Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 211548
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
948 AM CST Tue Feb 21 2017

.DISCUSSION...
Mid/upper level low is moving eastward into Louisiana this morning.
Some clouds on the back side of the low across parts of mainly the
eastern half of our area will continue to erode and move out of the
here during the day today and will bring a majority of the area mostly
sunny to sunny skies. Look for this afternoon`s high temperatures to
warm into the lower to mid 70s, which is a lot cooler than this date
back in 1996 when College Station set their all-time high temperature
for February when it reached 99 degrees.  42
&&

.PREV DISCUSSION... /ISSUED 526 AM CST Tue Feb 21 2017/

AVIATION...
Main issue this morning has been fog and then visibility
improving. Water vapor imagery shows upper low moving past the
area with a few showers to the east and northeast of KIAH to KUTS.
MVFR ceilings remain over KCXO/KUTS/KCLL with some patchy fog
south of those areas over the Houston terminals. Dense fog has
dissipated so may only see 4-6SM visibility through the next few
hours of the morning. A frontal boundary should push through
allowing for NW winds today and clearing skies. Winds overnight
should remain around 5 knots which should keep fog from forming
again for Wednesday morning. Model guidance still hints at fog but
still looking at 20 knots of wind around 925mb that could keep
boundary layer mixed.

Overpeck

PREV DISCUSSION... /ISSUED 448 AM CST Tue Feb 21 2017/

UPDATE...
Patchy fog has lifted for the most part by 4:30 AM across the
advisory area. For this reason, canceled the dense fog advisory.
However, still may see some isolated patches of fog through sun
rise.

Also tweaked the weather type. Isolated thunderstorms were
developing in the vicinity of the upper low over NE Texas. Some of
these may move into the far northern counties of the forecast area
this morning.

40

PREV DISCUSSION... /ISSUED 332 AM CST Tue Feb 21 2017/

DISCUSSION...
An upper low will move across the Red River Valley into the lower
Mississippi Valley today with an upper trough moving over SE
Texas this morning. As the system moves overhead, isolated rain
showers will be possible this morning. Patchy fog will also affect
portions of the area. Guidance and model data lifts the fog before
mid morning. Issued a dense fog advisory for Liberty, Chambers,
Harris, Galveston, and Brazoria through 7:00 AM. However, will
adjust the advisory if needed.

An upper ridge will then develop over the state later this
afternoon and tonight. Daytime temperatures will then become the
main item of concern and highs from Wednesday through Friday will
reach into the upper 70s to lower 80s.

Another upper level system will move across the northern plains
late this week with a frontal boundary expected to move across SE
Texas on Friday. Both the GFS and ECMWF moves off of the coast
sometime during the evening. A model consensus does not develop
rainfall along this front until it moves well offshore Saturday
morning. Onshore winds will develop by Sunday. Good moist and warm
air advection off of the Gulf will help to return rain chances by
Monday.

40

MARINE...
Rainfall yesterday over much of the coast has allowed for some
patchy fog to develop. Fog has developed over Galveston Bay and
parts of the Houston Ship Channel so will issue a dense fog advisory
through the morning hours. A front will push off the coast from 7AM
to 11AM this morning which should end any fog as winds increase.
Winds may reach advisory criteria this morning from Freeport to
Matagorda bay out 60nm so small craft advisories will be posted
along with exercise caution for areas from Freeport to High Island.
Winds should decrease this afternoon and seas should build to near 7
feet in offshore waters.

Low winds and seas will continue after today through the end of the
week. A cold front should push off the coast Friday night into
Saturday allowing for increased NE winds. Advisories may be needed
Saturday for strong NE winds in the offshore waters of the Upper
Texas Coast. Seas should build in response and reach 5 to 7 feet in
the offshore areas.

Tide levels remain elevated around a half foot to a foot above MLLW.
Levels should gradually decrease today as NW winds develop in wake
of a frontal passage.

Overpeck

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      75  52  80  55  82 /  10   0   0   0   0
Houston (IAH)              75  56  79  56  81 /  10   0   0   0   0
Galveston (GLS)            71  60  71  62  72 /  10   0   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...Small Craft Advisory until noon CST today for the following
     zones: Coastal waters from Freeport to the Matagorda Ship
     Channel out 20 NM...Matagorda Bay.

     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...Matagorda Bay.

     SMALL CRAFT SHOULD EXERCISE CAUTION until noon CST today for the
     following zones: Coastal waters from High Island to
     Freeport out 20 NM...Galveston Bay...Waters from High
     Island to Freeport from 20 to 60 NM.

     Small Craft Advisory until 6 PM CST this evening for the
     following zones: Waters from Freeport to the Matagorda Ship
     Channel from 20 to 60 NM.

&&

$$


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