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000
FXUS64 KBRO 200845
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
345 AM CDT Sat Apr 20 2024

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

.SHORT TERM...
(Today through Sunday)
Issued at 342 AM CDT Sat Apr 20 2024

A nearly zonal mid-level flow will prevail through the period. A
weak mid-level disturbance is currently moving eastward over the
Rio Grande Valley. Another, more robust 500mb short wave trough is
expected to arrive tonight. At the surface, a cold front
extending from Eastern Texas through the Texas Hill Country to
near Del Rio. This frontal boundary will begin to move south later
today and advances through the our region tonight.

Ahead of the front, today will be warm and humid with highs well
into the 80s to lower 90s, except for the upper 70s at the
beaches. Isolated showers and thunderstorms will be possible today
with the departing aforementioned shortwave and daytime heating.
However, rain chances will increase this evening as the cold front
advances through the region. There is a medium to high
probability of showers and thunderstorms across much of Deep South
Texas tonight, the best chance of convection will be along and
west of the I-69C corridor. The environment will be marginally
conducive for strong to severe thunderstorms with damaging winds
and large hail of at least one inch expected, mainly across the
Rio Grande Plains and the northern Ranchlands. SPC depicts a
Marginal Risk for Severe Thunderstorms for this area for today and
tonight. The populated areas of the Rio Grande Valley and Willacy
County remain in a general thunderstorm outlook for today and
tonight.

As for rainfall amounts, precipitable water values of near 1.8
inches should be sufficient for one-half to one inch amounts from
any thunderstorm and can not rule out 2 inches in slow moving
storms.

Lows tonight are expected to fall into the 60s with the passage
of the front. Much cooler on Sunday with highs in the 70s with
breezy north winds. Scattered lingering showers and isolated
thunderstorms will be possible on Sunday. SPC has the entire CWA
in a general thunderstorm outlook for Sunday.

Moderate Risk of Rip Currents continues into the weekend

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 342 AM CDT Sat Apr 20 2024

SPC depicts the local CWA in a general thunderstorm outlook area
Sunday night, the first period of the long term. Though a recent
cold front will be well offshore by Sunday night, the models are
keeping a mention of convection around. A couple of reasons appear
germane. First, a weak coastal trough will set up just offshore.
Second, cooler air will push toward the Sierra Madre Oriental
range just west of the Rio Grande, and the surface convergence and
maybe a little remaining mid level energy will be enough to keep
scattered showers in the area.

Sunday night itself will be cooler, with low temperatures ranging
from the mid 50 across the Upper Valley and Ranchlands to the mid
60s for places like the Lower RGV. Monday will be a transition
day to more seasonal weather. High temperatures will still be on
the cooler side, in the lower to mid 70s. Rain chances will hang
on for the day, however, but should be virtually gone by Monday
night.

Nonetheless, models do show a few coastal showers popping up on
Tuesday and Wednesday, possibly a result of the previous cold
front moving back north as a warm front. High temperatures on
Tuesday and Wednesday will rise back into the 80s with the
corresponding over- night low temps in the 60s and lower 70s. The
tail end of a cold front may swing across South Texas on Friday,
just north of our CWA, and we should have a quiet weather day.
Friday high temperatures will poke into the 90s.

To summarize, look for unsettled weather to start the long term,
with a few rumbles still possible Sunday night into Monday. The
Period will start out cool, on Monday, but temperatures will
rebound to above average by Wednesday. We`ll see a mix of clouds
and sun most of the week, and there could still be a few showers
in the area Tuesday through Thursday afternoons. Look for the
South Texas wind machine to switch on Thursday and Friday as Gulf
high pressure interacts with lower pressure over the Southern
Plains.

&&

.AVIATION...
(06Z TAFS)
Issued at 1232 AM CDT Sat Apr 20 2024

Light east to southeast winds with MVFR ceilings prevail across
Deep South Texas early this morning. MVFR ceilings will continue
overnight, with IFR ceilings possible towards sunrise. Patchy fog
is also possible, especially at BRO and HRL near sunrise. Confidence
remains too low to include dense fog and winds may stay elevated
just enough to keep visibilities above 5 miles. VFR conditions are
expected to return late this morning into the afternoon. Southeasterly
winds become breezy by later this morning. Low cloud decks with
MVFR ceilings will be possible by late this evening.

&&

.MARINE...
Issued at 342 AM CDT Sat Apr 20 2024

Now through Sunday...Weak to moderate east to southeast flow and
low to moderate seas are expected along the Lower Texas Coast
today. A weak cold front will arrive late night with scattered
showers and thunderstorms. Moderate to strong northerly winds will
develop on Sunday in the wake of the front. Small Craft
Advisories will likely be needed in wake of the frontal passage.


Sunday night through Wednesday night...Small craft advisory
conditions will be ongoing at the beginning of the period - Sunday
night - with strong northeast winds and elevated seas behind a cold
front. By Monday, marine conditions will improve with small craft
should exercise caution to low end small craft advisory conditons on
the Gulf. Monday night will feature a transition to moderate
southeast winds and moderate seas for the remainder of the long term.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             88  71  78  65 /  20  30  50  30
HARLINGEN               90  67  77  60 /  20  40  40  20
MCALLEN                 92  69  78  62 /  10  50  50  20
RIO GRANDE CITY         94  65  74  59 /  10  60  50  20
SOUTH PADRE ISLAND      80  71  76  67 /  20  30  50  30
BAYVIEW/PORT ISABEL     86  69  78  64 /  20  30  40  30

&&

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

$$

SHORT TERM...63-KC
LONG TERM....54-BHM
AVIATION...63-KC