694
FXUS64 KBRO 092004
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
304 PM CDT Sun Jun 9 2024

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

.SHORT TERM...
(Tonight through Monday night)
Issued at 305 PM CDT Sun Jun 9 2024

Key messages:
* Closer to seasonal temperatures return...though still closer to
  late June than mid June

* Sea breeze should produce isolated to scattered showers and a
  possible thunderstorm Monday but not enough rain to dent soil
  moisture deficits

* Great weather for the beach when combining low waves and
  currents with warm surf and cleaner air

Believe it or not...a little bit of "normal" June weather returns
to begin the work week. While temperatures will remain a couple
degrees above average tonight and Monday, the low level pattern
returns to a more summer-like east to east-northeast flow...albeit
light...by Monday afternoon. The 500 mb pattern continues to
feature a La Caninula-like ridge, but its intensity is more in
line with what we`d expect in early to mid June. At the same
time...deep layer moisture continues to creep upward and blended
model precipitable water values reach to or just above 2 inches.
That means the low level onshore flow combined with the moisture
should be enough to kick off a day of isolated to scattered sea
breeze showers and a few storms. With limited forcing, however,
not expecting prolonged rainfall or any notable impact to the
dryness/parched soil moisture condition...but a little rain along
with more azure blue skies is quite the welcome site after so many
weeks of polluted haze and smoke (which had begun to recede
gradually after the start of June).

In terms of sensible weather...the only other concern is whether
any upstream convection...courtesy of weak energy rotating around
the front side of the aforementioned ridge...can reach the
northern ranchlands and Rio Grande Plains this evening. Model
blends are bearish but deterministic model (i.e. GFS) is a bit
more bullish. For now, have left mentionable rain out of the
forecast but will need to keep eye on radar for potential between
7 PM and midnight. Otherwise, another sultry night as evening
southeast winds drop overnight but remain at or above 5 mph which
should keep lows around 80 for the populated RGV and upper 70s
elsewhere.

For Monday, the light morning southeast winds will back easterly
around noon, and with aforementioned moisture uptick expect
isolated sea breeze convection to develop just inland from the
coast between 11 AM and noon. Convection likely to start sooner in
the Gulf and could sneak onto the barrier island before 11
AM...but typically we see convection "jump" west and miss the
resort areas completely. Blended forecast catches this by 4
PM...but likely to see the beaches cleared out (except for
offshore towers) by 1 PM or sooner.

Inland...sea breeze should kick off disorganized isolated to
scattered showers and a few thunderstorms, peaking between 2 and
5 PM as they nose westward into the mid/upper Valley. High
temperatures may be briefly impacted by the rain or nearby
boundaries...but typically we see highs near average in such a
situation (especiallly the first of the summer) so blended values
of 94 to 98 for most looks on target.

Convection should end by late afternoon, perhaps early evening
across the Rio Grande Plains, followed by clearing skies and
temperatures falling a few degrees lower than tonight based on
near calm late night winds. Precipitation type grids have put
patchy to areas of fog...visibility probably in the 1 to 3 mile
range toward daybreak Tuesday...and this seems reasonable given
the slightly lower temperatures and near calm wind.

&&

.LONG TERM...
(Tuesday through next Sunday)
Issued at 305 PM CDT Sun Jun 9 2024

Much of the forecast will be dominated by mostly sunny/clear skies
and light to moderate breezes. Mid-level ridging to the west will be
in control Tuesday. A short-wave trough/mid-level low over northeast
Texas will edge east Tuesday night, but not before sending a burst
of energy south toward Central Texas and the Coastal Plains.
Currently, the energy looks like it will dissipate before
significantly impacting the RG Plains and/or the Upper Valley of
deep South Texas.

Heading into mid-week, mid-level ridging over the Southwest United
States will build, with high pressure over the lower Mississippi
Valley extending over the Northwest Gulf. A broad upper trough will
lie roughly over the same area, destabilizing the West Gulf of
Mexico and supporting a seasonal increase in shower activity. The
ECMWF envisions sea breeze events Tuesday through Friday, with pops
in the grids being slightly more robust on Tuesday.

In the meantime, later this week, the ridging over the Southwest
U.S. will break down and shift east over portions of Texas. It will
be replaced upstream by a filling cutoff low lifting into the
Central High Plains. Rump ridging will remain across North Mexico
and along the Texas portion of the Rio Grande, however. The main
impact for next weekend, then, may only be a better chance of Gulf
showers affecting mainly the middle and upper Texas Coast.

The main hazard of concern in the long term, heat, will remain
restrained from extreme values. Still, overall temperatures will
continue to run a few degrees warmer than normal for this time of
year. The NBM advertises low temperatures generally in the mid to
upper 70s. High temperatures may poke above the century mark out
west each afternoon, but most areas will be looking at mid to upper
90s. Only next Sunday, at the end of the period, will high temps
creep a few degrees higher and flag a possible low end heat
advisory.

&&

.AVIATION...
(18Z TAFS)
Issued at 305 PM CDT Sun Jun 9 2024

Overall...same forecast (from Saturday) but different day. Few to
scattered VFR cumulus this afternoon at the lower Valley terminals
with any low clouds clearing out at McAllen by mid afternoon.
We`ll also see the usual east to west movement of the enhanced
southeast flow with gusts around 20-22 knots at Brownsville and
Harlingen through sunset...and 24 knots at McAllen just before
sunset for a couple hours after.

For the overnight...other than scattered MVFR fractus
clouds...we`ll need to keep an eye on any residual mid/high
clouds from any convection that develops in central/south central
Texas as weak short wave energy rotates through the general upper
level ridging overnight. Not expecting any of this convection or
residual rain and lower clouds to reach the Valley terminals at
this point. Quick develop scattered-broken low VFR cumulus again
Monday morning with slightly lower southeast wind speeds.

&&

.MARINE...
Issued at 305 PM CDT Sun Jun 9 2024

Tonight through Monday night...A continued easing of winds and
seas through the period as the surface ridge expands back west
across the waters. Seas were just below 3 feet this afternoon but
should fall to 2 feet across the waters tonight and remain through
Monday night. Southeast winds will gradually drop below 10 knots
later tonight, then back to the east at 10 knots or less Monday
and continue through Monday night. As for rain...expect isolated
to scattered showers and perhaps a thunderstorm to begin later
tonight and continue through Monday early afternoon before fading
as is typical with sea breeze inland shifts...then resume but
isolated at most Monday night.

Tuesday through Friday night...A weak pressure gradient will support
light to moderate east to southeast winds and low to moderate seas
through the forecast. In this summer regime, marine convection will
become more active, resulting in periodic isolated to scattered Gulf
showers.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             82  96  79  95 /   0  20  10  30
HARLINGEN               78  96  76  97 /   0  30  10  20
MCALLEN                 81  98  79  99 /   0  30  20  20
RIO GRANDE CITY         80  97  78  98 /  10  20  30  10
SOUTH PADRE ISLAND      83  88  81  87 /  10  30  10  30
BAYVIEW/PORT ISABEL     80  93  79  92 /   0  30  10  30

&&

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

$$

SHORT TERM...52-Goldsmith
LONG TERM....54-BHM
AVIATION...99