Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
729
FXUS64 KHGX 270914
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
414 AM CDT Sat Aug 27 2016

.DISCUSSION...
At 3 AM, a weak trough of low pressure was just south of the
Sabine River delta. Patchy light rain continues over the northern
zones with slightly stronger convection over the NW Gulf of
Mexico. No discernible features at 850 MB but moisture was
plentiful with 850 MB dew points between 15-17 C. A weak upper
level low was noted just east of Brownsville at 300 MB. This
feature shows up well on water vapor. There appears to be a plume
of moisture on the east and north side of the upper low taking aim
directly at SE TX. Two disturbances noted in the flow. The first
disturbance should bring a round of shra/tsra to the extreme upper
coast this morning, with a break this afternoon. The second
disturbance will approach this evening and linger overnight. The
second disturbance coupled with a developing but weak surface low
over the western Gulf will accompany PW values between 2.20 and
2.35 inches and provide the area with periods of showers and
thunderstorms. Areas along the coast will likely see some heavy
rain tonight into Sunday. A Flash Flood Watch may be required
tonight for areas near the coast. The Texas Tech WRF is
particularly worrisome (it verified well yesterday) as it is
stronger with the surface low and maintains a low level
convergence zone over the coastal counties for a solid 24 hours.
The surface feature eventually drifts southwest and away from the
from the region early Monday. SW zones will likely still be
affected by the slow moving surface low on Monday. Again the TT
WRF is the most aggressive and continues to slowly strengthen the
surface low as it moves SW along the coast. Deep moisture will
continue to be pulled into the MAtagorda Bay region through Monday
morning.

Even though the surface low drifts southwest, SE TX will still be
influenced by a weakness aloft. PW values remain near or above 2.00
inches so scattered showers and storms expected to continue
Tues-Thurs with daytime heating as the primary catalyst.

An expanding ridge over the central plains will begin to influence
the region late Thursday into the weekend. Heights only build to
591-592 DM so still expect isolated showers but coverage will be
considerably less. Another inverted upper trough will approach
from the east next Sunday and will bring rain chances back to SE
TX. 43

&&

.MARINE...
Bit of a tricky forecast. A lot will be determined on if a surface
low will form during today or tomorrow. For now, a broad upper level
low off the lower and mid Texas coast was helping to funnel moisture
across the upper coast. A model consensus keeps easterly to east-
northeasterly winds in place through Tuesday morning.

The impacts should mainly be seen in the tide levels along the
coast. Current tide levels ranged from one-half to one foot above
the astronomically predicted normal levels. These may rise another
half a foot. Again, a lot will be determined by any surface low
formation and its location and upon the strength of the surface
winds. The models have been fairly consistent in developing near
caution conditions today, diminishing the winds tonight through
early Monday, and then redeveloping near caution conditions late
Monday into early Tuesday. The seas do not look to get above 2 to 3
feet.

Mariners should continue to monitor the latest tropical weather
updates from the National Hurricane Center.

40

&&

.CLIMATE...
Hobby Airport received 0.07 inches of rain yesterday and that
makes 14 consecutive days with measurable rain. City of Houston
Aug rainfall is up to 10.30 inches, still 6th place but only 0.44
inches shy of reaching the 4th wettest August on record.

&&

Tropical...
A trough of low pressure over the northern Gulf is currently
expected to be extratropical in nature, and the main focus should
be on the rainfall potential near the coast. Still, NHC has given
this area a 10 percent chance of becoming a tropical cyclone, as
the upper trough could generate surface low pressure.

Farther east, Invest 99L continues to look ragged and
disorganized. However, this invest should continue to be
monitored. No direct impacts are forecast for SE Texas at this
time. As a reminder, late August through mid September is the
climatological peak of the hurricane season. Southeast Texans
should make sure they keep up with the forecast and hurricane
preparedness regardless of whether or not a system is in or
approaching the Gulf of Mexico. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      89  74  87  74  89 /  40  20  50  30  50
Houston (IAH)              88  74  87  74  88 /  40  40  60  40  50
Galveston (GLS)            86  78  86  79  86 /  70  70  70  70  60

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.