819
FXUS64 KBRO 291720
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
1220 PM CDT Mon Apr 29 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday)
Issued at 324 AM CDT Mon Apr 29 2024

The start of the short term forecast is expected to be a bit similar
to the last several days, with warm and humid conditions. The
difference for today however, is that the onshore flow is not
expected to be as strong. With a zonal flow aloft set up for the
majority of the short term forecast period and a weak mid-level
ridge starting to inch in at the end of the period. The upper
level synoptic flow is not the best for any sort of development
for showers and thunderstorms. While SPC still does have Deep
South Texas and the Rio Grande Valley in a general thunderstorm
outlook with a sliver of Zapata County in a Marginal Risk (level 1
of 5) for today. Tomorrow they have the entire region in just a
general thunderstorm outlook. While the onshore flow will help
bring in some low-level moisture, and while there is also plenty
of MUCAPE with values over 3000 J/kg. The biggest hindrance to the
growth of showers and thunderstorms is the dry air in the middle
to upper levels of the atmosphere. Another factor is that the
forecast soundings for the region still show a cap persisting into
the afternoon as well. While the conditions are not favorable,
not going to rule out a stray shower or thunderstorm popping for a
short period of time. Thus, rain chances for the short term
period are in the range of 20 to 30 percent.

As for temperatures, thanks to the onshore flow, the warm
temperatures are expected to persist through the period. The high
temperatures for today and tomorrow look to be in the 90s for most
of Deep South Texas and the Rio Grande Valley. While along the coast
and on the island the high temperatures will be in the upper 80s.
While some low-level clouds might be present during the morning
hours, they are expected to mix out before the day time heating
really gets going during the afternoon. As for the low temperatures,
all of Deep South Texas and the Rio Grande Valley will be in the
70s.

Finally, the High Risk of Rip Currents has been extended once again,
as the swell period of 8 seconds and wave heights around 5 feet look
to persist for the next 36 hours. Swell period looks to be remain
elevated as long as the high pressure over the Gulf of Mexico for
the next couple of days until the said high pressure weakens
allowing for the winds and seas to come down over the Gulf of Mexico.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 324 AM CDT Mon Apr 29 2024

Synoptic pattern has not varied much over the last few model runs
with a quasi-zonal flow over much of the CONUS this week. The
northern side a subtropical ridge edges into South Texas while
farther north an elongated trough will pass west to east over the
Northern Rockies to the Great Lakes.

The subtropical ridge to provide above normal temperatures for much
of the week with model guidance still indicating amonalies of 3 to 8
degrees for highs and lows which translates to highs in the 90s and
lows in the 70s. Dew points remain high elevating after heat indices
100-107 each afternoon. The most dangerous heat days look to be
Thursday and Friday where the probability of heat indices greater
than 105 degrees are low to medium or 20-50%.

A steady state moderate pressure gradient between ridging over the
Gulf and low pressure across the Southern Plains maintains daily
breezy to occasional windy conditions. On average the region can
expect to see daytime breezes in the 15-25 mph range with Wednesday
and Thursday looking like the windiest days

Rain chances continue to be limited through the work week with
isolated convection still in the offering Wednesday and Thursday
with some added moisture depth working with a weak disturbances in
the westerly flow. Better chance continue to be indicated Friday and
Saturday as sufficient moisture pools in advance of a frontal
boundary moving into Central or even Southcentral Texas. PoPs remain
low across the board, 20-40 percent with best chances west of I-69C.

&&

.AVIATION...
(18Z TAFS)
Issued at 1220 PM CDT Mon Apr 29 2024

Satellite imagery depicts SCT to BKN cloud cover across the
region. Ceilings have improved to VFR across the region and should
remain VFR through the afternoon hours, with only brief periods of
SCT to BKN MVFR ceilings. Persistent low level southerly to
southeasterly flow will allow for MVFR ceilings to overspread once
again this evening, with high res guidance indicating MVFR
ceilings beginning between 00-03Z for the TAF sites. Low end MVFR
ceilings will prevail through at least 15-16Z Tuesday, with a low
potential for IFR ceilings. Otherwise, southeast winds will shift
to the east this afternoon, and once again to the southeast
overnight with speeds generally below 10 knots.

&&

.MARINE...
Issued at 324 AM CDT Mon Apr 29 2024

Today through Tuesday..Conditions over the waters are expected to
continue to improve during the day as the winds start to weaken.
Light to moderate onshore flow with moderate seas is the expected
trend through Tuesday. Isolated showers and thunderstorms are
possible through Tuesday and may cause locally elevated winds and
seas.

Tuesday through Sunday: A static weather pattern will maintain a
moderate pressure gradient for the remainder of the week and into
next weekend. Weaker surface ridge extending over the Eastern Gulf
to combine with lower pressure over NE Mexico and West Texas
provide moderate onshore winds and a steady state sea state of 4
to 6 feet. This should be maintain periodic small craft caution
wording for most of the week.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             91  77  89  77 /  20  10  20   0
HARLINGEN               92  74  92  74 /  10  10  20   0
MCALLEN                 94  76  93  77 /  10  10  20   0
RIO GRANDE CITY         95  74  93  75 /  20  10  20   0
SOUTH PADRE ISLAND      81  76  81  76 /  10  10  20   0
BAYVIEW/PORT ISABEL     87  74  87  74 /  20  10  20   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Tuesday evening for TXZ451-454-455.

GM...None.
&&

$$

SHORT TERM...64
LONG TERM....59
AVIATION...22-Garcia