Heat in Texas, May 20, 2024

Area Forecast Discussion
National Weather Service Brownsville TX
1254 PM CDT Mon May 20 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday)
Issued at 249 AM CDT Mon May 20 2024

500 mb high pressure will continue to build northeast out of
Mexico and increasingly be even more dominant over the BRO CWFA
during the period. This will have the effect of not only producing
dry weather, but also well above normal, and increasing, daytime
high temperatures. Heat index values will max out between 105 and
110 degrees today, with isolated spots reaching 111 degrees. Thus,
will not issue a Heat Advisory for today, but will instead cover
the heat threat with a Special Weather Statement. However, for
Tuesday, a Heat Advisory may very well be needed, with heat
indices progged to max out at 111 to 112 degrees across a more
widespread area. Will hold off on issuing a Heat Advisory for
Tuesday for now, and address the issue in about 24 hours (if not
less than that by a successive shift) after Monday highs are
tabled and new model guidance is available.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 249 AM CDT Mon May 20 2024

A broad 500 mb ridge centered over Mexico extending into Deep South
Texas and the Rio Grande Valley will maintain rain-free conditions
and above normal temperatures through the period. At the surface,
steady low-level southeasterly to southerly flow will result in
continued humid conditions across the area.

Dangerous heat will be the main concern through the week and into
Memorial Day Weekend as the mid to upper level ridge continues to
build. High temperatures are expected in the triple digits across
the Rio Grande Plains Wednesday afternoon with mid to upper 90s
across the rest of the area, except for the 80s along the coast. The
triple digit heat will expand farther eastward through the week,
reaching the I-69E/US 77 corridor by Friday. The high humidity
combined with the hot temperatures will lead to "feels like"
temperatures ranging from upper 90s along the beaches to around 112
degrees through Thursday, and closer to 114-118 degrees Friday
through the weekend, across the Northern Ranchlands and Rio Grande
Valley. Overnight temperatures will remain warm with lows in the
upper 70s to the lower 80s. The "feels like" temperatures each night
will remain in the upper 80s and low to mid 90s. Heat Advisories may
be needed for portions of the region Wednesday and Thursday, and
Heat Advisories and/or Excessive Heat Warnings will likely be needed
this Memorial Day weekend.

This will result in a major to extreme risk of heat-related impacts,
especially towards the end of the week and into the weekend. Staying
properly hydrated, limiting time spent outdoors during the peak
heating of the day, taking frequent breaks in the shade, and wearing
light-colored, loose-fitting clothing will be necessary to prevent
any heat related illnesses.

In addition, fair to poor air quality is expected to prevail through
the long term for much of the Rio Grande Valley due to agricultural
burning in southeast Mexico/Yucatan and Central American wildfires
all being driven north/northwestward on the persistent south to
southeast flow.

&&

.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...
Issued at 249 AM CDT Mon May 20 2024

Today through Tuesday: Buoy 42020 reported east-southeast winds
around 14 knots gusting to around 16 knots with seas slightly over
3.5 feet with a period of 7 seconds at 150 CDT/650 UTC. An
initially modest pressure gradient along the Lower Texas Coast
will strengthen slightly during the period, with high pressure
generally in control. Light to moderate winds and low to moderate
seas will become moderate to breezy winds and moderate seas during
the period, and Small Craft Should Exercise Caution may be needed
on Tuesday, especially for the Laguna Madre.

Tuesday night through Saturday...Light to moderate winds and
generally moderate seas are expected through the weekend. A locally
enhanced pressure gradient may result in a brief period of Small
Craft Exercise Caution conditions each afternoon on the Laguna Madre
and nearshore Gulf waters. Small Craft Exercise Caution conditions
will extend to the offshore Gulf waters Wednesday through the
holiday weekend due to increased winds and elevated seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             96  81  94  80 /   0   0   0   0
HARLINGEN               97  77  96  78 /  10   0   0   0
MCALLEN                101  80  98  80 /   0   0   0   0
RIO GRANDE CITY        101  78 101  78 /   0   0   0   0
SOUTH PADRE ISLAND      86  81  86  81 /  10   0   0   0
BAYVIEW/PORT ISABEL     91  79  92  79 /  10   0   0   0

&&

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

SHORT TERM...99
LONG TERM....99
AVIATION...22-Garcia