Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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781
FXUS64 KHGX 051735
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1235 PM CDT Sat Jul 5 2025

...New DISCUSSION, AVIATION, MARINE...

.KEY MESSAGES...
Issued at 1211 AM CDT Sat Jul 5 2025

- Scattered showers with a few thunderstorms are expected on
Saturday with the best chances west of I-45.

- The next best chance for rain and storms returns Monday and
Tuesday with the arrival of a disturbance from the east.

- Temperatures will trend upward towards the second half of the
  week, with highs generally in the upper 90s.

&&

.DISCUSSION...
Issued at 1136 AM CDT Sat Jul 5 2025

The quasi-stationary mid-level disturbance that has brought very
heavy rainfall to portions of Central Texas continues to have an
effect on our local atmosphere today. Scattered showers and
isolated thunderstorms have already developed across our western
counties, producing locally heavy downpours in the Brazos Valley.
Shower and thunderstorm coverage is expected to expand eastward as
daytime heating provides added instability. Not everyone will
receive rain. But some communities are likely to experience heavy
downpours along with some thunder and lighting. Best chance of
showers and thunderstorms will be west of I-45. But isolated
activity to the east of I-45 is possible as well. These showers
and storms are expected to decrease in coverage as we lose daytime
heating this evening. The aforementioned system is drifting
slowly southward and is expected to be far enough away from the
area to not enhance atmospheric lift by Sunday. In addition, lower
PWATs are expected to filter into the area from the east.
Therefore, the chance / coverage of showers and thunderstorms is
expected to be lower. That being said, day time heating coupled
with the sea breeze and sufficient moisture could still spark off
isolated showers and thunderstorms.


Our attention will turn east as we finally get rid of the current
system over Central Texas. Middle and upper level water vapor
imagery coupled with the current 500MB RAP analysis show a clear
mid/upper trough over the eastern Gulf. This trough will drift
westward over the next couple of days, influencing the SE Texas
atmosphere by Monday and Tuesday. The added lift on top of the
typically high July PWATs would tend to enhance the convective
initiation potential from the sea breeze / bay breeze as well as
other mesoscale processes that interact with the heating of the
day. Model guidance isn`t very consistent regarding rainfall
coverage. But a mid/upper low moving into Texas from the Gulf is
usually, at a minimum, an enhancer of the summertime diurnal
convective cycle. The best chance of showers and thunderstorms on
Monday and Tuesday is across our southern and eastern counties.

Beyond Tuesday, computer models continue to insist on a hotter and
less rainy pattern. Increasingly robust and suppressive ridging is
pretty normal as we head deeper into July. Our forecast for
Wednesday-Friday features hotter temperatures and lower PoPs. But
we are keeping a daily risk of showers and thunderstorms through
the end of the week. This is in part due to the fact that long
term guidance has had a recent dry bias. In addition, there are
already some signals in the guidance showing how the forecast
could become wetter later in the wake. Despite the general
increase in ridging, global models are hinting at a potential
weakness in the ridge sneaking its way southwest from the Midwest
to the Arklatex region on Thursday and Friday. Current
Thursday/Friday PoPs are low. But those PoPs will have to increase
if the trough can extend a little farther south and west. And
even if it doesn`t, enhanced convection to our north and east can
sometimes have a mesoscale ripple effect that can turn a dry
forecast into a wet one.

Temperature wise, we expect highs to average in the low/mid 90s
through Wednesday, then mid/upper 90s by Thursday and Friday. But
those hotter temperatures will be dependent on whether or not
ridging continues to build or not. The humidity will remain quite
fierce. So peak daily heat index values are likely to remain in
the triple digits. Drink your water y`all!

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 1136 AM CDT Sat Jul 5 2025

Scattered shra and isolated tsra likely to continues west of I-45
this afternoon. Confidence is lower regarding shra coverage
for areas near and to the east of I-45. Therefore, we cannot rule
out shra/tsra as far east as IAH. But the best chance of shra/tsra
will be over the Brazos Valley region (CLL). Any shra/tsra should
diminish this evening. Localized areas of MVFR conditions possible
late overnight into the morning hours.

&&

.MARINE...
Issued at 1136 AM CDT Sat Jul 5 2025

Light to moderate onshore flow along with generally low seas
expected through the forecast period. We will also keep a daily
risk of isolated to scattered showers and thunderstorms in the
forecast through the end of the week. Beyond today, the best
chance of showers and storms will be on Monday and Tuesday as a
mid/upper disturbance approaches from the east.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  73  92  72  93 /  10  10   0  10
Houston (IAH)  75  94  75  93 /  10  20  10  40
Galveston (GLS)  81  90  81  90 /  10  10  10  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

DISCUSSION...Self
AVIATION...Self
MARINE...Self