Area Forecast Discussion
Issued by NWS Corpus Christi, TX

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FXUS64 KCRP 281513

Area Forecast Discussion
National Weather Service Corpus Christi TX
1013 AM CDT Fri Jul 28 2017


A pool of deeper moisture over the coastal waters will be hindered
from developing into convection due to high pressure aloft. A few
light and very brief showers are possible but not enough to
warrant mentioning in the zones or coastals. The 12Z CRP sounding
also showed a strong capping inversion with very warm lower to mid
levels. This will lead to very hot conditions this afternoon. The
dewpoints are expected to mix out and decrease, thus heat indices
should remain below 110 degrees. Overall, forecast looks on track
with no major changes at this time.


.PREVIOUS DISCUSSION... /Issued 631 AM CDT Fri Jul 28 2017/

DISCUSSION...Update for 12z Aviation.

AVIATION...VFR to prevail for fast majority of TAF period. Brief
IFR/MVFR VSBYs possible at KALI very early in the TAF period but
should rapidly transition back to VFR. Areas of MVFR CIGs
currently exist across portions of the region...but all in all
cloud cover should not be much of a wx impact today. By mid mrng,
a thin Cu field should start to dvlp with CIGs quickly rising
this mrng...and cloud cover dsptng this afternoon as drier air
aloft overspreads the area. Weak SSwrly sfc winds this mrng becmg
SErly 15 to 20 kts by late aftn/evening as the seabreeze pushes
inland. Weakening wind fields overnight with mainly clear skies

PREVIOUS DISCUSSION... /Issued 332 AM CDT Fri Jul 28 2017/

SHORT TERM (Today through Saturday)...

Greater deep layer moisture is currently located along/offshore
of the Mid TX Coast (per GOES 16 derived imagery). However, this
deeper moisture is prog to diminish through the day as strong
diurnal warming and corresponding mixing occurs. Surface and H85
pressure centers, currently located over the NW Gulf, are prog to
slowly shift south and west today. Result will be even further
drying of of the atmosphere and an increase in subsidence...and in
increase in temps. H85 temps are prog to warm to around 22C this
afternoon across the coastal counties and to around 25C along the
Rio Grande. These values are about two standard deviations above
normal for this time of year...and are prog to increase further
for Saturday afternoon. Result will be hot temperatures areawide
for today and Saturday (with Saturday being the hottest of the two
days). Despite the increase in air temps, lower dewpoints are
expected to occur each afternoon due to an increase in subsidence
and an area of drier air over the gulf that is prog to wrap into
the area. This should help limit widespread dangerous heat indices
late this week (although hot sfc temps will still
Mostly sunny skies each day due to decreasing moisture depth. Weak
surface winds in the morning becoming breezy/gusty from the
southeast each afternoon/evening as the seabreeze pushes inland.

LONG TERM (Saturday night through Friday)...

Moisture begins to increase from NE-SW Saturday night. GFS is
showing PWATS nearly 2.5 inches just offshore Sunday, while other
models keep the best moisture farther north and/or east. In either
case, there seems to be enough moisture over the eastern areas to
put in at least a low chance for showers/storms on Sunday, and will
mention convection all but the Rio Grande Plains area. Models push
the better moisture farther south and east Sunday night and Monday,
as the upper ridge becomes more N-S oriented. Thus, expect rainfall
to be more limited Monday and Tuesday. For now, will maintain a 20
POP southern areas then keep things dry for Tuesday. The upper ridge
becomes even more N-S oriented Wednesday, with a few weak
disturbances possible in the northerly flow. There could even be a
weak frontal boundary near the area Wednesday or Thursday, and the
converging winds proximate to the boundary and the northerly flow
aloft provides the potential for showers and thunderstorms either to
develop over the area, or develop farther north (where good moisture
initially is), and move southward in the northerly flow. Best
chances for convection appear to be Wednesday and Thursday as the
moisture available is best and there are hints of a disturbance or
two in the northerly flow. Thus, will go with at least a mention of
precipitation these days.

Concerning temperatures, looks like it will start off very warm (or
hot) on Sunday, then temperatures will gradually diminish as more
clouds and moisture move into the area. Going a bit cool (for this
time of year) Wednesday and Thursday as expect plenty of clouds and
rain-cooled areas, along with the potential for cooler air not
necessarily from Canada but from the colder air generated by the
thunderstorms. Thus, by Thursday temperatures will be near if not
slightly below normal. Generally used a blend of Superblend and Bias-
corrected raw model forecast grids, with modifications near the
coast as needed.


Corpus Christi    97  75 100  75  99  /   0   0   0  10  20
Victoria         100  76 102  76  99  /  10  10  10  20  40
Laredo           105  79 107  77 106  /   0   0   0  10  10
Alice            101  74 104  73 102  /   0   0   0  10  20
Rockport          94  80  95  79  94  /  10  10  10  10  30
Cotulla          104  77 106  76 106  /   0   0   0  10  20
Kingsville       101  76 102  74 102  /   0   0   0  10  20
Navy Corpus       94  81  95  80  96  /  10  10  10  10  20





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