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735
FXUS64 KHGX 151113
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
613 AM CDT Sat Jun 15 2024

...New AVIATION...

.SYNOPSIS...
-- Changed Discussion --
Issued at 243 AM CDT Sat Jun 15 2024

Heavy rainfall, rough surf, and hazardous seas are a concern this
upcoming week due to a broad area of low pressure that is
expected to slowly organize over the west / southwest Gulf of
Mexico. As of 2AM CDT, the National Hurricane Center is giving
the potential system as 50% chance of development by the middle of
the week. The impacts to southeast Texas are likely to be the
same regardless of whether or not the system develops.

The primary concerns are:

1) Heavy rainfall

 Moisture from the system will bring a daily risk of showers and
 thunderstorms Monday to Thursday. Rainfall may be heavy at times
 and could result in flooding. Rainfall totals through Thursday
 are expected to range from 5-7 inches near the coast, 2-4 inches
 around I-10, and 1-2 inches for areas farther north. Locally
 higher amounts possible.

2) Hazardous seas

 Strong east to southeast winds of 20-30 knots with higher gusts
 over the Gulf waters are likely to result in high seas. By late
 Tuesday into Wednesday, seas offshore may be in the 6-10 foot
 range with occasionally higher waves. Small craft advisory
 conditions are likely through much of the upcoming week. Gale
conditions, at least in gusts, cannot be ruled out.

3) Rough surf / elevated tides

 The rip current and coastal flooding risk is expected to increase
 through mid-week. Hazardous conditions for swimming are likely.
 Minor coastal flooding is possible. Not a good week for beach
 recreation.
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&&

.SHORT TERM...
(Today through Sunday Night)
Issued at 243 AM CDT Sat Jun 15 2024

Oh, hi there! I wasn`t expecting anyone to come by this portion of
the AFD, I just assumed y`all would skip to the long term. But come
in, come in! We`ve got weather to talk about here, too! It`s not as
exciting as an unsettled pattern and possible tropical shenanigans,
but there are some things you`ve got to know.

First off, heat. We`ve got a western US ridge building its way
across the southern tier of the US, which should give us subsidence
aloft, generally supportive of higher daytime temperatures. We
should also see the return of onshore flow, boosting humidity - and
via that, the temperature floor that we`re starting from. 850 temps
do look fairly stable...they may even dip slightly today? On net,
it`s got me continuing to think we`ll see temperatures hanging out
modestly above seasonal averages. And while that doesn`t sound like
much, we just are in a place where the typical summertime heat is
distressingly close to being dangerously hot, so even a modest
increase in heat levels can be a cause for concern. As it
is...forecast heat index values are solidly in the triple digits
across the area both days, but also below the 108 threshold for a
heat advisory for all but the most isolated hot spots.

It`s the weekend, the weather will be nice for much of it, and I
don`t blame anyone who wants to spend most of it outside.
Just...be sure to keep plenty of water around for hydrating while
you`re doing that. And if you`re near a place that`s air-conditioned
for some breaks, that`s good too. The threat level implied by wet
bulb globe temperatures peak out in the high range across Southeast
Texas both days, so exertion in direct sun can still pose threats -
but it can also be circumvented by minimizing that exertion during
the times of most intense sun and heat. The more you can nudge
activities to the morning or evening, the better, as WBGT looks to
peak between noon and 5 pm.

Finally, come Sunday, the long advertised period of unsettled
weather discussed in the long term is stating to sneak into the
short term. Showers and storms are possible as early as Sunday
morning out on the Gulf, and we could see an isolated shower or
storm try to pop up Sunday afternoon generally coastward of I-10
west of Houston and coastward of US-59 east of Houston. Most will
still dry, but don`t be too surprised if one or two spots get some
rain. While the potential for rain pulls back to over the Gulf
Sunday evening as we lose daytime heating, the incoming pattern
shift will begin to make itself known late Sunday night, and rain
chances will begin to increase near the coast late Sunday night
towards Monday morning. The stronger onshore flow and increase in
cloudiness overnight should also keep overnight lows up a few
degrees more, even for large chunks of inland Southeast Texas.

&&

.LONG TERM...
(Monday through Friday)
Issued at 243 AM CDT Sat Jun 15 2024

A broad area of low pressure that is expected to materialize over
the west and southwest Gulf of Mexico will be the dominant feature
in the long term. A steepening LL gradient between the low and a
high pressure system over eastern CONUS will increase east to
southeast LL flow across the Gulf, pushing deep tropical moisture
into SE TX. PWAT values will increase from the 1.50-2.00" range on
Monday to 2.50-3.00" by late Tuesday into Wednesday. As a result,
there is a good chance of daily showers and thunderstorms through
at least Thursday, possibly even Friday. In addition to the
moisture, vort maxes embedded in the mid to low level flow may
enhance lift and LL convergence. Global models suggest that one
such disturbances could impact the region on Tuesday into
Wednesday, further enhancing rain and thunderstorm activity.
Heavy showers and thunderstorms are possible area wide this
upcoming week. However, the southern half of the CWA (especially
the coast) continue to have the best chance of heavy rainfall and
flooding. Our current predicted rainfall totals through Sunday
range from 5-7 inches near the coast, to 2-4 inches around the
I-10 corridor, and 1-2 inches across much of the northern CWA. But
given the higher PWATs, locally heavier totals will be possible
across the region. The steep LL gradient will also enhance east to
southeast winds, especially on Tuesday-Thursday. Wind gusts near
the coast could exceed 30 MPH while inland areas experience 20-25
MPH gusts. Overnight deterministic runs suggest coastal winds
could gust over 40 MPH. We opted to keep our gusts closer to 30
MPH. However, we may need to increase our coastal winds if the
overnight runs turn out to be a trend. Hazardous beach conditions
in the form of dangerous surf and elevated tides are likely
Tuesday-Thursday.

The low pressure system of interest could develop into a tropical
system by the middle of the week. The National Hurricane Center is
giving the system a 50% chance of developing into a tropical
depression. HOWEVER, it is important to note that the impacts to
SE TX will likely be the same regardless of whether or not the low
develops into a tropical system. Heavy rainfall and hazardous
surf/seas will be a concern regardless of development.

Self

&&

.AVIATION...
-- Changed Discussion --
(12Z TAF Issuance)
Issued at 613 AM CDT Sat Jun 15 2024

Patchy fog across SETX, but so far only TAF site brought to MVFR
is known problem spot LBX. However, it`s happening at enough other
sites that I add some modest VSBY reduction at other known trouble
spots CXO and SGR, plus a conservative TEMPO 6SM at IAH.
Conditions should return to unlimited rapidly as sun rises, around
14-15Z. Winds light/VRB early to become ESE 5-10 kts this
afternoon, becoming light/VRB again tonight.

No explicit mentions of precip in any TAF sites just yet...but
there could be a few quick, stray showers from IAH coastward in
the pre-dawn hours tomorrow.In the IAH extended, there is a non-
zero chance for an isolated shower/storm, but most or all activity
should be over the Gulf or right on the coast. May need to
evaluate need for any rain mentions at GLS/LBX by 00Z issuance.
-- End Changed Discussion --

&&

.MARINE...
Issued at 243 AM CDT Sat Jun 15 2024

A broad area of low pressure is expected to materialize in the
west / southwest Gulf of Mexico over the next couple of days. A
resulting gradient will gradually increase winds and seas through
the middle of the upcoming week. Through the rest of the weekend,
winds are expected to be light to moderate with seas of 2 to 3
feet. Winds and seas should begin increasing Sunday into Monday.
Southeast winds of 15 to 20 knots with offshore seas building to 4
to 6 feet are expected by Monday afternoon. By Tuesday night into
Wednesday, sustained winds are projected to increase to around 25
knots with gusts over 30 knots. Offshore seas are expected to
reach 6 to 10 feet, with locally higher waves likely. Showers and
thunderstorms are expected in addition to the winds and seas.
Conditions are expected to be mostly dry today. Sunday has a
better chance of scattered showers and storms. But the best chance
of heavy showers and thunderstorms will be from Monday to
Wednesday. Winds and seas may be higher in and near any
thunderstorms. Small Craft Advisory level conditions are likely
this week. Gale conditions, at least in gusts, cannot be ruled
out.

The National Hurricane Center is giving the low a 50% chance of
development by the middle of the week. It is important to note
that the offshore impacts may be the same regardless of whether
or not the system develops.

&&

.PRELIMINARY POINT TEMPS/POPS...
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College Station (CLL)  94  72  93  74 /   0   0  10  10
Houston (IAH)  94  75  93  76 /   0  10  20  20
Galveston (GLS)  90  82  90  80 /   0  10  30  50
-- End Changed Discussion --

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

SHORT TERM...Luchs
LONG TERM....Self
AVIATION...Luchs
MARINE...Self