Area Forecast Discussion
Issued by NWS Corpus Christi, TX
FXUS64 KCRP 260000 AAA
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
700 PM CDT WED MAY 25 2016
.DISCUSSION...See 00Z aviation discussion below.
.AVIATION...CIN is lessening but should be coming back by mid
evening. This may be enough to bring a strong storm to KLRD
terminal before 04Z (have in tempo). Otherwise, am expecting
storms to weaken as they move east into South Texas overnight,
with mainly elevated/nimbo-stratus type of thunder during the
evening hours/overnight. Feel somewhat confident that some thunder
will get to KALI by 06Z (nothing too strong...have tempo for
terminal), then farther east becomes more uncertain as storms move
even farther away from best lift, moisture and instability. Still
will have some tempos at KCRP and KVCT (may just be showers but
could not rule out thunder). Since rainfall is within 9 hour
timeline (no PROB30), will go with tempo thunder at both KCRP and
KVCT. Could have some remnant rains at KLRD and KALI between 08Z-
11Z (ending west to east). Chance for convection again Thursday
afternoon after 20Z...but for now will only go with VCTS.
Otherwise, am expecting MVFR conditions to develop even outside
of convection eastern terminals by 03Z and KLRD after 06Z. Will
forecast VFR after 16Z all terminals. Weakening SE winds tonight
and then South on Thursday morning becoming SE in the afternoon
with a few gusts as surface pressure gradient tightens and
approaching upper system helps increase winds.
.PREVIOUS DISCUSSION... /Issued 425 PM CDT WED MAY 25 2016/
SHORT TERM (Tonight through Thursday night)...Uncertainty still
lies in the short term forecast with regard to the exact development
of convection over the next 24 to 36 hours. Upper level low
positioned over southern CA and the Baja Peninsula will slowly
track further east over the desert southwest/Four Corners region.
Several impulses ejecting from this low will cross the region
overnight through Thursday night. Morning sounding from DRT showed
massive capping over the region, but very steep EML lapse rates.
Special 18Z sounding again from DRT showed cap still holding on
over this region. That said, capping may hold and inhibit storms.
Further west of the Rio Grande over Mexico, instability appears
greater though, and starting to see convection forming over the
mountains west of the CWA with strengthening shortwave impulse
aloft. Convection that does make push into the region would have
the potential to produce hail and strong winds with such steep
lapse rates and around 35 to 40 kts 0-6km shear. Hi-res models
continue to indicate an MCS developing over the Mexican border and
pushing east to northeast overnight across the region. There are
still some uncertainty though as to whether or not this
development will make it into South Texas and/or how much it will
weaken as it move across the region.
Overnight convection lingering into mid tomorrow morning will be possible.
However, another round of storms developing and pushing across the
CWA will be possible tomorrow afternoon and continuing into
Thursday night. Potential for strong to severe storms still exists
(SPC has placed Slight Risk to the northwest of the region, with
most of South Texas in a Marginal Risk), with the primary threats
again being hail and strong winds.
In addition to the strong to severe storms threat, potentially
heavy rainfall will be an issue. PWAT values near to slightly
above 2 inches (+2SD) are progged across the region through
Thursday into Thursday night. If training or slow moving storms
were to develop, localized flooding may become an issue,
especially across areas that have received an abundant amount of
rain already this month. QPF amounts through Friday are expected
to be 1-2 inches, with locally higher amounts of 4 inches
LONG TERM (Friday through Wednesday)...
Unsettled weather pattern for South Texas continues with continued
deep layer southerly flow in place. The stronger shortwave forecast
to move through the region on Thursday should be ejecting to our
north-northeast by early Friday morning with another shortwave right
on its tails. Highest POPs Friday are confirmed mostly to the
Northern Brush Country east into Victoria Crossroads and then taper
off gradually through Saturday. Some of the storms on Friday may
become severe in nature with ample instability and lots of dynamics
to work with. Upper level subtropical jet will place its left exit
region overhead while the polar jet to our north has us in its right
entrance region. This adds to stronger upper level lift adding to
the potential for the strong/severe thunderstorm potential. On top
of that with excessive PWATs values these storms may cause localized
flash flooding, though the best chances for this all may be just a
tad to our north.
Saturday and Sunday we should dry out some as the PWATs are forecast
to drop towards 1.5 inches, at least across the east, but we reload
and are running near 2 inches by early next week. Capping inversion
does not appear to as strong as we have seen the past several days
so any embedded impulse within the southerly flow aloft would be
enough to trigger scattered convection. We carry chance POPs through
much of the period, better west than east, to account for the lack
of capping, some cooler mid-level temperatures with troughing nearby
and several shortwaves moving through the mean flow.
Marine...Moderate to strong onshore Friday allows for SCA conditions
as seas continue to remain elevated around 6 feet nearshore and
around 8 feet farther offshore.
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 78 87 78 89 78 / 40 50 40 40 20
Victoria 76 84 75 85 74 / 30 50 40 60 40
Laredo 77 93 76 95 76 / 50 40 40 20 20
Alice 77 89 77 91 75 / 50 50 40 40 20
Rockport 79 85 78 87 79 / 30 40 40 40 20
Cotulla 76 91 75 94 73 / 50 50 50 20 20
Kingsville 78 90 78 91 77 / 40 50 40 40 20
Navy Corpus 79 85 78 87 79 / 30 40 30 40 20