Area Forecast Discussion
Issued by NWS Brownsville, TX
FXUS64 KBRO 230508 AAB
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1208 AM CDT Sun Apr 23 2017
.DISCUSSION...Updated for latest aviation discussion below.
.AVIATION...Satellite and radar images as well as surface
observations indicate isolated convection across southeast
portions of the CWA late tonight. Mostly mid to high level clouds
were across most of the area. Ceilings were near 2000ft at KEBG to
near 6500ft at KHRL. Expect MVFR conditions to continue to develop
late tonight as a cold front moves through the Rio Grande valley.
Elevated convection is also expected to develop in the wake of the
front the rest of tonight into early Sun morning before drier and
cooler air moves in from the north. VFR conditions will prevail
after 15Z Sunday as high pressure continues to build into deep
south Texas in the wake of the cold front.
.PREV DISCUSSION... /issued 645 PM CDT Sat Apr 22 2017/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...A cold front currently extending from near Falfurrias
to Rio Grande City will continue to move south across Deep South
Texas through the evening. FROPA expected between 02Z to 05Z for
the TAF locations. Gusty north winds with ceilings lowering to
MVFR will develop in the wake of the front. Rain chances expected
to increase slightly tonight, especially between 06Z to 12Z, as
the 850mb front passes overhead. VFR conditions will prevail after
15z Sunday as high pressure builds into the region.
PREV DISCUSSION... /issued 256 PM CDT Sat Apr 22 2017/
SHORT TERM (Tonight through Sunday Night): The highly anticipated
cold front is currently draped across South Texas or from an area
just to the northwest of Laredo and angled northeast toward
Refugio. Front will move in the Northern Ranchlands over the next
few hours across the western portions of the CWA, before the
northeastern edge of the front catches up as the upper level low
dragging the front continues to pull away across the mid
Mississippi Valley. We have yet to see any precip
materialize...most likely do to the dry and capped mid layers as
evident in this morning`s sounding...however a few showers or an
isolated storm is possible late this afternoon or early evening
along the FROPA.
Precip chances will actually be slight better after nightfall with
the passage of the 850mb front. This may spark of some convection,
but at that point it will be elevated. Again, the mid levels may
be too dry and stable to support any growth.
Any precip that does form will be gone by the morning on Sunday
with clouds quickly clearing from north to south by the afternoon.
As far as temps go, readings will fall as the front sweeps through
and have made adjustments to the timing tonight. A much cooler day
is expected and Sunday with lower dewpoints. With the more
pleasant conditions some folks may head to the beach, however
waves will still be high, and there is going to be at least a
moderate risk of rip currents...or possibly even high.
LONG TERM (Monday through Saturday): No significant changes made
to the long term period as high pressure aloft and at the surface
will be in control of the weather. Monday will be an excellent
spring day across Deep South Texas with morning lows still in the
50s, but dry air and plenty of sunshine will allow readings to
rebound quickly. On tuesday, a short wave will quickly traverse
the region, but will little to no moisture available, only expect
some increasing clouds with no rain. In fact, rain-free conditions
are expected through the end of the week, with temperatures
warming rapidly. Models are still in fairly good agreement, with
dryline intrusions across the at least the western portions of the
CWA through much of the week. This will keep high temps across
the Western Ranchlands and Mid/Upper Valley areas to see readings
form 100 to 103...or possible even higher.
Now through Wednesday Night: The passage of a cold front later
today will bring strong northerly winds to the Lower Texas
Coastal waters this evening. Meanwhile, surface high pressure
will quickly build into the region overnight, keeping the surface
pressure gradient tight through at least Sunday afternoon. Seas
will build in response to the frontal passage and the strong
gradient...with wave heights of 5 to 8 feet or higher. Small Craft
Advisories are in effect for both the Laguna Madre for winds and
the Gulf Water for winds and seas until 7 AM. But, have extended
the SCA for the Gulf Waters east of Padre Island until Sunday
afternoon. Seas and winds should subside as the gradient relaxes.
For Monday and much of Tuesday, light winds and low seas are
expected. However, by Tuesday night and into Wednesday the
pressure gradient will strengthen and SCEC or low-end SCAs maybe
GM...Small Craft Advisory for winds until 7 AM CDT this morning for
Small Craft Advisory until 1 PM CDT this afternoon for GMZ150-
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