Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 182039

Area Forecast Discussion
National Weather Service Brownsville TX
239 PM CST Sun Nov 18 2018

.SHORT TERM (Tonight through Monday night): The cold front
continues to sweep southward across south Texas. It is accompanied
by a good 15 to 20 degrees temperatures drop with the initial
passage. The front should be into the HBV area within the next
hour or so, and should reach the MFE area 7 to 8 PM tonight. Final
arrival in the lower valley will be slowed, as weak troughing
already present will slow the eastward progression. The cold air
will probably not reach BRO until around midnight or so. Shower
activity will increase ahead of the front, aided by daytime
heating and forcing along the front. Most activity will remain
light, but a few claps of thunder may accompany any heavier
showers. As the coastal trough remains steady just offshore,
isentropic upglide will transition precipitation to light rain and
drizzle late tonight into tomorrow. Total accumulation will
remain light. Seeing how strong the cold air in the 50s is pushing
southward, feel the CAA will remain strong during the day Monday.
So along with the overcast conditions, temperatures will
generally remain steady in the upper 50s to around 60s areawide.
The trough slowly drifts out to sea overnight Monday night, so the
main rain chances shift further offshore, but the cloud cover
remains pretty dense through the night. This will keep diurnal
change minimal from Monday into Monday night.

.LONG TERM (Tuesday through Sunday): Surface high pressure over
Oklahoma supported by a mid level ridge over the Southwest will
maintain a tight gradient across the lower Texas coast, along
with a coastal trough. Most of the rain should stay over the Gulf,
but rain chances will continue along the coast. The trough will
remain stubbornly in place through Wednesday, with high pressure
shifting toward and over the Mississippi Valley. Rain amounts over
land areas should remain low. A shortwave trough will track
through the flow into the Texas Panhandle Wednesday, helping to
push surface high pressure farther east, which will veer winds
locally from north to northeast or east. Lower temperatures will
trend warmer Wednesday and Thursday, and especially through the
weekend, when they will be well into the 70s, pretty much normal
for this time of year. The tail end of a larger scale front will
push south into the area Friday, as another short wave trough
moves west to east across north Texas. A stronger, initially polar
source air mass will mix with a colder continental Canadian
source moving south out of the Plains, and will arrive late
Sunday, which will bring a cool down for Monday. Thursday will be
mostly cloudy with light north to northeast winds and a slight
chance of rain, mainly near the coast. High temperatures will be
from the 60s to lower 70s, from west to east.


Tonight through Monday night: Small Craft should exercise caution
today as southerly flow wraps into the approaching cold front.
Scattered to numerous showers will continue, with occasional
thunder still a possibility. The front will gradually sweep across
the Laguna Madre and immediate nearshore waters tonight, but will
be limited by develop coastal trough just offshore. This will keep
winds from strengthening considerably for most of the night. Winds
near 15 knots are still expected, but getting winds up to 20 knots
is not yet expected. The trough slowly drifts eastward through the
day Monday, gradually shifting the northerly winds further into
the Gulf waters. There may be a brief period later Monday evening
or night where northerly winds reach near 20 knots, but that
period will be brief before the surface high becomes dominant in
the northwest Gulf.

Tuesday through Friday night: North winds and associated seas
will remain slightly elevated Tuesday, suggesting small craft
should exercise caution conditions on the Gulf. This will be the
result of high pressure over Oklahoma coupling with lower pressure
out over the northwest Gulf, maintaining a coastal trough and a
tighter gradient over the lower Texas coastal waters. Winds will
shift to northeast and weaken some Tuesday night through Thursday
night even as the trough persists. The pattern will break down
later in the week when offshore low pressure gets absorbed by the
tail end of a larger scale Plains cold front moving out over the
northwest Gulf Friday and Friday night.


BAYVIEW/PORT ISABEL  59  61  56  65 /  60  50  40  30
BROWNSVILLE          58  61  55  66 /  60  50  40  20
HARLINGEN            56  60  53  65 /  50  40  40  20
MCALLEN              56  60  53  64 /  50  30  20  10
RIO GRANDE CITY      54  59  52  64 /  50  30  20  20
SOUTH PADRE ISLAND   62  65  61  66 /  60  50  50  30




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