847
FXUS64 KBRO 130918
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
418 AM CDT Mon May 13 2024

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(Today through Tuesday)
Issued at 338 AM CDT Mon May 13 2024

The main concerns in the short term will be the heat and the low
probability for strong to severe thunderstorms today.

Southerly winds and elevated 850mb tempeatures of 24 to 25(C) to
allow for surface temperatures to climb 5 to 10 degrees above
normal. Highs today are expected to range from the 80s near the
coast to the triple digits across the Rio Grande Plains. The daily
records at Brownsville 96 in 2011 and Harlingen 98 in 2011 may be
reached.

In addition, the much warmer temperatures and high humidity will
allow heat index values to up 114 degrees, especially along and east
of the I-69C/US 281 corridor, for a few hours this afternoon. Hence,
a Heat Advisory is in effect from 1 pm the afternoon until 7 pm this
evening for Inland Cameron, Hidalgo, Inland Willacy and Inland Kenedy
Counties. A dryline is expected to push into the far western
counties this afternoon which may keep the heat indices slightly
lower, 105 to 110, with highs to reach into the lower 100`s. Warm
and humid conditions are expected again tonight with lows in the
70s to around 80 at the beaches. High temperatures on Tuesday will
range from the lower 80s at the beaches, low to mid 90s across
the Rio Grande Valley and the upper 90s to around 100 degrees
across the Rio Grande Plains. Will lean towards a blend of the NBM
and previous forecast for temperatures and dewpoints for today
through Tuesday, as the NBM appears a little too warm.

Low rain chances (20 to 30 percent) are forecast for this morning
into the afternoon with an elongated mid-level disturbance passing
overhead. Brownsville radar currently indicates some activity moving
across the Upper Valley and the northern ranchlands. The atmosphere
remains conditionally unstable with a strong low level cap (stronger
eastern counties) and elevated MUCape of 3000+ J/kg. There is a low
probability (20 percent) for strong to severe thunderstorms today
which is highly dependent on the track of the mid-level disturbance
and if the cap weakens. The Storm Prediction Center /SPC/ has all of
Deep South Texas in a marginal risk for the entire area for today
and tonight.

Finally, continued slightly elevated seas will result in a Moderate
Risk of rip currents at the local beaches through Tuesday.

&&

.LONG TERM...
(Tuesday Night through Sunday)
Issued at 338 AM CDT Mon May 13 2024

A weak cold front is forecast to intrude into the BRO CWFA on
Friday. When combined with a series of disturbances riding within
a west-southwest to east-northeast 500 mb flow, isolated showers
and thunderstorms will result, mainly in the Wednesday through
Friday time frame. Above normal daytime highs and overnight lows
are also anticipated, and highs on Thursday through Sunday,
combined with relative humidity percentages, may require a Heat
Advisory for portions of Deep South Texas and the Rio Grande
Valley on those days.

&&

.AVIATION...
(06Z TAFS)
Issued at 1227 AM CDT Mon May 13 2024

Low MVFR stratus and light southeast winds prevail across Deep
South Texas early this morning. BRO radar indicates some isolated
convection northeast of HRL. These showers and thunderstorms will
continue to move to the northeast and are not expected to impact
the RGV aerodromes. Otherwise, MVFR ceilings should remain in
place through the overnight hours. There could be brief instances
of IFR ceilings as well late tonight. Ceilings are expected to
improve to VFR levels mid to late morning. MVFR ceilings may
return late in the period at BRO, around 04Z.

&&

.MARINE...
(Today through Tuesday)
Issued at 338 AM CDT Mon May 13 2024

Weak to moderate southerly flow and moderate seas of 2 to 4 feet
will prevail along the Lower Texas Coast through Tuesday. Isolated
to scattered showers and thunderstorms will be possible today
which could lead to locally higher winds and seas.

(Tuesday Night through Sunday)
A couple of weak cold fronts are still expected to intrude into
the western Gulf of Mexico waters during the period, but high
pressure will still generally prevail. Light to moderate winds
and generally moderate seas will occur along the Lower Texas
Coast.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             95  78  92  78 /  20  10  10   0
HARLINGEN               98  75  93  74 /  20  10  10   0
MCALLEN                100  78  97  77 /  10  10  10   0
RIO GRANDE CITY        102  76  97  75 /  10  10  10  10
SOUTH PADRE ISLAND      85  79  85  79 /  20  10  10   0
BAYVIEW/PORT ISABEL     93  77  89  76 /  20  10  10   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 1 PM this afternoon to 7 PM CDT this evening
     for TXZ251-253>255-353.

GM...None.
&&

$$

SHORT TERM...Caceres-63
LONG TERM/UPPER AIR...Tomaselli-66