Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 201003 CCA
AFDBRO

Area Forecast Discussion...CORRECTED
National Weather Service BROWNSVILLE TX
403 AM CST Fri Jan 20 2017

.SHORT TERM (Today through Saturday): Fog is somewhat sporadic this
morning with areas of dense fog being mostly observed over the
Northern and Western Ranchlands. Boundary layer winds have been a
little stronger then is optimal with some of these stronger winds
reaching the surface at times mixing up the fog. In contrast, weak
surface troughing is developing with the approach of an upper trough
adding to slightly higher moisture convergence leading to the patchy
areas of dense fog. Will not issue a dense fog advisory due to the
fluctuating conditions but will continue to monitor through the
morning.

The approach of the upper trough and jet allows for a bump in
surface moisture and convergence along the developing surface trough
which will extend north to south across the eastern third of the
CWA. This will continue to provide a slight chance of convection
late morning into the afternoon. Best chances still remain over the
Northeast where the better convergence exist. Out west a dry line
will be slowly moving east with winds veering southwest and
conditions starting to dry out with the lower clouds lifting and
dissipating as the overrunning pattern weakens. Temperatures will
begin warm but will be tricky especially in the east depending on
how fast and if clouds break. Have lowered Max Temps in the east
due to the latter thinking.

Tonight...residual low level moisture, light winds, and absence of
lower clouds initially and a surface inversion should lead to
another round of fog. Will be leaning towards areas of dense fog
with the possibility of a dense fog advisory before the anticipated
drier air makes its entrance Saturday. Temperatures look to be a few
degrees cooler overnight with slightly lower dewpoints and a more
offshore component of the wind.

Saturday...A well organized storm system will be developing rapidly
with a strengthening mid and upper level trough over the Rockies
combining with a deepening surface low over the Southern Plains.
This will deeply stacked low pressure area passes well to the north
of the Deep South Texas.  Southwest to west to northwest winds are
expected in our areas will allow for surface dew points to lower and
temperatures to rise. Bumped up temperatures a few more degrees with
record temperatures likely to be challenged and broken.  Not
anticipating any elevated fire weather concerns with winds still
expected to be light even with relative humidity crashing in the
afternoon as dewpoints fall and temperatures rise. Will continue to
monitor out west for any stronger downslope winds with a small
probability of a red flag warning but a more likely chance of a
fire danger statement being issued.


.LONG TERM (Saturday Night through Thursday):
With the stacked low progressing eastward from OK to AR Sunday
morning, strong northwest winds will develop just after sunrise.
All models are noting a 100+ knot jet between H2 and H3, with good
mixing down to the surface. This will also pull significant dry
air downward, with humidity values below 20 percent for all areas
expect the immediate coast. A Fire Weather Watch is already posted
for Sunday, and a Wind Advisory is likely as well. The northwest
flow will also lead to a cooler day, with highs around 80. Monday
will be a much calmer day as surface high pressure moves into
Texas. Winds will be light and variable, while continued dry air
will bring nearly clear skies the entire day. The ridge shifts
east Monday night, with southerly flow returning for Tuesday. The
next area of low pressure develops across the central plains,
dragging a much weaker cold front across Texas Tuesday. This will
bring early day highs in the 70s, but temps will likely hover in
the mid 60s through the afternoon, and again on Thursday.

&&

.MARINE:
Today through Saturday: Light onshore winds and a slight sea to
persist today with a weak surface trough developing near or just
west of the coast. Light to moderate Offshore flow continues
Saturday as large low pressure system developing over North Texas
and Oklahoma passes to the east. Short fetch along with the
lighter winds should result in a slight sea. Patchy marine fog may
impact the Laguna and near shore waters this morning and early
Saturday.

Sunday through Tuesday: Gale Watch has been hoisted for the cold
front passage early Sunday morning, as winds reaching around 30
knots, with numerous gusts reaching 40 knots. Winds will finally
drop below 20 knots around midnight Sunday night, while seas will
finally drop below 7 feet by sunrise Monday. Winds will be
shifting slowly to the south on Monday, but will remain generally
around 5kts. Gusty south winds are forecast to develop on Tuesday
due to inflow into the next system developing across the Central
Plains. Small Craft Advisories may be needed Tuesday afternoon for
the Gulf waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  75  63  87  61 /  20   0   0  10
BROWNSVILLE          78  63  89  61 /  20   0   0  10
HARLINGEN            79  62  91  58 /  20   0   0  10
MCALLEN              83  61  93  59 /  10   0   0   0
RIO GRANDE CITY      83  57  93  57 /   0   0   0   0
SOUTH PADRE ISLAND   72  64  76  62 /  20   0   0  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Fire Weather Watch from Sunday morning through Sunday afternoon
     for TXZ248>257.

     Dense Fog Advisory until 9 AM CST this morning for TXZ248>250.

GM...Gale Watch from late Saturday night through Sunday evening for
     GMZ130-132-135-150-155-170-175.

&&

$$

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