533
FXUS64 KBRO 011150 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
650 AM CDT Sat Nov 1 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 623 AM CDT Sat Nov 1 2025

 - Above average temperatures are expected today as warm air advection
   results from south-southeasterly winds ahead of an advancing
   cold front.

 - Isolated to scattered showers and thunderstorms are expected to
   develop ahead of the cold front throughout the late evening and
   late night hours tonight, rising probabilities of rain to a
   medium to likely (40-70%) chance across the eastern half of
   Deep South Texas.

 - The Storm Prediction Center (SPC) has outlined a Marginal
   (level 1 of 4) Risk, mainly along and east of US-281/I-69 C,
   for the possibility of isolated severe thunderstorms along the
   leading edge of convection, capable of producing large hail and
   damaging wind.

 - A medium, possibly high, risk for rip currents is likely Sunday
   into Monday due to the increase in wind, wave heights and wave
   periods following the front as well as from the building
   influence of astronomical tides.

&&

.DISCUSSION...
Issued at 1047 PM CDT Fri Oct 31 2025

Throughout the day today, a mid-level shortwave trough axis and
surface cold front will swing southeastward from New Mexico/northern
and western Texas this morning into Deep South Texas throughout the
evening and nighttime hours tonight. As winds turn from south-
southeasterly to east-southeasterly this afternoon, moisture pooling
ahead of the front may bring a low (15-20%) chance of rain across
Willacy and Kenedy counties along the seabreeze boundary. As the
front and trough approach closer late this evening, enhanced
forcing and lift are expected to increase probabilities of rain to
a low to medium (20-40%) chance as far west as eastern portions
of Jim Hogg and Starr counties, while also increasing to a medium
to likely (40-70%) chance east of US-281/I-69 C, with the greatest
chance along the immediate coastline. SPC has outlined a Marginal
(level 1 of 5) Risk for isolated severe thunderstorms along the
leading edge of convection for locations near and east of
US-281/I-69 C, with the primary threat of large hail and damaging
wind in addition to brief periods of heavy rain. The NBM and CAM
guidance are in fair agreement that the time window for isolated
thunderstorms is between late this evening and late tonight.
However, there is a possibility that the trough and cold front
could move faster than anticipated, which could result in an
earlier arrival of strong to severe thunderstorms, such as
potentially the late afternoon/early evening hours. Following,
there is a low to medium (30-60%) chance of additional rain from
showers and thunderstorms overnight closer to the coast, which is
expected to diminish in coverage and probability into the pre-dawn
hours on Sunday as the front passes through all of Deep South
Texas.

Ridging aloft returns throughout Sunday, resulting in dry conditions
(less than 10% PoPs) into next week. North-northeasterly winds on
Sunday gradually veer from north-northeasterly on Sunday to easterly
on Monday before becoming southeasterly by Tuesday as the surface
high pressure over the Southern Plains moves east into the Midwest
and Mid-Atlantic regions.

Warm air advection ahead of the front today and then the passage of
the front tonight is expected to drop high temperatures from above
average, with upper 80`s to lower 90`s inland and lower 80`s at the
coast during the day today to slightly below/near average Sunday
into Tuesday, with 80`s inland and 70`s along the coast. Yet, due to
increased subsidence aloft, plentiful sunshine and winds veering to
southeasterly by midweek, a gradual warming trend will push
temperatures back to above average by Wednesday and into the later
part of the week. Morning lows are expected to be at their coolest
of the forecast Monday morning with lows mainly in the 40`s (in the
northern ranchlands) and 50`s elsewhere before rising to near
average by Tuesday morning with 50`s and 60`s.

Additionally, a low risk of rip currents continues through the
daytime today, likely continuing into tonight. In the wake of the
cold front, a medium, possibly even high, risk is likely Sunday into
Monday as winds, wave heights and wave periods increase in
combination with increasing effects of astronomical tides on Monday.

&&

.AVIATION...
(12Z TAFS)
Issued at 623 AM CDT Sat Nov 1 2025

VFR conditions to prevail most of Saturday before a cold front
approaches South Texas this evening. Light and variable winds this
morning become gusty, around 20 kts, prevailing south-
southeasterly through the morning and afternoon.

Tonight, the approaching cold front will bring a wind shift from
the north and increase chances of rain and thunderstorms. There is
a chance of isolated severe convection, with higher probabilities
along the coast. Timing and coverage is too uncertain at present
to use prevailing TS/VCTS, but convection is possible as early as
00Z continuing through as late as the end of the 12Z cycle. Most
likely times are denoted by PROB30s at each site. Any showers and
storms passing over a site may bring lightning and IFR conditions
through low ceilings and reduced visibility. Severe storms may
bring strong winds and large (an inch or greater) hail.

&&

.MARINE...
Issued at 1047 PM CDT Fri Oct 31 2025

Southerly gentle to moderate winds, accompanied by slight (1-2 ft)
seas, today are expected to become north-northeasterly tonight as a
cold front passes through. This will increase probabilities of rain
to a medium to likely (40-80%) chance this evening and tonight as
isolated to scattered showers and thunderstorms develop ahead of the
front, with the possibility isolated severe thunderstorms capable of
producing large hail and damaging winds in addition to brief periods
of heavy rain. Small Craft Exercise Caution and/or Small Craft
Advisory conditions are also expected late tonight into Sunday
afternoon as a surface high pressure enhances winds to fresh,
perhaps occasionally strong, in the wake of the frontal passage,
resulting in moderate (3-5 ft) seas. Winds and chances of rain
gradually diminish throughout Sunday with gentle to moderate
easterly winds and slight to moderate (2-3 ft) seas returning Monday,
becoming southeasterly with slight (1-2 ft) seas by Tuesday. Dry
conditions return for the rest of the period by Sunday afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             87  66  79  58 /  10  60  20   0
HARLINGEN               88  60  80  52 /  10  50  10   0
MCALLEN                 91  62  82  55 /  10  30  10   0
RIO GRANDE CITY         91  58  82  51 /   0  20   0   0
SOUTH PADRE ISLAND      82  71  77  69 /  10  70  20   0
BAYVIEW/PORT ISABEL     86  65  78  59 /  10  70  20   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory from 1 AM to noon CDT Sunday for GMZ130-132-
     135-150-155-170-175.

&&

$$

SHORT TERM...65-Irish
LONG TERM....65-Irish
AVIATION...69-HK