Area forecast discussion...updated
National Weather Service Brownsville Texas
1231 PM CDT Sat may 25 2013
Discussion...updated for latest aviation discussion below.
&&
Aviation...cumulus field continues to bubble this afternoon with Gulf
moisture still in place. Morning thunderstorm activity has moved
off to the north...with a few residual showers trying to form to
the south. With shower activity remaining few and far
between...kept thunderstorms in the vicinity out of tafs for now.Small possibilities of
rain at all three sites continue through the evening. Cloud deck
thins briefly before sunset...but returns before midnight. Better
clearing as ridging aloft returns in the wake to todays shortwave.
&&
Previous discussion... /issued 322 am CDT Sat may 25 2013/
Short term.../today through Sunday/...well so much for a dry forecast
in the short term. In the wake of the mesoscale convective complex
that rolled out of Mexico and across most of the Rio Grande Valley
and deep south Texas on Friday...isolated showers are developing
over mainly the central and eastern portions of the bro County warning forecast area right
now...possibly due to old outflow boundaries locally...but more
broadly due to 500 mb low pressure spinning over the Lone Star state
at this time. Models 24 hours ago had this feature as a simple open
trough that was prognosticated to eject northeast out of the region...with
middle-level high pressure continuing its reign in its wake. Now...the
GFS...NAM...and European models all generally indicate a closed low
over Texas...with varying degrees of precipitation potential for the
Rio Grande Valley and deep south Texas. GFS appears to be the driest
and indicates little precipitation...while the European suggests
isolated convection...and the NAM GOES more scattered. Decided to go
more European for today...a decision that will leave US in decent
agreement with neighboring weather forecast office crp...and is a slight trend upward
from what was inherited from the previous shifts here. Would not at
all be surprised if incoming shifts raise the precipitation chance a
few notches upwards...especially if daytime heating destabilizes an
already moist atmosphere. Opted to go with no rainfall for tonight
and Sunday...as the 500 mb low appears to lift northeast...leaving
the Rio Grande Valley and deep south Texas on the more stable back
side of that feature. Given the expected clouds and rainfall through
the period...temperatures should make it to around normal for this
time of the year...but still very warm.
Long term...Sunday night through Saturday night/...
at the beginning of the long term forecast...as the ridge builds
across the west central part of the state another trough enters the
northwest Pacific coast. The southeast flow will continue through
most of the week as a broad surface high pressure strengthens across
the eastern plains and the Lee trough deepens. As the trough digs
southward along the Pacific coast the gradient will continue to
strengthen increasing winds across the Rio Grande Valley. This southeast
flow will continue to advect Gulf moisture making the area more
favorable for showers to develop beginning Tuesday afternoon into
Wednesday. This shower activity will continue especially in the
afternoon hours as the abundant moisture and surface heating will
provide a more favorable environment for convection. High
temperatures will continue to warm into the middle to upper 90s
through the week with southeast winds increasing Tuesday through Friday
with the approach of this trough. The southeast winds will begin to lower
by Friday but the chance of showers will continue. Low
temperatures will remain in the middle to upper 70s for most of the
week.
Marine...today through Sunday...buoy 42020 reported southeast winds
around 18 knots gusting to around 21 knots with seas slightly under
5 feet with a period of 6 seconds at 02 CDT/07 UTC. Moderate winds
and seas are expected along the Lower Texas coast through the period
as high pressure over the western Gulf of Mexico interacts with low
pressure over the Texas Panhandle. Small craft will likely need to
exercise caution for portions of the Lower Texas coastal waters for
today through Sunday.
Sunday night through Saturday...
an upper level trough over the Pacific coast will dig southward by
Tuesday into Wednesday increasing the southeast winds. The seas will begin
to build up to 6 feet with conditions close to Small Craft Advisory
conditions over the Gulf waters. This conditions will continue through
the end of the week as the winds lower. Chance of showers will be
possible through the week as conditions are favorable for afternoon
isolated showers. Seas will begin to improve by late Friday.
&&
Bro watches/warnings/advisories...
Texas...none.
GM...none.
&&
$$
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