Cat 4 Idalia | peak 130mph 940mb | post-tropical (but wait)

[StretchCT]

Euro has been on this one for days, joined by the CMC, Ukie, ICON and  then JMA somewhat yesterday.  GFS jumped on this heavily today.  Hold out NAVGEM also on board.  So with all the globals on board, and less than 4 days to impact, time to open a thread. 

Not a ton of hurricane models on it since it's newly invested.

But this is what it's birth looks like.  I can look at this for an hour and guess where the circulation is.  Pretty broad right now.  And roiling.  You can definitely make out clouds moving east, west and north.  What is more challenging is clouds moving south.  Some over the Yucatan.  And there might be multiple vortices under all that too to make it more difficult.  I think one of the challenges for this storm will be in and where it forms.  A solid low isn't forecast to form until Monday-Monday night and its landfall is Wed morning.  Not a lot of time. 

Some of the possible landfalls, all west coast Florida. After that it's not done, but I'll leave that to the future. 

  

NAM has it too -

 officially 80%

Edited August 31, 2023 by StretchCT

[StretchCT]

Looking at the Euro for shear forecasts.  It's in the skew on the right side.  Levi does us a good and color codes it!  You can see it gets pretty light when over the 90 degree water. 

[1816]

2 hours ago, StretchCT said:

Euro has been on this one for days, joined by the CMC, Ukie, ICON and  then JMA somewhat yesterday.  GFS jumped on this heavily today.  Hold out NAVGEM also on board.  So with all the globals on board, and less than 4 days to impact, time to open a thread. 

Not a ton of hurricane models on it since it's newly invested.

But this is what it's birth looks like.  I can look at this for an hour and guess where the circulation is.  Pretty broad right now.  And roiling.  You can definitely make out clouds moving east, west and north.  What is more challenging is clouds moving south.  Some over the Yucatan.  And there might be multiple vortices under all that too to make it more difficult.  I think one of the challenges for this storm will be in and where it forms.  A solid low isn't forecast to form until Monday-Monday night and its landfall is Wed morning.  Not a lot of time. 

8

Some of the possible landfalls, all west coast Florida. After that it's not done, but I'll leave that to the future. 

  

NAM has it too -

 officially 80%

I'm gonna go with 19.5N, 86.5W

[1816]

2 hours ago, StretchCT said:

Euro has been on this one for days, joined by the CMC, Ukie, ICON and  then JMA somewhat yesterday.  GFS jumped on this heavily today.  Hold out NAVGEM also on board.  So with all the globals on board, and less than 4 days to impact, time to open a thread. 

Not a ton of hurricane models on it since it's newly invested.

But this is what it's birth looks like.  I can look at this for an hour and guess where the circulation is.  Pretty broad right now.  And roiling.  You can definitely make out clouds moving east, west and north.  What is more challenging is clouds moving south.  Some over the Yucatan.  And there might be multiple vortices under all that too to make it more difficult.  I think one of the challenges for this storm will be in and where it forms.  A solid low isn't forecast to form until Monday-Monday night and its landfall is Wed morning.  Not a lot of time. 

Some of the possible landfalls, all west coast Florida. After that it's not done, but I'll leave that to the future. 

  

NAM has it too -

 officially 80%

It's coming here to rain alot probably 

[StretchCT]

soon be a depression

https://x.com/tropicaltidbits/status/1695468850463330551?s=46&t=IUb_brFy2EI-khwn_GJiMA

Edited August 26, 2023 by StretchCT

[StretchCT]

Yeah, this looks pretty convincing as a depression

Radar at https://smn.conagua.gob.mx/es/observando-el-tiempo/radares-meteorologicos-separador/visor-radares-v3

[StretchCT]

Advisories likely this afternoon.

[StretchCT]

12z hurricane models going nuts now on this.

HAFS A 120mph landfall 

HWRF not to landfall yet in run but already 115mph

HAFS B at 140mph for landfall

HMON still playing it cool

[1816]

33 minutes ago, StretchCT said:

12z hurricane models going nuts now on this.

HAFS A 120mph landfall 

HWRF not to landfall yet in run but already 115mph

HAFS B at 140mph for landfall

HMON still playing it cool

Not terribly surprising when the water is hot enough to make soup

[TLChip]

Going to get interesting over the next few days.

 

HWRF

HAFS-A

 

HAFS-B

GFS

Euro

[StretchCT]

TD Ten is born

4:00 PM CDT Sat Aug 26
Location: 21.1°N 86.1°W
Moving: Stationary
Min pressure: 1006 mb
Max sustained: 30 mph

----------------------
At 400 PM CDT (2100 UTC), the center of Tropical Depression Ten was
located near latitude 21.1 North, longitude 86.2 West. The
depression is nearly stationary, and little overall movement is
expected through Sunday.  A slow, generally northward, motion is
expected to begin on Monday.  On the forecast track, the center
will move into the southeastern Gulf of Mexico by Monday.

Maximum sustained winds are near 30 mph (45 km/h) with higher gusts.
Gradual strengthening is forecast during the next 48 hours, and the
system is likely to become a tropical storm on Sunday.

The estimated minimum central pressure is 1006 mb (29.71 inches).

Edited August 26, 2023 by StretchCT

[StretchCT]

Looking at the 200mb winds, they are cutting across the Gulf causing a shear zone to the north of the system.  But those winds eventually go to southerlies which are then moving with the storm by the time the storm gets there.   There's a trough moving in on Monday that somewhat causes that, and creates a place for the system to go.  

The skew loop illustrates the dropping of the shear as that upper low opens up and the trough pushes in.  I love this feature on TT.  Can't believe I never used it before.  Even has the RH image too

 

[StretchCT]

TS Idalia is born.  Looks like the center is exposed on the satellite

1015 AM CDT Sun Aug 27 2023


...DEPRESSION STRENGTHENS TO A TROPICAL STORM...

Observations from a NOAA Hurricane Hunter aircraft indicate that 
Tropical Depression Ten has strengthened into Tropical Storm Idalia.
The maximum winds are estimated to be 40 mph (65 km/h) with higher
gusts.

SUMMARY OF 1015 AM CDT...1515 UTC...INFORMATION
---------------------------------------------------
LOCATION...19.9N 85.8W
ABOUT 80 MI...135 KM ESE OF COZUMEL MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...E OR 90 DEGREES AT 2 MPH...4 KM/H
MINIMUM CENTRAL PRESSURE...996 MB...29.41 INCHES

 

FORECAST POSITIONS AND MAX WINDS

INIT  27/1500Z 19.9N  85.8W   30 KT  35 MPH
 12H  28/0000Z 19.7N  85.9W   40 KT  45 MPH
 24H  28/1200Z 20.6N  85.7W   45 KT  50 MPH
 36H  29/0000Z 21.9N  85.5W   50 KT  60 MPH
 48H  29/1200Z 24.0N  85.2W   60 KT  70 MPH
 60H  30/0000Z 26.2N  85.0W   75 KT  85 MPH
 72H  30/1200Z 28.9N  84.0W   80 KT  90 MPH
 96H  31/1200Z 33.0N  79.5W   45 KT  50 MPH...INLAND
120H  01/1200Z 34.5N  74.0W   45 KT  50 MPH...OVER WATER

$$
Forecaster Pasch

Edited August 27, 2023 by StretchCT

[StretchCT]

Intensity models not impressed.  Most keep it a TS/low end cat 1.

HAFS b is the only one near 100kts

 Tracks seems more locked in

Edited August 27, 2023 by StretchCT

[StretchCT]

Forward speed probably saves the Gulf coast somewhat. Lateral to Cuba to inland in 32 hrs.  It's moving 540 miles in that time frame, so about 16-17mph. 

 

[Grace]

NAM 3km....always does this comical stuff. So here ya go:

 

[StretchCT]

As we say good night to Idalia, the convection seems to be blowing up over the center.

[StretchCT]

Idalia now forecast to hit 100mph before landfall

INIT  27/2100Z 20.1N  85.5W   35 KT  40 MPH
 12H  28/0600Z 20.5N  85.3W   45 KT  50 MPH
 24H  28/1800Z 21.7N  85.0W   55 KT  65 MPH
 36H  29/0600Z 23.4N  84.9W   65 KT  75 MPH
 48H  29/1800Z 25.6N  84.5W   75 KT  85 MPH
 60H  30/0600Z 28.7N  83.7W   85 KT 100 MPH
 72H  30/1800Z 31.3N  81.9W   50 KT  60 MPH...INLAND
 96H  31/1800Z 34.5N  76.0W   50 KT  60 MPH...OVER WATER
120H  01/1800Z 35.0N  71.0W   55 KT  65 MPH

Prior forecasts in spoiler, most recent first - 90, 90, 80, 75

Spoiler

 
INIT  27/1500Z 19.9N  85.8W   30 KT  35 MPH
 12H  28/0000Z 19.7N  85.9W   40 KT  45 MPH
 24H  28/1200Z 20.6N  85.7W   45 KT  50 MPH
 36H  29/0000Z 21.9N  85.5W   50 KT  60 MPH
 48H  29/1200Z 24.0N  85.2W   60 KT  70 MPH
 60H  30/0000Z 26.2N  85.0W   75 KT  85 MPH
 72H  30/1200Z 28.9N  84.0W   80 KT  90 MPH
 96H  31/1200Z 33.0N  79.5W   45 KT  50 MPH...INLAND
120H  01/1200Z 34.5N  74.0W   45 KT  50 MPH...OVER WATER

 

INIT  27/0900Z 20.1N  86.8W   30 KT  35 MPH
 12H  27/1800Z 20.1N  86.5W   40 KT  45 MPH
 24H  28/0600Z 20.6N  86.3W   45 KT  50 MPH
 36H  28/1800Z 21.7N  86.3W   50 KT  60 MPH
 48H  29/0600Z 23.3N  86.2W   60 KT  70 MPH
 60H  29/1800Z 25.7N  85.7W   75 KT  85 MPH
 72H  30/0600Z 28.5N  84.7W   80 KT  90 MPH
 96H  31/0600Z 33.0N  81.2W   45 KT  50 MPH...INLAND
120H  01/0600Z 35.0N  75.5W   35 KT  40 MPH...OVER WATER
 

INIT  27/0300Z 21.1N  86.4W   30 KT  35 MPH
 12H  27/1200Z 20.9N  86.4W   35 KT  40 MPH
 24H  28/0000Z 20.9N  86.2W   40 KT  45 MPH
 36H  28/1200Z 21.6N  85.9W   45 KT  50 MPH
 48H  29/0000Z 23.1N  85.7W   55 KT  65 MPH
 60H  29/1200Z 25.0N  85.5W   65 KT  75 MPH
 72H  30/0000Z 27.5N  84.8W   70 KT  80 MPH
 96H  31/0000Z 32.7N  81.5W   45 KT  50 MPH...INLAND
120H  01/0000Z 35.2N  76.7W   35 KT  40 MPH...INLAND
 

INIT  26/2100Z 21.1N  86.1W   25 KT  30 MPH
 12H  27/0600Z 21.0N  86.3W   30 KT  35 MPH
 24H  27/1800Z 20.9N  86.2W   35 KT  40 MPH
 36H  28/0600Z 20.8N  86.1W   40 KT  45 MPH
 48H  28/1800Z 22.0N  85.7W   45 KT  50 MPH
 60H  29/0600Z 24.0N  85.6W   50 KT  60 MPH
 72H  29/1800Z 26.3N  85.3W   65 KT  75 MPH
 96H  30/1800Z 31.5N  83.0W   45 KT  50 MPH...INLAND
120H  31/1800Z 35.0N  79.0W   30 KT  35 MPH...INLAND

 

[StretchCT]

This buoy is SE of Idalia 

https://www.ndbc.noaa.gov/station_page.php?station=42056

[StretchCT]

Didn't expect an interim

7:00 PM CDT Sun Aug 27
Location: 20.1°N 85.4°W
Moving: ENE at 3 mph
Min pressure: 995 mb
Max sustained: 45 mph
 

[DJKuo]

6 hours ago, Grace said:

NAM 3km....always does this comical stuff. So here ya go:

 

FWIW, I remember the NAM 3km wasn’t too far off with Michael’s forecast intensity. Obviously anything sub 910mb is probably fantasy. 

[DJKuo]

Looking like the center of circulation has jogged south again. This entails 2 things: 1) it means the circulation is adjusting and getting better stacked. 2) any further south movements inevitably means a sooner east turn later in the forecast which means watch out Tampa. 

https://x.com/wxreboot/status/1695960729319325917?s=61

 

[StretchCT]

1 hour ago, StretchCT said:

This buoy is SE of Idalia 

https://www.ndbc.noaa.gov/station_page.php?station=42056

This was 1003.3 at noon edt. 997 now. And it's SE of the storm. 

[Sentinel]

7 hours ago, Grace said:

NAM 3km....always does this comical stuff. So here ya go:

 

 

1 hour ago, DJKuo said:

FWIW, I remember the NAM 3km wasn’t too far off with Michael’s forecast intensity. Obviously anything sub 910mb is probably fantasy. 

I won't go with 896mb... But I believe this will be a major at LF. The water is rocket fuel right now for this storm and the trough set up will likely provide some  favorable interaction; ie venting. This actually has my soidy senses pretty concerned. 

[1816]

25 minutes ago, Uscg Ast said:

 

I won't go with 896mb... But I believe this will be a major at LF. The water is rocket fuel right now for this storm and the trough set up will likely provide some  favorable interaction; ie venting. This actually has my soidy senses pretty concerned. 

These hurricane intensity forecasts are like snowfall forecasts with the models. When the snow totals on all the models starts swinging toward the big outlier you know something serious is cooking. If the other models start increasing the intensity every run watch out. But yeah that whole gulf is just a big hot tub right now.