Flash Flood and Flooding in Texas, August 16 to 17, 2022

Area Forecast Discussion
National Weather Service Corpus Christi TX
402 AM CDT Tue Aug 16 2022

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(Today through Wednesday)
Issued at 402 AM CDT Tue Aug 16 2022

- Drier conditions are expected across South Texas today and
Wednesday. However, there will still be a low chance (around 20%)
of showers and thunderstorms across the Coastal Bend and Coastal
Plains.

Satellite imagery this morning shows the area of low pressure
responsible for Sunday and Monday's heavy rainfall continues to
lift northwest into West Texas and Southern New Mexico. While GOES
water vapor imagery indicates drier air in the mid levels over
South Texas, satellite derived PWAT ranging from 1.6 to 2 inches
indicate ample low level moisture is still in place to result in a
conditionally unstable atmosphere. Regional radar imagery shows
isolated convection already developing along the coastal waters
and immediate coast. HREF guidance indicates that additional
convection will develop along the Texas coast through 10 AM before
spreading inland during the afternoon hours.

With respect to precipitation amounts, chances are low to moderate
(20-30 percent) that convection today will result in any
measurable precipitation. 00Z HREF guidance indicates that any
robust convection that develops could produce rainfall totals of
2-3 inches today. Even with the rainfall South Texas has received
over the past 48 hours, flash flood guidance ranges from 2-3
inches outside of urban areas. Based on the combination of drier
mid-level air, decreasing upper level support for ascent, limited
surface forcing, and higher end precipitation totals only
approaching flash flood guidance, the potential for any additional
flash flooding today looks to be very low.

The atmosphere is expected to be even less conducive for
convection on Wednesday. Therefore, precipitation chances are less
than 20 percent with showers being even more isolated than today.
This should allow for slightly warmer temperatures, which in
combination with the increased surface moisture will contributed
to apparent temperatures increasing to 105-109 during the
afternoon hours on Wednesday.

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 402 AM CDT Tue Aug 16 2022

Key messages:

- Drier Thurday and Friday with rain chances returning this weekend.

- Heat index values between 105-109 for much of South Texas Thursday
through next Tuesday.

- A tropical wave will enter the Bay of Campeche Thursday

The upper level ridge is expected to weaken Thursday as a broad
trough digs south across the Southeast United States and into the
northern Gulf coast. Models continue to show this feature ejecting a
frontal boundary into Central Texas Thursday, which could
potentially sag into South Texas Friday. With PWATs ranging from
1.77-2" Friday, scattered showers and thunderstorms will be possible
across the Coastal Bend and Victoria Crossroads if the boundary
indeed does sag into the region.

With very little change from the previous forecast package, models
continue to show a tropical wave (20% chance of development in the
next 5 days as per the National Hurricane Center) entering the Bay
of Campeche Thursday morning. Models are also continuing to show the
feature moving northward through the end of the work week,
potentially approaching the Mexico/Texas border Saturday. If this
verifies, additional tropical moisture can be advected into South
Texas leading to showers and thunderstorms across the area this
weekend with rain chances tapering off early next week.

Cooler highs are expected through the long-term with highs ranging
from the lower 90s near the coast to near 102 degrees across the
Brush Country. Despite the cooler highs, added moisture across the
region will promote elevated heat index values across much of the
area with heat indices ranging from 105-109 degrees. Lows will
remain mild with temperatures ranging from the mid 70s to lower 80s.

&&

.AVIATION...
(06Z TAFS)
Issued at 1229 AM CDT Tue Aug 16 2022

VFR conditions are expected at area TAF sites through 10Z before
areas of fog could develop resulting in TEMPO MVFR to IFR
visibility restrictions. Any fog that does develop should
dissipate by 14Z. Predominately VFR conditions are expected
through the day tomorrow. Isolated showers and thunderstorms could
develop along the Gulf breeze during the afternoon hours. However,
the probability of operational impacts at area TAF sites is less
than 30 percent and no mention of convection was included in the
TAFs.

&&

.MARINE...
Issued at 402 AM CDT Tue Aug 16 2022

Isolated showers and thunderstorms will be possible over the
coastal waters during the morning through mid-afternoon hours on
Tuesday and Wednesday. Otherwise, southeast winds of 10-15 knots
can be expected with seas of 2-3 feet. Weak to moderate
southeasterly flow is expected Thursday and Friday with winds
increasing to more moderate levels Saturday and Sunday as a
tropical wave potentially approaches the coastal waters. The
increase in winds Saturday and Sunday will result in periods of
Small Craft Exercise Caution conditions. Scattered showers and
thunderstorms will be possible Saturday morning through early next
week, with the potential for gusty winds within any possible
thunderstorm. &&

.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi    90  77  92  76 /  30   0  20   0
Victoria          94  75  97  75 /  20   0  20   0
Laredo            96  77  96  78 /  10  10  10   0
Alice             94  75  96  74 /  40   0  20   0
Rockport          94  81  94  81 /  20   0  20   0
Cotulla           98  77 100  78 /  20   0  10   0
Kingsville        91  76  93  75 /  30   0  20   0
Navy Corpus       89  83  89  81 /  20   0  10   0

&&

.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

SHORT TERM...TWH/91
LONG TERM....JCP/84
AVIATION...TWH

Hazardous Weather Outlook...UPDATED
National Weather Service Corpus Christi TX
357 PM CDT Mon Aug 15 2022

TXZ229>234-239>247-342>347-442-443-447-161345-
La Salle-McMullen-Live Oak-Bee-Goliad-Victoria-Webb-Duval-Jim Wells-
Inland Kleberg-Inland Nueces-Inland San Patricio-Coastal Aransas-
Inland Refugio-Inland Calhoun-Coastal Kleberg-Coastal Nueces-
Coastal San Patricio-Aransas Islands-Coastal Refugio-Coastal Calhoun-
Kleberg Islands-Nueces Islands-Calhoun Islands-
357 PM CDT Mon Aug 15 2022

This Hazardous Weather Outlook is for south Texas.

.DAY ONE...This afternoon and tonight.

Flood Watch is in effect for the Brush Country through 7 PM this
evening. Scattered showers and thunderstorms with locally heavy
rainfall will continue until early this evening. Additional rainfall
amounts of 1 to 2 inches with isolated amounts of 3 inches or more
possible, which may lead to Flash Flooding.

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

Maximum Heat Index values of 105 to 109 degrees can be expected each
afternoon.

Isolated to scattered showers and thunderstorms will be possible
Thursday through the weekend.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

GMZ231-232-236-237-250-255-270-275-161345-
Baffin Bay and Upper Laguna Madre-Corpus Christi and Nueces Bays-
Copano, Aransas, and Redfish Bays-
San Antonio, Mesquite, and Espiritu Santo Bays-
Coastal waters from Baffin Bay to Port Aransas out 20 NM-
Coastal waters from Port Aransas to Matagorda Ship Channel out 20 NM-
Waters from Baffin Bay to Port Aransas from 20 to 60 NM-
Waters from Port Aransas to Matagorda Ship Channel from 20 to 60 NM-
357 PM CDT Mon Aug 15 2022

This Hazardous Weather Outlook is for Gulf of Mexico.

.DAY ONE...This afternoon and tonight.

No hazardous weather is expected at this time.

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

Isolated showers and thunderstorms can be expected Thursday through
the weekend.

TMT