589
FXUS64 KEWX 091350
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
850 AM CDT Thu May 9 2024

...New UPDATE...

.UPDATE...
Issued at 850 AM CDT Thu May 9 2024

We have cancelled the dense fog advisory for this morning as
visibilities are 1 mile or greater in mist and haze. We have also
inserted haze into the forecast through the day, south of the front
and east of the dryline, given the background residual smoke in the
air originating from seasonal burnings in Mexico and Central
America. Minor updates were made on timing of storms later this
afternoon and evening.

&&

.SHORT TERM...
(Today through Friday)
Issued at 354 AM CDT Thu May 9 2024

Morning surface observations show high moisture levels across all of
south central Texas with dewpoints currently in the lower to upper
70s. Fog development continues and as winds begin to ease across
portions of the Hill Country and I-35 corridor, some dense fog is
expected. We have issued a Dense Fog Advisory until 11 AM for the
above mentioned areas. We will continue to monitor and may need to
expand the Advisory pending observational trends.

The dryline is still expected advance eastward beginning mid-morning
and continuing through the afternoon hours. Meanwhile, a cold front
will slowly work southward out of north Texas into portions of west
central Texas this afternoon. Hi-res models continue to initiate
convection along the intersection of the front and dryline this
afternoon somewhere between Mills county southward into northern
Llano and Burnet counties. The late afternoon hours appear to be the
most favored time for convection initiation. However, we are noting
that at least a few of the hi-res models manage to develop some
convection earlier than this over portions of the southern Edwards
Plateau near Junction by late morning. Convection will then likely
continue to develop along the southward moving cold front across the
remainder of the Hill Country and into the I-35 corridor, mainly
north of San Antonio during the early evening hours. Large to very
large hail and damaging winds are the main severe weather concerns.
However, a tornado can not be ruled out, especially where discrete
supercells interact with any boundaries. SPC has expanded the
Enhanced Risk area (level 3 of 5) to cover areas generally north of
a Fredericksburg to San Marcos to La Grange line. South of this line
to a Rocksprings to Cuero line could still see some isolated severe
storms with a Marginal to Slight (level 1 to 2 of 5) in place. It
will be very warm to hot again across south central Texas with highs
ranging from near 90 to near 106 degrees. Another record high may be
tied or broken out west at Del Rio. We could be close to the record
high at San Antonio as well.

Some relief in the temperatures will arrive tonight as northerly
winds behind the cold front usher cooler air into the region. Lows
will ease back into the mid 60s to lower 70s. On Friday, expect
highs in the lower 80s to lower 90s, with a few of the models
trending upward slightly with temperatures compared to previous
runs. We will keep a low chance for rain in the forecast for the Rio
Grande plains into the Hill Country.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 321 AM CDT Thu May 9 2024

Our active stretch of weather looks to continue into the long term
period as southwest flow aloft continues to feed mid-level Pacific
moisture into the region.

Saturday and Sunday will feature the best chance for rain through
the extended period with an upper level low over the Four Corners
finally becoming absorbed by the upper jet and sliding eastward.
Early Saturday, a surface high will be in place over north Texas,
with flow turning back out of the east-southeast over South Central
Texas as early as Friday night, we will start to see showers and
perhaps some isolated thunderstorms develop under isentropic ascent
over the Rio Grande Plains. This activity should start to spread
eastward with time through the early afternoon Saturday, but
coverage and intensity is expected to be limited due to weak forcing
aloft. The aforementioned trough will take some time to exert its
influence on rain chances so we`ll mainly be working with the
isentropic and terrain induced lift on Saturday. Cooler temperatures
in the 70s and 80s for highs along with mostly cloudy to cloudy
skies can be expected. By late Sunday, a positively tilted 500mb
trough will be situated over the Texas Panhandle, resulting in a 100-
130 kt jet streak at the 300mb level to become situated in an ideal
location for showers and storms to develop over South Central Texas.
Within the right entrance region of this jet streak, we should see
good forcing for ascent and some decent 0-6km bulk shear. However,
the overall severe threat looks to be limited by a lack of heating
and resultant instability. We should be able to squeeze out a good
1/2-1" of QPF out of storms on Sunday afternoon over the eastern
half of the region, but once again, western zones don`t look to be
so lucky, especially where long term drought has been the worst. One
thing to note before moving on the the start of next week: There are
some signals for some heavier rainfall over the southwestern CWA and
southern Rio Grande Plains Saturday night. For now, will take this
with a grain of salt, but the potential is there for some beneficial
rains out west.

Monday looks like the most active day next week, with lingering
showers and storms as the 500mb trough exits to our east. The
dryline will also start to work its way back east on Monday
afternoon, resulting in a hot and dry forecast out west over the Rio
Grande Plains Monday afternoon. Temperatures will climb back into
the mid 90s after a bit of a break Friday-Sunday from the heat.
Beyond Monday, things look to dry out and heat up considerably, with
highs in the 88-101 range for South Central Texas on Tuesday,
Wednesday, and Thursday. By late Wednesday, things could get active
once again with a trough moving in over southwest Texas and sparking
off some storms, but this is still quite a ways out and a lot can
change between now and then.

&&

.AVIATION...
(12Z TAFS)
Issued at 650 AM CDT Thu May 9 2024

The biggest change for the most recent aviation forecast was to
increase expected vsbys and cigs along I-35 over the next few hours.
In addition, we have added a mention for brief IFR at DRT this
morning. Convection is still expected to develop over the Hill
Country around 21Z, then move southeast into the I-35 corridor. We
have adjusted the PROB30 group slightly for AUS. Confidence in
convection at SAT and SSF is lower and we will not mention in the TAF
at this time. A cold front moves through this evening, with MVFR cigs
likely to reform at all TAF sites between 07-09Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              93  68  83  65 /  30  40  10  10
Austin Bergstrom Intl Airport  91  67  83  65 /  20  40  10  10
New Braunfels Muni Airport     94  69  86  67 /  10  20  10  10
Burnet Muni Airport            89  65  80  63 /  40  40  10  10
Del Rio Intl Airport          107  74  92  72 /   0  10  40  30
Georgetown Muni Airport        89  66  81  63 /  40  50  10  10
Hondo Muni Airport            100  71  88  69 /  10  10  20  10
San Marcos Muni Airport        92  68  84  65 /  20  30  10  10
La Grange - Fayette Regional   90  71  85  67 /  20  40  10  10
San Antonio Intl Airport       95  71  86  68 /  10  20  10  10
Stinson Muni Airport           96  72  87  70 /  10  10  10  10

&&

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

&&

$$

Update...76
Short-Term...Platt
Long-Term...MMM
Aviation...Platt