Brownsville, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

687
FXUS64 KBRO 070444
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1044 PM CST Fri Mar 6 2026

...New DISCUSSION, AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1027 PM CST Fri Mar 6 2026

Key Messages

 - Breezy conditions and gusty southeasterly winds continue
   across Deep South Texas tonight through Saturday afternoon,
   especially east of US-281, where gusts up to 30 mph, or
   greater, are possible ahead of an advancing frontal boundary.

 - The Storm Prediction Center (SPC) has placed the Northern
   Ranchlands, Upper Rio Grande Valley and most of Zapata County
   within a Marginal (Level 1 of 5) Risk as well as a Slight
   (Level 2 of 5) Risk for the northwestern tip of Zapata County
   for severe storms Saturday evening, with the primary threat of
   isolated severe wind gusts (of at least 60 mph) and large hail.

 - While generally one to three quarters of inch of rain is
   anticipated Saturday into Sunday, heavy rain is likely within
   the deepest convection or areas in which convection redevelops
   and persists, with the possibility of several inches in a few
   locations.

 - Breezy conditions and unsettled weather are possible by the
   middle of next week ahead of a cold front passing through,
   possibly next Wednesday.

 - Temperatures finally drop to near average behind the front, but
   with an increased risk of fire weather conditions into the
   later parts of next week.

&&

.DISCUSSION...
Issued at 1027 PM CST Fri Mar 6 2026

Tonight into Saturday, a 30-40 knot nocturnal low level jet and
tightened pressure gradient, resulting from a mid/upper level trough
and associated low pressure system departing the Central Plains,
continue to lead to gusty southeasterly winds across Deep South
Texas, especially along/east of US-281, where gusts up to 30 mph, or
higher, remain possible. Additionally, a High Risk of Rip
Currents continues overnight, becoming a medium risk Saturday
morning through the afternoon hours. Temperatures on Saturday are
expected to increase from the low/mid 70s in the morning to the
low/mid 90s across most inland areas in the afternoon.

The arrival of ridging aloft and building surface high pressure over
the Central and Southern Plains behind the low pressure system
pushes the low`s attendant cold front southeastward, arriving to
southern Texas by Saturday evening. As the front moves closer to our
region, deterministic guidance continues to portray it losing
forward momentum, perhaps stalling near or over the Northern
Ranchlands and areas along/west of US-281 Saturday night into Sunday
morning. Enhanced moisture pooling, instability, synoptic forcing
and lift ahead of the front increase chances of rain across Deep
South Texas Saturday evening into Sunday morning to as much as a
medium to likely (50-90%) chance, with the higher chances further
north and west. Although CAM guidance varies with the southward
extent of the cold front and areas of convection initiation, there
is fair agreement amongst this evening`s 00Z runs, portraying
strong to severe thunderstorms developing over southern Texas, and
possibly the Sierra Madre, Saturday afternoon or evening, moving
into the Rio Grande Plains, Northern Ranchlands and the Upper Rio
Grande Valley during the early evening or early nighttime hours.
The primary threats are likely to be large hail and isolated
severe and damaging wind gusts. Indeed, the RAP model soundings
depict MUCAPE values greater than 2,000 J/Kg, mid-level lapse
rates of around 6.5- 7.0+ C/Km, cloud layer mean winds in excess
of 60 knots in addition to increasing DCAPE values of near, or
greater, than 900 J/Kg persisting across these areas into the
early nighttime hours Saturday night.

As such, the Storm Prediction Center (SPC)`s Day 2 Convective
Outlook highlights a Marginal (level 1/5) Risk for severe
thunderstorms across the Northern Ranchlands, the Upper Rio Grande
Valley and central/southern Zapata County within a 5% chance of
isolated severe wind gusts (at least 60 mph) and large hail.
Meanwhile, the northwestern tip of Zapata County is included within
a Slight (Level 2/5) Risk, where there is a 15% chance of large hail
in addition to the 5% chance of severe wind gusts. SPC further
mentions that a "...more intense supercell or two remains
plausible in...(the) Brush Country vicinity, capable of very large
hail..." which could potentially further increase the risk of
severe storms for Saturday evening. By Monday afternoon, we
currently expect generally one to three quarters of an inch of
rain across these areas, highest over northwestern portions of
Zapata County. The Weather Prediction Center keeps all risks of
flash flooding from excessive rainfall just north of our CWA
Saturday into Sunday, though this could change, depending on how
models trend over the next 24 hours. There is the potential for
several inches within the deepest convection and/or areas in which
showers and thunderstorms redevelop and persist as evident by the
HRRR and RAP.

Following, southwesterly flow aloft ahead of a cut-off low over the
Baja Peninsula, builds a mid/upper level high pressure over eastern
Mexico and subsidence northward, decreasing chances of rain
throughout Sunday to less than 10% by Monday morning as breezy to
windy conditions return from a tightened pressure gradient.
Increased clouds and rain likely keeps Sunday`s highs in the 80s,
possibly 70s over the Rio Grande Plains, before warming back to the
90s on Monday into Wednesday, with overnight low falling to the
60s/70s through Tuesday night. Unsettled weather is anticipated
again Tuesday into Wednesday as the cut-off low aloft and trough
move into central Texas. Global and long-term models indicate a
general weakening trend of the low, which would limit the severity
of convection, though still bares monitoring. As the system moves
north and east of our region, a cold front is expected to pass
through Deep South Texas on Wednesday, bringing breezy northerly
winds into the end of next week; fire conditions and concerns
increase as much drier air is advected southward into the CWA.
Temperatures could drop to near average for the first time in weeks
by the end of next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 1027 PM CST Fri Mar 6 2026

Southeasterly winds of around 10-15 knots, gusting to 20-25 knots,
and MVFR ceilings continue tonight across all terminals. VFR
conditions return by mid-morning as southeasterly winds increase
back to 15-20 knots, gusting to 25-30 knots. The approach of a
stalling frontal boundary has introduced PROB30s into the TAFs for
KMFE beginning Saturday evening, where this is the possibility of
strong to isolated severe thunderstorms, bringing damaging winds and
large hail. Low ceilings (IFR or lower) are likely at all terminals
Saturday night.

&&

.MARINE...
Issued at 1027 PM CST Fri Mar 6 2026

Moderate to fresh southeasterly winds and moderate (3-4 feet) seas
continue through Saturday afternoon. Winds become gentle to moderate
and chances of rain increase Saturday evening into Sunday to as much
as a medium to likely (40-70%) chance as showers and thunderstorms
develop along and ahead of a frontal boundary stalling near inland
Deep South Texas. A few storms may bring gusty winds and/or hail
Saturday night before transitioning to mostly rain showers on
Sunday. A pressure tightens again on Monday, leading to moderate
to fresh southeasterly winds and moderate seas into Tuesday.
Chances of rain increase again Tuesday into Wednesday to a low
(15-30%) chance, followed by a cold front on Wednesday, with
moderate northerly winds and moderate seas continuing into the end
of next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             72  87  72  86 /  10   0  30  50
HARLINGEN               69  91  69  87 /  10   0  40  60
MCALLEN                 74  94  73  89 /  10  10  50  80
RIO GRANDE CITY         71  97  67  82 /  10  10  70  90
SOUTH PADRE ISLAND      71  79  72  78 /  10   0  30  50
BAYVIEW/PORT ISABEL     69  86  69  84 /  10   0  30  50

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 6 AM CST Saturday for TXZ451-454-455.

GM...None.
&&

$$

SHORT TERM...65-Irish
LONG TERM....65-Irish
AVIATION...65-Irish