Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Brownsville Texas
249 PM CDT Friday Jul 25 2014
Short term /now through Saturday night/...similar to yesterday...
an isolated smattering of convection has developed this afternoon
along a westward-moving seabreeze. Additional convection may
develop between the ih-69c/US-281 and ih-69e/US-77 corridors this
afternoon...as mesoscale forcing from the seabreeze interacts with
ample boundary layer moisture and a weak upper-level shear axis.
And while I can't rule out a rogue shower or storm lingering into
the evening hours...the loss of daytime heating should result in
convection largely dissipating by sunset. For this reason...
forecast precipitation probabilities will be below 15 percent for
The influence of the upper-level shear axis on our weather will wane
tonight...allowing ridging to reassert itself across the forecast
area. A northeast to north flow aloft...circulating around the
ridge's center (in the Texas panhandle)...will dry out our boundary
layer for the remainder of the short term. Precipitable water
values will likely approach 1.5 inches across the region this
weekend. With little synoptic-scale forcing and a drier airmass
overall...it looks like dry weather will be on tap heading into the
Forecast temperatures will largely remain status quo for late July.
Lows will largely be in the middle and upper 70s...with highs
Saturday ranging from the lower 90s near the immediate coast to
about 100 west of ih-69c/US-281.
Thanks to weather forecast office Corpus Christi for collaborative efforts this
Long term /Sunday through Friday/...no changes were needed or
made to the long term portion of the forecast. Broad 500 mb high
pressure will generally remain centered over New Mexico and firmly
extended over the Rio Grande Valley and all of deep south Texas
through the period. Precipitable waters values will linger near
1.5 inches through much of the period...but could fall to near 1
inch towards the end. No precipitation was inherited from the
previous shift...and this trend was maintained for this forecast
cycle due to the dry atmosphere combining with the 500 mb high
pressure system. Slightly above normal temperatures were also
inherited...and kept...although some argument could be made to
increase them about 1 to 3 degrees...especially daytime highs...
due to expected limited cloud cover and a drying atmosphere.
Marine...tonight through Saturday night...pressure gradient should
strengthen a bit over the marine area heading into the first half
of the weekend...allowing increased wind speeds between 15 and 20
knots to be seen by Saturday. Even with the increased wind
speeds...wave and wind criteria should remain below exercise
caution thresholds into the weekend. While there may be a few
showers over the Gulf waters early Saturday morning...the coverage
is expected to be even more isolated than this morning. As
such...precipitation probabilities over the marine area will
remain below 15 percent during the short term. /Butts/
Sunday through Friday...small craft may need to exercise caution
on the Laguna Madre Sunday and Monday as a result of surface high
pressure centered over the eastern Gulf of Mexico interacting with
thermal low pressure over northern Mexico. Otherwise...generally
light to moderate winds and low to moderate seas are expected for
the Lower Texas coast with high pressure the main influence over
the Gulf of Mexico. Small craft advisories are not likely to be
needed for the Lower Texas coastal waters.
Preliminary point temps/pops...
Bayview/Port Isabel 80 95 80 94 / 10 10 10 0
Brownsville 78 97 79 94 / 10 10 10 0
Harlingen 76 100 79 97 / 10 10 10 0
McAllen 78 100 79 99 / 10 10 10 0
Rio Grande City 79 102 78 99 / 10 10 10 0
South Padre Island 80 91 81 90 / 20 20 10 0
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