Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 132030

Area Forecast Discussion
National Weather Service Houston/Galveston TX
330 PM CDT Sun Jun 13 2021

.SHORT TERM [Today through Monday Night]...

Seabreeze very slowly creeping inland against the westerly wind
with heat piling up. Heat Advisory in effect with heat index readings
104 to 109. Looking for a few storms to pop off mainly south of the 69
corridor. Also can see a gravity wave moving southeast through the
region this afternoon and that looks to be coincident with the sea/bay
breeze around 22-23z not sure it will enhance the potential though
for storms.  Elevated V soundings and so expect some spotty winds near
these that could go 40+mph. Storms should wane this evening and
then some redevelopment of showers toward morning.

Monday anticipating greater coverage as next s/w moves west through
the region and soundings remain moist and unstable. Temperature may
be a degree or two cooler with a little more cloud cover. Don`t
think we will need another heat advisory. Storms should be slow movers
with the typical summertime heavy downpours.


.LONG TERM [Tuesday through Sunday]...

With Southeast Texas wedged between an upper level ridge to our
west centered over the Four Corners region and an upper level
trough to our east along the Mid-Atlantic and Northeast, any
fluctuations in this wave pattern will influence our rain chances
this week. However, the overall consensus is that a few upper
level disturbances will push into SE Texas on Tuesday and
Wednesday. With weak surface flow, the sea breeze is expected to
push inland each afternoon, creating a mesoscale lifting mechanism
for afternoon convective clouds to evolve into stronger afternoon
showers and thunderstorms. These weak disturbances moving through
could also act as an additional lifting mechanism. Therefore,
kept in generic PoPs throughout the day on Tuesday and Wednesday,
peaking in the afternoon, and higher PoPs along I-10 and the

By Thursday, an inverted upper level trough towards our south will
begin to wedge itself over SE Texas and push the upper-level ridge
to our west even further west. This strengthening inverted trough
will help move the disorganized area of showers and thunderstorms
currently over the Bay of Campeche to the north. The National
Hurricane Center is predicting this area has a 50% chance of
developing into a depression within the next five days, which
agrees with the trends we have been seeing in global models. With
the latest deterministic runs, the GFS has backed off on this
system`s intensity and organization, and now is in closer
agreement with the ECMWF showing a weaker, less organized, and
very sheared system, with it`s moisture plume placed to the east
of the closed low and primarily over Louisiana. Meanwhile, the
GFS and ECMWF depict SE TX on the drier, west side of the low.
Wraparound precip from northerly flow is still possible for our
area, but most of the rain chances and moisture appear to be
towards our east. That being said, models typically have a hard
time handling these weaker systems, especially when these systems
encounter high wind shear and have competing areas of low
pressure as it tries to get more organized. Therefore, a lot can
still change until this system gets more organized and models can
initialize better. Any fluctuations in the placement of the closed
surface low will greatly influence the impacts our area gets. In
the meantime, kept in generic PoPs of 20-40% this weekend until
more of a consensus can be reached.

Keep in mind, these systems tend to be sneaky and when they do
get more organized, we don`t have as much of an advanced warning
as we would typically like to see for a tropical system, so it is
important to finalize any hurricane preparations and stay up to
date with the latest forecasts from our office and the National
Hurricane Center.


A weak high pressure is still over the western Gulf of Mexico
which is generating a light W-SW flow across our coastal waters
today and this wind will prevail through tomorrow as well. Winds
will be light and variable on Tuesday until onshore flow resumes
by late Tuesday. Afternoon showers and thunderstorms are possible
each day this week, but any outflow boundaries from this
convection could push into our coastal waters, so mariners should
stay vigilant for sudden wind gusts and a change in wind direction
with this afternoon activity. Meanwhile, a disorganized low in
the Southwestern Gulf will meander northward and start to impact
our coastal waters toward the weekend. Ahead of this system, expect
swells, building seas, gusty winds, and widespread showers and
thunderstorms as this system approaches. More specific impacts
remain uncertain, so mariners should closely monitor tropical and
marine forecasts in the coming week.


No significant changes regarding the tropics since the previous
discussion. The National Hurricane Center is still monitoring a
disorganized area of showers and thunderstorms in the Bay of
Campeche. Formation chance in the next 2 days is low at 20% and
the formation chance in the next 5 days is medium at 50%. Forecast
tracks, intensity, and specific impacts for Southeast Texas
remains uncertain at this time, but a general northward
progression of this system is expected starting the middle of
this week. In the meantime, be prepared and stay up to date with
the latest forecasts from our office and the National Hurricane


College Station (CLL)      95  77  95  75  95 /   0   0  30  20  20
Houston (IAH)              95  77  96  77  95 /  30  30  40  20  30
Galveston (GLS)            91  80  91  80  90 /  20  20  30  20  20




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