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Rare Twin Hurricanes Headed Towards Hawaii

By: Dr. Jeff Masters, 5:05 PM GMT on August 06, 2014

Rare twin Category 1 hurricanes are nearing Hawaii as Hurricane Iselle, with 85 mph winds, and Hurricane Julio, with 75 mph winds, steam west-northwest towards the islands. Both hurricanes are expected to weaken to tropical storms before they affect Hawaii. Iselle is the bigger danger, as it is expected to make a direct hit on Thursday evening, while Julio's center is expected to pass about 100 miles to the northeast of the islands on Sunday. Satellite images show that Iselle has weakened significantly over the past day. Though the hurricane still has a prominent eye, the eyewall's heavy thunderstorms are much reduced in intensity and areal coverage, due to wind shear and dry air. A new Air Force hurricane hunter aircraft is scheduled to be in the storm near 1 pm EDT Wednesday, and the NOAA jet will fly another dropsonde mission Wednesday evening. The outer spiral bands of Iselle were not yet visible on Hawaii radar on Wednesday morning, but should come into view late Wednesday night.


Figure 1. Official forecast and uncertainty cones for Hurricane Iselle and Hurricane Julio, made at 11 am EDT Wednesday August 6, 2014. Image taken from our wundermap with the Tropical layer turned on.

Forecast for Iselle
Wind shear is expected to stay moderate until Iselle reaches the islands Thursday evening. Ocean temperatures will remain a marginal 26°C, and the atmosphere surrounding the storm will steadily dry, resulting in continued weakening of Iselle. Just how weak the storm will be when it arrives in the islands Thursday afternoon and evening is a matter of considerable disagreement amount our top intensity models; the Wednesday morning runs of the LGEM, GFDL, and HWRF models predicted a strong tropical storm or weak Category 1 hurricane with 65 - 75 mph winds at 8 pm EDT Thursday, while the DSHIPS model predicted a much weaker system with 45 - 50 mph winds. Historically, only one tropical storm and no hurricanes approaching from the east have ever hit the islands, and this climatology would argue for a weaker Iselle on Thursday evening. The official CPHC forecast for a 60 - 65 mph tropical storm is reasonable, but Iselle could easily be a 50 - 55 mph storm Thursday evening. Regardless, the main threat from Iselle will be heavy rains leading to flash flooding and mudslides, and the storm will be capable of generating dangerous heavy rains when it reaches the islands. The Wednesday morning 12Z run of the GFDL model predicted that Iselle would dump widespread rains of 4 - 8" over the islands, with some regions seeing 8 - 16". Wind damage is also a concern from Iselle; the 5 pm EDT Wednesday Wind Probability Forecast from Central Pacific Hurricane Center (CPHC) gave Hilo on the Big Island a 72% chance of experiencing tropical storm-force winds of 39+ mph, and a 8% chance of hurricane-force winds. These odds were 30% and 2%, respectively, for Honolulu. High surf of 10 - 20' and higher will also pound the islands, causing erosion problems and coastal flooding.


Figure 2. Predicted rainfall along the track of Hurricane Iselle from the 12Z (8 am EDT) Wednesday August 6, 2014 run of the GFDL model. The model forecasts that Iselle will be a strong tropical storm with 60 - 65 mph winds when it hits the islands Thursday evening. Widespread rains of 4 - 8" are predicted over the islands, with some regions seeing 8 - 16". Image credit: NOAA/GFDL.

Julio becomes a hurricane
Hawaii's other hurricane threat is Hurricane Julio, which intensified to a Category 1 hurricane with 75 mph winds at 5 am EDT on Wednesday. Julio's ascension to hurricane status now gives the Eastern Pacific 10 named storms, 5 hurricanes, and 3 intense hurricanes so far in 2014. On average, we expect to see just 6 named storms, 3 hurricanes, and 1 intense hurricane by August 6. Satellite loops show that Julio is not very impressive yet, with only a modest area of heavy thunderstorms and no eye. The storm should be able to take advantage of light to moderate wind shear and marginally warm sea surface temperatures near 26°C to intensify 5 - 15 mph by Thursday. Higher wind shear and drier air should induce weakening beginning on Friday. The models have been increasingly enthusiastic about Julio taking a bend to the right in its track this weekend, putting the center of the storm about 100 miles northeast of the Hawaiian Islands on Sunday. On this path, Julio's core of heavy rains of 8 - 16" would miss the islands, and high surf would be the main impact of the storm. The edge of Julio's cone of uncertainly for Sunday still lies over the islands, so we cannot yet be confident of this track, but I am cautiously optimistic that Hawaii will avoid torrential rains from Julio falling upon soils already saturated by Iselle.


Figure 3. Tracks of all tropical cyclones (tropical depressions, tropical storms, and hurricanes) to pass within 100 miles of the Hawaiian Islands, 1949 - 2013. Hurricanes approaching from the east typically fall apart before they reach Hawaii due to the cool waters and dry air that lie to the east of the islands. Only one named storm approaching from the east has hit the islands since 1949, an unnamed 1958 tropical storm that hit the Big Island. Hurricanes approaching from the south represent the biggest danger to the islands, due to the warmer waters and more unstable air present to the south. The only two major hurricanes to have affected the islands since 1949, Hurricane Iniki of 1992 and Hurricane Dot of 1959, both came from the south. Image credit: NOAA/CSC.

Hawaii's hurricane history
On average, between four and five tropical cyclones are observed in the Central Pacific every year. This number has ranged from zero, most recently as 1979, to as many as eleven in 1992 and 1994. August is the peak month, followed by July, then September. Tropical storms and hurricanes are rare in the Hawaiian Islands. Since 1949, the Hawaiian Islands have received a direct hit from just two hurricanes--Dot in 1959, and Iniki in 1992. Both hit the island of Kauai. Only one tropical storm has hit the islands since 1949--an unnamed 1958 storm that hit the Big Island. A brief summary of the three most significant hurricanes to affect Hawaii in modern times:

September 1992: Hurricane Iniki was the strongest, deadliest, and most damaging hurricane to affect Hawaii since records began. It hit the island of Kauai as a Category 4 on September 11, killing six and causing $2 billion in damage.

November 1982: Hurricane Iwa was one of Hawaii's most damaging hurricanes. Although it was only a Category 1 storm, it passed just miles west of Kauai, moving at a speed of nearly 50 miles per hour (80 km/h). Iwa killed one person and did $250 million in damage, making it the second most damaging hurricane to ever hit Hawaii. All the islands reported some surf damage along their southwest facing shores, and wind damage was widespread on Kauai.

August 1959: Hurricane Dot entered the Central Pacific as a Category 4 hurricane just south of Hawaii, but weakened to a Category 1 storm before making landfall on Kauai. Dot brought sustained winds of 81 mph with gusts to 103 mph to Kilauea Light. Damage was in excess of $6 million. No Dot-related deaths were recorded.


Figure 4. Typhoon Halong as photographed and tweeted by astronaut Reid Wiseman at 09 UTC August 6, 2014. At the time, Halong was a Category 2 storm with 100 mph winds.

Typhoon Halong headed towards Japan
In the Western Pacific, Typhoon Halong was a Category 2 storm with 100 mph winds at 8 am EDT Wednesday. Satellite loops show that Halong has intensified since Tuesday, with concentric eyewalls and a prominent eye now visible. Halong is expected to affect Southern Japan as a Category 1 typhoon late this week.

Bertha declared extratropical
In the Atlantic, Tropical Storm Bertha has lost its tropical characteristics over the cold waters south of Canada, and NHC has issued its last advisory on the storm. There are no threat areas to discuss in the Atlantic, and none of the reliable models for predicting tropical cyclone genesis forecasts anything to develop in the next five days.


Video 1. The Discovery Channel's "Destroyed in Seconds" chronicles the devastating impact of 1992's Category 4 Hurricane Iniki on Kauai, Hawaii. Iniki was the strongest hurricane ever recorded to hit the Hawaiian Islands.

Jeff Masters

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Quoting 499. ScottLincoln:


I wonder by how much this differs from climatology?


I never pay attention to those graphics issued by Accuweather. Honestly, i always feel like their strategy is "if we make it far enough in advance, then YaY if we're right, and if its wrong no one will remember."

Edit: Also, I agree with ScottLincoln. . . they never differ much from climatology, so even when they're off, they're "close"
Hot and steamy morning across S.W. Florida with dewpoints in the mid to upper 70s creating a high heat index for most locations.

Genevieve flew through her Annular screening as well as the date line.. she's the first storm to go from the East Pacific, all the way to the West Pacific since Jimena in 2003

## ANNULAR HURRICANE INDEX (AHI) EP072014 GENEVIEVE 08/07/14 00 UTC ##
## PASSED SCREENING STEP, MIGHT BE ANNULAR, CALCULATE AHI FROM DISCRIMINANT ANALYSIS ##
## AHI=100 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

The GFS is vary stormy for this time of year in the W PAC. The storm are even getting stronger I see a vary early start two CA rainy season


Good Morning.  In furtherance of the current difference between the Atlantic and Pacific Basins, and what has been characterized as El Nino conditions in the Pacific (although not officially declared yet)  here is a blurb from the 2013 Atlantic post-season recap by Klotzbach and Gray: 

Reasons for the 2013 hurricane season being so weak? The majority of Atlantic basin 
hurricane seasons with the least amount of activity occur in El Nino years. The average 
amount of hurricane activity as expressed by ACE in 12 (or 20%) of the last 64 years in 
which moderate or strong El Ninos have occurred was only 50. The average ACE of the 
other 48 (or 80% of years since 1950) years in which El Nino activity was not present 
was 120 or 240 percent greater. The 2013 Atlantic hurricane season had an ACE value 
of only 33. This low hurricane season is only rivaled for low activity since 1950 during 
non-El Nino years by 1962 (ACE = 36), 1968 (ACE = 45), 1977 (ACE = 25), 1993 (ACE = 39), 
and 1994 (ACE = 32). 

We attribute a sizable portion of the reduction in the 2013 hurricane activity to the 
unusual springtime (April through June) weakening of the THC/AMO and the associated 
large increase in strength of the Atlantic gyre. We failed to realize the importance of this 
first half of the year reduction in the strength of the THC and increase in strength of the 
subtropical gyre. Part of our failure was due to the rapid reversal in strength of the THC 
(and gyre) in July that has continued to the present. We will use this 2013 experience to 
more carefully monitor the smaller-scale changes of the THC in the future. 

The answer to these questions for this season and what happens on the Atlantic side will be answered within the next 60 days. I am sure that some on here will post the current Atlantic ACE values, and THC/AMO stats for comparison to last year at this time.  




Quoting 458. islander101010:

hiked mauna loa back in the 80s on a a rugged trail to the caldera. there is a small cabin up there. when we climbed it there was fresh snow at least a ft deep picture is in my photos section

I visited Hawaii and went to the Big Island in 2007 (ironically arriving as Hurricane Flossie was a Cat 4. heading toward Hawaii and stubbornly refusing to weaken) We didn't hike Mauna Loa, but it was August and there wasn't snow on the top. We hiked to the Halumaumau crater, Kilauea Iki crater, and an evening hike through old lava fields to try to see the current active lava flow to the sea. The Big Island with the volcanoes was equally exciting as Oahu for me.

Really hard to believe a Cat 1. hurricane could hit there from the East. It actually would be fascinating to see Iselle maintain Cat. 1 intensity till landfall and observe what kind of effects it brings.
Quoting 454. MAweatherboy1:

80kt increase in 24 hours per the JTWC. That's almost unheard of.




Hurricane Felix increased by 85kts in 24 hours. Hurricane Wilma did the same too I think. I'm sure there are plenty of other examples of WPAC systems. It's certainly amazing to see though!
Plowing it's way through. Looks like dry air isn't as much of an issue as it was earlier.
510. MAstu
think Genevieve can make it into the Indian ocean? Sure, she's curving out now, but she's made it this far...
One facet of AGW is addressed in this NYT article:overpopulation Link
512. MahFL
Quoting 491. StormTrackerScott:


The ENSO Precipitation Index (ESPI) for the last 30 days is 0.82


What does that mean ?
Quoting 499. ScottLincoln:


I wonder by how much this differs from climatology?


With El-Nino you tend to get a stronger southern jet leading to greater chances of severe weather activity during the cooler months. Remember November 2002?

The 2002 Veterans Day Weekend tornado outbreak was a large, widespread and rare outbreak of storms that occurred from the late afternoon hours on November 9 through the early morning hours on Veterans Day, November 11, 2002. Eighty-three tornadoes hit 17 states. Twelve tornadoes killed 36 people in five states. This ranks as the second biggest outbreak ever recorded in November.

Quoting Envoirment:


Hurricane Felix increased by 85kts in 24 hours. Hurricane Wilma did the same too I think. I'm sure there are plenty of other examples of WPAC systems. It's certainly amazing to see though!


Wilma intensified 170 km/h in 24 hours (90 knots).

During October 2005, Hurricane Wilma sustained winds rapidly intensified, from 60 knots (70 mph;110 km/h to 150 knots (175 mph; 280 km/h within 24 hours.[8] As a result Wilma intensified from being a tropical storm to a category 5 hurricane on the Saffir-Simpson hurricane scale.[8] Over the same time span the pressure dropped from 982 hectopascals (29.00 inHg) to 892 hectopascals (26.34 inHg).[8]
Wiki
Japan Meteorological Agency
Tropical Cyclone Advisory #3
Typhoon Warning
TYPHOON GENEVIEVE (1413)
21:00 PM JST August 7 2014
==============================

SUBJECT: GENEVIEVE Near Midway Islands

At 12:00 PM UTC, Typhoon Genevieve (950 hPa) located at 15.1N 178.7E has 10 minute sustained winds of 100 knots with gusts of 140 knots. The cyclone is reported as moving west northwest at 14 knots.

Storm Force Winds
================
50 NM from the center

Gale Force Winds
============
120 NM from the center

Dvorak Intensity: T6.5

Forecast and Intensity
==================
24 HRS: 18.4N 175.4E- 105 knots (CAT 5/Intense Typhoon) Midway Islands waters
48 HRS: 22.6N 174.6E - 100 knots (CAT 4/Very Strong Typhoon) Wake Island waters
72 HRS: 28.8N 171.1E - 90 knots (CAT 4/Very Strong Typhoon) Wake Island waters

Japan Meteorological Agency
Tropical Cyclone Advisory #77
Typhoon Warning
TYPHOON HALONG (1411)
21:00 PM JST August 7 2014
==============================

SUBJECT: HALONG 80 KM Northeast Of Minami Daito Island

At 12:00 PM UTC, Typhoon Halong (945 hPa) located at 26.3N 131.7E has 10 minute sustained winds of 75 knots with gusts of 105 knots. The cyclone is reported as moving north at 7 knots.

Storm Force Winds
================
110 NM from the center in southeast quadrant
80 NM from the center in northwest quadrant

Gale Force Winds
============
300 NM from the center in east quadrant
180 NM from the center in west quadrant

Dvorak Intensity: T4.5

Forecast and Intensity
==================
24 HRS: 28.8N 131.7E - 75 knots (CAT 3/Strong Typhoon) southeast of Yakushima [Kagoshima Prefecture]
48 HRS: 33.1N 132.8E - 75 knots (CAT 3/Strong Typhoon) Overland Shikoku [Kōchi Prefecture]
72 HRS: 39.3N 135.6E - 60 knots (CAT 2/Severe Tropical Storm) Sea of ​​Japan
Quoting 512. MahFL:



What does that mean ?


It means the atmosphere is set for El-Nino to occur as more and more convection focuses across the central & eastern equatorial Pacific as opposed to the W-Pac. With El-Nino you get a reverse in the trade winds which focuses convection on our side of the Pacific.
The last Aussie Met Office ENSO update was issued on July 29th with this general heading:
 

El Niño indicators ease

Issued on Tuesday 29 July 2014 | 

Despite the tropical Pacific Ocean being primed for an El Niño during much of the first half of 2014, the atmosphere above has largely failed to respond, and hence the ocean and atmosphere have not reinforced each other. As a result, some cooling has now taken place in the central and eastern tropical Pacific Ocean, with most of the key NINO regions returning to neutral values.

While the chance of an El Niño in 2014 has clearly eased, warmer-than-average waters persist in parts of the tropical Pacific, and the (slight) majority of climate models suggest El Niño remains likely for spring. Hence the establishment of El Niño before year's end cannot be ruled out. If an El Niño were to occur, it is increasingly unlikely to be a strong event.

Their next update comes out next Tuesday morning on August 12th.

Quoting 518. Tazmanian:




Yawn. Old news


They can say that if they want but you don't have to look far to see that this second subsurface warm pool is coming at a good time as the atmosphere has transitioned toward El-Nino which wasn't the case during the warm pool this past spring.
The CPC has decreased their odds of El Nino down to 65%.

Link
521. MahFL
Quoting 518. Tazmanian:
Yawn. Old news

It is the official current state though.
Eric Blake from NHC tweeted last night that Julio is going to pass through an environment very similar to the one that enabled Iselle to go annular, so it'll be interesting to see if it consolidates its structure any further.

Quoting 512. MahFL:



What does that mean ?

Most likely we will see some El Nino conditions in the next few weeks, where region 3,4 warms to greater than 0.5.

It's far from an indicator that an offical El Nino will be declared. That takes alot of persistent El Nino conditions..far beyond the time scope ESPI can predict..
Quoting 520. TropicalAnalystwx13:

The CPC has decreased their odds of El Nino down to 65%.

Link


deja vu? (2012)
Quoting 522. TimSoCal:

Eric Blake from NHC tweeted last night that Julio is going to pass through an environment very similar to the one that enabled Iselle to go annular, so it'll be interesting to see if it consolidates its structure any further.




There is evident structure changes in the last half of the loop. Julio could be making its way to becoming annular soon.
Quoting 523. Skyepony:


Most likely we will see some El Nino conditions in the next few weeks, where region 3,4 warms to greater than 0.5.

It's far from an indicator that an offical El Nino will be declared. That takes alot of persistent El Nino conditions..far beyond the time scope ESPI can predict..


Wouldn't region 3.4 indicate a Modoki El Nino? Seems like that would explain why the central Pacific has been as conducive as it's been.
Quoting 522. TimSoCal:

Eric Blake from NHC tweeted last night that Julio is going to pass through an environment very similar to the one that enabled Iselle to go annular, so it'll be interesting to see if it consolidates its structure any further.




Genevieve is raging annular right now...

Here is Julio's screening from this morning..


## ANNULAR HURRICANE INDEX (AHI) EP102014 JULIO 08/07/14 00 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
Quoting 522. TimSoCal:

Eric Blake from NHC tweeted last night that Julio is going to pass through an environment very similar to the one that enabled Iselle to go annular, so it'll be interesting to see if it consolidates its structure any further.



Still looks to be improving it's structure in that specific imagery loop. Has it been tracking north or south of guidance so far to date? Seems like it hasn't deviated to far from it's forecasted track.
The fact about this El Nino is that we're nowhere close to an El Nino. The atmosphere isn't responding and even the equatorial East Pacific anomalies have been unstable. The subsurface warm pool has faded away to nothing in the absence of sustained westerly winds, and subsequent ones will do so the same until we get those winds. The issue is that sea surface temperatures along the entire equatorial Pacific (East, Central, West) are fairly uniform, meaning you're not getting that wind gradient you want to sustain westerly winds. Compare the average vs. what we're observing:


Quoting 527. Stoopid1:



Wouldn't region 3.4 indicate a Modoki El Nino? Seems like that would explain why the central Pacific has been as conducive as it's been.


No, that's the region that is looked at to declare ENSO conditions, regardless of the type.

EPAC has been super active. Those storms are moving into the CPAC area making it more active. Overall the conditions are better in the Pacific for storms right now.
Quoting 519. StormTrackerScott:



They can say that if they want but you don't have to look far to see that this second subsurface warm pool is coming at a good time as the atmosphere has transitioned toward El-Nino which wasn't the case during the warm pool this past spring.
This will be an interesting Nino to watch regardless of strength. Strange weather makes it more interesting.... to me...:)....
Quoting 506. opal92nwf:


I visited Hawaii and went to the Big Island in 2007 (ironically arriving as Hurricane Flossie was a Cat 4. heading toward Hawaii and stubbornly refusing to weaken) We didn't hike Mauna Loa, but it was August and there wasn't snow on the top. We hiked to the Halumaumau crater, Kilauea Iki crater, and an evening hike through old lava fields to try to see the current active lava flow to the sea. The Big Island with the volcanoes was equally exciting as Oahu for me.

Really hard to believe a Cat 1. hurricane could hit there from the East. It actually would be fascinating to see Iselle maintain Cat. 1 intensity till landfall and observe what kind of effects it brings.


Wonder what this system would have been like without the intense dry air environment the last few days. We've seen these type of systems in the past be able to maintain hurricane status in SST 23-26C before in the Atlantic.

Also of note even with weakening from here on out, I highly doubt the winds in the upper reaches of the system will have died down in relationship to the surface. So I would expect to see our highest wind reports on the highest elevations of the archipelago.
DOOM

Quoting 530. TropicalAnalystwx13:

The fact about this El Nino is that we're nowhere close to an El Nino. The atmosphere isn't responding and even the equatorial East Pacific anomalies have been unstable. The subsurface warm pool has faded away to nothing in the absence of sustained westerly winds, and subsequent ones will do so the same until we get those winds. The issue is that sea surface temperatures along the entire equatorial Pacific (East, Central, West) are fairly uniform, meaning you're not getting that wind gradient you want to sustain westerly winds. Compare the average vs. what we're observing:



Need colder than normal Wpac for westerly winds to take over?
Iselle is GAINING EYESIGHT.

Quoting 530. TropicalAnalystwx13:
The fact about this El Nino is that we're nowhere close to an El Nino. The atmosphere isn't responding and even the equatorial East Pacific anomalies have been unstable. The subsurface warm pool has faded away to nothing in the absence of sustained westerly winds, and subsequent ones will do so the same until we get those winds. The issue is that sea surface temperatures along the entire equatorial Pacific (East, Central, West) are fairly uniform, meaning you're not getting that wind gradient you want to sustain westerly winds. Compare the average vs. what we're observing:




It's definitely an abnormal pattern setting up. You have elements of a warm ENSO phase, with a negative IOD and a slightly positive PDO.

I'd think that those upper clouds advancing toward Hawaii and the Iselle from the northwest are probably not a good sign for the storm as far as shear is concerned. She's already under a good amount of northeasterly shear as evident by the clouds streaming out of her to the southwest. Should see weakening at a decent clip once she crosses that advancing shear-axis (for lack of a better term) to her northwest. Assuming the Big Island doesn't take a significant toll on her first.



Feel free to correct me if my interpretation is off.
Quoting 530. TropicalAnalystwx13:

The fact about this El Nino is that we're nowhere close to an El Nino. The atmosphere isn't responding and even the equatorial East Pacific anomalies have been unstable. The subsurface warm pool has faded away to nothing in the absence of sustained westerly winds, and subsequent ones will do so the same until we get those winds. The issue is that sea surface temperatures along the entire equatorial Pacific (East, Central, West) are fairly uniform, meaning you're not getting that wind gradient you want to sustain westerly winds. Compare the average vs. what we're observing:



just curious cody.. why is the atlantic so hostile? low ssts? once again too much stable air? you think the atlantic this season will be climatologically average?

40N Latitude and points North have seen positive 1-2C SST anomalies against the CFSR 1981'-2010 Climatology for how many consecutive years now? It's really rather disturbing.
8/6/14



8/6/09



Does anyone remember when an El Nino event was officially declared in 2009?
Quoting 500. silas:

I'm still really surprised at how well Iselle has held up to the unfavorable conditions she's been facing, even if she doesn't look as good on satellite as she did several hours ago. I never thought she'd be nearing the Hawaiian islands still as a hurricane.



She sure looks ugly as all get out, at least compared to the Iselle we saw 72 hours ago, but she's fought horrible conditions for sustaining a tropical system and is still managing to stay cat 1. She deserves a medal! XD
Quoting 530. TropicalAnalystwx13:

The fact about this El Nino is that we're nowhere close to an El Nino. The atmosphere isn't responding and even the equatorial East Pacific anomalies have been unstable. The subsurface warm pool has faded away to nothing in the absence of sustained westerly winds, and subsequent ones will do so the same until we get those winds. The issue is that sea surface temperatures along the entire equatorial Pacific (East, Central, West) are fairly uniform, meaning you're not getting that wind gradient you want to sustain westerly winds. Compare the average vs. what we're observing:



Quoting 541. GTstormChaserCaleb:

8/6/14



8/6/09



Does anyone remember when an El Nino event was officially declared in 2009?


Again notice the difference in just 5 years at 40N latitude points north. Really has to have an affect on Tropical development when your refocusing rising air within these basins.
Quoting 538. HurrikanEB:

I'm no expert, but I've been around the block. . .
I'd think that those upper clouds advancing toward Hawaii and the Iselle from the northwest are probably not a good sign for the storm as far as shear is concerned. She's already under a good amount of northeasterly shear as evident by the clouds streaming out of her to the southwest. Should see weakening at a decent clip once she crosses that advancing shear-axis (for lack of a better term) to her northwest. Assuming the Big Island doesn't take a significant toll on her first.



Feel free to correct me if my interpretation is off.


edit. You are correct I guess shear is forecast to increase out of the northeast. Although I would have think a ULL to her west would implicate southwesterly shear. Got me.


LATEST SATELLITE IMAGES SHOW HIGH
CLOUDS STREAMING RAPIDLY SOUTHWEST FROM THE TOP OF ISELLE...WHICH
WOULD INDICATE IT IS CURRENTLY FEELING THE SHEARING EFFECTS OF THE
RIDGE TO THE WEST. THE FORECAST ANTICIPATES THE SHEAR TO INCREASE
AFTER 24 HOURS...LEADING TO A MORE RAPID WEAKENING.




Quoting 535. Gearsts:

Need a cool Wpac for westerly winds to take over?

Yes.

Quoting 539. wunderweatherman123:

just curious cody.. why is the atlantic so hostile? low ssts? once again too much stable air? you think the atlantic this season will be climatologically average?

Several factors. The AMO was negative for the first several months of 2014, leading to cooler waters across the tropical Atlantic and Caribbean. Even though the AMO has went very weakly positive since that time, the SST configuration has not changed much. Even though we don't have an El Nino in the Pacific, above-average waters there focus the upward pulse of the MJO (upper-level divergence) in that region, leading to the downward pulse of the MJO (upper-level convergence) in our basin. AIr that converges in the upper levels of the atmosphere sinks and dries out. Shear has slacked some lately, but active East Pacific convection produces upper-level outflow that enhances the TUTT across the Atlantic. And on top of it all, there have been several significant SAL outbreaks (which isn't really outside the realm of normalcy).
Genevieve was supposed to be our Category 5 here... a storm formed in our basin
went to become a category 5 beast somewhere else



Since 2010 we don't have a category 5 hurricane out there
Quoting 542. Huracan94:


She sure looks ugly as all get out, at least compared to the Iselle we saw 72 hours ago, but she's fought horrible conditions for sustaining a tropical system and is still managing to stay cat 1. She deserves a medal! XD
If it can maintain its current strength, there will likely be problems for many people in Hawaii. This system has carried with it huge amounts of moisture so far even with the large area of dry air.
Quoting 544. ILwthrfan:



Again notice the difference in just 5 years at 40N latitude points north. Really has to have an affect on Tropical development when your refocusing rising air within these basins.
Also at 40S. It's not as pronounced, but definitely there.


System in the Indian Ocean may need to be watched in a week or so as it crosses Africa into the Atlantic. Some of the GFS ensembles are picking up on that area.

Quoting 538. HurrikanEB:


I'd think that those upper clouds advancing toward Hawaii and the Iselle from the northwest are probably not a good sign for the storm as far as shear is concerned. She's already under a good amount of northeasterly shear as evident by the clouds streaming out of her to the southwest. Should see weakening at a decent clip once she crosses that advancing shear-axis (for lack of a better term) to her northwest. Assuming the Big Island doesn't take a significant toll on her first.



Feel free to correct me if my interpretation is off. iselle is a good wake up call for Hawaii. They should do a happy dance in October if they escape this season with just Iselle.
Quoting 550. GTstormChaserCaleb:



System in the Indian Ocean may need to be watched in a week or so as it crosses Africa into the Atlantic. Some of the GFS ensembles are picking up on that area.


I'm also looking at that area around 30W. Conditions are marginally more conducive than they were 2 weeks ago, so if this develops better vorticity it may have a chance later on down the road...
Quoting 548. hydrus:

If it can maintain its current strength, there will likely be problems for many people in Hawaii. This system has carried with it huge amounts of moisture so far even with the large area of dry air.



Waters are warmer the further west it goes too, which will help it pop up more thunderstorms and deeper convection as it heads towards the islands. Very likely there's going to be some rather bad flooding for some areas.
Quite an impressive train of Pacific cyclones out there. Don't forget about Halong either, he's ragged looking but different from a lot of West Pac recurving cyclones in that he shouldn't weaken much, and may even strengthen, on approach to Japan. Moving much slower than normal for a storm at his latitude also. He's been around for quite awhile, racking up a ton of ACE units.

Quoting 547. MaxWeather:

Genevieve was supposed to be our Category 5 here... a storm formed in our basin
went to become a category 5 beast somewhere else



Since 2010 we don't have a category 5 hurricane out there
If you are talking about the Atlantic we haven't had a Category 5 since Hurricane Felix.
556. beell

CIMSS 12Z Shear @ 12Z

THE GFS IS INDICATING THE RIDGE WEST OF HAWAII WILL SHIFT WEST AND MAINTAIN THE COL AND RELATIVELY LIGHT SHEAR NORTH OF ISELLE...WHILE THE ECMWF INDICATES LITTLE MOVEMENT OF THE RIDGE...INDICATING THAT STRONGER SHEAR LIES ALONG THE FUTURE PATH OF ISELLE. LATEST SATELLITE IMAGES SHOW HIGH CLOUDS STREAMING RAPIDLY SOUTHWEST FROM THE TOP OF ISELLE...WHICH WOULD INDICATE IT IS CURRENTLY FEELING THE SHEARING EFFECTS OF THE RIDGE TO THE WEST. THE FORECAST ANTICIPATES THE SHEAR TO INCREASE AFTER 24 HOURS...LEADING TO A MORE RAPID WEAKENING.
In revieuw of the 2013 hurricane season it was stated that the dry sable air in the MDR was due to faster trade winds , strong Bermuda high and finally the dry air from Brazil had moved across the MDR ,thereby inhibiting tropical development. To date there seems to be the anomaly of the stagnated dry stable air continuing to suppress convection in the MDR. There are other parameters beside which is known are responsible for this graveyard type environment in the MDR.
Meanwhile in California, this past week's flooding rains made an almost imperceptible dent in the unprecedented drought; 0.2% of the state (all along the Colorado River in the state's extreme southeast) "improved" from severe to moderate over the week. However, an additional 0.3% of the state worsened from severe to extreme. Overall, nearly 60% of the state remains in exceptional drought--the worst category.

So much for any help from Mother Nature.

Perhaps worse, the CPC's long-range outlook calls for conditions to persist or worsen from now through at least late autumn (when the state's climatological rainy season gets underway).





Quoting 553. Envoirment:



Waters are warmer the further west it goes too, which will help it pop up more thunderstorms and deeper convection as it heads towards the islands. Very likely there's going to be some rather bad flooding for some areas.
And do to the fact that it was one time annular, it may fight the S.W.shear that is forecast within the next 24 hours..
Quoting 557. stoormfury:

In revieux of the 2013 hurricane season it was stated that the dry sable air in the MDR was due to faster trade winds , high Bermuda high and finally the dry air from Brazil had moved across the Mdr ,thereby inhibiting tropical development. To date there seems to be the anomaly of the stagnated dry stable air continuing to suppress convection in the MDR. There are other parameters beside which is known are responsible for this graveyard type environment in the MDR.
Good post.

Is that weird line the edge of the International Date Line perhaps? I noticed that Genevieve is a typhoon now.
Iselle's winds are down to 80mph as of the new CPHC advisory. She's getting hammered, just too much dry air and shear. She probably won't survive as a hurricane to the Big Island. She's been very fun to track, especially in her annular stage, but we're seeing why it's so hard to hit Hawaii from the east. Impacts there should be minimal, especially if they catch the south side of the storm.

Still no 5am advisory from the CPHC?
JB is stating that the east carolinas north will be in the pattern highly favorable for landfall..

he says: The oldtimers called this pattern the Newfoundland wheel for it favored high pressure over the northwest Atlantic which mean storms underneath get caught and directed into the east coast of the US, often hitting moving north.. or west of north.

this is in accordance to the 11-15 day European Ensemble means..

Examples of storms he used:
Hazel
1955 Connie
Hugo
Fran
Isabel
Attn Florida casters- Three different hurricane threats in September according to the Farmer's Almanac.

Link
Quoting 565. MAweatherboy1:

Iselle's winds are down to 80mph as of the new CPHC advisory. She's getting hammered, just too much dry air and shear. She probably won't survive as a hurricane to the Big Island. She's been very fun to track, especially in her annular stage, but we're seeing why it's so hard to hit Hawaii from the east. Impacts there should be minimal, especially if they catch the south side of the storm.


I hope its minimal.
Quoting 565. MAweatherboy1:

Iselle's winds are down to 80mph as of the new CPHC advisory. She's getting hammered, just too much dry air and shear. She probably won't survive as a hurricane to the Big Island. She's been very fun to track, especially in her annular stage, but we're seeing why it's so hard to hit Hawaii from the east. Impacts there should be minimal, especially if they catch the south side of the storm.



Minimal is stretching it. This isn't Florida or North Carolina, it's a state that is not used to tropical cyclones even of this intensity. Even if winds at the surface manage to weaken below hurricane intensity, they'll still be screaming at higher altitudes (105 mph+ at 2000ft+). Hawaii is very mountainous, and people live at those higher terrains. Downsloping may also accelerate winds. But even ignoring that, orographic lift will wring out moisture; the CPHC is calling for 5 to 8 inches, with isolated totals over a foot. Flash flooding, mudslides, etc. all a concern.
Quoting 566. VAbeachhurricanes:

Still no 5am advisory from the CPHC?

Dangerous Iselle bearing down on the Big Island
SUMMARY OF 500 AM HST...1500 UTC...INFORMATION
LOCATION: 18.5N 150.6W
ABOUT 305 MI: 490 KM ESE OF HILO HAWAII
ABOUT 510 MI: 825 KM ESE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS: 80 MPH: 130 KM/H
PRESENT MOVEMENT: WNW OR 285 DEGREES AT 17 MPH: 28 KM/H
MINIMUM CENTRAL PRESSURE: 986 MB or 29.12 INCHES
Quoting 530. TropicalAnalystwx13:

The fact about this El Nino is that we're nowhere close to an El Nino. The atmosphere isn't responding and even the equatorial East Pacific anomalies have been unstable. The subsurface warm pool has faded away to nothing in the absence of sustained westerly winds, and subsequent ones will do so the same until we get those winds. The issue is that sea surface temperatures along the entire equatorial Pacific (East, Central, West) are fairly uniform, meaning you're not getting that wind gradient you want to sustain westerly winds. Compare the average vs. what we're observing:






True, but there is a second warm pool sliding east and its this that the CFS and Euro are picking up on and is the reason why those ensembles feel we will get El-Nino at some point. You have to understand that the longer we go without El-Nino the more heat that builds in the W-Pac and at some point that heat will have to be transferred east whether its this or next year or both years due to us not having El-Nino for 4 years. So with that said its possible not only will this year feature a low amount of storms but next year as well.
If you look at the annual precipitation map for the Islands, you can see how the topography and trade winds really focus the precipitation on the northeast side of the Islands.
The N.E. side of the Islands should also be the areas that see the most precipitation because of the wind direction and path of the system.



Quoting 550. GTstormChaserCaleb:



System in the Indian Ocean may need to be watched in a week or so as it crosses Africa into the Atlantic. Some of the GFS ensembles are picking up on that area.




I don't ever remember seeing such lack of convection as we have seen this year across the MDR
Quoting 574. StormTrackerScott:



I don't ever remember seeing such lack of convection as we have seen this year across the MDR
Could it be....EL NINO?
NOAA has lowered their forecast totals for this season to 7-12 named storms, 3-6 hurricanes, and 0-2 major hurricanes. There's a 70% chance of a below normal season, a 25% of a near normal season, and but a 5% chance of an above normal season (normal is 12-6-3).
Quoting 570. TropicalAnalystwx13:


Minimal is stretching it. This isn't Florida or North Carolina, it's a state that is not used to tropical cyclones even of this intensity. Even if winds at the surface manage to weaken below hurricane intensity, they'll still be screaming at higher altitudes (105 mph+ at 2000ft+). Hawaii is very mountainous, and people live at those higher terrains. Downsloping may also accelerate winds. But even ignoring that, orographic lift will wring out moisture; the CPHC is calling for 5 to 8 inches, with isolated totals over a foot. Flash flooding, mudslides, etc. all a concern.
. Yes. I'm very worried for my friends on the Puna district near Hilo and my friends who own homes on ridges near Honolulu. They are not use to these tropical systems. As we know these systems create major flooding in mountainous Caribbean and Mexico/Central American territories. I'm afraid we will see this type of major unprecedented flooding by these back to back storms. I lived in Hawaii for 7 years and it's the most beautiful place with the most beautiful people.
Nino will come, but It does seem that the cold water due to the winter temps in the S.E.Pacific have pushed close enough to the equator and up the coast to keep Nino at bay....for now...Some of it shows up here..



Quoting ncstorm:
JB is stating that the east carolinas north will be in the pattern highly favorable for landfall..

he says: The oldtimers called this pattern the Newfoundland wheel for it favored high pressure over the northwest Atlantic which mean storms underneath get caught and directed into the east coast of the US, often hitting moving north.. or west of north.

this is in accordance to the 11-15 day European Ensemble means..

Examples of storms he used:
Hazel
1955 Connie
Hugo
Fran
Isabel


He's correct. This is a fairly common pattern, known since at least the 1950s (1954 was a classic year for it).
Quoting 567. ncstorm:

JB is stating that the east carolinas north will be in the pattern highly favorable for landfall..

he says: The oldtimers called this pattern the Newfoundland wheel for it favored high pressure over the northwest Atlantic which mean storms underneath get caught and directed into the east coast of the US, often hitting moving north.. or west of north.

this is in accordance to the 11-15 day European Ensemble means..

Examples of storms he used:
Hazel
1955 Connie
Hugo
Fran
Isabel



That is quite a list. Ugh. Lots more development, even since Hugo in 1989.
Quoting 554. MAweatherboy1:

Quite an impressive train of Pacific cyclones out there. Don't forget about Halong either, he's ragged looking but different from a lot of West Pac recurving cyclones in that he shouldn't weaken much, and may even strengthen, on approach to Japan. Moving much slower than normal for a storm at his latitude also. He's been around for quite awhile, racking up a ton of ACE units.




Ha long has this been going on?
Quoting 576. unknowncomic:

Could it be....EL NINO?

It seems there's almost always a correlation with the Pacific being very active and the Atlantic remaining quiet durning the same period. Not always but close.
Quoting 567. ncstorm:

JB is stating that the east carolinas north will be in the pattern highly favorable for landfall..

he says: The oldtimers called this pattern the Newfoundland wheel for it favored high pressure over the northwest Atlantic which mean storms underneath get caught and directed into the east coast of the US, often hitting moving north.. or west of north.

this is in accordance to the 11-15 day European Ensemble means..

Examples of storms he used:
Hazel
1955 Connie
Hugo
Fran
Isabel

I respectfully disagree with JB the pattern showing up on the long range CFS shows the Subtropical Ridge extending all the way towards the East Coast of the US. The pattern resembles years like 1998, 2002, and 2007.
Quoting 579. KeyWestwx:

. Yes. I'm very worried for my friends on the Puna district near Hilo and my friends who own homes on ridges near Honolulu. They are not use to these tropical systems. As we know these systems create major flooding in mountainous Caribbean and Mexico/Central American territories. I'm afraid we will see this type of major unprecedented flooding by these back to back storms. I lived in Hawaii for 7 years and it's the most beautiful place with the most beautiful people.


I have a house at 2500 feet on Haleakalā in Kula Maui.
Keeping the fingers crossed.
Quoting 577. presslord:


Shut. Up.
Yep...The coastal Carolina,s is one of the roughest areas for sailors year round. Some the highest seas I ever saw were in the Gulf Stream S.W of Cape Hatteras...Big slow moving mountains with 12 footers on top...o Lordy.
Quoting 585. GTstormChaserCaleb:

I respectfully disagree with JB the pattern showing up on the long range CFS shows the Subtropical Ridge extending all the way towards the East Coast of the US. The pattern resembles years like 1998, 2002, and 2007.


I'm glad you can be respectful unlike others..
Quoting 586. cytochromeC:



I have a house at 2500 feet on Haleakalā in Kula Maui.
Keeping the fingers crossed.
that's such a beautiful area. Lots of Protea farms in area if I remember correctly. I'm worried for the homes way down stream. Many people down at the foot of the mountains may have waterfalls where they usually don't. The valleys at the base of the vertical mountains near Honolulu (Manoa e.g) may need to worry. I was just there hiking Lyon arboretum. I'm sure they will have major washouts and uprooted trees. Just go to goggle maps, Honolulu, and look at the topography of nearby towns nestled in these valleys surrounded by mountains. 😔
Quoting 589. ncstorm:



I'm glad you can be respectful unlike others..
I could be wrong though, but this pattern looks flat as it can ever be.

Quoting hydrus:
Nino will come, but It does seem that the cold water due to the winter temps in the S.E.Pacific have pushed close enough to the equator and up the coast to keep Nino at bay....for now...Some of it shows up here..





Even with an understanding on Ocean currents, its still pretty amazing that the water temperatures are that cold so close to the Equator off South America.
Another flareup on the northern semicircle of Iselle, with the infrared image showing the storm stubbornly reforming it's annular shape. All this is occurring while its been traversing sub 27 C waters and enduring some shear. It will return to 27 plus water just before landfall and the shear may lessen.
Did the CPHC never release a discussion??
Quoting unknowncomic:
Attn Florida casters- Three different hurricane threats in September according to the Farmer's Almanac.

Link


Is that the same book that's telling you south Florida is going to experience it's "typically drier" August this year?

Meanwhile, here in Sebring we got about about a 3"+ dump yesterday.

I'm seeing why you're unknown. :)

Quoting 594. VAbeachhurricanes:

Did the CPHC never release a discussion??

Can you not find anything by yourself, Mikey?

HURRICANE ISELLE DISCUSSION NUMBER 30
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092014
500 AM HST THU AUG 07 2014

ALTHOUGH THE SATELLITE PRESENTATION OF ISELLE HAS DEGRADED SLIGHTLY
OVER THE PAST COUPLE OF HOURS...A PERSISTENT EYE FEATURE CONTINUES
TO BE OBSERVED...AND ISELLE REMAINS A HURRICANE. DATA FROM AN AIR
FORCE RECONNAISSANCE AIRCRAFT CORROBORATE THE SLIGHT WEAKENING
TREND OBSERVED BY SATELLITE...AS MAXIMUM FLIGHT LEVEL WINDS IN THE
NORTHEAST QUADRANT DIMINISHED FROM 100 KT TO 85 KT OVERNIGHT...AND
MAXIMUM SFMR WINDS HAVE LOWERED TO NEAR 60 KT. BASED ON A BLEND OF
THE AIRCRAFT DATA AND SATELLITE INTENSITY ESTIMATES BETWEEN 4.0/65
KT AND 4.5/77 KT...THE INITIAL INTENSITY OF ISELLE IS BEING LOWERED
TO 70 KT FOR THIS ADVISORY.

INITIAL MOTION ESTIMATE IS 285/15 KT...WHICH HAS BEEN FAIRLY
CONSISTENT OVER THE PAST 12 HOURS...WITH ISELLE BEING STEERED BY A
MID LEVEL RIDGE TO THE NORTH. THE UPDATED FORECAST TRACK REMAINS
CONSISTENT WITH THE LAST SEVERAL FORECASTS IN THE SHORT TERM...AND
REMAINS IN GOOD AGREEMENT WITH THE MULTI-MODEL CONSENSUS...WHICH HAS
BEEN CONSISTENT IN DEPICTING LANDFALL ALONG WINDWARD BIG ISLAND
THIS EVENING. IN 36 TO 48 HOURS ISELLE IS EXPECTED TO REACH THE
WESTERN PERIPHERY OF THE RIDGE AS A WEAK CUT OFF LOW DIGS SOUTHWARD
ALONG THE FORECAST TRACK...RESULTING IN A SLOWING OF THE FORWARD
MOTION THROUGH 72 HOURS. AS THE LOW MOVES SOUTH AND ISELLE WEAKENS...
A NEW RIDGE ALOFT IS FORECAST TO BUILD NORTH OF THE WEAKENING
ISELLE...AND THE FORWARD MOTION WILL INCREASE ONCE AGAIN. THE
UPDATED FORECAST TRACK ONLY OFFERS MINOR CHANGES TO THE PREVIOUS...
AND CLOSELY FOLLOWS THE WELL-PERFORMING CONSENSUS TVCN.

THE INTENSITY FORECAST CALLS FOR ONLY SLIGHT WEAKENING BEFORE
LANDFALL TONIGHT...DESPITE THE FORECAST OF MODERATE NORTHWESTERLY
SHEAR BY SHIPS GUIDANCE. ISELLE REMAINS SOUTH OF A RIDGE ALOFT
CENTERED WEST OF THE MAIN HAWAIIAN ISLANDS AND A RIDGE CENTERED OVER
THE BAJA PENINSULA. A COL...OR WEAKNESS...BETWEEN THESE TWO RIDGES
PROVIDES A LIGHTER SHEAR ENVIRONMENT IN WHICH ISELLE WOULD BE ABLE
TO MAINTAIN THE CURRENT INTENSITY BEFORE LANDFALL...WHEREAS IF
ISELLE WERE TO MOVE WEST OF THE COL AND CLOSER TO THE RIDGE CENTERED
TO THE WEST...THE SHEAR PROFILE WOULD BE MORE DEBILITATING. THE
INTENSITY FORECAST PROBLEM IS THAT GLOBAL MODELS ARE OFFERING
DIFFERENT SOLUTIONS AS TO THE INTERACTION BETWEEN ISELLE AND THE
FLOW ALOFT IN THE SHORT TERM...WITH SOME SOLUTIONS TRACKING ISELLE
AND THE COL WESTWARD IN TANDEM...WHILE OTHERS MOVE ISELLE WEST OF
THE COL AND INTO AN AREA OF STRONGER SHEAR. INTERACTION WITH THE
TERRAIN OF THE BIG ISLAND IS EXPECTED TO WEAKEN ISELLE TONIGHT...
WHILE A SOUTHWARD-MOVING CUT OFF LOW DEVELOPING NORTHWEST OF THE
HAWAIIAN ISLANDS ON DAYS 2 AND 3 WILL BRING STRONGER SHEAR.
INTERACTION WITH THIS LOW IS EXPECTED TO LEAD TO THE DEMISE OF
ISELLE...WITH REMNANT LOW STATUS FORECAST BY DAY 5...CLOSELY
FOLLOWING THE TRENDS OFFERED BY THE SHIPS GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INIT 07/1500Z 18.5N 150.6W 70 KT 80 MPH
12H 08/0000Z 19.1N 152.9W 65 KT 75 MPH
24H 08/1200Z 19.8N 155.9W 55 KT 65 MPH...INLAND
36H 09/0000Z 20.5N 158.7W 50 KT 60 MPH
48H 09/1200Z 21.0N 161.0W 45 KT 50 MPH
72H 10/1200Z 22.5N 165.7W 40 KT 45 MPH
96H 11/1200Z 24.4N 171.1W 30 KT 35 MPH
120H 12/1200Z 27.0N 177.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$

FORECASTER BIRCHARD
There will be some spectacular waterfalls coming off the cliffs of Hawaii over the next few days. Akaka Falls is near Hilo, and near where the eye may make landfall, assuming there remains an eye in Iselle at that point.
El Nino issues aside for the moment, the Central Atlantic does not look very favorable at the moment for development so regardless of whether El Nino is declared or not, we may have some struggling storms in that region due to some of the same issues we saw last year; anomalous dry and stable air among others. I am thinking that the greatest potential threat this year for the US might come from a storm closer to home whether off of Florida or in the Gulf if shear cooperates during the peak period when SST's are at their highest. Temps around Florida and Gulf are well into the 80's at the moment with some readings in the Central Gulf as high as 87.

Both places (Gulf and Florida East Coast) have been very fortunate the past several years but development closer to home, whether from a wave/ts that struggles in Atlantic but finds better condition North of the Caribbean or in the Western Caribbean on the way into the Gulf, or a frontal or trof remnant, is something to keep a close eye (shear wise) until SST's start to back down again towards the end of September into October.
Quoting 596. TropicalAnalystwx13:


Can you not find anything by yourself, Mikey?

HURRICANE ISELLE DISCUSSION NUMBER 30
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092014
500 AM HST THU AUG 07 2014

ALTHOUGH THE SATELLITE PRESENTATION OF ISELLE HAS DEGRADED SLIGHTLY
OVER THE PAST COUPLE OF HOURS...A PERSISTENT EYE FEATURE CONTINUES
TO BE OBSERVED...AND ISELLE REMAINS A HURRICANE. DATA FROM AN AIR
FORCE RECONNAISSANCE AIRCRAFT CORROBORATE THE SLIGHT WEAKENING
TREND OBSERVED BY SATELLITE...AS MAXIMUM FLIGHT LEVEL WINDS IN THE
NORTHEAST QUADRANT DIMINISHED FROM 100 KT TO 85 KT OVERNIGHT...AND
MAXIMUM SFMR WINDS HAVE LOWERED TO NEAR 60 KT. BASED ON A BLEND OF
THE AIRCRAFT DATA AND SATELLITE INTENSITY ESTIMATES BETWEEN 4.0/65
KT AND 4.5/77 KT...THE INITIAL INTENSITY OF ISELLE IS BEING LOWERED
TO 70 KT FOR THIS ADVISORY.

INITIAL MOTION ESTIMATE IS 285/15 KT...WHICH HAS BEEN FAIRLY
CONSISTENT OVER THE PAST 12 HOURS...WITH ISELLE BEING STEERED BY A
MID LEVEL RIDGE TO THE NORTH. THE UPDATED FORECAST TRACK REMAINS
CONSISTENT WITH THE LAST SEVERAL FORECASTS IN THE SHORT TERM...AND
REMAINS IN GOOD AGREEMENT WITH THE MULTI-MODEL CONSENSUS...WHICH HAS
BEEN CONSISTENT IN DEPICTING LANDFALL ALONG WINDWARD BIG ISLAND
THIS EVENING. IN 36 TO 48 HOURS ISELLE IS EXPECTED TO REACH THE
WESTERN PERIPHERY OF THE RIDGE AS A WEAK CUT OFF LOW DIGS SOUTHWARD
ALONG THE FORECAST TRACK...RESULTING IN A SLOWING OF THE FORWARD
MOTION THROUGH 72 HOURS. AS THE LOW MOVES SOUTH AND ISELLE WEAKENS...
A NEW RIDGE ALOFT IS FORECAST TO BUILD NORTH OF THE WEAKENING
ISELLE...AND THE FORWARD MOTION WILL INCREASE ONCE AGAIN. THE
UPDATED FORECAST TRACK ONLY OFFERS MINOR CHANGES TO THE PREVIOUS...
AND CLOSELY FOLLOWS THE WELL-PERFORMING CONSENSUS TVCN.

THE INTENSITY FORECAST CALLS FOR ONLY SLIGHT WEAKENING BEFORE
LANDFALL TONIGHT...DESPITE THE FORECAST OF MODERATE NORTHWESTERLY
SHEAR BY SHIPS GUIDANCE. ISELLE REMAINS SOUTH OF A RIDGE ALOFT
CENTERED WEST OF THE MAIN HAWAIIAN ISLANDS AND A RIDGE CENTERED OVER
THE BAJA PENINSULA. A COL...OR WEAKNESS...BETWEEN THESE TWO RIDGES
PROVIDES A LIGHTER SHEAR ENVIRONMENT IN WHICH ISELLE WOULD BE ABLE
TO MAINTAIN THE CURRENT INTENSITY BEFORE LANDFALL...WHEREAS IF
ISELLE WERE TO MOVE WEST OF THE COL AND CLOSER TO THE RIDGE CENTERED
TO THE WEST...THE SHEAR PROFILE WOULD BE MORE DEBILITATING. THE
INTENSITY FORECAST PROBLEM IS THAT GLOBAL MODELS ARE OFFERING
DIFFERENT SOLUTIONS AS TO THE INTERACTION BETWEEN ISELLE AND THE
FLOW ALOFT IN THE SHORT TERM...WITH SOME SOLUTIONS TRACKING ISELLE
AND THE COL WESTWARD IN TANDEM...WHILE OTHERS MOVE ISELLE WEST OF
THE COL AND INTO AN AREA OF STRONGER SHEAR. INTERACTION WITH THE
TERRAIN OF THE BIG ISLAND IS EXPECTED TO WEAKEN ISELLE TONIGHT...
WHILE A SOUTHWARD-MOVING CUT OFF LOW DEVELOPING NORTHWEST OF THE
HAWAIIAN ISLANDS ON DAYS 2 AND 3 WILL BRING STRONGER SHEAR.
INTERACTION WITH THIS LOW IS EXPECTED TO LEAD TO THE DEMISE OF
ISELLE...WITH REMNANT LOW STATUS FORECAST BY DAY 5...CLOSELY
FOLLOWING THE TRENDS OFFERED BY THE SHIPS GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INIT 07/1500Z 18.5N 150.6W 70 KT 80 MPH
12H 08/0000Z 19.1N 152.9W 65 KT 75 MPH
24H 08/1200Z 19.8N 155.9W 55 KT 65 MPH...INLAND
36H 09/0000Z 20.5N 158.7W 50 KT 60 MPH
48H 09/1200Z 21.0N 161.0W 45 KT 50 MPH
72H 10/1200Z 22.5N 165.7W 40 KT 45 MPH
96H 11/1200Z 24.4N 171.1W 30 KT 35 MPH
120H 12/1200Z 27.0N 177.0W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$

FORECASTER BIRCHARD


It still says 11pm on their page :/
Thanks, cods.
Scanning the map of observation stations on the Big Island, I see nothing at the easternmost point, Cape Kumukahi. I guess they never figured that any significant weather would ever approach from that direction.
Quoting 597. BayFog:

There will be some spectacular waterfalls coming off the cliffs of Hawaii over the next few days. Akaka Falls is near Hilo, and near where the eye may make landfall, assuming there remains an eye in Iselle at that point.
I lived close to the mountains on the windward side of Oahu and just a small storm would create spectacular waterfalls. These will be epic!
Quoting 592. Sfloridacat5:



Even with an understanding on Ocean currents, its still pretty amazing that the water temperatures are that cold so close to the Equator off South America.
It is those cold waters that make the fishing a very lucrative business there. When Nino comes the fishing is poor to non existent, and the weather very bad.
JeffMasters has created a new entry.
Quoting 585. GTstormChaserCaleb:

I respectfully disagree with JB the pattern showing up on the long range CFS shows the Subtropical Ridge extending all the way towards the East Coast of the US. The pattern resembles years like 1998, 2002, and 2007.
I was thinking that too, but then I realized that as the year wears on, the troughs will be strong earlier than usual, causing storms to curve north, possibly affecting the U.S....As always tho, its timing, the strength of the Bermuda High, and the number and strength of the troughs.
Quoting 601. KeyWestwx:

I lived close to the mountains on the windward side of Oahu and just a small storm would create spectacular waterfalls. These will be epic!


Up for the Pali Lookout?
Quoting 590. KeyWestwx:

that's such a beautiful area. Lots of Protea farms in area if I remember correctly. I'm worried for the homes way down stream. Many people down at the foot of the mountains may have waterfalls where they usually don't. The valleys at the base of the vertical mountains near Honolulu (Manoa e.g) may need to worry. I was just there hiking Lyon arboretum. I'm sure they will have major washouts and uprooted trees. Just go to goggle maps, Honolulu, and look at the topography of nearby towns nestled in these valleys surrounded by mountains. 😔


Manoa can handle a lot of water, but this may be a historic event. A lot of water will be going down those drainage canals to the sea. I've seen them as raging torrents. It's possible roads and bridges get washed out.

If not for Oahu, possibly Hawaii or Maui. Time will tell. Let's hope for the best.
Quoting 606. HaoleboySurfEC:



Up for the Pali Lookout?
it's going to be one big Slip N Slide.
Quoting 573. Sfloridacat5:

If you look at the annual precipitation map for the Islands, you can see how the topography and trade winds really focus the precipitation on the northeast side of the Islands.
The N.E. side of the Islands should also be the areas that see the most precipitation because of the wind direction and path of the system.






But the backside of the storm could drop deluge on places not accustomed to it the"dry" side.. I would think that might raise landslide dangers a lot.
I know your doing the hurricane thing but this needs to be posted for the east coast of Florida folks..stay safe out there............................................. ..........SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
322 PM EDT THU AUG 7 2014

FLZ047-053-147-072000-
NORTHERN BREVARD COUNTY-OSCEOLA-SOUTHERN BREVARD COUNTY-
322 PM EDT THU AUG 7 2014

...FUNNEL CLOUDS POSSIBLE OVER BREVARD COUNTY...NORTHEASTERN OSCEOLA
COUNTY...

AT 318 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STORM CAPABLE OF PRODUCING FUNNEL CLOUDS...STRONG WIND GUSTS AND
FREQUENT TO EXCESSIVE LIGHTNING OVER CANAVERAL GROVES...MOVING
SOUTHEAST AT 10 MPH.

THIS STORM WILL CONTINUE TO BUILD SOUTHWARD DOWN THE EAST COAST SEA
BREEZE AND AFFECT AREAS NEAR INTERSTATE 95 DOWN TO COCOA...ROCKLEDGE
AND VIERA.

LOCAL ATMOSPHERIC CONDITIONS ARE BECOMING MORE FAVORABLE FOR THE
POSSIBILITY OF LANDSPOUT FORMATION. A LANDSPOUT IS A TORNADO OF VERY
SHORT DURATION AND WINDS GENERALLY LESS THAN 60 MPH WHICH CAN CAUSE
MINOR DAMAGE AND INJURIES IN ITS DIRECT PATH. STAY TUNED TO NOAA
WEATHER RADIO AND LOCAL MEDIA FOR ADDITIONAL UPDATES AND POSSIBLE
WARNINGS.