Major Hurricane Irma

[NJwx85]

The 12z HWRF has Irma down to 920 at 18z, so fairly accurate.

Hovers Irma in the 910's/920's over the next 60hrs.

[beanskip]

12z HWRF bit faster and stronger vs. 6z.

[bobbutts]

12 minutes ago, Hoosier said:

Nobody should be dismissing anything at this point, except maybe landfall in Texas or Bermuda.

Really can't stress enough to our guests and newer members that a wide range of options is still on the table.  Models will move around with each run.   

Anything outside the 3 day NHC cone is going to be very speculative.  The error on the 5 day cone is so large that it could be south of Cuba or missing the FL E. Coast.  We can take a hint from the lack of confidence from the best in the biz.

 

[Casualbrain]

3 minutes ago, NWLinnCountyIA said:

It's approaching it's hypothesized MPI for the current SST, although the water continues to warm as it moves west, but this should provide at least a nubulous upper bound for intensity.

It's pretty darn close to MPI per charts

 

[bobbutts]

4 minutes ago, Eskimo Joe said:

How are you able to make a .gif off that site?

Screen cap with OBS Studio.. Edit clip in your favorite video editor.  Giphy (website) to convert to .gif.

[OSUmetstud]

10 minutes ago, Eskimo Joe said:

Folks, stop looking at the CMC.  It's not trustworthy for TCs.

On that basis neither is the gfs.  Theyve had similar error re: irma. 

[Paleocene]

Another site worth booking - COD's GOES16 site. 

Fixed floater on Irma available with many options. Including 200 frame animations.

http://weather.cod.edu/satrad/exper/?parms=meso1-02-200-0

[beanskip]

HWRF through 66 hours, a bit south of 6z position and a little faster.

[jojo762]

Definitely more of a northerly component to the movement of Irma per latest center dropsonde.

[Drz1111]

4 minutes ago, Casualbrain said:

It's pretty darn close to MPI per charts

 

 

Historically, quasi-annular long track CV hurricanes get about as close as you can to the theoretical slope of MPI.  Georges did that BitD, also had annular characteristics and was a long tracker in a similar spot.

[packfan98]

12z GEFS mean has a LF in Cuba and is further south and west than 6z.

[NJwx85]

I thought this was pretty LOL worthy. It's obviously really far off intensity wise, however it does show Irma staying away from Cuba and deepening rapidly as it approaches FL.

[NJwx85]

The UKMET still has Irma crossing Cuba, however it quickly re-deepens on approach to FL

 

[Hoosier]

5 minutes ago, packfan98 said:

12z GEFS mean has a LF in Cuba and is further south and west than 6z.

A number of individual members in Cuba

[Baroclinic Zone]

Just now, Hoosier said:

A number of individual members in Cuba

Right up into MIA on the mean too.  

[NJwx85]

The 12z HWRF has landfall in Cuba

[Heisy]

Hypothetically if Irma were to head into Cuba but then turn and steer into MIA, would she have enough time to redevelop into a 4-5? 

[Windspeed]

Irma's intensification the past 12 hours is a good example of why the lowest central pressure observed is not a perfect sliding scale indicative of maximum sustained wind. Some hurricanes may form and intensify within a large surface trough with lower background pressure or not have interaction with a high millibar pressure surface ridge such as Irma. Even considering Irma's large eyewall and increasing wind field, it is within the southern periphery of high background surface pressure with a very intense pressure gradient. This is similar to other intense hurricanes in this region (Isabel being a great example).

 

As Irma continues WNW near or just north of the Greater Antilles and as it begins to position itself on the SW periphery of the ridge, background pressures will decrease. Additionally, Irma may continue to expand in size. As such, the pressure gradient will decrease around the vortex. It may very well end up having sub 920 mb pressures but weaker overall sustained winds. I am not saying this won't be a Cat 5 at some point in the Bahamas or north of the Antilles, I just think the overall sustained surface winds of 180 mph won't be observed in the Bahamas or near the SE CONUS. The size of the cyclone, lower background pressures/pressure gradient being the key factors here.

 

Obviously this post is semantics over peak intensity and is not in anyway deflection of how incredibly dangerous this hurricane will be in both winds and surge to what ever islands/landmass it will eventually encounter.

[Hoosier]

2 minutes ago, Wentzadelphia said:

Hypothetically if Irma were to head into Cuba but then turn and steer into MIA, would she have enough time to redevelop into a 4-5? 

Yes, but it would depend on how much time is spent in Cuba.  Other than land interaction, there is not much on the broader scale to suggest weakening in that area.

[yoda]

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 5th day of the month at 17:05Z
Agency: United States Air Force 
Aircraft: Lockheed WC-130J Hercules with reg. number AF99-5309 
Storm Number & Year: 11 in 2017
Storm Name: Irma (flight in the North Atlantic basin)
Mission Number: 8
Observation Number: 21 ( See all messages of this type for this mission. )
A. Time of Center Fix: 5th day of the month at 16:38:10Z
B. Center Fix Coordinates: 16°53'N 58°53'W (16.8833N 58.8833W)
B. Center Fix Location: 197 statute miles (317 km) to the E (95°) from Saint John's, Antigua and Barbuda.
C. Minimum Height at Standard Level: 2,440m (8,005ft) at 700mb
D. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 160kts (~ 184.1mph)
E. Location of the Estimated Maximum Surface Wind Inbound: 14 nautical miles (16 statute miles) to the NE (54°) of center fix
F. Maximum Flight Level Wind Inbound: From 138° at 151kts (From the SE at ~ 173.8mph)
G. Location of Maximum Flight Level Wind Inbound: 15 nautical miles (17 statute miles) to the NE (54°) of center fix
H. Minimum Sea Level Pressure: 926mb (27.35 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 9°C (48°F) at a pressure alt. of 3,066m (10,059ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 18°C (64°F) at a pressure alt. of 3,052m (10,013ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 13°C (55°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Closed 
M. Eye Shape & Diameter: Circular with a diameter of 24 nautical miles (28 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 700mb
O. Navigational Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile

Remarks Section:
Maximum Flight Level Wind: 151kts (~ 173.8mph) which was observed 15 nautical miles (17 statute miles) to the NE (54°) from the flight level center at 16:33:00Z
Maximum Flight Level Wind Outbound: 148kts (~ 170.3mph) which was observed 16 nautical miles (18 statute miles) to the WNW (299°) from the flight level center at 16:44:30Z
Dropsonde Surface Wind at Center: From 180° at 4kts (From the S at 5mph)
Maximum Flight Level Temp: 19°C (66°F) which was observed 7 nautical miles to the ENE (62°) from the flight level center

[donsutherland1]

3 minutes ago, Wentzadelphia said:

Hypothetically if Irma were to head into Cuba but then turn and steer into MIA, would she have enough time to redevelop into a 4-5? 

Location of landfall and duration of time over Cuba would be key. Below is a link to Cuba's topography:

http://en-us.topographic-map.com/places/Cuba-7906713/

[NJwx85]

Really bad for FLL and especially PBI

[Drz1111]

5 minutes ago, NJwx85 said:

Really bad for FLL and especially PBI

with the HMON's mean track error this summer, I'm not sure if Halifax shouldn't be watching closely.

[Eskimo Joe]

Quote

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 5th day of the month at 17:05Z
Agency: United States Air Force 
Aircraft: Lockheed WC-130J Hercules with reg. number AF99-5309 
Storm Number & Year: 11 in 2017
Storm Name: Irma (flight in the North Atlantic basin)
Mission Number: 8
Observation Number: 21 ( See all messages of this type for this mission. )
A. Time of Center Fix: 5th day of the month at 16:38:10Z
B. Center Fix Coordinates: 16°53'N 58°53'W (16.8833N 58.8833W)
B. Center Fix Location: 197 statute miles (317 km) to the E (95°) from Saint John's, Antigua and Barbuda.
C. Minimum Height at Standard Level: 2,440m (8,005ft) at 700mb
D. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 160kts (~ 184.1mph)
E. Location of the Estimated Maximum Surface Wind Inbound: 14 nautical miles (16 statute miles) to the NE (54°) of center fix
F. Maximum Flight Level Wind Inbound: From 138° at 151kts (From the SE at ~ 173.8mph)
G. Location of Maximum Flight Level Wind Inbound: 15 nautical miles (17 statute miles) to the NE (54°) of center fix
H. Minimum Sea Level Pressure: 926mb (27.35 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 9°C (48°F) at a pressure alt. of 3,066m (10,059ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 18°C (64°F) at a pressure alt. of 3,052m (10,013ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 13°C (55°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Closed 
M. Eye Shape & Diameter: Circular with a diameter of 24 nautical miles (28 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 700mb
O. Navigational Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile

Remarks Section:
Maximum Flight Level Wind: 151kts (~ 173.8mph) which was observed 15 nautical miles (17 statute miles) to the NE (54°) from the flight level center at 16:33:00Z
Maximum Flight Level Wind Outbound: 148kts (~ 170.3mph) which was observed 16 nautical miles (18 statute miles) to the WNW (299°) from the flight level center at 16:44:30Z
Dropsonde Surface Wind at Center: From 180° at 4kts (From the S at 5mph)
Maximum Flight Level Temp: 19°C (66°F) which was observed 7 nautical miles to the ENE (62°) from the flight level center

 

[SnowGoose69]

I'll go out on a limb and say this airport forecast for St. Marteen looks underdone.  

TNCM 051720Z 0518/0618 04014KT P6SM VCSH SCT018 
  FM052300 35025G35KT 4SM TSRA BKN018CB OVC040 
  FM061300 03016G28KT P6SM VCTS SCT018CB SCT030 
  FM061700 04018G35KT P6SM -TSRA SCT018CB BKN035

[jbenedet]

5 minutes ago, NJwx85 said:

Really bad for FLL and especially PBI

Big shift east versus 6z. 6z had her going into the gulf before recurvig into the south west coast of Fla.

[donsutherland1]

2 minutes ago, Deaglesnest said:

What are the chances this thing actually gets into the gulf now. Thank you for the link to the topography of Cuba btw, good stuff. 

Probably a 20%-30% chance if one goes by the 0z ECMWF ensembles; less than that if one goes by the 12z GEFS. The ECWMF will be initializing momentarily so we'll get more information in a little while.

[NJwx85]

The next aircraft just departed base, should be there for the 5PM advisory.

[Buddy1987]

8 minutes ago, donsutherland1 said:

Location of landfall and duration of time over Cuba would be key. Below is a link to Cuba's topography:

http://en-us.topographic-map.com/places/Cuba-7906713/

Don, that is extremely helpful info for some of the questions people may have with disruption of the center if Irma were to have Cuba affect her. I could only find mountain ranges in the 500-700 foot range along the north central coasts, so I am not particularly sure how much it would definitely affect her, however toward Guantanamo you are looking at some ranges of 1700 ft or more potentially. Not sure many models have the track that far south however. Ultimately, as people have mentioned, makes a difference how long the eyewall were to spend over Cuba.

[donsutherland1]

NHC's 2 pm update: Irma's maximum sustained winds increased further to 185 mph. This ties Irma for the second strongest Atlantic basin hurricane in terms of maximum sustained winds.