357
FXUS64 KHGX 171030 CCA
AFDHGX
Area Forecast Discussion
National Weather Service Houston/Galveston TX
530 AM CDT Wed Jun 17 2026
...New AVIATION...
.KEY MESSAGES...
- Tropical Storm Watches remain in effect along portions of the
Upper Texas Coast with Tropical Storm Warnings in effect for
portions of the Gulf waters.
- Heavy rainfall amounts of 2-4" with localized higher totals may
lead to additional flash flooding through early this evening across
southern and coastal portions of the forecast area.
- Coastal flooding remains possible through Wednesday evening, with
greatest potential around times of high tide overnight tonight
through early Wednesday morning.
- Hazardous heat will build across southeast Texas late this week
into early next week. Those planning outdoor activities should
prepare for dangerous heat indices.
&&
.DISCUSSION...
Issued at 127 AM CDT Wed Jun 17 2026
Satellite imagery shows the center associated with Potential
Tropical Cyclone 1 emerging over the northwestern Gulf early this
morning. Most convective bands remain displaced to the east and
northeast of the center given the effects of shear over the tropical
disturbance. This system is forecast to lift northeastward along the
Texas coast and adjacent northwestern Gulf through Wednesday
afternoon before eventually tracking toward the vicinity of the
Texas/Louisiana border by Wednesday evening. Heavy rainfall and a
potential for flash flooding will remain the primary impact of
concern over portions of southeast Texas, especially near and along
the coast where additional widespread rainfall amounts of 2-4 inches
with localized totals in excess of 5+ inches will remain possible.
More information on the hydrologic situation is included in an
additional section below. Coastal flooding will also impact the
immediate coast through Wednesday evening as onshore flow
strengthens ahead of the approaching system. A Coastal Flood Warning
remains in effect for Bolivar Peninsula, with a Coastal Flood
Advisory from Galveston Island to the Brazoria and Matagorda
Islands. The best potential for coastal flooding will be from late
tonight into Wednesday morning/early Wednesday afternoon around
times of high tide. No changes were made to Tropical Watches/
Warnings as of the 10 PM NHC Advisory. Tropical Storm Warnings
remain in effect from the Coastal Waters from High Island to
Freeport TX out 20 NM and waters from Freeport to Matagorda Ship
Channel 20-60 nm out and from High Island to Freeport TX 20-60 nm
out where confidence of winds up to 35 kt with gusts potentially
over 40 kt was highest. A Tropical Storm Watch remains in effect for
Galveston Bay as well as Galveston Island, Coastal Galveston County,
Bolivar Peninsula, Chambers, Coastal Brazoria, and the Brazoria
Islands where tropical storm force conditions may be briefly
possible through late Wednesday. A very low tornado threat remains
highlighted along the immediate coast through Wednesday with a
Marginal Risk from SPC. Rain chances will quickly end from west to
east this evening/tonight as the system lifts northeast away from
our region.
Focus will then shift toward building heat through the latter part
of the week and into the weekend and early next week as temperatures
warm back into the lower to mid 90s F (32-36 degrees C) with very
high humidity contributing to heat index (feels like) temperatures
reaching into the 105-112 degrees F (41 to 44 degrees C) range
Thursday through early next week. While we are not expecting to
meet Heat Advisory criteria today, there could be heat index
readings as high as 100-106 F (38 to 41 degrees C) this afternoon.
Hazardous heat products will likely become needed as early as
Thursday. Those planning outdoor activities should be prepared for
the heat and high humidity. Remember to stay hydrated (water or
beverages with electrolytes), take frequent breaks in the shade or a
cool place, and limit strenuous activities if planning to spend time
outdoors. Isolated to scattered afternoon and evening showers and
thunderstorms will be possible each day Thursday-Saturday but a
building ridge may further limit convective development late this
weekend into early next week.
&&
.AVIATION...
(12Z TAF Issuance)
Issued at 530 AM CDT Wed Jun 17 2026
Moderate to heavy rain is spreading onshore this morning with the
heaviest rain affecting HOU and GLS this morning with IFR
conditions. Elsewhere, showers will spread inland with MVFR to IFR
ceilings this morning. Later today, as the low pressure in the Gulf
moves away from the area, rain and showers will taper off. IFR
ceilings are expected to improve to MVFR to VFR. Winds will stay
gusty along the coast at GLL through the day with decreasing winds
at IAH and HOU this afternoon.
&&
.MARINE...
Issued at 127 AM CDT Wed Jun 17 2026
Numerous to widespread showers and thunderstorms will continue to
develop over the marine area tonight into Wednesday as Potential
Tropical Cyclone 1 approaches. A few waterspouts will remain
possible. Onshore winds increase overnight into Wednesday morning as
the system moves into the marine area, followed by moderate to
strong westerly flow behind the departing system Wednesday afternoon
and evening. Seas build to 6-11 feet tonight into Wednesday ahead of
the approaching tropical system and remain elevated through
Wednesday and remain elevated between 5-8 feet Wednesday night into
Thursday. Seas still look to drop to below 6 feet by Friday.
&&
.HYDROLOGY...
Issued at 127 AM CDT Wed Jun 17 2026
Pockets of 4-6+" of rainfall occurred across portions of Southeast
Texas on Tuesday, most notably over northwestern Harris County into
southern Montgomery County where widespread street flooding was
observed. This rainfall along with rainfall from previous days has
left the grounds fairly saturated. This would allow for a quicker
transition of additional rainfall to runoff. This increases the
potential for street flooding, especially along the coast where the
rainfall threat persists through this afternoon as PTC One skirts
along the Upper Texas coastline. Latest high-resolution model
guidance still reflects a tight rainfall gradient with the highest
totals remaining closer to the coast. As a result, the Flood Watch
has been trimmed down to include mostly counties along and south of
I-10. One exception is Montgomery County...keeping them in the Flood
Watch for now since the very saturated soils leaves the southern
portion of the county vulnerable to additional rounds of flooding if
they were to receive even less than an inch of rainfall this
morning. Additional widespread totals of 2-4" with isolated higher
amounts are anticipated with the highest totals along the coast. The
end time of the Flood Watch has also been trimmed to now end on
Wednesday afternoon as the forecast for Thursday has trended drier
in the wake of PTC One. Be sure to remain weather aware and have
multiple ways to receive alerts.
A few river gauges remain in minor flood stage early this morning:
Menard Creek at Rye (RYET2), San Bernard River at Boling (BOLT2),
and Tres Palacios River at Midfield (MTPT2). The San Bernard River
at Sweeny (OCNT2) is currently cresting just below minor flood
stage. Remember that you can monitor updated river forecasts via the
NWS NWPS webpage (https://water.noaa.gov/).
Batiste
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 89 77 94 80 / 10 0 0 0
Houston (IAH) 88 78 94 81 / 50 10 10 0
Galveston (GLS) 88 84 90 84 / 80 30 20 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Tropical Storm Watch for TXZ214-337-338-437>439.
Flood Watch from this evening through Thursday morning for
TXZ164-177>179-197-198-210>212.
Flood Watch through Thursday morning for TXZ199-200-213-214-226-
227-235>238-300-313-335>338-436>439.
Coastal Flood Advisory until 7 PM CDT this evening for
TXZ436>438.
Coastal Flood Warning until 7 PM CDT this evening for TXZ439.
GM...Small Craft Advisory until 9 AM CDT Thursday for GMZ330.
Tropical Storm Watch for GMZ335-350.
Tropical Storm Warning for GMZ355-370-375.
&&
$$
DISCUSSION...CLL
AVIATION...WFO TAE
MARINE...CLL
NWS HGX Office Area Forecast Discussion