Areal Flood Advisory 76, NWS Austin/San Antonio, TX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
307 PM CDT Mon May 24 2021

.SHORT TERM (Today through Tuesday)...
The area still remains in the same wet pattern that has been
bringing locally heavy rainfall to the area. A persistent area of
high pressure resides in the SE CONUS that keeps pumping rich
tropical moisture over South Central Texas. As an upper disturbance
continues to move through the longwave trough, instability across
the area coupled with daytime heating, is allowing for scattered
showers with isolated thunder to develop over areas in our eastern
counties. These counties have had more than enough rain over the past
several day to soak through the ground, that additional heavy rain
could lead to flash flooding. Lavaca, Dewitt, Fayette, and Gonzales
counties are currently still in a Flash Flood Watch through the
afternoon. Areas east of HWY 281 will continue to see this showery
activity until sunset.

Tmrw, there is not much change in the pattern. Plume of moisture
continues to flow through weakness within the trough to the west and
the high pressure centered to the east. There may be a slight
eastern shift to this high center that would pull the deepest
moisture further east, but this does little for our eastern zones,
but may leave areas closer to HWY 281 slightly drier. Further west,
a dry line may initiate thunderstorms in West Texas that may
progress into the Edwards Plateau.

Overnight temperatures and overall conditions will be warm, wet and
muggy for both tonight and tomorrow night. With a little less cloud
coverage tmrw, daytime highs will be able to climb a few
degrees warmer than today and still a few degrees below normal.

&&

.LONG TERM (Tuesday Night through Monday)...
A very gradual decrease in moisture levels along with some
strengthening of the subtropical ridge axis will lead to less
coverage of showers and thunderstorms across south central Texas
through the middle of the upcoming week. On Wednesday, we will only
mention a 20-30% chance for showers and thunderstorms for areas
along and east of the I-35/I-37 corridors. As the upper level ridge
builds in and shifts the more active flow aloft to our north, we will
keep the forecast dry for most areas Thursday into early Friday. For
Friday afternoon, the models begin to show different scenarios with
regard to rain chances. The GFS keeps things on the dry side, while
the ECMWF shows some rain chances over the Hill Country near the
leading edge of a weak cold front. For now, we will keep a low chance
of rain in the forecast over the Hill Country and adjacent southern
Edwards Plateau.

For the upcoming weekend into early next the models differ with
regards to the surface pattern, with the ECMWF keeping a weak front
in the region on Saturday with east to southeasterly winds, while the
GFS and Canadian models keep the front farther east of our region.
The mid and upper level flow could be active from time to time,
mainly over central and north Texas. For now, we will only keep a
low chance (20-30%) for showers and thunderstorms in the forecast on
Saturday with a dry forecast for Sunday and Monday.

We should see a gradual warming trend for the long term portion of
the forecast. We will see a fair amount of late night and morning
cloud cover, but should manage to see some clearing in the afternoon
and evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              80  70  83  71  86 /  90  30  60  10  20
Austin Bergstrom Intl Airport  81  69  83  70  86 /  90  30  60  10  20
New Braunfels Muni Airport     83  71  86  72  87 /  70  20  50  10  10
Burnet Muni Airport            79  69  83  70  85 /  80  20  40  10  10
Del Rio Intl Airport           89  74  91  75  92 /  20  30  10  20   0
Georgetown Muni Airport        79  69  83  70  85 /  80  20  50  10  20
Hondo Muni Airport             85  71  87  72  89 /  30  10  30  10  -
San Marcos Muni Airport        82  69  84  70  87 /  80  30  50  10  20
La Grange - Fayette Regional   82  71  84  73  87 /  80  40  70  -   30
San Antonio Intl Airport       83  71  85  72  87 /  60  20  50  10  10
Stinson Muni Airport           85  72  87  73  88 /  50  20  40  10  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 10 PM CDT this evening for De Witt-Fayette-
Gonzales-Lavaca.

&&

Short-Term/Aviation...YBVP
Long-Term...Platt
Decision Support...17

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
355 AM CDT Mon May 24 2021

TXZ171>173-183>194-202>209-217>225-228-250900-
Llano-Burnet-Williamson-Val Verde-Edwards-Real-Kerr-Bandera-
Gillespie-Kendall-Blanco-Hays-Travis-Bastrop-Lee-Kinney-Uvalde-
Medina-Bexar-Comal-Guadalupe-Caldwell-Fayette-Maverick-Zavala-
Frio-Atascosa-Wilson-Karnes-Gonzales-De Witt-Lavaca-Dimmit-
355 AM CDT Mon May 24 2021

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

.DAY ONE...Today And Tonight.

Locally heavy tropical downpours are expected again today for
areas mainly along and east of I-10/37 corridor. Localized
flooding may be possible, with the greatest concern focusing
across portions of the coastal plains.

A Flash Flood Watch remains in effect through this evening for
Fayette, Gonzales, DeWitt, and Lavaca counties, where additional
amounts of 1 to 2 inches of rainfall, with isolated higher amounts
up to 4 inches, could occur today, producing flooding.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Locally heavy tropical downpours are possible again Tuesday for
areas mainly along and east of highway 281. Localized flooding
may be possible, with the greatest concern focusing across
portions of the coastal plains.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report any localized and/or flash
flooding to the National Weather Service.