Small Craft Advisory 4, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
349 PM CST Thu Jan 11 2018

.DISCUSSION...
Band of showers and isolated thunderstorms ahead of the prefrontal
trough will be exiting the area to the east in the hour. Clearing
skies have allowed temps to climb into the 70s behind the trough
to the west. However, lingering moisture combined with lift and
cooling temps aloft in association with the approaching upper
trough has allowed scattered tstms to redevelop across portions of
the western CWA. This activity will also be moving eastward and
should be out the CWA around sunset. Can't rule out some hail in
the very isolated stronger cells.

Winds will quickly increase late in the afternoon and evening
hours and will leave the Wind Advisory in place. Strong gusts
30-45mph will be possible...especially along and west of I-45 and
in the coastal counties. Much colder temps will be filtering in
and wind chills between 17-27F will be common late tonight. Wind
speeds will slowly diminish late tonight, but remain breezy well
into the day Friday.

A reinforcing front will filter into the region on Saturday
allowing for dry and cold wx to persist through the weekend. A
good portion of the area will see freezing overnight temperatures
through Sunday night.

As high pressure moves eastward we'll see a brief return flow on
Monday ahead of the next strong cold front Monday night.
Quality of moisture return is questionable considering the short
duration of onshore winds, but both GFS & ECMWF bring some precip
with the fropa. 47

&&

.MARINE...
Wind and seas will quickly increase as the strong cold front which
has pushed across SE TX this afternoon, moves through the
northwestern Gulf waters. A Gale Warning remains in effect from 6 PM
this evening through noon Friday. Winds speeds will approach 25-30
kts in Matagorda and Galveston Bay, with winds gusting to around 35
kts. Matagorda Bay is more probable to see wind speeds in the higher
reaches within this range. In the near and offshore waters, wind
speeds will range from 30-35 kts gusting as high as 45 kts at times.
Rough seas can also be anticipated in the nearshore waters ranging
from 6-10 feet with occasionally higher seas of 11-13 feet. In the
offshore waters, seas will range between 10-15 feet with
occasionally seas as high as 18-19 feet. Therefore, dangerous
boating conditions will prevail through the overnight hours and into
Friday.

These strong northwesterly winds will impact the water levels in
Galveston Bay early Friday morning, and as a result a Low Level
Water Advisory has been issued. Water levels are still expected to
fall to 1.5-2.5 feet below normal. Winds will begin to turn out of
the north/northeast by early Saturday, with seas lowering to 3-5
feet. Gradually decreasing offshore winds and lowering seas are
expected over the weekend, but caution flags and advisories might
still be needed for portions of the marine zones through Saturday
afternoon or Saturday night. Sunday will bring easterly winds and
onshore flow will eventually prevail by Monday. Moderate east to
southeast winds can be expected the beginning of next week.

Hathaway

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      29  49  28  48  27 /  10   0   0   0   0
Houston (IAH)              34  50  30  51  29 /  10   0   0   0   0
Galveston (GLS)            38  48  37  51  36 /  20   0   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Wind Advisory until 3 AM CST Friday for the following zones:
     Austin...Brazos...Burleson...Colorado...Fort Bend...
     Grimes...Harris...Houston...Liberty...Madison...
     Montgomery...Polk...San Jacinto...Trinity...Walker...
     Waller...Washington...Wharton.

     Wind Advisory until noon CST Friday for the following zones:
     Brazoria...Chambers...Galveston...Jackson...Matagorda.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 PM CST this evening
     for the following zones: Coastal waters from Freeport to
     the Matagorda Ship Channel out 20 NM...Coastal waters from
     High Island to Freeport out 20 NM...Galveston Bay...
     Matagorda Bay...Waters from Freeport to the Matagorda Ship
     Channel from 20 to 60 NM...Waters from High Island to
     Freeport from 20 to 60 NM.

     Gale Warning until noon CST Friday for the following zones:
     Coastal waters from Freeport to the Matagorda Ship Channel
     out 20 NM...Coastal waters from High Island to Freeport out
     20 NM...Galveston Bay...Matagorda Bay...Waters from
     Freeport to the Matagorda Ship Channel from 20 to 60 NM...
     Waters from High Island to Freeport from 20 to 60 NM.

     Low Water Advisory from noon to 4 PM CST Friday for the
     following zones: Galveston Bay.

&&