Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 130315

Area Forecast Discussion
National Weather Service Houston/Galveston TX
915 PM CST Sun Nov 12 2017

The weak frontal boundary was moving into the western part of the
forecast area at mid evening. Made a few tweaks to temperatures
but think any isolated rain chances will be ending soon per the
previous forecast.



.PREV DISCUSSION... /ISSUED 534 PM CST Sun Nov 12 2017/

AVIATION [00Z TAF Issuance]...

Satellite imagery shows plenty of mid and high level clouds over
SE Texas. Based on surface analysis, the frontal boundary has been
tough to find but appears to be stretching from west central Texas
to east Texas this afternoon. The front may be just reaching KCLL
with winds turning more to the NNE in the last hour. Front will
slowly push through relatively unnoticed tonight and may shift
winds to the NE. With ceilings staying at VFR levels and winds
really not increasing above 10 knots, TAFs will stick with mainly
1 line. High clouds will be increasing as anticyclonically curved
jet develops over the region tomorrow.


PREV DISCUSSION /Issued 338 PM CST Sun Nov 12 2017/...

Scattered to numerous showers continue in the vicinity of an area
of a meso-low that has developed south of Matagorda Bay this
afternoon. Expect highest rain chances to remain relegated to
areas around and south of Matagorda Bay through the rest of the
day before an approaching inverted trough in the Gulf
approximately 150 miles to the east (per surface analysis) reaches
the Lower Texas coast later tonight. A few light showers may
still be possible across the extreme northern counties, but
weakening isentropic lift on the 300-305 K surfaces as the Gulf
trough passes and a weak cold front approaches should limit those
chances through this evening. The front has made little progress
across North Texas this afternoon but may sag a little farther
south this evening before washing out near the region tonight. As
a result, the front is expected to have little impact on
temperatures (or rain chances) with overnight lows in the mid 50s
to mid 60s.

Dry northwest flow will persist across the region on Monday and
Tuesday as an upper ridge remains centered southwest of the
region, with above normal temperatures returning to the region as
a result. Highs are forecast to be about 5-10 degrees above
seasonal normals as they climb into the mid to upper 70s with
lows nearly 10-15 degrees above normal for this time of year in
the mid 60s to near 70. Isolated streamer showers may be possible
Wednesday and Thursday as onshore flow begins to strengthen.
Onshore flow continues to strengthen on Friday in response to
surface cyclogenesis over the High Plains and associated strong
warm air advection ahead of this system may result in the region
approaching or reaching record high temperatures on Friday (lower
to mid 80s).

Above normal warmth will quickly come to an end as the surface
cyclone ejects across the Plains and drags a strong cold front
across the region sometime late Friday or Saturday. Deterministic
medium range guidance still continues to offer timing differences
for the arrival of this front (12Z European about 12 hours behind
the GFS) and this timing would affect not only temperatures on
Saturday, but the potential for thunderstorms with the front. A
faster cold front (GFS solution) would bring a quick shot of rain
Friday night as the front moves through the region, with a slower
front (European solution) allowing for enough moisture return
ahead of the front to provide some instability along the coast and
across the coastal waters for thunderstorm development. Have opted
to go with a blended solution of guidance for frontal timing and
have inserted a mention of isolated thunderstorms along the coast
for Saturday. Behind the cold front, expect temperatures to return
back to seasonal normals through the remainder of the weekend.


Waters are just downstream of an approaching cold front that has
backed today`s light to moderate winds northeast. This front is
forecast to make its way across the waters tonight and fortify a
moderate northeast wind pattern Monday. Tomorrow...the post
frontal coastal parallel pressure gradient will tighten up and
produce brief SCEC conditions over the far offshore Gulf waters.
These amped up northeasterlies will generate average 3 to 4 foot
nearshore...near 5 foot offshore...wave heights through Tuesday
morning. Winds veer back around to southeast by late Tuesday and
will remain onshore through Friday...strengthening and veering
more southwest Friday ahead of the next cold front. This second
front of the week will be stronger...traveling across the waters
Saturday morning and quickly raising SCEC flags for Saturday
afternoon 15 to 20 knot northerlies over average 5 to 6 foot seas.


College Station (CLL)      60  78  59  77  61 /  10  10  10  10  10
Houston (IAH)              60  78  58  77  60 /  10  10  10  10  10
Galveston (GLS)            66  74  65  74  67 /  10  10  10  10  10




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