FXUS64 KHGX 250911
Area Forecast Discussion
National Weather Service Houston/Galveston TX
411 AM CDT Sun Aug 25 2019
- One more day of shower/thunderstorm activity along the coast and
just inland today. Locally heavy rainfall possible.
- Upper level ridge builds Monday/Tuesday and we will need to
monitor heat index values for heat advisory for these days.
- Ridging breaks down through the end of the week. Possible front
Thursday and then maybe stronger front by weekend (ECMWF/CMC).
- TS Dorian in Atlantic. No threat to the Gulf.
.SHORT TERM [Today and Tonight]...
Satellite shows that parts of the area are clearing out late
tonight, while a good chunk of the central portion of our area
remains under a thick veil of cirrus, associated with convection
that has been slowly drifting westward through the evening and
nighttime hours. This convection has stubbornly not died yet, but
is slowly waning as it is passing by College Station.
Meanwhile, an upper trough still sits just offshore over the
northwest Gulf off the coast of Louisiana. The structure in water
vapor imagery isn't quite as impressive as it begins interacting
with a northern stream trough pivoting through the upper Midwest,
but it's still managing to produce showers and thunderstorms over
the Gulf of Mexico.
Without a real big change in environment, the forecast for today
and tonight largely looks like a persistence forecast. Highest
PoPs are restricted to the offshore waters, where it seems a fair
expectation that it will rob land areas of showers and storms
through the day. Given the plentiful moisture that has bled over
Southeast Texas, I do have some fairly decent rain chances near
the coast, but hopefully I've learned something from last night
and went with more modest PoPs farther inland.
Along with the lower rain chances, I'll mirror Saturday's
temperatures fairly closely, with high temps near 90 at the coast,
and well into the 90s far inland. There's probably more to be
said about this being a lead-in for further discussion on the
heat, but will leave that for the long term section to follow.
.LONG TERM [Monday Through Sunday]...
Upper level ridge now over the Desert SW back into the Pacific
should edge east Monday through Tuesday with some positive height
anomolies over Texas by Wednesday. This should lower precip
chances over the area and allow for high temperatures back into
the upper 90s to low 100s. Humidity levels remain high due to
lingering moisture from the weekend. Heat index values could reach
110F again for a good portion of the area. We may need to issue a
heat advisory for Monday and quite possibly Tuesday.
Wednesday into Thursday the GFS/ECMWF continue to show some type
of front to move into the area from the NE. It will be weak but
still possibly cause some shower and storms to form. For now will
keep with 20/30 PoPs each day and high temperatures down just a
touch. Extended range models are still trying to latch onto the
idea of a slightly stronger front getting into SE Texas. ECMWF and
Ensemble have a more favorable pattern for a frontal push but
this seems to be a recent trend. With this being a day 8 forecast,
we will just have to wait/see how the details shake out in future
Southerly winds should continue the next couple of days with
stronger winds at night for tonight and Monday night. Shower and
thunderstorm activity should continue today but decrease tomorrow
and Tuesday. Winds and seas then slack off slightly the rest of
the week with little marine impacts.
As expected, Tropical Storm Dorian has formed in the Atlantic. It
has a small compact center and rather ragged poor convection
around it. Overall forecast remains unchanged from the previous
advisory. There will be some subtle fluctuations in intensity over
the next couple of days as it tries to organize and fight off dry
air. There should be no impacts to the Gulf from TS Dorian.
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 98 79 101 79 101 / 30 0 10 0 10
Houston (IAH) 94 80 97 80 98 / 60 10 10 10 10
Galveston (GLS) 89 84 91 85 91 / 60 30 30 10 10
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