Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/05/22
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
1036 PM CDT Mon Apr 4 2022
.UPDATE...
The isolated storms in Mexico have waned. A few convective allowing
models suggest some re-development across Mexico, the Rio Grande
Plains, and Winter Garden regions through the overnight. Farther
east and north, convection has been almost non-existent across the
CWA. AMDAR soundings the past hour out of AUS indicate the cap has
eroded, but not at SAT. SPC mesoanalysis reveals a pocket of no CIN
around Austin, so we will see how far south convection along the
boundary to the north can build. 00Z convective allowing models are
not indicating this will happen. Overall, we have lowered PoPs for
the remainder of tonight for most areas.
Finally, some of the 00Z convective allowing models are now
regenerating convection Tuesday afternoon ahead of the boundary
across the far southwest CWA, into the Winter Garden and Brush
Country. This will be looked at further by the mid shift. Should this
occur, we will have to watch for the potential for some downbursts
producing strong wind gusts given the very hot temperatures and
inverted V forecast soundings producing high DCAPE values in this
area.
&&
.FIRE WEATHER...
We have upgraded the Fire Weather Watch for Tuesday to a Red Flag
Warning and expanded into portions of the northern Hill Country.
While sustained winds might not be meeting criteria, the every low
humidity, wind gusts forecast, and recent fire activity and behavior
in this region on similar weather days suggests a Red Flag Warning
is warranted. Red Flag Warnings are also likely across larger
portions of the area Wednesday through Friday.
&&
.PREV DISCUSSION... /ISSUED 646 PM CDT Mon Apr 4 2022/
UPDATE...
Convection developed across Mexico late this afternoon, and a recent
supercell split has produced a left mover that is impacting portions
of southern Val Verde County with a large hail threat. There is
lower confidence on whether the right movers make it across the
border, however additional upstream convection is possible through
the remainder of the evening hours and into portions of the overnight
along the Rio Grande and across the Winter Garden region as better
large scale forcing and streak wrap into the region. We have updated
to explicitly include a mention of severe along the Rio Grande.
Farther east confidence in convective potential remains much lower,
largely driven by the cap still in place seen on the last hours AMDAR
soundings out of AUS and SAT. Recent runs of the HRRR do not suggest
much development east into the Hill Country and I-35 corridor
tonight. We will continue to monitor trends.
AVIATION (00Z TAFs)...
VFR conditions prevail across South Central Texas. We are tracking
supercells across Mexico, with one split taking place and the left
mover approaching the vicinity of DRT. Large hail is likely occurring
in this storm. TSRA has been indicated in the DRT TAF through 03Z.
Confidence remains low on coverage of additional TSRA activity late
this evening and overnight farther east given the cap in place. We
will monitor trends through the evening for possible amendments to
the SAT and AUS TAFs, but at this time due to the low confidence we
have not included TSRA. Otherwise, MVFR ceilings developing 02Z-04Z
along and east of I-35 and I-37, lower to IFR 04Z-07Z and expanding
west into portions of the Hill Country.
PREV DISCUSSION... /ISSUED 338 PM CDT Mon Apr 4 2022/
SHORT TERM (Tonight through Tuesday Night)...
Latest surface observations and visible satellite photos show
abundant moisture across the area this afternoon. As of 3 PM, dew
point temperatures are in the 60s over most areas and up to the
lower 70s to the east of Interstate 35. Area Doppler radars have
been picking up on light to moderate showers since late this morning
where deeper moisture resides. The shower activity is expected to
continue for the rest of this afternoon and evening with
thunderstorm activity also increasing later this afternoon as the
cap weakens.
The scenario for late this afternoon and evening depends on how
quickly the cap erodes across the warm sector, and how far east the
dryline advances between northeast Mexico and Val Verde County. In
addition to all that, an upper-level short wave across the four
corners region is forecast to push east and into the Southern Plains
through the period to support strong to severe thunderstorms across
the area, especially over the Hill Country.
Earlier HiRes model runs were indicating convective initiation
across central Texas ahead of the dryline and pushing a line of
storms to the southeast. However, for the last several runs of the
HRRR, strong to severe thunderstorms have been depicting activity
crossing the international border between 5 and 6 PM with no cap in
place and MLCAPE values in the 1700 and 1800 J/kg range. Also, mid
lapse rates are coming in around 6 and almost 9 C/Km for a
moderately unstable atmosphere. On top of that, effective shear is
coming in around 60 knots. With all these ingredients in place and
if the HRRR pans out, expect storms to develop quickly and become
strong to severe with the main hazards being damaging winds and
large hail. Can`t rule out an Isolated tornado or two. Otherwise,
this is a low confidence event as models are having difficulties on
sharing a unified solution.
Once the activity pushes to the east of our area on Tuesday, all
eyes turn to fire weather concerns as dry air and breezy conditions
take place as the dryline pushes into the Hill Country and the Rio
Grande. We have opted to issue a Fire Weather Watch for Val Verde,
Edwards, Real and Kinney Counties from 1 PM through 7 PM Tuesday.
The other item of concern during the day on Tuesday will be the hot
temperatures with record highs expected for a lot of areas. Highs
will range from the lower to mid 90s across the Hill Country near
100 across the Rio Grande. See more details in the climate section.
LONG TERM (Wednesday through Monday)...
A cold front will make steady southward progress across the region
on Wednesday. Gusty north winds will spread in behind the front,
along with cooler temperatures. The coolest readings are anticipated
across the Hill Country where highs will peak in the mid to upper
70s. Farther south into the Rio Grande and coastal plains, highs will
still manage to warm into the upper 80s to lower 90s as a stout low-
level thermal ridge will still be in place. Some moisture will be in
place across the coastal plains just ahead of the front. Confidence
in precipitation along the front is low, so we will keep the forecast
dry at this time. A reinforcing shot of surface high pressure moves
in on Thursday and this will keep highs down in the 70s to near 80.
Surface winds finally ease Thursday night into Friday morning. With
winds decreasing and dry air and clear skies in place, overnight lows
will drop into the upper 30s to upper 40s across most areas. We can`t
completely rule out some lower to mid 30s in wind sheltered/low-
lying areas across the Hill Country. Highs on Friday will again range
from the mid 70s to lower 80s, with another cool night in store
Friday night into Saturday morning. A few of the models show return
southerly flow kicking in a little sooner on Saturday. This could
alter the low temperature forecast for Friday night into Saturday
morning. For now, we will show most areas in the upper 30s to upper
40s.
Southerly flow in the low-levels quickly ramps up for the upcoming
weekend into early next week, resulting in a warming and moistening
trend. We will keep the forecast dry through the weekend given the
fairly stable northwest flow aloft. By late Sunday into early Monday,
there are signs the flow aloft transitions to the southwest. For now,
we will only mention a slight chance for showers along the Highway 77
corridor into portions of I-35 on Monday.
FIRE WEATHER...
Elevated to critical fire weather conditions and opportunities for
Fire Weather Watches and Red Flag Warnings return on Tuesday and
continue through Saturday. By the way and as mentioned above, there
is a Fire Weather Watch for the northwest of the area from 1 PM to 8
PM Tuesday for low humidities and breezy conditions. Minimum
humidities will plunge into the single digits and teens across our
western areas on Tuesday and Wednesday, then continue through
Saturday. Minimum humidities in the 20s and 30s across our eastern
areas on Tuesday and Wednesday, also plunge into the single digits
and teens on Thursday, then continue through Saturday. Humidities
recover a little on Sunday. Winds will be breezy and gusty most
days. Westerly winds on Tuesday turn northerly on Wednesday and
Thursday, then turn southerly out west on Friday and all areas on
Saturday. Any wetting rains from showers and thunderstorms today and
tonight will be spotty and will likely not contribute to any fuel
moisture. As a result, fuels are expected to dry even more during
the next several days.
CLIMATE...
Record High Temperatures for April 5
Austin Camp Mabry 94
Austin Bergstrom 89
San Antonio 93
Del Rio 96
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 65 93 62 79 52 / 20 0 0 0 0
Austin Bergstrom Intl Airport 64 92 60 80 49 / 20 0 0 0 0
New Braunfels Muni Airport 66 94 60 84 50 / 20 - 0 0 0
Burnet Muni Airport 60 92 58 77 48 / 20 0 0 0 0
Del Rio Intl Airport 63 99 62 89 55 / 20 0 0 0 0
Georgetown Muni Airport 62 92 60 78 50 / 20 0 0 0 0
Hondo Muni Airport 63 97 59 89 49 / 20 - 0 0 0
San Marcos Muni Airport 64 93 60 82 49 / 20 - 0 0 0
La Grange - Fayette Regional 69 90 63 81 50 / 20 - 0 0 0
San Antonio Intl Airport 66 94 62 84 53 / 20 - 0 0 0
Stinson Muni Airport 69 97 65 89 55 / 20 - 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 1 PM to 8 PM CDT Tuesday for Bandera-Edwards-
Gillespie-Kerr-Kinney-Llano-Real-Uvalde-Val Verde.
&&
$$
Short-Term/Aviation...76
Long-Term...KCW