761
FXUS64 KHGX 200809
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
309 AM CDT Thu Jun 20 2024

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(Today through Friday Night)
Issued at 208 AM CDT Thu Jun 20 2024

As I begin typing this AFD, the center of Tropical Storm Alberto
is approaching the coast of Mexico, south of Tampico. But as most
of you already know, Alberto`s winds, rains, and enhanced tides
extend well to the north of the center. Live cameras and water
level gauges show that saltwater inundation is already occurring
along the coast. Coastal flooding impacts during high tide today
will likely be similar to yesterday. Many low-lying coastal roads
will become unpassable again. Ferry services may experience
additional disruptions. As Alberto pushes inland over Mexico, the
steep gradient over the Gulf responsible for the large fetch of
easterly winds should begin to slowly relax. This will result in a
gradual decline in the winds and a decreasing risk of coastal
flooding. That being said, water levels will remain above average
through the weekend and we cannot rule out minor coastal flooding
during high tide on Friday. Current model guidance suggests water
levels will remain just below Coastal Flood Advisory criteria on
Friday. But it`s worth watching.

MIMIC-TPW imagery suggest that much of the deep tropical moisture
is being funneled into south Texas and Mexico, with a somewhat
drier airmass pushing into our neck of the woods. Meanwhile, a
ridge of high pressure over NE CONUS is building southwest towards
Texas. Guidance is in pretty good agreement that the ridge will
continue building this way, increasing our mid/upper pressure
heights. This makes me wonder if global models are a little too
aggressive with diurnal PoPs today. There will be widely scattered
showers and isolated thunderstorms moving in from the Gulf of the
Mexico. Will mesoscale and diurnal forcings allow for numerous
showers or thunderstorms? Or will the aforementioned synoptic
features suppress lift, keeping any shower/thunderstorm activity
isolated to widely scattered. We opted for moderate PoPs (~50-60%)
from I-10 to the coast. PoPs drop off north of I-10, ranging from
~20% in the Brazos Valley to Montgomery Co, to less than 10% in
our northernmost Piney Woods counties. Friday appears to be a
similar day but with a little more ML dry air. Therefore, we
opted for slightly lower PoPs.

Temperature wise, today is expected to be warm and humid with
highs averaging around 90F across the CWA (a little `cooler` at
the coast, and a tad hotter in the Piney Woods). Tonight is
looking seasonably warm and muggy with lows generally in the 70s,
with coastal areas struggling to drop below 80F. With a tinge of
drier ML air leading to less expected cloud coverage on Friday,
highs are forecast to be a little hotter, with low/mid 90s north
of I-10 and upper 80s to low 90s south of I-10 to the coast.

Self

&&

.LONG TERM...
(Saturday through Wednesday)
Issued at 208 AM CDT Thu Jun 20 2024

Model guidance continues to indicate the development of another
tropical disturbance over or near the Bay of Campeche during the
weekend which slowly tracks west northwest towards the eastern coast
of Mexico. In response to the mid to upper level ridge over the
Southern Plains, the disturbance may not be able to move northward
much and could make landfall over the eastern coast of Mexico,
similar to TS Alberto. One difference noted since the model runs
from 24 hours ago, is that the wind field does seem a little more
organized in the latest run...although still somewhat elongated as
it reaches the coastline. The general behavior of this disturbance
is similar to TS Alberto but smaller. Thus, indirect impacts from
the disturbance is possible this weekend into early next week but
not as strong as what we have been experiencing with TS Alberto. The
NHC outlook currently has a 10% chance of formation within the next
48 hours and a 50% chance of formation within the next 7 days for
this disturbance. Interests along the Texas coasts should continue
to monitor the development of this system.

What are we then to expect for the next few days? To start,
conditions are anticipated to be more on the tranquil side on
Saturday for most inland areas. Locations near and along the coasts
could see some isolated/passing showers during the day. On Sunday,
we may begin to see rain chances increasing from southwest to
northeast as low level moisture increases and diurnally driven
showers develop and/or showers and storms associated to the
disturbance move across Southeast TX. A similar weather pattern is
possible on Monday as the disturbance moves inland across the
eastern coast of Mexico. Although we are not expecting significant
impacts with this system inland, we could see limited impacts over
the coastal locations and Gulf waters. This may include higher seas,
gusty winds, strong rip currents, and minor coastal flooding (in
particular during high tide). We will need to wait and see how this
system develops to know more on these impacts, therefore, continue
to monitor the updated forecasts.

On Tuesday and Wednesday, pulses of low level moisture will continue
to move over our region and if the environment remains unstable and
is able to overcome the ridge, we could have isolated to scattered
showers and storms developing each day. This may give some relief
from the heat for some, but with temperatures rising into the mid
90s at some locations (mainly north of I-10) and dewpoints staying
in the upper 70s, we may be looking at daytime heat indices between
105-110 deg F increasing the potential for dangerous heat impacts
for some folks. Make sure to practice heat safety and make the
appropriate adjustments if you plan to work or spend time outdoors.

Cotto (24)

&&

.AVIATION...
(06Z TAF Issuance)
Issued at 1211 AM CDT Thu Jun 20 2024

As expected, we have reached a lull in the shower activity and so
far, only light isolated showers are currently moving over the
southern and coastal portions of SE TX. This trend is expected to
continue for the rest of the night into early morning hours. E
winds have relax a bit inland but GLS/LBX will likely continue to
see gusts between 20-35 kts. Winds are expected to pick up again
around sunrise, mainly for sites IAH southward. Hi-Res models
continue to indicate a few more rounds of showers and iso storms
starting along the coastal areas during the mid to late morning
timeframe, expanding northward across much of SE TX in the
afternoon to evening hours. Will likely continue the issuance of
AMDs and TEMPOs as the event unfolds moving into the local throughout
the day.

Mostly MVFR to VFR conditions are expected, however, stronger
showers could result in brief moments of IFR vis/cigs as well as
stronger wind gusts. Small quick vortices and areas of llvl wind
shear are also not out of the question.

24

&&

.MARINE...
Issued at 208 AM CDT Thu Jun 20 2024

Hazardous winds and seas along with elevated tides continue to
plague our coastal and offshore waters this morning. Coastal
flooding impacts during high today are likely to be similar to
yesterday. Offshore seas this morning are 10-15 feet while winds
are averaging around 25 knots with gusts up to 35 knots. The
steep gradient fueling the large fetch over the Gulf of Mexico is
expected to gradually relax today, resulting in a gradual decline
in winds and seas. However, it may take until Friday morning or
afternoon for conditions to drop below Small Craft Advisory
levels. This is especially true for the offshore seas, which tend
decrease slowly in these large fetch scenarios. Moderate east to
southeast winds and 3 to 5 foot seas are expected this weekend
into early next week.

The National Hurricane Center is monitoring the Bay of Campeche
for another possible tropical system that could materialize by
early next week. Mariners are advised to keep up with the latest
forecast and tropical updates.

For the latest tropical weather updates check out nhc.noaa.gov

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  92  73  93  73 /  20  10  10   0
Houston (IAH)  91  74  91  74 /  40  20  30   0
Galveston (GLS)  88  81  88  81 /  50  30  40  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Tropical Storm Warning for TXZ335>337-436-437.

     Coastal Flood Warning until 7 PM CDT this evening for TXZ214-313-
     335>338-436>439.

     Wind Advisory until 7 AM CDT this morning for TXZ214-238-313-338-
     438-439.

     High Rip Current Risk through this evening for TXZ436>439.

GM...Tropical Storm Warning for GMZ330-350-355-370-375.

     Small Craft Advisory until 7 AM CDT this morning for GMZ335.

&&

$$

SHORT TERM...Self
LONG TERM....Cotto (24)
AVIATION...Cotto
MARINE...Self