Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 140239
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
939 PM CDT Sun Aug 13 2017

.UPDATE...
Forecast appears to be on track this evening, only minor changes
to account for observations and radar trends. Went ahead and
lowered PoPs for this evening and overnight period as the precip
that could have moved through the NE zones of the CWA,
specifically in Houston County, stayed east of the area.

Going to hold off on issuing a heat advisory for tomorrow to allow
the next shift to look at the 00Z guidance. Regardless, tomorrow
looks to be similar to what we saw today. Our coastal counties and
second tier counties inland could see heat indices ranging
between 105-109 degrees tomorrow afternoon. Therefore, big story
for tomorrow will once again be the heat. Do your best to stay
cool by staying hydrated and limiting your exposure to direct
sunlight especially during the hottest times of the day.

Hathaway

&&

.PREV DISCUSSION... /ISSUED 720 PM CDT Sun Aug 13 2017/

AVIATION...
Quiet radar this evening. The eastern passage of a shortwave
disturbance across northeastern Texas is currently sparking
convection about 75 miles northeast of UTS this evening. Short
range high resolution models keep this activity well off to the
northeast and dissipate it across northern Louisiana Monday
morning. 3-5 hours of near sunrise lower MVFR decks across the
northern hubs...VFR elsewhere. Persistent southwest becoming
southerly flow wind pattern with few-sct VFR cu field forming
from 14 through 18Z. Surge of slightly higher moisture moving in
from the western Gulf along and behind the inland-advancing sea
breeze boundary has VCSH in around metro during the mid to late
afternoon hours. 31

PREV DISCUSSION... /ISSUED 347 PM CDT Sun Aug 13 2017/

DISCUSSION...
A few showers and thunderstorms possible across the far northern
areas this afternoon as an upper disturbance moves through.

Hot weather will be the norm this week as high pressure tends to
dominate our weather pattern. Afternoon temperatures climbing to
the mid to upper 90s each afternoon inland will combine with the
onshore flow of moisture to boost the heat index into the 103-109
degree range. Slightly cooler conditions may develop Saturday as
ridging may weaken.

Galveston got to 111 heat index earlier this afternoon with other
inland sites 103 to 108 at 3 pm. Another heat advisory may be
needed again for Monday. Tuesday and Wednesday could be slightly
cooler if showers and thunderstorms develop across the southern
areas as depth of richer low level moisture increases on slightly
stronger southerly flow (and mixing). Rain chance still look
relatively low in the 20-40 percent range Tue and Wed.

Guidances in general is consistent with ridging remaining over the
area and then by Saturday diverge with the placement and strength
of the ridge. ECMWF breaks down the western end of the ridge over
CA/NV/AZ maintaining the ridging over AZ/TX which could allow for
greater rain chances and cooler weather...while the GFS solution
slides the ridge eastward parking it overhead which would maintain
the heat and lower rain chances. Currently favoring the GFS
solution with low pops and continued above normal temperatures and
unfortunately heat index readings.

Tropics...
Newly upgraded tropical storm Gert recurves over the Atlantic and
poses no threat to SETX. Another tropical disturbance in the east
central Atlantic is forecast to move west and could become an
issue for the Gulf or Western Sargasso Sea a week from
Wednesday...so still way to early to do anything other than
monitor it.
45

MARINE...
An increasing pressure gradient between Gulf high pressure and
Plains low pressure will boost wind speeds tonight and into the
midweek. Each night, expect caution level winds for small craft to
be reached, with gradually building waves following behind. In the
back half of the week, the high will gradually come more into
control, allowing winds to modestly diminish. As the Gulf high
wobbles about through the week, as well as with subtle diurnal
effects, the winds may vary from southeasterly to southwesterly, but
that base southerly state will be persistent. This persistence will
help keep tides above astronomical norms by roughly half a foot.

Luchs

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      77  98  77  97  78 /  10  10   0  10   0
Houston (IAH)              79  96  79  95  79 /  10  10  10  30  10
Galveston (GLS)            83  93  83  91  83 /  10  10  10  30  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION through Monday 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...Galveston Bay...Matagorda
     Bay...Waters from Freeport to the Matagorda Ship Channel
     from 20 to 60 NM...Waters from High Island to Freeport from
     20 to 60 NM.

&&

$$

Update...08



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