Grulla, Texas Weather Forecast Discussion

822
FXUS64 KBRO 071122 AAA
AFDBRO
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
622 AM CDT Sun Sep 7 2025
...New AVIATION...
.DISCUSSION...
Issued at 1025 PM CDT Sat Sep 6 2025
The main focus for this forecast period continues to be the elevated
chances for rain continuing through the early part of next week.
Current model guidance does show that there is a large plume of
moisture that will make its way into Deep South Texas and the Rio
Grande Valley tomorrow. This will allow for PWATs to be around 2
inches through the early part of the week. The values of these PWATs
would be in the 90th percentile. Meanwhile, a frontal boundary is
expected to stall out to the north of the region. With southeasterly
to easterly flow on the surface, there will be plenty of low-level
moisture in the region to foster the development of showers and
thunderstorms over the region.
There are several factors to this rainfall event that bring a lot of
uncertainty to the forecast. Notably, how far south the front comes
down will be a major factor as the further south the front comes
down the greater chances for rain would be for the region. However,
if the front stays further north, the chances for rain could drop
for the area. Another factor will be how the seabreeze and any
outflow boundaries affect the development of showers and
thunderstorms. The interactions of the seabreeze and the outflow
boundaries are expected to be the main drivers for the development
of showers and thunderstorms with this event.  Given the amount of
uncertainty in the forecast, it is hard to say which locations are
likely to be impacted the most at this time. With so much
uncertainty in the forecast, a blend of the NBM, CONSALL, and ECMWF
were used to lower PoPs and to reduce some of the bias that is in
the NBM blends. Any sort of persistent rain over any area could lead
to some localized flooding especially for places in low-lying areas
and other flood prone regions. It should also be noted that given
the high amount of moisture in the environment, it is possible for
some of these showers and thunderstorms to produce a high amount of
rainfall in an area in a very short time, that could also lead to
some localized flooding as well. With all these factors combined,
WPC maintains a marginal risk (level 1 of 4) for excessive rainfall
for Deep South Texas and the Rio Grande Valley.
As for the temperatures in the forecast period, the highs for today
and tomorrow are expected to mostly be in the triple digits for the
region with areas along the coast could be in the upper 90s.
However, moving into the weekend and the rest of the forecast
period, temperatures are expected to decrease a bit due to the cloud
coverage over the area. Limiting the highs to mid to upper 90s for
the area. Low temperatures are expected to mostly remain in the 70s
for the forecast period as well.
&&
.AVIATION...
(12Z TAFS)
Issued at 618 AM CDT Sun Sep 7 2025
Only minor adjustments needed to the previous issuance of TAFs. A
TEMPO for convection remains based on the HRRR model guidance.
Overall, VFR is anticipated through the next 24 hours.
&&
.MARINE...
Issued at 1025 PM CDT Sat Sep 6 2025
Mostly favorable marine conditions are expected for the forecast
period with light to moderate southeasterly to easterly winds and
low to moderate seas. Showers and thunderstorms are expected to be
more likely through the early part of next week. A frontal boundary
is expected to stall out towards the north of the Lower Texas Coast.
Depending on how far north the front stalls out, will impact the
chances for rain.
&&
.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             91  78  90  77 /  60  60  60  40
HARLINGEN               92  74  92  73 /  70  60  70  30
MCALLEN                 94  77  93  76 /  70  70  60  20
RIO GRANDE CITY         93  74  93  73 /  70  70  60  20
SOUTH PADRE ISLAND      88  80  87  81 /  70  70  70  40
BAYVIEW/PORT ISABEL     90  77  90  76 /  70  70  60  30
&&
.BRO WATCHES/WARNINGS/ADVISORIES...None.
&&
$$

NWS BRO Office Area Forecast Discussion