Special Weather Statement, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
626 PM CDT Tue Jul 20 2021

.AVIATION...
Spotty isolated showers will continue this evening, but overall
impacts should be insignificant. VFR conditions should be the rule
for most of the night, though may see some brief MVFR cigs north
of CXO toward morning. Otherwise continued VFR Wed. Sct popcorn
shra and iso tsra should develop with daytime heating and as the
diffuse boundary near the coast washes out/drift north.  47

&&

.PREV DISCUSSION... /ISSUED 347 PM CDT Tue Jul 20 2021/
SHORT TERM [Through Wednesday]...
The majority of the thunderstorms today have remained offshore
today, but some thunderstorms have developed across the coast this
afternoon. These storms will move offshore in the next few hours
with some lingering showers continuing through the evening. A lull
in the precipitation is expected tonight over land with showers
and thunderstorms persisting over the Gulf. The north to
northeasterly flow that occurred today will become more variable
tomorrow, and then east to southeasterly tomorrow evening as the
upper level low moves into West Texas. Isolated showers and
thunderstorms begin to move onshore during the morning tomorrow,
and then expand inland through the afternoon as a diffuse warm
front/sea breeze moves through. Expecting coverage to expand
between noon and 4pm south of I-10, then north of I-10 between 4pm
and sunset. The diffuse warm front will bring in higher slightly
PWATS with outflow boundary collisions being the main driver in
where and when thunderstorms pop up. Breaks in the cloud cover
tomorrow will lead to slightly warmer temperatures with afternoon
highs climbing into the low 90s.

Fowler

LONG TERM [Wednesday Night Through Tuesday]...
Wednesday night deeper moisture poised over the Gulf will start
flowing back into SETX as the upper low in WestCentralTX drifts
westward and upper level winds become more favorable for lift with
upper diffluence and speed max rotating around the low. PW of
1.8-2.1" ramp up. Expect rain chances in the morning near the
coast to expand inland and scattered showers and thunderstorms to
develop a little earlier in the day and potentially wane a little
sooner in the afternoon as the upper ridging/subsidence increases
over the Gulf and expands into the coastal areas. Currently
leaning toward a slightly slower arrival of the subsidence and
will maintain the higher chances Thursday. Thursday night into
Friday should begin the warmup with a fairly abrupt drop in rain
chances. Temperatures in the afternoon Friday and Saturday should
be in the mid to upper 90s...upper 90s more likely on Saturday.
Staying hot on Sunday as the upper ridge builds in directly
overhead Saturday and then slowly starts to edge away on Sunday.
By late Monday as well as on Tuesday will get into easterly flow
aloft and could help to focus storms along the I-10 corridor as
moisture levels increase again.

Heat safety will become a focus again Friday through Sunday with
abundant sunshine, heat indices 104 to 109. May need heat
advisories this weekend.
45

MARINE...
It was an active day over the Gulf waters today but
coverage has finally plummeted. Winds should be fairly light
tonight and Wednesday as front washes out. Onshore flow develops
Thursday with quick increase in moisture leading to more showers
and thunderstorms. Winds steadily picking up Friday as heights
fall over West TX and upper ridging builds in to the western Gulf
tightening the gradient. Fortunately the gradient will be stronger
over STX/Coastal Bend and primarily our western waters get
clipped with it Friday afternoon/Saturday. Seas should start
building in response to the stronger winds and may get into SCEC
Saturday. 45

TROPICAL...
Dusty for the most part across the Atlantic development region.
Some potential for development day 4-5 with the trailing front off
the East Coast but no impacts for us in SETX.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      72  90  73  92  76 /  40  30  10  40  20
Houston (IAH)              74  90  77  93  79 /  20  50  30  50  10
Galveston (GLS)            79  88  82  92  83 /  40  40  20  40  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.

&&