Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Houston/Galveston Texas
549 PM CST Tuesday Nov 24 2015

ceilings generally between 3500-6000ft should mostly persist
overnight. There will likely be some periods of MVFR ceilings -
primarily toward morning. Guidance suggests some scattering out of
clouds in the middle to late afternoon hours Wednesday. But do anticipate lower
ceilings to develop Wednesday evening as low level moisture deepens. 47


Previous discussion... /issued 312 PM CST Tuesday Nov 24 2015/
a pronounced return to mild conditions will take place over the
next several days as onshore flow increases ahead of developing
system over the Great Basin/rockies. Southeasterly low level winds will
continue to pull modified Gulf air across southeastern Texas and hold
overnight around 60 inland and near 70 along the coast. This will
also set the stage for a warming trend into the end of the week
with afternoon highs in the middle 70s Wednesday and near 80 for
Thanksgiving. With this increasing Gulf moisture...we will also
see a steady increase in rain chances starting Thursday and
increasing over the weekend. The warming air and cooler shelf
waters may also bring some fog back into the region for the later
part of the week.

Models have slowed a bit with the pronounced middle/upper level low
approaching from the west and attendant intrusion of colder air
associated with a surface cold front moving south-southeastward across Texas late
this week. However...combined effect of these features with stream
of middle/upper level moisture from the eastern Pacific could bring quite
a bit of rain to parts of the state. Currently...heaviest rains
will occur to the north and west of our region. However...nearly
everyone should see rain showers in southeastern Texas at some point from
Thursday through Sunday...although the timing and magnitude for
each place remains difficult to pin down. Will keep highest probability of precipitation
across the north and west Friday and Saturday. Low confidence in
high temperatures this weekend as well...especially across the
north...with continued differences in time the cold front

Any reprieve in the wake of this system next week may be brief as
European model (ecmwf) and GFS bring a rather flat and active flow regime aloft...which
could bring another round of wet weather the middle of next week. 48

surface winds across the Gulf waters east to east-southeast with elevated
platforms sampling/reporting more southeast winds. Gradient tighter
near Galveston/42035 and so will issue a short scec there for
winds 15-20 knots. Dewpoints in the 55-61 degree range at 20z over
the Gulf waters with modification of around 1/4 to 1/2 degree per
hour during the last 12 hours. Models all continue this trend and
accelerate this rate during the daylight hours tomorrow. As warm
front lifts back into the area Wednesday this may help to keep winds
backed and flow more easterly over the cooler nearshore waters
increasing the possibility of the first sea fog of the season. SST
at 42035 is 69f but Galveston Bay and coast reporting SST of 58-
62f...though the trajectories should be relatively short crossing
the cooler waters which could offset some of the threat of advection
fog. Windspeeds increasing Wednesday into Thanksgiving day and
although this does tap into even higher dewpoints the trajectories
shorten over the cooler water but this lowered fog threat could
extend down the coast into Matagorda Bay as well. Small Craft Advisory will probably
be needed for Wednesday night/Thursday for winds and seas of 5-8
feet. Gradient slowly relaxes as Pacific cold front begins a slow
March south and finally reaches the coastal waters Sunday probably
after sunrise with relatively light offshore flow.

Tides...continue to exceed astronomical tide levels and are
running 1 to 1.5 feet above normal this afternoon thanks in
large part to the ll easterly flow. As winds veer to the southeast and
increase the tide levels should stabilize around around 1 to 1.5
feet above normal. Total water level around 3 feet may be possible
at high tide times for beach flood prone areas such as High Island.
Rip currents will likely be elevated through Sunday. 45


Preliminary point temps/pops...
College Station (cll) 59 74 64 76 67 / 10 10 20 50 40
Houston (iah) 59 74 66 77 68 / 10 10 20 40 30
Galveston (gls) 66 72 68 74 69 / 10 10 20 30 30


Hgx watches/warnings/advisories...
GM...small craft should exercise caution until 10 PM CST this evening
for the following zones: waters from High Island to
Freeport 20 to 60 nm...waters from High Island to Freeport
out 20 nm.



National Weather Service Glossary of Abbreviations