Area Forecast Discussion


307 
FXUS64 KCRP 180447
AFDCRP
Area Forecast Discussion
National Weather Service Corpus Christi TX
1047 PM CST Sat Nov 17 2018
.DISCUSSION...
Updated for 06Z aviation discussion.
&&
.AVIATION...
Seeing a gradual lowering of CIGS so far this evening, but most
sites still in the VFR category. Over the next few hours will see
all sites fall to MVFR and potentially IFR toward morning as a
cold front approaches. MVFR visbys will be possible overnight as
well with the continued increase in low level moisture. Rain 
chances will also gradually increase through the night. The cold 
front will move through the TAF sites from north to south from 
late morning into the early afternoon. Gusty northerly winds will 
develop and last through the end of the period. CIGS will be 
expected to remain MVFR behind the front as well. 
&&
.PREVIOUS DISCUSSION... /Issued 419 PM CST Sat Nov 17 2018/ 
SHORT TERM (Tonight through Sunday Night)...
Tonight moisture will continue to increase across the region with
a moderate onshore flow. A few light showers and sprinkles have
already begun developing across the Coastal Bend and Coastal
Plains late this afternoon. Isentropic upglide will produce 
scattered showers overnight, with coverage increasing across the
Coastal Bend into the Victoria Crossroads after midnight. 
Additionally, patchy fog to areas of fog may develop late tonight
into early tomorrow morning. By early Sunday morning a cold front
will be positioned across the Hill Country. A cold front is still
expected to push south and through the region during the day 
tomorrow. Confidence is not too high on the exact timing of the 
fropa, as the NAM continues to surge the front more quickly 
through the region and the coastal waters, while the GFS and ECMWF
bring the front through more gradually throughout the day. Leaned
towards a slightly slower solution, though still have the front 
moving through the northern counties by 18z and to the coast by 
around 00z. Anticipate the front to then stall over the coastal 
waters, with a coastal trough then developing late Sunday night 
into early Monday morning. Scattered to numerous showers will 
develop over the region tomorrow morning, with the highest 
coverage over the coastal waters and coastal bend. A few 
thunderstorms may develop over these areas, but the majority of 
the activity should be showers. Overrunning showers will persist 
through the afternoon and into tomorrow night with the boundary 
positioned over the coastal waters. Temperatures on Sunday are a 
bit tricky, with highs being entirely dependent on timing of the 
frontal passage. Anticipate highs will be reached closer to noon 
in the mid/upper 60s across the northern CWA, and in the low 70s 
to the south and along the coast, with temps falling through the
afternoon. If the solution were closer to the swift timing of the
NAM though, the high temperatures across the south and coast 
could be a bust. Lows tonight will be in the lower 60s, with
tomorrow night cooler in the upper 40s to mid 50s.
LONG TERM (Monday through Saturday)...
Concur with the deterministic GFS/ECMWF which predicts a coastal 
trough to develop Monday, likely in part due to a weak upper 
disturbance (identified with 700-300mb Q-vector convergence.) 
Anticipate at least scattered convection in response. Tuesday, 
concur with the GFS/ECMWF with respect to the movement of the 
surface trough offshore (yet ECMWF slower with this movement.) For 
Tuesday night/Wednesday, in response to another yet stronger upper 
disturbance, the coastal trough redevelops. The combination of the 
upper/surface forcing likely to generate scattered convection by 
Wednesday. Thursday, the upper disturbance moves east of the region 
(GFS/ECMWF/GFS ensemble mean) resulting in drier conditions. 
Although the GFS predicts PWAT values to be above normal 
Friday/Saturday, high condensation pressure deficits are predicted 
to remain over the CWA, and do not anticipate significant 
precipitation.
MARINE...
Onshore flow will persist overnight with a chance for showers. A
cold front will move into the waters overnight and stall.
Scattered to numerous showers will be possible Sunday and Sunday
night. A coastal trough develops Monday and contributes 
convection, moves offshore Tuesday in response to the upper 
pattern, resulting in a decreasing chance for convection and SCEC 
wind, then moves back to the coast Wednesday in response to an 
upper level disturbance and thus increasing the chance for 
convection. Drier Thursday as the upper system moves east. 
Isentropic lift/weak condensation pressure deficits may contribute
to isolated showers/patchy light rain Thursday/Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi    64  73  53  59  52  /  50  70  60  60  50 
Victoria          60  68  48  55  47  /  50  70  60  60  40 
Laredo            61  70  51  57  49  /  20  40  50  40  20 
Alice             62  71  51  57  49  /  40  70  50  50  40 
Rockport          65  71  52  59  52  /  50  70  60  70  50 
Cotulla           60  65  49  57  47  /  30  40  40  40  20 
Kingsville        63  74  53  59  51  /  40  70  60  60  40 
Navy Corpus       68  74  56  62  55  /  50  70  60  60  50 
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
PH/83...AVIATION