Area Forecast Discussion
Issued by NWS Brownsville, TX
FXUS64 KBRO 301130 AAA
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
630 AM CDT Thu Mar 30 2017
.DISCUSSION...Updated for latest aviation discussion below.
.AVIATION...Satellite images and surface observations indicate
some low clouds across the coastal sections of the CWA with high
clouds across the rest of the CWA. Ceilings were near 1300ft at
KPIL. Visibilities were near 6SM with fog at KPIL. Expect VFR
conditions to prevail across the Rio Grande valley and northern
ranchlands today as high pressure builds into the area in the wake
of a weak cold front moving through extreme southeast portions of
the CWA this morning.
.PREV DISCUSSION... /issued 404 AM CDT Thu Mar 30 2017/
SHORT TERM (Today through Friday): A weak cold front will move
through the CWA this morning reinforcing the drier air across the
western portions as well as bring slightly cooler air into the
area as high pressure builds across deep south Texas in the wake
of the front. Isolated convection across northeast Mexico may
approach the extreme southeast portions of the CWA this morning
before the front moves through but rain chances will be confined
to offshore waters of the lower TX coast this morning.
Temperatures will be near normal this afternoon and tonight before
returning to above normal Friday as the surface ridge moves
eastward and low pressure develops across west TX Friday. Some
patchy fog may develop across the lower Rio Grande valley late
tonight into early Friday morning.
LONG TERM (Friday Night through Wednesday): Models remain
consistent with the local effects of the next large H5 trough
sweeping across the US. Models still show that although midlevel
forcing will be considerable, a punch of dry air will wrap into
the region beforehand, quickly strengthening the capping
inversion. There may be just enough moisture in the northern
ranchlands Sunday to spark a few showers, but steering flow would
direct them quickly to the northeast, with minimal accumulation.
Once this trough departs, H5 ridge returns quickly for Monday and
Tuesday, before the next fast-moving trough sweeps out of the
Rockies. Highs will remain above normal through the period,
reaching the low to mid 90s each afternoon.
MARINE: Today through Friday: Seas were near 7 feet with east-
southeast winds near 2 knots at buoy020 early this morning. Winds
will shift to the northwest and increase across the coastal waters
this morning as a weak cold front moves offshore the lower TX
coast. Will go ahead and issue a small craft advisory for the
Laguna Madre this morning through this afternoon and for the
offshore waters this morning through this evening as strong
northwest winds develop this morning in the wake of the front.
Winds and seas will gradually diminish this afternoon as high
pressure settles across deep south Texas. This will allow the
pressure gradient to weaken across the lower TX coast this
afternoon. Light to moderate north winds this afternoon will veer
to the east and diminish tonight as the surface ridge moves
eastward across the western Gulf of Mexico. Winds will veer to the
south and increase Friday as low pressure develops across west TX
and high pressure over the western Gulf moves eastward allowing
the pressure gradient to increase across the lower TX coast.
Saturday through Monday: Southeast flow will gradually decrease
over the weekend as a weak front drifts into the northwest Gulf.
Winds will be generally in the 10 to 15 knots range. Seas will
remain agitated on Saturday, reaching near 7 feet offshore.
Improved conditions expected Sunday as the front drifts through,
with winds shifting to the north around 10 knots, allowing seas to
decrease to 4 to 5 feet in the afternoon. Winds will be lighter
and variable on Monday as the southeasterly flow slowly returns to
the region. The lighter winds will reduce the effects of the Gulf
waves, which will decrease to 2 to 3 feet.
GM...Small Craft Advisory for winds until 1 PM CDT this afternoon for
Small Craft Advisory until 7 PM CDT this evening for GMZ150-155-
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