Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
411
FXUS64 KHGX 240250
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
950 PM CDT Sun Jul 23 2017

.UPDATE...
Convection continues to dissipate this evening across portions of
the Piney Woods region and expect mostly dry conditions to persist
through the remainder of the evening hours. However, rain chances
for the overnight period remain a little more uncertain.

Surface analysis shows a southward surging outflow boundary that
has crossed the Red River into North Texas, with thunderstorms
congealing along this outflow. Pressure rises behind it are not
terribly impressive, but the thunderstorms developing along the
boundary may support continued maintenance of the cold pool and
allow it to reach Southeast Texas in the pre-dawn hours. High
resolution guidance has not been terribly excited about overnight
rain potential so far this evening, but the latest (01Z) run of
the HRRR has begun to indicate a few showers (or maybe a storm)
may be able to develop across parts of the Brazos Valley during
the early morning hours. Whether or not this is actually from the
outflow (or another more subtle boundary already located across
the Brazos Valley... where interestingly Hearne has a light
northerly wind and College Station has a southerly wind,
indicating some weak surface convergence) remains to be seen. As a
result, have readjusted rain chances to include 20 PoPs generally
north of a Brenham to Cleveland line to account for uncertainty
with the evolution of the outflow boundary (and potentially
others).

Otherwise south to southwest winds 5-15 MPH tonight and partly
cloudy skies should keep overnight lows warm again in the mid 70s
to mid 80s.

Huffman

&&

.PREV DISCUSSION... /ISSUED 637 PM CDT Sun Jul 23 2017/

AVIATION...
A few shra/tsra will be possible over northern TAF sites through
03z before all of the precip comes to an end with the loss of
daytime heating. Fcst soundings show high clouds hanging around
for much of the night and into Monday. Fcst soundings also showing
little in the way of saturation on Monday and warmer convective
temps so will not mention precip in any of the TAFs on Monday.
S-SW winds will not fully decouple tonight and will likely remain
moderate on Monday. Could get some brief MVFR cigs Monday morning
at northern TAF sites between 13-16z but dry air aloft should mix
to the surface quickly and clouds will scatter out by mid morning
leaving VFR conds for the rest of the day. 43

PREV DISCUSSION... /ISSUED 401 PM CDT Sun Jul 23 2017/

DISCUSSION...
Coverage so far today has been generally north of I-10 and along
and east of I-45. Still not ruling out some isolated development
over the far NW counties through the early evening hours, but the
bulk of the storms will likely remain over the central zones of SE
TX.

With the upper low near the TX/LA border continuing to weaken tonight,
the ridge aloft out west will begin to build into the area
tomorrow. Slightly less coverage is expected tomorrow and Tuesday
as a result...with a corresponding bump up of daytime high temps.
Would not be too surprised to see a few 100s at some of our sites
with heat indicies 105-108 for most locations these next couple
of days.

Slightly deeper moisture progged to move in from the Gulf on Weds
and scattered POPS (closer to the coast) will be possible. A return
of mostly daytime seabreeze induced activity expected for the
rest of the week. As for the extended forecast...models appear to
be hinting that we might possibly see the passage of a very weak
front. Will likely just leave lowish POPS in for the weekend and
hope later runs add a bit more clarity. 41

MARINE...
Showers and storms have been largely suppressed over our waters
today as the bulk of today`s activity is either over land, or tucked
closer to the upper disturbance off the SW Louisiana coast. Water
vapor imagery shows that disturbance drifting westward, so parts of
the waters off the upper Texas coast can likely look to see activity
increase this afternoon and evening.

Winds have not really come down significantly today, and so continue
the SCEC through the night, as winds should stay up overnight. Of
course, winds and waves can be expected to be even higher near any
thunderstorms. Winds should gradually diminish and veer slightly as
surface high pressure moves over the area. Along with that, waves
should also slowly diminish from 2-4 feet to 1-3 feet. Relatively
persistent onshore flow should keep tides running several inches
above astronomical levels through the week, but should be well shy
of tide levels associated with causing flooding issues.

Luchs

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      77  98  76  97  78 /  20  20  10  10  10
Houston (IAH)              78  95  77  93  78 /  20  20  10  10  10
Galveston (GLS)            83  90  83  90  82 /  20  10  10  10  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 7 AM CDT Monday for the following
     zones: Brazoria...Chambers...Galveston.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 5 AM CDT Monday 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...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.

&&

$$

Discussion...14



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.