Flash Flood Warning 23, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1154 PM CDT Mon Sep 10 2018

.AVIATION...
Not much change to the previous package. Storms developing along
the coast from LBX southwestward as expected. Expecting storms to
fill in along the coast and over the Gulf then spread inland on
the slightly enhanced low level flow. PW of 2.2-2.4" will stream
inland this morning and expect scattered to numerous showers and
thunderstorms across the coastal areas expanding inland during the
morning hours into the afternoon hours. Eventually some drier air
should nudge storms east and southeast back out into the Gulf
probably this afternoon. Across the north still expect periods of
MVFR/IFR beneath the frontal inversion these may briefly reach
down into CXO/IAH area after 08z.
45

&&

.PREV DISCUSSION... /ISSUED 1005 PM CDT Mon Sep 10 2018/

DISCUSSION...
A bit quieter for most of the CWA this evening, but we are start-
ing to see some re-development over the SW portions of the region
at this time. The strongest convection looks to be offshore (near
Matagorda Bay)...with a smaller area of activity over Jackson and
Wharton counties. Near-term models seem to keep most of the rains
just offshore overnight before pushing the entire lot inland over
the FF Watch area tomorrow morning/early afternoon. Current grids
appear to have things in hand so no major changes planned at this
time. 41

PREV DISCUSSION... /ISSUED 807 PM CDT Mon Sep 10 2018/

AVIATION...
Moist low levels with low level NE flow across the region. Nose
of the 850 jet racing northeast into the coastal areas and
providing lift over the 3000-4000ft of cooler air. Periods of low
ceilings (IFR) will probably come and go tonight. As the 850 jet
weakens expect the patchy light rain over the area to wane. A
short wave over SAT area should lift east-northeast tonight/early
Tuesday bringing increasing lift to the area. The frontal boundary
stalled over the nearshore waters could be more active after
midnight with storms focusing there and spreading into the coastal
TAF sites. By late morning the boundary should waffle northward
and with the 2.2-2.3" PW nosing in above the boundary expect
elevated storms to develop closer to the 925/850mb frontal
surface. S/W and upper jet weak entrance region should aid lift
over the area. This should lead to more widespread showers and
thunderstorms into the SGR/HOU/IAH/CXO terminals after 14z and
lingering through 21z. Redevelopment could lead to some training
with lengthy periods of MVFR/IFR weather for these terminals. Not
as confident across the north...may end up being more stratiform
rain with VFR ceilings.

Flash Flood watch was extended to 6 pm Tuesday.

45

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      71  83  73  89  73 /  50  60  40  70  30
Houston (IAH)              74  83  75  87  74 /  60  80  60  80  40
Galveston (GLS)            77  82  80  85  79 /  90  90  80  80  50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch through Tuesday afternoon for the following
     zones: Brazoria Islands...Chambers...Coastal Brazoria...
     Coastal Galveston...Coastal Harris...Coastal Jackson...
     Coastal Matagorda...Fort Bend...Galveston Island and
     Bolivar Peninsula...Inland Brazoria...Inland Galveston...
     Inland Harris...Inland Jackson...Inland Matagorda...
     Matagorda Islands...Northern Liberty...Southern Liberty...
     Wharton.

GM...NONE.
&&

Discussion...41
Aviation/Marine...45

Hazardous Weather Outlook
National Weather Service Houston/Galveston TX
720 AM CDT Mon Sep 10 2018

TXZ163-164-176>179-195>200-210>214-226-227-235>238-300-313-
335>338-436>438-111230-
Austin-Brazoria Islands-Brazos-Burleson-Chambers-Coastal Brazoria-
Coastal Galveston-Coastal Harris-Coastal Jackson-
Coastal Matagorda-Colorado-Fort Bend-
Galveston Island and Bolivar Peninsula-Grimes-Houston-
Inland Brazoria-Inland Galveston-Inland Harris-Inland Jackson-
Inland Matagorda-Madison-Matagorda Islands-Montgomery-
Northern Liberty-Polk-San Jacinto-Southern Liberty-Trinity-Walker-
Waller-Washington-Wharton-
720 AM CDT Mon Sep 10 2018

This hazardous weather outlook is for portions of Southeast Texas..

.DAY ONE...Today and Tonight

A flash flood watch is in effect for today and tonight.
Thunderstorms will be possible today which could cause locally
heavy rainfall. The main threat for locally heavy rainfall will be
mainly along the coast but could extend inland towards Houston.
Rain rates in storms of 2 inches an hour may cause street flooding
and rapid rises in bayous.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Thunderstorms will be possible each day the rest of the week
which could cause locally heavy rainfall. Rain rates in storms of
2 inches an hour may cause street flooding and rapid rises in
bayous.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

GMZ330-335-350-355-370-375-111230-
Coastal waters from Freeport to Matagorda Ship Channel TX out
20 NM-Coastal waters from High Island to Freeport TX out 20 NM-
Galveston Bay-Matagorda Bay-
Waters from Freeport to Matagorda Ship Channel TX from 20 to
60 NM-Waters from High Island to Freeport TX from 20 to 60 NM-
720 AM CDT Mon Sep 10 2018

This hazardous weather outlook is for portions of Southeast Texas..

.DAY ONE...Today and Tonight

Showers and thunderstorms are possible. Wind and seas could be
higher in and near stronger storms, and visibilities could be
reduced.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Periods of showers and thunderstorms can be expected. Wind and seas
could be higher in and near stronger storms, and visibilities could
be reduced.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.