983
FXUS64 KBRO 170548 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1248 AM CDT Fri May 17 2024

...New AVIATION...

.SHORT TERM...
(Tonight through Friday night)
Issued at 243 PM CDT Thu May 16 2024

Tonight, we will continue to see a dryline pushing into the Rio
Grande Plains, possibly making it to the mid-valley. A cold front
will also continue to slowly sag southeast, but remain northwest
of the CWA through tomorrow night. These two features along with a
mid/upper level trough moving over the region and outflow left
over from tonight`s thunderstorms well north of the BRO CWA will
give us a chance of seeing thunderstorms Friday. Chances have been
bumped up a bit from previous forecasts to 30 to 40%. Some of
this activity could be strong to severe across the northern
Ranchlands with forecast soundings showing CAPE values well above
3000 J/kg, lapse rates between 7C and 8C, and favorable shear.
The main threats from this activity will be large hail and winds
in excess of 60 mph. The Storm Prediction Center has put northern
portions of Jim Hogg, Brooks and Kenedy counties in a Slight Risk
for severe weather (Level 2 out of 5), the remainder of Kenedy,
Brooks and Jim Hogg and Zapata counties in a Marginal risk of
severe weather (level 1 out of 5). The best timing for severe
weather at this time looks to be Friday morning into Friday
afternoon. The remainder of Deep South Texas remains in a general
thunderstorms risk through the day Friday. All activity should
dissipate/move out of the area Friday evening.

Temperatures will be warm again tomorrow, with highs in the mid to
upper 90s. Combined with high humidity, "feels like" temperatures
are forecasted to be a bit higher than today, so a Heat Advisory
may be needed tomorrow afternoon. One caveat to this will be if
showers and thunderstorms move through the area, especially in the
Valley, or cloud cover remains, temperatures will not be quite as
high, and thus not warrant a Heat Advisory. Overnight lows will
remain warm and muggy, with lows in the 70s, with areas along the
cost and a few spots in the Valley hanging in the low 80s.

Otherwise, hazy conditions will persist through this evening, thanks
southerly winds and burning in Mexico and Central America. Haze
should clear out tomorrow.

&&

.LONG TERM...
(Saturday through next Thursday)
Issued at 243 PM CDT Thu May 16 2024

The main story for the long term will be warm temperatures through
next week. On Saturday, an upper level disturbance will move
northeast with high pressure quickly building in its wake. This will
lead to warming temperatures with triple digits returning to the Rio
Grande Plains Saturday afternoon with upper 90s across much of the
remainder of the CWA. The cool spot will be right along the coast
where temps range from the mid 80s to low 90s. The triple digits
will expand eastward through the week, reaching the coastal counties
by Tuesday. High humidity accompanying these hot temperatures will
lead to "feels like" temperatures exceeding 110 degrees in many
areas and Heat Advisories may be needed. Overnight temperatures will
remain warm and muggy with lows only falling into the upper 70s to
low 80s.

The NWS HeatRisk tool highlights a major risk of heat-related
impacts for those that are not properly hydrated or do not have
effective cooling in place through the week. No relief from the heat
is expected in the way of rainfall through the period with
subsidence in place.

&&

.AVIATION...
(06Z TAFS)
Issued at 1246 AM CDT Fri May 17 2024

Through 06z Sunday....MVFR conditions were taking place at the TAF
sites under a SCT-BKN deck of stratus clouds with ceilings between
1,000-1,500 feet AGL and haze which is restricting visibilities down
to 4-6 statute miles. Much of the TAF period including the next 6-9
hours will continue to experience MVFR cigs and/or visibilities. There
could be times especially during the day today where VFR conditions
are seen.

There is a non-zero, low grade probability of showers and
thunderstorms to develop this morning and then again this
afternoon/evening as a frontal boundary approaches. Opted to keep
headlines out of the TAFs given the continued uncertainty with the
likelihood and coverage of storms. If confidence for storm
chances increase in the hours ahead, will make amendments in the
form of a TEMPO or Prob30 to the TAFs to reflect the increase
confidence.

Winds are currently out of the southeast at 5-10 kts. An outflow
boundary from earlier convection to our north could shift winds out
of the east-northeast towards daybreak. Otherwise, expect for light
and variable winds during the morning hours. During the afternoon
hours today, expect for winds to become east-northeasterly between 5-
10 kts.

&&

.MARINE...
Issued at 243 PM CDT Thu May 16 2024

Now through Friday night: Slightly adverse conditions will
continue on the Laguna Madre and Gulf waters through tonight with
elevated winds. On Friday, more favorable conditions return.
Friday into Friday night we could see some thunderstorms move over
the waters off the lower Texas coast which could lead to
localized high winds and seas.

Saturday through Wednesday: Light to moderate winds with seas of
generally 3 to 5 ft will persist through the week. A slighlty
enhanced pressure gradient each afternoon, especially next week,
could lead to periods of Small Craft Caution.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             96  78  96  78 /  20  10  10   0
HARLINGEN               95  75  97  75 /  30  10  10   0
MCALLEN                 96  78 100  78 /  30  10  10   0
RIO GRANDE CITY         95  76 100  76 /  40  20   0   0
SOUTH PADRE ISLAND      86  79  87  80 /  20  20  10   0
BAYVIEW/PORT ISABEL     92  77  92  77 /  30  10  10   0

&&

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

$$

SHORT TERM...68-McGinnis
LONG TERM....68-McGinnis
AVIATION...23-Evbuoma