505
FXUS64 KHGX 160014
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
714 PM CDT Wed May 15 2024

...New AVIATION...

.SHORT TERM...
(This evening through Thursday Night)
Issued at 312 PM CDT Wed May 15 2024

A modest increase in surface moisture, thanks in large part to the
redevelopment of low level southeasterly winds, has brought
surface dew point temperatures back into the upper 60s across much
of the area this afternoon. Meanwhile, a slight increase in the
strength of the prevailing midlevel ridge over the area has
allowed for highs to break into the lower 90s at many
locations.

The main weather story in the immediate term continues to surround
the potential for periods of heavy rainfall, as well as some
isolated severe storms, during the afternoon and evening hours
tomorrow. As has remained evident in the previous several forecast
packages, conditions will become favorable for periods of heavy
rain. The approach of a weak surface low, and its resultant
tightening of the surface pressure gradient, will continue to
provide a surge in moisture with total PWs expected to surge to
around 2.0 - 2.25 in across most of the area of the afternoon. A
weak surface warm front associated with this surface low will be
subsequently situated just north of the I-10 corridor. Aloft, the
approach of a robust midlevel trough (along with several weak
embedded impulses ahead of it) will provide sufficient lift to
trigger the development of showers and storms beginning in the
afternoon. Environmental parameters also favor the development of
some stronger storms, with SREF mean SBCAPE values in excess of
2000 J/Kg across much of the area by the afternoon and bulk shear
values of around 50 kt.

HiRes models remain in fairly good agreement in showing the
initial convective mode as a few discrete storms as the midlevel
trough swings into the Southern Plains, transitioning to the
development of a fairly robust MCS that will move through the area
during the late afternoon/evening. QPF amounts have remained
fairly steady, with the highest rainfall totals expected to remain
situated north of the I-10 corridor (2-4" widespread, isolated
amounts of around 6"). Given the significant antecedent rainfall
that has impacted this area over the past several weeks, this will
pose a threat for flash flooding (WPC has maintained a Moderate
Risk of Excessive Rainfall as a result). Heavy rains will also
result in potential rises to area rivers/creeks/streams, including
locations that have been experiencing ongoing river flooding in
recent weeks. Furthermore, given the favorable instability and
shear in place, there will be a potential for strong winds and
large hail in any stronger storms that do develop.

Storms should generally taper off just before midnight tomorrow,
though lingering PVA due to the passage of the trough aloft may
result in some additional scattered activity on Friday (see long
term section below).

Cady

&&

.LONG TERM...
(Friday through next Tuesday)
Issued at 312 PM CDT Wed May 15 2024

Friday expecting continued scattered shower and thunderstorm
activity...mainly over coastal counties...along convergence axis
associated with left over boundary. Should finally see any lingering
convection shift east of the area Friday evening...as upper trough
axis shifts east.

Saturday through Wednesday...will see a prolonged period of
onshore flow and hot...humid conditions. At upper
levels...expecting flow pattern to be characterized by upstream
ridge and downstream trough..with general subsidence. At low
levels...moderate onshore flow will continually pump in moisture
from the Gulf. As a result looking at a hot and humid period from
Saturday on with little or no rain. Upper ridge shifts E of the
area by next Tue and Wed...but surface convergence...boundary
forcing remains well to the NW and airmass somewhat capped even
then.

DR

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 647 PM CDT Wed May 15 2024

Light winds, high clouds and VFR conditions can be expected
tonight through early Thursday morning. MVFR CIGS and
isolated showers/storms begin to develop mid Thursday morning into
the early afternoon. A complex of thunderstorms will push across
the region from northwest to southeast during the late
afternoon/evening, bringing periods of IFR VIS/CIGS. These storms
will be capable of producing locally heavy rainfall, hail and
strong wind gusts. There will be a lull in rain chances behind
this main complex during the late evening, though another isolated
round of storms could develop overnight.

03

&&

.MARINE...
Issued at 312 PM CDT Wed May 15 2024
round of
isolated storms looks to be possible beyond
Light onshore flow will strengthen some tonight and may approach
small craft should exercise caution levels. There will be a chance
of showers and thunderstorms from late tomorrow afternoon through
Friday evening although coverage will be more widespread farther
inland. Winds and seas would be locally higher in and near
thunderstorms. For Saturday through middle of next week...expecting
continued light to occasionally moderate onshore flow but with
little or no rain.

DR

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  67  81  69  84 /  10  80  60  20
Houston (IAH)  71  83  73  86 /  10  70  60  30
Galveston (GLS)  76  81  76  82 /  10  50  50  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch from Thursday afternoon through Friday morning for
     TXZ163-164-176>179-195>200-211>213-300-313.

GM...Small Craft Should Exercise Caution through Saturday morning for
     GMZ350-355-370-375.

&&

$$

SHORT TERM...Cady
LONG TERM....Reilly
AVIATION...03
MARINE...Reilly