Area forecast discussion
National Weather Service San Angelo Texas
1251 am CDT Tuesday Jun 18 2013
Discussion...
Look for VFR conditions to dominate west central Texas for the
next 24 hours. See aviation below for details.
&&
Aviation...
Models this cycle continue showers and thunderstorms across some
of west central Texas tonight and for much of west central Texas
again tomorrow afternoon. The NAM indicates the best chance for
thunderstorms tonight will be across our southern counties.
However...radar trends over the last couple hours indicate the
thunderstorm complex over the Concho Valley is weakening. Thus...I
decided not to include any thunder in the Sonora...Junction...or
Brady terminals. If these terminals do have a thunderstorm it will
likely be very short lived. For San Angelo...I did include a tempo
group for thunder from 06z to 08z...given current thunderstorm
complex there. For tomorrow afternoon...I decided to include
prob30 groups for thunder at all five terminals. The NAM
generates a broad quantitative precipitation forecast area across most of west central Texas
tomorrow afternoon. So...I believe the prob30 groups for all five
terminals look reasonable. The NAM also brings a weak cold front
into west central Texas tomorrow and stalls it near a Sterling
City to Brownwood line by tomorrow afternoon. Thus...look for
light surface winds tomorrow.
Huber
&&
Previous discussion... /issued 1125 PM CDT Monday Jun 17 2013/
Update...
Severe Thunderstorm Watch number 323 has expired. Plus...satellite
imagery indicate a mesoscale convective complex has moved into
our western counties. We have coordinated with the river forecast
center...and we believe the threat of river flooding remains low
at this time. However...heavy rainfall is likely with this
complex. So...flash flooding is a possibility. Based on satellite
and radar trends over the last couple hours...I decided to
increase rain chances across our Concho Valley and Heartland
counties for the remainder of tonight. The latest RUC and NAM data
indicate the complex will likely continue to move slowly south for
the remainder of tonight. So...I also increased rain chances
across at least the northern parts of our northern Edwards Plateau
counties and our north West Hill country counties. The latest
alphanumeric products reflect these changes.
Huber
Previous discussion... /issued 730 PM CDT Monday Jun 17 2013/
Update...
Latest WSR-88D data indicate thunderstorms are slowly moving south
across the Big Country. Based on the severe history of some of
these thunderstorms...and after coordination with Storm Prediction Center...we decided to
extend the Severe Thunderstorm Watch south to include our northern
three Concho Valley counties and our northern Heartland counties.
I updated our hazard grid to include these new counties and issued
a new watch County notification for Severe Thunderstorm Watch 323.
Our latest zone product reflects this update.
Huber
Previous discussion... /issued 655 PM CDT Monday Jun 17 2013/
Discussion...
Look for thunderstorms across the Big Country this evening and
stratus to bring MVFR ceilings back to the Northwest Hill country
later tonight. See aviation below for details.
Aviation...
Look for challenging flight weather conditions to continue across
the Big Country this evening. Thunderstorms developed earlier this
afternoon along an old outflow boundary just north of Interstate
20 across the Big Country. The RUC indicates we could have an
mesoscale convective complex move into west central Texas from the
northwest later this evening. However...my confidence as to where
this complex may move across west central Texas...I decided not to
include any thunder in any of the terminals at this time...except
for Abilene. Later tonight...the NAM bring stratus and MVFR
ceilings back to Junction. For tomorrow afternoon...look for
thunderstorms to again develop across much of west central Texas.
Huber
Previous discussion... /issued 354 PM CDT Monday Jun 17 2013/
Short term...
/tonight into Tuesday/
A chance of thunderstorms tonight into Tuesday...mainly over the
Big Country...but all of west central Texas has a slight chance
of storms.
Thunderstorms were developing in an enhanced cumulus field in the
Big Country at 3 PM...associated with remnant outflow boundary
from a morning thunderstorm complex. Expect scattered
thunderstorms to develop and move slowly east or southeast over
the Big Country this afternoon and evening. A second complex of
storms will likely develop along a weak cold front...east of
Lubbock this evening...then move slowly south or southeast into the
Big Country and Concho Valley. It may be late evening for storms
to affect southern areas from San Angelo to Brownwood.
With sb convective available potential energy of 3000 j/kg...and 0-6 km shears up to 40 kts (big
country)this evening...some severe storms possible. Storm Prediction Center day 1
severe weather outlook has a slight risk of severe storms in the
Big Country...Concho Valley and northern Heartland.
There is a similar setup for Tuesday...with dissipating front in
the Big Country being the Focal Point for shower and
thunderstorm development. Again a few storms could be severe with
convective available potential energy over 2500 j/kg in the afternoon.
04
Long term...
the majority of the long term portion of the forecast will be
highlighted by hot and dry conditions as the subtropical ridge
becomes the dominant feature across the central Continental U.S..
Scattered convection is expected to be ongoing late Tuesday
afternoon and should linger into the evening hours. Low probability of precipitation
were included for all of west central Texas. Most of this activity
should wane by 9 PM but there is some indication that a decent middle
level wave diving southeast across The Rockies will aid in the
development of an mesoscale convective system propagating out of the High Plains and into
western North Texas. I did include low rain chances for Wednesday
morning...generally north and east of Abilene through 18z to
capture this potential. However...once this system moves
east...rain chances look to become very scarce through the
weekend.
Temperatures will warm into the middle 90s on Wednesday afternoon...creeping
into the upper 90s for Thursday and Friday. I would not rule out
the possibility that a few areas could reach triple digits but I
think this will be the exception rather than the rule. Expect min
temperatures during this time in the low/middle 70s with brief stratus
episodes over the southeast counties during the late night and
morning hours. Deep diurnal mixing will result in decreasing
dewpoints during the latter half of the work week...suggesting
that the afternoon cumulus field will become more sparse.
The 12z European model (ecmwf) has come more in line with the recent runs of the
GFS/Gem regarding the handling of the remnants of dew point 2. The 00z
European model (ecmwf) was bringing a persistent middle level wave up the Rio Grande
and lifting it north across West Texas over the weekend...very
similar to what was observed this past weekend. However...the
latest run is keeping any remnants well south of the area...
advecting it nearly due west into central Mexico and more in line
with the TPC forecast. Given the poor organization of this storm
and its proximity to land...the latest solutions look very
reasonable. Thus...no impact is expected anywhere near west
central Texas.
The medium range models all indicate a strong shortwave trough
moving across the northwest Continental U.S. Friday/Saturday but the
subtropical ridge is expected to hold strong over the Southern
Plains. However...middle level heights are expected to lower somewhat
as this system moves across the plains and flattens the ridge.
Johnson
&&
Preliminary point temps/pops...
Abilene 72 95 75 96 73 / 30 10 5 0 0
San Angelo 73 96 75 97 74 / 20 5 5 0 0
Junction 72 93 73 94 73 / 20 5 5 5 5
&&
Sjt watches/warnings/advisories...
none.
&&
$$
Huber/04/Johnson
