ATL: LAURA - Models

[kevin]

GFS at 60 hours, dances around 955 mbar during 48 - 60 hours.

[catskillfire51]

GFS goes from 971- 957 but then back up to 960 then back to 957

[tolakram]

[PTrackerLA]

Looks like 12z GFS will be Louisiana again, slightly east at 60hrs

[stormlover2013]

 https://twitter.com/brooksweather/status/1297919525711740929

[tolakram]

[Kingarabian]

GFS and Euro showing the intensification rate timid compared to what normally happens during RI. They might be factoring in an ERC by the time it gets to the 950s and the system simply runs out of real estate to intensify. An ERC could be a wild card between a cat.3 and a Cat.4/Cat.5.

[Shell Mound]

GFS and Euro showing the intensification rate timid compared to what normally happens during RI. They might be factoring in an ERC by the time it gets to the 950s and the system simply runs out of real estate to intensify.

So far the GFS, ICON, and NAM have trended weaker and farther east at 12Z, despite having relatively decent initialisations for once. There seems to be more shear and mid-level dry air on these latest runs that are keeping Laura from intensifying, especially as it nears land. Like Gustav and Ike, Laura may not intensify very much over the Gulf of Mexico, especially in terms of wind speed, even if its pressure manages to drop early on. Shear and dry air will be worsening as it nears land, so it could actually start to weaken just before landfall, like Katrina, Rita, and most other recent N-Gulf systems, excluding Michael (2018). Even if the centre reforms farther west-southwest, the disheveled structure and sprawling circulation in the short term make an eastward shift likely, so the NHC may very well be correct in terms of track and intensity. Personally, I think most of the intensification may occur just after Laura bypasses western Cuba, then quickly reverse as it approaches the N Gulf and curves into the westerlies.

[HoustonFrog]

This is a freaking nightmare trying to decide what to do. Everyone keeps saying west but then all the official stuff says East

[Kingarabian]

GFS and Euro showing the intensification rate timid compared to what normally happens during RI. They might be factoring in an ERC by the time it gets to the 950s and the system simply runs out of real estate to intensify.

So far the GFS, ICON, and NAM have trended weaker and farther east at 12Z, despite having relatively decent initialisations for once. There seems to be more shear and mid-level dry air on these latest runs that are keeping Laura from intensifying, especially as it nears land. Like Gustav and Ike, Laura may not intensify very much over the Gulf of Mexico, especially in terms of wind speed, even if its pressure manages to drop early on. Shear and dry air will be worsening as it nears land, so it could actually start to weaken just before landfall, like Katrina, Rita, and most other recent N-Gulf systems, excluding Michael (2018). Even if the centre reforms farther west-southwest, the disheveled structure and sprawling circulation in the short term make an eastward shift likely, so the NHC may very well be correct in terms of track and intensity.

Hey Shell Mound good to hear from you.

IMO these run to run fluctuations are not signs of the models shifting towards a weaker system and its just the modeling being what it is. They've been generally ending up +5/-5 in pressure for Laura the past 48 hours (excluding the Euro which has been pretty wild for this system).

It's very similar to what we see in the EPAC. For us who track systems there, the models almost always come in with a 960-950mb peak but we always know its more likely than not the system peaks between 925-935 mb -- and more often than not, that's what usually happens (a much stronger system than forecast). I have the same exact feel for this system.

[Kingarabian]

12z UKMET:

TROPICAL STORM LAURA ANALYSED POSITION : 21.0N 79.7W

ATCF IDENTIFIER : AL132020

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 24.08.2020 0 21.0N 79.7W 1000 41
0000UTC 25.08.2020 12 22.5N 83.2W 995 47
1200UTC 25.08.2020 24 23.8N 86.3W 992 48
0000UTC 26.08.2020 36 25.1N 89.3W 984 54
1200UTC 26.08.2020 48 26.6N 91.8W 972 67
0000UTC 27.08.2020 60 28.5N 93.4W 954 74
1200UTC 27.08.2020 72 31.2N 93.5W 961 43
0000UTC 28.08.2020 84 34.2N 92.4W 974 41
1200UTC 28.08.2020 96 36.4N 90.5W 979 47
0000UTC 29.08.2020 108 37.7N 86.5W 978 37
1200UTC 29.08.2020 120 38.1N 79.7W 983 27
0000UTC 30.08.2020 132 39.8N 72.4W 976 44
1200UTC 30.08.2020 144 44.1N 65.2W 966 52

Not backing down in intensity. Looks like it shifted east again.

[otowntiger]

This is a freaking nightmare trying to decide what to do. Everyone keeps saying west but then all the official stuff says East

It is frustrating and confusing especially for folks that need to prepare- I would pay most attention to the official guidance.

[PTrackerLA]

12z UKMET:

TROPICAL STORM LAURA ANALYSED POSITION : 21.0N 79.7W

ATCF IDENTIFIER : AL132020

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 24.08.2020 0 21.0N 79.7W 1000 41
0000UTC 25.08.2020 12 22.5N 83.2W 995 47
1200UTC 25.08.2020 24 23.8N 86.3W 992 48
0000UTC 26.08.2020 36 25.1N 89.3W 984 54
1200UTC 26.08.2020 48 26.6N 91.8W 972 67
0000UTC 27.08.2020 60 28.5N 93.4W 954 74
1200UTC 27.08.2020 72 31.2N 93.5W 961 43
0000UTC 28.08.2020 84 34.2N 92.4W 974 41
1200UTC 28.08.2020 96 36.4N 90.5W 979 47
0000UTC 29.08.2020 108 37.7N 86.5W 978 37
1200UTC 29.08.2020 120 38.1N 79.7W 983 27
0000UTC 30.08.2020 132 39.8N 72.4W 976 44
1200UTC 30.08.2020 144 44.1N 65.2W 966 52

Wow huge shift into western LA.

[Kingarabian]

BTW the public UKMET runs in 12 hour intervals, so the exact landfall intensity would be near 950mb. It shows 961mb after its in land.

[jlauderdal]

This is a freaking nightmare trying to decide what to do. Everyone keeps saying west but then all the official stuff says East

100 miles either side of the nhc line prepare for a 3...they are the ones to follow for the track, they dont miss by much at 72h

[kevin]

It seems some models are shifting East, but at the same time going through the discussion & models threads I hear people saying about initializations being too far North and a new center possibly forming further South, which would lead to a more Western path. Tbh I think we won't know for sure until it clears Cuba, but once that happens there won't be that much time left until landfall. I hope it won't be bad, but I can imagine that evacuations could be chaotic if they're given relatively late due to the unpredictable path.

[BobHarlem]

UKMet (Blue line) with a big east shift from Port O'Connor, TX at the 0z to around Cameron, LA at the 12z:



Man I wish they were a little more consistent at 12z, this has got to be maddening to the NHC and everyone on the NW Gulf.

[Socalhurcnegirl227]

It seems some models are changing East, but at the same time going through the threads I hear people saying about initializations being too far North and a new center possibly forming further South, which would lead to a more Western path. Tbh I think we won't know for sure until it clears Cuba, but once that happens there won't be that much time left until landfall. I hope it won't be bad, but I can imagine that evacuations could be chaotic if they're given relatively late due to the unpredictable path.

Honestly, issuing evac warnings for everyone from houston to the panhandle would be best in the case it does go east or west

[Nederlander]

It seems some models are changing East, but at the same time going through the threads I hear people saying about initializations being too far North and a new center possibly forming further South, which would lead to a more Western path. Tbh I think we won't know for sure until it clears Cuba, but once that happens there won't be that much time left until landfall. I hope it won't be bad, but I can imagine that evacuations could be chaotic if they're given relatively late due to the unpredictable path.

Honestly, issuing evac warnings for everyone from houston to the panhandle would be best in the case it does go east or west

Panhandle of FL?? That would be insane and far more dangerous than using NHC guidance on the main threats of storm surge, flooding, and wind.

[Hypercane_Kyle]

Remind me, why are we looking at the NAM and ICON seriously again? Neither are used for track or intensity guidance, and for a good reason. Might as well post the NAVGEM too.