Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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603
FXUS64 KHGX 262200
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
400 PM CST Sun Feb 26 2017

.DISCUSSION...
Dense high cloudiness atop lower cu cloud streets this afternoon
as temperatures have warmed into the lower 70s. Southwestern warm
and more moist air riding up and over the relatively cooler drier
surface dome of air providing just enough gentle lift along the
theta e surfaces to generate scattered light showers. Periods of
light rain will will occur through tomorrow afternoon. The passage
of a shortwave disturbance currently traveling into New Mexico
and into the northern TX tonight may generate enough lift over
central state to pop a few thunderstorms east of the I-35 corridor
that would move east to northeast. These evening storms may clip
the far northern counties of the forecast area...possibly with a
rogue strong cell or two latter tonight into early Monday morning.
If this shortwave can push parcels past a near 7-8H warm nose...there
would be ample CAPE (in tandem with an exiting 30-40 kt low level
jet) to set the stage for a more condusive strong convection
scenario. Again...low chances for thunderstorms to mainly pass
over the far northern counties generally north of a Brenham to
Huntsville to Livingston line during the overnight hours.

Mainly overcast and mild start to Monday morning with this
continued warm air advection pattern keeping slight to low end
rain chances in place over the northern CWA through the afternoon
hours. Middle to upper 60 dew point air riding over slightly
cooler shelf water in the middle 60s may allow maritime fog to
develop...confidence in patchy fog/haze around Galveston Island
and surrounding waters tonight. Despite the mostly cloudy and
showery conditions...warmer mid-level flow pulling in moist air
will equate to subsequent day warming back into the lower to
middle 80s the next couple of days. A relatively uneventful Monday
will lead to a stronger onshore wind day Tuesday...abnormally
warm and cloudy with slight shower chances over the far interior.
A passing northern CONUS upper trough will allow Rocky Mtn lee
pressure to lower...the associated cold front will travel across
the state early Wednesday. NWP has speed up the front from
previous runs and now has the boundary passing through during the
morning (daylight?) hours. Along or ahead of this front...mainly
showers with embedded storms. The faster 84 hr NAM has a stout cap
for the lift to contend with...the slower GFS has a more favorable
profile to tap into in producing more thunder. A fast mover of a
boundary so the main threats from any early Wednesday QLCS appears
to be strong winds.

The cool and dry backing air mass/High will scour out skies on
Thursday and regulate daily warmth to the near normal upper
60s...afternoon humidities to fall into the 20s/30s. A couple of
starry sky early mornings in the 40s Thursday and Friday. The next
system coming down the pike is progged to affect the region next
weekend. Broad low/open wave trough hanging back over western
Mexico will set the stage for the development of a lower Texas
coast surface trough. Better low level convergence and a disturbance
or two passing through within the southwesterly flow (per ECMWF)
has POPS up in the high end to likely category Sunday. 31

&&

.Marine...
Sustained winds over the Gulf remain near SCA criteria and will maintain
the SCA for the offshore waters through 03z and this may have to be
extended. Short term guidance is struggling a bit with winds and remain
too light. A moderate to occasionally strong onshore flow will persist
through Wednesday morning. Warm and moist air flowing over cooler shelf waters
will lead to periods of sea fog through Wednesday morning. Will carry patchy
sea fog for Galveston Bay and the adjacent Gulf waters through Tuesday night.

A cold front will cross the coastal waters on Wednesday and a strong offshore
flow will develop in the wake of the front. Surface high pressure will settle
over North Texas by Thursday morning and winds will veer to the northeast.
The high will shift east and a weak area of low pressure will develop over the
southern Gulf. This will allow for east winds to develop and strengthen to near
20 knots as the gradient tightens between the low to the south and the high to
the northeast. A prolonged period of east winds is expected Thursday night
through early Sunday morning. Tide levels will increase and tide values may
increase 1 to 2 feet above normal by Saturday night. 43

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      63  81  65  83  63 /  40  30  10  30  30
Houston (IAH)              66  82  66  84  70 /  30  30  10  20  20
Galveston (GLS)            68  76  67  78  69 /  20  30  10  10  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 9 PM CST this evening
     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.

     Small Craft Advisory until 9 PM CST this evening 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.

&&

$$

Discussion...31



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