FXUS64 KBRO 221940

Area Forecast Discussion
National Weather Service Brownsville TX
240 PM CDT Sat Sep 22 2018

.SHORT TERM (Now through Sunday Night): A weak front moving south
into the CWA during the first period will set up light to
moderate isolated to scattered showers with a few embedded
thunderstorms. Forecast precipitable water values of over two
inches are higher than average, even for this time of year, but
otherwise not seeing a lot of support for more organized or
stronger convection tonight. The models show the front pushing to
the coast tonight and stalling and, after a few lingering morning
showers across the eastern half of the area, drier air will move
in from the west and will temporarily take over most of the area
Sunday afternoon, with rain chances ending, except possibly near
the immediate coast. By Sunday night, east to southeast winds will
begin to carry the front and isolated to scattered showers back
west over the coast. A weak surface moisture boundary may then
form the demarcation between moist air over the southeast portion
of the CWA and a drier air mass and a few less clouds over the
northwest half of the CWA. Overnight low temperatures will be
mainly in the 70s while high temps Sunday will be mainly in the

.LONG TERM (Monday through Saturday): A broad 500mb inverted
trough across the central Gulf of Mexico and a weak 500mb
shortwave trough across south Texas Monday will continue to
provide a slight chance of showers and thunderstorms across the
CWA...mainly across the coastal sections. Low to mid level
moisture remains high across the northwest Gulf coast even as
drier air aloft continues to move across southwest Texas Tuesday.
The global models are in better agreement with the 500mb ridge
across the western North Atlantic building westward into the
Northwest Gulf of Mexico Wednesday. Rain chances are progged to
increase Wednesday and a chance of showers and thunderstorms is
expected to continue across deep south Texas through the rest of
the week into the weekend as a shear axis across northern Mexico
brings moisture across northeast Mexico northward into the Rio
Grande valley. In addition...a 500mb low/inverted trough across
northwest Mexico Friday draws moisture northward around the
western periphery of the 500mb ridge across the northeast Gulf of

.MARINE (Now through Sunday night): The approach of a weak front
may briefly disrupt the prevailing southeast winds in the short
term. Winds will remain light to moderate, but how far the front
pushes offshore will determine the wind direction. The forecast
calls for a period of northwest winds on Sunday for the nearshore
and Bay waters. The front may push back west Sunday night into
Monday, allowing east to southeast winds to regain the upper hand.
Showers and thunderstorms will remain in play for the marine
areas in the short term with the surface boundary providing a
focus for instability.

Monday through Thursday...Light south to southwest winds will
prevail across the coastal waters Monday with surface low pressure
across northeast Texas. The pressure gradient will remain weak
across the lower Texas coast Tuesday through Thursday. Light south
to southeast winds should prevail across the coastal waters
Tuesday through Thursday as a weak cold front moves into central
Texas Wed night and stalls.

BAYVIEW/PORT ISABEL 78 87 76 91 / 70 40 20 20
BROWNSVILLE 79 89 76 93 / 60 50 20 20
HARLINGEN 77 89 75 94 / 60 30 20 20
MCALLEN 76 90 76 96 / 50 20 10 20
RIO GRANDE CITY 75 88 74 96 / 30 10 10 20
SOUTH PADRE ISLAND 79 86 78 88 / 60 50 30 30



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