Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 260900
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
300 AM CST Mon Feb 26 2024

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

.SHORT TERM...
(Today through Tuesday)
Issued at 257 AM CST Mon Feb 26 2024

- Key Message: Windy and well above normal temperatures Tuesday.

Main weather element the next two day will be the wind especially
Tuesday as a surface low pressure area over the Plains States
deepens near 990mb. Pressure gradient strengthens today and more
substantially tonight and Tuesday with a Low Level Jet between 925-
850mb nearing 50 knots Tuesday morning. Model guidance is in good
agreement that a wind advisory will be needed Tuesday for the
coastal counties (Cameron, Willacy, Kenedy) and  possibly over the
eastern portions of the Hidalgo county. Probability of wind gusts of
40-45 mph is high (70-90%) for much of Cameron County with a medium
chance (50-60%) across Willacy, Kenedy and eastern portions of
Hidalgo Counties.

Otherwise, 500mb ridge axis continues over North Mexico/South Texas
keeping our atmosphere rather dry even with the south winds
increasing the next few days. Subsidence keeps skies mostly clear
with warmer than normal temperatures. Highs will be 5 to 8 degrees
above normal today and possibly 8 to 12 degrees above normal Tuesday
as the  subsidence or compressional heating increases in advance of
a Wednesday cold front. We can expect maximums in the 80s to lower
90s today and upper 80s to mid 90s Tuesday. 850mb temperatures
around 25C support the warm to hot temperatures Tuesday.  Overnight
lows will also be warmer than normal as well due to the stout
southerly flow allowing for higher dew points and limiting
radiational cooling.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 257 AM CST Mon Feb 26 2024

A 500mb low swings into the Plains into Wednesday, with a Baja
low eventually following suit by Thursday, maintaining generally
southwesterly flow aloft through the week, before more zonal flow
arrives for the weekend. At the surface, a strong cold front
arrives on Wednesday, pushing through the northern ranchlands near
daybreak and working through the RGV into the early afternoon.
The better surge of high pressure and CAA arrives late afternoon
into early evening, with breezy northerly winds. A coastal low
sets up and holds the frontal boundary just beyond the coastal
waters through the weekend, potentially leading to a few offshore
showers Thursday into Saturday.

Have once again worked with neighboring offices to nudge
temperatures below the NBM for Wednesday afternoon and early
night, utilizing the NBM25 and CONSMOS guidance. For what it’s
worth, NAM guidance remains cooler yet by 5 degrees or so.
Confidence is a little lower for highs across the lower to mid RGV
Wednesday, with any slower push from the front resulting in warmer
highs. Have kept everyone into the low 80s for now. Thursday’s
highs only reach the mid to upper 60s for most, with a gradual
warming trend from there, back into the 70s Friday, and 80s for
the weekend, with a few 90s possible on Sunday across mainly
Zapata and Starr counties.

Relative humidity drops behind the front on Wednesday, but begins
to recover near the same time northerly 20 foot winds speeds reach
15 mph. At this time, any Fire Danger criteria appears to be
short-lived or just misaligned with the stronger winds and lower
humidity.

&&

.AVIATION...
(06Z TAFS)
Issued at 944 PM CST Sun Feb 25 2024

Through 06z Tuesday....VFR conditions are taking place at all of the
terminals with high pressure overhead and mid-level ridging just
upstream. The main weather concern will be during the overnight
period. The MET MOS and NBM MOS guidances continue to suggest the
potential for some mist/fog developing during the overnight hours,
particularly closer to daybreak. With mainly clear skies overhead
giving way to adequate radiational cooling, mist/fog development
will be dependent on how strong or light the winds become.

The best chance for mist/fog development will be over the interior
locations (i.e. Ranchlands). That`s where DESI has a moderate (30-
60%) chance for mist/fog developing tonight. Have opted to leave
mist/fog out of the TAF sites as it appears that winds will remain a
factor along the Rio Grande Valley tonight. VFR conditions continue
during the day on Monday. However, forecast models are indicating
the potential for MVFR cigs developing Monday evening/night.

South-southeast winds 10-20 kts with gusts between 25-30 kts will
wane this evening into tonight slightly before strengthening again
during the day on Monday.

&&

.MARINE...
Issued at 257 AM CST Mon Feb 26 2024

Today through Tuesday...Pressure gradient steadily tightens today
through Tuesday morning as low pressure over the Central and high
pressure deepens. Fresh winds today become strong late this
afternoon and tonight with Small Craft advisories first over the
Laguna Madre before sunset spreading offshore tonight. The strong
gradient persist Tuesday with SCAs likely to be extended. Seas start
off moderate building tonight and Tuesday.

Tuesday Night through Sunday...Any ongoing Small Craft Advisories
or hazardous marine conditions are expected to gradually improve
Tuesday night into early Wednesday. A cold front arrives with a
surge of strong northerly winds by Wednesday afternoon into
Wednesday evening, driving additional adverse conditions into
Thursday evening. Lighter northerly winds eventually turn
southeasterly this weekend, with marine conditions gradually
improving Thursday night into Sunday. The chance of showers
returns, generally offshore Thursday through Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             81  68  85  68 /   0   0   0   0
HARLINGEN               86  65  89  65 /   0   0   0   0
MCALLEN                 89  66  93  66 /   0   0   0   0
RIO GRANDE CITY         91  65  96  65 /   0   0   0   0
SOUTH PADRE ISLAND      73  67  76  67 /   0   0   0   0
BAYVIEW/PORT ISABEL     80  65  83  65 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory from 4 PM this afternoon to midnight CST
     tonight for GMZ130-132-135.

     Small Craft Advisory from 9 PM this evening to 6 AM CST Tuesday
     for GMZ150-155-170-175.

&&

$$

SHORT TERM...59-GB
LONG TERM....56-Hallman
AVIATION...59-GB


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