Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 261125
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
625 AM CDT Sun Mar 26 2017

.AVIATION...
The latest forecast soundings show the potential for IFR/MVFR
through about 14Z this morning. As the low-level inversion begins
to lift and break, expect the ceilings to either scatter out, or
else to lift to all MVFR between 14Z and 17Z, and then to VFR
between 17Z and 22Z. MVFR conditions will then return by 03Z.
There is the possibility that IFR or lower conditions could
develop between 06Z and 09Z.

40

&&

.PREV DISCUSSION... /ISSUED 429 AM CDT Sun Mar 26 2017/

DISCUSSION...
Areas of fog have developed and at times the fog has become
locally dense. A Dense Fog Advisory may yet be required this
morning. Once the fog burns off later this morning, sunshine will
return to the region at least through the early afternoon but
clouds should return near the coast by mid afternoon. The
pressure gradient is weak this morning but really begins to
tighten by aftn. Breezy conds expected by afternoon with
occasional gusts above 25 mph possible. An upper level disturbance
will move across the southern plains tonight and early Monday. The
tail end of the disturbance could clip the northern portion of SE
TX late tonight so will maintain the slight rain chances. PW
values look meager but there will be some additional forcing with
a 90 kt jet streak. The disturbance will exit the region on Monday
but a weak extension from the disturbance lingers across the
east half of the CWA on Monday. Fcst soundings show a strong
capping inversion in place at 850 mb through 18z eroding between
21-00z. Can`t rule out a few shra/iso tsra along the weakness
trailing the upper level disturbance.

An upper level low will move into New Mexico on Tuesday with weak
upper level ridging amplifying over East Texas. Fcst soundings
show very dry air above 850 mb and a capping inversion in the
850-700 mb layer. The upper low will move east into West Texas
Tuesday night. PW values begin to climb but a stubborn cap should
keep rain chances on the low side. The upper low will move across
the Texas panhandle and into southern KS by Thu 00z. PW values
surge to 1.75 inches over the north and 1.60 inches further south.
Fcst soundings show a semi saturated profile at KCLL and not
quite as saturated toward KIAH. CAPE values increase to between
1500-2000 with LI values near -8. Jet dynamics look impressive
with a well defined splitting jet and SE TX in a 95 kt LFQ. SPC
has outlooked the areas north of I-10 for Wednesday. The system is
fairly progressive and will exit the region Wednesday evening.
Some timing differences between the ECMWF and GFS on Thursday as
the ECMWF looks a bit slower with more energy lagging on the
backside of the upper low. The GFS also drags a cold front through
the area on Thursday while the ECMWF does not. Not sure which is
right so used a model blend for temps Thu/Fri. Could be huge bust
in temps on Friday as the ECMWF is providing a high at KCLL of 92
and the MEX numbers support 78.

Another potent storm system will approach next weekend and
moisture levels start increasing late Saturday with a good chance
of rain next Sunday and Monday. PW values progged to reach 1.90
inches so the area might receive some heavy rain. Still a long
ways off and models have not been the most consistent of late. 43

MARINE...
The onshore winds will gradually strengthen today as the warm front
moves inland. There is a slight possibility for patchy sea fog since
the water temperatures were around 72 from the coast out to the 60
nm buoy (42019) and the surface dewpoint temperatures were in the
lower 70s over the Gulf waters. However, the probability is too low
to mention at this time.

Otherwise, the onshore winds will probably reach advisory criteria
by Tuesday afternoon over the offshore waters between 20 and 60 nm
as a storm system moves into the Southern Plains and Texas. This
will then likely persist through Wednesday and then gradually
diminish as the storm system moves east of the state.

40

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      86  67  86  67  85 /  10  20  10  10  10
Houston (IAH)              85  69  85  69  85 /  10  10  20  10  10
Galveston (GLS)            81  72  81  74  80 /  10  10  10   0   0

&&

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

$$

Discussion...43
Aviation/Marine...40



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