984
FXUS64 KCRP 202052
AFDCRP

Area Forecast Discussion
National Weather Service Corpus Christi TX
352 PM CDT Sat Jul 20 2024

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

.SHORT TERM...
(Tonight through Sunday night)
Issued at 253 PM CDT Sat Jul 20 2024

Key Messages:

- Shower/thunderstorm chances low to medium across South Texas, high
  over the waters

Rest of Today and Tonight

An upper air trough over the region combined with minimum PVA at
500mb and precipitable water (PWAT) values up around 2.15 inches
along the coast and lower inland will lead to a low to medium chance
(20-35%) for showers/thunderstorms today. Activity today will be
focused along the seabreeze and over the waters. Extending further
inland as the sea breeze moves east to west across the region. The
loss of daytime heating during the overnight hours will result in
decreased precipitation, with mainly dry conditions.

Sunday and Sunday Night

Looking ahead to tomorrow, we anticipate an increase in low-level
flow along with the approach of a weak tropical wave. This will
further increase moisture levels, pushing PWAT values up to around
2.25 inches. The combination of increased moisture and PVA from 850-
500mb will lead to higher rain chances, particularly over the Gulf
Waters (with a medium to high chance 40-75%) where moisture and mid-
level lift support are strongest, while the Coastal Bend and the
Coastal Plains will see low to medium rain chances, ranging from 20-
50%.

Temperatures and Heat Index

Temperatures will remain in the 90s across South Texas. Combined
with dewpoints in the mid to upper 70s, heat index values are
expected to range from 105-109 degrees. This will continue to pose a
minor to moderate risk of heat-related impacts for the region.

&&

.LONG TERM...
(Monday through next Friday)
Issued at 253 PM CDT Sat Jul 20 2024

Key Messages:

- Increasing moisture will lead to higher rain chances next week.

- Marginal Risk of excessive rainfall and flash flooding Monday.

- Slight Risk of excessive rainfall and flash flooding Tuesday and
  Wednesday.

Only minor changes to the inherited Extended forecast package were
required today, mainly just adjusted the QPF values based on the
latest forecast from WPC.

A trough extending from the Great Lakes region southwestward into
South Texas will combine with plentiful moisture and several mid-
level disturbances to lead to unsettled weather conditions across
the region through the end of forecast cycle. PWATs are progged to
steadily increase over the area through mid week, going from around
2" on Monday to near 2.3-2.5" by Wednesday, which is closer to the
99th percentile for this time of year. The passing of the several
weak shortwaves aloft, the presence of a moderately unstable
atmosphere (SBCAPE values ~1000-2000 J/kg) and some weakening of the
cap will provide daily chances for showers and thunderstorms through
the end of the work week.

The highest precip and convective chances can be expected Tuesday to
Thursday period, when PoPs increase to around a 60-90%. Latest
guidance from WPC indicates total rainfall accumulation of 2-4"
through Friday, with the highest amounts forecast over northern and
eastern portions of the CWA mainly on Wednesday. The risk of
excessive rain goes from Marginal (level 1 out of 4) over northern
zones on Monday to a mixture of Marginal and Slight (level 2 out of
4) risks areawide on Tuesday, into a widespread Slight risk by
Wednesday. This indicates there is at least a 5-15% chance of
rainfall exceeding flash flood guidance during the aforementioned
period. Certainly something to pay close attention to as we continue
to fine tune the forecast over the coming days.

Aside from the convective and flash flooding potential, no other
hazards are anticipated across South Texas through late in the week.
Though, models are beginning to indicate the upper pattern to change
with the development of a low either over north central Mexico or
over the state next weekend. But, that is beyond the scope of this
forecast package. Temperatures will remain at near normal levels
through the end of the week mainly due to the increased cloud
coverage and rainfall probabilities.

&&

.AVIATION...
(18Z TAFS)
Issued at 1227 PM CDT Sat Jul 20 2024

VFR conditions so far today have been accompanied by light and
variable winds that will shift from the southeast this afternoon.
There`s a 15-35% chance for showers and thunderstorms this
afternoon along the seabreeze with the upper end chances across
VCT. Otherwise expecting an increase of winds >11 kts until
shortly after sundown. Fog across the Coastal Plains early
tomorrow morning may result in MVFR conditions at VCT/ALI,
otherwise VFR conditions will prevail.

&&

.MARINE...
Issued at 253 PM CDT Sat Jul 20 2024

Weak onshore flow this afternoon will persist through the weekend.
Low chance for showers and thunderstorms tonight, will ramp up to a
40-75 percent chance Sunday. Weak to occasionally moderate south
to southeasterly flow will persist through next week. Low to
medium rain chances of 20 to 50 percent early Monday morning will
increase to medium to high chances of 60 to 90 percent heading
into middle of next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi    78  94  79  94 /   0  30  10  40
Victoria          75  92  76  92 /  10  40  20  70
Laredo            77  99  77  99 /  10  10  10  20
Alice             75  97  76  96 /   0  30   0  40
Rockport          80  92  80  92 /  10  40  20  50
Cotulla           78 101  78  98 /   0  10  10  30
Kingsville        77  95  77  95 /   0  30  10  40
Navy Corpus       80  90  81  90 /  10  40  20  40

&&

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

$$

SHORT TERM...BF/80
LONG TERM....ANM/88
AVIATION...BF