Area Forecast Discussion
Issued by NWS Corpus Christi, TX

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FXUS64 KCRP 200551
AFDCRP

Area Forecast Discussion
National Weather Service Corpus Christi TX
1251 AM CDT Thu Sep 20 2018

.DISCUSSION...

See .AVIATION discussion for 06Z TAFs.

&&

.AVIATION...

Isolated showers and thunderstorms already on radar and stratiform
rain over the Rio Grande moving ENE. Could have some of the
stratiform get into KLRD early, but expect it not to impact
eastern terminals at this time. Since there could be some
convection impacting KCRP terminal before sunrise, did include
VCSH (thunder still isolated and short-lived) but will monitor and
add SHRA/TSRA if needed based on radar trends. Otherwise, will
have either TEMPO TSRA and/or PROB30 TSRA in the terminals today
after sunrise as upper support and plentiful moisture will work
with daytime heating and weak sea-breeze. Will have convection end
from east to west this evening. Generally southeast winds today
not too strong. Concerning fog, clean IR satellite is showing a
lot of mid and high clouds and given that boundary layer winds are
more elevated tonight, will not hit the fog very hard at all
(more like a wait for it to develop method as think fog will be
hard to come by because of clouds). That is all.

&&

.PREVIOUS DISCUSSION... /Issued 707 PM CDT Wed Sep 19 2018/

DISCUSSION...

A quick grid update for the evening hours as multiple showers and
storms have developed across parts of the Brush Country and Rio
Grande Plains. Some of the storms have been had frequent lightning
and very heavy rainfall but we have not seen or heard of any
impacts. MSAS shows a large area of stronger moisture flux
convergence with good theta-e ridging. This boundary/convergence
will slowly wane through the evening hours as it moves towards the
west-northwest, so we cater the PoPs this evening to account for
the additional isolated/scattered activity.

00Z aviation cycle is below.

AVIATION...

Tonight...VFR/MVFR. Expecting to see some inland fog develop
tonight across the Coastal Plains, though less confident at KALI
as the surface winds may be too strong and keeps the mixing going.
IFR VSBYS are possible tomorrow morning at KVCT. Pockets of
stratus are also possible across much of the region developing
late tonight and moving inland during the morning hours. Medium
confidence.

Thursday...Mostly VFR. Gulf moisture starts to ramp up back into
the region and we expect the sea breeze and other upper level
disturbances to touch off widely scattered showers and
thunderstorms. We continue with the PROB30s for the time being as
the time of any impacts to our terminals is still a bit
questionable. Medium confidence.

PREVIOUS DISCUSSION... /Issued 332 PM CDT Wed Sep 19 2018/

SHORT TERM (Tonight through Thursday night)...

GOES total precipitable water image continues to show the deeper
moisture axis from off the lower Texas coast northwest into the
southern portions of the Coastal Bend and Brush Country. Water
vapor imagery indicates a weak upper low near San Antonio with
weakly divergent flow aloft to the south of the upper low over
south Texas. Isolated convection between Alice and Falfurrias
will move northwest into the Brush Country this evening.

Water vapor imagery also depicts a short wave trough from the
Texas Big Bend into Coahuila this afternoon. This feature will
move northeast tonight and be over the Brush Country by 12Z
Thursday. Will keep a slight chance of convection over the Brush
Country overnight. There will also be a slight chance of showers
developing along the coast as higher moisture steadily moves
into the region from the Gulf. Will show the best chances for rain
across the Brush Country to the Victoria Crossroads Thursday into
Thursday night as the weak short wave trough moves to the
northeast on Thursday and another impulse moves into the region
from Coahuila Thursday night.

LONG TERM (Friday through Wednesday)...

More rainy, unsettled weather is in store for South Texas through
the weekend and into early next week.  The upper level ridge will be
east of the region on Friday, with a shortwave trough sweeping into
the Central and Southern Plains.  Both the GFS and ECMWF indicate
deep moisture will again spread across the region, with precipitable
water values near 2.2 to 2.4 inches Friday and over the weekend.
This trough axis will very slowly move over the state, with a front
stalled across Texas, north of the region. Scattered to numerous
showers and storms are expected to develop on Friday and Saturday.
Additional moderate rainfall amounts may develop with training
storms, but have held off mention for the time.  The shortwave axis
shifts further east early next week, with the frontal boundary
ebbing slightly closer to the region before washing out.  Chances
for showers and storms will continue on Sunday, with decreasing
coverage on Monday. However, the high moisture axis does remain over
the region, and as a longwave trough begins sliding into the central
CONUS during the middle of next week additional isolated to
scattered showers and storms will be possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi    78  87  77  86  76  /  20  50  50  50  40
Victoria          76  88  75  86  74  /  30  60  50  60  40
Laredo            77  91  76  89  75  /  30  40  50  60  50
Alice             77  89  76  88  74  /  30  40  50  50  50
Rockport          80  88  78  88  77  /  20  50  50  60  40
Cotulla           75  88  75  87  73  /  50  50  60  60  50
Kingsville        77  89  77  88  76  /  30  40  40  50  50
Navy Corpus       81  88  79  88  78  /  20  50  50  60  40

&&

.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.

&&

$$

GW/86...AVIATION


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