Major Hurricane Irma

[Random Chaos]

SFMR found 117kt winds NW quadrant and 111kt winds SE quadrant. First pass to find >110kt on both inbound and outbound leg.

[JasonOH]

2 minutes ago, Griizzcoat said:

Does those include the new data packages??

18z includes the special soundings and any data collected before 18z.

[Hoosier]

3 minutes ago, SN_Lover said:

Notice this is further North from Cuba than the 18z. More trends like this could mean FL gets missed completely and anywhere from GA to Maine gets hit with her full might.  

It tightened from 18z... some northern tracks came south and southern tracks came north.  Here is 18z for comparison

[SN_Lover]

3 minutes ago, Hoosier said:

It tightened from 18z... some northern tracks came south and southern tracks came north.  Here is 18z for comparison

Which tracks at hour 120 came south? 

[MattPetrulli]

I can't decide which coast of FL Irma goes up would be more catastrophic than the other. Both very popular, surge prone areas.

[ncforecaster89]

9 minutes ago, JasonOH said:

18z includes the special soundings and any data collected before 18z.

Don't think that's accurate as the data was actually collected after 18z.   It's the 00z runs that will contain the aforementioned data.     

[thewxmann]

2 minutes ago, MattPetrulli said:

I can't decide which coast of FL Irma goes up would be more catastrophic than the other. Both very popular, surge prone areas.

West Coast is far more surge prone but less population till you get up to Naples/Ft. Meyers north to Cedar Key. Pick your poison.

[Wow]

Trend loop of the hurricane models 

[Hoosier]

4 minutes ago, SN_Lover said:

Which tracks at hour 120 came south? 

CTCI and COTI.  Other than that, harder to tell.

[HIPPYVALLEY]

1 minute ago, MattPetrulli said:

I can't decide which coast of FL Irma goes up would be more catastrophic than the other. Both very popular, surge prone areas.

Eye wall riding just inside E Coast for the length of the peninsula, from Miami to Savannah, would be pretty catastrophic.

[andyhb]

Dropsonde with 140-145+ kt winds at 920-930 mb in the SE eyewall.

[JasonOH]

Just now, ncforecaster89 said:

Don't think that's accurate as the data was actually collected after 18z.   It's the 00z runs that will contain the achievement data.   

If it's 18z it's launched about 1hour before, and the data would be integrated in like any 0/12z sounding, but with the 18z models.  For the data to be in 18z models it had to be from before 18z

[ncforecaster89]

3 minutes ago, MattPetrulli said:

I can't decide which coast of FL Irma goes up would be more catastrophic than the other. Both very popular, surge prone areas.

I'd suggest a track hugging the Fl east coast, whereby it retains MH intensity and making a direct landfall in the Carolina's.     

[bdgwx]

3 minutes ago, ncforecaster89 said:

Don't think that's accurate as the data was actually collected after 18z.   It's the 00z runs that will contain the aforementioned data.     

AVNI is the 18Z GFS and TVCN contains an 18Z GFS weighting so at least those 2 tracks should contain the 18Z RAOBS.

[donsutherland1]

With Irma having tracked generally west-southwestward for much of the day before turning to the west, it has reached a position with a much greater climatological risk of landfall. Since 1851, 32 hurricanes have passed within 100 miles of Irma's 8 pm position of 16.7°N 55.0°W. 13/32 or 41% made U.S. landfall and 7 of the 13 (54%) storms that made landfall made their first landfall in Florida. The majority of such hurricanes were major hurricanes at U.S. landfall. The following details follow from the above sample:

Classification of Hurricanes at First U.S. Landfall:
Category 1: 8%
Category 2: 15%
Category 3: 31%
Category 4: 46%

First U.S. Landfall at Florida:
Hurricane #4 (1871): Category 3
1926 “Great Miami Hurricane:” Category 4
1928 “Lake Okeechobee Hurricane:” Category 4
Hurricane #4 (1947): Category 4
Donna (1960): Category 4
Inez (1966): Category 1
Georges (1998): Category 2

Considering a blend of the climatology associated with hurricanes passing in the vicinity where Irma has tracked and the ensembles/operational guidance, my thinking is that U.S. landfall is now a 75% probability. The area of greatest risk has shifted south to Florida with the wider Florida-North Carolina region at highest risk. Small possibilities exist for Irma to enter the Gulf of Mexico and then track to Alabama or westward or for Irma to head for the Virginia-New England area based largely on climatology. 
 

[winterymix]

5 minutes ago, el_sordo said:

Thanks for posting this.

 

Can anyone sum up what factors are likely to affect the timing of Irma's impacts, and the rate it moves north? i.e. atmospheric dynamics or interaction with land?  Do the models have much skill or consistency with predicting this?

I'm flying int'l from CLT with a connection in Atlanta on 9/12. 

You've got to wait until about 72 hours before land fall.

As of now, it makes landfall just south of Miami, scrapes the coast and then moves into the GA coast east of Macon.

The only thing that improves a forecast right now, 5 to 6 days out are model trends; what direction are the model shifts?

[HIPPYVALLEY]

1 minute ago, donsutherland1 said:

With Irma having tracked generally west-southwestward for much of the day before turning to the west, it has reached a position with a much greater climatological risk of landfall. Since 1851, 32 hurricanes have passed within 100 miles of Irma's 8 pm position of 16.7°N 55.0°W. 13/32 or 41% made U.S. landfall and 7 of the 13 storms that made landfall made their first landfall in Florida. The majority of such hurricanes were major hurricanes at U.S. landfall.

Classification of Hurricanes at First U.S. Landfall:
Category 1: 8%
Category 2: 15%
Category 3: 31%
Category 4: 46%

First U.S. Landfall at Florida:
Hurricane #4 (1871): Category 3
1926 “Great Miami Hurricane:” Category 4
1928 “Lake Okeechobee Hurricane:” Category 4
Hurricane #4 (1947): Category 4
Donna (1960): Category 4
Inez (1966): Category 1
Georges (1998): Category 2

Considering a blend of the climatology associated with hurricanes passing in the vicinity where Irma has tracked and the ensembles/operational guidance, my thinking is that U.S. landfall is now a 75% probability. The area of greatest risk has shifted south to Florida with the wider Florida-North Carolina region at highest risk. Small possibilities exist for Irma to enter the Gulf of Mexico and then track to Alabama or westward or for Irma to head for the Virginia-New England area based largely on climatology. 
 

Your statistical analysis are a gift to this board!

[el_sordo]

Just now, winterymix said:

You've got to wait until about 72 hours before land fall.

As of now, it makes landfall just south of Miami, scrapes the coast and then move into the GA coast east of Macon.

The only thing that improves a forecast right now, 5 to 6 days out are model trends; what direction are the model shifts?

With all else equal, would its forward speed moving straight up the spine of FL be faster or slower than than if the eye stays offshore?

[SnowLover22]

8 minutes ago, donsutherland1 said:

With Irma having tracked generally west-southwestward for much of the day before turning to the west, it has reached a position with a much greater climatological risk of landfall. Since 1851, 32 hurricanes have passed within 100 miles of Irma's 8 pm position of 16.7°N 55.0°W. 13/32 or 41% made U.S. landfall and 7 of the 13 (54%) storms that made landfall made their first landfall in Florida. The majority of such hurricanes were major hurricanes at U.S. landfall. The following details follow from the above sample:

Classification of Hurricanes at First U.S. Landfall:
Category 1: 8%
Category 2: 15%
Category 3: 31%
Category 4: 46%

First U.S. Landfall at Florida:
Hurricane #4 (1871): Category 3
1926 “Great Miami Hurricane:” Category 4
1928 “Lake Okeechobee Hurricane:” Category 4
Hurricane #4 (1947): Category 4
Donna (1960): Category 4
Inez (1966): Category 1
Georges (1998): Category 2

Considering a blend of the climatology associated with hurricanes passing in the vicinity where Irma has tracked and the ensembles/operational guidance, my thinking is that U.S. landfall is now a 75% probability. The area of greatest risk has shifted south to Florida with the wider Florida-North Carolina region at highest risk. Small possibilities exist for Irma to enter the Gulf of Mexico and then track to Alabama or westward or for Irma to head for the Virginia-New England area based largely on climatology. 
 

We need more posters like you. 

[Jackstraw]

One thing the islands have going for them is it looks like Cat 2 and higher surface winds are confined very close to the center, maybe within 10 miles atm.  If the storm can remain fairly compact as it is now over the next 24-36 hours and stay on the forecast track maybe Anguilla, perhaps to a bit of a lesser extent Antigua and St. Martin get a pretty good dose but the others may dodge a bullet.  That's a big if, barring any wobbles or rapid expansion of the wind field or a continuation west a little longer than forecast.  An ERC early tomorrow evening could also be a blessing.  

[Random Chaos]

Hurricane hunter radar loop:

https://twitter.com/TropicalATL/status/904885078702006272

[winterymix]

3 minutes ago, el_sordo said:

With all else equal, would its forward speed moving straight up the spine of FL be faster or slower than than if the eye stays offshore?

I think the forward speed and path will be influenced by the 500 mb pattern, 500_vort_ht.

You can see this at weather.gov and at the top, click on information and then on forecast models, model guidance

and GFS  NAMER and then 500_vort_ht  and run the loop.  What seems to be happening is that a large HIGH over the Atlantic

keeps the system moving west and WSW.  A large trough moves across the US and at first exerts no effect on the hurricane.

Later in the period, the large Atlantic high moves east and the trough moves NE and the hurricane turns north/poleward in

response to the lack of other steering influences aside from the retreating atlantic high and the progressive mid-latitude trough.

The speed of those items will influence the forward speed of the hurricane.

[AfewUniversesBelowNormal]

20 minutes ago, donsutherland1 said:

With Irma having tracked generally west-southwestward for much of the day before turning to the west, it has reached a position with a much greater climatological risk of landfall. Since 1851, 32 hurricanes have passed within 100 miles of Irma's 8 pm position of 16.7°N 55.0°W. 13/32 or 41% made U.S. landfall and 7 of the 13 (54%) storms that made landfall made their first landfall in Florida. The majority of such hurricanes were major hurricanes at U.S. landfall. The following details follow from the above sample:

Classification of Hurricanes at First U.S. Landfall:
Category 1: 8%
Category 2: 15%
Category 3: 31%
Category 4: 46%

First U.S. Landfall at Florida:
Hurricane #4 (1871): Category 3
1926 “Great Miami Hurricane:” Category 4
1928 “Lake Okeechobee Hurricane:” Category 4
Hurricane #4 (1947): Category 4
Donna (1960): Category 4
Inez (1966): Category 1
Georges (1998): Category 2

Considering a blend of the climatology associated with hurricanes passing in the vicinity where Irma has tracked and the ensembles/operational guidance, my thinking is that U.S. landfall is now a 75% probability. The area of greatest risk has shifted south to Florida with the wider Florida-North Carolina region at highest risk. Small possibilities exist for Irma to enter the Gulf of Mexico and then track to Alabama or westward or for Irma to head for the Virginia-New England area based largely on climatology. 
 

With the blanket of warming that has happened all over the globe in the last 20 years, I think we can upgrade all climo stats to lower pressureskew these days. Maybe a whole category. In other words, Cat 3 = Cat 4, etc. Plus this is one the best looking hurricanes in the beginning stages maybe ever.

[NaoPos]

Raw t#'s @6.6 currently

[hypatia]

6 minutes ago, donsutherland1 said:

With Irma having tracked generally west-southwestward for much of the day before turning to the west, it has reached a position with a much greater climatological risk of landfall. Since 1851, 32 hurricanes have passed within 100 miles of Irma's 8 pm position of 16.7°N 55.0°W. 13/32 or 41% made U.S. landfall and 7 of the 13 (54%) storms that made landfall made their first landfall in Florida. The majority of such hurricanes were major hurricanes at U.S. landfall. The following details follow from the above sample:

Classification of Hurricanes at First U.S. Landfall:
Category 1: 8%
Category 2: 15%
Category 3: 31%
Category 4: 46%

First U.S. Landfall at Florida:
Hurricane #4 (1871): Category 3
1926 “Great Miami Hurricane:” Category 4
1928 “Lake Okeechobee Hurricane:” Category 4
Hurricane #4 (1947): Category 4
Donna (1960): Category 4
Inez (1966): Category 1
Georges (1998): Category 2

Considering a blend of the climatology associated with hurricanes passing in the vicinity where Irma has tracked and the ensembles/operational guidance, my thinking is that U.S. landfall is now a 75% probability. The area of greatest risk has shifted south to Florida with the wider Florida-North Carolina region at highest risk. Small possibilities exist for Irma to enter the Gulf of Mexico and then track to Alabama or westward or for Irma to head for the Virginia-New England area based largely on climatology. 
 

 

An additional concern for this storm, if it takes a track similar to 1926 Miami or 1928 Okeechobee hurricanes, is the Herbert Hoover Dike on the southern end of Lake Okeechobee.  The dike has been known to be in a state of disrepair for quite some time; only recently has Gov. Scott pushed for funding to repair the dike.  The motivation for the funding revolves primarily around preventing more discharges of algae-contaminated water into the intracoastal waterways (which has an impact on tourism).  The project, so far, is badly underfunded: http://www.sun-sentinel.com/local/palm-beach/fl-pn-lake-okeechobee-money-legislature-20170614-story.html

I worry about the possibility of another flooding disaster, like what happened in 1928 and to a lesser extent in 1926.  Irma, with its large wind field and possible landfalling category 4+ strength, is reminiscent of both of these storms.  If the track is right, there is the potential for a catastrophic storm surge to be generated on Lake Okeechobee.  Folks living in inland places along the lake, like Belle Glade and Clewiston, should pay close attention.

 

[NJwx85]

ADT estimates just increased to 122kts, that supports the latest advisory of 140mph, however since that's been running a little below recon it's probably a tad stronger. Looks like recon is heading to sample the NE quadrant now.

[lakeeffectkid383]

ADT estimate down to 942mb, and 122kt.

[Sportybx]

2 minutes ago, NJwx85 said:

ADT estimates just increased to 122kts, that supports the latest advisory of 140mph, however since that's been running a little below recon it's probably a tad stronger. Looks like recon is heading to sample the NE quadrant now.

Isn't it just going to get stronger and stronger the more it moves into the warmer water . Wouldn't be surprised if it opened up a bit and grew in size 

[SharonA]

59 minutes ago, terdferguson said:

This.  No need to evacuate now.  But you should get all your supplies and have your evacuation plan in place (where are you going to go?).

Response to other post about supplies in s fla:  Yes there is already a run on supplies.  Publix was out of water today.  People in s fla prepare early.  Many went through Andrew and the news down there goes nuts with hurricanes getting everyone all frenzied.  Source:  mom, dad, brother, uncles, aunts, cousins all in ft lauderdale.

 

Also, one factor with supplies is that it's likely for some chains that the stock remaining in Florida stores is less than usual because of inventory and distribution center restock allocations being diverted to Harvey stores.  Basically it's a bet that you won't have a run on those SKUs in the sending/low-restock locations while you're diverting inventory and restocks to other places that ARE having a run on those SKUs.  Ideally there would be a long enough interval between runs-on-SKUs that your supply chain has time to catch up and top off the shorted stores.

The algorithms involved are pretty neat.  They were this really cool blend of shipping logistics, inventory tracking-projection-restock, direct-ship vs ship-forward, and "Make it so" hand-waving.

 

 

[Chinook]

I don't know if this was posted yet. Irma Recon Flight#5 (earlier today, before flight #6) had a minimum SLP of 945mb (fairly steady, considering other SLP values today). Other relevant data shows 133 kts at flight level, and 112 kts at the surface.

Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 5th day of the month at 2:12Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
B. Center Fix Coordinates: 16°40'N 55°30'W (16.6667N 55.5W)
D. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 112kts (~ 128.9mph)
E. Location of the Estimated Maximum Surface Wind Inbound: 12 nautical miles (14 statute miles) to the ESE (116°) of center fix
F. Maximum Flight Level Wind Inbound: From 211° at 117kts (From the SSW at ~ 134.6mph)

H. Minimum Sea Level Pressure: 945mb (27.91 inHg)
Remarks Section:
Maximum Flight Level Outbound and Flight Level Wind: 133kts (~ 153.1mph) which was observed 18 nautical miles (21 statute miles) to the NW (313°) from the flight level center at 1:54:01Z