Texas Spring 2019

[gpsnowman]

if these clouds and drizzle hang out hard to get too excited imo

Agreed. The drizzle has stopped and the sun is trying to peek out but Irving is sitting at 69 degrees ATM.

[TheProfessor]

https://pbs.twimg.com/media/D4TYm5WW4AAI60U.jpg

https://pbs.twimg.com/media/D4Toj2FWkAAd8wB.jpg

Heh, I wonder if they used any of my hail data collection for this statistic lol.

[rwfromkansas]

Chris Robbins/iWeathernet says clouds starting to break west and won't have an impact on things. He is usually right, so will see. I think it's hard to deny it will limit things early east of DFW.

[TarrantWx]

Very impressive looking sounding IMBY from the HRRR at 01z. Hopefully storms line out pretty quickly. There's a little bit of VBV here, but the 0-1km SRH near 200 & STP near 4 is nothing to sneeze at.

[TexasStorm]

NWS sending ballon up at 18z per last discussion

[CaptinCrunch]

Here why I enjoy the guys here at the FTW NWS office

There is high confidence that all of the ingredients for a severe
weather event will be in place over the region this afternoon and
tonight, but exactly how it plays out remains uncertain primarily
due to a complex upper level pattern leading to waves of
organized forcing for ascent and subsidence. Meteorologists can
often get lost in the "parameter space" of forecasting severe
weather, meaning that countless numbers and indices relating to
the type and severity of the weather dominate the forecast and
conversation of it. In reality the upper level dynamics and the
physical response of the atmosphere to it is extremely important
and can make or break a severe weather event. Unfortunately this
piece is extremely difficult to forecast, both because these
features are aloft and difficult to sample which can lead to
numerical modeling errors. Likewise it is tough for human
forecasters to infer how the numerical model is handling those
features. So having said that, lets dive into the upper level
features that are critical to the forecast and will influence 3
separate potential severe convective events/areas.

The upper level low currently over Arizona is poised to enter the
state later today and pivot northeastward tonight. Rounding the
base of the trough will be two shortwaves, the first moving
across the region around midday and the second crossing the region
late tonight. Forcing for ascent will occur ahead of both of
these, but a wave of subsidence will spread across the region
late this afternoon and early evening in the wake of the first.
The upper trough maintains a positive tilt which means in the wake
of the first shortwave it is very likely that the winds near 800
mb will veer and weaken which will impact the low level shear
profile and help to keep the tornado threat from getting out of
hand. But ahead of the first shortwave may be a different story.

So the 3 areas and times of potential severe convection are...

1) Across the eastern and southeastern counties, east of a Hearne
to Corsicana to Bonham line, between 3 pm and 7 pm:

The early passage of the first shortwave means most of the area
will remain too cool and capped for convection. Across this
eastern area however, it`s possible that just enough daytime
heating and, more importantly, continued moisture advection will
result in enough uncapped instability for convective initiation
and severe weather. A lack of any boundary in this area will limit
surface convergence and therefore also may result in convection
struggling to organize. Typically this warm-advection driven
convection takes a long time to develop and intensify even in
unstable environments. The forecast soundings and severe weather
parameters in this area make us most concerned about a more
significant tornado threat than any other area of our CWA, but we
are also concerned about very large hail. We estimate based on a
basket of the CAMs that the potential for severe convection
anywhere in this region is about 40% meaning the severe weather
threat is more conditional (may not happen at all).

2) The northwest and north central part of the CWA, including the
DFW Metroplex, from 5 pm to 10 pm:

A dryline will likely reach a Bowie to Comanche line late this
afternoon. Unlike areas farther east, strong surface convergence
along the boundary is forecast and will help to provide a favored
zone for convective initiation. However, this region will likely
be in weak subsidence in the wake of the early day shortwave
during the peak heating hours of late afternoon. This could lead
to false convective starts and struggling convection despite a
very unstable and uncapped airmass as temperatures reach the low
80s with dewpoints in the mid 60s. In addition the early day
shortwave will lead to weaker winds in the 800 mb area and a
veer-back-veer profile in the lowest levels with a hodograph
depicting a pronounced kink due to these weaker winds. This type
of shear profile may be both good and bad. It should lower the
potential for strong sustained low level mesocyclones and thus the
tornado threat would be more isolated and brief. On the other
hand it may actually help convection initiate as there will be
less turbulent mixing and shear to decapitate infant updrafts.
Finally this shear profile would increase the potential for very
large hail as it would result in greater mid and upper level cloud
layer shear which is far more important for copious amounts of
large hail growth than just being unstable. Although we should
mention that it most certainly will be very unstable with MLCAPE
possibly near 3000 J/KG and a large amount of instability in the
hail growth zone. Several sounding analogs suggest that any mature
supercell in this area will have the potential to produce
baseball to softball size hail. If supercells do form and remain
isolated past 9 pm, we will have to closely monitor the 800 mb
flow as the approach of the next trough could bring more cyclonic
curvature in the low levels and lead to a higher tornado
potential. Remember, severe storms are still not a certainty in
this region as it is possible the subsidence wins out - but based
on the various CAMs we estimate a 60-70% chance there will be
severe weather somewhere in this area between 5 and 10 pm.

3) The entire CWA, but especially areas south of I-20 after 9pm:

The approach of the main upper trough axis will bring the second
shortwave across Central Texas resulting in strong forcing across
most of the region, but especially south of I-20. Moderate to
high instability and a weak cap will result in a rapidly
developing line of storms west of I-35 that should race eastward
into the overnight hours. Storm mode suggests that while there
will be hail threat - it will not be as extreme as the other 2
potential events. Instead damaging winds look like the primary
threat with this squall line, but the possibility remains there
will be some brief embedded tornadoes along the line. Confidence
is high across Central and East Texas that this line of storms
will occur (with PoPs 80-100%) however the farther north one goes
the weaker and less organized the dynamic forcing is and thus
these areas may miss out on this round.

In summary, not everyone will see severe weather, but everyone
should prepare for it. It`s one of those days we ask people just
to stay plugged into your favorite source of weather information
so that you can act if need be - whether it`s moving a car
somewhere protected or seeking a safe shelter.

[bubba hotep]

Temps soaring into the 80s out West as clouds break up from West to East.

[CaptinCrunch]

SEVERE THUNDERSTORM WATCH OUTLINE UPDATE FOR WS 75
NWS STORM PREDICTION CENTER NORMAN OK
130 PM CDT WED APR 17 2019

SEVERE THUNDERSTORM WATCH 75 IS IN EFFECT UNTIL 800 PM CDT
FOR THE FOLLOWING LOCATIONS

TXC011-045-065-075-087-129-179-191-197-211-233-295-357-393-483-
180100-
/O.NEW.KWNS.SV.A.0075.190417T1830Z-190418T0100Z/

TX
. TEXAS COUNTIES INCLUDED ARE

ARMSTRONG BRISCOE CARSON
CHILDRESS COLLINGSWORTH DONLEY
GRAY HALL HARDEMAN
HEMPHILL HUTCHINSON LIPSCOMB
OCHILTREE ROBERTS WHEELER

[gpsnowman]

Temps soaring into the 80s out West as clouds break up from West to East.

Sun has been breaking through periodically in Irving with the temp jumping 5 degrees since I last posted.

[rwfromkansas]

My school district is requiring all events to be canceled after 5. Seems a bit much, but I wouldn't want kids caught outside in baseball hail in the slim chance it would happen directly over them either.

[Haris]

Curious what ends up happening in Austin. Models remain sorta choppy. In the sense that some bring a decent line while others show didly squat.

[weatherdude1108]

Seeing breaks in the clouds and periodic peaks of sunshine down here in Austin.

[bubba hotep]

At 1st glance, looks like 18z sounding is showing a stronger cap than models were thinking but waiting for SPC plot. This could keep early storms in check for DFW and points east but unclear what impacts that will have on later storms.

[rwfromkansas]

Now 81 with good sun IMBY. Mid-upper 80s on track.

[weatherdude1108]

Nice precipitation outlook for the next few weeks.

[Lagreeneyes03]

Surprised no watches up yet for the DFW Metro. I'm in Dallas and it still is looking pretty cloudy, perhaps the storms won't reach the severe levels being touted by media?

[WacoWx]

Anyone have a link to some good hi-def visible sat imagery.

[Shoshana]

Currently 87 here. Sun is currently out. Does that mean the weather will be more severe later?

[Ralph's Weather]

Clouds still hanging tough in E TX, still right near 70 all over E TX. Near 70 DPs but no heating so we will be relying solely on storms forming over N TX and moving this way it appears.

[weatherdude1108]

EWX discussion

000
FXUS64 KEWX 172005
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
305 PM CDT Wed Apr 17 2019

.SHORT TERM (Tonight through Thursday Night)...
Current surface observations across Texas show the dryline extending
across West Texas (roughly from a Childress to Snyder to Ozona line),
and the cold front pushing south across the Texas Panhandle, having
just made it through Amarillo. It is this cold front that will spur
on the thunderstorms expected tonight into Thursday morning. Current
short-term forecast soundings and the aircraft soundings from AUS and
SAT show the atmosphere still mostly capped across South Central
Texas.

With the capped atmosphere currently storms should hold off through
the rest of the afternoon and into the early evening hours. With the
dryline moving east and the front pushing rapidly south the front
will overtake the dryline and be the lift that South Central Texas
needs for storms. There is plenty of moisture in place with dewpoints
in the upper 60s and 70s. The HRRR and other high resolution
forecast models show storm initiation between 7pm and 9pm across the
Edwards Plateau. When storms do initially form the discrete storms
will have a very good chance of producing large hail to do the
environment with 2500 to 3000 j/kg of instability/CAPE. All of the
models show these discrete storms forming into a line of storms as
they approach the hill country between 10pm and 1am. With 50 knots or
more of bulk shear in place the severe weather threat will continue
as the line approach the I-35 corridor. With the transition into a
linear MCS the threat will also transition from a large hail threat
to a damaging straight-line wind threat within bowing sections of the
line. The line should approach the I-35 corridor between about 11pm
and 2am. Based on all of this a good portion of the Hill Country and
I-35 corridor have been included in the Enhanced Risk from the Storm
Prediction Center, with most of the area in a significant hail hashed
area as well. Basically our entire area is in the slight risk, again
mainly for the large hail and the damaging wind threat. There is a
low risk of tornadoes, but the main risk will be more to the NE
towards the ArkLaTex region.

As the storms push east of I-35 a new threat will be introduced.
While rainfall totals across the area will generally be 1/4 of an
inch to 1 inch, there has been increasing signals that parts of the
area east of I-35 could see isolated totals as high as 2-3 inches.
This could cause some localized minor flooding issues, especially in
areas that have seen decent rains of late. The line of storms will
continues its eastward progression and be east of the area by morning
rush hour on Thursday.

In the wake of the line of storms and cold front a drier airmass
filters in for Thursday. As skies clear strong north and northwest
winds increase. Some portions of the Rio Grande Plains could be close
to wind advisory criteria. In addition, with the lower relative
humidity values dropping down to 20-30 percent elevated to near
critical fire weather conditions are expected across the Rio Grande
Plains and Edwards Plateau. For the rest of the area afternoon highs
will be a few degrees below normal from the mid 70s to low 80s.
Overnight lows Thursday into Friday will also run a few degrees below
normal in the low to mid 50s.

&&

.LONG TERM (Friday through Wednesday)...
In the wake of the upper trough that will bring storms tonight into
Thursday morning northwest flow will build in aloft on Friday with
sunny skies continuing. With northerly flow aloft and at the surface
highs Friday will continue to run a few degrees below normal along
the I-35 corridor, with near normal temps along the Rio Grande in the
mid 70s to mid 80s. Southerly flow returns Saturday morning as an
upper level ridge works across Texas. Highs for the weekend will warm
into the 80s area wide, and should flirt with 90 degrees along the
Rio Grande Plains. Clouds return on Monday ahead of the next trough,
with continued seasonal temperatures. All of the long range models
(GFS, Canadian, and ECMWF) show the trough approaching Tuesday, and
moving across the OK/TX Red River Valley Wednesday into Thursday.
With the approaching trough and the moist atmosphere rain chances
begin Monday night and increase through the day Tuesday. Similar to
the system moving through today a cold front will approach Tuesday
night and Wednesday further enhancing rainfall.