July 2020

[Andrew]

I think the biggest key with this system for the Houston region is where the WNW/NW movement stops and the W/WSW movement begins. Most models currently have the system stalling off the coast of Galveston and then ridging build in and push the storm west. Shear is also looking like less and less of an issue so this may be more of a vertically stacked tropical system with moisture staying pretty close to the center of circulation. I know we will still be on the "dirty side" of the storm but the majority of global models that develop this have the heaviest precipitation staying pretty far south. More than likely we will probably see a rather sharp gradient over the region with the heaviest precipitation staying south and west of Houston. With that in mind, still a lot of details to workout over the next day or two and keep an eye on the NHC and NWS for the latest.

[Cpv17]

I think the biggest key with this system for the Houston region is where the WNW/NW movement stops and the W/WSW movement begins. Most models currently have the system stalling off the coast of Galveston and then ridging build in and push the storm west. Shear is also looking like less and less of an issue so this may be more of a vertically stacked tropical system with moisture staying pretty close to the center of circulation. I know we will still be on the "dirty side" of the storm but the majority of global models that develop this have the heaviest precipitation staying pretty far south. More than likely we will probably see a rather sharp gradient over the region with the heaviest precipitation staying south and west of Houston. With that in mind, still a lot of details to workout over the next day or two and keep an eye on the NHC and NWS for the latest.

This is what I was referring to this morning with my post. I started noticing it last night. Since the system is becoming better organized then it would make sense that the higher qpf totals would be closer to the center. Victoria to Corpus Christi area could be in the jackpot with the way it’s looking right now.

[DoctorMu]

In other news, one last good shot of rain coming-up before I turn my attention to the gulf for relief. That storm approaching IAH - I need that cluster to grow and make it up here. Don’t go poof on me now!

We got maybe 0.1 in in CLL in a brief shower. At least it's cloudy and under 90°F! It's still unsure how much of the incoming 91L rain will be this far north. Gonzalo I heard is the earliest named "G" storm in Atlantic Basin history. Somebody check that!

[DoctorMu]

Canadian sticking by a hurricane off the south Texas coast on August 1, while GFS brings down a cold front. An interesting next 2 weeks coming up, potentially.

[Texaspirate11]

SO Galveston wont get much rain with this?

[jasons2k]

Oh I’m quite sure I’ll be staring at dark clouds to my south, with an invisible force field set up along I-10, vaporizing anything that dares to water my lawn.

On Sunday morning, I had shut off my sprinklers until this Friday. I may have to go ahead and run them tonight.

Edit: the latest Canadian is laughing at me. Icon very similar. The heavier rain gradient of 2” (purple) - you could trace that along the coast from the Florida panhandle west all the way through AL/MS/LA down to Matagorda, and the coast is like a wall all along the precipitation gradient. Then it skips inland towards San Antonio. I think I’m in the 1.2” shade, but just miles away it quickly drops to under and inch. Not liking today’s model trends at all. I want a broad sloppy system with rain well to it’s north, not some storm making a run at cane status and bending WSW away towards Corpus.

[Cpv17]

Oh I’m quite sure I’ll be staring at dark clouds to my south, with an invisible force field set up along I-10, vaporizing anything that dares to water my lawn.

On Sunday morning, I had shut off my sprinklers until this Friday. I may have to go ahead and run them tonight.

Yeah, areas north of 10 may not get much out of this. We’ll see.

[djmike]

When will data get released with HH data ingested?

[srainhoutx]

When will data get released with HH data ingested?

That data should be in the 00Z suite of guidance.

[don]

I think the biggest key with this system for the Houston region is where the WNW/NW movement stops and the W/WSW movement begins. Most models currently have the system stalling off the coast of Galveston and then ridging build in and push the storm west. Shear is also looking like less and less of an issue so this may be more of a vertically stacked tropical system with moisture staying pretty close to the center of circulation. I know we will still be on the "dirty side" of the storm but the majority of global models that develop this have the heaviest precipitation staying pretty far south. More than likely we will probably see a rather sharp gradient over the region with the heaviest precipitation staying south and west of Houston. With that in mind, still a lot of details to workout over the next day or two and keep an eye on the NHC and NWS for the latest.

I agree the landfall location and direction after landfall will determine qpf amounts and locations. If the storm hits the middle Texas coast and heads west from there. Then the heaviest rains would be confined to the southwest portions of the area through the coastal bend region. But if the storm motion is more northwest pulling moisture further inland after landfall. Or if the storm makes landfall further up the coast a majority of southeast Texas would be in play for heavy rainfall. And of course how tight or broad the storm is will also have an affect. We will know more tomorrow as the models should start to converge on a solution more. Btw the 18z ICON shifted slightly north with a landfall around freeport putting more of southeast Texas in play than previous runs FWIW of course.

[Kingwood36]

No upgrade tonight it looks like...still to disorganized...maybe tomorrow it becomes a TS

[Cpv17]

8pm update by the NHC has increased the odds for development up to 90% now and mentions that tropical storm watches could be coming tonight.

[Cpv17]

There are two clusters of model consensus right now. One cluster has it headed towards Matagorda Bay and the other towards Corpus Christi Bay. The smart thing to do would be to split the difference down the middle imo. But still many variables at play.

[Cpv17]

The 18z suite of hurricane models just came out and all of them (HWRF, HWRF-P, HMON) shifted north.

[Kingwood36]

How far north...im in freeport

[davidiowx]

How about we get a CoC and the HH data into the models before we start predicting where landfall is... If it’s a weak storm the worse of the impacts could be hundreds of miles away from the landfall location.

[Cpv17]

How far north...im in freeport

Anywhere from Galveston to Rockport.

[Kingwood36]

Damn that's a hell of a jump

[Cpv17]

How about we get a CoC and the HH data into the models before we start predicting where landfall is... If it’s a weak storm the worse of the impacts could be hundreds of miles away from the landfall location.

Yep! The 0z suite tonight/tomorrow morning will be a lot more informative.

[srainhoutx]

91L 7:00 PM Update from Jeff:

USAF mission this afternoon into 91L over the central Gulf of Mexico found a broad, but weak surface low pressure system with winds generally less than 20mph. Additionally, the convective organization of the system has decreased slightly this afternoon, but when compared to yesterday at this time, the overall organization of the system has increased and 91L is well on the way to becoming a tropical depression. NHC gives the system at 90% chance of development over the next 5 days.

There has been little change in the overall track reasoning with 91L expected to move WNW for the next 48 hours around 8-11mph and then slow some as it nears the TX coast and possibly turn slightly to the left or west as mid level ridging builds westward across the southern US. Generally, most forecast guidance keeps the system as a broad area of low pressure to maybe a 40-50mph tropical storm with a landfall along the TX coastal bend between Corpus Christi and Palacios.

Some of the model guidance has become more aggressive today with the rainfall potential with this system, but this is a recent development in the model guidance and we will see if models begin to converge on totals and placement of some of the greater rainfall potential over the next 24-48 hours from the coastal bend into portions of the upper TX coast/SE TX area.

Impacts:

Rainfall:
Widespread rainfall amounts of 3-5 inches will be possible along and generally south of HWY 105 with higher isolated totals. North of HWY 105 rainfall amounts of 1-3 inches will be possible. There is likely to be swaths of higher rainfall amounts where training bands develop, but where this may occur is difficult to pinpoint at this time range.

Winds:
Winds will back to the NE late Thursday and increase on Friday especially across the coastal waters and coastal counties. ENE/E winds Friday of 20-30kts will be likely over the coastal waters of the upper TX coast with 15-25mph along the coast from Sabine Pass to Matagorda Bay. Inland from the coast, winds will generally be from the east at 10-20mph. Squalls advancing inland on Friday may bring stronger wind gust to 40-45mph.

Seas/Tides:
Seas will build into the 2-3 foot range late Thursday and 3-6 foot range on Friday (which is higher than WW3 guidance) since that model pulls from the GFS pressure fields and the GFS is not showing much development with this system. Given 3-6 foot swells on Friday into Saturday, wave run-up will be likely on the Gulf facing beaches with tides running 2.5-3.5 feet above MLLW (barnacle level). Generally these levels are below coastal flood thresholds, but could see some high water on Bolivar and the west end of Galveston at beach access points and near Surfside. Within Galveston Bay tides will run 1-2 feet above MLLW and could impact some low lying roads in Shoreacres and near the Lynchberg Ferry Landing.

All the above listed impacts are subject to change over the next 24-48 hours as 91L develops and impacts become more defined.

Tropical Storm Watches/Warnings will likely be required for portions of the TX and LA coast early Thursday.