434
FXUS64 KBRO 161725 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1225 PM CDT Thu May 16 2024

...New AVIATION...

.SHORT TERM...
(Today through Friday)
Issued at 335 AM CDT Thu May 16 2024

This portion of the total forecast continues to be active.

First, a dryline will nudge into the western portion of the BRO CWFA
this afternoon and evening. While well above normal daytime high
temperatures are anticipated, felt NBM guidance was a few degrees
too warm, especially when compared to recorded highs from Wednesday
and additional model guidance. Thus, nudged NBM highs for today down
a couple of degrees, and when apparent temperature algorithm was
run, result is heat indices generally topped-out a smidge below
established Heat Advisory criteria (> or = to 111 degrees), with
very isolated pockets of heat indices at 111 degrees. Thus, will not
issue a Heat Advisory for any portion of Deep South Texas and the
Rio Grande Valley for today, but will instead cover the heat with a
Special Weather Statement. On a side note, Max Temperature and
Apparent Temperature consistency with neighboring WFO CRP, as of
this writing, looks good.

Finally, after tranquility tonight, the continued presence of the
dryline, the approach of a weak cold front, and a 500 mb shortwave
will produce a 20 to 30 percent chance of showers and thunderstorms
on Friday. The Storm Prediction Center places all of the BRO CWFA in
a general risk of thunderstorms, but with a Marginal Risk knocking
on the door as close as Baffin Bay, will have to remain vigilant and
watch for any strong to severe thunderstorms that may sneak into the
northern ranchlands, if not slightly farther south, for the end of
the work week. Additionally, will also have to watch for the
potential of a small-scale Heat Advisory, as heat indices in Cameron
County do indeed meet or exceed established Advisory criteria for a
couple of hours.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 335 AM CDT Thu May 16 2024

A very warm to hot pattern is expected to develop and persist
through the long-term forecast period (Friday night through Thursday
of next week). Global forecast models/ensembles continue to
advertise a strong 591-591 dam sub- tropical heat dome developing
over the region starting over the weekend and persisting through
next week.

With H850 temps expected to range between 22-26C, surface temperatures
are expected to be above average with daytime highs ranging from
the mid 90s to mid 100s, and overnight lows in the mid 70s to near
80F. Given the high humidity values, apparent "feel-like"
temperatures are expected to be elevated. Heat indices are
expected to range between 105-110F degrees over the weekend. Next
week, there could be instances of heat indices locally between
111-115F degrees.

That said, those without an effective cooling system and/or adequate
hydration will likely experience heat related impacts, according to
the NWS HeatRisk tool which is scoring widespread major to pockets
of extreme heat related impacts over the weekend and especially during
next week. Additionally, there is the chance the air quality will be
poor as well due to the type of airmass that will be in place.

With the strong sub-tropical heat dome in place over the region,
subsidence will allow for dry and tranquil weather conditions to
prevail.

&&

.AVIATION...
(18Z TAFS)
Issued at 1220 PM CDT Thu May 16 2024

Hazy conditions and low ceilings will persist through the TAF
period. MVFR conditions will prevail at BRO and MFE site though
this afternoon, with HRL visibilities remaining low with IFR.
Could see some brief periods of VFR this afternoon at BRO and MFE,
but only is visibility is able to improve at times. Tonight, HRL
could see a period of VFR returning as visibilities improve, but
early Friday morning IFR looks to return to HRL and BRO.

&&

.MARINE...
Issued at 335 AM CDT Thu May 16 2024

Today through Friday....Buoy 42020 reported southeast winds
around 16 knots gusting to around 21 knots with seas slightly
under 5 feet with a period of 6 seconds at 150 CDT/650 UTC.
Generally light to moderate winds and low to moderate seas will
prevail along the Lower Texas Coast through the period with high
pressure in control. However, the strength of the wind today may
be just enough to require Small Craft Should Exercise Caution,
mainly for the Laguna Madre and maybe the Gulf of Mexico waters
from 0 to 20 nautical miles offshore.

Friday night through Thursday...Light to moderate winds and
seas are expected to persist through the long-term period.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             93  80  96  79 /  10  10  20  10
HARLINGEN               96  77  97  76 /  10  10  20  10
MCALLEN                 98  80  98  78 /   0  10  20  10
RIO GRANDE CITY         98  78  98  77 /   0  10  20  10
SOUTH PADRE ISLAND      84  80  87  80 /  20  10  10  10
BAYVIEW/PORT ISABEL     91  79  93  78 /  10  10  20  10

&&

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

$$

SHORT TERM...99
LONG TERM....99
AVIATION...68-McGinnis