Flash Flood Warning 9, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
339 PM CDT Mon Jun 8 2020

...HEAT ADVISORY IN EFFECT FROM NOON TO 7 PM CDT TUESDAY...

.SHORT TERM [Through late Tuesday]...

Shower and isolated thunderstorm activity flaring up generally
south of the I-10 corridor this afternoon. The heaviest activity
is and will likely continue to be focused across those counties
surrounding Galveston Bay. The impetus to this late day activity
comes from a far southwestern band of TD Cristobal interacting
with the local sea breeze within a unstable moistened and heated
near coastal air mass. Anticipating this behavior to dwindle past
sunset this evening.

The main story tomorrow will be the heat. A Heat Advisory is in
effect tomorrow afternoon as many communities will warm up into
the middle to upper 90s by early afternoon within a continued high
pwat air mass of around 1.75 to 2.00 inches. As what is left of
Cristobal is absorbed within a Central Plains shortwave trough, our
regional column flow in the mid layers will swing southwesterly.
This will create a mid level warm nose and place a lid on any
significant early day into Tuesday afternoon convection (cannot
rule out a very stray late afternoon cell forming along a local
breeze once mid to upper 90 convective temps are met). A more
stable Southeast Texas environment will ensure a mainly clear
beginning to the day and this insolation, within high dew point
air in the average middle 70s, will allow ambient temperatures to
warm into the low to mid 90s by noon. Heat indices are forecast to
peak out in the 107 to 111 F range tomorrow afternoon. If you
have the luxury of air conditioning, it is recommended to stay in
it...if outdoor activities can wait until the evening or another
day, a wise choice. If not, find shade and properly hydrate
through the Heat Advisory hours. It is relatively uncommon to
experience very high heat index values such as these in late
Spring. Folks that will suffer from heat exhaustion will likely
do so in these early season heat waves when the body is not
acclimated to the heat.

The approach and passage of a mid week frontal boundary (wind shift)
early Wednesday morning will increase central and eastern forecast
county rain chances to low end pre-dawn PoPs for mainly showers with
isolated thunderstorms.

Here are the Tuesday's record maximum temperature records and
the maximum temperature forecast:

                 Record Max T (Year)     Forecast

College Station     100 (1948)             100
Houston (IAH)        97 (2019)              97
Houston (Hobby)      98 (1956)              97
Galveston            94 (2006)              91

31

&&

.LONG TERM [Wednesday through Monday]...

Should be a dry/quiet period in the wake of the weak cold front on
Tues and the building ridge aloft. While daytime high temperatures
will be near normals, overnight lows could be a few degrees cooler
(for Weds/Thurs nights) as dewpoints fall into the 50s(!). As low-
level moisture slowly creeps back by the end of the week and winds
become more southeasterly, RHs are set to resume their summer time
programming over the weekend. The low/nil POPs are progged to stay
in place for most of the weekend, but there are hints of increased
surges of moisture from the Gulf as the ridge begins to shift more
N/NE with time. Scattered activity could come as early as Sun with
the approach/passage of weak disturbances across the northern Gulf
around the base of the high. 41

&&

.MARINE...

Will keep SCEC flags in place for the coastal waters through tonight
as the moderate/strong SW winds remain in place. This gradient will
be weakening by tomorrow afternoon as a weak cold front moves into/
across SE TX...pushing into the nearshore waters early Weds morning.
Generally light NE/E winds are expected over the bays and nearshore
waters in the wake of the front initially then moderating into an E
flow for Thurs/Fri as high pressure lingers over the Middle/Upper MS
River Valley. Onshore winds are progged to return later in the week
end. No flags/advisories anticipated after Weds. 41

&&

.AVIATION (18Z)...

A few showers and thunderstorms in the area as an outer band of
Cristobal moves across the region. Showers will remain mainly
south of I-10 and thunderstorms are only expected to impact HOU and
GLS. By tonight, the showers and thunderstorms will dissipate leaving
some partly cloudy to mostly clear skies for the night. Tomorrow, a
weak boundary is expected to pass over the area bringing in some
lower clouds but remaining VFR throughout the period. 35

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      78 100  69  93  66 /   0  20  20  10   0
Houston (IAH)              78  97  74  95  68 /  30  10  40  10   0
Galveston (GLS)            82  91  79  91  77 /  20  10  40  20   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from noon to 7 PM CDT Tuesday for the following
     zones: Austin...Brazos...Burleson...Chambers...Coastal
     Brazoria...Coastal Galveston...Coastal Harris...Coastal
     Jackson...Coastal Matagorda...Colorado...Fort Bend...
     Galveston Island and Bolivar Peninsula...Grimes...Houston...
     Inland Brazoria...Inland Galveston...Inland Harris...Inland
     Jackson...Inland Matagorda...Madison...Matagorda Islands...
     Montgomery...Northern Liberty...Polk...San Jacinto...
     Southern Liberty...Trinity...Walker...Waller...Washington...
     Wharton.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION through late tonight for the
     following zones: Coastal waters from Freeport to Matagorda
     Ship Channel TX out 20 NM...Coastal waters from High Island
     to Freeport TX out 20 NM...Waters from Freeport to
     Matagorda Ship Channel TX from 20 to 60 NM...Waters from
     High Island to Freeport TX from 20 to 60 NM.

&&

Short...31
Long/Marine...41
Aviation...35