Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
FXUS64 KHGX 050534
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1134 PM CST Sun Dec 4 2016
Lowering ceilings and visibilities (IFR/LIFR) are anticipated to develop
mainly during the overnight through morning hours as periods of -RA
with embedded SHRA/TSRA move into the area from the southwest and south
in association with the upper level low moving into central Texas and
a surface low developing off the Texas coast. Winds should be mainly
N to NE, and gusty closer to the coast. Look for rains to come to an
end area wide tomorrow afternoon and evening. Improving ceilings could
quite possibly hold off until tomorrow night or Tuesday morning. 42
.PREV DISCUSSION... /ISSUED 805 PM CST Sun Dec 4 2016/
Forecast is on track, with only very small tweaks made to keep the
forecast in line with observations and trends observed in the
consensus of short term models.
The crux of forecast continues to ride on continuing rainfall
potential as a surface low coalesces on the coastal boundary, and
moves northeastward while the upper low ejects. Growing consensus
in the heaviest rain falling offshore, and am cautiously
optimistic that only light to moderate rain showers are in store
for land areas. However, a small shift inland could bring the
developing low`s warm front/warm sector over the coastline, and
bring some heavier rain to areas that have already seen
significant rainfall this weekend. Because conditions imply
diminished tolerance for forecast error, will leave the slimmed
down flash flood watch in place until there is greater certainty
that the heaviest rains will fall over the Gulf. Finally, some
convergence at 850 mb could enhance rainfall somewhat tomorrow
morning over our north/northeast, but with some lesser rainfall
totals for most of that area, ground conditions should be enough
to absorb remaining expected rainfall.
Low pressure is forecast by a model consensus to form off the lower
Texas coast and then move up into the upper Texas coastal waters
later tonight and on Monday. As it does so, a warm front will move
to just along the immediate coastline. The pressure gradient was
already tightening up at mid afternoon with advisory conditions in
place over the offshore waters. Gusts up to near 30 knots are
possible tonight. Winds will diminish on Monday as the low moves
east of the area.
Tides are forecast to approach 2.8 feet at the time of high tide
early this evening at the Galveston Bay Entrance. More easterly
winds are expected to develop this evening, but the tide will be
falling throughout the late evening and overnight period. During the
time of high tide early this evening, wave runup may help to cause
some minor flooding especially along gulf-side low-lying locations
and highways along the immediate coast.
Later this week, a strong cold front is expected to move off of the
coast Wednesday night. Strong offshore winds behind the front may
gust to gale force by overnight Wednesday night through most of the
day on Thursday.
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 49 58 45 69 46 / 70 80 10 0 0
Houston (IAH) 52 60 49 70 50 / 70 80 10 0 0
Galveston (GLS) 56 66 58 68 62 / 70 80 10 0 0
TX...Flash Flood Watch through Monday morning for the following
GM...SMALL CRAFT SHOULD EXERCISE CAUTION through Monday morning for
the following zones: Galveston Bay...Matagorda Bay.
Small Craft Advisory until noon CST Monday for the following
zones: Coastal waters from Freeport to the Matagorda Ship
Channel out 20 NM...Coastal waters from High Island to
Freeport out 20 NM...Waters from Freeport to the Matagorda
Ship Channel from 20 to 60 NM...Waters from High Island to
Freeport from 20 to 60 NM.