Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Houston/Galveston Texas
747 PM CDT Wednesday Mar 12 2014
a little cirrus moving in from the west and winds quickly
relaxing. Updated the zones to remove the Wind Advisory. Splendid
evening across the area with a cool start tomorrow morning.
Previous discussion... /issued 558 PM CDT Wednesday Mar 12 2014/
see aviation for 0z taf issuance.
VFR conditions expected through taf period. 23
Previous discussion... /issued 325 PM CDT Wednesday Mar 12 2014/
the zonal flow aloft will become southwesterly over Texas by the
upcoming weekend as an upper level trough forms over southern
rockies. The models agree with moving a series of shortwave
troughs along the flow across the state beginning late Friday
through early Monday. The models were in decent agreement with the
pattern aloft and at the surface during this period...but then
begin to disagree early next week.
Short term impacts to consider are the winds for the remainder of
this afternoon...and temperatures tonight. The strong pressure
gradient and cold air advection will relax late this afternoon.
The nam12...mav...met...and lav guidance all agree with wind
speeds lowering to below Wind Advisory criteria between 4 and 6
PM. For that reason...will trim the advisory back an hour to end
at 6 PM. Most inland locations will probably see diminishing winds
around 4 PM except for the western areas and the two tier of
counties near the coast. The guidance and NAM bufr both forecast
temperatures tonight to fall into the middle 30s away from the
coast. This looks reasonable given the clear skies and diminishing
The nam12...GFS...and European model (ecmwf) all agree with some isolated rain
chances Friday and then better chances on Saturday. Do not think
thunderstorms will be possible until Saturday afternoon when the
best vorticity advection occurs aloft ahead of the stronger
shortwave trough. A cold front will then move across the forecast
area Sunday with some lingering rain possible into early Monday.
Confidence level for the Monday through Wednesday part of the
forecast is low given the differences between both the GFS and
European model (ecmwf).
high pressure will build over the state tonight and winds will
begin to relax over the bays but remain rather brisk over the
Gulf. Will maintain the Small Craft Advisory for the Gulf waters through 06z. The
high will move east on Thursday and onshore winds will return by
afternoon. Onshore winds will increase Friday into early Saturday
ahead of a weak shortwave. A boundary will move through southeast Texas on Sunday
with a moderate to strong offshore flow developing. Onshore winds
will redevelop Monday night as low pressure moves across the
Central Plains. Tide levels are around 1.0 to 1.5 feet below
normal over the upper reaches of Galveston Bay. With offshore
winds relaxing...don't think a low water advisory will be needed
for the evening. 43
Previous discussion... /issued 1209 PM CDT Wednesday Mar 12 2014/
VFR conds for the next 24 hours. Winds are expected to decouple
after sunset and veer to the southeast on Thursday. 43
Preliminary point temps/pops...
College Station (cll) 37 66 46 68 56 / 0 0 10 20 20
Houston (iah) 39 65 46 69 57 / 0 0 10 20 20
Galveston (gls) 47 62 54 65 60 / 0 10 10 20 20
GM...small craft should exercise caution until 4 am CDT Thursday for
the following zones: Galveston Bay...Matagorda Bay...waters
from Freeport to the Matagorda Ship Channel out 20 nm...
waters from High Island to Freeport out 20 nm.
Small Craft Advisory until 4 am CDT Thursday for the following
zones: waters from Freeport to the Matagorda Ship Channel
20 nm to 60 nm...waters from High Island to Freeport 20 to