Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 201011
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
411 AM CST Sat Jan 20 2018

.DISCUSSION...
Foggy conditions persist across the region. So far visibilities
have remained just above dense fog advsy criteria, but suspect we
may need to issue one in the not too distant future as a downward
trend is expected into sunrise. With the exception of sea fog,
inland visibilities should improve toward mid morning.

The ongoing forecast is in pretty good shape and very few changes
were made. The upper trough axis continues to slowly move
eastward and away from the region. The bulk of precipitation will
follow, however we still anticipate some iso/sct warm air advection
type showers throughout the day and into Sunday. Sea fog will
be expanding through the day across the nearshore waters and
spread inland again this evening and overnight.

The next front is forecast to move across the region between roughly
midnight-7am Monday. Look for a band of showers/tstms to develop
along this boundary late Sunday afternoon across ncntl Texas with
the approach of the upper trough and a 35-40kt llvl jet feeding
Gulf moisture into the boundary. In regards to strong/severe wx
potential: it still appears best dynamics with this system will
be situated north & northeast of our CWA. With marginal instability
(skinny CAPES <600 j/kg, LI`s -2 to -4, etc) can`t totally rule
out an isolated stronger cell or two across the northern parts of
se Tx - maybe in the form of gusty winds as the line passes.

Clearing skies and seasonable wx should prevail in the wake of the
front...likely persisting for the majority of the work week with
a reinforcing front and dry airmass expected to move in toward
midweek.  47

&&

.MARINE...
Despite the coastal trough begins moving east of the area today, we
will likely continue to see slightly elevated winds/seas across the
offshore waters. Did keep an SCEC up for this area through the aft-
ernoon hours. Otherwise, conditions should remain favorable for the
development of fog/sea fog the next day or so. A persistent onshore
flow along with increasing low-level moisture will help to keep the
pattern in place until the next cold front sweeps into the bays and
coastal waters. Latest model runs are just a touch slower with this
boundary but we should see strong north winds over the marine areas
Mon morning/afternoon. SCEC/SCA will be possible. Scattered showers
and isolated thunderstorms are possible with frontal passage. East-
erly winds to return by Tues (as the associated surface high drifts
slowly across the southern states)...and linger through the rest of
the week. 41

&&

.AVIATION...
Messy messy TAF forecast will continue as we deal with precipitation
associated with the coastal trough and increased low-level moisture.
Will likely keep with a mix of IFR/MVFR CIGS through this afternoon,
evening as VIS issues improve. The return of lower CIGS/VIS expected
tonight/early Sun morning as the onshore flow persists. Sea fog will
continue to be a threat for GLS. 41

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      69  62  74  47  65 /  20  20  60  70   0
Houston (IAH)              70  62  75  55  67 /  30  20  40  70   0
Galveston (GLS)            66  61  69  56  65 /  30  20  20  60  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...Dense Fog Advisory until 10 AM CST this morning for the
     following zones: Galveston Bay...Matagorda Bay.

     SMALL CRAFT SHOULD EXERCISE CAUTION until 4 AM CST early this
     morning 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.

     Small Craft Advisory until 4 AM CST early this morning for the
     following zones: Waters from Freeport to the Matagorda Ship
     Channel from 20 to 60 NM...Waters from High Island to
     Freeport from 20 to 60 NM.

     SMALL CRAFT SHOULD EXERCISE CAUTION through this afternoon for
     the following zones: Waters from Freeport to the Matagorda
     Ship Channel from 20 to 60 NM...Waters from High Island to
     Freeport from 20 to 60 NM.

&&

$$


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