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145
FXUS64 KHGX 161437
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
937 AM CDT Mon Oct 16 2017

.DISCUSSION...
The surface high pressure was centered over Oklahoma at mid
morning. A combination of a tight surface pressure gradient and
cold air advection was causing gusty winds at the coast. Winds
were slightly higher on Galveston Island with the trajectory
across Galveston Bay. Since guidance continues to show the wind
potential through midday, extended the wind advisory for Galveston
through 1:00 PM. Will monitor winds over the next few hours to see
if the advisory needs to be extended further into the afternoon.

Also issued a rip current statement from conditions reported by
the Galveston Beach Patrol. This statement covers the coastal
counties through 6:00 PM.

40

&&

.PREV DISCUSSION... /ISSUED 635 AM CDT Mon Oct 16 2017/

AVIATION...
Skies this morning are mostly clear as indicated by GOES-16
satellite imagery. VFR conditions expected to prevail through the
TAF period across all terminals. Mainly a wind forecast in this
morning`s TAF package. Expecting an increase in wind speed and
wind gusts with the help of daytime mixing shortly after sunrise.
These winds should begin to lower by early afternoon, and
continue to fall going into the evening hours across all sites.
With high pressure building in from the northwest, expecting a
similar pattern with wind speeds again increasing after sunrise
Tuesday morning, as included in the IAH TAF.

Hathaway

PREV DISCUSSION... /ISSUED 400 AM CDT Mon Oct 16 2017/

DISCUSSION...
Breezy to windy conditions are in place across Southeast Texas
early this morning behind Sunday`s cold front, which is currently
stretching from Biloxi, Mississippi towards Tampico, Mexico. While
most of the region is generally seeing north to northeast winds
in the 10-20 MPH range this morning, much stronger winds are being
observed across coastal areas of Galveston County. The KHGX wind
profiler is showing 40-45 knot (45-50 MPH) winds between 1,000 and
3,000 feet of the surface this morning. As these winds move
across the warmer waters of Galveston Bay, which has water
temperatures in the lower 80s this morning, some of these winds
have been able to mix down to the surface. This has resulted in
winds gusts in the 30-40 MPH range across the coastal mainland of
Galveston County and along Galveston Island. As a result, have
issued a small Wind Advisory for Galveston County.

RAP forecast vertical wind profiles show these stronger winds
decreasing closer to 9-10 AM this morning and this, combined with
a relaxing pressure gradient as a surface high over Oklahoma
spreads eastward, should allow for winds to fall below advisory
criteria by mid-morning and the advisory may need to be cancelled
early based on trends. Otherwise, expect dry and cooler
conditions across the region today with downright pleasant high
temperatures in the mid to upper 70s under sunny skies.

Northwest flow aloft will keep dry pleasant weather around for
Tuesday, with jackets needed in the morning as lows fall into the
upper 40s to mid 50s inland and upper 50s to low 60s along the
coast. Highs are expected to warm into the mid 70s to near 80.
Shortwave ridging aloft becomes established across the region
Wednesday and Thursday as an upper trough reaches the Southern
Plains, promoting high temperatures in the low to mid 80s mid-
week. Return flow becomes established Thursday into Friday,
allowing rain chances to return to the coastal waters Thursday.
Isolated to scattered showers and thunderstorms are forecast to
spread inland Friday as moisture continues to stream into the
region and energy from the Southern Plains upper trough arrives.

Rain chances are expected to linger into the upcoming weekend as
another upper trough reaches the Southern Plains. The disturbance
is located approximately 400 miles east of the Kamchatka Peninsula
on GOES-15`s central Pacific infrared imagery early this morning
and is expected to reach the Gulf of Alaska by the middle of this
week before dropping towards the Pacific Northwest coast by the
end of the week. Medium range guidance is fairly consistent in the
evolution of this feature through this week, but begins to
dramatically diverge as it reaches the Southern Plains this
weekend. The 00Z deterministic GFS cuts this trough off over Texas
late next weekend/early next week, meandering it across the state
and resulting in several days of rain for the region next week as
a cold front slowly moves across the region. The 00Z European and
Canadian, on the other hand, keep this trough open for longer and
cut it off east of the state. These solutions would allow for the
cold front to quickly move across the region and dramatically
shorten the window for rain chances next week. Have low confidence
for the forecast Sunday and beyond as a result, but have begun to
introduce rain chances in the extended forecast. Rain chances and
temperatures in the extended will be largely dependent on the
evolution of the upper low and associated cold front.

Huffman

MARINE...
Moderate to strong winds are left behind in the wake of Sunday`s
cold front. Small Craft Advisories are currently in effect across
all waters, with winds between 20 to 25 knots. Seas in the far
offshore waters are between 6 to 8 feet and in the nearshore
waters between 4 to 7 feet. Winds will eventually decrease as we
move into late Monday morning. By 16Z Monday, winds begin to let
up but small craft should still exercise caution. Small craft
advisories for the near and offshore waters are expected to
continue into Monday afternoon. The nearshore waters should see
sustained wind speeds lower to 15 to 20 knots with frequent gusts
between 20 to 25 knots Monday afternoon. Advisories may need to be
extended through the early evening hours on Monday, based on
trends as the pressure gradient slackens.

Tides are currently running around normal to slightly above
normal. Seas will continue to lower Tuesday, as northeasterly
winds become easterly by Wednesday. A long easterly fetch will set
up across the Gulf of Mexico Thursday and will remain in place
through the weekend. Seas will reach at least 5 feet, occasionally
6 feet by Thursday. Therefore, still looking like elevated seas
and tides will be possible late this week.

Hathaway

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      77  49  78  49  82 /   0   0   0   0   0
Houston (IAH)              77  54  78  54  83 /   0   0   0   0   0
Galveston (GLS)            77  61  77  64  81 /   0   0   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 6 PM CDT this evening for the
     following zones: Brazoria...Chambers...Galveston...
     Matagorda.

     Wind Advisory until 1 PM CDT this afternoon for the following
     zones: Galveston.

GM...Small Craft Advisory until 11 AM CDT this morning for the
     following zones: Galveston Bay...Matagorda Bay.

     SMALL CRAFT SHOULD EXERCISE CAUTION until 4 PM CDT this
     afternoon for the following zones: Galveston Bay...
     Matagorda Bay.

     Small Craft Advisory until 4 PM CDT this afternoon 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...Waters from Freeport to the
     Matagorda Ship Channel from 20 to 60 NM...Waters from High
     Island to Freeport from 20 to 60 NM.

&&

$$

Discussion...40
Aviation/Marine...41