Winter Storm Watch 1, NWS Corpus Christi, TX

Area Forecast Discussion
National Weather Service Corpus Christi TX
1124 AM CST Fri Feb 12 2021

.AVIATION...

IFR conditions prevail across S TX this morning. The light rain
and patchy fog will continue to dissipate over the next couple of
hours with MVFR conditions expected by mid afternoon. MVFR
conditions will persist through tonight and Saturday morning. A
slight chance of rain will continue across the coastal areas
through tonight, but am not expecting any significant aviation
impacts. Rain chances increase once again Saturday across S TX and
could see both CIGs and VSBYs at MVFR levels. Have included a
PROB30 group for all TAF sites for this potential. Gusty north
winds through early this afternoon, will decrease by late this
afternoon, becoming light to moderate.

&&

.PREV DISCUSSION... /Issued 627 AM CST Fri Feb 12 2021/

AVIATION...

Poor aviation conditions continue across area terminals this
morning with cigs/vsbys in the IFR/LIFR category. Conditions
should improve slightly throughout the day today, with most sites
lifting to MVFR levels by the afternoon. Patchy light
drizzle/rain can be expected across the eastern sites through mid
morning, with showers possible later in the morning and through
the afternoon. Drier conditions should arrive by the evening
ending the rainfall potential. Gusty northerly winds 20-25 kts this
morning are expected to subside in the afternoon, becoming light
to moderate overnight.

PREV DISCUSSION... /Issued 423 AM CST Fri Feb 12 2021/

SHORT TERM (Today through Saturday)...

Showers diminished in coverage overnight due to the arrival of
slightly drier air from the north and brief isentropic downglide.
Currently however, weak isentropic lift has resumed allowing for
foggy conditions and patchy light rain/drizzle to return to the
region, mainly across the eastern half of the CWA. Showers are
expected to develop once again through the day today as a weak
mid-level shortwave through approaches the area from the west.
This activity may also spark a few thunderstorms over the region,
but expecting the heavier showers/storms to remain over the
coastal waters where better moisture/instability should reside.
The shortwave should push east of the area tonight, surface high
pressure will then settle in filtering drier air southward and
limiting the rainfall potential. By Saturday though, rain chances
are expected to gradually increase as another mid-level trough/low
deepens over northern Mexico and approaches South Texas towards
the end of the period.

Although not anticipating measuring rainfall until after day-
break today, some Hi-Res models are indicating spotty light
precip to develop near or just north of the Victoria Crossroads
region early this morning. Some of these models' thermal profiles
are hinting the possibility of light freezing precip to occur
over this area. However, confidence on occurrence is low, so have
opted for leaving this out of the grids for now, but will
continue to monitor the situation in case an update is needed.
These conditions may exist again tonight around the same area, but
will hold-off for now as well.

Temperatures wise, expect the temperatures to remain on the
cooler side and nearly steady through the period as CAA
continues. Highs today and Saturday are forecast to stay in the
upper 30s to mid 40s, with overnight lows tonight in the mid to
upper 30s. Cloudy to mostly cloudy skies and a light to moderate
northerly breeze will continue, which will allow for wind chill
temperatures to deep into the low to mid 20s at times through the
period.

LONG TERM (Saturday Night through Thursday)...

Light rain will be possible Saturday night ahead of an approaching
mid-level trough. As the trough moves over the area, arctic air will
surge south bringing much colder temperatures to the area. As the
cold air moves into the area Sunday morning, there is a slight
chance any lingering showers could result in freezing rain or rain
mixed with sleet.

A coastal trough will increase moisture across the area Sunday night
into Monday as more cold air surges south. Rain chances will
increase as temperatures plummet. Rain will begin to transition into
freezing rain by Sunday night through Monday morning from the north
and west toward the coast. Freezing temperatures are expected along
the coast by Monday morning. Sleet may begin to mix in by Monday
afternoon for most of the area. Temperatures will remain cold
Monday, with high temperatures in the mid 30s for most of the area.
Temperatures will be extremely cold Monday night into Tuesday
morning, with lows in the lower 20s and teens as the coastal trough
shifts to the northeast, cutting of moisture advection and clearing
skies. A Freeze Warning will probably be necessary. Wind chills will
be dangerously low Sunday night through Tuesday night as strong
winds develop with each surge of high pressure. A Wind Chill
Advisory will very likely be necessary, with a warning possible
across the northern tier of counties where wind chills could drop
into the single digits.

A quick rebound to temperatures in the 40s is expected for Tuesday,
with lows still in the 30s for Tuesday night. Another coastal trough
will develop Tuesday night/Wednesday, returning moisture and the
chances for rain. Winds will increase again, once again dropping
temperatures to near freezing for Wednesday night which could lead
to some isolated spots with freezing rain. The good news is that
this should be over quickly as temperatures increase and rain
chances end Thursday.

MARINE...

Scattered showers and isolated thunderstorms will by possible
today. Moderate to strong winds will continue through Saturday. A
Small Craft Advisory is in effect across the Gulf waters through
midnight tonight, and for the bays through noon today. Isolated
showers will remain possible tonight, becoming more scattered on
Saturday. Northerly winds will continue to be strong through early next week
due to surges of arctic air. Gusts to gale force are possible Monday
and Monday Night so a Gale Warning may be necessary. Showers will be
possible over the weekend, with the chance of some wintry
precipitation mixed in Monday. Rain chances should taper off by
Tuesday but return Tuesday Night.

&&

.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi    41  37  44  35  47  /  30  20  30  30  20
Victoria          40  36  42  34  45  /  20  20  30  30  20
Laredo            43  37  41  36  43  /  20  20  40  20  10
Alice             41  36  43  34  45  /  20  20  40  30  20
Rockport          43  37  46  36  47  /  30  20  40  40  20
Cotulla           42  36  40  34  42  /  10  20  50  20  10
Kingsville        42  38  43  34  46  /  30  20  40  30  20
Navy Corpus       43  39  47  39  49  /  40  20  40  40  20

&&

.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory until midnight CST tonight For the
     following zones: 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.

     Small Craft Advisory until noon CST today For the following
     zones: Bays and Waterways from Baffin Bay to Port Aransas...
     Bays and Waterways from Port Aransas to Port O'Connor.

&&

TE/81...AVIATION

Hazardous Weather Outlook
National Weather Service Corpus Christi TX
630 AM CST Fri Feb 12 2021

TXZ229>234-239>247-342>347-442-443-447-131230-
La Salle-McMullen-Live Oak-Bee-Goliad-Victoria-Webb-Duval-
Jim Wells-Inland Kleberg-Inland Nueces-Inland San Patricio-
Coastal Aransas-Inland Refugio-Inland Calhoun-Coastal Kleberg-
Coastal Nueces-Coastal San Patricio-Aransas Islands-
Coastal Refugio-Coastal Calhoun-Kleberg Islands-Nueces Islands-
Calhoun Islands-
630 AM CST Fri Feb 12 2021

This hazardous weather outlook is for South Texas.

.DAY ONE...Today and Tonight

A Wind Chill Advisory is in effect through 9 AM for portions of
South Texas.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Freezing temperatures are possible nightly Sunday night through
Tuesday night for most locations. A Freeze Warning may be
necessary.

Wind Chill Advisory conditions are possible during the mentioned
time frame of freezing temperatures.

Sleet and light freezing rain are possible late Sunday night into
Monday.

GMZ230-235-250-255-270-275-131230-
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-
630 AM CST Fri Feb 12 2021

This hazardous weather outlook is for the Middle Texas
Coastal Waters.

.DAY ONE...Today and Tonight

Foggy conditions with reduced visibilities to 1-3 miles or less
will be possible today.

A Small Craft Advisory is now in effect through tonight with
strong northerly flow.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

A Small Craft Advisory will remain in effect for the near and
offshore waters through Friday night. Advisory conditions may
continue through the middle of the week. Gale conditions may
occur on Monday.