Absolute Vorticity

Click on this link to view satellite images. This system is definitely getting its act together. At last check, NHC now has it maxing out at 125 mph!


https://www.star.nesdis.noaa.gov/goes/f ... d=AL102023


Outer bands are already impacting Tampa. Here is the radar loop out of NWS Tampa.


https://radar.weather.gov/station/KTBW/standard

As of 2pm... 90 mph winds now moving N at 15 mph. Pressure down to 974 MB.

Hurricane Idalia Intermediate Advisory Number 12A
NWS National Hurricane Center Miami FL AL102023
200 PM EDT Tue Aug 29 2023

...IDALIA'S SQUALLS OVERSPREADING PORTIONS OF THE LOWER FLORIDA KEYS
AND THE SOUTHWESTERN COAST OF FLORIDA...
...LIFE-THREATENING STORM SURGE AND HURRICANE CONDITIONS EXPECTED
ALONG PORTIONS OF THE GULF COAST OF FLORIDA TONIGHT AND WEDNESDAY...


SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...25.2N 84.9W
ABOUT 130 MI...210 KM WNW OF THE DRY TORTUGAS
ABOUT 240 MI...390 KM SW OF TAMPA FLORIDA
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...974 MB...28.76 INCHES

Storm surge now predicted to be 12 feet or higher in the Big Bend area. Not good...


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 Yankeetown, FL...10-15 ft
Yankeetown to Chassahowitzka, FL...7-11 ft
Ochlockonee River, FL to Aucilla River, FL...7-11 ft
Chassahowitzka, FL to Anclote River, FL...6-9 ft
Anclote River, FL to Middle of Longboat Key, FL...4-7 ft
Tampa Bay...4-7 ft
Carrabelle, FL to Ochlockonee River, FL...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 Carrabelle, FL...3-5 ft
Mouth of the St. Mary's River to South Santee, SC...2-4 ft
South Santee, SC to Surf City, NC...1-3 ft
Chokoloskee, FL to East Cape Sable, FL...1-3 ft
Flagler/Volusia County Line, FL to Mouth of St. Mary's River...1-3 ft
Indian Pass to Mexico Beach...1 to 3 ft.
Florida Keys...1-2 ft

----

Cat 2 now...

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

Corrected Tropical Storm Warning area


...IDALIA NOW A CATEGORY 2 HURRICANE...
...LIFE-THREATENING STORM SURGE AND HURRICANE CONDITIONS EXPECTED
ALONG PORTIONS OF THE GULF COAST OF FLORIDA TONIGHT AND WEDNESDAY...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...26.1N 84.8W
ABOUT 195 MI...310 KM SW OF TAMPA FLORIDA
ABOUT 300 MI...480 KM S OF TALLAHASSEE FLORIDA
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...972 MB...28.71 INCHES

----

BULLETIN
Hurricane Idalia Advisory Number 14
NWS National Hurricane Center Miami FL AL102023
1100 PM EDT Tue Aug 29 2023

...IDALIA STILL STRENGTHENING...
...FORECAST TO BE AN EXTREMELY DANGEROUS CATEGORY 4 INTENSITY AT
LANDFALL...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...27.7N 84.5W
ABOUT 125 MI...200 KM W OF TAMPA FLORIDA
ABOUT 185 MI...300 KM S OF TALLAHASSEE FLORIDA
MAXIMUM SUSTAINED WINDS...110 MPH...175 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...958 MB...28.29 INCHES

No way it’s a 4 at landfall , guaranteed. Wind obs atm are minimal and she’s been weakening considerably over the last couple of hours

She did max out at 130 mph as of the 5am advisory, but as of about 7am, she is definitely weakening now as Bgoney mentioned. Still a dangerous and powerful storm with 10-15 foot storm surge likely.

tron777 wrote: ↑Wed Aug 30, 2023 7:29 am She did max out at 130 mph as of the 5am advisory, but as of about 7am, she is definitely weakening now as Bgoney mentioned. Still a dangerous and powerful storm with 10-15 foot storm surge likely.

Great Post. Many times these hurricanes will hit a certain cat for a shot time and that seems to be the case here. The storm surge is the biggest threat to those areas. Yes strong winds for a short period of time and heavy rains as well. The good thing is not many folks live near the beach in that area though still have houses on the beach in certain places.

I’m looking at observed winds on the ground, so far the highest I’ve seen is mid 80s

WS National Hurricane Center Miami FL AL102023
700 AM EDT Wed Aug 30 2023

...CATASTROPHIC STORM SURGE AND DESTRUCTIVE WINDS OCCURRING IN THE
FLORIDA BIG BEND REGION...
...7 AM POSITION UPDATE...

Radar and Air Force Reserve Hurricane Hunter aircraft data
indicate that an eyewall replacement cycle has begun. Idalia's
maximum sustained winds are now estimated near 125 mph (205 km/h)
with higher gusts. This change in wind speed does not diminish the
threat of catastrophic storm surge and damaging winds.

The estimated minimum pressure indicated by Air Force Reserve
Hurricane Hunter aircraft data is 947 mb (27.96 inches).

Within the past hour, a C-MAN station on Cedar Key measured
sustained winds of 47 mph (76 km/h), with a gust to 55 mph (88
km/h), and a Weatherflow station at Apalachee Bay measured a
sustained wind of 43 mph (69 km/h), with a gust to 55 mph (88
km/h). A Florida Coastal Monitoring Program tower near Lake City,
Florida, recently reported a wind gust to 51 mph (82 km/h).

A NOAA National Ocean Service tide gauge at Cedar Key, Florida,
recently reported a water level of 5.2 feet above mean higher high
water, which is an approximation of inundation in that area.

SUMMARY OF 700 AM EDT...1100 UTC...INFORMATION
----------------------------------------------
LOCATION...29.6N 83.8W
ABOUT 55 MI...90 KM NW OF CEDAR KEY FLORIDA
ABOUT 65 MI...105 KM SSE OF TALLAHASSEE FLORIDA
MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...947 MB...27.96 INCHES

$$
Forecaster Brown/Stevenson

Within the past hour, a C-MAN station at Keaton Beach, Florida,
measured sustained winds of 61 mph (98 km/h), with a gust to 77 mph
(124 km/h). A Florida Coastal Monitoring Program tower located
southwest of Hampton Springs, Florida, recently reported a wind gust
of 68 mph (109 km/h).

Water levels along the coast of the Florida Big Bend are rising
rapidly. A NOAA National Ocean Service tide gauge at Cedar Key,
Florida, recently reported a water level of 5.9 feet above mean
higher high water, which is an approximation of inundation in that
area.

SUMMARY OF 745 AM EDT...1145 UTC...INFORMATION

It looks like around 8am ET, she made landfall near the Tallahassee River.

Latest statement from NWS Tallahassee from earlier this morning.

https://www.nhc.noaa.gov/text/WTUS82-KTAE.shtml

Bgoney wrote: ↑Wed Aug 30, 2023 6:30 am No way it’s a 4 at landfall , guaranteed. Wind obs atm are minimal and she’s been weakening considerably over the last couple of hours

Thankful that it didn't reach Cat 4 as of course a 3 is bad enough. Prayers and thoughts with all those in the path.

MVWxObserver wrote: ↑Wed Aug 30, 2023 8:50 am

Bgoney wrote: ↑Wed Aug 30, 2023 6:30 am No way it’s a 4 at landfall , guaranteed. Wind obs atm are minimal and she’s been weakening considerably over the last couple of hours

Thankful that it didn't reach Cat 4 as of course a 3 is bad enough. Prayers and thoughts with all those in the path.

Of course, still searching for an observed landfall sustained winds of 100 , let alone 130 need for a cat 4

Per the NHC, this looks to be the official time and landfall location:

Idalia made landfall along the coast of Florida's Big Bend near Keaton Beach around 7:45 a.m. ET, the National Hurricane Center said.

Source: https://www.nbcnews.com/news/weather/li ... rcna102478

Per this article: https://www.foxweather.com/weather-news ... torm-surge The top wind gust I could find so far is at Keaton Beach - 83 mph.

Hurricane Idalia Advisory Number 16...Corrected
NWS National Hurricane Center Miami FL AL102023
1100 AM EDT Wed Aug 30 2023

Corrected watch/warning section

...CENTER OF IDALIA CROSSING INTO SOUTHERN GEORGIA...
...HIGH WATER LEVELS CONTINUE ALONG THE GULF COAST OF FLORIDA...


SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...30.6N 83.2W
ABOUT 15 MI...20 KM SSE OF VALDOSTA GEORGIA
ABOUT 165 MI...265 KM SW OF SAVANNAH GEORGIA
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...NNE OR 30 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...971 MB...28.68 INCHES

Good Afternoon and looks like the system is making its way to the Atlantic Ocean. Bgoney brought up a point this morning where he believed the winds were never in the CAT 4 area. I can't say either way but sometimes just because you have a Cat 4 instead of a Cat 2 does not mean the Cat 4 was worse. This system is moving in and out quickly and yes the surge was big because if where its located but they also get big surges with just a tropical storm though not this big of a surge. What happens in area where the Hurricane and lets say a Cat 2 stays just off shore but lashes a coastline for over 24 hours. Imo that is much worse as you are putting so much pressure on buildings,trees,etc. So yes the headline is CAT 4 but sometimes that does not tell the whole story.

Heck, we have seen small snow amounts under 1 inch cause more problem than a 6 inch snow. So many other things involved and just because the number may be bigger does not always tell us the whole story once again.

Wonderful post Tim! Very well stated. Now that I think of it, that is probably the point Bgoney was trying to make this morning as well.

An interesting stat that BG tweeted (or X'ed I should say now LOL) about this system. The stat is of course is coming from the hurricane center and also likely from the NWS in Tallahassee.

As of 2pm, Idalia is down to 75 mph moving across SE Georgia at 20 mph (moving NE). It is expected to move towards the SC Coast tonight and be off the NC Coast sometime tomorrow.

tpweather wrote: ↑Wed Aug 30, 2023 12:57 pm Good Afternoon and looks like the system is making its way to the Atlantic Ocean. Bgoney brought up a point this morning where he believed the winds were never in the CAT 4 area. I can't say either way but sometimes just because you have a Cat 4 instead of a Cat 2 does not mean the Cat 4 was worse. This system is moving in and out quickly and yes the surge was big because if where its located but they also get big surges with just a tropical storm though not this big of a surge. What happens in area where the Hurricane and lets say a Cat 2 stays just off shore but lashes a coastline for over 24 hours. Imo that is much worse as you are putting so much pressure on buildings,trees,etc. So yes the headline is CAT 4 but sometimes that does not tell the whole story.

Heck, we have seen small snow amounts under 1 inch cause more problem than a 6 inch snow. So many other things involved and just because the number may be bigger does not always tell us the whole story once again.

Excellent points by both Bgoney and Tim!

Hi Tim,

Speaking of snow amounts under 1 inch or even at an inch e.g. I remember from my days in Raleigh, NC where in a January storm an inch fell but the NCDOT was an epic fail because they delayed on pre-treating routes and so the afternoon / evening rush hour was a total nightmare and some kids aboard school buses ended up having to stay overnight in their schools. My Dad was stuck on a snow covered-turned ice rink on a road trying to get home from his job with the State of NC water quality dept and he was stranded in stalled traffic and didn't get home until around 2 o'clock the next morning! Usually the NCDOT was on top of things during winter events but that memorable storm will be forever etched in the memories of my folks and I. And to think it was just a mere 1 inch of the white stuff. At the end though the NCDOT and Wake County learned a big lesson re pre-treating thoroughfares before the snow began falling. Also there wasn't any rain or mix in the forecast either for that system.