MARCH 2021

General Weather Discussions and Analysis
Cromagnum
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Re: MARCH 2021

Post by Cromagnum » Mon Mar 22, 2021 7:44 am

I just see rain this week. What was the concern with severe weather?

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don
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Re: MARCH 2021

Post by don » Mon Mar 22, 2021 9:01 am

SPC Extended outlook has the eastern half of southeast Texas in risk of severe weather. The worst of the weather should be over dixie alley, but discreet supercells cannot be ruled out even here locally due to moderate shear and moderate CAPE values.

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0346 AM CDT Mon Mar 22 2021

Valid 251200Z - 301200Z

...DISCUSSION...
...Day 4/Thu - Eastern TX to the Central Gulf Coast States...

An upper shortwave trough over the Rio Grande/northern Mexico will
strengthen and become negatively tilted as it ejects northeast
across the Arklatex through Thursday evening, and to the Ohio Valley
by Friday morning. Intense shear will overspread the south-central
and southern U.S. ahead of the trough. Furthermore, strong low-level
warm advection will result in a broad warm sector ahead of a
deepening surface low and eastward-advancing cold front from the
Sabine Valley eastward across the central Gulf coast/TN Valley
vicinity.

Differences in the evolution of the surface low across the lower MS
and OH Valleys are still apparent in medium-range guidance. This is
mainly resulting in uncertainty in the position of the surface low
and cold front Thursday morning, and how far east each of these
features progresses by Friday morning. As a result, changes in
severe probabilities, especially on the western and northeastern
edges, are likely in the coming days. Nevertheless, weak to moderate
instability will overlap with favorable shear parameters and an
overall supportive pattern for severe convection. A couple of rounds
of severe storms could be possible, as some warm-sector development
may occur across the Lower MS Valley before a QLCS develops along
the surging cold front during the evening/nighttime hours. All
severe hazards will be possible with discrete warm-sector
supercells. Potential for damaging gusts and tornadoes will becoming
preferential with any upscale development along the cold front.
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Cpv17
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Re: MARCH 2021

Post by Cpv17 » Mon Mar 22, 2021 1:14 pm

Models aren’t looking good for rain over the next week or two especially south of I-10.

Cromagnum
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Re: MARCH 2021

Post by Cromagnum » Mon Mar 22, 2021 6:45 pm

Seeing talk of "mud showers" tonight. I just washed my truck before this evenings popcorn showers rolled through to get a free rinse. Guess that's going to be pointless afterall.

Cromagnum
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Re: MARCH 2021

Post by Cromagnum » Tue Mar 23, 2021 5:16 am

Hill Country was pretty bumpy last night.

Houston's turn for the AM commute.


...SIGNIFICANT WEATHER ADVISORY FOR GALVESTON...SOUTHEASTERN FORT
BEND...NORTHERN BRAZORIA...SOUTHWESTERN CHAMBERS AND SOUTHERN HARRIS
COUNTIES UNTIL 645 AM CDT...

At 601 AM CDT, Doppler radar was tracking a strenghtening strong
thunderstorms along a line extending from Sienna Plantation to near
Brazos Bend State Park. Movement was east at 35 mph.

Pea size hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Pearland, League City, southeastern Missouri City, Galveston
Causeway, Galveston Island West End, Texas City, Friendswood, Alvin,
Dickinson, La Marque, Santa Fe, southwestern Seabrook, Webster,
Hitchcock, Manvel, Kemah, Fresno, southern Clear Lake, Nassau Bay and
Danbury.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

Image

JDsGN
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Re: MARCH 2021

Post by JDsGN » Tue Mar 23, 2021 6:04 am

That was an intense thunderstorm here in Cypress in Fairfield. Haven’t seen lightening like that in a long time.

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jasons2k
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Re: MARCH 2021

Post by jasons2k » Tue Mar 23, 2021 7:56 am

Lots of lightning here but managed only .28”

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don
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Re: MARCH 2021

Post by don » Tue Mar 23, 2021 3:02 pm

The ingredients are there for some pretty strong storms but the situation is conditional based on rather the cap can break or not this Thursday.I think the cap may hold for now.

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Re: MARCH 2021

Post by txbear » Tue Mar 23, 2021 8:24 pm

don wrote:
Tue Mar 23, 2021 3:02 pm
The ingredients are there for some pretty strong storms but the situation is conditional based on rather the cap can break or not this Thursday.I think the cap may hold for now.
Ah there it is. I was waiting for that three-letter curse word to show up. Seems like we could've had a few rounds of severe weather with the recent setups of fronts and boundaries, but seems like the cap has kept that tampered down.

We've seen what can occur when the cap busts along the gulf coast (Dixie Alley, my goodness), but we don't see similar setups here. I can gather some of the differences between here and say West Texas/Panhandle and the like because we don't see the dry line and those types of dynamics. But I would gather that our conditions would mimic, to some extent, those in Dixie Alley. Our cap seems to be a bit more stout seems like one factor, but that's just speculation. Bit of a headscratcher for me.

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jasons2k
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Re: MARCH 2021

Post by jasons2k » Tue Mar 23, 2021 9:02 pm

We are closer to the dry Mexican highlands and SW flow aloft from there brings-in the cap.

SW flow aloft over much of “Dixie” is from the Gulf....moist, not hot and dry.

And yes there are often better jet dynamics to the north of here. One reason why the storms are so intense in OK, KS, AR, etc.

Thursday will be a close call. A few hours and a few degrees either way could make a big difference. I hope the system slows down just a tad and crosses later in the day, giving us a better chance of rain. One can hope...

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