Hurricane Idalia

[yoda]

Tropical Storm Idalia Advisory Number   8
NWS National Hurricane Center Miami FL       AL102023
1000 AM CDT Mon Aug 28 2023

...STORM SURGE AND HURRICANE WARNINGS ISSUED FOR PORTIONS OF THE
WEST COAST OF FLORIDA...
...LIFE-THREATENING STORM SURGE AND DANGEROUS WINDS BECOMING
INCREASINGLY LIKELY FOR PORTIONS OF FLORIDA...


SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...20.8N 85.2W
ABOUT 80 MI...125 KM SSW OF THE WESTERN TIP OF CUBA
ABOUT 305 MI...495 KM SSW OF THE DRY TORTUGAS
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...990 MB...29.24 INCHES


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

A Storm Surge Warning has been issued from Englewood northward to
the Ochlockonee River, including Tampa Bay.

A Hurricane Warning has been issued from the Middle of Longboat Key
northward to the Holocene River, including Tampa Bay.

A Tropical Storm Warning has been issued from Chokoloskee northward
to the Middle of Longboat Key, and from west of the Lockheed
River westward to Indian Pass.

A Storm Surge Watch has been issued from Mouth of the St. Mary's
River to Altamaha Sound, Georgia.

A Tropical Storm Watch has been issued for the Atlantic coast of
Florida and Georgia from Sebastian Inlet, Florida northward to
Altamaha Sound, Georgia.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* Englewood northward to the Ochlockonee River, including Tampa Bay

A Hurricane Warning is in effect for...
* Cuban province of Pinar del Rio
* Middle of Longboat Key northward to the Ochlockonee River,
including Tampa Bay

A Tropical Storm Warning is in effect for...
* Yucatan Peninsula from Tulum to Rio Lagartos, including Cozumel
* Isle of Youth Cuba
* Dry Tortugas Florida
* Chokoloskee northward to the Middle of Longboat Key
* West of the Ochlockonee River westward to Indian Pass

A Storm Surge Watch is in effect for...
* Chokoloskee northward to Englewood, including Charlotte Harbour
* Ochlockonee River to Indian Pass Florida
* Mouth of the St. Mary's River to Altamaha Sound Georgia

A Hurricane Watch is in effect for...
* Englewood to the Middle of Longboat Key
* West of the Ochlockonee River westward to Indian Pass

A Tropical Storm Warning is in effect for...
* South of the Middle of Longboat Key to Chokoloskee Florida
* West of the Ochlockonee River westward to Indian Pass

A Tropical Storm Watch is in effect for...
* Lower Florida Keys west of the west end of the Seven Mile Bridge
* Sebastian Inlet Florida northward to Altamaha Sound Georgia

A Hurricane Warning means that hurricane conditions are expected 
somewhere within the warning area.  A warning is typically issued 36 
hours before the anticipated first occurrence of 
tropical-storm-force winds, conditions that make outside 
preparations difficult or dangerous.  Preparations to protect life 
and property should be rushed to completion.A Hurricane Warning 
means that hurricane conditions are expected somewhere within the 
warning area, in this case within the next 12-24 hours.  
Preparations to protect life and property should be rushed to 
completion.

A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.

A Hurricane Watch means that hurricane conditions are possible
within the watch area.

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

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

Interests along the southeastern U.S. coast should monitor the
progress of this system.  Additional watches and warnings will
likely be required later today.

For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 1000 AM CDT (1500 UTC), the center of Tropical Storm Idalia was
located near latitude 20.8 North, longitude 85.2 West. Idalia is
moving toward the north near 8 mph (13 km/h). A northward motion
is expected through tonight, followed by a faster north-northeast
motion on Tuesday and Wednesday.  On the forecast track, the center
of Idalia is forecast to pass near or over western Cuba tonight,
over the extreme southeastern Gulf of Mexico by early Tuesday, and
reach the Gulf coast of Florida on Wednesday.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts.   Idalia is forecast to become a hurricane later today and a
dangerous major hurricane over the northeastern Gulf of Mexico by
early Wednesday.

Tropical-storm-force winds extend outward up to 105 miles (165 km)
from the center.

The latest minimum central pressure estimated from data from an Air
Force Reserve reconnaissance aircraft is 990 mb (29.24 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Idalia can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT5 and WMO header WTNT45 KNHC,
and on the web at hurricanes.gov/text/MIATCDAT5.shtml

STORM SURGE:  The combination of a dangerous storm surge and the
tide will cause normally dry areas near the coast to be flooded by
rising waters moving inland from the shoreline.  The water could
reach the following heights above ground somewhere in the indicated
areas if the peak surge occurs at the time of high tide...

Aucilla River, FL to Chassahowitzka, FL...7-11 ft
Chassahowitzka, FL to Anclote River, FL...6-9 ft
Ochlockonee River, FL to Aucilla River, FL...4-7 ft
Anclote River, FL to Middle of Longboat Key, FL...4-7 ft
Tampa Bay...4-7 ft
Middle of Longboat Key, FL to Englewood, FL...3-5 ft
Englewood, FL to Chokoloskee, FL...2-4 ft
Charlotte Harbor...2-4 ft
Indian Pass, FL to Ochlockonee River, FL...2-4 ft
Mouth of the St. Mary's River to Altamaha Sound, GA...2-4 ft
Chokoloskee, FL to East Cape Sable, FL...1-3 ft
Flagler/Volusia County Line, FL to Mouth of the St. Mary's 
River...1-3 ft
Florida Keys...1-2 ft

The deepest water will occur along the immediate coast in areas of
onshore winds, where the surge will be accompanied by large and
dangerous waves.  Surge-related flooding depends on the relative
timing of the surge and the tidal cycle, and can vary greatly over
short distances. For information specific to your area, please see
products issued by your local National Weather Service forecast
office.

Storm surge will raise water levels by as much as 4 to 6 feet above
normal tide levels along the southern coast of Pinar del Rio, Cuba.
Near the coast, the surge will be accompanied by large waves.

WIND:  Hurricane conditions are expected within the hurricane
warning area in western Cuba later today.  Winds are expected to
first reach tropical storm strength by this morning, making
outside preparations difficult or dangerous.  Preparations to
protect life and property should be rushed to completion.

Tropical storm conditions are expected over portions of the
tropical storm warning area over the Yucatan Peninsula and the Isle
of Youth in Cuba through today

Hurricane conditions are expected within the hurricane warning area 
in Florida by late Tuesday or Wednesday, with tropical storm 
conditions beginning on Tuesday.

Tropical storm conditions are expected in the Dry Tortugas 
beginning late today and within the tropical storm warning area 
along the Florida Gulf coast on Tuesday.

RAINFALL:  Idalia is expected to produce the following rainfall 
amounts:

Portions of the eastern Yucatan: Additional 1 to 2 inches.

Western Cuba: 4 to 7 inches, with isolated higher totals of 10 
inches.

Portions of the west coast of Florida, the Florida Panhandle, 
southeast Georgia and the eastern Carolinas: 4 to 8 inches from 
Tuesday into Thursday. Isolated higher totals of 12 inches possible, 
primarily near landfall in northern Florida.

This rainfall may lead to flash and urban flooding, and landslides 
across western Cuba. 

Areas of flash and urban flooding, some of which may be locally 
significant, are expected across portions of the west coast of 
Florida, the Florida Panhandle, and southern Georgia Tuesday into 
Wednesday, spreading into portions of the eastern Carolinas 
Wednesday into Thursday.

SURF:  Swells generated by Idalia are affecting portions of the
southern coast of Cuba and eastern Yucatan.  These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.

TORNADO: A few tornadoes will be possible starting Tuesday along the 
west central Florida coast and the tornado threat will spread 
northward into the Florida Big Bend area by Tuesday night.

NEXT ADVISORY
-------------
Next intermediate advisory at 100 PM CDT.
Next complete advisory at 400 PM CDT.

$$
Forecaster Brown

[yoda]

Hurricane Warning up for Tampa Bay proper

[yoda]

Tropical Storm Idalia Discussion Number   8
NWS National Hurricane Center Miami FL       AL102023
1000 AM CDT Mon Aug 28 2023

The satellite presentation of the storm has improved this morning
with the center more deeply embedded within the deep convection and
colder cloud tops.  However, recent reconnaissance aircraft data
from both the U.S. Air Force Reserve and NOAA indicate that the
improved satellite presentation has not yet resulted in an
increase in wind speed.  The Air Force Hurricane Hunter aircraft
has measured peak 850-mb flight-level winds of 68 kt, and a minimum
pressure around 990 mb.  Based on these data, the initial intensity
remains 55 kt this advisory.  The Air Force aircraft will be in the
storm environment through early afternoon and that data should
continue to provide information Idalia's structure and intensity.

Recent satellite and aircraft fixes show that Idalia is moving
northward or 360/8 kt.  A mid-level trough over the central
Gulf of Mexico and a ridge near the Greater Antilles should cause
Idalia to move northward at a faster forward speed during the next
12-24 hours.  After that time, an even faster north-northeast
motion is expected an another mid-level trough moves across the
central and eastern portions of the United States.  The latest NHC
track forecast is again quite similar to the previous forecast.
Although the track forecast has been quite consistent, there is
still some spread in the guidance by 48 hours, and it cannot be
emphasized enough that only a small deviation in the track could
cause a significant change in Idalia's landfall location in Florida
due to the paralleling track to the west coast of the state.

Although there is still some moderate northwesterly over the storm,
intensification seems likely during the next 12-18 hours, and
Idalia is forecast to become a hurricane during that time.  By
Tuesday, the environment over the eastern Gulf of Mexico is
expected to become more conducive for strengthening.  Steady to
rapid intensification is predicted beginning Tuesday while Idalia
traverses the warm waters of the eastern Gulf and the upper-level
environment becomes more favorable.  The NHC intensity forecast
again calls for Idalia to reach major hurricane strength before
landfall along the Gulf coast of Florida.

This forecast has necessitated the issuance of Storm Surge and
Hurricane Warnings for portions of the west coast of Florida and
Storm Surge and Tropical Storm Watches for portions of the Atlantic
coasts of Florida and Georgia.

KEY MESSAGES:

1. There is a danger of life-threatening storm surge inundation 
along portions of the Florida Gulf Coast where a Storm Surge Warning 
is in effect, including Tampa Bay and the Big Bend region of 
Florida. Inundation of 7 to 11 feet above ground level is expected 
somewhere between Chassahowitzka and Aucilla River.  Residents in 
these areas should follow any advice given by local officials. 

2. Hurricane conditions are expected within portions of the 
Hurricane Warning area along the Florida Gulf Coast, with the 
potential for destructive winds where the core of Idalia moves 
onshore. Strong winds will also spread inland across portions of 
northern Florida near the track of the center of Idalia.

3. Areas of flash and urban flooding, some of which may be locally 
significant, are expected across portions of the west coast of 
Florida, the Florida Panhandle, and southern Georgia Tuesday into 
Wednesday, spreading into portions of the eastern Carolinas 
Wednesday into Thursday.

4. Hurricane-force winds are expected across portions of far western 
Cuba later today.  Heavy rainfall is also expected across portions 
of western Cuba and may produce areas of flash and urban 
flooding as well as landslides across western Cuba.

FORECAST POSITIONS AND MAX WINDS

INIT  28/1500Z 20.8N  85.2W   55 KT  65 MPH
 12H  29/0000Z 22.0N  85.2W   65 KT  75 MPH
 24H  29/1200Z 23.9N  85.1W   75 KT  85 MPH
 36H  30/0000Z 26.4N  84.6W   90 KT 105 MPH
 48H  30/1200Z 29.2N  83.5W  100 KT 115 MPH
 60H  31/0000Z 31.9N  81.2W   55 KT  65 MPH...INLAND
 72H  31/1200Z 33.6N  78.0W   50 KT  60 MPH...OVER WATER
 96H  01/1200Z 34.6N  71.2W   50 KT  60 MPH
120H  02/1200Z 34.5N  67.0W   50 KT  60 MPH

$$
Forecaster Brown

[yoda]

 

[dan11295]

NHC now not showing quite as much intensification prior to landfall. the 12z intensity models on Tropical Tidbits have also pulled back a bit, keeping Idalia and strong 2 to weak 3. Of  course RI can be hard to predict, so can't assume anything from that.

[CheeselandSkies]

1 minute ago, dan11295 said:

NHC now not showing quite as much intensification prior to landfall. the 12z intensity models on Tropical Tidbits have also pulled back a bit, keeping Idalia and strong 2 to weak 3. Of  course RI can be hard to predict, so can't assume anything from that.

The 12Z hurricane models aren't actually out yet, and won't be for another few hours.

[CoastalWx]

2 minutes ago, CheeselandSkies said:

The 12Z hurricane models aren't actually out yet, and won't be for another few hours.

Tropical Tidbits has them.

[CheeselandSkies]

3 minutes ago, CoastalWx said:

Tropical Tidbits has them.

Where? All still the 06Z runs for me.

[CoastalWx]

1 minute ago, CheeselandSkies said:

Where? All still the 06Z runs for me.

[MUWX]

1 minute ago, CoastalWx said:

That is not intensity guidance.

[Eskimo Joe]

GFS trying to turn Idalia back into the southeast at HR 168?

[CoastalWx]

1 minute ago, MUWX said:

That is not intensity guidance.

I know that. Just showing that 12z guidance is available.

 

[schoeppeya]

Idalia has had a really hard time actually wrapping feeder bands into the center of the system

[CheeselandSkies]

Just now, CoastalWx said:

I know that. Just showing that 12z guidance is available.

 

I prefer to wait for the actual frame-by-frame model runs of the hurricane models (HAFS-A/B, HWRF, HMON) with MSLP, sim IR, etc.

[dan11295]

Guidance has been consistent or more or less keeping Idalia in check into shear lessen N of Cuba later tonight/early tomorrow.

[CoastalWx]

1 minute ago, CheeselandSkies said:

I prefer to wait for the actual frame-by-frame model runs of the hurricane models (HAFS-A/B, HWRF, HMON) with MSLP, sim IR, etc.

It gives you a good idea though about how things like track and intensity are changing. 

[GaWx]

2 hours ago, Hotair said:

TV reminding folks how far Ian track was from actual LF 72 hours out. I do believe the steering patterns are a little better behaved this time given the multi model consensus, but no one inside the cone should let their guard down  

 

 

 Below is a copy of a post I did 10/1/22 detailing Ian FL LF progs for 5 main op models starting from 0Z 9/25 runs, which were then 85 hours out from the Port Charlotte LF. As of 0Z today, Idalia was only ~60 hours from landfall. So, that would about correspond to the 0Z 9/26 runs for Ian.

 So, one can see from this that:

A. -Top performing UKMET <50 miles from actual Ian LF all runs within 85 hours. ~Spot on for runs that were 85, 61, 49, and 13 hours out with little net bias.

-2nd best ICON even had Tampa (70 miles too far left) just 49 hours out

-CMC was still way too far left just 25 hrs out!

-GFS not close til 25 hrs out

-Euro not close til 37 hrs out

B. Per 0Z 9/26 Ian runs, which correspond to ~how far from LF is Idalia as of 0Z today (~60 hours):

1) UKMET was spot on and ICON only 25 miles too far left

2) CMC and GFS were way up at Apalachee Bay, a whopping 250 miles too far left

3) Euro was up at Cedar Key, 160 miles too far left

4) So, non-UKMET models were all too far left with GFS, CMC, and Euro a whopping 160-250 miles too far left

5) For Idalia, models are way closer together for LF at ~60 hour point (0Z 8/28 runs):

-GFS/CMC furthest left near Perry

-ICON furthest right ~10 miles SE of Cedar Key

-So, range is only 75 miles vs 250 miles for Ian at same time from LF! GFS/CMC are furthest left like for Ian but not nearly by as much

-UKMET/Euro right in middle ~30 miles NW of Cedar Key

-Based on this, I'm guessing that 0Z GFS/CMC at Perry will verify too far left

-My best guess is to go close to 0Z UKMET/Euro, which were ~30 miles NW of Cedar Key and ~40 miles NW of 0Z ICON

 

---------------------------------

Here's the Ian FL landfall model performance post I made last year:

"Looking back to the 0Z 9/25 runs at where the models had FL landfalls:

0Z 9/25:
ICON Venice
CMC Cedar Key
GFS Destin
Euro Sarasota
UKMET Port Charlotte

12Z 9/25:
ICON Sarasota
CMC Apalachee Bay
GFS Apalachee Bay
Euro Tampa
UKMET Venice

0Z 9/26:
ICON Venice
CMC Apalachee Bay
GFS Apalachee Bay
Euro Cedar Key
UKMET Port Charlotte

12Z 9/26:
ICON Tampa
CMC Apalachicola
GFS Tampa
Euro Big Bend
UKMET Port Charlotte

0Z 9/27:
ICON Venice
CMC Big Bend
GFS Sarasota
Euro Venice
UKMET just N of Ft Myers

12Z 9/27:
ICON Port Charlotte
CMC Tampa
GFS just N of Port Charlotte
Euro Port Charlotte
UKMET 20 miles S of Ft. Myers

0Z 9/28:
ICON 15 miles S of Port Charlotte
CMC Venice
GFS Port Charlotte
Euro Port Charlotte
UKMET Port Charlotte

 My grades on FL landfall only (i.e., excluding SC landfall) for 9/25-8 runs:

UKMET A-
ICON B
Euro C-
GFS D
CMC F"

 

 

 

[Prismshine Productions]

Yeah, and notice they ticked back west...

Sent from my SM-S146VL using Tapatalk

[NERMAN]

10 minutes ago, CheeselandSkies said:

I prefer to wait for the actual frame-by-frame model runs of the hurricane models (HAFS-A/B, HWRF, HMON) with MSLP, sim IR, etc.

Totally agree. HWRF showed a strong Cat 4 at 06z and the others had a strong Cat 3. Let's see what they have at 12z before saying the guidance has dropped. 

[Windspeed]

Idalia has had a really hard time actually wrapping feeder bands into the center of the system

There is still mid-level shear imparting the circulation. That being said, the core is showing a favorable environment for continued bursts of deep convection. So it's going to be another 24 hours of give and take as bursts of convection try to wrap up shear east and then north of the center, then likely get blown back and fail to wrap from 700 to 400 hPa levels. I'd imagine this will occur repeatedly as the LLC drives just west of Cuba and into the SE GOM. Mid-level flow values won't become more favorable until well into tonight. That is when we may start seeing more alignment and more pronounced intensification on Tuesday. Eventually, into Wednesday, the flow vector will become more dangerous for significant intensification all the way into landfall, hence modeling and the official forecast.

[SnowGoose69]

3 minutes ago, Windspeed said:

20 minutes ago, schoeppeya said:

Idalia has had a really hard time actually wrapping feeder bands into the center of the system

There is still mid-level shear imparting the circulation. That being said, the core is showing a favorable environment for continued bursts of deep convection. So it's going to be another 24 hours of give and take as bursts of convection try to wrap up shear east and then north of the center, then likely get blown back and fail to wrap from 700 to 400 hPa levels. I'd imagine this will occur repeatedly as the LLC drives just west of Cuba and into the SE GOM. Mid-level flow values won't become more favorable until well into tonight. That is when we may start seeing more alignment and more pronounced intensification on Tuesday. Eventually, into Wednesday, the flow vector will become more dangerous for significant intensification all the way into landfall, hence modeling and the official forecast.

The timing of any intensification may end up not being ideal.   No doubt a massive blowup last night through today and tonight would have been better because probably an ERC would happen before landfall...it may now end up going through its peak cycle up until approach which is underrated as far as how well winds reach the surface.  A 130mph storm undergoing an ERC can cause less wind damage sometimes than a rapidly intensifying 105mph storm...we've seen this a few times in recent year.

[beanskip]

12z ICON: West

12z GFS through 51 hours: West (of its westernmost solution).

Euro still a safe bet, but it is becoming increasingly isolated to the east. 

[dan11295]

12Z GFS is basically over Tallahassee at 18Z Wednesday.

[beanskip]

CMC goes east -- basically the first model to trend that way since 18z runs yesterday. 

[NeffsvilleWx]

32 minutes ago, dan11295 said:

Guidance has been consistent or more or less keeping Idalia in check into shear lessen N of Cuba later tonight/early tomorrow.

 

You could see the sheer impact this morning as an outflow boundary from collapsing convection shot out to the east.

[NERMAN]

12z GFS came in with the same intensity as 06z, as a Cat 3

[TPAwx]

Euro remains to be seen, even with some westward movement on other guidance no reason for local TB region media mets and municipal officials to let up on messaging and urgency, esp for Zone A and B residents,

[dbullsfan]

I don’t know, seems like the Tampa bubble is in full effect her and this is gonna end up staying north and west


.

[Jersey Andrew]

4 minutes ago, TPAwx said:

Euro remains to be seen, even with some westward movement on other guidance no reason for local TB region media mets and municipal officials to let up on messaging and urgency, esp for Zone A and B residents,

After the debacle in Fort Myers last year surrounding late ordered evacuations, Tampa metro has to be very concerned about storm track and surge threat. Weren’t Zone A and B evacuated last year before Ian took a more southerly track? Tough decisions ahead.

[Hotair]

Evac orders at this time