707
FXUS64 KBRO 060900
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
400 AM CDT Thu Jun 6 2024

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

.SHORT TERM...
(Today through Friday)
Issued at 332 AM CDT Thu Jun 6 2024

Key Messages:

* Continued Hot Today and Friday with Record to Near Record-Breaking
  Temperatures Developing This Afternoon

* Heat Advisory in effect from 1PM-8PM CDT today for All of Deep
  South Texas and the Rio Grande Valley with the exception of the
  island counties

* Major HeatRisk continues

* Marine Conditions become More Favorable Tonight into Friday along
  with Very Low Rain Chances

The main weather headline through the short term forecast period
will continue to be the heat. According to the latest large-scale
500 mb upper air analysis, the local forecast area is on the eastern
edge a heatwave taking place over the western U.S. as a massive and
anomalously strong 591 dam heat dome is situated over the Desert
Southwest. Deterministic forecast models/ensembles show this heat
dome shifting eastward over Texas on Friday, however, in a somewhat
weaker state as the heatwave/500 mb pattern out West breaks down
slightly thanks to periods of shortwave energies/impulses helping to
compromise the pattern a bit.

That said, strong differential surface heating with a strong ridge
overhead will increase dewpoint depression and allow for any low
level clouds to scour out by this afternoon. With 850 mb
temperatures sampled between 23-26C, 1.5 to 2.5 STDEVs above normal,
sfc temperatures will have no trouble climbing once again into the
upper 90s to lower 100s across Deep South Texas and the Rio Grande
Valley this afternoon. Marry this with dewpoint (Td) temperatures in
the mid to upper 70s, and heat indices will range from 109-116F this
today. Given the situation, a Heat Advisory has been issued for all
of Deep South Texas and the Rio Grande Valley with the exception of
the island counties of Cameron, Willacy, and Kenedy from 1PM-8PM CDT
today. Inland Cameron, Willacy, Kenedy, Counties along with Brooks,
Hidalgo, and Starr Counties are areas that are expected to see the
highest heat indices. Lastly, the expected high temperatures later
this afternoon are expected to be record or near record-breaking.
Brownsville and Harlingen have the best chances for either tying or
setting a new record today (see Climate Section below).

Tonight will feature another warm and muggy night with overnight low
temperatures in the mid 70s to near 80F degrees. Narrowing dewpoint
depressions given the copious amounts of low level moisture tonight,
will allow for low level clouds to increase in coverage once
again.

Friday will feature another very warm to hot day, though not as hot
as today given that the aforementioned heat dome/500 mb pattern
weakens some (as highlighted above earlier). Humidity levels are not
expected to be as strong as today neither. That said, max heat
indices will be weaker on Friday than today with values ranging from
103-111F.

&&

.LONG TERM...
(Friday Night through Wednesday)
Issued at 332 AM CDT Thu Jun 6 2024

The center of broad 500 mb high pressure will migrate from the
Lone Star State, to the north-central Gulf of Mexico, and then to
northwest Mexico, but will remain the dominant weather feature
over the BRO CWFA. Although dry weather will prevail through a
majority of the period, isolated convection is possible Monday and
Tuesday, but confidence in this occurring is not high at this time.

Temperature-wise, well above normal daytime highs will continue to
be the norm. However, slightly cooler values, when compared to
recent trends, will result in a HEAT ADVISORY not anticipated each
day, with heat indices more likely to be discussed in a daily SPECIAL
WEATHER STATEMENT.

&&

.AVIATION...
(06Z TAFS)
Issued at 1219 AM CDT Thu Jun 6 2024

Through 06z Friday....A BKN-OVC strato-cu deck of MVFR ceilings with
cloud bases between 1,500-2,000 feet AGL with unrestricted
visibilities are taking place at the terminals. For the duration
of the overnight into Thursday morning, expect for MVFR ceilings
to persist. Late this morning or early this afternoon, expect for
both cloud coverage and cloud heights to improve back to VFR and
persist through the remainder of today.

Southeast winds 5-10 kts will persist through the entirety of the
06z TAF cycle.

&&

.MARINE...
(Today through Friday)
Issued at 332 AM CDT Thu Jun 6 2024

With the aforementioned 591 dam sub-tropical ridge moving
overhead, marine conditions are expected to become more favorable
tonight and Friday. Light to moderate winds and seas today will
give way to light seas tonight into Friday. A moderate risk for
rip currents is expected today. However, the risk becomes a low
risk for rip currents tonight and on Friday.

(Friday Night through Wednesday)
Light to moderate winds and low to moderate seas will occur along
the Lower Texas Coast through the period with high pressure in
control over the western Gulf of Mexico. Neither Small Craft
Should Exercise Caution nor Small Craft Advisory are anticipated
to be needed.

&&

.CLIMATE...
Issued at 332 AM CDT Thu Jun 6 2024

Record Highs for today June 6, 2024

Brownsville 98F in 2018 (Forecast High is 99F)
Harlingen 100F in 2019 (Forecast High is 100F)
McAllen 103F in 2018 (Forecast High is 101F)

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             98  79  97  79 /  10   0  10   0
HARLINGEN              100  76  99  75 /  10   0  10   0
MCALLEN                101  79 101  78 /  20   0  10   0
RIO GRANDE CITY        100  78 101  76 /  10  10   0   0
SOUTH PADRE ISLAND      88  81  88  81 /  10   0  10  10
BAYVIEW/PORT ISABEL     94  79  93  78 /  10   0  10   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 1 PM this afternoon to 8 PM CDT this evening
     for TXZ248>255-351-353>355.

GM...None.
&&

$$

SHORT TERM...Evbuoma-23
LONG TERM/UPPER AIR...Tomaselli-66