Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 201002
AFDBRO

Area Forecast Discussion
National Weather Service BROWNSVILLE TX
402 AM CST Fri Jan 20 2017

.SHORT TERM (Today through Saturday): A 500mb low pressure system
continues to move eastward across the Central Plains with a trough
axis passing through Deep South Texas this afternoon. Visible
satellite imagery indicates continued overcast skies east of Highway
281 with widespread clearing behind the line. Differential heating
has led to temperatures nearing 80 degrees in the Upper Valley and
only mid 60s in the Lower Valley this afternoon. Models are in
general agreement that clearing will continue from west to east this
afternoon. Tonight, the main concerns will be the possibility of fog
developing after midnight, especially along Highway 281 where rain
fell last and this morning. Model soundings continue to show a
strong temperature inversion with a moist layer near the surface and
subsidence moving in aloft. This, combined with light and variable
winds expected overnight, low clouds and patchy dense fog will be a
good possibility.

Friday, a shortwave impulse rotating around the trough may provide
one more chance of rain after 12Z, but there is some uncertainty due
to the lack of moisture available. Have kept POPs mainly to the
northern areas with and over the Gulf of Mexico. Temperatures will
warm up into the lower 80s along the Rio Grande with light S/SW
winds and less cloud cover expected Friday afternoon.


.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 and variable winds will continue
across the marine areas overnight tonight with seas ranging from 2
to 3 feet in the Gulf waters. Winds will increase out of the
south Friday afternoon and evening as a storm system develops in
the Central Plains. A mid-level impulse moving overhead on Friday
may produce a few isolated showers over the Gulf.

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.

&&

$$

This product is also available on the web at:
HTTP://WEATHER.GOV/RGV

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