Hurricane Idalia

[WxWatcher007]

 

[hawkeye_wx]

Oddly, the GFS drops the 500 mb vorticity southward, but keeps the weak surface low stationary, off the northeast tip of the Yucatan.

[hawkeye_wx]

This system really lost its core convection this afternoon.

[Eskimo Joe]

 

 

[Nibor]

 

Satellite doesn't look as great but there still seems to be decent core rotation based on radar.

[CheeselandSkies]

HAFS-A is at 956 MB just offshore, at FH078. Next frame, at FH081, is at 954 MB well inland.

[MattPetrulli]

1 hour ago, hawkeye_wx said:

This system really lost its core convection this afternoon.

 

18 minutes ago, Nibor said:

 

Satellite doesn't look as great but there still seems to be decent core rotation based on radar.

It's diurnal minimum, it isn't surprising or anything. Not saying you guys are saying it's surprising, I'm just stating that fact.

[Floydbuster]

Evening video update on TD-10
https://www.youtube.com/watch?v=e9xzL_UNJHQ

[WxSynopsisDavid]

12 minutes ago, MattPetrulli said:

 

It's diurnal minimum, it isn't surprising or anything. Not saying you guys are saying it's surprising, I'm just stating that fact.

Diurnal minimum is correct, this is typically when we see tropical systems lose that photogenic appearance. Big thing here is that during the day the centers of circulation are starting to organize. We are starting to see this system get a tad more symmetrical and some noticeable spin. What we ultimately are waiting for is the low, mid, and upper level circulations to stack. Once this thing starts to ventilate than we will have a better grasp on this system. Big thing everyone should be paying attention to is the environment out ahead of this system. With a lack of dry air and decreasing shear, it sets up a near pristine environment over 90+ degree SST's. There are some noticeable warm eddies in the Gulf too, not to mention how warm the Gulf Loop Current is right now. There are a lot of factors in play working for this thing to take off vs hindering it. 

With that said, recon data will be vital tomorrow. I'm curious to know if indeed we get an anticyclone development and I'm also curious to know if Recon Hunters find that shear and dry air are more significant than what models are showing.

[cptcatz]

HAFS with a potentially catastrophic surge into Tampa Bay...

[WxSynopsisDavid]

5 minutes ago, cptcatz said:

HAFS with a potentially catastrophic surge into Tampa Bay...

Angle of approach is concerning, that would be a strengthening Category 3 approaching landfall. Frictional induced intensification through landfall.

[cptcatz]

8 minutes ago, WxSynopsisDavid said:

Angle of approach is concerning, that would be a strengthening Category 3 approaching landfall. Frictional induced intensification through landfall.

Yeah I mean getting Tampa Bay directly on the south side of a major hurricane is like a needle in a haystack, but if it were to actually happen here, I think a lot of people would brush off the warnings after what happened with Ian less than a year ago. 

[MattPetrulli]

Oh

[Prospero]

15 minutes ago, cptcatz said:

Yeah I mean getting Tampa Bay directly on the south side of a major hurricane is like a needle in a haystack, but if it were to actually happen here, I think a lot of people would brush off the warnings after what happened with Ian less than a year ago. 

I ordered a mix of batteries (D, AA, 9volt, etc.) and a couple basic supplies from Sam's Club when I woke up this morning and they were delivered by mid-afternoon. Sure beats the old days of driving down, parking and hiking across a vast hot parking lot, and being in the aggressive panicking crowds.

But it was not as fun as the old chaos where you could get beat up for grabbing the last pack of D batteries...

 

[Windspeed]

Oh

Yeah, Cowan just noted the tighter core. It's a little anemic on the convective side at the moment, but it does still appear to be organizing. New convective bursts would aid that process. Additionally, convection that was focused east and south of Cuba is getting further away. This may also aid in easing any negative influences and subsidence working against the COC. That being said, it is drifting very close to the Rivera Maya coastline. If it remains offshore, the TC may ramp up on Sunday. If it meanders inland, obviously, that will delay the intensification process. Of course, that is very much what the Globals had been doing for quite a number of OP runs since yesterday.

[WxSynopsisDavid]

Looking at the shear values in the environment around TD 10, there's are a noticeable decrease in shear. Earlier today, the system was completely shrouded in 40kt shear. Now this evening, we see a big time decrease in shear to the northeast and some relaxation to the north. Not a good trend because this falls right in-line with those hurricane models earlier today. They seem to indicate the relaxation of shear this evening/overnight and better organization and development tomorrow. 

[WxWatcher007]

You can see on that graphic that it’s still working under the influence of the ULAC. That’s been key to development given the shear in the region. It’s basically working in a pristine TC genesis environment currently—and land is the only thing that could be reasonably expected to slow this down before it lifts into the Gulf.

[Prospero]

Here in Tampa Bay we who are experienced are preparing a little. Gulfport Florida has been so lucky for too many years. There is a physical reason why we don't get nailed like the panhandle, but it we are still vulnerable even if not as often as the northern Gulf of Mexico.

Storm mode on:

https://thegabber.com/what-you-need-to-know-about-td-10-in-gulfport-st-pete/

 

[Kevin Reilly]

2 hours ago, Nibor said:

 

Satellite doesn't look as great but there still seems to be decent core rotation based on radar.

At first almost looks like there are multiple circulations but at the end of the loop clearly can see one dominant low-pressure system take over and move actually SSW towards Cozumel in Mexico.

[WxSynopsisDavid]

15 minutes ago, WxWatcher007 said:

You can see on that graphic that it’s still working under the influence of the ULAC. That’s been key to development given the shear in the region. It’s basically working in a pristine TC genesis environment currently—and land is the only thing that could be reasonably expected to slow this down before it lifts into the Gulf.

Agreed, and it is not good that as forecasters we have no limiting factors in play here to discuss. It's come down to how long it lingers near the Yucatan....really feels like dejavu from some of the previous big gulf storms we have forecasted.

[cptcatz]

FYI here is the link to the radar Brian used: https://smn.conagua.gob.mx/es/observando-el-tiempo/radares-meteorologicos-separador/visor-radares-v3

Still looks like it's moving almost due south (maybe just a tad west of due south).  Unless it makes a harder turn west, it should continue to stay off shore.

[yoda]

 

 

[Prospero]

20 minutes ago, yoda said:

 

 

That puts us (Tampa Bay) on the surge side. Still, its likely the path will change every day. But they are getting much better last few years.

[Windspeed]

It's interesting that both 18z HAFS TC models lose the vorticity somewhat over the next 24 hours. It then comes back on both and rapidly reorganizes from 36-48 hours, and shortly afterward, lifts NNE as a hurricane. I don't know if this is simulated proximity to the Rivera Maya coast or some other atmospheric influence occurring. But it is odd at the breakdown, then rapid ramp up on that TC blend in such a short period of time.

[yoda]

BULLETIN
Tropical Depression Ten Advisory Number   2
NWS National Hurricane Center Miami FL       AL102023
1000 PM CDT Sat Aug 26 2023

...DEPRESSION EXPECTED TO BECOME A TROPICAL STORM ON SUNDAY...
...LIKELY TO BECOME A HURRICANE OVER THE EASTERN GULF OF MEXICO IN
A FEW DAYS...


SUMMARY OF 1000 PM CDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.1N 86.4W
ABOUT 55 MI...85 KM NE OF COZUMEL MEXICO
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...SW OR 230 DEGREES AT 2 MPH...4 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The government of Cuba has upgraded the Tropical Storm Watch for
Pinar del Rio to a Tropical Storm Warning.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Yucatan Peninsula from Tulum to Rio Lagartos, including Cozumel
* Pinar del Rio Cuba

A Tropical Storm Watch is in effect for...
* Isle of Youth Cuba

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

Interests in Florida should monitor the progress of this system.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 1000 PM CDT (0300 UTC), the center of Tropical Depression Ten was
located near latitude 21.1 North, longitude 86.4 West.  The
depression is drifting toward the southwest near 2 mph (4 km/h) and 
is likely to meander near the Yucatan Channel through early Monday. 
A faster motion toward the north or north-northeast is expected on 
Monday, bringing the system over the eastern Gulf of Mexico.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Additional strengthening is forecast during the next few days.  The 
depression is expected to become a tropical storm on Sunday and a 
hurricane by Tuesday.

The estimated minimum central pressure is 1005 mb (29.68 inches).

[yoda]

 

000
WTNT45 KNHC 270244
TCDAT5

Tropical Depression Ten Discussion Number   2
NWS National Hurricane Center Miami FL       AL102023
1000 PM CDT Sat Aug 26 2023

Images from the Mexico meteorological service's radar in Cancun show 
that the depression has a small but well-defined circulation with 
spiral banding extending no more than about 60 n mi from the center. 
 This feature is embedded within a larger circulation with scattered 
deep convection covering the northwestern Caribbean Sea, extreme 
southeastern Gulf of Mexico, and adjacent land areas.  The initial 
intensity is set to 30 kt based on the latest subjective Dvorak 
estimate from TAFB and objective numbers from UW-CIMSS.

The depression appears to be drifting toward the southwest with an 
initial motion of 230/2 kt, with low- to mid-level ridging located 
to its north and northwest.  The system is expected to continue 
meandering over the northwestern Caribbean Sea for the next 24-36 
hours.  After that time, a developing trough over the Gulf of Mexico 
and strengthening ridging over the western Atlantic is expected to 
begin lifting the system toward the north and north-northeast over 
the eastern Gulf of Mexico toward Florida, and then near the 
southeastern coast of the U.S.  The updated NHC track forecast lies 
on top of or very near the previous prediction and closely follows 
the TVCX and HCCA consensus aids.  

Assuming the depression's center does not move over the Yucatan 
Peninsula, very warm waters and low to moderate vertical shear 
should support gradual strengthening during the next few days.  The 
NHC intensity prediction is a little below the consensus aids during 
the first 36 hours of the forecast but then converges with those 
aids thereafter, showing the system reaching hurricane strength by 
60 hours.  The system is expected to remain a hurricane, and 
potentially continue strengthening, up until it reaches the Gulf 
coast of Florida on Wednesday.  Users are reminded to continue 
monitoring forecasts for any changes to the system's expected 
intensity as it approaches Florida.  Land interaction and increasing 
shear should lead to fast weakening after the system moves over 
land, but it could still produce tropical-storm-force winds near and 
offshore the southeastern coast of the U.S. even if the center is 
inland.


KEY MESSAGES:

1. Heavy rainfall from Tropical Depression Ten is expected across
the eastern Yucatan Peninsula and western Cuba. The heavy rainfall
may produce areas of flash and urban flooding, as well as
landslides, across western Cuba.  The depression is forecast to
become a tropical storm by Sunday, and tropical storm conditions are
expected over portions of the Yucatan Peninsula and extreme 
western Cuba where a Tropical Storm Warning is in effect.  Tropical 
storm conditions are possible on the Isle of Youth, where a Tropical 
Storm Watch is in effect.

2. The depression is forecast to strengthen during the next few days
and could become a hurricane over the eastern Gulf of Mexico,
bringing a potential of dangerous storm surge, heavy rainfall, and
strong winds to portions of the west coast of Florida and the
Florida Panhandle by the middle of next week.  Heavy rainfall is
also likely to spread into portions of the Southeast U.S. by mid to
late next week.  Although it is too soon to specify the exact
location and magnitude of these impacts, residents in these areas
should monitor updates to the forecast of this system and ensure
that they have their hurricane plan in place.


FORECAST POSITIONS AND MAX WINDS

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

$$
Forecaster Berg

[yoda]

 

[MattPetrulli]

Something of note, this region doesn't get significant hurricane hits often at all (big bend area of FL). That being said, one of the last direct big hits was Hurricane Hermine which landfalled at 80 MPH as a slightly above averaged size storm. It produced a damaging 6-9 ft surge in that region and was locally quite destructive. It's likely we get >80 MPH at landfall if this were to landfall in the same region. Also may be the same size if not a little bigger than Hermine. That would be a much higher surge than what Hermine did in a very surge suspectable region. Also, this area is the most impoverished part of Florida. As a result, the building codes are some of the weakest in the state. Yes, this is a somewhat sparsely populated area compared to other places in FL, but its a much weaker area in general. So it's a bit of a concerning pick your poison scenario.

[Normandy]

Evening thoughts remain unchanged from yesterday.  The mean cyclonic center of the storm is sufficiently off the coast that I think steady deepening will occur over tomorrow as it meanders near the Yucatan. I can easily see a strong TS approaching hurricane status before it turns northward.

Once it turns north, you have an excellent setup for a major hurricane strike:  deep ULL to the west and high to the east, with a poleward jet developing on approach to the coast.  While the ingredients are not identical, there are several hurricanes with this type of setup that have deepened upon approach to the gulf coast / FL peninsula.  Still like my call of a major into the area just north of Tampa.

[Nibor]

A little hard to tell but it looks like circulation will come very close or over Cozumel.