928
FXUS64 KBRO 150513 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1213 AM CDT Sun Sep 15 2024

...New AVIATION...

.SHORT TERM...
(Tonight through Sunday night)
Issued at 218 PM CDT Sat Sep 14 2024

Upper level ridging is expected to hold through the short term,
which, combined with moist onshore southeasterly flow, has resulted
in an increase in temperatures, relative humidity and heat indices,
or the `real feel` temperature. This has resulted in a Heat Advisory
today for Brooks and Hidalgo counties as well as Inland Cameron,
Inland Willacy and Inland Kenedy counties, effective till 5 PM this
afternoon as temperatures are forecast to exceed 111 F for at least
2 hours and potentially reaching as high as 114 F degrees.

Overnight, remnant moisture from Tropical Storm Ileana, located over
the southern Gulf of California and off the western Mexico
coastline, will be carried by mid-to-upper level winds over Deep
South Texas, bringing scattered to overcast skies. Convection over
the Sierra Madre Mountains may spill over the western portions of
the County Warning Area (CWA) this evening and into the overnight
hours, bringing a 15 to 30% chance of showers and thunderstorms to
the upper RGV as well as Jim Hogg and Zapata counties. By the
predawn hours and into Sunday morning, vorticity associated with a
mid-level shortwave trough, is anticipated to increase over the CWA
in a west-to-east fashion, providing a mid-level lifting mechanism
for low-level moisture to generate a 40% chance of showers and
thunderstorms across Deep South Texas tomorrow morning. By the
afternoon, continued vorticity advection is expected to result in
numerous showers and thunderstorms, some of which may contain brief
and heavy downpours, especially across the Rio Grande Plains and all
of the RGV, where POPs could range between 50% to 70% into the early
evening hours. WPC QPF totals indicate the potential for 0.25 to
0.75 of an inch of rain across the mid-upper RGV and Rio Grande
Plains. However, a few inches of rain is possible within heavier and
longer-lasting downpours. WPC has not included any of the CWA within
an Excessive Rainfall Outlook, but heavy rain may lead to nuisance
flooding in some locations. Overnight, POP`s decrease across most
of Deep South Texas, but an isolated chance of showers and
thunderstorms remains across the RGV closer to the border.

Overnight lows tonight will range from the upper 70s with lower 80s
across the RGV and the barrier islands. Temperatures tomorrow will
reach into the upper 80s for barrier islands and lower to mid 90s
for inland Deep South Texas. Tomorrow night`s lows will keep mostly
in the upper 70s with lower 80s along the Gulf coastline.

&&

.LONG TERM...
(Monday through next Saturday)
Issued at 218 PM CDT Sat Sep 14 2024

Rain chances trend downward but do not go away completely through
the long-term. 250-500mb ridge builds and becomes anchored over
Texas as large scale mid-upper level troughs set up over the
western and eastern portions of the country. A few perturbations
in the southwest flow aloft and remnant moisture from Pacific
Tropical Storm Ileana should be sufficient to squeeze out a few
showers or thunderstorms Monday. Beyond Monday, surface southeast
flow maintains seasonal moisture levels providing a slight chance
of daily sea breeze showers or isolated thunderstorms. Probability
coverage will only be in the 10-20 percent range at best and with
the ridge building and more subsidence than lift the sea breeze
will have a tough time organizing which will limit convection
beyond the coastal counties Wednesday-Friday.

Seasonal to slightly above normal temperatures continue to supported
by model output with heat indices on the high end but just below
heat advisory criteria at this time.  Maximums to reach upper 80s at
the beach, 90s inland to near 100 for the Rio Grande Plains with 70s
to near 80 at the coast should suffice for low temperatures.

&&

.AVIATION...
(06Z TAFS)
Issued at 1204 AM CDT Sun Sep 15 2024

Mostly VFR conditions are expected for the TAF period at all TAF
sites. Light to moderate southeasterly winds are expected through
the period as skies during the period range from mostly sunny to
partly cloudy. Short periods of MVFR skies are possible, with
isolated rain chances possible during the afternoon hours, but
should diminish by the evening.

&&

.MARINE...
Issued at 218 PM CDT Sat Sep 14 2024

Tonight through tomorrow night...Ideal marine conditions are
anticipated with light to gentle southeasterly winds and low seas.
Isolated showers and thunderstorms are possible Sunday morning
becoming scattered in the afternoon, lasting into the evening hours
followed by a slight chance of showers and thunderstorms. Lightning
and enhanced winds and seas are possible within thunderstorms.

Monday-Friday...Gentle to light onshore breezes coupled with low
seas are expected to persist along the lower Texas coastal waters
Monday and Tuesday. Surface pressure gradient remains relaxed with
mid-level high pressure build over Texas and surface ridge remaining
weak across the Gulf of Mexico.  As heat builds inland through the
week a moderate onshore flow develops Wednesday-Friday each
afternoon impacting mainly the Laguna Madre. Probability for
Exercise Caution statement remains below 20 percent Monday and
Tuesday, with increasing chances over 50 percent mid to late in
the week. Small Craft Advisories probability remains below 10
percent.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             90  78  90  77 /  60  40  50  10
HARLINGEN               91  75  91  75 /  60  20  50  10
MCALLEN                 94  79  95  78 /  70  30  50  10
RIO GRANDE CITY         91  76  92  76 /  70  40  50  10
SOUTH PADRE ISLAND      87  81  87  81 /  50  40  40  20
BAYVIEW/PORT ISABEL     89  77  89  77 /  50  30  40  10

&&

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

$$

SHORT TERM...65-Irish
LONG TERM....59-GB
AVIATION...64-Katz