522
FXUS64 KBRO 062011
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
311 PM CDT Thu Jun 6 2024

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

.SHORT TERM...
(Tonight through Friday night)
Issued at 311 PM CDT Thu Jun 6 2024

Key Messages:

* The heat continues, but subtle relief arrives in terms of slightly
  drier air and lower late night/early morning temperatures

* Heat Risk also improves a little bit on Friday with more areas in
  Moderate (level 2 of 4) range

* Unhealthy air quality persists into at least Friday morning with
  some minor improvement by afternoon

* The surf finally becomes more favorable for more swimmers by
  Friday.

At long last...some modest relief in terms of apparent temperatures
is headed to the Valley and the ranchlands as nuanced dry air slides
in associated with the core of the upper level ridge which builds
across all of Texas and noses across all of south Texas. While
daytime temperatures will change little...humidity will drop by 10-
15 percent as afternoon dewpoints fall into the mid 60s (Brush
Country/Rio Grande Plains) to lower 70s (along/east of I69C/US 281)
which will keep apparent, or "feels like", temperatures in the more
"average" range of 103 to 108.  This means we break the four-day
streak of continuous advisories (and a few warnings) that began on
Monday.

The only minor item to consider this evening is a quick shot of
potential convection sliding in from the Sierra Madre...most likely
to impact southern Zapata through southern/central Starr County.
Confidence is not very high...but the GFS and some CAMs are hinting
at the possibility...and the Weather Prediction Center has
introduced a pocket of 0.05 to 0.4 inches of rain in these areas.
Not expecting anything severe...but one can never rule out small
hail and gusts to 40 mph in such a situation.  For now, have used 20
percent chances to cover the potential...only through 10 PM.

Otherwise...expect another round of yucky haze overnight into early
Friday as remaining pollutants are held in place by the inversion
and light to calm winds.  Air Quality rebounded (badly) to unhealthy
levels overnight through this afternoon...and would not be surprised
to see a short period of very unhealthy (index values 200 or a bit
higher) later tonight into mid morning Friday.

For Friday night...expect mainly clear skies with slightly higher
east southeast winds which may be enough to keep mentionable haze
out of the forecast. More importantly...for people looking for
overnight temperature "relief" they`ll finally get it as post-
midnight temperatures should fall below 80 just about
everywhere...with 70-73 likely by daybreak for all but urban centers
and the coast. Nobody will complain about these more seasonable
temperatures after so many mornings remaining at or above 80 in most
areas.

Finally...this afternoon remains tricky for beach goers as waves are
more inviting but the longshore continues to make swimming a bit
difficult. We`ve had a number of drownings/rescues on afternoons
like today (Thursday)...so vigilance is important.  By
Friday...waves recede and all currents should dip to low...allowing
decent swimming conditions for most compared with recent weeks.

&&

.LONG TERM...
(Saturday through next Thursday)
Issued at 311 PM CDT Thu Jun 6 2024

Key Messages:

*Above normal high and low temperatures
*Very low rain chances

The mid-level ridge continues to be the star of the weather for Deep
South Texas and the Rio Grande Valley. As such the middle and upper
levels of the atmosphere are expected to be dry and stable thanks to
the subsidence from the ridge. This will be a hindrance for any
showers and thunderstorms that try to develop. However, it is
possible that a rogue shower or thunderstorm could impact the region
around Monday or Tuesday, but confidence is not high at this time.

As for the heat, above normal temperatures will continue to persist
through the long term forecast period. However, the temperatures
will be slightly cooler than they have been with the the most recent
event. Even though there will still be plenty of humid air in the
region thanks to the southeasterly flow at the surface, Heat
Advisories are not likely to occur everyday. With the heat indices
under 111, Special Weather Statements are sufficient enough to cover
for them.

&&

.AVIATION...
(18Z TAFS)
Issued at 1243 PM CDT Thu Jun 6 2024

Persistent smoke/soot from the last of agricultural burning in
southeast Mexico...as well as Central American
wildfires...combined with increasing low level inversion(s) and
lighter winds associated with surface high pressure ridge
settling over the Valley have brought back visibility-reducing
haze/smog that was fairly thick this morning as pockets of IFR
visibility developed. That, along with potential for IFR
ceilings...is the primary concern for the overnight.

Persistence, therefore, is the best option for the overnight and
early Friday morning forecast. After the usual brief uptick in
easterly winds late this afternoon/early this evening, which
should keep haze at bay, expect haze to return as winds lay down
soon after sunrise. Despite a bit more easterly component aloft
(as well as across the smokier areas to our south), stagnant air
is still here (note another day of "Unhealthy" air quality) so
have lowered visibility to the edge of IFR (3 statute miles)
especially for the Lower Valley terminals, mainly after 1 AM.
Ceilings will form up as well but there is some uncertainty on the
duration of such...and exactly how low they drop to. High IFR/low
MVFR seems the best bet (900 to 1500 feet) which should continue
through 8 or 9 AM...then lift to high MVFR/low VFR to close out
the forecast window.

Winds will increase a little but still remain below 10 knots
through late morning. This should be enough to improve visibility
but not by too much...and would not surprise to see 6 miles
continue through lunchtime.

&&

.MARINE...
Issued at 311 PM CDT Thu Jun 6 2024

Tonight through Friday night...After many difficult boating days
dominated by persistent wind waves a chop...the arrival of surface
high pressure parking over the lower Texas Gulf waters will bring
much calmer conditions for this period.  Light east winds and slight
seas (falling to 2 feet) will be the rule through the period.

Tonight through Thursday Night...Light to moderate southeasterly
winds with moderate seas are expected to occur along the Lower Texas
Coast through Thursday Night as high pressure remains in control
over the Gulf of Mexico.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             80  96  79  95 /   0   0   0  10
HARLINGEN               76  97  75  96 /   0   0   0   0
MCALLEN                 79 100  77  99 /  10   0   0   0
RIO GRANDE CITY         78  99  75  98 /  20   0   0   0
SOUTH PADRE ISLAND      81  87  81  87 /   0   0   0  10
BAYVIEW/PORT ISABEL     79  91  78  91 /   0   0   0  10

&&

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

GM...None.
&&

$$

SHORT TERM...52-Goldsmith
LONG TERM....64-Katz
AVIATION...52-Goldsmith