Brownsville, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

228
FXUS64 KBRO 182252
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
552 PM CDT Thu Jun 18 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 551 PM CDT Thu Jun 18 2026

* An Extreme Heat Warning is in effect today until 8 PM CDT. Heat
  indices exceeding 120 degrees are expected throughout Deep South
  Texas this afternoon and early evening.

* Little relief from the heat is expected tonight (heat indices are
  expected to remain above 90).  An Extreme Heat Watch is in effect
  tomorrow from 11 AM to 8 PM CDT.

* There is a low to moderate (20 to 40%) chance of showers and
  thunderstorms in the Western Ranchlands Friday and Saturday
  night. Low to moderate chances extend to all of Deep South
  Texas during the day on Saturday.

* A Moderate Risk of Rip Currents continues for area beaches through
  tomorrow afternoon.

* A Small Craft Advisory is in effect this afternoon through
  tomorrow morning.

&&

.DISCUSSION...
Issued at 1219 PM CDT Thu Jun 18 2026

An Extreme Heat Warning is in effect for all of Deep South Texas
(excepting the barrier islands) this afternoon and evening until 8
PM CDT. Heat indices of 120 or higher are possible for the entire
region today (excepting the islands), which are the highest heat
indices we have had since 2024. In addition, an Extreme Heat
Watch is also in effect for Friday as well, with little relief
from the heat expected overnight. The heat index is likely to stay
above 90 degrees overnight, and climb back up between 115 and 120
degrees tomorrow. Tomorrow`s Extreme Heat Watch may need to be
upgraded to a warning later this evening.

Moderate to Major Heat Risk concern will continue into the
weekend, and while heat indices will not be as high as today and
tomorrow, the heat index in some places could exceed 110 degrees
in some areas (especially in the Lower Rio Grande Valley) Saturday
through Monday. Additional Heat Advisories may be needed over the
weekend. Conditions should slightly improve on Tuesday, but the
heat index will still reach the triple digits. Actual
temperatures will lower from the upper 90s/lower 100s this weekend
to the mid-to-upper 90s by mid-week. However, the heat index is
more representative of how hot it is going to feel outside over
the next several days.

Conditions should be overall rain-free throughout the next week, but
a weak mid-level disturbance is expected to enhance the potential
for Sierra Madre convection to form in Mexico and move eastward into
our CWA starting Friday evening. The Western Ranchland Counties
could see some showers and thunderstorms (20 to 40% likelihood)
Friday night. These same low to moderate chances then spread
across Deep South Texas on Saturday before the Western Ranchlands
could see another round of Sierra Madre showers and thunderstorms
Saturday night as well. Flooding shouldn`t be too much of a
concern for most places, but an isolated flash flood cannot be
ruled out if an area that already received heavy rainfall earlier
this week also receives localized heavy rainfall this weekend.
Therefore, the Weather Prediction Center has included Deep South
Texas in a Marginal (level 1 of 4) Risk of excessive rainfall for
Saturday.

A moderate risk of life threatening rip currents remains in place
through tomorrow.

&&

.AVIATION...
(00Z TAFS)
Issued at 551 PM CDT Thu Jun 18 2026

Through 00z Saturday....VFR conditions, by and large, will prevail
through the 00z TAF cycle, though there could be a few MVFR clouds
around from time to time.

Additionally, we will have to monitor the potential for some MVFR
mist developing later tonight into Friday morning given the copious
amounts of low level moisture and the potential for narrowing
dewpoint depressions amid radiational cooling.

Winds will continue out of the south-southeast with speeds between
10-15 kts and gusts as high as 25-30 kts.

&&

.MARINE...
Issued at 1219 PM CDT Thu Jun 18 2026

A Small Craft Advisory is in effect for the Bay and Nearshore
Waters this afternoon through tomorrow morning due to elevated
wind gusts and seas. The Offshore Waters have a Small Craft
Advisory in effect until 12z tomorrow morning starting at 00z.
Intermittent periods of SCEC are possible this weekend through
early next week until conditions improve to more favorable by
midweek.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             84  96  84  94 /   0   0  10  20
HARLINGEN               81  97  81  94 /   0   0  10  20
MCALLEN                 83  98  83  95 /   0  10  20  40
RIO GRANDE CITY         81 100  80  95 /   0  20  30  30
SOUTH PADRE ISLAND      85  90  85  89 /   0   0  10  10
BAYVIEW/PORT ISABEL     83  94  83  92 /   0   0  10  20

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Extreme Heat Warning until 8 PM CDT this evening for TXZ248>255-
     351-353>355.

     Extreme Heat Watch from Friday morning through Friday evening
     for TXZ248>255-351-353>355.

GM...Small Craft Advisory until 7 AM CDT Friday for GMZ130-132-135-
     150-155.

     Small Craft Advisory until 7 AM CDT Friday for GMZ170-175.

&&

$$

SHORT TERM...55
LONG TERM....55
AVIATION...23-Evbuoma