MAY 2019: Wednesday Storm Complex/Scattered Showers To End May

[srainhoutx]

Summer is here. Time to start watching the sea breeze, PWATS, MJO, and easterly waves for rain...

Speaking of the Madden Julian Oscillation, we should be in a somewhat favorable stage for potential tropical mischief as the end of May nears. I do see the models attempting to spin up something either in the Eastern Pacific or the Western Caribbean as the monsoonal gyre establishes over Central America in about 7 to 10 days.

[Cromagnum]

Mosquito plaque is firing up now. Big, aggressive ones that bite hard in my yard today.

[unome]

an interesting stat from this tweet by Brian Brettschneider, @Climatologist49

https://twitter.com/Climatologist49/sta ... 2883337216

There are both 90% Above Normal and 90% Below Normal probabilities for the Lower 48 on the latest CPC 6-10 Day Outlook. This is the 5th such occurrence in the last 5 years [2/13/18, 9/30/18, 10/1/18, & 10/2/18].

[Rip76]

Couple of Gulf streamers popping up.

[jasons2k]

Rain chances tonight went from 70% down to 60%. Downward trend...

[unome]

I might be a little on-edge if I had Meso Discussion 666 over my area

Mesoscale Discussion 0666
NWS Storm Prediction Center Norman OK
0651 AM CDT Sat May 18 2019

Areas affected...much of northwest/north Texas into southern
Oklahoma

Concerning...Tornado Watch 180...

Valid 181151Z - 181345Z

The severe weather threat for Tornado Watch 180 continues.

SUMMARY...The threat for damaging wind or brief tornadoes persists
within the watch area, and will likely extend downstream into the
remainder of north Texas and southeast Oklahoma later this morning.
As such, watch extensions and/or a new watch may be needed.

DISCUSSION...A large complex of mixed-mode severe storms continues
to evolve over much of northwest into central TX, with a primary
line of storms from near Wichita Falls southwestward to San Angelo.
Ahead of this line, sporadic supercells have been ongoing with
possible tornadoes earlier.

The main line of storms is expected to dominate the severe threat in
terms of areal coverage, but isolated cells may develop at any time
in the moisture-rich air mass to the east. Early day soundings show
steep lapse rates aloft which will favor hail in any cell. Shear
profiles in the low-levels are quite favorable for rotation as seen
on area VWPs, but hodographs are relatively short above 3 km.
Isolated brief tornadoes will remain possible with any lone cells,
with damaging winds eventually the most likely threat with the line.

The primary tornado threat will be later today over northeast TX,
eastern OK and western AR when low-level shear will be greatest.

..Jewell.. 05/18/2019

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...TSA...FWD...OUN...SJT...LUB...MAF...

[unome]

looking kinda wicked, Abilene to San Angelo areas

https://nwschat.weather.gov/lsr/#HGX,AM ... 90459/1110
https://mping.ou.edu/display/
http://tempest.aos.wisc.edu/radar/sp3comphtml5.html

[srainhoutx]

Tornado Watch hoisted until 5 PM well to the NW of Houston...

[Kingwood36]

Any of this supposed to come in around here?

[redneckweather]

Any of this supposed to come in around here?

Not seeing any of the models bringing that line into Southeast Texas which is why it is quiet in here.

[srainhoutx]

Cap holding strong along and S of the I-10 Corridor. The SPC dropped the Slight Risk S of I-10 with their latest Update. Strong to Severe Thunderstorms still look possible for the Hill Country into College Station and on N and E.

Mesoscale Discussion 0669
NWS Storm Prediction Center Norman OK
1211 PM CDT Sat May 18 2019

Areas affected...Parts of central through northeast Texas into
southeastern Oklahoma and adjacent southwest Arkansas

Concerning...Tornado Watch 181...

Valid 181711Z - 181815Z

The severe weather threat for Tornado Watch 181 continues.

SUMMARY...The risk for severe winds may increase across parts of the
Red River Valley, toward the Ark-La-Tex, through 1-3 PM CDT, while
potential for severe hail and a couple of tornadoes increases in a
possible corridor of developing supercells across the Texas Hill
Country through northeastern Texas.

DISCUSSION...The southern flank of the extensive ongoing mesoscale
convective system is maintaining strength, with additional storms
forming to the south of the primary cold pool, east of the dryline
into portions of the Edwards Plateau. Activity is largely oriented
parallel to 30-40 kt southwesterly deep layer ambient mean flow,
resulting in only a modest general eastward progression. However,
as the environment continues to warm ahead of the strengthening cold
pool, the risk for potentially damaging winds may increase along
east-northeastward surging segments of the gust front.

Furthermore, as stronger upper support for large-scale ascent
continues to gradually pivot across/northeast of the Red River
Valley, toward the lower Missouri Valley, the primary convective
mode across the Texas Hill country into northeast Texas may trend
discrete/supercellular through 18-20Z. Residual mid-level capping
associated with warm elevated mixed-layer air may suppress the
development of widespread convection, but strong deep layer shear in
the presence of moderate to large mixed-layer CAPE (2000-3000+ J/kg)
will provide a favorable environment for supercells. It appears
that southerly 850 mb flow will remain strong enough to contribute
to low-level hodographs supportive of a risk for tornadoes, in
addition to severe hail.

..Kerr.. 05/18/2019

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LZK...SHV...TSA...HGX...FWD...OUN...EWX...SJT...

[Cromagnum]

Wind is quite fierce with very humid air blowing through. Amazed that we are always capped down here.

[davidiowx]

Wind is quite fierce with very humid air blowing through. Amazed that we are always capped down here.

Yea it really is! Is there a reason the areas S of I-10 have been having the cap so frequently lately? I assume the GoM has something to do with it, but you would think the moist air and wind convergence would lead to some type of development when it gets closer to our area later this afternoon/evening.

[mckinne63]

Wind is quite fierce with very humid air blowing through. Amazed that we are always capped down here.

Yep. I keep looking outside and saying "it is missing a good chance to rain." Darn cap!

[srainhoutx]

Tornado Watch issued for Burleson, Brazos, Madison and Houston Counties until 8 PM

[sau27]

Wind is quite fierce with very humid air blowing through. Amazed that we are always capped down here.

Yea it really is! Is there a reason the areas S of I-10 have been having the cap so frequently lately? I assume the GoM has something to do with it, but you would think the moist air and wind convergence would lead to some type of development when it gets closer to our area later this afternoon/evening.

The cap has more to do with warm air being blown in from higher elevations from Mexico. With a persistent southwesterly upper level flow that warm air gets streamed in here at the upper levels. That is on top of the fact that our more southern latitude keeps the cold upper level cores (which would erode the cap) of these storm systems further north.

[DoctorMu]

Looks like one last round of severe weather - it's been a weekly event in the NW counties.

Rotating cells possible in the evening. Maybe 1/2 to 1 inch of rain.

[DoctorMu]

Wind is quite fierce with very humid air blowing through. Amazed that we are always capped down here.

Yea it really is! Is there a reason the areas S of I-10 have been having the cap so frequently lately? I assume the GoM has something to do with it, but you would think the moist air and wind convergence would lead to some type of development when it gets closer to our area later this afternoon/evening.

The cap has more to do with warm air being blown in from higher elevations from Mexico. With a persistent southwesterly upper level flow that warm air gets streamed in here at the upper levels. That is on top of the fact that our more southern latitude keeps the cold upper level cores (which would erode the cap) of these storm systems further north.

Yep. The gradient of the cap effect is pretty steep between Hearne and Navasota. The GoM reduces the cap effect for Mississippi and Alabama, and thus they have a higher risk of tornadoes than Houston on average.

[unome]

Looks like one last round of severe weather - it's been a weekly event in the NW counties.

Rotating cells possible in the evening. Maybe 1/2 to 1 inch of rain.

I've been enjoying the rain, have not had to water the lawn, except in spots, since last fall - can do without the severe stuff though. Hope y'all stay safe, has been nasty today in parts of TX

[srainhoutx]

Folks in Grimes, NW Harris, Montgomery, Waller & Walker Counties may see a shot at a strong storm this evening. The last couple of runs from the HRRR (High Resolution Rapid Refresh) model does suggest a couple of stronger cells may develop as the line of storms to our West pushes closer.