Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 180104
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
704 PM CST Sat Nov 17 2018


.AVIATION...
Dry air still holding on over the eastern areas but this is
changing with weak upglide producing a SCT/BKN deck around
3500-6000ft. Richer moisture streaming northward across the far
Western Gulf and into the PSX area this evening as cold front
noses in through SPS-LBB area at 00z. The cold front will continue
to march southward then begin to slow Sunday morning. This should
bring the front into the CLL area 12-15z. Expecting light rain to
develop over the region Sunday with scattered showers mainly along
and elevated in the wake of the front. A narrow axis of deeper
moisture and weak instability will probably support a smattering
of thunderstorms from near CLL down to SGR to PSX. The front will
push south throughout the day with the mix of VFR/MVFR skies
abruptly becoming solid MVFR in the 1000-1800ft range with
the FROPA. Will carry VCSH transitioning to RA for most sites
though CLL/SGR/GLS will be looking for VCTS.

Improvement in MVFR/IFR ceilings isn`t likely for IAH/HOU area
until Monday evening when low level dry air infiltrates.
45

&&

.PREV DISCUSSION... /ISSUED 220 PM CST Sat Nov 17 2018/

DISCUSSION...
Strato cumulus is increasing across the area this afternoon as
moisture levels gradually increase. Pleasant day with current temps
generally ranging from the upper 60s to mid 70s across the area.

Change is in the way for tomorrow as a cold front is expected to
enter NW portions of the area early on Sunday and reach GLS very
late in the day or in the evening. Showers are likely near and
also behind the front, especially across SW areas where the
deeper moisture will be present. Could see isolated thunderstorms
across southern areas. Temperatures are a challenge tomorrow as
they will fall behind the front. So, W/NW areas will see early
morning max temps, where SE areas will warm some ahead of the
front, but there will also be abundant cloud cover which will
limit that warming. The front is likely to stall in our coastal
waters on Sunday night/early Monday. Moisture levels are still
high in the wake of the shallow front and rain chances remain high
through Monday. A mid/upper disturbance moves across Monday night
and we will see drier air push through the area behind that
disturbance. That drier air will be short lived as moisture levels
and a coastal surface trough return by early Wednesday as another
mid/upper trough approaches. This sets the stage for more
widespread showers, especially across coastal and central areas.

Model guidance is in agreement that drier air will push in behind
the Wed/Wed night mid/upper trough, so am expecting a dry
Thanksgiving with temperatures warming into the 60s. Looks like
low rain chances and warmer temperatures for Fri/Sat as a zonal
mid-level flow pattern is at least briefly in place over SE
Texas. 33

MARINE...
A cold front over North Texas will push into SE TX by morning and then
slow considerably as a coastal trough begins to develop off the Middle
Texas coast. The cold front will eventually make it into the coastal
waters by early Monday morning and basically become stationary just off
the coast. Winds over the Bays will likely be NE in the wake of the
front but over the Gulf, winds will likely back to the E-NE in response
to the coastal trough. A SCEC may be required for parts of the coastal
waters Mon into Tuesday. Another coastal trough will develop on Wednesday
and this feature will evolve into a coastal low by Weds night. An SCA or
another SCEC will be possible Wed night into Thursday as the low moves
east and away from the region. The coastal troughs will generate periods
of showers and thunderstorms Sunday through Thursday and mariners should
prepare for occasionally higher winds and seas near storms.

The E-NE winds will give tides a boost upward but the the departure should
be 0.5-1.0 feet above normal and astronomical high tide isn`t really that
high so tide levels should remain under 2.5 feet.

Water temps have warmed slightly and dew points over the water will exceed
the water temps by 2-4 degrees. Not sure this will be enough to generate
sea fog but it is something to watch for beginning Sunday afternoon. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      55  56  45  52  43 /  20  60  50  60  20
Houston (IAH)              57  64  50  57  48 /  10  60  40  60  40
Galveston (GLS)            64  70  58  62  56 /  10  40  40  70  50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

Discussion...41
Aviation/Marine...45



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