Area Forecast Discussion
Issued by NWS Brownsville, TX

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
000
FXUS64 KBRO 291130 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
630 AM CDT Fri Mar 29 2024

...New AVIATION...

.SHORT TERM...
(Today through Saturday)
Issued at 413 AM CDT Fri Mar 29 2024

A flat mid-level ridge with a nearly zonal flow aloft will prevail
over Deep South Texas leading to dry and tranquil conditions through
the short-term. The only concern today will be the winds. Light to
moderate southeast winds early this morning are expected to increase
later this morning and becoming breezy by the afternoon. A low level
jet with winds between 30 to 35 knots is expected over the area
today. Used a mix of the previous winds, NBM operational, and
CONSMOS for winds through Saturday. Wind gusts are forecast to range
between 30 and 35 mph across much of the area. The DESI NBM
probabilities indicate a small portion of the Lower Valley of 20 to
30 percent of wind gusts of 40 mph or higher for today. Therefore,
confidence remains low for issuing an Wind Advisory for today.

Otherwise, a continued warming trend is expected due to the steady
onshore flow. Highs today will be in the 80s, except for the 70s at
the beaches. Mild tonight with lows in the mid to upper 60s. Very
warm on Saturday with highs in the 80s, a few 90s will be possible
across the Rio Grande Plains.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 413 AM CDT Fri Mar 29 2024

Key Messages:

- Becoming Windy Sunday-Monday (southerly winds 20-30 mph with
higher gusts)

- Very Warm to Hot Sunday-Monday (widespread 90s and 100s)

Changeable weather pattern during the long-term forecast period
featuring a big warm up and windy conditions at the beginning of the
period to temperatures returning closer to normal levels during the
second half of the period.

We start off the long-term period Saturday night where aloft the 500
mb setup will feature an amplified pattern with an anomalously
strong low/trough over the Southwestern CONUS and a resultant
downstream ridge over the southern and eastern two-thirds of the
CONUS with the ridge axis placed over the Gulf Coast states.

Saturday night into Sunday, a surface pressure gradient is expected
to intensify over the region with a surface lows over the southern High
Plains and at times north central Mexico interacting with a
surface high over the Gulf of Mexico. Forecast models are
indicating H850 (low level jet) winds intensifying over the region
Sunday afternoon and persisting into Monday. Low level jet winds
during this timeframe were sampled between 35-45 kts over the
region with the strongest of winds east of I-69. All of this
coupled with increased mixing heights Sunday afternoon through
Monday will result in breezy to windy conditions Sunday and Monday
with southerly winds at the surface sustained between 20-30 mph
and gusting up to 40 mph. Wind Advisories may be needed
considering the strong winds aloft and the local/climate effects
over the Rio Grande Valley (can see wind gusts being higher than
40 mph Sunday and/or Monday). Will have to keep monitoring trends
in the days ahead.

A strong return flow in the lower levels out of the south will
result in adequate warm air advection during the day on Sunday and
Monday. On Monday, 850 mb winds are expected to switch out of the
west. Enhancements due to compressional heating with air moving down
the slopes of the Sierra Madre Oriental could result in a heat spike
over the region on Monday. That said, current thinking is that
daytime highs will get into the upper 80s to near 100F degrees over
Deep South Texas with the hottest temps over the western parts of
the area. On Monday, daytime highs are projected to be even warmer
with values in the 90s to 100s (hottest readings or widespread
triple digit readings once again over the western half of the area).

On Tuesday, forecast models and ensembles show the large scale
pattern breaking down (i.e. becoming less amplified with troughing
over the western U.S. translating eastward. Near the surface a cold
frontal boundary is expected to pass over the area on Tuesday. Still
some uncertainty as to the exact timing of the frontal boundary.
However, consensus shows that temperatures will have enough time to
warm into mid/upper 80s to near 90F across the area before passing
through. The cold front will be moisture starved, so no precipitation
is expected.

Following the cold fropa, a welcomed drier and cooler airmass will
take hold over the area. Tuesday night, overnight low temperatures
are progged to be in the upper 50s to lower 60s (a notable relief
for residence of Deep South Texas and the Rio Grande Valley). With a
full dry and cool air advection regime in place, Wednesday will be a
pleasant day with highs only reaching the upper 70s to lower 80s.
Thursday and Friday will be slightly warmer and closer to normal
with highs in the low to mid 80s.

&&

.AVIATION...
(12Z TAFS)
Issued at 629 AM CDT Fri Mar 29 2024

Clear skies and generally light southeast winds prevail across
Deep South Texas early this morning. Winds are expected to
increase mid to late morning in response to a strengthening
pressure gradient. Sustained winds around 20-25 knots with gusts
around 30-35 knots will prevail through this evening. Winds are
expected to decrease by late in the period.

&&

.MARINE...
Issued at 413 AM CDT Fri Mar 29 2024

Now through Saturday...Adverse conditions will develop along
portions of the Lower Texas Coast this morning. A Small Craft
Advisory remains in effect for the Laguna Madre beginning at 16Z
until 01Z Saturday due to the strengthening southeasterly gradient
flow. The latest DESI supports higher wind probabilities over the
nearshore Gulf waters. Therefore, have issued a Small Craft Advisory
for the nearshore GUlf waters (0-20 nm during this same timeframe as
the Laguna Madre (16z until 01Z). Exercise Caution conditions will
prevail across the remainder of the coastal waters today and across
the waters tonight and Saturday. Seas will continue to slowly
respond and build to 4-6 feet by tonight due to the moderate to
occasionally strong southeast flow.

Saturday Night through Friday....Persistent high pressure in place
over the Gulf interacting with low pressure systems over the
southern High Plains, and to some extent lower pressures over
North Central Mexico, will keep a tighter pressure gradient in
place over the Lower Texas coastal waters through Monday. A cold
front will move through on Tuesday and will shift winds to
northwest as high pressure spreads across the region. Moderate to
fresh southeast to south winds and moderate to high seas will be
the rule most of the early long term. Moderate to fresh winds will
carry over from Friday night into Saturday and will persist all
the way through Monday. A cold front will push through late Monday
or early Tuesday, bringing moderate to fresh northwest to north
winds. Overall, small craft should exercise caution conditions
will be common to continuous through the period. Low end small
craft advisory conditions may additionally develop from time to
time due to enhanced winds and/or seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             80  68  81  71 /   0   0   0   0
HARLINGEN               82  64  84  69 /   0   0   0   0
MCALLEN                 85  67  87  70 /   0   0   0   0
RIO GRANDE CITY         86  64  90  68 /   0   0   0   0
SOUTH PADRE ISLAND      74  69  75  70 /   0   0   0   0
BAYVIEW/PORT ISABEL     79  66  80  69 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory from 11 AM this morning to 8 PM CDT this
     evening for GMZ130-132-135-150-155.

&&

$$

SHORT TERM...63-KC
LONG TERM....23-Evbuoma
AVIATION...63-KC


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.