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National Weather Service Forecast Discussion

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343
FXUS64 KHGX 210001
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
701 PM CDT Sat Jun 20 2026

...New AVIATION...

.KEY MESSAGES...

- Periods of scattered to numerous showers and thunderstorms will
  persist through Sunday morning, with the potential for locally
  heavy rainfall today. There is a level 2 out of 4 risk for
  excessive rainfall through the daytime hours today, mainly north
  of I-10.

- Heat will remain a concern through midweek, with heat indices
  nearing 107 and overnight lows only falling into the upper 70s
  to lower 80s.

- A high risk of strong rip currents will continue over the
  weekend.

&&

.DISCUSSION...
Issued at 250 PM CDT Sat Jun 20 2026

Ongoing showers and thunderstorms will persist across our southern
zones into the late afternoon, as lingering outflows traverse the
area. We should begin to see a downward trend in convection, as
the area becomes worked over and we lose our daytime heating. That
said, outflows moving through the southern-most portions of the
area will provide a focus for convection through early evening.
There is enough instability in place that if we get intense
updrafts, a few may spin, but this is a low chance and any
spinnies would be very short lived. Otherwise, with the heavy
precip potential, our main concern remains the potential for flash
flooding and a few brief wind gusts are possible.

Another round of showers and thunderstorms are possible early on
Sunday, as a weak low over southern Texas meanders along the
coast. Meanwhile, at the surface, a boundary will remain stalled
in the vicinity of the area and will provide a focus for
convection Sunday morning. Guidance is in relatively fair
agreement on the timing, with the most likely period of activity
between 7 am and 12 pm. PWs will remain on the high side and that
will keep an isolated flooding threat for any shower/storm that`s
able to strengthen. The activity will move out of the area during
the latter part of the morning, as the weak boundary weakens.
Based on the potential for morning convection, will hold off on
issuing a Heat Advisory for tomorrow. It should be noted that if
there is a window of clearing skies/no rain, heat indices will
likely reach 107 again. Am not confident enough on the forecast to
issue any products at this time.

As we head into the new work week, high pressure will build into
the region. This will bring a dry pattern for much of next week.
Day time highs will climb into the lower 90s and overnight lows
will fall into the upper 80s to lower 90s. Moisture will be a
touch lower next week, so heat indices will remain below 107
degrees. However, with multiple days of warm overnight lows, heat
concerns will return across the area.

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 645 PM CDT Sat Jun 20 2026

Shower and thunderstorm activity has gradually diminished over
southeast TX early this evening. VFR is forecast to remain
prevalent over the region through the evening hours. MVFR ceilings
are expected to develop again overnight into Sunday morning.
Another round of scattered SHRA and possibly a few TSRA should
also develop primarily after 08-10Z and persist into the morning.
We maintained a PROB30 mention for most terminals overnight into
Sunday morning.

&&

.MARINE...
Issued at 250 PM CDT Sat Jun 20 2026

Isolated to scattered showers and thunderstorms will be possible
through Sunday morning. Otherwise, light to moderate onshore flow
will persist through this weekend into early next week with seas
between 3 to 6ft.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  76  91  78  93 /  20  20   0   0
Houston (IAH)  78  91  80  93 /  30  20   0   0
Galveston (GLS)  83  89  84  89 /  50  30   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Sunday evening for TXZ436>439.

GM...None.
&&

$$

DISCUSSION...JTC
AVIATION...CLL
MARINE...JTC

NWS HGX Office Area Forecast Discussion