Hurricane Idalia

[WxWatcher007]

1:00 AM CDT Mon Aug 28
Location: 19.7°N 85.3°W
Moving: Stationary
Min pressure: 990 mb
Max sustained: 60 mph

[negative-nao]

[Floydbuster]

990 mb on the new advisory. This thing will definitely trend towards a lower than normal pressure. Reminds me a bit of Hurricane Isidore in 2002 (which also did a loop near the Yucatan Peninsula). Isidore started as a tropical storm with a lower pressure similar to Idalia, and ended up being down to 934 mb despite only having winds of 125 mph.

[WxWatcher007]

Recon moving toward a NE to SW pass. Should get a lot of good info in the next 30 minutes or so. 

[WxWatcher007]

992.2mb extrapolated on the second pass. Peak FL of 53kts and SFMR of 47 & 48kts. Idalia has made a lot of progress in the last 24 hours in tightening up, but it's not there yet in terms of developing a nascent inner core. Not enough upshear thunderstorm activity is limiting intensification. For now. 

[WxSynopsisDavid]

1 minute ago, WxWatcher007 said:

992.2mb extrapolated on the second pass. Peak FL of 53kts and SFMR of 47 & 48kts. Idalia has made a lot of progress in the last 24 hours in tightening up, but it's not there yet in terms of developing a nascent inner core. Not enough upshear thunderstorm activity is limiting intensification. For now. 

My suspicion is that there is some sort of internal process happening. Next 3-6hrs will be interesting.

[WxSynopsisDavid]

989mb

[WxWatcher007]

Yeah I mean as long as there are deep convective bursts like this it makes it more likely we see it wrap up. The hurricane models have had a good handle on its structure looking at 00z. It may take time, but a legitimate signal remains for a major hurricane. 

Latest dropsonde suggests that the pressures are lower than the extrapolated, and the first sonde about an hour ago, so it's moving along...

Off to bed now. Night everyone.  

 

Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 28th day of the month at 6:24Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5304
Storm Name: Idalia
Storm Number: 10 (flight in the North Atlantic basin)
Mission Number: 3
Observation Number: 15 ( See all messages of this type for this mission. )

Part A...
 

Date: Near the closest hour of 6Z on the 28th day of the month
Highest Mandatory Level For Which Wind Was Reported: 925mb
Coordinates: 19.8N 85.2W
Location: 143 statute miles (229 km) to the SE (131°) from Cancún, Quintana Roo, Mexico.
Marsden Square: 045 ( About )
 

Surface and Standard Isobaric Surfaces
Level	Geo. Height	Air Temp.	Dew Point	Wind Direction	Wind Speed
1000mb	-96m (-315 ft)	This level does not exist in this area of the storm above the surface level.
989mb (29.21 inHg)	Surface (Sea Level)	28.0°C (82.4°F)	26.4°C (80°F)	240° (from the WSW)	13 knots (15 mph)
925mb	597m (1,959 ft)	24.2°C (75.6°F)	23.6°C (74°F)	230° (from the SW)	11 knots (13 mph)
850mb	1,341m (4,400 ft)	24.4°C (75.9°F)	About 17°C (63°F)	No Wind Report Available For This Level

Information About Radiosonde:
- Launch Time: 6:19Z
- 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: 19.81N 85.19W
- Time: 6:19:25Z

Lowest altitude where wind was reported:
- Location: 19.82N 85.19W
- Time: 6:21:23Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 230° (from the SW)
- Wind Speed: 12 knots (14 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 230° (from the SW)
- Wind Speed: 10 knots (12 mph)
- Depth of Sounding: From 852mb to 989mb

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: 230° (from the SW)
- Wind Speed: 12 knots (14 mph)

Sounding Software Version: AEV 30407
 

Part B: Data for Significant Levels...
 

Significant Temperature And Relative Humidity Levels
Level	Air Temperature	Dew Point
989mb (Surface)	28.0°C (82.4°F)	26.4°C (80°F)
907mb	23.4°C (74.1°F)	23.2°C (74°F)
850mb	24.4°C (75.9°F)	About 17°C (63°F)
843mb	Unavailable

 

Significant Wind Levels
Level	Wind Direction	Wind Speed
989mb (Surface)	240° (from the WSW)	13 knots (15 mph)
980mb	230° (from the SW)	12 knots (14 mph)
928mb	225° (from the SW)	12 knots (14 mph)
887mb	240° (from the WSW)	10 knots (12 mph)
864mb	190° (from the S)	7 knots (8 mph)
852mb	280° (from the W)	1 knots (1 mph)

[WxSynopsisDavid]

6 minutes ago, WxWatcher007 said:

Yeah I mean as long as there are deep convective bursts like this it makes it more likely we see it wrap up. The hurricane models have had a good handle on its structure looking at 00z. It may take time, but a legitimate signal remains for a major hurricane. 

Latest dropsonde suggests that the pressures are lower than the extrapolated, and the first sonde about an hour ago, so it's moving along...

Off to bed now. Night everyone.  

 

Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 28th day of the month at 6:24Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5304
Storm Name: Idalia
Storm Number: 10 (flight in the North Atlantic basin)
Mission Number: 3
Observation Number: 15 ( See all messages of this type for this mission. )

Part A...
 

Date: Near the closest hour of 6Z on the 28th day of the month
Highest Mandatory Level For Which Wind Was Reported: 925mb
Coordinates: 19.8N 85.2W
Location: 143 statute miles (229 km) to the SE (131°) from Cancún, Quintana Roo, Mexico.
Marsden Square: 045 ( About )
 

Surface and Standard Isobaric Surfaces
Level	Geo. Height	Air Temp.	Dew Point	Wind Direction	Wind Speed
1000mb	-96m (-315 ft)	This level does not exist in this area of the storm above the surface level.
989mb (29.21 inHg)	Surface (Sea Level)	28.0°C (82.4°F)	26.4°C (80°F)	240° (from the WSW)	13 knots (15 mph)
925mb	597m (1,959 ft)	24.2°C (75.6°F)	23.6°C (74°F)	230° (from the SW)	11 knots (13 mph)
850mb	1,341m (4,400 ft)	24.4°C (75.9°F)	About 17°C (63°F)	No Wind Report Available For This Level

Information About Radiosonde:
- Launch Time: 6:19Z
- 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: 19.81N 85.19W
- Time: 6:19:25Z

Lowest altitude where wind was reported:
- Location: 19.82N 85.19W
- Time: 6:21:23Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 230° (from the SW)
- Wind Speed: 12 knots (14 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 230° (from the SW)
- Wind Speed: 10 knots (12 mph)
- Depth of Sounding: From 852mb to 989mb

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: 230° (from the SW)
- Wind Speed: 12 knots (14 mph)

Sounding Software Version: AEV 30407
 

Part B: Data for Significant Levels...
 

Significant Temperature And Relative Humidity Levels
Level	Air Temperature	Dew Point
989mb (Surface)	28.0°C (82.4°F)	26.4°C (80°F)
907mb	23.4°C (74.1°F)	23.2°C (74°F)
850mb	24.4°C (75.9°F)	About 17°C (63°F)
843mb	Unavailable

 

Significant Wind Levels
Level	Wind Direction	Wind Speed
989mb (Surface)	240° (from the WSW)	13 knots (15 mph)
980mb	230° (from the SW)	12 knots (14 mph)
928mb	225° (from the SW)	12 knots (14 mph)
887mb	240° (from the WSW)	10 knots (12 mph)
864mb	190° (from the S)	7 knots (8 mph)
852mb	280° (from the W)	1 knots (1 mph)

Night man, thanks for the analysis and breakdown of recon data.

[40/70 Benchmark]

Here is my first stab at it.

https://easternmassweather.blogspot.com/2023/08/newly-formed-idalia-likely-to-strike.html?m=1

[Hotair]

20 minutes ago, 40/70 Benchmark said:

Here is my first stab at it.

https://easternmassweather.blogspot.com/2023/08/newly-formed-idalia-likely-to-strike.html?m=1

Uni of Florida should be preparing for a possible direct hit given this scenario

[GaWx]

1 hour ago, 40/70 Benchmark said:

Here is my first stab at it.

https://easternmassweather.blogspot.com/2023/08/newly-formed-idalia-likely-to-strike.html?m=1

 Even though Cedar Key is 90 miles from Tampa, a strong cat 3 landfall like your first stab shows would I believe put Tampa Bay at risk for a 7-8 foot storm surge based on analogs. That would make it the highest surge there since 1921. Thus, that might seem overdone. But keep in mind that in 1950 on Sep 5, H Easy initially hit Cedar Key moving NE where it had a 958 mb/120 mph/cat 3 landfall. There was a 6.5 foot surge at Tampa Bay. Adding some for your slightly stronger 125 mph as well as you having it way up at 150 mph 24 hours earlier tells me that there'd probably be a risk of a bit higher than this analog's 6.5 foot surge.

 What's even more scary is that 2020's Eta was only a 50 mph TS when it, too, landfalled at Cedar Key (moving NNE like Idalia is projected to do) and it was able to produce a 4.2 foot surge at Tampa Bay! If a 50 mph TS centered up at Cedar Key can produce a 4.2 foot surge, I'd think that a 125 mph H centered in the same area could conceivably produce near double that. Then again, there may have been some highly unusual circumstances with Eta that won't be present with Idalia.

[CheeselandSkies]

0Z HAFS-B gets it down to 929 MB (strongest non-fantasy range hurricane model output I've seen thus far) at FH057, but brings it back up a bit before landfall. All the hurricane models (and have for several runs) agree on a solid major hurricane, potentially a high-end (125kt+) one.

[40/70 Benchmark]

18 minutes ago, GaWx said:

 Even though Cedar Key is 90 miles from Tampa, a strong cat 3 landfall like your first stab shows would I believe put Tampa Bay at risk for a 7-8 foot storm surge based on analogs. That would make it the highest surge there since 1921. Thus, that might seem overdone. But keep in mind that in 1950 on Sep 5, H Easy initially hit Cedar Key moving NE where it had a 958 mb/120 mph/cat 3 landfall. There was a 6.5 foot surge at Tampa Bay. Adding some for your slightly stronger 125 mph as well as you having it way up at 150 mph 24 hours earlier tells me that there'd probably be a risk of a bit higher than this analog's 6.5 foot surge.

 What's even more scary is that 2020's Eta was only a 50 mph TS when it, too, landfalled at Cedar Key (moving NNE like Idalia is projected to do) and it was able to produce a 4.2 foot surge at Tampa Bay! If a 50 mph TS centered up at Cedar Key can produce a 4.2 foot surge, I'd think that a 125 mph H centered in the same area could conceivably produce near double that. Then again, there may have been some highly unusual circumstances with Eta that won't be present with Idalia.

One saving grace, Larry is that it probably won't have much time to expand.

[LakeEffectKing]

Seen this dog and pony show before....too many parameters trending positive for RI in 18-36 hrs.

Idalia should easily be a major by tomorrow, and may very well be CAT 4 by 06z Wed.

[WxSynopsisDavid]

1 minute ago, LakeEffectKing said:

Seen this dog and pony show before....too many parameters trending positive for RI in 18-36 hrs.

Idalia should easily be a major by tomorrow, and may very well be CAT 4 by 06z Wed.

Once that vertical column stacks, it’s game on. We are close now to that happening.

[LakeEffectKing]

2 minutes ago, WxSynopsisDavid said:

Once that vertical column stacks, it’s game on. We are close now to that happening.

Probably in the next 18-24 hrs. Takes a bit of time to get all levels aligned AND to clear out the center....then boom!

[WxSynopsisDavid]

4 minutes ago, LakeEffectKing said:

Probably in the next 18-24 hrs. Takes a bit of time to get all levels aligned AND to clear out the center....then boom!

I’ll take that bet and say 12hrs tops. So far what Idalia was able to pull off with 30kts of shear was impressive. 
 

Also….Idalia is now beginning to interact with a noticeable warm eddy so I think because of this the process happens much sooner.

[Rtd208]

I know everyone is concentrating on Florida but eventually there are going to be some impacts in GA, SC and NC as well.

[WxSynopsisDavid]

3 minutes ago, Rtd208 said:

I know everyone is concentrating on Florida but eventually there are going to be some impacts in GA, SC and NC as well.

No one has forgotten but there are still uncertainties on track and intensity. Unfortunately we won’t really know for sure what those impacts will be until Tuesday. 

[WxWatcher007]

3 hours ago, 40/70 Benchmark said:

Here is my first stab at it.

https://easternmassweather.blogspot.com/2023/08/newly-formed-idalia-likely-to-strike.html?m=1

Always appreciate seeing your thoughts. Nice write up. 

[SnoSki14]

1 hour ago, LakeEffectKing said:

Seen this dog and pony show before....too many parameters trending positive for RI in 18-36 hrs.

Idalia should easily be a major by tomorrow, and may very well be CAT 4 by 06z Wed.

I think there are much more negative factors than with previous storms. A lot of dry air and shear present and it won't ever get fully favorable.

Plus time will be a factor. I don't think warm SSTs alone will do it.

I don't expect more than a Cat 2 at landfall.

[WxSynopsisDavid]

1 minute ago, SnoSki14 said:

I think there are much more negative factors than with previous storms. A lot of dry air and shear present and it won't ever get fully favorable.

Plus time will be a factor. I don't think warm SSTs alone will do it.

I don't expect more than a Cat 2 at landfall.

Shear has actually rapidly decreased the last 3 hours. Shear values north of Idalia went from 40kts to 25kts now. Dry air has abated the core and there’s little dry air to the north. This is a similar environment that Michael had in all honesty. One could argue a better environment ahead than what Michael had.

[WxWatcher007]

Morning, everyone. There are going to be numerous missions at high and low altitude through landfall for Idalia now. The first morning low altitude flight is descending now. This is mission 5. An additional flight, mission 6, is starting to descend as well. 

[nycwinter]

21 minutes ago, SnoSki14 said:

I think there are much more negative factors than with previous storms. A lot of dry air and shear present and it won't ever get fully favorable.

Plus time will be a factor. I don't think warm SSTs alone will do it.

I don't expect more than a Cat 2 at landfall.

Over the Gulf of Mexico, the environment is forecast to become 
conducive for significant strengthening of Idalia due to a new 
trough dropping south over the western Gulf of Mexico as a 
upper-level ridge builds near the cyclone.  Additionally, Idalia 
will be moving over waters near 31C, and some of the guidance is 
even indicating favorable jet dynamics on Wednesday with Idalia in 
the right-rear quadrant of the jet over the southeastern United 
States.  The bottom line is that rapid intensification is becoming 
increasingly likely before landfall, and the NHC forecast now 
explicitly indicates it between 24-48 h in the forecast.  This is 
consistent with almost all of the regional hurricane models and the 
SHIPS rapid intensification indices, which are 5-10 times the 
climatological mean.  The new prediction shows a 100-kt hurricane 
over the eastern Gulf of Mexico at 48 hours, but Idalia should keep 
strengthening up to landfall along the Gulf coast of Florida.  
Interests within the storm surge and hurricane watch areas are urged 
to prepare for possible significant impacts and monitor future 
updates to the forecast for this increasingly dangerous situation.

[WxWatcher007]

Mission 5 approaching the center to do a NW to SE pass. Getting a better sense of the wind field in each quadrant, as well as if there's a low level attempt at developing an eyewall is what I'm paying close attention to. It looks like it's trying again on radar, but recon will confirm. Idalia is clearly getting closer, however, and we're starting to see--for now at least--some convection to the north trying to wrap around. 

[WxWatcher007]

Mission 5 first pass produced an extrapolated pressure of 990.4mb. Peak FL wind of 50kt and unflagged peak SFMR of 55kt. 

Edit: basically confirms 5am intensity. 

[WxWatcher007]

Center dropsonde

 

Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 28th day of the month at 11:25Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF99-5309
Storm Name: Idalia
Storm Number: 10 (flight in the North Atlantic basin)
Mission Number: 5
Observation Number: 06 ( See all messages of this type for this mission. )

Part A...
 

Date: Near the closest hour of 11Z on the 28th day of the month
Highest Mandatory Level For Which Wind Was Reported: 850mb
Coordinates: 20.6N 85.1W
Location: 120 statute miles (193 km) to the ESE (109°) from Cancún, Quintana Roo, Mexico.
Marsden Square: 081 ( About )
 

Surface and Standard Isobaric Surfaces
Level	Geo. Height	Air Temp.	Dew Point	Wind Direction	Wind Speed
1000mb	-93m (-305 ft)	This level does not exist in this area of the storm above the surface level.
990mb (29.24 inHg)	Surface (Sea Level)	27.8°C (82.0°F)	25.7°C (78°F)	125° (from the SE)	12 knots (14 mph)
925mb	599m (1,965 ft)	24.4°C (75.9°F)	22.3°C (72°F)	150° (from the SSE)	9 knots (10 mph)
850mb	1,340m (4,396 ft)	21.2°C (70.2°F)	19.8°C (68°F)	150° (from the SSE)	8 knots (9 mph)

Information About Radiosonde:
- Launch Time: 11:18Z
- 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: 20.61N 85.14W
- Time: 11:18:37Z

Lowest altitude where wind was reported:
- Location: 20.61N 85.14W
- Time: 11:20:49Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 130° (from the SE)
- Wind Speed: 11 knots (13 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 140° (from the SE)
- Wind Speed: 9 knots (10 mph)
- Depth of Sounding: From 843mb to 989mb

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: 125° (from the SE)
- Wind Speed: 13 knots (15 mph)

Sounding Software Version: AEV 30407
 

Part B: Data for Significant Levels...
 

Significant Temperature And Relative Humidity Levels
Level	Air Temperature	Dew Point
990mb (Surface)	27.8°C (82.0°F)	25.7°C (78°F)
850mb	21.2°C (70.2°F)	19.8°C (68°F)

 

Significant Wind Levels
Level	Wind Direction	Wind Speed
990mb (Surface)	125° (from the SE)	12 knots (14 mph)
957mb	125° (from the SE)	10 knots (12 mph)
904mb	155° (from the SSE)	10 knots (12 mph)
854mb	140° (from the SE)	8 knots (9 mph)
843mb	165° (from the SSE)	8 knots (9 mph)

[beanskip]

Seems to be no mention of the decided westward trends in some of the models (in addition to the pronounced slowing trend). 0z Euro went slightly west. The HMON went more than a full degree of longtitude west. CMC -- west. GFS held serve with its western track.

 

[WxWatcher007]

Mission 6 is doing a pass from N to S and has an extrapolated pressure so far of 985.1mb. The caveat here is that this is being extrapolated from an altitude of ~12,300ft. SFMR peak winds consistent with Mission 5 so far.