Tropical cyclone, Hurricane Season 2023

[vox_mundi]

Hurricanes Found to Push Warm Water Deep Into Ocean, Impacting Climate In Distant Locales
https://phys.org/news/2023-06-hurricanes-deep-ocean-impacting-climate.html



A team of oceanographers at the University of California's Scripps Institution of Oceanography, working with one colleague from Brandeis University and two from Oregon State University, has found evidence of typhoons/hurricanes pushing warm water deep into the ocean, where it is carried to distant places. In their research, reported in Proceedings of the National Academy of Sciences, the group studied ocean conditions before and after three typhoons over parts of the Philippine Sea.

Prior research has shown that typhoons and hurricanes get their start when warm water in the tropics evaporates into the air. Much research has explored the impact of such storms when they encounter human populated land areas, but little work has been done to learn more about the impact of such storms on the ocean.

To overcome that deficit, the team sailed throughout the Philippine Sea in the fall of 2018, during which three typhoons formed, stirring up the ocean. To learn more about their impacts, the team deployed probes deep into the sea to measure both water movement and temperature before and after a typhoon struck.

They found that each of the typhoons pushed warm surface water deep below the surface. They also caused churning of the water, mixing warm water from above with colder water from below. That was followed by underwater waves created by the typhoon pushing the warmer water downward and cooler water at the surface being rewarmed by the sun. The team found that the storms pushed the warm water to depths of 300 meters and that the heated water persisted for at least three weeks following a cyclone's passage.

The researchers also found that after the warm water was pushed downward, it was carried away by deep ocean currents—they found some evidence suggesting that the warm water from the storms was transported all the way to the coasts of Ecuador and California. Once there, it was transported to the surface by shoaling currents and turbulent mixing near the shore. They suggest that the movement of warm ocean water by typhoons and hurricanes could impact weather in distant locales as it makes its way back to the surface.

Noel Gutiérrez Brizuela et al, Prolonged thermocline warming by near-inertial internal waves in the wakes of tropical cyclones, Proceedings of the National Academy of Sciences (2023)
https://www.pnas.org/doi/10.1073/pnas.2301664120

[John Batteen]

Now THAT is pretty interesting!  Wonder if any of that is reaching the Arctic Ocean.

[vox_mundi]

Ekman pumping writ large

https://en.m.wikipedia.org/wiki/Ekman_transport

[kassy]

It is interesting indeed. From the conversation:

Hurricanes push heat deeper into the ocean than scientists realized, boosting long-term ocean warming, new research shows



When a hurricane hits land, the destruction can be visible for years or even decades. Less obvious, but also powerful, is the effect hurricanes have on the oceans.

In a new study, we show through real-time measurements that hurricanes don’t just churn water at the surface. They can also push heat deep into the ocean in ways that can lock it up for years and ultimately affect regions far from the storm.

Heat is the key component of this story. It has long been known that hurricanes gain their energy from warm sea surface temperatures. This heat helps moist air near the ocean surface rise like a hot air balloon and form clouds taller than Mount Everest. This is why hurricanes generally form in tropical regions.

What we discovered is that hurricanes ultimately help warm the ocean, too, by enhancing its ability to absorb and store heat. And that can have far-reaching consequences.

When hurricanes mix heat into the ocean, that heat doesn’t just resurface in the same place. We showed how underwater waves produced by the storm can push the heat roughly four times deeper than mixing alone, sending it to a depth where the heat is trapped far from the surface. From there, deep sea currents can transport it thousands of miles. A hurricane that travels across the western Pacific Ocean and hits the Philippines could end up supplying warm water that heats up the coast of Ecuador years later.

...

https://theconversation.com/hurricanes-push-heat-deeper-into-the-ocean-than-scientists-realized-boosting-long-term-ocean-warming-new-research-shows-206920

Slightly different accents in an article by two of the authors of the paper.

[vox_mundi]

It might have been a contributing factor to the blob along with the 2014 ENSO

Interestingly, the Pacific Blob of 2014/2015 was preceded by one of the busiest Pacfic hurricane/typhoon seasons.

https://en.m.wikipedia.org/wiki/2014_Pacific_hurricane_season

Two Category 4 hurricanes, of which one became the strongest tropical cyclone ever recorded in May, 2014 in the East Pacific. Overall, the 22 tropical storms marked the highest total in 22 years. In addition, a record-tying 16 hurricanes developed. Furthermore, there were total of nine major hurricanes, Category 3 or greater on the Saffir–Simpson hurricane wind scale, including a then-record-tying eight in Eastern Pacific proper (east of 140°W).

https://en.m.wikipedia.org/wiki/The_Blob_(Pacific_Ocean)

https://en.m.wikipedia.org/wiki/2014%E2%80%932016_El_Ni%C3%B1o_event

It might also explain fishery collapse following busy hurricane seasons.

[Sigmetnow]

Philip Klotzbach
Updated Atlantic seasonal #hurricane forecast from ⁦‪@ColoradoStateU‬⁩ calls for above-normal season: 18 named storms (including 4 that have formed), 9 hurricanes & 4 major hurricanes. Extremely warm tropical/subtropical Atlantic may dominate over #ElNino:
https://tropical.colostate.edu/Forecast/2023-07.pdf

7/6/23, 11:00 AM. https://twitter.com/philklotzbach/status/1676969269312258048

[John_the_Younger]

...18 named storms (including 4 that have formed)...

Funny, from a NOAA current season summary:

Summary Table

Name                      Dates              Max Wind (mph)
-----------------------------------------------------------
Unnamed STS**                                             
TS Arlene                 1-3 Jun                 40
TS Bret                 19-24 Jun                 70
TS Cindy                22-26 Jun                 60
-----------------------------------------------------------     

** An unnamed subtropical storm formed in mid January. Exact dates
and maximum winds will be provided once the post-storm analysis is
complete.

Because the January 16 storm wasn't recognized until after dissipation, it was not named, though through deficiencies in the English language, it included among the named.

[John_the_Younger]

NOAA forecast: Hurricane Calvin will reach Hawaii as a tropical storm while Tropical Storm Don is dancing a circle in the Atlantic.

[Rodius]

Concerning the Atlantic ocean heat situation.... at what point will all that energy turn into large hurricanes and reach Central and North America?

The El Nino, as I understand it, creates wind sheer that kills hurricanes as they near the Americas, but surely there comes a point where the hurricane size overwhelms the wind sheer?

Maybe this is a question for the hurricane thread?

[The Walrus]

Concerning the Atlantic ocean heat situation.... at what point will all that energy turn into large hurricanes and reach Central and North America?

The El Nino, as I understand it, creates wind sheer that kills hurricanes as they near the Americas, but surely there comes a point where the hurricane size overwhelms the wind sheer?

Maybe this is a question for the hurricane thread?

Actually, it is wind shear (or lack thereof) that is a major factor in the size and strength of hurricanes.  Water temperature is a minor contributor.

[Rodius]

Concerning the Atlantic ocean heat situation.... at what point will all that energy turn into large hurricanes and reach Central and North America?

The El Nino, as I understand it, creates wind sheer that kills hurricanes as they near the Americas, but surely there comes a point where the hurricane size overwhelms the wind sheer?

Maybe this is a question for the hurricane thread?

Actually, it is wind shear (or lack thereof) that is a major factor in the size and strength of hurricanes.  Water temperature is a minor contributor.

The energy for hurricanes has to come from somewhere... so ocean heat matters.
There are several factors that are required... wind shear is one.

So, all the excess heat in the Atlantic does matter and will be one factor that determines the strength of a hurricane. Given how much heat is there, that is worth the question of how much energy can overcome the EL Nino factor that reduces the number of hurricanes in a season.

https://oceanservice.noaa.gov/facts/how-hurricanes-form.html

Add on: The prediction of more than average hurricanes this season has been increased because of the extra heat in the Atlantic... so, yeah... the heat does matter enough to turn the lower number predictions from earlier in the year.

https://www.washingtonpost.com/weather/2023/07/06/revised-hurricane-season-forecast-atlantic-csu/

[GoodeWeather]

Concerning the Atlantic ocean heat situation.... at what point will all that energy turn into large hurricanes and reach Central and North America?

The El Nino, as I understand it, creates wind sheer that kills hurricanes as they near the Americas, but surely there comes a point where the hurricane size overwhelms the wind sheer?

Maybe this is a question for the hurricane thread?

Actually, it is wind shear (or lack thereof) that is a major factor in the size and strength of hurricanes.  Water temperature is a minor contributor.

I think you missed a class.  Water temp is just as important as wind shear when it comes to size and strength of a hurricane.  You can have a perfect wind shear environment, but if the water is on the cooler side, not much is going to happen.   

[kassy]

Maybe this is a question for the hurricane thread?

Yes since it involves delving into them more then ocean temps so i moved it.

[The Walrus]

Concerning the Atlantic ocean heat situation.... at what point will all that energy turn into large hurricanes and reach Central and North America?

The El Nino, as I understand it, creates wind sheer that kills hurricanes as they near the Americas, but surely there comes a point where the hurricane size overwhelms the wind sheer?

Maybe this is a question for the hurricane thread?

Actually, it is wind shear (or lack thereof) that is a major factor in the size and strength of hurricanes.  Water temperature is a minor contributor.

I think you missed a class.  Water temp is just as important as wind shear when it comes to size and strength of a hurricane.  You can have a perfect wind shear environment, but if the water is on the cooler side, not much is going to happen.

Go back to school for you.
SST is more important for development, but wind shear is the main factor in intensification.

"The amount of wind shear, i.e., the change of the wind with height, is one of the most commonly used predictors of tropical cyclone intensity change, with large amounts of wind shear generally being unfavorable for intensification."

https://www.aoml.noaa.gov/impact-of-wind-shear-on-tropical-cyclone-intensity/

"The ocean and atmosphere in the North Atlantic are coupled through a feedback mechanism that excites a dipole pattern in vertical wind shear (VWS), a metric that strongly controls Atlantic hurricanes."

https://www.nature.com/articles/s41598-019-44252-w

"Previous studies modeling the effects of vertical wind shear on tropical cyclone structure conclude the shear results in asymmetries within the vortex, inhibiting intensification"

file:///C:/Users/kz6hk2/Downloads/169136.pdf

... and finally,

"it can be concluded that the lower layer relative vorticity and meridional wind Vertical shear may be the most important factor affecting the strength of tropical cyclones."

https://iopscience.iop.org/article/10.1088/1755-1315/208/1/012060/pdf

[Rodius]

Concerning the Atlantic ocean heat situation.... at what point will all that energy turn into large hurricanes and reach Central and North America?

The El Nino, as I understand it, creates wind sheer that kills hurricanes as they near the Americas, but surely there comes a point where the hurricane size overwhelms the wind sheer?

Maybe this is a question for the hurricane thread?

Actually, it is wind shear (or lack thereof) that is a major factor in the size and strength of hurricanes.  Water temperature is a minor contributor.

I think you missed a class.  Water temp is just as important as wind shear when it comes to size and strength of a hurricane.  You can have a perfect wind shear environment, but if the water is on the cooler side, not much is going to happen.

Go back to school for you.
SST is more important for development, but wind shear is the main factor in intensification.

"The amount of wind shear, i.e., the change of the wind with height, is one of the most commonly used predictors of tropical cyclone intensity change, with large amounts of wind shear generally being unfavorable for intensification."

https://www.aoml.noaa.gov/impact-of-wind-shear-on-tropical-cyclone-intensity/

"The ocean and atmosphere in the North Atlantic are coupled through a feedback mechanism that excites a dipole pattern in vertical wind shear (VWS), a metric that strongly controls Atlantic hurricanes."

https://www.nature.com/articles/s41598-019-44252-w

"Previous studies modeling the effects of vertical wind shear on tropical cyclone structure conclude the shear results in asymmetries within the vortex, inhibiting intensification"

file:///C:/Users/kz6hk2/Downloads/169136.pdf

... and finally,

"it can be concluded that the lower layer relative vorticity and meridional wind Vertical shear may be the most important factor affecting the strength of tropical cyclones."

https://iopscience.iop.org/article/10.1088/1755-1315/208/1/012060/pdf

Soooo... given heat from teh ocean forms the hurricane, doesnt it stand to reason that more heat in the ocean can produce more or bigger hurrcanes?

And given this statement, it is fair to say that the increase heat in the Atlantic, which is mindboggling hot, it going to produce hurricanes.

My question is whether the heat in the oceans that creates the conditions for hurricanes is going to overwhelm the conditions that an El Nino creates to prevent them hitting land is enough to stop that from happening.

Since I gave an article that states the number of storms for the season has been increased and a factor for that increase is the heat in the Atlantic, the answer to my question is yes, that heat has become so high that there is more chances of hurricanes in spite of the El Nino conditions reducing the number.

That heat is a huge problem regardless of the El Nino event, it should be something to delve into rather than defend you position jsut because you want to be right and prove whatever point it is you are trying to prove.

[gerontocrat]

The way I read the literature is that El Nino and general increases in ocean heat apparently also means a lot more energy in the atmosphere that may increase the occurrence of unsettled conditions, e.g. increased vertical wind shear.

So when conditions are right, monsters are spawned, but that may not happen more often or even happen less often.

[neal]

El Niño produces stronger westerly wind at upper levels of the atmosphere across the tropical Atlantic than in normal non-El Niño seasons. This increases the total vertical wind shear, basically shearing the tops from developing storms before a healthy circulation can form.  El Niño events generally suppress Atlantic hurricane activity so fewer hurricanes than normal form in the Atlantic during August to October, the peak of Atlantic hurricane season./i]

https://www.weather.gov/jan/el_nino_and_la_nina#:~:text=El%20Ni%C3%B1o%20produces%20stronger%20westerly,a%20healthy%20circulation%20can%20form.

[The Walrus]

Concerning the Atlantic ocean heat situation.... at what point will all that energy turn into large hurricanes and reach Central and North America?

The El Nino, as I understand it, creates wind sheer that kills hurricanes as they near the Americas, but surely there comes a point where the hurricane size overwhelms the wind sheer?

Maybe this is a question for the hurricane thread?

Actually, it is wind shear (or lack thereof) that is a major factor in the size and strength of hurricanes.  Water temperature is a minor contributor.

I think you missed a class.  Water temp is just as important as wind shear when it comes to size and strength of a hurricane.  You can have a perfect wind shear environment, but if the water is on the cooler side, not much is going to happen.

Go back to school for you.
SST is more important for development, but wind shear is the main factor in intensification.

"The amount of wind shear, i.e., the change of the wind with height, is one of the most commonly used predictors of tropical cyclone intensity change, with large amounts of wind shear generally being unfavorable for intensification."

https://www.aoml.noaa.gov/impact-of-wind-shear-on-tropical-cyclone-intensity/

"The ocean and atmosphere in the North Atlantic are coupled through a feedback mechanism that excites a dipole pattern in vertical wind shear (VWS), a metric that strongly controls Atlantic hurricanes."

https://www.nature.com/articles/s41598-019-44252-w

"Previous studies modeling the effects of vertical wind shear on tropical cyclone structure conclude the shear results in asymmetries within the vortex, inhibiting intensification"

file:///C:/Users/kz6hk2/Downloads/169136.pdf

... and finally,

"it can be concluded that the lower layer relative vorticity and meridional wind Vertical shear may be the most important factor affecting the strength of tropical cyclones."

https://iopscience.iop.org/article/10.1088/1755-1315/208/1/012060/pdf

Soooo... given heat from teh ocean forms the hurricane, doesnt it stand to reason that more heat in the ocean can produce more or bigger hurrcanes?

And given this statement, it is fair to say that the increase heat in the Atlantic, which is mindboggling hot, it going to produce hurricanes.

My question is whether the heat in the oceans that creates the conditions for hurricanes is going to overwhelm the conditions that an El Nino creates to prevent them hitting land is enough to stop that from happening.

Since I gave an article that states the number of storms for the season has been increased and a factor for that increase is the heat in the Atlantic, the answer to my question is yes, that heat has become so high that there is more chances of hurricanes in spite of the El Nino conditions reducing the number.

That heat is a huge problem regardless of the El Nino event, it should be something to delve into rather than defend you position jsut because you want to be right and prove whatever point it is you are trying to prove.

Half right.  The added oceanic heat increases the time that conditions are ripe for tropical cyclone formation.  This is likely to produce more storms in a given season, as shown in the following paper which shows a "small nominally positive upward trend in tropical occurrance"

https://www.gfdl.noaa.gov/historical-atlantic-hurricane-and-tropical-storm-records/

However, the added heat does little to increase hurricane intensity, as wind shear is the dominant factor.  El Ninos produce strong westerly winds in the upper atmosphere, which tend to shear off the tops of these storms as they try to intensify.  Consequently, La Nina conditions are more favorable for hurricane intensification.

[Rodius]

The number of predicted storms has been increased from a few months ago... one of the stated reasons was the heat in the oceans.

I am not disputing what you are sharing though... I am saying that the people who do this for a job are saying this season will be above average in number of storms and strenght in spite of the El Nino.

It is not the expected prediction... as you say, EL Nino means less than average storms... but this year, it isnt the expected result.

We shall see how it pans out over the season

[The Walrus]

The number of predicted storms has been increased from a few months ago... one of the stated reasons was the heat in the oceans.

I am not disputing what you are sharing though... I am saying that the people who do this for a job are saying this season will be above average in number of storms and strenght in spite of the El Nino.

It is not the expected prediction... as you say, EL Nino means less than average storms... but this year, it isnt the expected result.

We shall see how it pans out over the season

It should be noted that this an average affect, not absolute.  SST has a greater influence on the number of storms formed, while ENSO has a greater effect on the intensity of those storms, but other factors contribute also  Hence, this season we could expect a greater number of storms due to higher temperatures, but less severity due to El Nino (depending on its strength). 

As you say, we shall see.

https://www.corelogic.com/intelligence/the-science-behind-the-storm-el-nino-and-the-2023-hurricane-season/

[Rodius]

The number of predicted storms has been increased from a few months ago... one of the stated reasons was the heat in the oceans.

I am not disputing what you are sharing though... I am saying that the people who do this for a job are saying this season will be above average in number of storms and strenght in spite of the El Nino.

It is not the expected prediction... as you say, EL Nino means less than average storms... but this year, it isnt the expected result.

We shall see how it pans out over the season

It should be noted that this an average affect, not absolute.  SST has a greater influence on the number of storms formed, while ENSO has a greater effect on the intensity of those storms, but other factors contribute also  Hence, this season we could expect a greater number of storms due to higher temperatures, but less severity due to El Nino (depending on its strength). 

As you say, we shall see.

https://www.corelogic.com/intelligence/the-science-behind-the-storm-el-nino-and-the-2023-hurricane-season/

This is going to be an interesting season. I feel like this could be a curve ball for hurricanes this year, but I have no idea what it will look like.

So interesting...

[KiwiGriff]

Modelling  finds Warmer sea resulting in an increase in severe cyclones while wind share is proposed to reduce the number cyclones over all.
The impact of storms is not linear   if you double the wind speed, you quadruple the force of the wind. An increase in  category four and five storms will be far more costly than we will benefit from a reduction in the number of storms over all .

https://www.researchgate.net/publication/215877210_Changes_in_tropical_cyclone_number_duration_and_intensity_in_a_warming_environment

We examined the number of tropical cyclones and cyclone days as well as tropical cyclone intensity over the past 35 years, in an environment of increasing sea surface temperature. A large increase was seen in the number and proportion of hurricanes reaching categories 4 and 5. The largest increase occurred in the North Pacific, Indian, and Southwest Pacific Oceans, and the smallest percentage increase occurred in the North Atlantic Ocean. These increases have taken place while the number of cyclones and cyclone days has decreased in all basins except the North Atlantic during the past decade.

[Jim Hunt]

Don has become the first North Atlantic hurricane of the 2023 season:

https://www.nhc.noaa.gov/archive/2023/al05/al052023.public.035.shtml

However he's not forecast to last long!

[John_the_Younger]

Not as a hurricane, anyway - but he's been a depression+ since July 14. [pre-hurricane status history of path plus latest windfield]

[gerontocrat]

Looks like Taiwan & SE China are going to get one.

[gerontocrat]

It looks like Typhoon Doksuri is turning into a real beast. You don't often see the forecaster getting really excited about a typhoon but this time....

The forecast rack keeps on edging westward so NE philippines could get a wallop on its way to Taiwan & SE China.
______________________________________________________________
https://www.metoc.navy.mil/jtwc/products/wp0523prog.txt
WDPN31 PGTW 230900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (DOKSURI) WARNING NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.9N 128.3E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 722 NM SOUTH-SOUTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANALYSIS OF ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
INDICATES THAT TYPHOON (TY) 05W (DOKSURI) HAS BEGUN TO RAPIDLY
INTENSIFY. THE ANIMATED MSI SUGGESTS THAT THE VORTEX REMAINS
SLIGHTLY TILTED, AS THE LOW LEVEL CIRCULATION CENTER (LLCC) CAN BE
SEEN WITHIN THE BROAD, RAGGED EYE, DISPLACED SLIGHTLY WEST OF THE
UPPER-LEVEL VORTEX CENTER. BUT THE INNER CORE IS RAPIDLY
CONSOLIDATING AND UNDERGOING AXISYMMETRIZATION, TAKING ADVANTAGE OF
A PERIOD OF LOW VERTICAL WIND SHEAR (VWS) AND STEADILY IMPROVING
UPPER-LEVEL OUTFLOW. THE MSI SHOWS DEEP CONVECTION IS STILL SPOTTY
AROUND THE NASCENT EYE FEATURE AND HAS AS OF THE 230700Z HOUR NOT
YET FORMED A COHERENT EYEWALL, BUT ITS ALMOST THERE. THE INITIAL
POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE VISIBLE
LOW-LEVEL STRUCTURE IN THE ANIMATED MSI. THE INITIAL INTENSITY AT
230600Z WAS ASSESSED WITH HIGH CONFIDENCE BASED ON T4.0 DVORAK
CURRENT INTENSITY ESTIMATES FROM PGTW, KNES AND RCTP, WITH
ADDITIONAL SUPPORT FROM THE ADT ESTIMATE OF 65 KNOTS AND A DPRINT
ESTIMATE OF 70 KNOTS. A HINT OF WHAT IS TO COME IS PROVIDED BY THE
ADT RAW, WHICH AS OF 230700Z IS ALREADY UP TO T5.7. ANIMATED WATER
VAPOR IMAGERY AND MESOSCALE ATMOSPHERIC MOTION VECTORS (AMVS)
DEPICT DRAMATICALLY IMPROVED UPPER-LEVEL OUTFLOW, PARTICULARLY TO
POLEWARD AS THE SYSTEM HAS DEVELOPED A POINT SOURCE OVER TOP OF THE
SYSTEM, ENHANCED BY CONTINUED FLOW INTO THE TUTT-CELL THAT REMAINS
NORTHEAST. OF NOTE, ANOTHER CUTOFF UPPER-LEVEL LOW IS SLIDING SOUTH
OF 30N TO THE EAST OF JAPAN AT PRESENT. THE OUTFLOW OF TY 05W HAS
NOT YET REACHED THAT FAR NORTH, BUT SOON WILL AND THEN THINGS WILL
GET REALLY EXCITING. IN ADDITION TO THE ROBUST OUTFLOW ENVIRONMENT,
THE SYSTEM SITS IN A POCKET OF LITTLE TO NO SHEAR AND IS MOVING
OVER ZESTY 30C WATERS WITH HIGH OHC EXCEEDING 90 KJ PER CM2 AND
GETTING HIGHER. TO SUM IT UP, CONDITIONS COULD NOT BE BETTER FOR
NEAR-TERM RAPID INTENSIFICATION (RI).

INITIAL WIND RADII BASIS: PERSISTENCE

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 60 KTS AT 230416Z
   CIMSS ADT: 65 KTS AT 230610Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE ONSET OF RI HAS BEEN MOVED
EARLIER IN THE FORECAST, THE PEAK INTENSITY HAS BEEN RAISED BY 10
KNOTS AND SHIFTED EARLIER IN THE FORECAST, WHILE THE TRACK
CONTINUES TO WALK SOUTHWESTWARD.

FORECAST DISCUSSION: TY 05W CONTINUES TO TRACK SLOWLY WESTWARD
ALONG THE SOUTHERN SIDE OF THE STR TO THE NORTH. CONTRARY TO
EARLIER FORECASTS, THE STR HAS NOT WEAKENED SIGNIFICANTLY, IN FACT
IT REMAINS VERY FIRMLY ENTRENCHED FROM THE EAST COAST OF HONSHU ALL
THE WAY TO SOUTHERN CHINA. HENCE, A GENERAL WESTWARD TRACK IS
EXPECTED FOR THE NEXT 24 HOURS. A DEEP UPPER-LEVEL LOW IS MOVING
ACROSS NORTHERN MANCHURIA AND DRAGGING A TROUGH ACROSS EASTERN
CHINA. THE GLOBAL MODELS CONTINUE TO INSIST THIS TROUGH WILL ERODE
THE STR ENOUGH TO GENERATE A BREAK IN THE RIDGE AFTER TAU 24, WHICH
WILL INDUCE TY 05W NORTHWARD. HOWEVER, THERE REMAINS A LARGE DEGREE
OF UNCERTAINTY INTO THE EXACT TIMING AND STRENGTH OF THE BREAK IN
THE RIDGE AND THE SUBSEQUENT TRACK OF TY 05W. THE FORECAST CALLS
FOR THE SYSTEM TO TURN NORTHWESTWARD BY TAU 36, CONTINUING ON THIS
TRACK THROUGH THE REMAINDER OF THE FORECAST. ON THE CURRENT TRACK,
LANDFALL ALONG THE SOUTHERN TIP OF TAIWAN IS ANTICIPATED BETWEEN
TAU 72 AND TAU 96 FOLLOWED BY A TRACKING INTO EASTERN CHINA BY TAU
120. IN TERMS OF INTENSITY, THE REAL SHOW IS ABOUT TO BEGIN. ONCE
THE OUTFLOW REACHES FAR ENOUGH NORTH TO ESTABLISH A CHANNEL INTO
THE UPPER-LEVEL LOW CURRENTLY DIVING SOUTH OF 30N, THE SYSTEM WILL
EMBARK UPON A PERIOD OF EXTREMELY RAPID INTENSIFICATION (ERI),
FUELED BY THE ROBUST OUTFLOW, LOW SHEAR AND VERY WARM, HIGH OHC
WATERS. THE CURRENT FORECAST CALLS FOR 60 KNOTS OF INTENSIFICATION
IN THE NEXT 48 HOURS, PEAKING AT LEAST AS HIGH AS 125 KNOTS BY TAU
48. A HIGHER PEAK AND HIGHER RATE OF INTENSIFICATION IS A DISTINCT
POSSIBILITY, DEPENDING ON HOW HIGH THE INTENSITY GETS BEFORE MOVING
INTO AN AREA OF SLIGHTLY COOLER, LOWER OHC WATERS JUST AFTER TAU
48. THE SYSTEM IS EXPECTED TO WEAKEN SLIGHTLY PRIOR TO LANDFALL DUE
TO REDUCTION IN THE OUTFLOW ALOFT AND SLIGHTLY INCREASED
NORTHEASTERLY SHEAR BUT WILL STILL BE A VERY POWERFUL TYPHOON UPON
LANDFALL.

MODEL DISCUSSION: WHILE THE MODEL ENVELOPE ITSELF HAS SHRUNK IN
TERMS OF CROSS-TRACK SPREAD, WITH ABOUT 215NM SPREAD AT TAU 72,
BOTH THE DETERMINISTIC TRACKERS AND THE ENSEMBLE MEANS CONTINUE
THEIR STEADY WALK TO THE WEST WITH THIS MODEL RUN. THE MULTI-MODEL
CONSENSUS MEAN NOW LIES OFF THE SOUTHWEST COAST OF TAIWAN, VERY
CLOSE TO THE ECMWF DETERMINISTIC TRACKER WHILE THE GFS AND GEFS
MEAN HAVE ALSO MOVED WEST BUT STILL LIE ON THE EASTERN SIDE OF THE
CONSENSUS ENVELOPE. OF NOTE, THE ECMWF DETERMINISTIC TRACK NOW
CLIPS THE NORTHEAST TIP OF LUZON AT TAU 60 BEFORE TURNING NORTH
TOWARDS TAIWAN AND THE NAVGEM TRACKER PERSISTS IN TAKING THE SYSTEM
INTO NORTH-CENTRAL LUZON. THE JTWC FORECAST SHIFTS WEST FROM THE
PREVIOUS FORECAST BUT REMAINS ON THE EAST SIDE OF THE CONSENSUS
MEAN THROUGH THE BULK OF THE FORECAST PERIOD. HOWEVER, IN LIGHT OF
THE PERSISTENT WESTWARD DRIFT AND WIDE SPREAD IN THE ENSEMBLE
MEMBERS, CONFIDENCE IN THE FORECAST TRACK REMAINS LOW, PARTICULARLY
AFTER TAU 72. THE BULK OF THE INTENSITY GUIDANCE IS IN GOOD
AGREEMENT ON A RI SCENARIO, WITH EVEN THE NORMALLY SLUGGISH
DECAY-SHIPS JUMPING ON BOARD. ADDITIONAL CONFIDENCE IS PROVIDED BY
THE 85 PERCENT RI PROBABILITY IN THE 230000Z COAMPS-TC ENSEMBLE RUN
AND THE FACT THAT EVERY ONE OF THE AVAILABLE RI AIDS IS SHOWING
EXTREMELY HIGH PROBABILITIES, BEYOND THAT SEEN IN ANY OTHER STORM
TO DATE. THUS, THE JTWC INTENSITY FORECAST OF RI IS MADE WITH HIGH
CONFIDENCE, THOUGH THE PEAK COULD BE EVEN HIGHER THAN CURRENTLY
ANTICIPATED. CONFIDENCE IN THE INTENSITY FORECAST BEYOND TAU 72 IS
MEDIUM DUE TO UNCERTAINTIES ASSOCIATED WITH VERY INTENSE TYPHOONS
INCLUDING POTENTIAL EYEWALL REPLACEMENT CYCLES (EWRC).

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: HIGH
   INTENSITY 72-120 HR: MEDIUM//

[gerontocrat]

As each day passes the forecast track of Typhoon Doksuri edges closer to the Philippines.

[John_the_Younger]

Hurricane Dora intensifying in the Pacific. Looks to me like it’ll go well south of Hawaii.

[be cause]

There seems no agreement in forecasts @ what typhoon Kahnun , approaching China atm , does next . Forecasts vary from a rapid decline as it moves away , to 10 days near stationery , churning over busy shipping lanes .

[be cause]

Having battered Okinawa , leaving death and destruction in it's wake , 400,000 residents have been ordered to leave their homes as typhoon/tc Kahnun returns .

[Sigmetnow]

Mike Masco
⁦‪🌀HURRICANE SEASON ABOUT TO GET ACTIVE
Interesting features showing in the medium range (mid to late AUG).
1. Prominent trough over the Midwest w/ axis to the TN valley
2. Established Mid Atlantic Ridge/ Trough over UK
3. Blocking Ridge over Greenland
 
If a tropical disturbance is able to stay far enough south it could pose a major threat to the SE USA as the interior east trough looks negatively tilted and will act as a magnetic to pull energy west vs out to sea. The ridges I noted above would guide such a storm NW/WNW depending on their strength and position.
 
.. This is a pattern you never want to sleep on moving into the most active portion of hurricane season.
8/4/23, 5:59 AM. https://twitter.com/mikemasco/status/1687402934672171008

[Sigmetnow]

Jim yang ⁦‪@yangyubin1998‬⁩
Typhoon Lan is likely to hit the Kanto region of Japan on August 15. This northward typhoon is generally very strong and may become the strongest typhoon to land in East Asia this year.
8/10/23, https://twitter.com/yangyubin1998/status/1689607728644452353

[gerontocrat]

Sonce yesterday I can't connect to the US Navy's JJoint Typhoon Warning Center at https://www.metoc.navy.mil/jtwc/jtwc.html

Anybody else having the same problem?

[vox_mundi]

It works OK for me

[Sigmetnow]

Greg Diamond ⁦‪@gdimeweather‬⁩

Dora is about to do something that has only been done once before (that we know of)

Stay at hurricane strength in the East, Central and West Pacific Basin.

And as a result, it will get a new name - Typhoon Dora!

Just a remarkable storm
 
8/11/23, 1:48 PM. https://twitter.com/gdimeweather/status/1690057612333588499

[vox_mundi]

Something may be peeking in a week or so ...

[RoxTheGeologist]

Question - as you guys know I am not really an expert - and definitely not on weather.

It seems to me that the temperature of the seawater not only increases the number of storms but also it has a baring on the rapid intensification of storms. Anecdotally I remember that there have been statements expressing surprise at how quickly storms have intensified over the last couple of seasons.

Increased wind shear from El Nino will reduce the intensity of storms, but if they are growing 3x as quickly, then it doesn't need 72 hours for hurricanes to grow from a 2 to a 5, but only 24 hours. In that case isn't much more likely that the required conditions will exist to grow big storms, despite the wind shear?

[The Walrus]

Question - as you guys know I am not really an expert - and definitely not on weather.

It seems to me that the temperature of the seawater not only increases the number of storms but also it has a baring on the rapid intensification of storms. Anecdotally I remember that there have been statements expressing surprise at how quickly storms have intensified over the last couple of seasons.

Increased wind shear from El Nino will reduce the intensity of storms, but if they are growing 3x as quickly, then it doesn't need 72 hours for hurricanes to grow from a 2 to a 5, but only 24 hours. In that case isn't much more likely that the required conditions will exist to grow big storms, despite the wind shear?

No, rapid intensification will only occur in the absence of wind shear. 

[Richard Rathbone]

Question - as you guys know I am not really an expert - and definitely not on weather.

It seems to me that the temperature of the seawater not only increases the number of storms but also it has a baring on the rapid intensification of storms. Anecdotally I remember that there have been statements expressing surprise at how quickly storms have intensified over the last couple of seasons.

Increased wind shear from El Nino will reduce the intensity of storms, but if they are growing 3x as quickly, then it doesn't need 72 hours for hurricanes to grow from a 2 to a 5, but only 24 hours. In that case isn't much more likely that the required conditions will exist to grow big storms, despite the wind shear?

High SST is why forecasters are predicting an average season despite it being El Nino. It won't overwhelm shear, but it  will offset it a bit. For a discussion on how the opposing factors might play out see:

https://yaleclimateconnections.org/2023/08/clash-of-the-titans-hurricane-forecasters-lay-odds-on-an-epic-battle/

[John_the_Younger]

Southern California, USA and Baja California, Mexico should get lots of rain from Hilary next week:

[gerontocrat]

Lots of comment and articles about the extent that high Atlantic SSTs counteract the megative El Nino effect on frequency of Atlantic storms & hurricanes.

Here is a gif of maps at 5 year intervals from 1998 to 2023 of the depth of 26 degree water in the North Atlantic (all at 17 August).

To me, one thing is for sure - as the years go by the area in which hurricanes can form increases.

link: http://isotherm.rsmas.miami.edu/heat/weba/atlantic.php

click gif to start, runs 6 times

[Jim Hunt]

The NHC North Atlantic 7 day outlook is very colourful this evening:

[The Walrus]

Yes, three different colors for the three different areas, each with different forecasts.

First, the yellow will experience some very dry air.  Hence development is unlikely, although the Gulf coasy could seem plentiful rainfall.  Might be beneficial for Texas and Mexico.

The orange area could develope into a depression and affect the lesser Antilees.  Warm seas and dry air will battle it out for dominance with this system.  Again, abundant rain for the islands.

The red area has the highest chance for development.  Conditions are more favorable there, but much depends on its movement.

[gerontocrat]

I remember not so long ago a large low in the Gulf of Mexico causing immense flooding

You don't always need a hurricane to cause a big problem.

[Jim Hunt]

Your Hilary track is auto updating John?

Here's the current state of play (2023-08-18 15Z) in the Eastern Pacific:

[vox_mundi]

Hurricane Hilary Could Dump Over a Year’s Worth of Rain On Parts of the Southwest
https://www.nhc.noaa.gov/text/refresh/MIATCPEP4+shtml/180552.shtml?

Concern is growing Hurricane Hilary will unleash a prolific amount of flooding rainfall on the southwestern US and parts of California as it makes a rare move over the region Sunday and into early next week, triggering the first ever tropical storm watch for California.



Hilary could dump more than a year’s worth of rain in parts of three states: California, Nevada and Arizona. Because of the threat, parts of California face a rare high risk for excessive rainfall. This Level 4 of 4 threat is the first to ever be issued for this part of Southern California

Hilary was a powerful Category 4 hurricane churning about 360 miles south of Cabo San Lucas, Mexico, Friday afternoon with sustained winds of 145 mph with stronger gusts, the National Hurricane Center said.

The storm underwent incredible rapid intensification Thursday into Friday, strengthening from a tropical storm to a Category 4 hurricane in just 24 hours. Hilary is forecast to remain a Category 4 as it approaches Mexico’s Baja California peninsula through Saturday.

Hilary is more likely to make landfall in Mexico and cross into California, but if it makes landfall in California as a tropical storm, it would be the first such storm to make landfall in California in nearly 84 years, according to data from the National Oceanic and Atmospheric Administration.

Heavy rainfall is expected to begin impacting the Southwest Saturday and through early next week, with the most intense downpours likely on Sunday and Monday.



It’s hard to overstate how big of a deal the high risks for excessive rainfall is. High risks are issued on fewer than 4% of days per year on average, but are responsible for 83% of all flood-related damage and 39% of all flood-related deaths, research from the Weather Prediction Center shows.

Thanks to Hilary, “multiple years’ worth of precipitation could potentially fall in some of the driest parts of California,” Daniel Swain, a climate scientist at the University of California at Los Angeles, said Wednesday.

Among those spots is Death Valley, California, the hottest place on Earth. Death Valley typically receives about 2 inches of rain across an entire year, according to NWS data. Moisture from Hilary could unleash enough rain to give Death Valley 1 to 2 years worth of rainfall in a single day. And Las Vegas could get 2 to 4 inches of rain. It only averages 3.75 inches of rain a year.

[Sigmetnow]

Tomer Burg ⁦‪@burgwx‬⁩
 
To sum up Hilary's rarity:
 
➡️ First time NHC has ever issued a Tropical Storm Watch in California
 
➡️ First WPC excessive rainfall high risk in the southern CA desert
 
➡️ Potential first tropical storm landfall in CA since 1939
 
This has potential to be a high-end event for CA.
  —
Hilary's biggest flooding concern extends well beyond the metropolitan coast - record-breaking moisture is expected to produce exceptional rainfall across large swaths of desert regions in CA & NV not accustomed to such rain totals, even in the winter.
8/18/23, 11:16 AM. https://x.com/burgwx/status/1692556135243424084

 
Russ Schumacher ⁦‪@russ_schumacher‬⁩
The ⁦‪@NWSWPC‬⁩ 7-day precipitation forecast shows spots with over 10.5" [268mm] of rain in southern California. Which would be more than 10" above the average precipitation during the next week...
8/18/23, 11:23 AM https://x.com/russ_schumacher/status/1692557817310240948

[be cause]

  atm enjoying 10mm p/h and a gale , tropical origins
   
Back on 28 July I warned fb friends in Ireland of 'what wanted to be a hurricane ' giving us a visit . On cue Antoni was named and passed overhead on the way to hammer Scandinavia as Hans !
 Now 10 days out GEM forecast shows 3 developing tropical depressions all potentially coming our way . A developing low with tropical roots is forecast to be on our doorstep by then too . 

[Jim Hunt]

  atm enjoying 10mm p/h and a gale , tropical origins

We've had the wind and rain. Albeit not as much of the latter as you.

Now we have sh1t in the sea all around the coast of SW England:

https://West-Devon.info/2023/08/storm-betty-barrels-towards-the-uk/

[be cause]

shit spreaders have been on the land here .. last 2 days farmers have covered the land in slurry , just in time to get washed into streams and rivers .
  btw .. heard Ireland belatedly named the storm Betty .. after my mum . Yesterday I couldn't visit her as covid lockdown had closed her acute care unit .. so she visited me ...