Special Weather Statement, NWS Austin/San Antonio, TX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
608 AM CDT Sat Mar 28 2020

.AVIATION...
IFR/MVFR conditions, SHRA/VCTS, and S to SE winds of 5 to 10 KTs
start the forecast at the I-35 sites. Around 14Z/15Z, a frontal
passage will end SHRA/VCTS with a rapid improvement to VFR on NW
winds 10 to 15 KTs. Wind speeds gradually decrease to 5 KTs later
this afternoon into evening.

VFR skies will prevail at KDRT with NW winds increasing to 15 to 25
KTs with gusts around 30 KTs this morning into mid afternoon, then
wind speeds rapidly decrease to near 5 KTs this evening.

&&

.PREV DISCUSSION... /ISSUED 245 AM CDT Sat Mar 28 2020/

SHORT TERM (Today through Sunday)...

Area radars show light showers along the I-35 corridor near the
right entrance region of an upper level jet with showers developing
over the Edwards Plateau near the Pacific front. The parent upper
level trough will move out across the Plains today forcing the front
across our area this morning into early afternoon. The showers will
translate to the east along with the jet and front, moving east of
our area around midday. Some instability will allow for isolated
thunderstorms with a small hail a possibility.

In the wake of the front, strong northwest winds of 15 to 25 mph
with gusts up to 35 mph are expected mainly over the Rio Grande
Plains due to mixing with the stronger winds aloft. In addition, a
very dry airmass filters into our area bringing very low relative
humidities this afternoon. This combination will generate critical
fire weather conditions over the Rio Grande Plains. As a result, the
Fire Weather Watch will be upgraded to a Red Flag Warning. East of
the Rio Grande Plains to I-35/I-37 corridors, although winds will be
lighter and humidities higher, elevated to near critical fire
weather conditions are expected .

Surface high settles over our area tonight with much cooler low
temperatures due to lighter winds and low dewpoints. Surface begins
to drift off to the east on Sunday as another upper level trough
currently off the Pacific Northwest Coast moves onshore into
California. Southeasterly winds return to all areas by evening with
a slow increase in moisture.

LONG TERM (Sunday Night through Friday)...

Relatively stable and seasonal temperatures are expected through the
long term with afternoon highs in the 70s/lows in the 50s north and
east and highs in the 80s/lows 56-65 south and west, with the
coolest lows coming Wednesday morning. Precip chances will come
Monday into Monday night, then return as early as Thursday although
the picture becomes a little murky late in the week.

Sunday evening, an upper level trough over the Four Corners region
will begin to move to the southern Plains and finally begin to break
down the persistent ridging over the Gulf of Mexico. Could start to
see some isolated shower activity just before sunrise Monday as weak
isentropic upglide begins. WAA and moisture return will build
instability ahead of the cold front, and showers and a few
thunderstorms are likely during the day. This activity will be
primarily focused over the eastern 2/3rds of the area and forcing
will be strongest north. There may be a slight chance for a strong
storm in the afternoon and evening as the pre-frontal trough crosses
the I-35 corridor with CAPE perhaps exceeding 1000 J/kg and deep
shear near 50 knots. The best chance for this will come along and
east of the I-35 corridor. The highest QPF of up to 0.5" with
locally up to 1", is expected north of Austin.

Moisture will quickly exit as the front approaches and showers
should end Monday night. Weak ridging will then keep us mainly dry
through Wednesday night. Despite models beginning to diverge after
Wednesday and quite a bit of run-to-run change over this period,
long-wave northern stream troughing is expected over the east CONUS,
perhaps closing off over the Great Lakes, while split flow may
develop over the western CONUS. In addition to indications of a
shortwave trough and perhaps some moist isentropic ascent Thursday,
the longwave troughing should send another back-door front our
direction by Thursday night/Friday morning. Beginning 12Z Thursday,
have introduced slight chance POPs through the end of the period as
the model blend initialization came in dry. Looks like that period,
and especially into next weekend, has the potential to be very wet,
and CPC has highlighted the above normal precipitation chances in
their 6-14 day outlook products and the week 2 hazards. At this early
juncture, models are showing low instability availability but will
continue to refine the forecast over the coming days.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              78  52  78  60  75 /  60   0  -   20  80
Austin Bergstrom Intl Airport  77  51  78  60  76 /  60   0  -   20  80
New Braunfels Muni Airport     80  49  78  60  77 /  60   0  -   20  70
Burnet Muni Airport            76  48  74  58  71 /  40   0  -   20  90
Del Rio Intl Airport           80  50  83  61  84 /   0   0   0  10  10
Georgetown Muni Airport        78  48  77  59  72 /  50   0  -   20  90
Hondo Muni Airport             83  49  81  62  80 /  20   0  -   20  70
San Marcos Muni Airport        78  49  78  60  77 /  60   0  -   20  80
La Grange - Fayette Regional   76  51  79  62  80 /  60   0  -   20  60
San Antonio Intl Airport       82  52  78  61  77 /  50   0  -   20  70
Stinson Muni Airport           83  54  80  63  79 /  50   0  -   20  70

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM this morning to 6 PM CDT this evening
for Dimmit-Kinney-Maverick-Uvalde-Val Verde-Zavala.

&&

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

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
323 AM CDT Sat Mar 28 2020

TXZ171>173-184>194-204>209-219>225-290830-
Llano-Burnet-Williamson-Edwards-Real-Kerr-Bandera-Gillespie-
Kendall-Blanco-Hays-Travis-Bastrop-Lee-Medina-Bexar-Comal-
Guadalupe-Caldwell-Fayette-Frio-Atascosa-Wilson-Karnes-Gonzales-
De Witt-Lavaca-
323 AM CDT Sat Mar 28 2020

This Hazardous Weather Outlook is for South-Central Texas..

.DAY ONE...Today And Tonight.

Elevated to near critical fire weather conditions are expected
late this morning through mid afternoon along and west of the
I-35 and I-37 corridors for low humidities and breezy winds.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

A strong storm or two is possible Monday afternoon and evening
along and east of the I-35 corridor.

Otherwise, no hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

TXZ183-202-203-217-218-228-290830-
Val Verde-Kinney-Uvalde-Maverick-Zavala-Dimmit-
323 AM CDT Sat Mar 28 2020

This Hazardous Weather Outlook is for South-Central Texas..

.DAY ONE...Today And Tonight.

Critical fire weather conditions are expected across the Rio
Grande Plains late this morning through this afternoon for very
low humidities and breezy to windy conditions. A Red Flag Warning
is in effect from 11 AM CDT to 6 PM CDT today.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Special Weather Statement
National Weather Service Austin/San Antonio TX
651 AM CDT Sat Mar 28 2020

TXZ171-186-188-281230-
Gillespie TX-Kerr TX-Llano TX-
651 AM CDT Sat Mar 28 2020

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN KERR...GILLESPIE AND
LLANO COUNTIES UNTIL 730 AM CDT...

At 650 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Fredonia to near Hilda to Mountain Home.
Movement was east at 40 mph.

Penny size hail will be possible with these storms.

Locations impacted include...
Fredericksburg, Llano, Castell, Field Creek, Cherry Spring, Lone
Grove, Enchanted Rock State Natural Area, Cain City, Tivydale, Doss,
Willow City, Valley Spring, Rocky Hill, Harper, Prairie Mountain,
Baby Head, Mountain Home, Stolz, Eckert and Crabapple.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3057 9855 3014 9882 3014 9892 3009 9892
      3011 9947 3029 9937 3029 9930 3039 9930
      3050 9924 3050 9896 3092 9896 3092 9853
TIME...MOT...LOC 1150Z 265DEG 34KT 3097 9904 3054 9916 3019 9938

KCW