Severe Thunderstorm Warning 49, NWS Corpus Christi, TX

Area Forecast Discussion
National Weather Service Corpus Christi TX
645 PM CDT Sun May 24 2020

.AVIATION /00Z TAFs/...
The main aviation concern for the 00Z TAFs centers around timing
of TSRA at all terminals tonight.

Area radars shows thunderstorms rapidly developing along the Rio
Grande this evening with a secondary area of development along
Interstate 10 in between SAT and HOU as a shortwave trough lifts
out of northern Mexico. TSRA along the Rio Grande are expected to
grow upscale into a larger complex through the evening hours,
reaching LRD and COT by 04Z. Increasing forcing from the
aforementioned trough has already resulted in smaller TSRA
development near COT and terminal impacts are expected to occur
shortly. TSRA will be capable of straight-line winds in addition
to large hail and IFR or LIFR visibilities from locally heavy
rain. Expect the TSRA cluster to propagate from west to east
towards ALI and CRP after 06Z with improving conditions at these
terminals behind TSRA passage.

The secondary cluster of TSRA noted along Interstate 10 may
propagate towards the south through the evening hours as outflow
has begun to surge southward and VCT may see an initial round of
TSRA activity before the Rio Grande storms arrive before 12Z.
Overnight rainfall and a weakness in the wind field may result in
temporary MVFR ceilings and visibilities developing before mixing
out mid-morning. SHRA may redevelop near COT/LRD closer to 17Z
from diurnal heating with VFR conditions and southeast winds 10-15
knots with gusts 20-25 knots throughout the afternoon. Another
TSRA cluster may approach the South Texas terminals after 00Z
Tuesday.

&&

.PREV DISCUSSION... /Issued 409 PM CDT Sun May 24 2020/

SHORT TERM (Tonight through Monday night)...

An upper level disturbance is expected to approach the CWA
tonight and combine with high CAPE (2500-3500 J/kg per NAM
deterministic), above normal PWAT values, and significant 0-6km
vertical shear, to generate strong to possibly severe convection
tonight. Concur with SPC with respect to a Slight Risk overnight.
HREF output suggest convection could occur between 00z and 12z
Monday. Anticipate an MCS to move across the region and thus will
likely move across the CWA in 1/2 the time, yet unsure of the
specific timing. Monday, anticipate isolated/scattered convection
during the afternoon. Monday night, deterministic output predicts
another yet stronger upper disturbance to enter the CWA after 00z
Tuesday. Expect another period of scattered to numerous showers
over the CWA. Water levels may reach the threshold for coastal
flooding during the next high tide. However, convection
overnight/early Monday may disrupt necessary wind forcing. The
PETSS suggests that maximum water levels may occur just below the
threshold. Nevertheless, will defer to later shifts to decide on
possible CFW issuance.

LONG TERM (Tuesday through Sunday)...

Remaining quite active at the beginning of the extended period
Tuesday morning as a closed low develops over north Texas and a weak
frontal boundary slides across the region. Moisture convergence
along this boundary, steep lapse rates and moderate instability are
all expected to contribute to the formation of an MCS northwest of
the area late Monday night that will push across South Texas Tuesday
morning. Given these factors, along with a weak cap in place,
scattered to numerous showers and thunderstorms will remain likely
through early Tuesday afternoon, with some of the storms becoming
strong to severe at times. Therefore, both SPC and WPC have
maintained the region under a Marginal Risk for severe weather and
excessive rainfall respectively mainly for the aforementioned time
frame. The convective line is forecast to move offshore by Tuesday
afternoon, and drier air will filter in from the north as a surface
high pressure builds over central Texas. Mostly dry conditions can
be expected Tuesday night through possibly Wednesday night, but
slight to chance PoPs will remain in the forecast through next
weekend as the closed low meanders across the state sending a few
weak impulses into the region which will combine with the available
moisture and instability to produce some showers/storms. Otherwise,
mostly cloudy skies and below to near normal high temperatures will
continue through Sunday next week.

MARINE...

Scattered/numerous showers and thunderstorms overnight/Monday.
In response to a strong upper level disturbance,
scattered/numerous showers and thunderstorms expected again Monday
night. A weak to moderate onshore flow will persist through
midweek with daily chances for thunderstorms. Winds may briefly
turn northeast Tuesday afternoon behind a weak frontal boundary,
before weak offshore winds arrive on Wednesday. Scattered to
numerous thunderstorms, some severe, will be possible Tuesday.
Isolated to scattered showers will continue through the week and
into the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi    74  87  71  83  69  /  60  50  60  70  30
Victoria          71  86  69  83  67  /  70  60  60  70  30
Laredo            72  90  71  86  69  /  70  20  60  50  20
Alice             71  90  70  85  67  /  70  40  70  70  30
Rockport          76  87  73  84  72  /  70  60  60  70  40
Cotulla           69  90  68  86  67  /  70  30  70  50  20
Kingsville        72  90  71  85  68  /  60  40  60  70  30
Navy Corpus       76  85  73  83  73  /  60  60  60  70  40

&&

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

&&

MSH/98...AVIATION

Hazardous Weather Outlook
National Weather Service Corpus Christi TX
352 AM CDT Sun May 24 2020

TXZ229>234-239>247-342>347-442-443-447-250900-
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-
352 AM CDT Sun May 24 2020

This hazardous weather outlook is for South Texas.

.DAY ONE...Today and Tonight

Isolated to scattered thunderstorms today will become more
numerous tonight. Some severe wind gusts and hail are possible
tonight in addition to heavy rainfall and minor flooding.

.DAYS TWO THROUGH SEVEN...Memorial Day through Saturday

Scattered to numerous thunderstorms are possible again on Monday
night with heavy rainfall the greatest threat. The risk for
flooding will continue through the week as additional rounds of
storms develop at times.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed tonight. Please relay any
information about observed severe weather to the NWS while
following all local, state and CDC guidelines.

GMZ230-235-250-255-270-275-250900-
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-
352 AM CDT Sun May 24 2020

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

.DAY ONE...Today and Tonight

Isolated to scattered thunderstorms will occur at times. A few
strong storms are possible.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Scattered to numerous thunderstorms are likely early Memorial Day
morning and again Tuesday morning, before becoming isolated to
scattered through the rest of the week. Some storms Memorial Day
and Tuesday may be strong to severe with gusty winds and hail.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Special Weather Statement
National Weather Service Corpus Christi TX
726 PM CDT Sun May 24 2020

TXZ229-239-250115-
Webb-La Salle-
726 PM CDT Sun May 24 2020

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTH CENTRAL WEBB AND
WESTERN LA SALLE COUNTIES...

At 726 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Catarina to La Esperanza Ranch
Airport. Movement was northeast at 15 mph.

Winds in excess of 40 mph and pea size hail are possible with these
storms.

Locations impacted include...
Cotulla, Encinal, Artesia Wells, Woodward, La Esperanza Ranch Airport
and Chaparral Wildlife Management Area.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 2820 9969 2820 9940 2864 9940 2839 9909
      2806 9919 2796 9958 2817 9971
TIME...MOT...LOC 0026Z 220DEG 15KT 2836 9954 2808 9954

Huffman

Special Weather Statement
National Weather Service Corpus Christi TX
734 PM CDT Sun May 24 2020

TXZ239-250115-
Webb-
734 PM CDT Sun May 24 2020

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN WEBB COUNTY...

At 734 PM CDT, a strong thunderstorm was located 17 miles west of
Columbia Bridge, or 36 miles northwest of Laredo, moving north at 25
mph.

Wind gusts of 50 to 55 mph are possible with this storm and will
likely be felt well ahead of the thunderstorm.

Locations impacted include...
Las Tiendas and Chupadera Ranch Airport.

To report severe weather, contact your nearest law enforcement
agency. They can relay your report to the National Weather Service
office in Corpus Christi.

LAT...LON 2820 9973 2781 9947 2773 9979 2778 9982
      2776 9984 2779 9985 2780 9988 2784 9988
      2788 9991 2791 9990 2794 9994 2798 9993
      2800 9999 2807 10002 2809 10005 2815 10009
      2817 10016 2820 10021
TIME...MOT...LOC 0034Z 196DEG 20KT 2781 10000

Huffman