Area Forecast Discussion
Issued by NWS Corpus Christi, TX
FXUS64 KCRP 201155 AAA
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
555 AM CST Fri Jan 20 2017
See Aviation discussion for 12Z TAFs.
The first couple hours of the visibility forecast is based on the
latest observations in part because guidance has been poor and
visibilities have been fluctuating quite a bit, going from 1/4SM
to more than 3SM in some locations. Am expecting visibilities to
bottom out by TAF starting time with fluctuation of visibilities
continuing but improving conditions by 16Z. LIFR conditions
(either due to CIGs or VSBYs) will only slightly improve this
morning, as winds are light and model sounding/time heights
showing low clouds hanging around. Am expecting VFR conditions to
develop at KLRD around 18Z and KALI/KCRP 21Z or 22Z, with no
better than MVFR conditions at KVCT today. Upper trough will
provide for some showers, but for now have just gone with VCSH at
KCRP and KVCT as do not expect a lot of precipitation (thunder too
isolated to put in TAF). Conditions are expected to deteriorate
rapidly tonight (except at KLRD), with LIFR conditions developing
AOA 21/06Z as light winds and less cloud cover aloft will bring
restrictive CIGs and/or VSBYs. See terminal forecasts for details.
.PREVIOUS DISCUSSION... /Issued 308 AM CST Fri Jan 20 2017/
SHORT TERM (Today through Saturday)...
Main issues are fog each period (whether it will be dense enough for
an advisory and where), then rain chances today and this evening.
Have already issued a Dense Fog Advisory as expect most areas to
have low visibilities enough to warrant the advisory. Fog will
likely be an issue again tonight once the main energy from the upper
trough exits. There still could be enough clouds around to keep
widespread dense fog from forming. For now, will just go with
areas of fog.
Concerning the rain chances today and tonight, the upper trough will
provide some upward motion and there is some returning moisture
advection in the lower and mid levels. Ergo, will have chance
POPs today for the eastern-most areas as low and mid level theta-e
advection will pretty restricted to the eastern areas, and rain
may be harder to come by farther west. Thunder will be possible as
well, but more showers than thunder. Am expecting to see
temperatures near 80F out west with some decrease in clouds, but
mid 70s most coastal areas as lower clouds linger. Light winds
tonight and with a southwest component am expecting temperatures
mainly in the 50s by Saturday morning over inland areas.
Upper trough begins to exit on Saturday, and it looks to be very
warm as downslope westerly winds warm the near surface air. Am
pretty much going 80s area-wide except the immediate coast. Going
with a blend of NAM-MOS and bias-corrected NAM-MOS with a few
adjustments for Saturday. For tonight, closer to the SREF and
bias-corrected SREF (again with adjustments). A blend of guidance
for today`s temperatures.
MARINE (Today through Sunday)...
There are no marine concerns through Saturday as winds remain well
below any advisory criterion. Some scattered showers/storms today
ending around midnight. By Sunday winds crank up and the forecast
calls for 30 to 35 knots over portions of the gulfmex. As a result,
have issued a Gale Watch for Sunday. Areas where sustained winds
will not be 30 to 35 knots will likely see frequent gusts to 35
knots or more so have included them in the Gale Watch.
LONG TERM (Saturday Night through Thursday)...
Sunday is shaping up to be a very windy day in the wake of a Sat
night cold front. A Wind Advisory will likely be needed on Sunday
and a Fire Weather Watch has already been issued due to much drier
conditions, as well as a Gale Watch for marine interests.
Another deepening upper level low in a progressive pattern aloft, is
progged to move across N TX Sat night and push a cold front through
S TX. A 50KT NW Low Level Jet is progged to develop behind the front
along with a 120KT upper level jet. Given the very strong winds
through a deep layer and an environment conducive for these winds to
mix to the sfc, am expecting a very windy Sunday. Temps will be
slightly cooler but the deep subsident NW flow will counteract the
CAA. By Sun night, winds begin to diminish and temps are expected to
drop into the 40s. Dry conditions are progged to persist through Mon
as the high pressure shifts east and an onshore flow develops. The
onshore flow will strengthen and usher limited low level moisture
back across S TX and Middle TX Coastal Waters bringing a slight chc
of convection to mainly the coastal waters by Tue. The warm temps
will also return for Tue. The next cold front is then progged to
move through S TX Tue night/Wed with Small Craft Advisory conditions
possible across the waters by Wed afternoon or night as a secondary
push of high pressure moves across the region. Moisture remains
limited with only isol convection expected over the waters through
mid week. Temps will be cooler Wed with highs in the 70s then highs
in the 60s expected Thu.
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 76 58 87 52 74 / 30 10 10 10 0
Victoria 75 58 81 51 72 / 30 10 10 10 0
Laredo 80 55 82 51 75 / 10 0 0 10 0
Alice 78 57 87 51 75 / 20 10 10 10 0
Rockport 75 58 84 53 72 / 30 10 10 10 0
Cotulla 81 53 80 49 74 / 10 0 0 10 0
Kingsville 78 58 87 52 74 / 30 10 10 10 0
Navy Corpus 74 60 82 54 72 / 30 10 10 10 0
TX...Fire Weather Watch from Sunday morning through Sunday afternoon
For the following zones: Aransas...Bee...Calhoun...Duval...
Goliad...Jim Wells...Kleberg...La Salle...Live Oak...
Dense Fog Advisory until 9 AM CST this morning For the following
GM...Gale Watch from late Saturday night through Sunday evening For
the following zones: Bays and Waterways from Baffin Bay to
Port Aransas...Bays and Waterways from Port Aransas to Port
O`Connor...Coastal waters from Baffin Bay to Port Aransas
out 20 NM...Coastal waters from Port Aransas to Matagorda
Ship Channel out 20 NM...Waters from Baffin Bay to Port
Aransas from 20 to 60 NM...Waters from Port Aransas to
Matagorda Ship Channel from 20 to 60 NM.