079
FXUS64 KBRO 011720
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1220 PM CDT Tue Oct 1 2024

...New AVIATION...

.SHORT TERM...
(Today through Wednesday)
Issued at 257 AM CDT Tue Oct 1 2024

Slightly above normal temperatures will continue through the period
as weak mid level ridging builds over Deep South Texas. Light and
variable winds may allow for some patchy fog to develop early this
morning, but any fog that forms should quickly dissipate shortly
after sunrise.

High temperatures today and Wednesday will be in the low to mid 90s.
The limited precipitable water values should maintain comfortable
conditions with heat indices mostly in the upper 90s. Low
temperatures tonight will range from the upper 60s across the
Northern Ranchlands to lower 70s across the Rio Grande Valley.

No rain is expected today. As low level moisture starts to gradually
increase tonight, isolated to scattered showers may develop off the
Lower Texas coast. Isolated to scattered showers and thunderstorms
are expected across the area for Wednesday, mainly near the coast.

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 257 AM CDT Tue Oct 1 2024

Still waiting for deterministic models to resolve discrepancies in
fluctuating moisture content over Deep South Texas as well as try to
come to some temporal and placement consistency on surface features
over the Gulf of Mexico. One thing that remains constant is the
evolution of a mid-level low expected to form and settle over
Texas late this week. By the end of the forecast period (next Mon-
Tue) GFS/ECMWF have very different solutions of placement of this
mid-level low with GFS maintaining this feature over Texas while
the ECMWF weakens it considerably and even shows a weakening cold
front moving into South Texas as the mid-level low opens up in
response to a strong northern stream longwave trough. The other
uncertainty is the tropical wave over the Caribbean that the NHC
continues to monitor for tropical cyclone development. Latest IR
satellite loop shows broad low pressure centered over Jamaica with
water vapor channels showing circulations near the Yucatan
Peninsula and just east of Nicaragua. Currently, there is 10% and
40% chance of development in the next 2 to 7 days respectively.

With all this uncertainty the latest forecast package will not stray
far from the National Blend of Models (NBM) maintaining moderate to
high rain chances Thursday-Sunday. Rain coverage begins to wane
Monday and is shown to taper off Tuesday. Overall best coverage and
potential for pockets of heavy rainfall will be Friday and Saturday
where the NBM 90% percentile shows 1-3 inch rainfall amounts
along and east of I-69C. WPC QPF amounts indicate more reasonable
general amounts of 0.25 to 1 inch and up to 2 inches over SE
Cameron County including SPI Thursday-Sunday.

As for temperatures, NBM is persistent indicating near to
slightly above normal as is the GFS/ECMWF guidance. Of course, if
rain chances increase Friday and Saturday probability of
slightly below normal highs and lows enter the forecast.

&&

.AVIATION...
(18Z TAFS)
Issued at 1146 AM CDT Tue Oct 1 2024

Mainly VFR conditions are expected through the next 24 hours
across the RGV TAF sites. A brief 2-3 hour period of MVFR ceilings
will be possible after 15Z Wed across KBRO and KHRL as additional
boundary layer moisture enhances the chances at seeing thicker
cloud cover. A few brief showers will be possible toward the end
of this period as well due to this increased moisture.

&&

.MARINE...
Issued at 257 AM CDT Tue Oct 1 2024

Today through Wednesday..Generally favorable marine conditions will
prevail with light winds and low to moderate seas as high pressure
prevails across the Gulf of Mexico. Isolated to scattered showers
and thunderstorms will be possible across the coastal tonight and
Wednesday.

Wednesday night through Monday night...Broad surface low pressure is
expected to develop over the Bay of Campeche later this week with a
gradual increase in northeast winds and seas. A further increase in
winds and seas is possible this weekend as a tropical wave over the
Caribbean Sea tracks into the southern Gulf of Mexico and
potentially develop into a tropical cyclone. Currently, the National
Hurricane Center has a 10% and 40% chance of development in the next
2 to 7 days respectively. Although the current forecast shows some
delay in the increasing winds and seas, Small Craft Should Exercise
Caution or Small Craft Advisories headlines may be needed over the
weekend. Additionally, mariners can expect a substantial increase of
showers and thunderstorms as the weekend approaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             90  73  90  73 /   0   0  40  10
HARLINGEN               92  69  91  70 /   0   0  40   0
MCALLEN                 96  73  96  73 /   0   0  10   0
RIO GRANDE CITY         95  70  94  69 /   0   0  10   0
SOUTH PADRE ISLAND      87  79  86  79 /   0  10  40  20
BAYVIEW/PORT ISABEL     88  73  88  74 /   0   0  40  10

&&

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

$$

SHORT TERM...63-KC
LONG TERM....59-GB
AVIATION...80-MB