Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 281139
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
639 AM CDT Tue Mar 28 2017

.AVIATION.../12Z TAF/
Ceilings range from VFR along the coast to MVFR over Houston
terminals and then IFR/LIFR for KCXO/KUTS/KCLL. The GOES 16
difference channel of 3.9-11 micron really does a great job
showing these low ceilings across the area. Based on this imagery,
ceilings should begin to improve the next couple of hours over
the Houston area and points northward. VAD wind profile from the
KHGX 88D only shows 15-25 knots in the lowest levels, but those
winds should increase during the day. This will also allow for
some gusts near 25 knots this afternoon with good mixing. Ceilings
should lift to VFR for most areas but then are expected to
decrease in the evening. A 40-50kt LLJ should maintain strong
winds overnight as ceilings become MVFR again. Wednesday should be
a messy day for aviation given the forecast for widespread
convection. TAFs have VCSH starting at 09Z but look for VCTS/TSRA
beginning late morning Wednesday through the afternoon in future
TAF updates.

Overpeck

&&

.PREV DISCUSSION... /ISSUED 402 AM CDT Tue Mar 28 2017/

DISCUSSION...
A progressive upper air pattern will bring a couple of stormy
episodes across Southeast Texas over the next seven days. The
first will begin late tonight through Thursday and the second will
occur over the weekend and into Monday night of the upcoming week.
Both systems will bring slight chances for at least isolated
strong thunderstorms to Southeast Texas.

The 06Z NamBufr forecast soundings show a fairly large cap over
the area tonight and early Wednesday morning. Even though this cap
should erode as the upper level storm system moves into the state,
the forecast soundings still showed somewhat of a capping
inversion in place over the southern half of the forecast area on
Wednesday and Wednesday night. A strong low-level jet will
develop overhead and help provide strong wind shear ahead of the
main area of storms. The latest Nam12, GFS, and ECMWF all show
better chances for strong storms over the northern half of the
area mainly Wednesday and Wednesday evening. The Storm Prediction
Center as of 3:30 AM had best chances for severe potential
generally along and east of a line from Madisonville to Tomball
and north of a line from Tomball to Cleveland. PWs are forecast to
reach to around 1.7 inches, indicating the potential for at least
locally heavy rainfall.

Following this system, high pressure will bring a brief warm and
dry period Thursday night through Friday night. The next storm
system will then move across the state from late Saturday through
early Monday. Again looking at widespread rain and thunderstorms
with slight chances for isolated strong or severe storms Sunday
and Sunday night. Locally heavy rainfall also again appears to be
possible, especially in the ECMWF solution with a surface low
moving up the coastal plain.

40

MARINE...
Moderate southerly winds this morning are expected to increase to
around 20 knots in offshore areas of the Upper Texas Coast later
this afternoon and tonight. Winds should reach 20 to 25 knots
tonight with seas building to rough levels. A small craft advisory
will be issued for these areas for this afternoon and tonight. Winds
and seas gradually decrease Wednesday into Thursday. Thursday
offshore winds develop which will allow for seas to decrease further
for the end of the week. Southerly winds develop again over the
weekend.

Tide levels are about a half foot above normal and will likely
remain elevated for the next couple of days. Offshore winds on
Thursday into Friday may push tides lower.

Overpeck

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      85  69  79  59  75 /  10  50  80  30  10
Houston (IAH)              85  71  84  67  80 /  10  20  80  50  30
Galveston (GLS)            79  72  77  70  77 /  10  10  60  50  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION from 4 PM CDT this afternoon
     through Wednesday morning for the following zones:
     Galveston Bay...Matagorda Bay.

     Small Craft Advisory from 4 PM this afternoon to 10 AM CDT
     Wednesday 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...Waters from
     Freeport to the Matagorda Ship Channel from 20 to 60 NM...
     Waters from High Island to Freeport from 20 to 60 NM.

&&

$$

Discussion...40
Aviation/Marine...39


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