Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 260309

Area Forecast Discussion
National Weather Service Houston/Galveston TX
909 PM CST Sat Feb 25 2017

Current forecast looks to be on track. Onshore flow are expected
to begin strengthening early tomorrow morning (through the after-
noon) as a shortwave moves across the SW U.S. (into the Southern
Plains) and helps tighten the pressure gradient. The increased S
and SE winds will draw deeper moisture up from the Gulf and isol-
ated/widely scattered SHRAs will be possible across SE TX by the
afternoon tomorrow. 41


.PREV DISCUSSION...  /ISSUED 401 PM CST Sat Feb 25 2017/

Eastern OK/northeastern TX centered surface ridging providing the
subsidence needed to keep skies clear...allowing many interior
sites to warm into the average middle to upper 60s. High pressure
will advance eastward into the southeastern U.S. through Sunday...
veering evening northeasterlies to southeasterly through the
morning. Albeit a much weaker offshore pressure gradient but still
tight enough to maintain a near 5 to 10 knot overnight breeze
under mainly clear skies as temperatures fall into the inland
middle to upper 40s...coastal mid to upper 50s under a more brisk
easterly wind. Increasing humidity/clouds from the south and west
tomorrow as winds stick out of the southeast and strengthen
tomorrow afternoon. Sunday`s weather pattern of warm air advection
increases north and western CWA precipitation chances to slight
or low end probabilities. Any precipitation under mainly overcast
skies will be light...probably either short lived showers or
periods of light rain and/or more warm humid air
overruns a modifying cooler lower level dome of air. Despite the
cloudiness and stronger southerly flow...Sunday`s afternoon
temperatures will likely top out in the lower to middle 70s.

The medium range (through mid week) mid to upper level pattern is
fairly benign with no significant amplification...a near zonal
pattern across the central CONUS. Modeled upper ridging over the
Gulf appears to hold its ground as a trough rides up and over
along its eastward trek out of the Rockies Wednesday. There should
be enough lower level moisture just downstream of its associated
cold frontal boundary to increase northern county shower with
embedded storm chances as early as Tuesday afternoon. Cooling mid-
levels through the first half of Wednesday will steepen lapse
rates and increase regional thermo indices enough to forecast more
numerous thunderstorms within the warm sector along or just ahead
of the passing (pre) frontal boundary during the day Wednesday.
The front should be to the coast by sunset Wednesday with moderate
evening offshore winds. Leading the front...daily temperatures
will warm back into the very familiar mean lower to middle 80
maximums/middle 60 minimums Monday and Tuesday. The cooler and
drier post-frontal air mass will have the late week diurnal T
curve maxing out in the average upper 60s and bottoming out in
the mean middle to upper 40s/coastal middle 50s.

The long range pattern is progged to turn more overcast and wet
through next weekend. An upper low off the California coast will
move ashore over the Baja region early Friday. Both the GFS and
Euro evolve this feature into an upper wave trough and push it
into western Mexico Saturday...forming a downstream surface trough
over and offshore of southern Texas. More enhanced lower to middle
level near coastal convergence will increase southern TX/Coastal
Bend precipitation chances through the day Saturday. At least overcast
with southwestern CWA/western water showers...a cool start to next
weekend with slightly above normal afternoon warmth to near 70
degrees. 31


College Station (CLL)      44  72  62  82  65 /  10  30  50  30  10
Houston (IAH)              47  74  66  83  68 /  10  20  50  40  10
Galveston (GLS)            58  72  66  77  68 /  10  20  40  40  10


     for the following zones: Waters from Freeport to the
     Matagorda Ship Channel from 20 to 60 NM...Waters from High
     Island to Freeport from 20 to 60 NM.


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