July 2020

[Andrew]

00z models overall have trended south so I expect the NHC to start trending that way too. Might see a shift 25-50miles south on the next update from them.

[Rip76]

Just not that much there tonight.

[Andrew]

Just not that much there tonight.

True, but some deeper convection is forming over the center so that will be something to watch overnight.

[Cpv17]

Just not that much there tonight.

True, but some deeper convection is forming over the center so that will be something to watch overnight.

I don’t understand why the models have the sw side of this storm as the dirty side as it comes ashore and hardly anything north and east of the center? I just want a couple inches of rain at least.

[don]

Yeah its looking like the Port Aransas area may be the location of landfall.One thing Ive noticed with the models is that they expand the rain shield greatly once the storm makes landfall. With a strong onshore flow feeding into southeast Texas and high PW's im not quite buying into the low rainfall amounts the global models are depicting just yet. I will like to see what the mesoscale models show once we get into range as far as qpf amounts goes.

[Rip76]

Just not that much there tonight.

True, but some deeper convection is forming over the center so that will be something to watch overnight.

I don’t understand why the models have the sw side of this storm as the dirty side as it comes ashore and hardly anything north and east of the center? I just want a couple inches of rain at least.

Maybe dryer air on the north side, pushing the most of the weather southward?

[Andrew]

Just not that much there tonight.

True, but some deeper convection is forming over the center so that will be something to watch overnight.

I don’t understand why the models have the sw side of this storm as the dirty side as it comes ashore and hardly anything north and east of the center? I just want a couple inches of rain at least.

Well the storm is more organize and isn't sheared like some tropical storms are so this allows for a more vertically stacked system. That is why models are picking up on stronger banding near the center. With that said, I still think banding will occur several miles away from the center, it will just likely be more hit or miss. That is what you see in some of the more finely resolved models.

[Andrew]

00z ECMWF shifted south by a good degree and is a lot less intense, much closer to the GFS. Showing about .75 inches for most of us here.

[DoctorMu]

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.

I'd take 1-3 inches or precip. in a heartbeat. We've had 0.89 in of rain since June 24th.

[DoctorMu]

As we miss you here in Houston, Steve, I know ( at times) you miss Houston. Thank you again, for all you do both professionally here and personally with us.

Ditto. He’s awesome!

Three cheers for Steve! Indeed!

Yep. I hope I don't need a sharpie to get some decent rain out of TD8.

[Belmer]

No big changes overnight as it is still pretty disorganized. The NHC has shifted their cone southward and no longer includes the greater Houston area.

I saw last night recon was going to be heading out again around 4:45AM but I don't see anything on TT that they left. Delayed till later this morning I guess?

NHC 4am cone.png

[Scott747]

Not sure what to make of the 6z hurricane models. They both are significantly stronger and much further n towards Sargent. Though the HWRF definitely shows a weird track.

Curious if they will be mentioned in the next disco.

[srainhoutx]

Was just going to mention the HWRF and HMON solutions for 06Z. Regardless, heavy tropical downpours appear likely Friday into early Sunday. If we begin to see signs of banding thunderstorms, very heavy rainfall and potential flooding issues may be realized. Need to keep a keen eye out the next 36 to 48 hours or so.

[Cpv17]

Not sure what to make of the 6z hurricane models. They both are significantly stronger and much further n towards Sargent. Though the HWRF definitely shows a weird track.

Curious if they will be mentioned in the next disco.

Stronger system would go more north, weaker system would go more south. At least I think that’s how it works.

[Kingwood36]

I'm hearing chit chat that some think this will make a run at cat 1 status..what say you?

[cperk]

Was just going to mention the HWRF and HMON solutions for 06Z. Regardless, heavy tropical downpours appear likely Friday into early Sunday. If we begin to see signs of banding thunderstorms, very heavy rainfall and potential flooding issues may be realized. Need to keep a keen eye out the next 36 to 48 hours or so.

srainhoutx always good to hear from you and i just viewed both of those model runs and they do concern me.

[Belmer]

Not sure what to make of the 6z hurricane models. They both are significantly stronger and much further n towards Sargent. Though the HWRF definitely shows a weird track.

Curious if they will be mentioned in the next disco.

Stronger system would go more north, weaker system would go more south. At least I think that’s how it works.

In this case: a building mid/upper level ridge over the central Plains wouldn't allow TD8 to get too far north regardless of strength. In fact the stronger TD8 becomes the more likely scenario it moves more wsw which the Euro showed yesterday. Most models are in agreement of this movement once it approaches the TX coast.
I see the 12z GFS-Para was accounting for a much weaker ridge and breaking it down allowing TD8 to move north but latest runs have more aligned to global/meso runs... though still a bit weaker. I also don't put much stock into the GFS Para right now. It has had its fair share of hiccups this summer.

[Belmer]

Last few hours have shown quite a bit of improvement. Starting to tighten up and banding/outflow looking better and better with each frame. Hopefully we can get recon out there soon... still no word on why they cancelled this morning or when the next flight is.

Looking at buoy observations, still indicates this is a TD with ~20kts. Recon would likely find stronger winds though near the center with the blowup of convection. Upper low to its southwest is helping ventilate its outflow along with a nice anti-cyclonic flow overhead. Overall structure should only improve throughout the day. Hopefully HWRF/HMON don't verify, but I wouldn't completely discount a stronger storm . Also looks like it has slowed down the last few hours.


Edit to add: I see recon is on its way out there.

Black dot is the coordinates from the NHC 7am update on where the center is.

TD8.jpg

[don]

Looking a a few of the models this morning it looks like models may be catching up with the rainfall potential on the dirty side of the storm.

[srainhoutx]

RECON is in the air and on the way...