Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus64 kbro 211037 aaa 
afdbro

Area forecast discussion...updated
National Weather Service Brownsville Texas
537 am CDT Sat Sep 21 2019

Discussion...updated for latest aviation discussion below.
&&

Aviation...VFR will continue to be the rule through the next 24
hours in the forthcoming tafs. Breezy winds are anticipated for
the daylight hours of today before diminishing around sunset.
Isolated convection will occur, but will not be widespread enough
to warrant inclusion in the tafs for the aerodromes.
&&

Previous discussion... /issued 355 am CDT Sat Sep 21 2019/

Short term (today through sunday): the most recent kbro upper
air sounding revealed a precipitable water content of 1.78 inches
in the atmospheric column. This relatively deep moisture will
persist through the forecast period, and when combined with the
approach from the east of a weak inverted 500 mb trough, isolated
showers will result across the bro County warning forecast area. Above normal temperatures
are also anticipated due to the limited rain chances and
corresponding lesser cloud cover.

Long term (sunday night through friday): the 500 mb mid-level
ridge stretched across the Gulf Coast states to start the period
will gradually break down and slide towards the southeast through
early to middle of next week. An inverted trough in the southern
Gulf of Mexico will be expected to move around the periphery of
the weakening ridge. This inverted trough is expected to move
into/across our region early in the week. The latest runs keep
this weak disturbance or at least mid-level weakness across the
region through midweek while a cutoff low is positioned across
the southwest U.S. Late in the period, mid-level ridging will
nudge back westward into our region as the cutoff low opens up
into a shortwave and propagates into the Central Plains. The
models, however, do show a possible second inverted trough
approaching the region by next weekend.

The latest model blends and MOS guidance continue to highlight
that Monday features the best chance for convection across the
region with pops as high as 30/40 percent. Slight chances for
showers and thunderstorms will otherwise trend through Friday,
with best chances along and east of Highway 281 with the sea
breeze. The European model (ecmwf) is notably drier after Monday compared to the
GFS. As a result, the European model (ecmwf) guidance is also trending a bit
warmer compared to the GFS output as well. I have elected to
trend closer to the warmer side of the guidance throughout the
long term period with afternoon high temperatures still above
average levels with higher heat indices. However, I did drop
the overnight lows by a degree or two for quite a few locales,
especially for portions of the northern ranchlands.

Marine (now through sunday): buoy 42020 reported east-southeast
winds around 16 knots gusting to around 19 knots with seas
slightly under 4.5 feet with a period of 6 seconds at 250 CDT/750
UTC. An enhanced pressure gradient over the western Gulf of Mexico
will continue to produce breezy winds and moderate seas along the
Lower Texas coast. Small craft exercise caution will likely be
needed for portions or all of the Lower Texas coastal waters
during the period.

Sunday night through friday: light to moderate south to southeast
winds and generally low to moderate seas of between 3 to 5 feet
will be expected throughout the long term period as a result of a
rather modest pressure gradient at the surface. Winds and/or seas
could reach small craft exercise caution levels at times. Small
Craft Advisory conditions are not expected. Isolated to scattered
marine showers and thunderstorms will remain possible through the
period. Any heavier cells may result in locally gusty winds and
locally enhanced sea state.
&&

Bro watches/warnings/advisories...none.
&&

National Weather Service Glossary of Abbreviations