Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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

982
FXUS64 KHGX 181207
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
607 AM CST Sat Nov 18 2017

.AVIATION...
MVFR ceilings have developed at CLL, UTS, CXO, and IAH this
morning. Temporary impacts from MVFR will be also possible at HOU
and SGR before this stratus deck lifts to VFR by mid-morning. The
arrival of a strong cold front will result in breezy to windy
conditions both ahead of and behind this front. Southerly winds
ahead of the front are expected to veer to the west this morning
and increase into the 10-15 knot range with stronger gusts
approaching 25 knots. Isolated SHRA will be possible along the
front (namely near SGR/HOU/LBX/GLS where convergence along the
front will be greater), but have left mention out of TAF due to
anticipated low coverage. Expect the front to reach CLL by 18Z,
the Houston terminals by 21Z, and GLS by 00Z. Strong northerly
winds will persist behind the front tonight at the inland
terminals before decreasing below 10 knots by sunrise as surface
high pressure builds into the region. Winds will be higher at GLS
and persist longer, with 20-25 knot sustained winds gusting to
near 30 knots overnight.

Huffman

&&

.PREV DISCUSSION... /ISSUED 355 AM CST Sat Nov 18 2017/

DISCUSSION...

A warm humid night across southeast Texas, and breezy as well across
northern areas with a tight surface pressure gradient in place due to
a deep surface low located well off to our NE coupled with a surface
high which is centered in the central Gulf. A solid stratus deck has
formed across northwest areas with mostly clear skies closer to the coast.
Near record max temps are expected again today across central and southern
areas with west/southwest surface winds ahead of a cold front that will
move southeast across the area this afternoon.

Model guidance is in good agreement bringing the strong cold front near
CLL around 18Z, and then into the Houston area 20-21Z, and off the coast
23-00Z. A strong capping inversion is in place over the area. However, I
think there is enough low-level moisture and lift along the boundary for
isolated to scattered showers to develop around mid-afternoon as the front
moves through Houston and to the coast. Winds this evening will really
increase along the coast behind the front, and have decided to issue a wind
advisory for the coastal counties for sustained winds of 20 to 30 mph and
gusts 35 to 40 mph tonight, primarily along the immediate coast and bay
shorelines.

Temps will really warm again on Tuesday ahead of another cold front that
is expected on Wednesday. Will see rain chances return ahead of this front
early next week with dry and cool weather on tap for Thanksgiving behind
this front.

Wood

MARINE...
Moderate to strong onshore flow will persist across the offshore
coastal waters this morning, before weakening during the midday and
afternoon hours as a strong cold front approaches. Strong offshore
flow will become established behind the front as it pushes off the
coast tonight with a thin band of showers possible along the front
as it sweeps across the waters. Frequent gusts near gale force are
expected tonight given the thermal gradient behind the front and
anticipated mixing of stronger gusts above the surface (near surface
winds of 35-40 knots) in response to the warm coastal waters. Waves
will also build accordingly with 4 to 6 feet seas nearshore and 7 to
9 feet seas offshore. Elevated winds and waves are expected to
subside by late Sunday as surface ridging slides across the Gulf
Coast states.

Light northeasterly winds will gradually become onshore by Tuesday
ahead of the next cold front moving into the waters late Tuesday or
Wednesday, with another round of caution or advisory flags possibly
needed in its wake.

Huffman

FIRE...
Elevated fire weather conditions will be possible on Sunday behind a
strong cold front as drier air results in minimum relative
humidities falling below 30 percent. Morning 20 ft winds around 5-10
MPH inland and 10-15 MPH along the coast should decrease through the
the day Sunday, but are expected to overlap with drier conditions
long enough to produce at least a brief window for increased
concerns (especially along the coast where higher winds are
expected). Keetch-Byram Drought Index values along the coast have
increased into the 500-600 range, indicative of dry conditions that
may aid in fire starts in finer fuels like grasses.

Huffman


&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      79  43  64  41  66 /  20   0   0   0   0
Houston (IAH)              86  46  66  43  66 /  20   0   0   0   0
Galveston (GLS)            83  54  64  54  67 /  30  10   0   0  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Wind Advisory from 6 PM this evening to 6 AM CST Sunday for the
     following zones: Brazoria...Chambers...Galveston...
     Jackson...Matagorda.

GM...Small Craft Advisory from 6 PM this evening to 9 AM CST Sunday
     for the following zones: Galveston Bay...Matagorda Bay.

     SMALL CRAFT SHOULD EXERCISE CAUTION until 9 AM CST this morning
     for the following zones: Galveston Bay...Matagorda Bay.

     Small Craft Advisory from 6 PM to 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...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 through this afternoon 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.

     Gale Warning from 9 PM this evening to 9 AM CST Sunday 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.

     Small Craft Advisory until 9 AM CST this morning 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.

     SMALL CRAFT SHOULD EXERCISE CAUTION from 9 AM CST this morning
     through this afternoon 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...33
Aviation/Marine...14



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