412
FXUS64 KBRO 301716
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1216 PM CDT Tue Apr 30 2024

...New AVIATION...

.SHORT TERM...
(Today through Wednesday)
Issued at 232 AM CDT Tue Apr 30 2024

Low level moisture is surging inland as of this writing with WSR88-D
radar showing Isolated to scattered showers over the Lower Texas and
Tamaulipas coastal waters.  Some of these showers are spreading
inland this morning but mostly helping to steadily increase the
moisture content of the atmosphere across all of Deep South Texas.
Mean pwats of 1.7-1.9 inches are forecast over the region today and
Wednesday with increasing instability and a weak cap at best to
maintain a low chances (15-30%) of convection. A weak elongated
upper level disturbance moving across the south Texas this morning
initiates mid to late morning convection across the eastern two-
thirds of the County Warning Area (CWA).  The next shot of
convection is shown for Wednesday afternoon as a stronger
disturbance passes over South Central Texas placing the best chance
for thunderstorms over the NW portions of the CWA. At this time SPC
maintains a general thunderstorm outlook today and Wednesday.

Otherwise, plenty of morning and night time cloudiness with breaks
in the overcast for the afternoon hours. Temperatures continue to be
slightly elevated or above seasonal averages especially the
overnight night lows. Highs will range from 80 at the local beaches
through the 90s inland. Overnight lows only dip into the mid to
upper 70s. General moderate southeast winds with some gusts 0f 20-25
mph can be expected.

Finally, the rip current risk remains in the high category today
with a residual long period swell continuing to be directed towards
the Texas coast.  As the pressure gradient continues to weaken over
the Gulf the swell train should steadily subside over the next 12-24
hours.

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 232 AM CDT Tue Apr 30 2024

The start of the long term forecast will have a tight pressure
gradient over Deep South Texas and the Rio Grande Valley as the
sustained winds could be around 15-20 mph with some stronger gusts
close to 30 mph for Thursday. The real interesting story for the
long term forecast period is what will the cold front do. An upper-
level trough over the Rockies will be the main driving force for the
cold front. By the end of the work week the cold front is expected
to stall out over Central Texas. While there is still a little bit
of a disagreement in the models on the timing of the front, the
models have shown a timing this past run that is a bit closer. Rain
chances remain very low through the period as a weak mid-level ridge
continues to exert its influence over the area. On top of that, the
middle and upper levels of the atmosphere are very dry so there is
no moisture aloft for showers and thunderstorms to build up with.

With southerly to southeasterly flow persisting over the long term
forecast period, warm and humid conditions are expected to be the
trend. High temperatures are expected to be in the range of upper
80s along the beaches to the mid 90s for most of the region. The
western parts of Starr, Zapata, and Jim Hogg could even be in the
upper 90s. Given the amount of humidity in the air and the heat,
future shifts will need to watch over the heat index values. As
maximum heat index values could be around 105 throughout the
period. As for the low temperatures, they are expected to remain in
the 70s for all of Deep South Texas and the Rio Grande Valley.

&&

.AVIATION...
(18Z TAFS)
Issued at 1215 PM CDT Tue Apr 30 2024

Through 18z Wednesday....VFR to MVFR conditons were taking place at
the terminals as of this update under a BKN-OVC deck of cumulus
clouds with ceilings ranging between 2,500-3,000 feet AGL and
unrestricted visibilities. Due to the copious amounts of low level
moisture in place and continuous onshore flow, low level clouds will
remain in play through the 18z TAF period.

As we shift into this evening/tonight, expectations are for more
MVFR clouds to take over with lower MVFR ceilings possible later
tonight. During the day on Wednesday, cloud bases should gradually
increase but may still remain in MVFR territory through 18z
Wednesday.

Winds will remain out of the southeast between 10-15 kts. During the
day on Wednesday southeast winds are expected to gusts 20-25 kts.

&&

.MARINE...
Issued at 232 AM CDT Tue Apr 30 2024

Tuesday through Wednesday...The pressure gradient continues to
weaken over the Gulf of Mexico with a 1020mb surface ridge
extending over the Eastern Gulf and lower pressure over NE Mexico.
Residual long period swells also are showing signs of lowering
with at least another 12-24 hours before the higher swell subside
below 5 feet. Local pressure gradient along immediate coast
tightens Wednesday with moderate to fresh southeast winds expected
over the Laguna Madre. There is a medium chance (40-60%) of a
Small Craft Advisory for the Laguna Madre Wednesday afternoon.

Wednesday Night through Tuesday..Adverse marine conditions are likely
with the tight pressure gradient over the Lower Texas Coast with
wind speeds around 15-20 knots. Thus a Small Craft Exercise Caution
is likely, but a low end Small Craft Advisory cannot be ruled out.
Moving into Friday and the weekend, more favorable conditions will
be present.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             77  88  77  89 /   0  10   0   0
HARLINGEN               74  91  75  92 /   0  10   0  10
MCALLEN                 77  92  77  93 /   0  10   0  10
RIO GRANDE CITY         75  93  77  95 /   0  10  10  10
SOUTH PADRE ISLAND      76  81  76  82 /  10  10   0   0
BAYVIEW/PORT ISABEL     74  87  75  88 /  10  10   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 7 PM CDT this evening for TXZ451-454-
     455.

GM...None.
&&

$$

SHORT TERM...59-GB
LONG TERM....64-Katz
AVIATION...23-Evbuoma