Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 031138
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
638 AM CDT Mon Aug 3 2020

.AVIATION [12Z TAF Issuance]...

Some patchy fog has developed at CXO, LBX and SGR this morning
briefly bringing visibility down to 2 to 4 miles, but this fog
will dissipate by mid morning as the rising sun. Isolated showers
and thunderstorms will again be possible this afternoon into the
evening hours that may produce locally gusty winds. The terminals
that have the highest chances of seeing some VCTS are CXO, IAH,
and HOU. Activity decreases overnight tonight with some patchy
ground fog developing again. Overall, VFR conditions prevail
through the period.

Fowler

&&

.PREV DISCUSSION /Issued 357 AM CDT Mon Aug 3 2020/...

.SHORT TERM [Through Tuesday Night]...

Lingering moisture has lead to some patchy ground fog to develop
across the southwestern counties and low lying spots around the
area this morning, but this fog should dissipate shortly after
sunrise. Showers and thunderstorms will again be possible across
most of the area today as PWATs remain around 1.5 inches and
convective temperature in the low to mid 90s, which will be
reached fairly easily by the early afternoon. There is not much
CAPE available this afternoon, so not anticipating much of a
chance of severe weather. However, model soundings show a fairly
distinct inverted-V profile, so any thunderstorms that do form
will have the chance of producing some gusty winds. And if those
gusty winds collide with the sea breeze, then you can expect some
additional thunderstorm initiation (like yesterday). Both the NAM
and GFS are showing some lingering low level frontogenesis from
the seabreeze in northern Harris County into Montgomery county
into the late evening hours, so have left some lingering 20 PoPs
in that area into the evening. Activity will wind down overnight
tonight into Tuesday morning. A very weak upper level shortwave
with an slight uptick in PWATs to 1.6 to 1.7 inches will move
through the area Tuesday afternoon that will again lead to a
chance of afternoon showers and thunderstorms.

High temperatures will get into the mid to upper 90s today and
Tuesday for most of the area with the coast staying a bit cooler
with highs in the upper 80s to low 90s. Triple digit heat remain a
possibility for portions of Burleson and Brazos counties.
Persistence will be key with the low temperatures remaining in
the mid to upper 70s.

Fowler


.LONG TERM [Wednesday Through Monday]...

An upper level ridge over the southern Rockies will amplify and
expand into Texas as an upper level trough over the Great Lakes
shifts east. The upper flow between these two features will be out
of the N-NW and a series of weak upper level disturbances will move
into SE TX from the north on Wednesday. The GFS fcst sounding does
not show much capping with PW values topping out at 2.07 inches.
Convective temperatures are in the mid 90`s which looks reachable.
NAM12 soundings show something similar so it seems reasonable to
maintain rain chances over mainly the eastern half of the CWA closest
to the track of the upper level disturbance.

The upper ridge shifts further east Thursday through Saturday and
the amplified upper flow dampens out. Despite increasing subsidence
with the ridge, ample low level moisture trapped beneath the ridge
should still allow for isolated diurnally driven showers and storms.
The GFS and ECMWF both show a slightly stronger upper level ridge
than they did yesterday with 500 heights building to 594-595 dm.
Despite the building heights, 850 temps only slowly climb from 18.6
on Thursday to 20.4 C by next Monday. Considering the increase in
500 heights and the time of year, went above MEX/NBM guidance for
MaxT for the second half of the week and next weekend. Will forecast
highs in the mid/upper 90`s area wide. Heat index values will also
be on the rise and could reach values between 103-106 degrees later
this week. Global models continue to hint at a weak upper level
inverted trough approaching the area early next week. Will carry
slight rain chances for next Mon/Tues. 43


.MARINE...

Generally light onshore flow and low seas are expected through the
week as high pressure builds over the Gulf. Isolated showers and
thunderstorms will be possible thanks to heating, but coverage will
be much more limited compared to the past few days.

Fowler

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL)  98  75  98  76  99 /  30  20  10   0  10
Houston (IAH)          96  77  98  76  96 /  40  30  20   0  20
Galveston (GLS)        90  80  90  81  93 /  20  20  20   0  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...None.
GM...None.

&&

$$


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