018 
FXUS64 KBRO 242344 AAA
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
644 PM CDT Mon May 24 2021

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...Showers/thunderstorms will pretty much have 
dissipated or moved north of the region by or shortly after 
sunset. VFR conditions for the evening with MVFR ceiling forming 
after midnight or closer to sunrise Tuesday. Confidence is low on
how widespread Ceiling will become and may be more patchy and
short-lived. A few coastal showers to form overnight possible
approaching the coast around sunrise. Confidence and probability
is low on if showers may impact the regional airports with the
main upper disturbance will be well removed from Deep South Texas
Tuesday. Light southeast winds prevail tonight becoming moderate 
tomorrow afternoon.

&&

.PREV DISCUSSION... /issued 323 PM CDT Mon May 24 2021/ 

SHORT TERM (Tonight through Tuesday Night): Sea breeze 
enhanced convection is underway this afternoon, with 
thunderstorms moving northwest and north along the line with some 
training and moderate downpours. The convection will continue, 
mainly for eastern sections, for a few more hours before 
conditions settle down this evening. Factors are a weakness aloft 
and ample low level moisture. Gusty winds and occasional to 
frequent cloud to ground lightning are accompanying the main 
cells.

Ridging will continue over the Southeast United States with 
synoptic scale high pressure over the Gulf supporting moderate 
southeast breezes. Conditions will be slightly less favorable for 
areawide convective coverage on Tuesday as the mid level weakness 
fills, but the NAM, for example, suggests another sea breeze event
on Tuesday. Temperatures will be near normal east but slightly 
above normal west on Tuesday.

Tides are running over a foot above predicted, leading to beach 
run-up and overwash, especially around high tide. High tide at 
Brazos Santiago is forecast for 4:45 AM on Tuesday, leading to 
possible minor coastal flooding. Heading toward a full moon plus 
persistent east swell may lead to an elevated (potentially high) 
risk of rip currents on Tuesday as well.

LONG TERM (Wednesday through Monday): 500 mb ridging will be
building over the RGV/Deep South TX on Wed with the ridging
persisting through Fri and into Sat. The deep layer tropical
moisture feed over the region will be shut down later this week
which will allow for above normal temps and below normal pops to
prevail. Then a rather large and elongated 500 mb trough axis 
will start digging into the Western States. This western trough
axis will start pushing eastwards towards the South Central Plains
States over the upcoming weekend. But the 500 mb ridging will
still likely remain entrenched over the region through next Mon.
Some better moisture values may start to edge into W/N TX over the
weekend, but do not expect much in the way of serious moisture
advection to occur over the RGV. So for now will hold off on
bringing in any serious pops throughout the longer range period. 

The ECMWF and GFS models are in decent agreement in the overall
500 mb pattern through Days 7/8. However the ECMWF is more bullish
in the moisture advection ahead of the West Coast 500 mb trough
and accordingly is a little bit wetter for pops for the weekend.
The longer range temps from both models are in reasonable
agreement with the ECMWF coming in slightly warmer versus the GFS. 

The overall confidence level for the longer range forecast wording
is above average this afternoon. 

The latest longer range tropical model guidance and 5 day outlook
from NHC indicates that the Atlantic Basin will remain quiet for 
the rest of this work week. 

MARINE (Today through Tuesday Night): Moderate southeast winds 
through the forecast. Moderate to sometimes slightly higher seas 
on the Gulf waters, especially offshore, due to persistent east 
swell. A slight uptick in winds/waves may occur on the offshore 
Gulf waters tonight, with borderline small craft advisory 
conditions.

Wednesday through Saturday Night: The PGF will likely slacken
slowly from Wed onwards as broad surface ridging persists over the
Gulf of Mex. This will allow moderate winds and seas to persist
with no SCA conditions expected through Sat Night. 

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  75  86  76  86 /  10  10   0   0 
BROWNSVILLE          77  88  77  90 /  10  10   0   0 
HARLINGEN            75  89  76  90 /  10  10   0   0 
MCALLEN              75  92  76  93 /  10  10   0   0 
RIO GRANDE CITY      74  96  76  97 /  10  10   0   0 
SOUTH PADRE ISLAND   77  81  78  81 /  10  10   0   0 

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 7 PM CDT this evening for TXZ256-257-
     351.

GM...None.
&&

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

59-GB/99