ATL: GRACE - Models

[wxman57]

For Grace, the UKMET has performed best, as it kept Grace south of Cuba. Consensus and NHC the worst at 120 hrs. GFS and NOGAPS generally the worst models.

http://www.atmos.albany.edu/facstaff/btang/tcguidance/al072021/

[aspen]

12z HWRF continues to trend weaker, with a Cat 2/3 making landfall in Veracruz.

[cycloneye]

12z HWRF continues to trend weaker, with a Cat 2/3 making landfall in Veracruz.

Cat 2/3 is a strong cane.

[Kingarabian]

Models still showing that this will cross over into the EPAC.

[aspen]

12z HWRF continues to trend weaker, with a Cat 2/3 making landfall in Veracruz.

Cat 2/3 is a strong cane.

Better than and not as ludicrous as a 130 kt Cat 4. It’s the trend that’s important: the HWRF has Grace take longer and longer each run to recover after moving over the Yucatán. We’ll have to wait and see how it is tomorrow night to judge of the HWRF is right.

[IcyTundra]

For the 2nd Mexico landfall 00Z ICON has 969 MB and GFS has 978 MB.

[kevin]

06z ICON initialized quite well (good position but a bit too weak, 992 mb). Shows pretty much no weakening due to Yucatan (goes to 995 mb, but immediately returns to 993 mb above water). Afterwards Grace quickly intensifies to 964 mb before landfall.

[aspen]

Last night’s 18z HWRF successfully predicted the 00z and 06z satellite presentations. Let’s see if it’ll be right about Grace emerging as an anemic TC.

[kevin]

Today's 06z models. It seems there is a consensus of a landfalling pressure of roughly 965 - 970 mbar. Winds are still more uncertain with models ranging from a high-end cat 1 (GFS) to a cat 3 MH.

GFS = 970 mb / 82 kt / Cat 1
ICON = 964 mb / 85 kt / Cat 2
HWRF = 972 mb / 89 kt / Cat 2
HMON = 969 mbar / 102 kt / Cat 3

[aspen]

18z HWRF shows Grace rolling off the Yucatán as a 55kt/990mb TS, which lines up very well with what recon has found so far. Just 12 hours later on this run, Grace is a convectively active 70-75 kt hurricane.

Update: peaks as a 961mb/110kt Cat 3 before landfall around 12-2am Saturday. This HWRF run has Grace 2 hours behind its current position, so take off 2 hours from the time of landfall on this run.

[IcyTundra]

0Z ICON has 975 MB at landfall. 18Z had 980 MB at landfall.

[ElectricStorm]

HMON keeps it in the 990's for another 9 hours and then BOMBS it to 960 before landfall. That's like 30mb in 18 hours!

[ElectricStorm]

HWRF also keeps it in the 990's for the next 9 hours and then bombs it into a major, but not as deep as HMON. Peaks at 968mb, landfalls at 970. Max winds on both models are pretty close to each other in the Cat 3 range at peak.

[kevin]

Even with only 24 hours to go, HMON is not backing down. 961 mbar, 117 kt MH landfall. If that verifies it would be the most significant non-Yucatan Atlantic landfall for Mexico in quite some time right? Which storm (if any) has ever made landfall on the Atlantic side of Mexico with such intensity (excluding Yucatan landfalls)?

[kevin]

Even with only 24 hours to go, HMON is not backing down. 961 mbar, 117 kt MH landfall. If that verifies it would be the most significant non-Yucatan Atlantic landfall for Mexico in quite some time right? Which storm (if any) has ever made landfall on the Atlantic side of Mexico with such intensity (excluding Yucatan landfalls)?

https://i.imgur.com/Vor5sAA.png

Decided to do some research and the following major hurricanes fit this description. So Grace could be the most intense hurricane to make landfall on this side of Mexico since Karl in 2010 or even Emily in 2005.

2010 - Karl - Category 3 landfall (976 mb, 100 kt)
2005 - Emily - Category 3 landfall (944 mb, 110 kt)
1988 - Gilbert - Category 3 landfall (955 mb, 110 kt)
1977 - Anita - Category 5 landfall (926 mb, 150 kt)
1966 - Inez - Category 3 landfall (961 mb, 105 kt)
1955 - Hilda - Category 3 landfall (952 mb, 105 kt)
1951 - Charlie - Category 3 landfall (968 mb, 100 kt)
1880 - #2 - Category 4 landfall (931 mb, 130 kt)

[BobHarlem]

The one time it gets it right...
 https://twitter.com/webberweather/status/1428792792214609924

[aspen]

Say what you want about the HWRF this year, but it actually did very well with Grace in the last 3 days before landfall in Veracruz. It corrected forecast Grace:
—developing a tiny core after Jamaica
—staying as a Cat 1 in the WCar
—emerging off of the Yucatán as a rather anemic storm
—quickly becoming very convectively active by Friday morning
—undergoing significant RI into a Cat 3 in the final 12 hours before landfall

I think one run even got Grace’s peak intensity right: 110 kt with a pressure in the low 960s.