254
FXUS64 KHGX 190022
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
722 PM CDT Tue Jun 18 2024

...New AVIATION...

.SHORT TERM...
(This evening through Wednesday Night)
Issued at 300 PM CDT Tue Jun 18 2024

The immediate forecast concern continues to surround the approach
of PTC One and its potential to bring periods of heavy rain,
gusty winds, and coastal flooding to SE TX. Latest guidance
continues to show the center of the aforementioned system
maintaining its slow westward motion towards the Eastern Mexico
coast, with recent analysis indicating the potential tropical
storm force wind field extending over 300 nm from the center. As
such, a Tropical Storm Warning has been for portions of the SE TX
coast between Port O`Connor and San Luis Pass in addition to the
warning that was already in effect over the coastal waters. The
primary threats associated with this system, and their associated
timing, are as follows:

* HEAVY RAIN: While models continue to show a trend of the highest
  rainfall amounts concentrating to our southwest, we continue to
  anticipate an expansion of shower/thunderstorm coverage between
  tonight and tomorrow afternoon, with the heaviest of rain still
  expected to fall closer to the immediate coast. With growing
  confidence in the shift of highest rainfall amounts to the
  south, we have cancelled the Flood Watch for locations north of
  the I-10 corridor. The greatest concern is for the areas in and
  around Matagorda Bay, where 4-6" of rain could fall (with
  locally higher amounts). For other locations along and south of
  the I-10 corridor, can now expect 2-4" of rain. Rainfall will
  taper off tomorrow night.

* WIND GUSTS: Sustained winds to tropical storm force will be
  possible tomorrow along the immediate coast between Port
  O`Connor and San Luis Pass, as well as for all offshore zones
  except Galveston Bay. For other coastal locations, winds could
  approach 30 knots with occasional gusts as high as 35 knots.
  Further inland, sustained winds may reach up to 20 knots with
  some higher gusts at times.

* COASTAL FLOODING: Sustained strong onshore winds will produce
  coastal flooding, with the greatest inundation (2-4 ft) in and
  around Galveston Bay. Flood prone roadways like Hwy 87 along
  the Bolivar Peninsula may be impacted in addition to other low
  lying areas. The impacts will be greatest during tomorrow
  morning`s high tide. Elsewhere, 1-3 ft of inundation are
  possible which may also impact low-lying and flood prone areas.

In general, the greatest impacts from this system will be felt
overnight through tomorrow afternoon...with conditions beginning
to improve roughly after sunset on Wednesday as the system pushes
further inland. While PTC One may be designated as a Tropical
Storm before it makes landfall and thus acquire a name, it`s
important to note that this will not change the expected impacts
to our area. This is a time to be weather aware and prepared- have
multiple ways to receive warnings and exercise caution if
traveling. Remember the phrase, "Turn Around, Don`t Drown". Never
attempt to drive through a flooded roadway!

Just to note...overnight lows will remain in the upper 70s to 80
for tonight and tomorrow night, while tomorrow`s highs will sit in
the mid to upper 80s (with lower temperatures west of I-45, where
rainfall coverage will be greater).

Cady

&&

.LONG TERM...
(Thursday through next Monday)
Issued at 300 PM CDT Tue Jun 18 2024

Potential Tropical Cyclone One is expected to track into Mexico and
dissipates during the second half of the work week. Impacts will
begin to decrease as this system distances itself from the SE Texas
coast. There is still a Marginal (level 1/4) Risk of Excessive
Rainfall on Thursday, but overall storms will be more
scattered/isolated in with lighter rainfall totals expected. Rivers,
streams, creeks and bayous may still be elevated at this time as
well. Strong winds will also linger across the Gulf waters, bringing
minor to moderate coastal flooding through Thursday evening.
Additional Coastal Flood Advisories/Warnings may be necessary during
this time period to allow inundation to recede. We`ll have to
carefully watch how conditions evolve to see if these additional
hazards may be warranted.

Conditions will improve further on Friday as a +590 dam mid level
ridge settles in over portions of the Southern CONUS. Deep moisture
will still be available across the Texas Gulf Coast, and with little
capping aloft any passing impulses should be able to fire up
scattered showers and storms into the beginning of next week.
Notably, NAEFS climatological 200mb heights with the upper level
ridge are rather high for this time of year. WPC`s 500mb mean
cluster analysis indicates heights of 594 dam spanning portions of
the Southeast/South-Central CONUS into the weekend. High
temperatures are progged to climb into the upper 80s to upper 90s
during this period. Deep gulf moisture and high dewpoints will
create humid afternoon conditions, resulting in increasing heat
stress.

Global models indicate the development of another area of low
pressure over the Southwestern Gulf of Mexico over the weekend/into
next week. It is hard to give specifics on this unrealized system
given the uncertainty created by the ongoing Potential Tropical
Cyclone One. The lack of a deepening surface low over the Rockies
and the presence of surface high pressure across Texas would suggest
a weaker pressure gradient across the SE Texas coastline. While the
ridge overhead looks to weaken into next week, it`s presence over
the Desert Southwest/Southern Plains may keep this system restricted
to the Southern Gulf. The different atmospheric setup would suggest
that this upcoming system won`t have a broad, anomalous wind swath
like Potential Tropical Cyclone One. In other words, it appears that
impacts to SE Texas with this upcoming system would be more limited.
Still, it is far too early to "lock in" this forecast. Stay tuned
these next several days as we monitor how this next disturbance
evolves.

03

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 651 PM CDT Tue Jun 18 2024

Periods of SH/TS associated to a tropical disturbance located
near the Bay of Campeche will continue throughout much the TAF
period. Further AMDs and TEMPOs will likely be required as the
disturbance slowly tracks N-NW over the Gulf of Mexico.

For tonight, conditions are expected to remain fairly tranquil
for areas IAH northward. However, for locations south of IAH,
periods of -SHRA can be expected to continue, in particular for
areas closer to the coast. Areas of SH/TS will increase during the
day Wed as the system moves closer towards the eastern coast of
Mexico. We are expecting conditions to be mainly MVFR to VFR for
much of the period, but there is a chance vis/cigs could briefly
lower to IFR with stronger showers/storms. E winds will remain
elevated for much of SE TX as well, possibly varying between 10-20
kts with higher gusts over the Brazos and Piney Woods Region and
between 15-25 kts with higher gusts over the central and coastal
regions. Conditions are to improve Wed night as the system makes
its way into E Mexico.

24

&&

.MARINE...
Issued at 300 PM CDT Tue Jun 18 2024

A potential Tropical Cyclone will bring numerous thunderstorms,
strong winds and high seas across the southwestern Gulf of Mexico
through early Thursday. Tropical Storm Warnings and Small Craft
Advisories are in effect, with winds of 25-35 knots and gusts up to
40-50 knots expected through early Thursday. Seas are expected to
reach 15 to 20 feet at times over the Gulf Waters. These strong
onshore winds over a long fetch will also bring a high risk of rip
currents. Tide levels rising to 3.5-5 feet above MLLW will bring
minor to moderate coastal flooding with 3-4 feet on inundation
across the Texas coastline. Conditions will begin to improve on
Thursday as the aforementioned tropical disturbance dissipates over
Mexico, though Small Craft Advisories will likely be needed into
Friday as high winds and seas linger in the system`s wake. Caution
Flags may still be warranted over the weekend.

03

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  75  85  74  92 /  30  60  30  30
Houston (IAH)  76  87  75  91 /  60  70  40  50
Galveston (GLS)  79  87  82  88 /  80  80  70  70

&&

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

     Flood Watch through late Wednesday night for TXZ210-214-226-227-
     235>238-313-335>338-436>439.

     Coastal Flood Warning until 7 AM CDT Thursday for TXZ214-313-
     335>338-436>439.

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

     High Rip Current Risk through late Wednesday night for
     TXZ436>439.

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

     Small Craft Advisory until 7 AM CDT Thursday for GMZ335.

&&

$$

SHORT TERM...Cady
LONG TERM....03
AVIATION...Cotto (24)
MARINE...03