Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Houston/Galveston Texas
702 PM CST Thursday Feb 11 2016

00z sounding showing the ll moisture working in across the
southern 1/3rd of the region as of 00z. As winds relax and
moisture intrudes a little further northeast and perhaps north
if/as winds back slightly especially near the coast the pattern
appears to be favorable for radiation fog. Have added areas of
fog to the south and delayed the onset across the north until
around 2 am. Across the south it may start closer to midnight
inland and then shortly after for sea fog. Still uncertain about
how thick the fog will get but many of the ingredients are in
place for fog development. Can't rule out the formation of dense
fog after midnight but will be keeping a close eye on it.



Previous discussion... /issued 551 PM CST Thursday Feb 11 2016/

the main aviation concerns for the 00z tafs center around the
development of fog near the terminals overnight... creating at
least temporary IFR to MVFR ceiling and visibility restrictions
Friday morning.

VFR conditions are expected across the terminals generally
through 06z... with returning low level moisture /dew points in
the middle 50s to near 60 along the coast and over the Gulf/ pooling
ahead of a stalled boundary draped across central Texas.
Anticipate favorable conditions for radiation fog development
overnight with clear skies and southerly winds less than 5 knots
in place... but have low confidence in which areas will see the
lowest visibilities with forecast soundings maintaining at least
25 to 35 knot southwest winds just off the surface. Think enough
mixing will be able to occur with these winds to inhibit more
widespread fog development and kept trends in previous taf the
same with at least patchy fog development /and IFR to MVFR
restrictions/ beginning around 09z and persisting through 15-16z.

VFR conditions are expected to prevail for the remainder of the
taf with south/southwest winds increasing to 7 to 10 knots during
the day on Friday. A disturbance skirting the Southern Plains late
in the taf period looks to provide enough of a push to the stalled
boundary to bring a light northerly wind shift to the terminals
around 18 to 21z at College Station/Huntsville and after 00z for
the Houston terminals.


Previous discussion... /issued 322 PM CST Thursday Feb 11 2016/

a general northwesterly flow aloft will affect the area over the
upcoming weekend and into the middle of next week. This will help
push a frontal boundary over the area later this week...although
the front will stall out over southeast Texas and the northwestern Gulf
this weekend before moving offshore on Monday night. The best
chances of rain will be on Sunday and Monday as an upper level
shortwave moves along the flow across the state. A fairly large
cap will be in place but should erode enough for isolated
thunderstorms to be possible late Sunday night into Monday...
especially along and ahead of the main vorticity maximum on

With the near surface moisture on the seen by increasing
dewpoints...some patchy fog will be possible overnight tonight and
Friday morning. The high res short term models and the guidance
are all showing the best time period to be from midnight tonight
through sunrise with the fog lifting by middle morning. If sea fog
develops and moves onshore...the fog may linger over the coastal
areas longer. Conditions do not look to be as conducive Saturday
night as a surface boundary will move through all but the
southwestern set of counties. A northerly surface flow will likely
set up in the wake of the weak front.

Temperatures will continue to be warmer than normal. If the winds
become more southwest than expected on Friday...could once again
see some afternoon highs reach the upper 70s to possibly near 80. expecting more of a southerly wind. Some cooling is
expected after the frontal passage on Sunday and again starting on
Tuesday. Even with the slightly cooler airmass...temperatures will
continue to be above normal for the most part through the middle
of next week. Some locations in the far inland areas may
experience near normal temperatures on Saturday and Sunday...and
again on Tuesday.


gusty SW winds will diminish after sunset near the coast and bays
but will probably take a bit longer further offshore. Will
maintain caution flags for now. Speeds should diminish late
tonight and Friday. A warmer airmass moving over the cooler shelf
waters may produce patchy fog at night and in the morning through
Friday. A cold front will backdoor into the region Friday night
and Saturday with strengthening east to northeast winds and
building seas developing in its wake. Southeast winds return on
Saturday night and Sunday. Another cold front should push off the
coast sometime on Monday. 47

may see some shallow ground fog overnight into the middle morning
hours on Friday. Otherwise...relative humidities will continue to
slowly moderate on Friday. Values should bottom out between 30-45%
northwest of Highway 59 on Friday and 45-65% further southeast. Wind speeds
should be quite a bit lower than they were today as well...
especially the gustiness. 47


Preliminary point temps/pops...
College Station (cll) 51 74 48 67 49 / 0 0 0 0 10
Houston (iah) 55 77 50 68 48 / 0 10 0 10 10
Galveston (gls) 58 71 55 64 54 / 0 0 0 10 10


Hgx watches/warnings/advisories...
GM...small craft should exercise caution until 3 am CST Friday 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 60 nm.




National Weather Service Glossary of Abbreviations