-- Discussion containing changed information from previous version are highlighted. --
813
FXUS64 KBRO 201936
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
236 PM CDT Mon May 20 2024

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

.SHORT TERM...
-- Changed Discussion --
(Tonight through Tuesday night)
Issued at 236 PM CDT Mon May 20 2024

Key Messages:

- Above normal temperatures and heat index values are expected
  across Deep South Texas Tuesday afternoon.

- Heat index values will range from 105-114 degrees during the
  afternoon hours.

- Poor air quality will persist across portions of the region.

Hot and humid conditions will continue through the short term
period across Deep South Texas the region remains under the
influence of mid/upper level ridging and persistent low level
southerly to southeasterly flow. Stratus clouds will develop late
this evening from east to west, which will keep conditions mild
and humid tonight with low temperatures ranging from the mid 70s
across the Northern Ranchlands to low 80s across the Rio Grande
Valley. Some patchy fog may develop closer to day break, but
widespread dense fog is not expected. Morning cloud cover and fog
will quickly dissipate by mid morning, which will allow for
another warm day across Deep South Texas. Afternoon high
temperatures will range from the mid 80s along the Lower Texas
beaches to around 105 degrees across the Rio Grande Plains. In
combination with the humidity, "feels like" temperatures will
range from 105-114 degrees during the afternoon hours. Portions
of the Mid/Upper Rio Grand Valley and Northern Ranchlands may need
a Heat Advisory as heat indices rise above 111 degrees, but will
hold off on the issuance of any heat headlines with this update.
Otherwise, hazy skies associated with agricultural fires from
southeast Mexico will be an issue, with the haze more notable
closer to the coast.
-- End Changed Discussion --

&&

.LONG TERM...
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(Wednesday through next Monday)
Issued at 236 PM CDT Mon May 20 2024

Key Messages:

- Above normal temperatures and heat index values are expected
across Deep South Texas this week and Memorial Day weekend.

- The combination of above normal temperatures and humidity will
yield dangerous heat index values in the 110-120 degree range during
the day, and in the upper 80s to low 90s overnight.

- There will be an increased risk of heat related impacts,
especially those that do not take adequate breaks in the shade or
stay hydrated.

- Poor air quality will continue through the week for most of the
region.

The mid/upper level ridge centered over Mexico will limit any
precipitation chances across Deep South Texas. Meanwhile, established
low level southerly to southeasterly flow will maintain humid and
hazy conditions through the weekend and early next week. The haze
is associated with agricultural burning in southeast Mexico, which
will maintain periods of poor air quality across portions of the
region.

Well above normal temperatures will combine with high dew points,
which will result in dangerous heat index values each afternoon
across all of Deep South Texas. High temperatures will steadily
increase each day, with triple-digit high temperatures expected
along and west of I-69 by the end of the week, continuing into
Memorial Day weekend. In combination with the humidity, "feels like"
temperatures will range from 107-114 degrees Wednesday and Thursday
afternoons, and from 115-120 degrees Friday through Memorial Day.

To add to the oppressive daytime heat, nighttime temperatures
unfortunately will not provide much relief for most of the Rio
Grande Valley and portions of the Northern Ranchlands. Forecast
low temperatures in the low 80s are expected each night/early
morning, and in combination with the high humidity, will yield
morning "feels like" temperatures in the upper 80s and low 90s.
These very warm low temperatures and heat index values will limit
the ability for our bodies to recover from daytime heat.

Regardless of the issuance of Heat Advisories and/or Excessive
Heat Warnings (which are likely heading into Memorial Day
weekend), the prolonged period of excessive heat across all of
Deep South Texas will result in a major to extreme risk of heat
related impacts and illnesses to anyone who does not take the
necessary heat precautions. If you have any outdoor plans this
weekend, whether it`s to the beach, a graduation ceremony, or
outdoor get together, make sure you are taking the oppressive
heat into account.
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&&

.AVIATION...
(18Z TAFS)
Issued at 1254 PM CDT Mon May 20 2024

VFR will prevail through this evening across the region, with
intermittent periods of reduced visibility (around 5-6SM) due to
haze. MVFR ceilings will develop once again after 03Z and persist
through around 15-16Z Tuesday. Otherwise, expect south to
southeast winds around 10-15 knots today and tonight.

&&

.MARINE...
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Issued at 236 PM CDT Mon May 20 2024

Tonight through Tuesday night...Light to moderate winds and low to
moderate seas will prevail over the Gulf waters and Laguna Madre. Small
Craft Exercise Caution conditions will be possible for the Laguna
Madre and nearshore Gulf waters tomorrow afternoon as wind speeds
increase in response to a locally enhanced pressure gradient.

Wednesday through Monday...Small Craft Exercise Cautions
conditions will be possible across the Gulf waters and Laguna
Madre through the end of the week due to moderate winds and
building seas. Wave heights will approach 5-6 feet by Thursday
before slightly falling to around 4-5 feet into the weekend.
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&&

.PRELIMINARY POINT TEMPS/POPS...
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BROWNSVILLE             80  96  81  96 /   0   0   0   0
HARLINGEN               78  97  79  97 /   0   0   0   0
MCALLEN                 80 101  80 101 /   0   0   0   0
RIO GRANDE CITY         79 102  80 103 /   0   0   0   0
SOUTH PADRE ISLAND      81  87  82  87 /   0   0   0   0
BAYVIEW/PORT ISABEL     80  93  80  93 /   0   0   0   0
-- End Changed Discussion --

&&

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

$$

SHORT TERM...22-Garcia
LONG TERM....22-Garcia
AVIATION...22-Garcia