Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Houston/Galveston Texas
825 PM CDT Tuesday Jul 7 2015
will keep slight chance for a brief rain shower near the coast this
evening...with dry conditions elsewhere the rest of tonight.
Otherwise...forecast remains on track.
Previous discussion... /issued 625 PM CDT Tuesday Jul 7 2015/
still a few isolated cells around southeast Texas...but should be
dissipating with the loss of heating in the next hour or two.
Otherwise...VFR for most of the night - maybe a few hours of MVFR
ceilings near cll late. Otherwise...a continued forecast of persistence
will probably be tough to beat. 47
Previous discussion... /issued 251 PM CDT Tuesday Jul 7 2015/
radar showing scattered showers this afternoon...and a few
lightning strikes with pulse storms moving quickly north with
southerly flow. Should see this convection diminish late this
afternoon with loss of daytime heating. Cant rule out an isolated
streamer shower coming off the Gulf overnight...as occurred last
night...but should again be limited as far as coverage.
For Wednesday and Thursday...airmass not as moist as today as
indicated by lower precipitable water values in the models moving
over the area. Model soundings also show this drier air off the
surface and a weak capping inversion so think tomorrow will be
mainly dry during the day Wednesday and Thursday. Should remain
hot and humid although afternoon dewpoints will likely be a few
degrees lower than today given possibility of mixing some of the
drier air aloft down to surface.
For Friday through the weekend...mean layer moisture begins to
increase again but not expecting any more than 20 to 30 percent
coverage with mostly diurnal convection...morning at coast...and
afternoon inland...much like we have today. Not a wash out by any
means. Coverage inhibited by ridging aloft and at surface. 46
the 1020 mb high centered over Florida is creating a tight enough
onshore pressure gradient...in relation to a Western Plains
trough...to generate a more moderate southerly wind. The presence of
a low level jet may also be a contributor to the overnight
strengthening of onshore winds as these stronger winds mix down to
the water's surface. Small craft exercise caution flags will remain
up in the short term to account for these near 15 knot Gulf winds...
responding elevated seas that will generally range from 3 to 4 feet
nearshore...4 to 5 feet across the far offshore waters. Eastern high
pressure will expand further west at week's close and weaken onshore
winds...lower seas through the upcoming weekend. 31
Preliminary point temps/pops...
College Station (cll) 77 94 76 93 74 / 0 10 10 10 10
Houston (iah) 78 94 76 92 75 / 0 10 10 10 10
Galveston (gls) 81 90 81 89 80 / 20 10 10 10 10
GM...small craft should exercise caution until 7 am CDT Wednesday for
the following zones: waters from Freeport to the Matagorda
Ship Channel 20 nm to 60 nm...waters from Freeport to the
Matagorda Ship Channel out 20 nm...waters from High Island
to Freeport 20 to 60 nm...waters from High Island to
Freeport out 20 nm.