Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Houston/Galveston Texas
1121 am CST Thursday Mar 5 2015
see aviation for 18z taf issuance.
main concern this issuance will be gusty north winds persisting
through the afternoon hours. Organized precipitation has pushed
east of the terminals this morning and clearing line is nearing
cll. Expect gradual improvement in ceilings through the afternoon from
the northwest with strong north winds continuing. All sites
should be VFR by evening with mostly clear conditions and
northeasterly winds around 10kts persisting through the day on
Previous discussion... /issued issued by National Weather Service Lake Charles la/
winds remaining below Wind Advisory criteria over the northeast
sections of the area...however winds still up over the reminder of
the area. Pressure gradient tight enough and therefore have
extended the Wind Advisory to 21z or 3 PM for the existing Wind
Advisory with the exception of Madison and Grimes which will expire
There have Ben isolated thunder in the early morning activity...
however...convection has calmed down and moved off to the east. Expect
rain to continue to dissipate. Temperatures continue to fall into
the low to middle 30s north to the upper 30s to near 40 south. Luckily...
for the most part precipitation has moved out of the cooler areas
so do not expect to see any winter convection with this system
unlike out partners to the east and northeast of US.
Will send out updated zone forecast as soon as possible.
Previous discussion... /issued 439 am CST Thursday Mar 5 2015/
basically two Post-frontal bands of precipitation moving east
across the region during the pre-dawn hours...one larger swath of
light to moderate rain with isolated elevated thunder across the
southeastern County Warning Area and a lighter rain swath over the north central
County Warning Area. Generally...6 hourly rainfall has been a half an inch or
under with localized amounts approaching three quarters of an inch
across downtown Houston. As of now...just liquid precipitation as
surface temperatures across the far northern County Warning Area have remained a
couple of degrees above freezing. The gracious tamu 06z sounding
was indicative of a sleet sounding with a ~3,000 feet sub-freezing
layer below a deep warm layer. As we near sunrise...believe that
any remaining light precipitation that falls north of a Brenham to
Huntsville to Livingston line will be mixed with sleet or maybe
with some light snow. With the coldest air moving in latter this
morning...these counties could experience localized short-lived
light sleet or snow. Due to the precedent warm conditions...no
accumulations of sleet/snow are anticipated with only minor slick
spots making for nuisance traveling conditions. The bulk of the
precipitation will be significantly waning just as the low-middle
layer coldest air arrives...so it all may be a mute point. A
speed maximum exiting northeastern Mexico and traveling parallel to
the Texas coastline this morning will be well northeast of the
state by 18z...with the rrq region of the jet pulling away as
well...so forecast is for greatly diminishing west-to-east rain
chances over the next 8 hours.
The north winds behind last night's boundary have been powerful...
western and coastal counties including the local bays and Gulf
have regularly reported sustained 30g40 knots readings over the last
few hours. Needless to say...but the ongoing Wind Advisory and
Gale Warning will be in effect through noon and 3 PM CST...
respectively. This robust offshore flow will drive water levels
down in the local bays so caution should be exercised for boaters
in the local tributaries/bayous/bays with respect to grounding.
The cold air advection...along with these north winds that will
stay up to around 20 kts for a good part of the day will produce
wind chills in the upper teens to middle 20s. Thus...make sure to
dress in layers if outside in these wintry conditions for any
mentionable length of time. A frigid northern Texas air mass
filtering into the County Warning Area through the afternoon will have today's
temperatures varying by only a degree or two...little to no
warming has many far interior communities stuck in the 30s (and
overnight 20s) over the next 24 hours.
A large near 1040 mb surface high will settle into eastern Texas
early Friday and weaken winds...clearing skies will have the northern
County Warning Area falling to below freezing for approximate 12-14 hours. The
freezing line will near the coast and more southern counties will
experience sub-freezing temperatures for about 6-8 hours. It would
be wise to make the necessary preparations today to protect your 3
p's...people...pets and plants.
Light winds remain east through early next week...thickening
cloudiness with subsequent day(time) warming from friday's upper
40s/low 50s to monday's upper 50s/low 60s. A broad and somewhat
shallow lower western Continental U.S. Trough will place the region within
the warm sector by Sunday. Southwesterly disturbances will pass
over the western Gulf through the first half of next week...keeping
the southern third forecast area/maritime Sunday and monday's probability of precipitation in the
moderate to high category. Despite a possible late Sunday reinforcing
backdoor cold front that will keep northeasterlies in place through
middle-week ... temperatures will warm back up into the
70s by Wednesday. Chilly overnight lows in the upper 40s/low 50s
per a NE flow pattern that will fortify a relatively drier resident
air mass. 31
gale force winds in the wake of last nights cold front will persist
into the afternoon hours. These strong offshore winds will cause
the transport of some water out of the bays and cause tide levels
to run 1 to 2 feet below normal...especially northern portions of
the bays. Gale warnings & low water advisories will remain in
effect today. Speeds will gradually diminish overnight & Friday and
veer to the NE over the weekend.
precipitation should taper off in metropolitan/coastal areas toward 15z...cll/uts
earlier. Ceilings will gradually lift through the day and into VFR territory
between 19-21z and should be sky clear by sunset. Main issue today will
be strong north winds with gusts >30kt. Speed should very slowly
diminish in the late afternoon hours and lose their gustiness after
Preliminary point temps/pops...
College Station (cll) 35 25 50 32 55 / 20 10 10 10 20
Houston (iah) 39 29 52 34 57 / 50 10 10 10 20
Galveston (gls) 42 34 50 41 52 / 60 10 10 10 20
Texas...Wind Advisory until noon CST today for the following zones:
GM...low water advisory from 3 PM this afternoon to 6 PM CST this
evening for the following zones: Galveston Bay...Matagorda
Gale Warning until 3 PM CST this afternoon for the following
zones: Galveston Bay...Matagorda Bay...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.