May 2021:

[Stratton20]

Yeah definitely need to keep an eye on those feeder banda for sure

[Cpv17]

Pouring here. Looks like I’m caught in one of those bands.

[srainhoutx]

Mesoscale Precipitation Discussion 0222
NWS Weather Prediction Center College Park MD
333 AM EDT Sat May 22 2021

Areas affected...Middle and Upper Texas Coast

Concerning...Heavy rainfall...Flash flooding possible

Valid 220731Z - 221300Z

Summary...Wave of low pressure moving onshore near Matagorda Bay
will continue to lift northwest through the morning. East of the
center, persistent moist flow from the Gulf of Mexico will produce
bands of rainfall with rain rates of 2"/hr at times. Training of
these cells may produce 2-4" of rainfall and isolated flash
flooding.

Discussion...Surface low pressure lifting northwest out of the
Gulf of Mexico is moving onshore the Middle Texas coast early this
morning. This low is clearly evident on the KHGX WSR-88D
reflectivity as spiraling rain bands rotating around the center in
the vicinity of Matagorda Bay. Recent rain rate estimates have
been as high as 1.5"/hr southwest of Houston, TX, and recent
trends in both radar and GOES-E IR imagery indicate convection is
intensifying as it pivots onshore.

As the low continues to lift northwest, it will likely lead to an
enhancement in both intensity and coverage of showers and
thunderstorms. Deep SE flow east of the low will increase in a
subtly pinched gradient, and 850mb inflow is progged to reach
30-40 kts this morning. This will advect extremely high PW air
onshore, sampled by GPS observations to be near 2.25", which would
eclipse the daily record. Additionally, as the low lifts further
northwest, this will drive better instability inland within this
tropical/Gulf of Mexico airmass, allowing for an expansion of the
coverage of showers and thunderstorms. This is already beginning
to occur, with the strongest convection occurring within an
expanding plume of SBCape >1500 J/kg according to the recent RAP
analysis. Additionally, a dry slot noted in CIRA LPW and the 850mb
dewpoint fields lifting south of the low could locally drive
better ascent to further enhance rain rates.

Although individual cells are likely to move quickly W/NW at
20-30kts following the mean wind, training of echoes is nearly
certain within any banded structures. The HRRR is initializing too
far SW with the surface low and best convection this morning, but
has trended NE to get into better alignment with the current
radar. However, the HREFmean and FV3LAM are preferred for the next
several hours. This guidance suggests rain rates potentially
reaching 2"/hr, which could produce 2-4" of rainfall in isolated
locations. This rain is likely to occur atop extremely saturated
soils due to recent 7-day rainfall more than 600% of normal, so
any training echoes could quickly become runoff, and isolated
flash flooding is possible as the low lifts northwest.


Weiss

ATTN...WFO...CRP...EWX...HGX...LCH...

[jasons2k]

We’ve got to be the only place on the planet where you can be on the east side of a tropical cyclone and still not see a drop.

[davidiowx]

We’ve got to be the only place on the planet where you can be on the east side of a tropical cyclone and still not see a drop.

Lol right! It looks like some rains will be moving in later today though. A lot of moisture offshore and we will see what the sun can do to help.

[weatherguy425]

We’ve got to be the only place on the planet where you can be on the east side of a tropical cyclone and still not see a drop.

Greatest moisture values are displaced well east and southeast of the primary low - that’ll be dragged in over the next few days. It may not be widespread and could focus southwest of the Metro... but greater coverage than today. Technically, isn’t a tropical system.

[jasons2k]

I call a spade a spade. Technically it didn't get the official upgrade by the NHC but that's splitting hairs. That thing clearly closed-off before landfall. They could have designated it and nobody would have disagreed on the merits. Meteorologically speaking, this is no different than any other landfalling weak TD.

[weatherguy425]

I call a spade a spade. Technically it didn't get the official upgrade by the NHC but that's splitting hairs. That thing wound-up before landfall. They could have designated it and nobody would have disagreed on the merits. Meteorologically speaking, this is no different than any other landfalling weak TD.

But, when it comes to rainfall production and efficiency, there are some differences. That was my only note.

[jasons2k]

I call a spade a spade. Technically it didn't get the official upgrade by the NHC but that's splitting hairs. That thing wound-up before landfall. They could have designated it and nobody would have disagreed on the merits. Meteorologically speaking, this is no different than any other landfalling weak TD.

But, when it comes to rainfall production and efficiency, there are some differences. That was my only note.

But the difference is because a boatload of dry-air mixed-in, not because the NHC held-off on the designation, right?

From a physics and meteorological standpoint, how is this different than a 'designated' system that has entrained a ton of dry air and is basically falling apart at landfall? This thing will bring more rain to Texas than TS Don did. It has more efficient rainfall production now than TS Don did during its last advisory. Not a great comparison because there is no doubt that TS Don was indeed officially a designated tropical cyclone out over the Gulf....but I use it to illustrate that the NHC's designation of something doesn't always accurately align 100% with what is happening from a meteorological standpoint. That's why we have post-analysis. That's why Josh Morgerman did a fantastic research paper concluding that TS Don was no longer a TS well before the NHC officially dropped the designation.

If the NHC had designated this system as a TD on the landfalling advisory as TD#2 I don't think we'd be having this debate at all. I don't think you'd see any pro-mets wringing their fists saying "that's not a TD!" I know Bastardi wouldn't be in this case. We'd be simply discussing how the dry air, shear and cool waters prevented this "TD#2" from getting upgraded to Bill.

[weatherguy425]

I call a spade a spade. Technically it didn't get the official upgrade by the NHC but that's splitting hairs. That thing wound-up before landfall. They could have designated it and nobody would have disagreed on the merits. Meteorologically speaking, this is no different than any other landfalling weak TD.

But, when it comes to rainfall production and efficiency, there are some differences. That was my only note.

But the difference is because a boatload of dry-air mixed-in, not because the NHC held-off on the designation, right?

From a physics and meteorological standpoint, how is this different than a 'designated' system that has entrained a ton of dry air and is basically falling apart at landfall? This thing will bring more rain to Texas than TS Don did. It has more efficient rainfall production now than TS Don did during its last advisory. Not a great comparison because there is no doubt that TS Don was indeed officially a designated tropical cyclone out over the Gulf....but I use it to illustrate that the NHC's designation of something doesn't always accurately align 100% with what is happening from a meteorological standpoint. That's why we have post-analysis. That's why Josh Morgerman did a fantastic research paper concluding that TS Don was no longer a TS well before the NHC officially dropped the designation.

If the NHC had designated this system as TD on the landfalling advisory as TD#2 I don't think we'd be having this debate at all. I don't think you'd see any pro-mets wringing their fists saying "that's not a TD!" I know Bastardi wouldn't be in this case. We'd be simply discussing how the dry air, shear and cool waters prevented this "TD#2" from getting upgraded to Bill.

I’m not just referring to the national hurricane center and the lack of an upgrade. Structurally, this system remains a bit different regardless of dry air ingestion; Distribution of impacts,. The national hurricane center has an amazing group of meteorologists and upgrades and downgrades are made off of data.

I’m saying that this “is not the only place on Earth” where you’ll be rainless on the east side of a landfalling tropical system. Haha. I’n only pointing out that there are some reasons why more rain can be expected over the next few days... partially because of structural differences between a true tropical system and this one.

[TexasBreeze]

It reminded me of an epac system when it moves from warmer to cooler water and becomes a swirl of clouds with little bursts of convection during the wind down phase.

[jasons2k]

But, when it comes to rainfall production and efficiency, there are some differences. That was my only note.

But the difference is because a boatload of dry-air mixed-in, not because the NHC held-off on the designation, right?

From a physics and meteorological standpoint, how is this different than a 'designated' system that has entrained a ton of dry air and is basically falling apart at landfall? This thing will bring more rain to Texas than TS Don did. It has more efficient rainfall production now than TS Don did during its last advisory. Not a great comparison because there is no doubt that TS Don was indeed officially a designated tropical cyclone out over the Gulf....but I use it to illustrate that the NHC's designation of something doesn't always accurately align 100% with what is happening from a meteorological standpoint. That's why we have post-analysis. That's why Josh Morgerman did a fantastic research paper concluding that TS Don was no longer a TS well before the NHC officially dropped the designation.

If the NHC had designated this system as TD on the landfalling advisory as TD#2 I don't think we'd be having this debate at all. I don't think you'd see any pro-mets wringing their fists saying "that's not a TD!" I know Bastardi wouldn't be in this case. We'd be simply discussing how the dry air, shear and cool waters prevented this "TD#2" from getting upgraded to Bill.

I’m not just referring to the national hurricane center and the lack of an upgrade. Structurally, this system remains a bit different regardless of dry air ingestion; Distribution of impacts,. The national hurricane center has an amazing group of meteorologists and upgrades and downgrades are made off of data.

I’m saying that this “is not the only place on Earth” where you’ll be rainless on the east side of a landfalling tropical system. Haha. I’n only pointing out that there are some reasons why more rain can be expected over the next few days... partially because of structural differences between a true tropical system and this one.

I see what you're saying now. And I was more focused on the short-term and what is happening now. I think a case could be made either way. Is it on the cusp of having a true 'warm core' versus not, etc. - I think it's still debatable. When I look at current obs, satellite, radar - to me - that feature is not a typical mid-latitude MCS or MCV or anything like that.....it's a dying tropical cyclone.

[Cromagnum]

So wild that this little swirl seemingly reduced rain this weekend. Very unique.

[jasons2k]

That first time in 2021 that an onshore tropical disturbance that was almost a depression, looks even better after its inland. pic.twitter.com/jc14FfaSpA
-- Jim Cantore (@JimCantore) May 22, 2021

https://twitter.com/JimCantore/status/1 ... 9293048835

[Cpv17]

1.50” here not too shabby.

[unome]

I’m not just referring to the national hurricane center and the lack of an upgrade. Structurally, this system remains a bit different regardless of dry air ingestion; Distribution of impacts,. The national hurricane center has an amazing group of meteorologists and upgrades and downgrades are made off of data.

this - thank you

[djmike]

11.25” for the week. Im happy with that.

[Cpv17]

11.25” for the week. Im happy with that.

21” for me since April 30th. Love it!! And a lot more on the way in the coming days for my area.

[TexasBreeze]

I feel much better about rain and moisture heading to summer for Texas now than I did a few weeks ago!

[jasons2k]

I’m not just referring to the national hurricane center and the lack of an upgrade. Structurally, this system remains a bit different regardless of dry air ingestion; Distribution of impacts,. The national hurricane center has an amazing group of meteorologists and upgrades and downgrades are made off of data.

this - thank you

This is true, but even they admit they don't always get it right in real-time. That's why we have post-analysis.

Andrew was upgraded to a Cat 5 many years after the fact - I believe it was 10 years later.