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
000
FXUS64 KHGX 220542
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1142 PM CST Tue Nov 21 2017

.AVIATION...
Cold front will be working its way through the area overnight. A mix
of MVFR/IFR ceilings will be improving behind the front as drier air
works its way into the area. Might see some showers, so have included
VCSH overnight. North winds will be increasing and getting gusty under
a tightening pressure gradient with the highest speeds expected at GLS.
Quiet tomorrow evening with decreasing winds and clear skies.  42
&&

.PREV DISCUSSION... /ISSUED 800 PM CST Tue Nov 21 2017/

DISCUSSION...
Model guidance continues to point at possible shower and thunderstorm
development later this evening mainly in and around the Matagorda Bay
area as an impulse and associated cold front work their way southward
across the area. Afternoon forecast package has this covered, and only
made some very minor adjustment to the grids on the evening update.

This will be our area`s last best chance of rain until the expected
approach and passage of another cold front around Tuesday or Wednesday
of next week.  42

PREV DISCUSSION... /ISSUED 316 PM CST Tue Nov 21 2017/

DISCUSSION...
Low level flow has become more southwesterly thru the day and the axis
of deeper moisture continues to shift east of the CWA. That being said,
have left some lowish POPs in the grids ahead of the next cool front
and upper trof that`ll be moving thru overnight. Winds at the surface
will back to the northeast ahead of the front itself, and with the
exception of areas closer to Matagorda Bay, limit llvl convergence
and overall substantial rain chances. Cooler and breezy conditions
will arrive overnight, and the next shift(s) may need to keep an
eye on speeds closest to the coast where some guidance suggests
values nearing wind advisory criteria toward sunrise. Look for cloud
cover to diminish during the morning hours Wed, with sunny conditions
prevailing areawide for most of the afternoon.

The remainder of the forecast also looks dry. Mid/upper ridge centered
near Baja will expand north and east, putting us in a deep northerly
flow aloft. The Gulf should remain mostly cutoff from return flow
(expect for a brief 24 hour period ahead of the next reinforcing
front arriving late Sat). Extended grids were generally left as-is
and agree w/ the previous forecaster that daytime highs in the
early part of the weekend will probably be warmer than the blends
indicate. 47

MARINE...
Winds will pick up overnight tonight with the passage of a cold
front through the bays and gulf waters. Small Craft Advisories will
persist over all marine waters from around midnight through midday
Wednesday and may linger over the offshore waters into the mid
afternoon on Wednesday. Highest wind gusts up to near 40 knots are
possible from 20 to 60 nm offshore late tonight into Tuesday
morning.

Winds will then quickly diminish late Tuesday into Wednesday as a
surface high pressure area builds into the Upper Texas coast.
Onshore winds should return by Friday night and Saturday. Another
cold front is expected to move off of the coast later in the
weekend.

FIRE WEATHER...
A dry airmass will settle over Southeast Texas on Thursday and
Friday following the passage of a cold front late tonight or early
Wednesday. Drier conditions are expected on Wednesday, but the
minimum relative humidity values will only drop into the 35 to 40
percent range generally west of the US-59/I-69 corridor. However,
slightly elevated fire weather conditions will occur on Wednesday as
the winds could be 10 to 15 mph over the central and southwestern
areas. The problem on Wednesday will be the highest winds not
syncing up with the driest period. Elevated fire weather conditions
are possible both Thursday and Friday but mainly due to the minimum
relative humidity values falling into the 25 to around 30 percent
range. Winds should stay light and well under 10 mph for the most
part. Northern areas between Brenham, College Station, Madisonville,
and Crockett could see afternoon wind speeds approach 10 mph.

Onshore winds will help alleviate conditions over most of the
weekend for most of the area. Still, relative humidity values will
probably fall into the 35 to 40 percent range across the northern
and far western counties both days. &&

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      51  61  36  65  44 /  20   0   0   0   0
Houston (IAH)              56  65  40  65  43 /  20   0   0   0   0
Galveston (GLS)            60  67  49  64  52 /  20   0   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...Small Craft Advisory until noon CST Wednesday 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 3 PM CST Wednesday 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.

&&

$$

42/31



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