Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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449
FXUS64 KHGX 201718
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1218 PM CDT Wed Sep 20 2017

.AVIATION...
Scattered showers and thunderstorms are already beginning to pop
up across the area and will likely persist throughout the
afternoon today. Another round of low ceilings and/or fog is
likely overnight tonight and into tomorrow morning, with the
highest chances generally north of KIAH. KCXO will likely again be
the hardest hit and may drop down to LIFR in the hours before and
around sunrise. Other terminals, if impacted, should expect MVFR
to occasionally IFR conditions during the early morning hours,
quickly lifting to VFR around mid to late morning. Scattered
showers and storms will also be possible once again tomorrow
afternoon.

11

&&

.PREV DISCUSSION... /ISSUED 943 AM CDT Wed Sep 20 2017/

DISCUSSION...
Expect most of the area to be partly cloudy today with temperatures
warming into the 90s (slightly above normal temperatures for this time
of the year). Already seeing some showers and thunderstorms near the
coast, and the area should see showers and thunderstorms to continue
to develop as the day progresses, with the greatest concentration
probably setting up generally along and to the east of I-45. Current
forecast has things covered, and only minor changes were made on the
morning update.  42


PREV DISCUSSION... /ISSUED 351 AM CDT Wed Sep 20 2017/

DISCUSSION...
The upper level shortwave ridge that moved over SE Texas yesterday
was now east of the area. A shortwave trough will be moving across
the forecast area today. Not a lot of activity has resulted so far
early this morning with this system. PWs over SE Texas ahead of
the shortwave were lower than 24 hours ago and ranged from about
1.7 to 1.9 inches. Model PW forecasts do not differ much from the
satellite derived PWs throughout the day today. The high
resolution models do indicate a potential for isolated to
scattered showers and thunderstorms.

The pattern aloft is still expected to develop into an upper
trough across LA into SE Texas with an upstream high pressure
ridge over N Texas into the Hill Country. This should translate
into isolated to scattered showers and thunderstorms mainly during
the daytime hours on Thursday and Friday. The upper level high
pressure ridge should then knock down the rain chances a bit;
although, a blend of the models still shows daily isolated
coverage. Do expect rain chances to increase beginning on Monday
as the main upper trough over the Rockies begins to slowly move
eastward into the Plains. As it does so, SE Texas should begin to
see an increase in moisture and warm air advection. In turn,
shortwave troughs moving ahead of the main trough will in help to
destabilize the airmass enough for scattered showers and
thunderstorms.

MARINE...
Persistent southeast winds across the Upper Texas Coast will
continue to support seas around 3 feet for the rest of the week
and into the weekend. Passing showers will be possible the next
couple of days but more so on Thursday with higher moisture over
the Gulf. Tide levels will be about a half foot to 1 foot above
normal especially along Gulf facing beaches and western portions
of Galveston Bay.

Overpeck

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      93  75  90  73  91 /  20   0  40  10  20
Houston (IAH)              92  77  90  75  91 /  40  10  40  20  20
Galveston (GLS)            89  80  86  79  87 /  20  20  30  20  20

&&

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

$$

Discussion...42
Aviation/Marine...11



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