845
FXUS64 KHGX 162108
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
408 PM CDT Sun Jun 16 2024

...New HYDROLOGY...

.SHORT TERM...
(This evening through Monday Night)
Issued at 257 PM CDT Sun Jun 16 2024

As we head into the beginning of the upcoming week, we will enter
into a period of active weather that will be characterized by
widespread, occasionally heavy rainfall which could lead to
flooding along area rivers, streams and bayous as well as some
street flooding. Global models continue to show cyclogenesis in
the Bay of Campeche overnight tonight, likely leading to the
development of a weak closed low by the early hours of Monday.
This feature, as well as a developing lee cyclone to our
northwest, will produce a tighter synoptic pressure gradient and
thus a stronger onshore flow regime that will bring a plume of
deeper tropical moisture to the area. With an associated midlevel
trough providing some vorticity advection along with the impacts
of diurnal heating, we will begin to see shower/thunderstorm
activity pick up across the area overnight into the early hours of
tomorrow and expand in coverage during the afternoon.

Any stronger storms that develop will have the potential to tap
into relatively deep moisture (PWs > 2.0 in by Mon afternoon) and
produce some locally heavy downpours. As such, the WPC has
maintained a Slight Risk of Excessive rainfall roughly along and
south of the Hwy 59 corridor. Urban and poor drainage areas may
see some localized street flooding depending on the location of
any stronger developing storms. Otherwise, rainfall totals will
generally sit around an inch south of the 59 corridor and less
across the northern zones.

Temperature wise, increasing cloud cover along with the impacts of
afternoon rainfall may keep highs from exceeding 90 for much of
the area, especially closer to the coast. Despite this, dew points
in the mid 70s will still contribute to heat stress as heat
indicies once again reach the century mark. Overnight lows,
bolstered by WAA and greater cloud cover, will sit in the mid to
upper 70s inland and near 80 along the coast.

Cady

&&

.LONG TERM...
(Tuesday through next Saturday)
Issued at 257 PM CDT Sun Jun 16 2024

A closed low is expected to develop in the Southwestern Gulf by
Tuesday. Combined with high pressure/ridging spanning the eastern
sea board, this will greatly tighten the pressure gradient, setting
up a 30-40 knot LLJ over portions of the Texas/Louisiana coast.
Converging winds along the coastline & forcing from this system, in
combination with deep moisture (PWs in excess of 2" at times), will
result in numerous storms across the Northwestern Gulf throughout
the first half of the week. Forecast soundings during this period
feature deep saturation, with a warm cloud layer in excess of 15,000
ft, still indicative of high precipitation efficiency necessary to
produce heavy rainfall.

WPC has a Moderate (level 3/4) to Slight (level 2/4) Risk of
excessive rainfall over SE Texas for Tuesday through Wednesday.
These storms will be capable of producing heavy rainfall, with areas
south of US-59 most at risk for heavy rains and flooding (denoted by
the Moderate Risk area). This includes the Houston Metro area, with
urban locations such as these already prone to flooding due to poor
drainage. Areas south of US-59 could see rainfall totals of 5-8
inches with isolated higher amounts possible. Areas to the north
will generally receive 2-4 inches during this same period. This
rainfall will likely result in rises in rivers, streams and creeks.
Additionally, strong winds and long fetch induced by this system may
result in moderate coastal flooding as well. Some uncertainties
still remain in the forecast, mainly with the track of the system.
It`s important to remember that even small deviations in the
expected path of this system can greatly shift where the heaviest
rain falls. Regardless, confidence in tropical development is
growing, and NHC now has a 70% chance of this system becoming a
tropical cyclone within the next 7 days. Impacts from this low will
still be felt across SE Texas, regardless of if it becomes a named
cyclone.

The heavy rainfall threat diminishes on Thursday as the
aforementioned system tracks into Mexico and dissipates. However,
wet conditions look to continue through the end of the week as a
broad upper level low traverses through the Gulf of Mexico. An upper
level high over portions of the Southern Plains looks to keep that
next disturbance restricted to the Southern Gulf, thus limiting it`s
impacts to SE Texas.

03

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 1246 PM CDT Sun Jun 16 2024

The current TAF period will begin a period of deteriorating
conditions that will likely last several days. For the remainder
of today and into tonight, VFR conditions are expected to prevail
with winds remaining around 5-10 knots. Shower and thunderstorm
activity will begin to increase after around 09Z tomorrow morning,
with rainfall beginning along the immediate coast and expanding
inland over the course of the day. This will be accompanied by an
increasing SE wind, with wind speeds reaching around 10-15 knots
with gusts occasionally in excess of 20 knots. Any stronger storms
that do develop may produce the occasional stronger wind gust
and/or visibility reduction, but in general cigs are expected to
remain in the MVFR range.

Cady

&&

.MARINE...
Issued at 257 PM CDT Sun Jun 16 2024

Winds and seas will increase over the next several days as the
pressure gradient tights from a developing low over the Southwestern
Gulf of Mexico. Ample Gulf moisture will bring numerous
showers/storms daily, beginning later tonight into the upcoming
week. Small Craft Advisories take effect on Monday and will likely
be extended over the next several days as winds approach 20 to 30
knots with gusts in excess of Gale-Force possible. Seas are expected
to reach 10 to 15 feet at times. These strong onshore winds over a
long fetch will also bring a high risk of rip currents and
potentially moderate coastal flooding across the Texas coastline as
early as Tuesday. Forecasted winds and seas may vary depending on
how this system evolves. Gale warnings cannot be completely ruled
out at this time. Stay tuned over the next several days as we
monitor this system.

Conditions begin to improve on Thursday as the aforementioned
tropical system dissipates over Mexico, with winds and seas falling
below Small Craft Criteria on Friday.

03

&&

.HYDROLOGY...
Issued at 408 PM CDT Sun Jun 16 2024

Ongoing river flooding persists for a few sites along the Trinity
River. The Trinity River near Liberty continues to gradually rise in
moderate flood stage and may crest into major flood stage later this
week. The Trinity River at Riverside crested in moderate flood
stage, but will take a while to recede. The Trinity River at Moss
Bluff continues on a slow and gradual climb in minor flood stage.
The current forecasts do not take into account the upcoming rainfall
event later this week.

We are continuing to monitor an area of disturbed weather currently
over the Yucatan Peninsula that is expected to become a broad
surface low in the Bay of Campeche (southwestern Gulf of Mexico)
over the next few days. This low would then have the potential to
become a tropical depression by midweek as it moves slowly westward
or west-northwestward. REGARDLESS OF TROPICAL DEVELOPMENT, the
deeper tropical moisture from this system will bring periods of
moderate to heavy rainfall for portions of Southeast Texas (mainly
areas near and south of I-10). Tuesday into Wednesday in particular
look to be the main days with heavy rainfall potential. Locally
heavy rainfall may lead to localized instances of street flooding in
some areas. Forecast uncertainty remains rather high though, but for
now we`re continuing with the messaging of 5-8" of rainfall near and
south of US-59/I-69 and 2-4" north of US-59/I-69. That total
rainfall forecast is over a four day period from Monday-Thursday.
New river flooding will be possible as early as Tuesday. We`ll also
be monitoring for the potential for flooding along area creeks and
bayous as well. With there being general consensus for the higher
end of the rainfall amounts occuring near/along the coast, this will
be beneficial rainfall for drought stricken areas (mainly those near
Matagorda Bay).

Remember to heed any instructions from your local officials and to
never travel through ANY flooded areas or roadways. TURN AROUND,
DON`T DROWN. Please monitor updated forecasts via the NWS NWPS
webpage (https://water.noaa.gov/).

Batiste

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  76  91  75  89 /  20  40  10  30
Houston (IAH)  77  89  75  84 /  40  70  30  70
Galveston (GLS)  80  88  80  86 /  70  80  60  80

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Should Exercise Caution through Monday afternoon for
     GMZ330-335-350-355-370-375.

     Small Craft Advisory from 1 PM Monday to 7 AM CDT Tuesday for
     GMZ330-335-350-355-370-375.

&&

$$

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