APRIL 2019: Warm & Muggy WX to End The Month

[Andrew]

The threat for severe weather will shift to the southeast later tonight, but I still think the largest threat for most will be heavy rain. Already seeing some flooding across the hill country, but it will be difficult to really pin down where the heaviest rain occurs until it actually happens. One thing to note also is a lot of the models show 3-5k Jules of CAPE across a lot of the region later this afternoon. Any storms that do pop up could have a threat for hail.

Below is a sounding from the HRRR that shows steep mid level lapse rate and we are rather lucky we have just enough capping that should keep things in check. There is just enough subsidence at the surface to offset some of the upward upper-level motion associated with the active flow.

Finally, by early tomorrow the GFS shows PWATs up to 1.7inches which will be near seasonal max for this region. Looking at Western Louisiana's PWATs it is rather impressive honestly. So we have to closely monitor tonight for any MCSs.

[jasons2k]

The sun is breaking out south of I-10.

[davidiowx]

Sun has been out for the past few hours here in Richmond

[Andrew]

The sun is break out south of I-10.

83-84 here with plenty of sun. It would be very interesting to see a sounding for this region right now.

[Cpv17]

It’s 84 here and partly cloudy in Wharton. Fuel for the fire.

[Andrew]

Areas around College Station will need to be monitored over the next couple of hours for any spinups. Strongest low-level winds are exiting the region slowly but conditions currently remain favorable.

[Cromagnum]

What time tonight is the primary threat? Everything so far has been 200-300 miles NW of Houston

[stormlover]

Everything was supposed to be farther north, next system not so much

[Andrew]

What time tonight is the primary threat? Everything so far has been 200-300 miles NW of Houston

Late tonight into tomorrow morning for most of SE Texas. I think the severe threat will be limited for much of us, but we will have to monitor for any training that occurs ahead of the main line. Look out between Del Rio and Laredo tonight to see what will be heading our way. Probably will see 1-3 inches widespread but 5-6 inches in isolated areas cannot be ruled out.

[stormlover]

Andrew- when will it end for the Beaumont area tomorrow ?

[DoctorMu]

Areas around College Station will need to be monitored over the next couple of hours for any spinups. Strongest low-level winds are exiting the region slowly but conditions currently remain favorable.

Message: NOAA-NWS-ALERTS-TX125CF1FDA434.SevereThunderstormWarning.125CF1FDBFF0TX.HGXSVRHGX.7d50e1692ba21c6f3e781fba48c62d86 from w-nws.webmaster@noaa.gov
Sent: 17:29 CDT on 04-06-2019
Effective: 17:29 CDT on 04-06-2019
Expires: 18:00 CDT on 04-06-2019
Event: Severe Thunderstorm Warning
Alert:
The National Weather Service in League City has issued a

* Severe Thunderstorm Warning for...
North central Brazos County in southeastern Texas...

* Until 600 PM CDT.

* At 529 PM CDT, a severe thunderstorm was located near Wixon Valley,
or 11 miles north of Bryan, moving northeast at 25 mph.
HAZARD...Quarter size or larger hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.

* This severe thunderstorm will remain over mainly rural areas of
north central Brazos County.
A Tornado Watch remains in effect until 600 PM CDT for southeastern
Texas.
HAIL...1.00IN
WIND...<50MPH

Big cell just north of Bryan. Some cells forming at the tail end of the line. Caldwell is under the gun.

Tornado Watch for the area expires in 25 minutes. There was a tornado detected on radar near Franklin less than an hour ago.

[Cpv17]

If the rain happens here across southeast Texas in the overnight and morning hours the severe threat should be limited and the really heavy rain threat would be limited to I would imagine.

[stormlover]

It’s going to happen

[Andrew]

Andrew- when will it end for the Beaumont area tomorrow ?

Showers will probably linger into Sunday afternoon

[Andrew]

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 39
NWS Storm Prediction Center Norman OK
555 PM CDT Sat Apr 6 2019

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of
Northern Louisiana
Eastern Texas

* Effective this Saturday afternoon and evening from 555 PM until
1000 PM CDT.

* Primary threats include...
A couple tornadoes possible
Isolated very large hail events to 2 inches in diameter possible
Isolated damaging wind gusts to 70 mph possible

SUMMARY...Clusters of strong to severe storms should persist for a
few more hours this evening with all hazards possible.

The tornado watch area is approximately along and 40 statute miles
either side of a line from 25 miles west of College Station TX to 70
miles northeast of Natchitoches LA. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU9).

[Andrew]

KCLL Special Sounding. Note it probably got taken out by lightning.

[Andrew]

One thing that is interesting to note is how there have been zero reported tornadoes so far. While that doesn't mean there weren't any tornadoes today, it does imply whatever did touchdown was most likely shortlived. This is common in situations where you have a very energetic environment (high CAPE) with limited shear. Low-level shear, in particular, was lackluster today for strong tornadoes and most were fortunate that was the case because there were several semi-discrete storms that had that "look". Just shows how important that 0-1km shear is when it comes to producing tornadoes.

[srainhoutx]

Saturday evening weather briefing from Jeff:

Severe Weather possible Sunday

As expected today…most of the activity has remained across central TX into our far northern counties where softball size hail was reported this evening in Houston County.

Stalled warm front has been the focus for repeated rounds of severe weather today from near San Marcos to north of Huntsville and activity continues to develop this evening although overall there is a slow weakening of the storms. Brief lull will be short lived as the next strong disturbance over NC MX is heading for SW TX and strong deep layer lift will begin to overspread an unstable air mass over the Rio Grande plains later this evening. Short range models show an explosion and then rapid evolution of a large thunderstorm complex over SW TX late this evening that roars ENE overnight across SC TX, the coastal bend, and SE TX by early Sunday morning. Model depiction of this complex looks like a large squall line with a large bowing segment or multiple bowing segments with potentially corridors of damaging winds. Air mass over the region overnight will favor severe weather with strong onshore low level flow helping to supply a steady feed of moisture. Capping that has kept much of the area south of HWY 105 dry today will be eroded rapidly with cooling aloft and strong lift overnight.

Thunderstorm complex should arrive into the SW/W sections of SE TX between 300-600am and then toward I-45 between 500-800am. Strong damaging winds will be possible with this line up to 60mph or even greater especially west of I-45. Will have to see how the initial line plows across the area and see where the outflow boundary will stall out on Sunday to determine if additional storms will be possible in the afternoon hours.

As for heavy rainfall, the lack of rainfall today over much of the area has maintained the dry soil parameters, and the recent model trends of a bowing thunderstorm complex generally points toward a brief bout of heavy rainfall with the main line. Still think 2-3 inches will be possible over much of the area, but dry soils should be able to handle. From College Station to Huntsville 1-2 inches of rain has fallen today and this area could see some flooding, but the activity on Sunday looks to focus more toward the south of this area…or across the area that has seen little rainfall today.

[srainhoutx]

Mesoscale Discussion 0272 NWS Storm Prediction Center Norman OK 0100 AM CDT Sun Apr 07 2019 Areas affected...portions of southern TX Concerning...Severe potential...Watch likely Valid 070600Z - 070730Z Probability of Watch Issuance...80 percent SUMMARY...Large hail and damaging wind gusts will be possible overnight into the early morning hours across much of southern Texas as a cluster of storms in Mexico cross the Rio Grande and shift eastward. DISCUSSION...The severe threat will continue to increase overnight as a cluster of storms over the higher terrain of Mexico shifts east across parts of the Hill Country and points south. This convection is being forced by increasing ascent as the southern stream shortwave trough ejects over northern Mexico. The downstream environment is characterized by a very moist boundary layer with upper 60s to low 70s dewpoints beneath midlevel lapse rates around 8-8.5 C/km. This is resulting in MUCAPE values around 2000-3000 J/kg. Low level easterly flow through the lowest 1km or so is relatively weak, ranging from about 10-15 kt, but should increase slightly with time. A quasi-stationary front is draped across the region from northern Maverick County east/northeast into east-central TX. Hi-res guidance suggests convection will organize and travel roughly along and south of this boundary in the more pristine warm sector airmass. Given very steep midlevel lapse rates, hail will be likely in embedded stronger updrafts/supercells. Storm mode could temper a more significant hail threat, though some very large hail cannot be ruled out. While boundary layer inhibition is quite strong at this point, strong forcing should be sufficient to weaken low level inhibition sufficiently for some damaging wind threat as well. Convection will track eastward across much of southern TX through the overnight hours and a watch will be within the next hour or so. ..Leitman/Thompson.. 04/07/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CRP...EWX...BRO...

[Andrew]

Going to have to watch near Brenham. Thunderstorms are erupting along the warm front and that is most likely going to be the region that could see some flooding. If we don't see training ahead of the line currently southwest of San Antonio, flooding will be limited for others further south. Still, need to keep an eye on that over the next couple of hours for additional development and severe wx.