Farther to the 
east, KGRK and KEWX were picking up on light returns across Central 
Texas (coincident with the aforementioned mid-level cloud deck). This
is associated with a subtle area of positive potential vorticity 
advection/ shortwave trough rotating under the upper ridge over North
Texas. (A weak indication of this shortwave trough is evident moving
south on the 6.95 micron channel on GOES water vapor imagery early 
this morning.) Evening aircraft soundings out of Austin showed a 
fairly dry layer of air below 10,000 feet and have included no 
mention of rain for the eastern counties this morning as only virga
is expected. Subsidence associated with the upper ridge expanding 
farther east into Texas today is expected to result in additional 
column drying and have maintained the dry forecast for the rest of 
the area this afternoon and evening. Otherwise, drier conditions will
allow for temperatures to warm a few degrees above yesterday's highs
with most areas in the mid 80s to lower 90s.

Patchy fog may return again to the Coastal Plains overnight with a 
stronger low level jet across the Rio Grande keeping isolated showers
in the forecast along the river. Dry conditions are expected 
elsewhere with morning lows in the upper 60s to lower 70s. 
Wednesday's forecast will remain fairly similar to today's with the
isolated showers and a few thunderstorms possible across the extreme
western forecast area. The upper ridge over North Texas this morning
slides towards the lower Mississippi during the day Wednesday, which
should not have any sensible weather impacts beyond possibly 
moderating high temperatures a degree or two below today's.

LONG TERM (Wednesday Night through Monday)...
A pattern change begins on Wednesday night as a shortwave trough 
evident over the northwest Gulf on water vapor imagery this morning 
lifts into southern Texas ahead of an upper trough approaching the 
Northern Plains from the Pacific. The passage of the Pacific trough 
on Thursday will allow for a lee side low over the High Plains to 
deepen and eject across the Plains. Increasing southerly/onshore low 
level flow associated with this low will allow for isolated to 
scattered showers along the Rio Grande Plains Saturday night. 
Scattered showers and thunderstorms are then expected to blossom 
across the region during the day Thursday owing to the presence of 
the Gulf shortwave lingering over the region. Increased cloud cover 
and rain is expected to keep temperatures generally in the 80s during
the day Thursday.

The Gulf shortwave/upper weakness remains over the region Thursday 
night through Saturday, resulting in scattered to possibly numerous 
showers and thunderstorms each day. Pacific moisture associated with 
a tropical disturbance off Baja California is expected to be drawn 
towards Texas sometime late Thursday or Friday, possibly increasing 
rain coverage and introducing the potential for locally heavy rain 
for parts of the region Friday and Saturday. However, with no 
evident low level focus for rain development during this time and 
varying trajectories for the Pacific moisture (NAEFS and GEFS progs 
focusing more moisture over New Mexico and West Texas, deterministic 
GFS bringing it straight towards the Rio Grande Plains), there is 
still some uncertainty in what impacts this moisture may actually 
have for the region. Upper ridging builds back overhead Sunday into 
Monday, allowing for decreasing rain chances through the end of the 
weekend. Expect highs Friday and Saturday in the low to mid 80s with 
temperatures gradually warming Sunday and Monday with the ridge 
overhead.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              92  73  91  74  88 /  10  10  10  10  30 
Austin Bergstrom Intl Airport  92  71  91  73  88 /  10  10  10  10  30 
New Braunfels Muni Airport     92  70  89  73  87 /  10  10  10  10  30 
Burnet Muni Airport            90  71  89  72  86 /  10  10  10  10  30 
Del Rio Intl Airport           89  73  87  74  85 /  10  20  10  20  40 
Georgetown Muni Airport        93  72  91  72  88 /  10  10  10  10  30 
Hondo Muni Airport             89  71  87  73  87 /  10  10  10  10  30 
San Marcos Muni Airport        91  71  90  73  88 /  10  10  10  10  30 
La Grange - Fayette Regional   93  73  92  74  89 /  10  10  10  10  30 
San Antonio Intl Airport       91  72  89  74  87 /  10  10  10  10  30 
Stinson Muni Airport           91  73  89  74  88 /  10  10  10  10  30 

&&

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

$$

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