ATL: HARVEY - Models

[Nimbus]

Precip continues to pile up. While intensity may be a factor the big story is going to be flooding IMO.

Very scary, I was kind of wispecting a rain forecast up the Arkansas border?

[SouthDadeFish]

Check out the 12Z SHIPS-RII forecasts! 70% chance of a 45-kt increase in the next 36 hours! That would bring Harvey up to 100 kt!

SHIPS Prob RI for 20kt/ 12hr RI threshold= 47% is 8.7 times sample mean ( 5.4%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 76% is 6.2 times sample mean (11.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 69% is 9.9 times sample mean ( 7.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 65% is 15.1 times sample mean ( 4.3%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 54% is 19.4 times sample mean ( 2.8%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 70% is 13.7 times sample mean ( 5.1%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 45% is 8.6 times sample mean ( 5.3%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 60% is 10.1 times sample mean ( 6.0%)

[stormlover2013]

I think ukmet is going to nail this !!

[ronjon]

Check out the 12Z SHIPS-RII forecasts! 70% chance of a 45-kt increase in the next 36 hours! That would bring Harvey up to 100 kt!

SHIPS Prob RI for 20kt/ 12hr RI threshold= 47% is 8.7 times sample mean ( 5.4%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 76% is 6.2 times sample mean (11.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 69% is 9.9 times sample mean ( 7.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 65% is 15.1 times sample mean ( 4.3%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 54% is 19.4 times sample mean ( 2.8%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 70% is 13.7 times sample mean ( 5.1%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 45% is 8.6 times sample mean ( 5.3%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 60% is 10.1 times sample mean ( 6.0%)

I'm thinking at the 11 am advisory NHC might raise the intensity forecast to a minimal CAT 3 based on this and other model runs.

[mcheer23]

Track likely will shift north. TVCN moved north

[KWT]

Check out the 12Z SHIPS-RII forecasts! 70% chance of a 45-kt increase in the next 36 hours! That would bring Harvey up to 100 kt!

SHIPS Prob RI for 20kt/ 12hr RI threshold= 47% is 8.7 times sample mean ( 5.4%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 76% is 6.2 times sample mean (11.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 69% is 9.9 times sample mean ( 7.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 65% is 15.1 times sample mean ( 4.3%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 54% is 19.4 times sample mean ( 2.8%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 70% is 13.7 times sample mean ( 5.1%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 45% is 8.6 times sample mean ( 5.3%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 60% is 10.1 times sample mean ( 6.0%)

I'm thinking at the 11 am advisory NHC might raise the intensity forecast to a minimal CAT 3 based on this and other model runs.

I'm guessing upto 90kts BUT with a clear note to those RI potentials that this could come in stronger than expected at the moment.

Those are impressive amounts, even 40kts in just 24hrs is a pretty good odds at the moment, over 50%!

[hohnywx]

I think ukmet is going to nail this !!

The UKMET shifted significantly westward at 0z...still east of the rest of the models though. We might end up seeing a consensus in the area it shifted to however with the more northerly component of Harvey occurring.

[hohnywx]

Check out the 12Z SHIPS-RII forecasts! 70% chance of a 45-kt increase in the next 36 hours! That would bring Harvey up to 100 kt!

SHIPS Prob RI for 20kt/ 12hr RI threshold= 47% is 8.7 times sample mean ( 5.4%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 76% is 6.2 times sample mean (11.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 69% is 9.9 times sample mean ( 7.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 65% is 15.1 times sample mean ( 4.3%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 54% is 19.4 times sample mean ( 2.8%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 70% is 13.7 times sample mean ( 5.1%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 45% is 8.6 times sample mean ( 5.3%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 60% is 10.1 times sample mean ( 6.0%)

I'm thinking at the 11 am advisory NHC might raise the intensity forecast to a minimal CAT 3 based on this and other model runs.

I think having it high-end cat 2 is the prudent thing to do right now. Show the potential without going all-in. If strengthening continues today, they could forecast a major at 5 PM.

[ROCK]

Harvey is turning out to be worst case scenario...in it is rapidly deepening at an alarming rate so close to land. Plenty of time to make a run at a major...IMO...A wind event plus rain is highly probable now...

[Tireman4]

Harvey is turning out to be worst case scenario...in it is rapidly deepening at an alarming rate so close to land. Plenty of time to make a run at a major...IMO...A wind event plus rain is highly probable now...

Rain event..certainty in the Houston area...now the wind event becomes more probable ( sustained Tropical Storm winds....at least)....I would think..not good...not good.


The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

[stormlover2013]

UKMET has been right now with strength wise that's why it has been the eastern one, yes did shift little bit west and I think that will be a good consensus, Just my opinion, stronger system, center relocated, models didn't have this so that's why I think UKMET is on to something

[HouTXmetro]

Stronger storm, the curvature of coast line, the tendency for more poleward motion, inland flooding, and the surge is very concerning for Texas Coast.

[Steve]

There's still a pretty good divergence of scenarios on the models for Part 2 of Harvey which is Days 4-6.

NAM 06Z (12km) - Only goes to 84 hours (3 1/2 days). Moves up toward Corpus Christi and bumps the coast playing around Rockport and Seadrift just south of Port Lavaca. End of the run it's spinning near Port Lavaca and Palacios. All of SE Texas and most of Southern LA over to Mobile are in a rain shield and feeder bands by then.

NAM 06 z (32km) - Only goes to 84 hours. Does about the same thing and spins over Port Lavaca area for probably a day. Massive rainfall in SE Texas and SW LA and is moving toward Galveston & Houston 970s-ish at the end of the run.

CMC 00Z - Washes out over South Texas and NE Mexico after hitting Brownsville. Possible energy back down, but CMC builds in a ridge or something that pushes everything South. A new storm busts out in EPAC and maybe a hint of low pressure back in the Southern Gulf. Possible, but I'm not a fan of this run. It only goes to a "tight" 980, but we're almost there now. I realize the resolution won't show true intensity.

EC - Moves in around Corpus Christi and then does what the models were showing yesterday around 12z - Initially it doesn't move much at all along the coast from 48 to 96 hours (essentially 7pm tomorrow night to 7pm Sunday Night). This is bad. It's back offshore on Monday at a healthy 994mb right about where it landfell and moves back up the coast to just south of Orange, TX. Between 144 and 168 hours (which is Monday-Tuesday night) it moves in probably into Cameron Parish, Louisiana near Cameron/Holly Beach/Hackberry and crosses Louisiana on a NE angle to where it's about right over Natchez/Tallulah at 168 hours but is moving. It then continues up toward Tupelo, and sort of washes out as a low over Northern Kentucky after that.

NAVGEM 06Z - On the coast near Corpus Christi in 48 hours (so that would be 1am Saturday). Goes a little north, stalls and then is back in the same spot as landfall at 90 hours but obviously weaker. It's emerging off the coast in 96 hours rides the coast S L O W L Y while slightly intensifying and is still not onshore in SW LA due south of Sulphur at 144 hours. This is the closest run to the EC but is a little south and slower with Part 2.

[ROCK]

https://my.sfwmd.gov/sfwmd/common/image ... s/storm_09

I think its time to watch for wobbles and jogs now in real time....any north / right wobbles could mean significant impacts for a larger group of population.

[Steve]

https://my.sfwmd.gov/sfwmd/common/images/weather/plots/storm_09

The aggregate of the major models comes to this: it looks like possibly 2 or more days with hurricane conditions under the eyewall while it's down in Nueces and Calhoun Counties. You don't want to be in that unless you have a serious constitution to stick that out and a serious structure to occupy. There will be points that will see tropical storm conditions for up to 3 days or so. You don't see that type of scenario very often. The last hurricane to hit the US was Isaac in 2012. When it came in near New Orleans, Baton Rouge (where a ton of people evacuated to) ended up in the northern eye wall for a few hours. Power was out and it was a mess up there, and it was probably mostly tropical storm conditions with gusts to hurricane strength. That wasn't even a trial run for what will happen right along the coast and inland this time.

In my opinion (based on modeling), if you are anywhere near Corpus Christi, be prepared for possibly 2 days of hurricane conditions and longer in Tropical Storm conditions. If you are north of there, prepare for inundating rainfall at first, and then we see what comes later. Houston, Baytown, the Triangle, and all points south of there in SE TX will get swamped. It could rain for 3-4 days straight in certain areas. You also don't see that very often. It appears that we will have very weak or stuck steering in place more similar to what you see early in the season. This would seem to be the type of scenario you'd get with a tropical depression in June. But it's late August, and this will be a serious hurricane. Think about it. When does it rain for 3-4 days straight?

[Thetxhurricanemaster]

The NAM 3K lol shows the strongest storm in history with pressure of 876 MB that would be deadly !!! Take it with a grain of salt

[Steve]

The NAM 3K lol shows the strongest storm in history with pressure of 876 MB that would be deadly !!! Take it with a grain of salt

It looks like you're really going to get smacked. You said you were good and had what you needed. I could see y'all taking a prolonged historic beating if ECMWF and NAVGEM are close. If you have anywhere you can park your vehicle(s) high like in a downtown garage or something, you might consider. I think y'all drain pretty well down there, but with the tides and endless surge, the outlet channels are liable to be backed up. If you end up being right from yesterday and it hits a bit farther south, it's an onshore flow for as long as it sits and spins below you. I know you know that. Lots of possibilities, all pretty troubling. Best to you and everyone down that way.

[ROCK]

The NAM 3K lol shows the strongest storm in history with pressure of 876 MB that would be deadly !!! Take it with a grain of salt

eh thank goodness the NAM is poor with TC intensity...

[Steve]

The NAM 3K lol shows the strongest storm in history with pressure of 876 MB that would be deadly !!! Take it with a grain of salt

eh thank goodness the NAM is poor with TC intensity...

For sure. The 12z's are running now. Looks like 12 & 32km take it in a little north of Corpus, spin it and then pull it up heading for Houston but moving after the loop in the 54 hour range. We'll see how they finish.

[hd44]

https://www.tropicaltidbits.com/storminfo/09L_gefs_latest.png
Gefs do the same track as euro. Inland..stall and back over gulf.