CPAC: ISELLE - Post-Tropical

[Yellow Evan]

What is causing the storm to weaken? SSTs are more than adequate, shear appears light. How is the thermodynamic environment different from a westward-marching Cape Verde system?

Shear have been slowly increasing since this morning, probably around 15-20kt right now

SHIPS anaylized at 18knts, which ins't too bad but enough to cause further weakening.

[supercane4867]

Dropsonde data may still supports 65kt hurricane intensity

Level Wind Direction Wind Speed
996mb (Surface) 105° (from the ESE) 64 knots (74 mph)
993mb 105° (from the ESE) 63 knots (72 mph)
987mb 115° (from the ESE) 74 knots (85 mph)
973mb 120° (from the ESE) 80 knots (92 mph)
931mb 130° (from the SE) 73 knots (84 mph)
924mb 125° (from the SE) 77 knots (89 mph)
917mb 125° (from the SE) 73 knots (84 mph)
875mb 125° (from the SE) 81 knots (93 mph)
850mb 130° (from the SE) 79 knots (91 mph)
697mb 145° (from the SE) 49 knots (56 mph)

Mean Boundary Level Wind: 75 knots (86 mph)

[Yellow Evan]

What is the latest from Recon?

Borderline Hurricane/Tropical Sorm. New blowup of convection though. They'll probably keep it as cane' just incase.

SAB is at 77 knts, and they like to factor in satellite intensity estimates. I say it'll be 65-70 knts.

Presentation looks like 50-55 knts though. On a second thought, I'd say they go 60-65 knts.

[WeatherGuesser]

How long to landfall? 8-10 hours?

[Kingarabian]

How long to landfall? 8-10 hours?

Around 8.

[supercane4867]

Presentation looks like 50-55 knts though. On a second thought, I'd say they go 60-65 knts.

Well if Bertha could be a hurricane, why this one can‘t

[tallywx]

Dropsonde data may still supports 65kt hurricane intensity

Level Wind Direction Wind Speed
996mb (Surface) 105° (from the ESE) 64 knots (74 mph)
993mb 105° (from the ESE) 63 knots (72 mph)
987mb 115° (from the ESE) 74 knots (85 mph)
973mb 120° (from the ESE) 80 knots (92 mph)
931mb 130° (from the SE) 73 knots (84 mph)
924mb 125° (from the SE) 77 knots (89 mph)
917mb 125° (from the SE) 73 knots (84 mph)
875mb 125° (from the SE) 81 knots (93 mph)
850mb 130° (from the SE) 79 knots (91 mph)
697mb 145° (from the SE) 49 knots (56 mph)

Mean Boundary Level Wind: 75 knots (86 mph)

Those are still very strong winds just off the surface. 973mb off of 996mb surface is only about 500 feet up. 875 mb is 4500 feet up. So even at strong TS/minimal hurricane strength, a lot of towns could still get 85-95 mph winds. Wow.

If I were Jim Cantore, I'd be reporting from Pahoa or higher up the hill as opposed to at the shoreline where one tends to go for these things.

[Yellow Evan]

Dropsonde data may still supports 65kt hurricane intensity

Level Wind Direction Wind Speed
996mb (Surface) 105° (from the ESE) 64 knots (74 mph)
993mb 105° (from the ESE) 63 knots (72 mph)
987mb 115° (from the ESE) 74 knots (85 mph)
973mb 120° (from the ESE) 80 knots (92 mph)
931mb 130° (from the SE) 73 knots (84 mph)
924mb 125° (from the SE) 77 knots (89 mph)
917mb 125° (from the SE) 73 knots (84 mph)
875mb 125° (from the SE) 81 knots (93 mph)
850mb 130° (from the SE) 79 knots (91 mph)
697mb 145° (from the SE) 49 knots (56 mph)

Mean Boundary Level Wind: 75 knots (86 mph)

Those are still very strong winds just off the surface. 973mb off of 996mb surface is only about 500 feet up. 875 mb is 4500 feet up. So even at strong TS/minimal hurricane strength, a lot of towns could still get 85-95 mph winds. Wow.

If I were Jim Cantore, I'd be reporting from Pahoa or higher up the hill as opposed to at the shoreline where one tends to go for these things.

Not to mention winds could be even higher on the leeward/Kona side.

[Janie2006]

I get the impression that some people, if they aren't paying attention, are going to get a nasty surprise rather shortly....especially on the mountainsides. Assume that the 850 mb readings are correct, and that's 5000 ft at MSL, then consider the terrain on the Big Island. I can see why they remain rather bullish on Iselle.

[Kingarabian]

I get the impression that some people, if they aren't paying attention, are going to get a nasty surprise rather shortly....especially on the mountainsides.

Yep. I heard some people were going to try and surf on the big Island.

[Yellow Evan]

Advisory should be out soon. Here we go.

[micktooth]

How long to landfall? 8-10 hours?

Around 8.

Eye or CoC now visible on radar http://radar.weather.gov/radar.php?rid=HWA&product=N0Z&overlay=11101111&loop=yes

[Yellow Evan]

Hurricane ISELLE Advisory Number 31
Issued at 1100 AM HST THU AUG 07 2014
SUMMARY OF 1100 AM HST...2100 UTC...INFORMATION
-----------------------------------------------
Location: 18.9N 152.2W
ABOUT 195 MI...315 KM ESE OF HILO HAWAII
ABOUT 405 MI...650 KM ESE OF HONOLULU HAWAII
Maximum sustained winds: 75 MPH...120 KM/H
Present movement: WNW or 285 degrees AT 16 MPH...26 KM/H
Minimum central pressure: 991 MB...29.27 INCHES

WATCHES AND WARNINGS
--------------------
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

NONE.

[Janie2006]

Still holding on as a Cat 1. Meanwhile, the first bands are approaching the island.

[WeatherGuesser]

Eye or CoC now visible on radar

GR3 using the South Shore station shows a rain band reaching the eastern point.

[Yellow Evan]

Eye or CoC now visible on radar

GR3 using the South Shore station shows a rain band reaching the eastern point.

How long would you say are we from landfall? CPHC thinks 12 hours.

[Alyono]

cphc is saying about 9 hours. The forecast is not a 12 hour forecast as it started at 18Z, not 21Z

[TheStormExpert]

Looks like it won't be a hurricane at landfall after all according to latest advisory.

[Yellow Evan]

Looks like it won't be a hurricane at landfall after all according to latest advisory.

It could if convection increases a little

[Kingarabian]

Looks like it won't be a hurricane at landfall after all according to latest advisory.

It could if convection increases a little

Interestingly, last few frames show that.