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FXUS64 KHGX 192027

Area Forecast Discussion
National Weather Service Houston/Galveston TX
327 PM CDT Mon Oct 19 2020

.SHORT TERM [through Tuesday Night]...

Ongoing scattered showers and isolated thunderstorms will continue
through early this evening. This is in response to a stalled frontal
boundary which is increasing low to mid level moisture (PWs 1.5 -
2.0 inches) and decent instability (around 7C/km) northward across
our region. This weak front is currently located near Palestine into
Austin, TX and looks like we will remain in the warm sector until
this front weakens/disappears. Therefore, expect this activity to
continue through sunset, then the main focus will be within the
convergence zone of the frontal boundary where spotty rain/drizzle
will be possible through the night. With light winds and a moist
boundary layer, low stratus and possibly some patchy fog are
expected to spread across the region later tonight into early

A weak mid-upper level vort max over western Texas will continue to
ride the quasi-zonal flow aloft tonight, reaching our forecast area
on Tuesday. Again, this upper-level forcing combined with a warm and
moist Gulf airmass will bring rain/storm chances. The best
opportunity will be south of I-10 in the morning, and east of I-45
in the afternoon. Above normal temperatures are expected with highs
mainly in the mid to upper 80s. 05


.LONG TERM (Wednesday through Monday)...

On Wednesday, the upper flow over Texas will be kind of flat as
the region lies on the western periphery of an upper high over the
eastern U.S. and a weak short wave over the western plains. At the
surface, weak low pressure will be over the southern Gulf of
Mexico and this feature will allow for onshore winds to persist.
The air mass will remain humid so can`t rule out an isolated
shower from time to time but the lack of a well defined boundary
and upper level support should keep most areas dry. Not a lot of
day to day change through the end of the week as temperatures
remain 5 to 10 degrees warmer than normal. A weak cold front will
cross SE TX on Saturday but convergence along the front looks weak
and PW values are meager, reaching only around 1.20 inches. Will
keep the fropa dry for now but will watch trends as we near the
end of the week. We should get a brief cool down on Saturday in
the wake of the front with weak CAA but temperatures warm right
back up again on Sunday as onshore winds return. Warm and humid
conditions are expected Sunday and Monday as weak upper level
ridging over the Gulf expands into Texas. Another cold front is
expected to cross SE TX on Tuesday but both the GFS and ECMWF hang
the upper level support to the west so the front will probably be
a slow mover and the Canadian does not bring the front through
until next Thursday. Ensemble guidance also seems to favor the
slower solutions. 43



High pressure east of the region will allow for an onshore flow
tonight. As weak low pressure develops over the southern Gulf, the
flow between the high to the east and the low will allow for
surface winds to back to the east and an east wind will then
persist into Friday. A cold front will cross the coastal waters
early Saturday and winds will back to the NE. High pressure
building into the southern plains behind the front will move east
very quickly and onshore winds will redevelop by late Saturday
night. Onshore winds will then prevail through early Tuesday.

Water levels could briefly reach 3.5 feet above MLLW on Wednesday
as a persistent east wind brings slightly elevated water levels
to the coast. Tides will probably remain near or just above 3.0
feet at high tide through the end of the week due to the
persistent east wind. 43


College Station (CLL)      71  87  68  86  66 /  20  10   0  10   0
Houston (IAH)              71  85  70  86  69 /  10  10  10  10   0
Galveston (GLS)            74  82  74  83  75 /  20  20  10  10  10





NWS HGX Office Area Forecast Discussion