Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 270448
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1148 PM CDT Wed Apr 26 2017

.AVIATION...
VFR. No significant changes to the 06Z package. Scattered cirrus
coming across from the west will thin out through the pre-dawn
hours ...post-frontal northerlies to weaken and veer east-southeast
through the late Thursday morning hours. Sky clear with Thursday
afternoon onshore winds between 8-12 kts. 31

&&

.PREV DISCUSSION... /ISSUED 906 PM CDT Wed Apr 26 2017/

DISCUSSION...
A couple of severe thunderstorms (hail producers) developed this afternoon
across parts of our northern counties along/ahead of the cold front.
Activity has moved off to the east, and the cold front is moving off
the coast this evening. The rest of the night should be on the quiet
side with decreasing winds inland and increasing winds across the coastal
waters. Look for low temperatures overnight to drop into the upper 40s
to lower 50s well inland (up north) and into the lower to mid 60s along
the coast. 42

PREV DISCUSSION... /ISSUED 654 PM CDT Wed Apr 26 2017/

AVIATION...
The cold front is currently moving across the city at the bottom
of the hour....veering westerly winds northwest at 15g25 knots
in its wake. With the lone exception of UTS`s vicinity storms...
the remainder of the hubs remained stable enough to preclude the
formation of storms from this afternoon`s towering cumulus. Inland
gusty northwest winds will subside through the evening...remain
up along the coast through 3 or 4 AM...under clear skies. Early
morning winds will veer around to east-southeast through late
morning...generally stick at between 110-130 deg (near coast) /
150-180 deg (inland) at around 10 knots Thursday afternoon. 31

PREV DISCUSSION... /ISSUED 358 PM CDT Wed Apr 26 2017/

SHORT TERM...
Severe warned storm this afternoon in Houston County pretty much
defines where the cap is not and where it is to the south. Storm
has formed along an advancing cold front but there is not much
cumulus development farther down the front towards the College
Station area. College Station did reach 91F today just ahead of
the front. South of this severe storm expect the cap inversion
around 850-700mb to hold as the 12Z CRP and LCH soundings show.
Strongest lift is well north of the area associated with an upper
level low over north Texas. Strong vorticity max was seen in water
vapor imagery with drying between Waco and Abilene on the 6.2
micron GOES 16 water vapor channel. Main severe threat should be
north of the area later this evening with Houston County being the
lone exception right now.

LONG TERM...
Cold front should push through tonight allowing for a cool start
to the day tomorrow after most of the area reaching the upper 80s
today and even low 90s like College Station. It looks like return
flow sets up rather rapidly Thursday into Friday and could
possibly see 90s return again on Friday.

Saturday through Sunday will be a time to monitor as another upper
level trough develops within a rather active jet stream pattern
for the next 7 days. GFS/ECMWF/CMC are all in pretty good
agreement with the center of the upper low over the Four Corners
region by 12Z Saturday. Upper low then moves into the southern
Plains by 12Z Sunday with a cold front pushing into the area.
Overall atmosphere remains rather capped with the elevated mixed
layer Friday and Saturday. Capping may erode enough overnight with
the cold front pushing through the area. There may be a
hail/damaging wind threat overnight into Sunday morning. Shear may
be strong enough to organize storms but linear forcing will likely
keep storms in a line and diminish the potential for discrete
cells. Precipitable water values do get up into the 1.8 to 2 inch
range so a few storms could produce heavy rainfall. The LLJ will
be strong in the 30-40 knot range but not necessarily oriented
normal to the front. There will still be good strong moist inflow
for efficient rain rates in storms but storm motions will be high
so do not think there will be a flood threat at this time.
Overall think a half inch to 1.5 inches of rain will be possible.

Cold front pushes through during the day Sunday with high pressure
building over the area Monday into Tuesday. Long range models
continue the parade of troughs through the plains with another
upper level system developing next Wednesday into Thursday. It
looks like another chance of thunderstorms with a front coming
through Wednesday night next week. 39

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      51  83  67  90  74 /   0   0  10  10  20
Houston (IAH)              56  83  68  88  76 /   0   0  10  10  20
Galveston (GLS)            63  77  74  82  77 /   0   0  10  10  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...Small Craft Advisory until 4 AM CDT Thursday 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.

     SMALL CRAFT SHOULD EXERCISE CAUTION from 4 AM to 7 AM CDT
     Thursday 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 SHOULD EXERCISE CAUTION from 4 AM to 10 AM CDT
     Thursday 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...42
Aviation/Marine...31



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