Hurricane Idalia

[NERMAN]

1 hour ago, TriPol said:

I'd wager a hefty sum that the likelihood of a landfall event in the Florida Panhandle is rather minimal, a hypothesis that I find somewhat at odds with the current projections from the National Hurricane Center. Since the case of Hurricane Charlie, Gulf-originating hurricanes to veer westward in their tracks, particularly when their initial trajectories are not aimed at Texas, Louisiana, or the Mississippi/Alabama coastline. This westward bias is often less pronounced when a robust anticyclonic system is situated over Florida, effectively serving as a protective barrier for the state's western coastline. One could argue that the NHC's forecasting methodology could benefit from a reevaluation of these recurrent patterns, especially in the context of recent advancements in ensemble forecasting and data assimilation techniques.

I'm not quite sure I follow you? Are you suggesting the current NHC cone area for landfall (say cedar key to big bend) is unlikely to play out?

[WxSynopsisDavid]

8 minutes ago, Eskimo Joe said:

 

 

Good lord that’s a tight, compact eye. If that thing stays looking like a pinhole, I would hate to be the recon hunters having to fly into that sucker later today. 

[WxWatcher007]

Looking at Cuba and now Key West radar you can see an increasingly organized system. That first recon pass and VDM will be very interesting. 

[NERMAN]

28 minutes ago, WxWatcher007 said:

Recon is in the air and will soon provide critical structural and heading data on a strengthening Hurricane Idalia. 

Idalia has remained resilient in the face of moderate shear the last few days, gradually organizing and attempting to fire convection consistent enough to establish an inner core. This morning satellite and radar show that with shear decreasing Idalia is beginning to develop an inner core, with deep convection rotating around the center in the image above and an eye feature evident on radar. 

Recon will be important in assessing just how far along this inner core process has progressed, and whether there is still significant vortex tilting, which can still be possible if there's enough shear still present. My guess looking at the radar however, is that the vortex tilting that was an issue 24 hours ago is no longer enough to keep this from increasing its rate of intensification. 

According to CMISS analysis, shear is now in the favorable zone and expected to remain so until landfall.

As the trough sets up during Idalia's final approach, upper diffluence combined with increasing OHC and SSTs will almost certainly allow for rapid intensification. 

(SST image courtesy of Brian McNoldy)

Once rapid intensification occurs, and it is explicitly forecast by the NHC, we don't know where it'll stop. Time will be a limiting factor, but it cuts both ways. On on hand, there may not be enough time for the very high ceiling for Idalia to be reached. On the other, the lack of time means that a structural change, such as an Eyewall Replacement Cycle (ERC) is less likely. 

There is also modest but meaningful divergence in track.

The consensus among most guidance is to bring this further north, while the European Model and stronger members of the EPS have a further east landfall. It's been talked about around here but we will need to watch for deviations closely, as there are almost always small changes that have a substantial impact on sensible weather.

To be clear--nobody living in the region should merely look at the center track. Heavy rain, storm surge, and strong to destructive winds will be possible far outside the center. Given the parallel run up the west coast of Florida however, where the center landfalls is obviously important for surge and strongest wind impacts. The 06z GFS ticked ever so slightly east relative to 00z. 

Watch the organizational trends, pace of intensification, and the wobbles relative to long term heading.

It should be an active day.

Great write-up. I've been comparing this storm to Michael and there are a lot of similarities in the conditions, path, profile and current status. If it can get to a Cat 2 quickly then it would have more time than Michael needed to make a run at Cat 5. I know it's HIGHLY UNLIKELY because that was a perfect scenario, and I'm not doomcasting or wishing, just throwing it out there the real possibility of intense RI over the next 24 hours. 

[the_other_guy]

1 hour ago, dan11295 said:

Tbh anything within 20 miles or so of current forecast is probably a best case scenario as far as damage. less surge for Tampa, but keeps it E of Apalachee Bay.

Couldnt be better for Tampa metro on current track. Another dodge

[Eskimo Joe]

 

 

[beanskip]

From the top of the TLH AFD:

National Weather Service Tallahassee FL
510 AM EDT Tue Aug 29 2023

...IDALIA EXPECTED TO SLAM THE FLORIDA BIG BEND AS A MAJOR HURRICANE
EARLY WEDNESDAY MORNING...
...New NEAR TERM, SHORT TERM, LONG TERM, AVIATION, MARINE, FIRE WEATHER, HYDROLOGY...

.NEAR TERM...
(Today)
Issued at 504 AM EDT Tue Aug 29 2023

You need to complete your preparations today if you live in the
Florida big bend. To put this system into the historical context,
there are NO major hurricanes in the historical dataset going back
to 1851 that have tracked into Apalachee Bay. None. Don`t mess
around with this. Follow the advice of your local emergency
management.

[beanskip]

It's pretty remarkable that the GFS and all 3 hurricane models show a direct hit on Wakulla and Leon counties -- in a little over 24 hours -- and both counties are only under a Tropical Storm Warning. I worry that an Apalachee Bay hit will catch many off guard. 

https://www.weather.gov/tae/

https://www.tallahassee.com/story/news/hurricane/2023/08/29/hurricane-idalia-updates-for-tallahassee-big-bend-models-track-florida/70705962007/

[WxWatcher007]

First pass from N to S has an extrapolated pressure of 973.9mb at about 10k ft. Awaiting dropsonde and sampling of southern portion of possible eyewall.

[40/70 Benchmark]

1 hour ago, WxWatcher007 said:

Recon is in the air and will soon provide critical structural and heading data on a strengthening Hurricane Idalia. 

Idalia has remained resilient in the face of moderate shear the last few days, gradually organizing and attempting to fire convection consistent enough to establish an inner core. This morning satellite and radar show that with shear decreasing Idalia is beginning to develop an inner core, with deep convection rotating around the center in the image above and an eye feature evident on radar. 

Recon will be important in assessing just how far along this inner core process has progressed, and whether there is still significant vortex tilting, which can still be possible if there's enough shear still present. My guess looking at the radar however, is that the vortex tilting that was an issue 24 hours ago is no longer enough to keep this from increasing its rate of intensification. 

According to CMISS analysis, shear is now in the favorable zone and expected to remain so until landfall.

As the trough sets up during Idalia's final approach, upper diffluence combined with increasing OHC and SSTs will almost certainly allow for rapid intensification. 

(SST image courtesy of Brian McNoldy)

Once rapid intensification occurs, and it is explicitly forecast by the NHC, we don't know where it'll stop. Time will be a limiting factor, but it cuts both ways. On on hand, there may not be enough time for the very high ceiling for Idalia to be reached. On the other, the lack of time means that a structural change, such as an Eyewall Replacement Cycle (ERC) is less likely. 

There is also modest but meaningful divergence in track.

The consensus among most guidance is to bring this further north, while the European Model and stronger members of the EPS have a further east landfall. It's been talked about around here but we will need to watch for deviations closely, as there are almost always small changes that have a substantial impact on sensible weather.

To be clear--nobody living in the region should merely look at the center track. Heavy rain, storm surge, and strong to destructive winds will be possible far outside the center. Given the parallel run up the west coast of Florida however, where the center landfalls is obviously important for surge and strongest wind impacts. The 06z GFS ticked ever so slightly east relative to 00z. 

Watch the organizational trends, pace of intensification, and the wobbles relative to long term heading.

It should be an active day.

Nice post. Only two issues with my thoughts from late Sunday/early Monday is that I rushed the RI by about 12 hours by underplaying the initial shear a bit, and probably need to adjust west a tad.

[WxWatcher007]

Kind of a ho hum pass there. Good look structurally but FL and SFMR are not particularly strong. Peak SFMR just under 64kt. That said, that was N to S. I expect stronger findings on the eastern side. 

[Griizzcoat]

EYE getting going for sure

https://weather.cod.edu/satrad/?parms=meso-meso1-14-96-1-25-1&checked=map&colorbar=undefined

[StantonParkHoya]

This thing is booking it north

[WxWatcher007]

As expected. Dropsonde in the southern eyewall is quite a bit stronger than the northern side right now. 

Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)
Transmitted: 29th day of the month at 11:45Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Lockheed WP-3D Orion (Reg. Num. N43RF)
Storm Name: Idalia
Storm Number: 10 (flight in the North Atlantic basin)
Mission Number: 10
Observation Number: 06 ( See all messages of this type for this mission. )

Part A...
 

Date: Near the closest hour of 12Z on the 29th day of the month
Highest Mandatory Level For Which Wind Was Reported: 850mb
Coordinates: 23.5N 84.7W
Location: 151 statute miles (242 km) to the W (280°) from Havana, Cuba.
Marsden Square: 081 ( About )
 

Surface and Standard Isobaric Surfaces
Level	Geo. Height	Air Temp.	Dew Point	Wind Direction	Wind Speed
1000mb	-99m (-325 ft)	This level does not exist in this area of the storm above the surface level.
989mb (29.21 inHg)	Surface (Sea Level)	27.2°C (81.0°F)	25.8°C (78°F)	210° (from the SSW)	66 knots (76 mph)
925mb	591m (1,939 ft)	23.2°C (73.8°F)	22.4°C (72°F)	230° (from the SW)	75 knots (86 mph)
850mb	1,328m (4,357 ft)	20.4°C (68.7°F)	17.9°C (64°F)	255° (from the WSW)	76 knots (87 mph)
700mb	2,988m (9,803 ft)	Other data not available.

Information About Radiosonde:
- Launch Time: 11:30Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.

Remarks Section...
 

Dropsonde Location: Dropped in eyewall 180° (S) from the eye center.

Highest altitude where wind was reported:
- Location: 23.52N 84.74W
- Time: 11:30:11Z

Lowest altitude where wind was reported:
- Location: 23.55N 84.66W
- Time: 11:34:30Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 220° (from the SW)
- Wind Speed: 73 knots (84 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 250° (from the WSW)
- Wind Speed: 66 knots (76 mph)
- Depth of Sounding: From 707mb to 988mb

Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 154 gpm - 4 gpm (505 geo. feet - 13 geo. feet)
- Wind Direction: 215° (from the SW)
- Wind Speed: 71 knots (82 mph)

Sounding Software Version: AEV 30409
 

Part B: Data for Significant Levels...
 

Significant Temperature And Relative Humidity Levels
Level	Air Temperature	Dew Point
989mb (Surface)	27.2°C (81.0°F)	25.8°C (78°F)
935mb	23.6°C (74.5°F)	23.0°C (73°F)
850mb	20.4°C (68.7°F)	17.9°C (64°F)
700mb	13.0°C (55.4°F)	12.6°C (55°F)

 

Significant Wind Levels
Level	Wind Direction	Wind Speed
989mb (Surface)	210° (from the SSW)	66 knots (76 mph)
967mb	220° (from the SW)	76 knots (87 mph)
961mb	220° (from the SW)	72 knots (83 mph)
939mb	225° (from the SW)	76 knots (87 mph)
850mb	255° (from the WSW)	76 knots (87 mph)
707mb	275° (from the W)	56 knots (64 mph)

[bigtenfan]

Looking somewhat further ahead:  Some of this morning long range guidance has storm  this doing a full loop once off shore and circling around to be a threat to the SE coast of Florida. Are the steering currents that crazy for that to be a reasonable possibility?

[WxWatcher007]

Center dropsonde. Pressure probably down to about 977mb. 

 

Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)
Transmitted: 29th day of the month at 11:38Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Lockheed WP-3D Orion (Reg. Num. N43RF)
Storm Name: Idalia
Storm Number: 10 (flight in the North Atlantic basin)
Mission Number: 10
Observation Number: 05

Part A...
 

Date: Near the closest hour of 11Z on the 29th day of the month
Highest Mandatory Level For Which Wind Was Reported: 850mb
Coordinates: 23.7N 84.7W
Location: 154 statute miles (247 km) to the WNW (285°) from Havana, Cuba.
Marsden Square: 081 ( About )
 

Surface and Standard Isobaric Surfaces
Level	Geo. Height	Air Temp.	Dew Point	Wind Direction	Wind Speed
1000mb	-193m (-633 ft)	This level does not exist in this area of the storm above the surface level.
979mb (28.91 inHg)	Surface (Sea Level)	29.6°C (85.3°F)	27.4°C (81°F)	235° (from the SW)	20 knots (23 mph)
925mb	504m (1,654 ft)	25.6°C (78.1°F)	24.6°C (76°F)	245° (from the WSW)	23 knots (26 mph)
850mb	1,249m (4,098 ft)	24.0°C (75.2°F)	19.8°C (68°F)	240° (from the WSW)	20 knots (23 mph)
700mb	2,932m (9,619 ft)	16.4°C (61.5°F)	12.9°C (55°F)	No Wind Report Available For This Level

Information About Radiosonde:
- Launch Time: 11:27Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.

Remarks Section...
 

Dropsonde Location: Dropped in center.

Highest altitude where wind was reported:
- Location: 23.72N 84.74W
- Time: 11:27:26Z

Lowest altitude where wind was reported:
- Location: 23.72N 84.72W
- Time: 11:31:33Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 250° (from the WSW)
- Wind Speed: 24 knots (28 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 255° (from the WSW)
- Wind Speed: 17 knots (20 mph)
- Depth of Sounding: From 706mb to 978mb

Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 155 gpm - 5 gpm (509 geo. feet - 16 geo. feet)
- Wind Direction: 250° (from the WSW)
- Wind Speed: 24 knots (28 mph)

Sounding Software Version: AEV 30409
 

Part B: Data for Significant Levels...
 

Significant Temperature And Relative Humidity Levels
Level	Air Temperature	Dew Point
979mb (Surface)	29.6°C (85.3°F)	27.4°C (81°F)
908mb	24.4°C (75.9°F)	24.0°C (75°F)
850mb	24.0°C (75.2°F)	19.8°C (68°F)
796mb	22.2°C (72.0°F)	About 17°C (63°F)
727mb	17.2°C (63.0°F)	15.6°C (60°F)
699mb	16.4°C (61.5°F)	12.7°C (55°F)

 

Significant Wind Levels
Level	Wind Direction	Wind Speed
979mb (Surface)	235° (from the SW)	20 knots (23 mph)
968mb	250° (from the WSW)	25 knots (29 mph)
850mb	240° (from the WSW)	20 knots (23 mph)
791mb	260° (from the W)	11 knots (13 mph)
743mb	310° (from the NW)	11 knots (13 mph)
706mb	300° (from the WNW)	7 knots (8 mph)

[WxWatcher007]

7:00 AM CDT Tue Aug 29
Location: 23.8°N 84.8°W
Moving: N at 14 mph
Min pressure: 977 mb
Max sustained: 80 mph
 

[SolidIcewx]

Looking strong so far. Can see more new convection wrapping around. The train is moving so to speak 

[WxWatcher007]

First VDM confirms the presence of an eye

 

Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 29th day of the month at 11:57Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Lockheed WP-3D Orion (Reg. Num. N43RF)
Storm Name: Idalia
Storm Number & Year: 10 in 2023 (flight in the North Atlantic basin)
Mission Number: 10
Observation Number: 08 ( See all messages of this type for this mission. )

A. Time of Center Fix: 29th day of the month at 11:27:00Z
B. Center Fix Coordinates: 23.73N 84.75W
B. Center Fix Location: 157 statute miles (253 km) to the WNW (286°) from Havana, Cuba.
C. Minimum Height at Standard Level: 2,931m (9,616ft) at 700mb
D. Minimum Sea Level Pressure: 979mb (28.91 inHg)
E. Dropsonde Surface Wind at Center: From 235° at 20kts (From the SW at 23mph)
F. Eye Character: Spiral Band
G. Eye Shape & Diameter: Circular with a diameter of 20 nautical miles (23 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 63kts (72.5mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 10 nautical miles (12 statute miles) to the NNW (343°) of center fix at 11:24:36Z
J. Maximum Flight Level Wind Inbound: From 93° at 46kts (From the E at 52.9mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 12 nautical miles (14 statute miles) to the NNW (344°) of center fix at 11:23:56Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 62kts (71.3mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 12 nautical miles (14 statute miles) to the S (178°) of center fix at 11:29:54Z
N. Maximum Flight Level Wind Outbound: From 270° at 58kts (From the W at 66.7mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 18 nautical miles (21 statute miles) to the S (178°) of center fix at 11:31:09Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 15°C (59°F) at a pressure alt. of 3,060m (10,039ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 18°C (64°F) at a pressure alt. of 3,070m (10,072ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 15°C (59°F)
R. Sea Surface Temp (collected at same location as temp inside eye): Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: 700mb
T. Navigational Fix Accuracy: 0.01 nautical miles
T. Meteorological Accuracy: 2 nautical miles

Remarks Section:
 

Maximum Flight Level Wind: 58kts (~ 66.7mph) which was observed 18 nautical miles (21 statute miles) to the S (178°) from the flight level center at 11:31:09Z

[40/70 Benchmark]

1 hour ago, WxWatcher007 said:

Didn't add to the post, but recent microwave imagery suggests a nearly completed eyewall. 

Def. gonna be using some of your images for my Final thoughts on this for the sake of time, if you don't mind....

[Brian5671]

12 minutes ago, bigtenfan said:

Looking somewhat further ahead:  Some of this morning long range guidance has storm  this doing a full loop once off shore and circling around to be a threat to the SE coast of Florida. Are the steering currents that crazy for that to be a reasonable possibility?

Would be a shell of its former self by then

[CoastalWx]

27 minutes ago, 40/70 Benchmark said:

Nice post. Only two issues with my thoughts from late Sunday/early Monday is that I rushed the RI by about 12 hours by underplaying the initial shear a bit, and probably need to adjust west a tad.

It’s still got some kinks to work out. I’d say later today and tonight is the opportunity to take off. 

[40/70 Benchmark]

Just now, CoastalWx said:

It’s still got some kinks to work out. I’d say later today and tonight is the opportunity to take off. 

Yea, my time-table was off by about 12-24 hours...I shouldn't have dismissed that initial shear, but I am not sure that is a good thing for the coast when all is said and done.

[WxWatcher007]

6 minutes ago, CoastalWx said:

It’s still got some kinks to work out. I’d say later today and tonight is the opportunity to take off. 

Yeah, it really doesn’t take off until this afternoon on the hurricane guidance, and it’s a 120kt storm on HAFS A & B.

[cardinalland]

lots of storms have been intensifying up to landfall recently and the northeast GOM is quite hot/above normal unfortunately

[CoastalWx]

10 minutes ago, 40/70 Benchmark said:

Yea, my time-table was off by about 12-24 hours...I shouldn't have dismissed that initial shear, but I am not sure that is a good thing for the coast when all is said and done.

Right. If it’s intensifying right until landfall that allows the strongest winds to mix down.

[40/70 Benchmark]

2 minutes ago, CoastalWx said:

Right. If it’s intensifying right until landfall that allows the strongest winds to mix down.

Yes....also less time for ERC...the only positive is that it won't be a worst case for surge, as ERCs are a vehicle for growth. Later intensification also means less time to pile water. This is potentially a worst case for wind, not surge.

[40/70 Benchmark]

I expect the worst damage to be fairly concentrated near and just to the east of LF.

[schoeppeya]

Looking at radar it looks like we are about to have our first fully closed eye shortly.

[SnowBeau]

The 5AM NHC forecast didn’t have Idalia hitting 84.8W until 5PM, yet it’s already there at 8AM.  Just a wobble, or is that significant?