Hurricane Idalia

[hawkeye_wx]

1 minute ago, WxWatcher007 said:

970.5mb extrapolated pressure. FL and SFMR not impressive with peak of 53kt at FL and 63kt SFMR. First pass though.

Recon data doesn't look much better than earlier.  Dropsonde will probably say a 1 or 2 mb drop, that's all.  No wind in the nw eyewall isn't what I expected.

[Intensewind002]

8 minutes ago, BretWx said:

This looks a bit.... like something we've seen before.... 

Never use the NAM for hurricanes…

[a5ehren]

Kinda looks like it is having trouble wrapping the deep convection around the eye. Surprised.

[WxWatcher007]

Dropsonde was 972mb with 5kt wind

[Kevin Reilly]

I see some limiting factors dry air north of the Yucatan and also an area of shear moving SE with the upper level low over the NE Gulf sliding south.  I am wondering if the dry air to the west keeps things in check a bit and the upper air low over the NE Gulf forces Idalia further southeast track but on a NE trajectory towards say Sarasota to Tarpon Springs area guess time will tell. 

 

Above it what I said last night around 9:30 PM

I don't think the second part will be right obviously, but the dry air as a limiting factor for intensity could.

[CoastalWx]

4 minutes ago, a5ehren said:

Kinda looks like it is having trouble wrapping the deep convection around the eye. Surprised.

Hurricanes are fickle. The environment has to be pristine for upper end 4-5s. 

[CoastalWx]

Just now, Kevin Reilly said:

I see some limiting factors dry air north of the Yucatan and also an area of shear moving SE with the upper level low over the NE Gulf sliding south.  I am wondering if the dry air to the west keeps things in check a bit and the upper air low over the NE Gulf forces Idalia further southeast track but on a NE trajectory towards say Sarasota to Tarpon Springs area guess time will tell. 

 

Above it what I said last night around 9:30 PM

There is no way it goes that far south. 

[WxWatcher007]

Continuing the pass into the SE eyewall, recon found FL winds between 84-91kts. That’s legit. 

[LongBeachSurfFreak]

1 minute ago, WxWatcher007 said:

Continuing the pass into the SE eyewall, recon found FL winds between 84-91kts. That’s legit. 

Pretty hard to not find at least some decent winds with a 970 pressure. Like others have said it takes near perfect conditions to creat a 5. The classic is Katrina going from a cat one to a 5 while passing right over this same area. 

[Covidea]

26 minutes ago, WxWatcher007 said:

Ok, confusion cleared up. Recon IS in the air and is starting to fly toward the center in a likely NW to SE pass. 

Coming out of Ft. Lauderdale

[WxWatcher007]

First VDM--eyewall open in the NW

 

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 29th day of the month at 20:26Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF97-5304
Storm Name: Idalia
Storm Number & Year: 10 in 2023 (flight in the North Atlantic basin)
Mission Number: 11
Observation Number: 04 ( See all messages of this type for this mission. )

A. Time of Center Fix: 29th day of the month at 20:21:40Z
B. Center Fix Coordinates: 25.91N 84.82W
B. Center Fix Location: 190 statute miles (306 km) to the WSW (255°) from Fort Myers, FL, USA.
C. Minimum Height at Standard Level: 2,879m (9,446ft) at 700mb
D. Minimum Sea Level Pressure: 972mb (28.71 inHg)
E. Dropsonde Surface Wind at Center: From 205° at 5kts (From the SSW at 6mph)
F. Eye Character: Open in the northwest
G. Eye Shape & Diameter: Circular with a diameter of 25 nautical miles (29 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: 5 nautical miles to the NW (312°) of center fix at 20:20:00Z
J. Maximum Flight Level Wind Inbound: From 34° at 53kts (From between the NNE and NE at 61.0mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 5 nautical miles to the NW (312°) of center fix at 20:20:00Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 69kts (79.4mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 14 nautical miles (16 statute miles) to the SE (136°) of center fix at 20:25:30Z
N. Maximum Flight Level Wind Outbound: From 237° at 91kts (From the WSW at 104.7mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 18 nautical miles (21 statute miles) to the SE (135°) of center fix at 20:26:30Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 14°C (57°F) at a pressure alt. of 3,067m (10,062ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 15°C (59°F) at a pressure alt. of 3,068m (10,066ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 14°C (57°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 Levels (surface & flight level centers within 5nm of each other): Surface and 700mb
T. Navigational Fix Accuracy: 0.02 nautical miles
T. Meteorological Accuracy: 1 nautical mile

Remarks Section:
 

Maximum Flight Level Wind: 91kts (~ 104.7mph) which was observed 18 nautical miles (21 statute miles) to the SE (135°) from the flight level center at 20:26:30Z

[MANDA]

1 minute ago, LongBeachSurfFreak said:

Pretty hard to not find at least some decent winds with a 970 pressure. Like others have said it takes near perfect conditions to creat a 5. The classic is Katrina going from a cat one to a 5 while passing right over this same area. 

You knew Katrina meant business when it exited the SW coast of FL more organized than when it came in on the SE coast.  That storm just had the look from the get go.  Classic "brown ocean" intensification while tracking across the Everglades.

[NJwx85]

First SVR warning of the day here, just SW in Osceola County. Saw some good structure 

[GaWx]

31 minutes ago, CCHurricane said:

One for the history books if Idalia makes landfall as a major. Also looks like relative to history, the area has been long overdue. 

Apalachee Bay Hurricane Landfalls

• Hermine (2016) - Category 1
• Alma (1966) - Category 1 
• Unnamed (1941) - Category 1
• Unnamed (1935) - Category 2
• Unnamed (1899) - Category 2
• Unnamed (1886) - Category 2
• Unnamed (1886) - Category 2
• Unnamed (1882) - Category 1
• Unnamed (1880) - Category 1
• Unnamed (1873) - Category 1
• Unnamed (1867) - Category 1
• Unnamed (1852) - Category 2

Maybe this won't end up as a major H landfall. Fingers crossed! Perhaps their climo says that there are geographic factors that make it extremely difficult and that that will come into play for Idalia. Thoughts?

[MANDA]

Idalia is trying hard based on satellite and radar.  Really thought by this time (late afternoon) we would have started to see an eye starting to pop and clear out on satellite.  So far recon is not overly impressive. 

[WxWatcher007]

Having an open eyewall stunts intensification, but it doesn't stop it of course. I'm interested in what recon finds in the other three quadrants. It's clearly intensifying based on that SE pass and IR. It could also be the case that the winds are trying to catch up to the pressure falls. NHC may up the winds at 5pm just like they did earlier on the assumption the NE quad will produce. 

[WxWatcher007]

Welp  

5:00 PM EDT Tue Aug 29
Location: 26.1°N 84.8°W
Moving: N at 16 mph
Min pressure: 972 mb
Max sustained: 100 mph

CHANGES WITH THIS ADVISORY:

A Hurricane Watch has been issued from the mouth of the St. Mary's
River northward to Edisto Beach.

A Storm Surge Watch has been issued from Beaufort Inlet to Drum
Inlet, North Carolina, as well as the Neuse and Pamlico Rivers.

A Tropical Storm Warning has been issued from South Santee River
northward to Surf City, North Carolina.  A Tropical Storm Watch has
been issued north of Surf City to the North Carolina/Virginia
border, including Pamlico and Albemarle Sounds.

The Hurricane Watch from Englewood to the Middle of Longboat Key
has been discontinued.

The Storm Surge Watch has been discontinued south of Bonita Beach,
Florida.

[StantonParkHoya]

They just said 100, but that’s not based on findings

[Rtd208]

Idalia is a CAT 2 now 100 mph winds

[CoastalWx]

100? Could have fooled me.

[Normandy]

The first pass is interesting because it’s suggestive of a storm that is extremely imbalanced but not necessarily weak.  Large swatch of strong flight level winds and the wind gradient was steep exiting into the SE eyewall.  As this burst continues will be interesting to see winds in the other quads.  

[the_other_guy]

Wasn’t this always supposed to be a weaker hurricane that had sheer issues holding back intensification? I remember saying this like four days ago. I know it got hyped up in the last 48 hours but this is playing out exactly as planned.

[Rtd208]

Just now, CoastalWx said:

100? Could have fooled me.

I am a bit suprised based on recon findings. 

[cptcatz]

There's a nasty feeder band about to come through my house in Boca Raton.  Should get interesting.

[GaWx]

1 minute ago, WxWatcher007 said:

Welp  

5:00 PM EDT Tue Aug 29
Location: 26.1°N 84.8°W
Moving: N at 16 mph
Min pressure: 972 mb
Max sustained: 100 mph

CHANGES WITH THIS ADVISORY:

A Hurricane Watch has been issued from the mouth of the St. Mary's
River northward to Edisto Beach.

A Storm Surge Watch has been issued from Beaufort Inlet to Drum
Inlet, North Carolina, as well as the Neuse and Pamlico Rivers.

A Tropical Storm Warning has been issued from South Santee River
northward to Surf City, North Carolina.  A Tropical Storm Watch has
been issued north of Surf City to the North Carolina/Virginia
border, including Pamlico and Albemarle Sounds.

The Hurricane Watch from Englewood to the Middle of Longboat Key
has been discontinued.

The Storm Surge Watch has been discontinued south of Bonita Beach,
Florida.

Ouch! Hurricane watch GA and lower SC coast. Hope this is overdone but it has been a worry. Hopefully the struggles of the storm that have been mentioned here are actually going to keep it from reaching major status. But it isn't looking good right now.

[WxSynopsisDavid]

I been told they are using drones to also recon Idalia. That data set is not available to the public. It’s possible they got the 100mph reading using other methods instead of Recon Hunters.

[hlcater]

91kts FL is what they based it on, along with the pretense that the NE quad has not been sampled yet. Decent strengthening from the last pass, but perhaps not as rapid as models had indicated. However, the storm is in good shape for more robust strengthening tonight. Still think an intensity of 110-115kts is a pretty reasonable guess for landfall.

[WxWatcher007]

Hurricane Idalia Discussion Number  13
NWS National Hurricane Center Miami FL       AL102023
500 PM EDT Tue Aug 29 2023

The first stages of an eye have been taking shape in visible
satellite imagery.  The hurricane has a relatively small Central
Dense Overcast and a prominent band of deep convection extending
over the eastern semicircle, reaching across the Florida peninsula
southward across western Cuba.  An Air Force Reserve Hurricane 
Hunter aircraft just measured a peak 700-mb flight-level wind of 91 
kt with the pressure falling to 972 mb.  The initial intensity is 
therefore set at 85 kt.

Idalia is moving faster toward the north, or 360/14 kt, between a
mid-level trough over the northwestern Gulf of Mexico and a
subtropical ridge over the Greater Antilles.  Idalia is expected to
continue moving northward and turn north-northeastward as it
approaches the Big Bend region of Florida during the next 12-24
hours.  There is very little spread among the track guidance, and
the NHC official forecast has been placed very close to the HCCA
and TVCX consensus aids during the first 24 hours.  This has
resulted in a westward shift of about 20-25 n mi compared to the
previous forecast, although it should be stressed that additional
shifts to the track will be possible until the center reaches land.

After landfall, Idalia is expected to turn toward the northeast and
then east, moving near or along the coast of Georgia and the
Carolinas in 36-48 hours.  Uncertainty in the track forecast is
still quite large after 48 hours, with many of the global models
turning Idalia southward, while some of the regional hurricane
models still show the storm moving out to sea.  As a result, the
official track forecast continues to show slow motion on days 4 and
5.

The 12-hour intensity forecast shows a 100-kt major hurricane.  It
is imperative to realize that Idalia is expected to continue
strengthening beyond that time, possibly close to the 110 kt shown
in the previous forecast, before the center reaches land.
Weakening is expected after landfall, but due to the system's
expected fast motion, it is possible that Idalia could maintain
hurricane intensity as it moves across southern Georgia and 
approaches the coasts of Georgia and South Carolina.  After 
Idalia's center moves offshore over the western Atlantic, strong 
shear is likely to limit re-intensification, and the official 
forecast essentially flatlines the intensity on days 2-5.


KEY MESSAGES:

1. Catastrophic impacts from storm surge inundation of 10 to 15 feet 
above ground level and destructive waves are expected somewhere 
between Aucilla River and Yankeetown, Florida. Life-threatening 
storm surge inundation is likely elsewhere along portions of the 
Florida Gulf Coast where a Storm Surge Warning is in effect.  
Residents in these areas should follow any advice given by local 
officials.

2. There is the potential for destructive life-threatening winds 
where the core of Idalia moves onshore in the Big Bend region of 
Florida, with hurricane conditions expected elsewhere in portions of 
the Hurricane Warning area along the Florida Gulf Coast. Strong 
winds will also spread inland across portions of northern Florida 
and southern Georgia near the track of the center of Idalia where 
Hurricane Warnings are in effect. Residents in these areas should be 
prepared for long-duration power outages. Damaging hurricane-force 
winds are possible in portions of eastern Georgia and southeastern 
South Carolina where Hurricane Watches are in effect. 

3. Areas of flash, urban, and moderate river flooding, with locally 
considerable impacts, are expected across the Florida Big Bend, 
central Georgia and South Carolina, through eastern North Carolina 
later tonight into Thursday.



FORECAST POSITIONS AND MAX WINDS

INIT  29/2100Z 26.1N  84.8W   85 KT 100 MPH
 12H  30/0600Z 28.3N  84.5W  100 KT 115 MPH
 24H  30/1800Z 31.0N  82.9W   75 KT  85 MPH...INLAND
 36H  31/0600Z 32.9N  80.2W   50 KT  60 MPH...INLAND
 48H  31/1800Z 33.9N  77.1W   45 KT  50 MPH...OVER WATER
 60H  01/0600Z 33.8N  74.2W   45 KT  50 MPH
 72H  01/1800Z 33.3N  71.8W   45 KT  50 MPH
 96H  02/1800Z 32.3N  69.6W   45 KT  50 MPH
120H  03/1800Z 31.7N  69.0W   45 KT  50 MPH

$$
Forecaster Berg

[CoastalWx]

So a random 91kt FL wind at 700mb translates to 100mph at the surface? Not sure how I feel about that. 

[GaWx]

From 5PM NHC discussion: "This has
resulted in a westward shift of about 20-25 n mi compared to the
previous forecast"

 This makes sense based on 12Z model consensus.