Area Forecast Discussion
Issued by NWS Corpus Christi, TX

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FXUS64 KCRP 291721
AFDCRP

Area Forecast Discussion
National Weather Service Corpus Christi TX
1221 PM CDT Wed Mar 29 2017

.DISCUSSION...

See aviation discussion below for the 18Z TAF`s.

&&

.AVIATION...

VFR conditions across S TX will continue through the TAF period. A
boundary and associated convection has moved offshore this
afternoon with drier conditions filtering into S TX through the
afternoon. Skies are expected to become mostly clear across the
area this afternoon with a few mid/upper level clouds overnight
developing in response to an upper level low treking east. Sfc
winds will generally be light and variable through the early
afternoon then becoming more easterly by mid/late afternoon for
ALI, CRP and VCT as the sea breeze moves inland. A weak cold front
is expected to move through S TX late tonight and into early Thu
morning resulting in a weak to moderate NW to N wind in the
morning.

&&

.PREVIOUS DISCUSSION... /Issued 955 AM CDT Wed Mar 29 2017/

DISCUSSION...

The 12Z CRP sounding showed a very unstable airmass, but a capping
inversion around 700mb has kept the convection generally low
topped, except around VCT where the cap is weaker. The convection
that is currently draped along the coast, is expected to continue
to move E and NE across the coastal waters and exit the area over
the next couple of hours. A dryline bdry along the coast is
expected to stall along the coast or over the near shore waters
then retreat inland as a sea breeze this afternoon. West of the
bdry, dry conditions along with a W to NW wind will lead to very
warm temps today, however, temps will be tricky along the coastal
counties due to uncertainty in timing of the sea breeze. Overall,
the forecast looks on track with no major changes expected other
than to lower/remove pops once the convection has exited the area.

PREVIOUS DISCUSSION... /Issued 617 AM CDT Wed Mar 29 2017/

DISCUSSION...Update for 12z Aviation.

AVIATION...Main wx impact this mrng to be from possible
convection. Convection has been struggling to dvlp overnight but
is finally getting its act together more and is likely to impact
KVCT shortly after the start of the TAF period thru mid mrng.
Brief reductions in VSBYs and CIGs possible along with isolated
strong wind gusts. Lower certainty exists as to whether or not
convection will reach/impact KCRP. Potential exists for convection
to dvlp/strengthen vcnty KCRP...but impacts should be brief if
they occur. KALI likely to only experience brief light/moderate
SHRA with KLRD remaining dry. MVFR CIGs possible thru mid mrng
with mainly clear skies thereafter as significantly drier airmass
overspreads the region. Generally weak sfc winds today 5 to 10 kts
on avg.

PREVIOUS DISCUSSION... /Issued 444 AM CDT Wed Mar 29 2017/

SHORT TERM (Today through Thursday)...

The leading edge of a surface boundary /and also a gravity wave as
noted from GOES-R satellite imagery/ was analyzed to be located from
KBEA to just west of KALI to NW of KHBV to south of KLRD as of
writing. Behind the boundary, elevated convection has been trying
to develop but is struggling to maintain itself due to limited
moisture depth. Better convective development may occur closer to
sunrise across the Coastal Plains to Victoria where the moisture
depth is prog to be deeper, where instability is prog to be
greater, and where H25 difluence is prog to be a little better.
Any storms that manage to develop this morning will have the
potential to produce small hail /given the extreme elevated
instability values/ and perhaps an isolated strong wind gust.
Precip chances should quickly end by mid morning as a
significantly drier airmass overspreads most of inland S TX as the
aforementioned boundary stalls along the coast.

Temps today are likely to warm into the 90s in the afternoon given
the expected dry airmass and a weak adiabatic downsloping
component. I am a little concerned that I did not go warm enough
for the coastal counties as this synoptic setup can often lead to
incredible warming across the Coastal Plains. However, given the
expected strong inland warming and quasi-cool Gulf SSTs, the
stalled boundary should start to retreat inland in the afternoon
acting as an effective seabreeze. Thus...I have limited Corpus
Christi`s max temp today to only 92 degrees rather than the mid
90s.

Near surface moisture values are likely to increase this evening
ahead of the main cold front that is prog to push south across the
region late tonight. The GFS wants to develop light showers
across the Coastal Plains/adjacent Gulf right along/ahead of
FROPA late tonight. Despite impressive dynamical features aloft
/95 to 100 kt H25 jet streak and deep H5 trough/ moisture depth
limited to only the lowest 100mb as well as a thin layer around
H5 should preclude any precip development.

NNW winds should increase late tonight with breezy conditions
possible around sunrise Thurs. Mostly sunny skies with low
relative humidity values and temps near seasonable levels should
make for a nice day on Thursday.

LONG TERM (Thursday Night through Tuesday)...

The deterministic solutions generally agree with regard to the
timing/position of the next upper disturbance...moving SEWD across
the Rockies Friday then slowly approaching TX from the NW
Saturday...moving across TX Sunday/Sunday Night...then lifting NEWD.
Increasing onshore flow expected over the CWA/MSA given the
foregoing upper pattern. At least SCEC conditions expected over the
Coastal MSA Friday Night through early Sunday. GFS deterministic
predict PWAT values to increase to near/above normal values Saturday
over the ERN CWA/MSA. The combination of upper forcing/moisture will
contribute to at least isolated/scattered convection Saturday
Night/Sunday. Strong convection possible given GFS deterministic
CAPE/vertical shear. Drier conditions expected Monday/Tuesday.

MARINE...Strong southeast flow should rapidly weaken this
morning. Seas, however, may be slow to respond and the Small Craft
Advisory has been extended through much of today for the Gulf
waters to account for the hazardous seas. A brief window for
chances of showers or a storm will exist this morning and early
afternoon. A cold front will push south across area waters late
tonight into Thursday morning bringing a brief period of strong
north flow in its wake.

&&

.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi    92  61  82  58  86  /  40  10  10   0   0
Victoria          88  57  79  55  85  /  50  10  10   0   0
Laredo            92  61  86  60  97  /   0   0   0   0   0
Alice             94  58  84  56  90  /  20  10   0   0   0
Rockport          86  60  79  61  80  /  40  10  10   0   0
Cotulla           91  56  84  56  94  /   0   0   0   0   0
Kingsville        96  59  84  57  90  /  20  10   0   0   0
Navy Corpus       88  63  79  63  81  /  40  10  10   0   0

&&

.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory until 4 PM CDT this afternoon For the
     following zones: 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.

&&

$$

TE/81...AVIATION



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