Weather Chat Megathread

[Just Jim]

We were in a feeder band north of the storm, and it rained pretty much all day. but nothing too bad. Just really wet. 

[IncongruousGoat]

Meanwhile, in the northeast, we have ourselves another heat wave. Heat index here was somewhere up around 100 today. On the bright side, it's almost certainly the last one of the season. Not because of any particular meteorological thing, but because summer is nearly over. Thank goodness.

Of course, I said that about the last heat wave, and then this happened...

[ProtoJeb21]

The latest Hurricane Hunters data is...concerning. Gordon’s central pressure has dropped by at least 2 mbar, and its winds have increased to 50 kts (60 mph). One of the Hurricane Hunters craft has found winds of up to 55-60 kts (65-70 mph) in parts of the storm north of the center. Tropical Storm Gordon may become a hurricane sooner than expected. 

[ProtoJeb21]

Good news: it looks like Tropical Storm Gordon will not become the Atlantic’s third hurricane this year. That title has just been taken by newly upgraded Hurricane Florence, which has unexpectedly intensified to an 85 mph Category 1 storm. Gordon has also strengthened a bit to 70 mph, but there is too little time for it to become a hurricane before making landfall tonight. 

The 2018 Pacific Hurricane season has just hit a major milestone: it has become the 10th most intense/active Pacific season in recorded history in terms of Accumulated Cyclone Energy. As of the latest NHC advisories for Hurricane Norman and Hurricane Olivia, there has been an impressive 185 units of ACE so far, about 85% higher then all of last year and the most in the East Pacific basin since 2015. If this season’s pace continues for the next month or two, it could easily be among the top 5. I expect a final ACE total of at least 200-210 and at least 20 named storms 12 hurricanes, and 8 major hurricanes by the end of the season. 

Back onto the individual storms, Hurricane Norman is still holding on despite wind shear and cooler waters. Unlike Miriam, its convection has yet to be torn apart from its center of rotation. The NHC expects it to remain a Category 1 for another day and a half to two days. Behind Norman is rapidly intensifying Hurricane Olivia, which has just become the sixth major hurricane of the 2018 Pacific season with winds of 120 mph. It has a chance to become yet another Category 4 hurricane before gradual weakening starts late tomorrow or Thursday. Based on current infrared satellite imagery, Olivia looks pretty close to doing so. 

Some final thoughts on the Atlantic: Hurricane Florence is set to become a tropical storm again tomorrow, but will return to hurricane status later this week as it enters a large area of 28-29 C waters off the US East Coast. Models are still in disagreement about whether or not it will threaten land. Meanwhile, Invest-92L is looking much more likely to develop into the next named storm, with the NHC now giving it an 80% chance of development during the next five days. They say that it will likely become a tropical depression or storm between late week and thand weekend. The next available name is Helene. After 92L, there will likely be another strong tropical wave coming off of Africa, and most models say that it will develop and could become stronger than Future Helene. It would likely get the name Issac, depending on whether or not a predicted area of low pressure will form and develop in the southwestern Caribbean. Suffice to say, this is going to be one active September. 

[cubinator]

It is rainy today.

[ProtoJeb21]

Both Hurricane Norman in the Central Pacific and Hurricane Florence in the Atlantic have become Category 3 major hurricanes. Norman, despite being uncomfortably close to high wind shear, has managed to rapidly re-organize and reach major hurricane status for the third time during its eight-day life so far. Even though it’s close to Hawaii, wind shear and strong steering will keep it away. Norman currently has winds of 115 mph and may get a little stronger before weakening. 

Unlike Norman, Hurricane Florence is definitely concerning. Its intensification makes even less sense than Norman’s, because it’s being plagued by both dry air and wind shear. It’s quite unexpected that it has managed to rapidly intensify like this. Florence currently has 120 mph winds — slightly stronger than Norman — and should start weakening a bit due to the previously mentioned dry air and wind shear. By Friday or Saturday, though, it will be in very favorable conditions and will likely reach major hurricane status again. After that, its future is uncertain. It could be drawn up north and taken out to sea, or it could be drawn into the eastern US by a ridge of high pressure. It may also just stall for a few days near Bermuda due to the opposing forces of opposite steering factors. If the second or third scenario happens, Florence will impact land (either the US or Bermuda) and has a good shot of becoming a Category 4 hurricane due to low wind shear and high SSTs of around 29 C. If the first scenario occurs, we would still have to keep an eye on Florence to see how close it gets to the Northeast or Atlantic Canada (Nova Scotia and Newfoundland). 

[ProtoJeb21]

4 hours ago, ProtoJeb21 said:

Florence currently has 120 mph winds — slightly stronger than Norman — and should start weakening a bit due to the previously mentioned dry air and wind shear.

I take that all back. Hurricane Florence is now a Category 4 with winds of 130 mph according to Tropical Tidbits, and it may be slightly stronger by the time of the NHC’s advisory. This is getting me very concerned for when Florence gets into more favorable conditions at the end of the week. 

[ProtoJeb21]

Finally, Hurricane Florence is behaving as expected and is now weakening due to strong wind shear. Most of the system’s convection has been displaced to the north, leaving the small core partially exposed. It should bottom out as about an 80-85 mph Category 1 hurricane before it moves out of the patch of wind shear by the first half of Saturday. There, it will reach an area with little to no wind shear and highly favorable SSTs, which is expected to cause it to regain major hurricane status. How strong it gets depends on its speed. The current NHC forecast cone has Florence slow down south of Bermuda this weekend due to conflicting steering currents. This is the same time as the storm’s environment become very conductive, so it may be able to surpass its initial peak intensity. That’s not good no matter where this storm goes, because it’s still going to be too close for comfort to Bermuda. After that, though, it’s anyone’s guess where it ends up. Yesterday the GFS model had Florence become an 895 mbar Category 5 right off the East Coast for like two days, which is a fine example of how ridiculous the model can get under high uncertainties. 

Florence won’t be the only system to worry about. Invest-92L is getting very close to developing, with a 70% chance of becoming a tropical depression or storm by Saturday. The problem with 92L is that it’s going to continue moving west and barely gain any latitude. This will put it on a direct path towards the Leeward Islands, including Barbuda, which was hit by Category 5 Hurricane Irma a year ago to the day (if I remember correctly).

In the East Pacific, both Hurricane Norman and Hurricane Olivia are Category 3s. Norman has maintained its major hurricane status for longer than expected and will start weakening for the final time tonight. Meanwhile, Olivia has started a second phase of rapid intensification. Its appearance on infrared satellite imagery has greatly improved, developing a large ring of powerful thunderstorms with cloud top temps around -70 C and a shrinking, better defined eye. It may be starting to intensify into the sixth Category 4 or above Hurricane this year in the Pacific, and like Norman, Lane, and Hector, Olivia will likely become another long-lasting high-ACE Hawaii-approaching storm. 

[tater]

 

[ProtoJeb21]

Invest-92L and Invest-93L off the coast of Africa are both about to develop, each with a 90% chance of becoming a depression or named storm within the next five days, and a 70-80% chance during the next two days. Which one develops first remains to be seen, but they will likely get the names Helene and Issac (the latter should’ve been retired back in 2012 by the way). 92L will continue due west and almost certainly impact parts of the Caribbean, including islands clobbered by Hurricanes Irma and Maria last September. 93L looks like it’ll follow Hurricane Florence (which is now a Cat 1 but should start restrengthening this weekend) and end up in the open ocean for some time. It may or may not end up affecting land. 

[ProtoJeb21]

I forgot to mention that today, the 2018 Pacific Hurricane Season has surpassed 200 units of ACE. Because of this, I’m going to slightly update my predictions for this year’s total storms and ACE. By the end of the year I’m expecting...

20-22 named storms

10-14 hurricanes 

8-12 major hurricanes

7-9 Category 4+ hurricanes

220-260 units of ACE

The reason I included the “Category 4+” section is because of how many storms have fit into that group this year. Literally EVERY major hurricane in this year’s Pacific Hurricane Season has been a Category 4 or above (Olivia just reached 130 mph winds and may get a bit stronger). No matter how accurate my predicts are exactly, 2018 is easily going to be among the most active and intense seasons in terms of both total storms and Accumulated Cyclone Energy. 

UPDATE: A new tropical depression just formed in the West Pacific, and it’s...very concerning. It’s at a low latitude and will stay around that same latitude for the next 5-8 days. This will take it through some of, if not the most favorable conditions in all of teh West Pacific, meaning an extremely powerful storm is guaranteed. The current forecast for the storm has it becoming a 155 mph Category 4 Super Typhoon early next week, and it may reach that intensity sooner. I thought the GFS model was ridiculous as normal for predicting an 869 mbar Super Typhoon for late next week, but now I think...it may be somewhat right. This little tropical depression could become an absolute monster that would make some of the other stronger storms this year look almost weak by comparison. I’m not saying this will surpass Super Typhoon Tip or Hurricane Patricia as the stronger tropical cyclone ever recorded, but a <900 mbar Category 5 looks pretty likely. 

[ProtoJeb21]

@SaturnianBlue Potential Tropical Cyclone Eight is now Tropical Depression Eight, and Invest-92L is now Tropical Depression Nine. Both are expected to become at least Category 1 hurricanes within the next five days. TD8 will be the first to become a tropical storm and will get the name Helene. It looks like it will be a Florence copycat and take an almost identical path over the next 4-7 days. TD9, on the other hand, is heading straight for the Caribbean. It appears to be facing some shear and as a result will reach tropical storm status later than TD9, meaning it will get the name Issac. However, wind shear should be decreasing soon, and future Issac will be heading into favorable conditions over the next few days, where it may be able to quickly intensify. What really unsettles me is its track and timeframe are a little too similar to Hurricane Maria...please, weather, have mercy. 

Tropical Storm Florence has recently stopped weakening as wind shear has passed its maximum. It should hold 65 mph winds for the next ~36 hours before starting to intensify again. The current NHC forecast has it becoming a Category 4 again by September 12th, but it may intensify quicker and sooner. If the GFS model is at least partially correct, Florence will surpass its first peak and most likely make landfall between South Carolina and Virginia. Then again, it’s a week out, so things are still pretty uncertain, but the chance of an East Coast strike is starting to get more likely. 

[ProtoJeb21]

Recently upgraded Tropical Storm Helene, formerly TD8, is starting to quickly strengthen and is threatening the Cabo Verde islands. There are now Hurricane Warnings for the southern islands since Helene is expected to soon become a hurricane. I think this may be only the second time this has ever happened, after 2015’s Hurricane Fred. 

Now, time for Hurricane Florence: I think it’s appropriate to panic now. There is far more confidence of an East Coast landfall, and the current NHC forecast has it becoming a 145 mph Category 4 hurricane right off of the North Carolina coast in five days. Also, because Florence will be riding the edge of a ridge of high pressure, it will likely go through and impact most of the East Coast, including where I live. 

[ProtoJeb21]

Despite battling some dry air and the last remaining significant wind shear, Florence appears to be strengthening. Its connective structure has become more symmetrical again, and an eye-like feature is forming. Currently, a Hurricane Hunters recon flight is in the storm, and on its most recent pass through the core it has found a pressure of 989.5 mbar and maximum sustained winds of about 60-65 knots (70-75 mph). It looks like Florence is just about to return to hurricane intensity, about six to eight hours faster than expected. 

[DarkOwl57]

So it's been raining...

And Raining...

And rain- oh hey, it stop- wait no nevermind, it's still raining

It's been raining non-stop from Tuesday all the way to now basically. Forecasts show it'll stop maybe Tuesday- the day after my second cross country meet. My first? Also filled with rain. Is this because of the tropical storm that hit to the east? (I live in West Texas for reference)

[ProtoJeb21]

Tonight, I decided to make a much larger analysis of the tropics than normal to go into far greater detail about the three named systems in the Atlantic. Feel free to critique this or add your own thoughts and predictions.

ATLANTIC MAPS

TROPICAL STORM FLORENCE

Florence has started to finally re-intensify. Based on an aircraft recon flight this afternoon, the NHC has upgraded it to a 70 mph tropical storm with a central barometric pressure of 989 mbar, almost at Category 1 hurricane intensity. It should become a hurricane within the next twelve hours or less. However, Florence has currently been fighting some dry air that managed to sneak into its center, which has caused the now-symmetrical convection to become less potent. The storm should be able to eventually remove that dry air from its center within the next day and continue to intensify in increasingly favorable environments. On the Atlantic SST map, I labelled three major time periods that need to be discussed in more detail.

• TUESDAY: Florence will be a hurricane by this point, and will enter the most favorable environment it's ever been in. Wind shear will be practically nonexistent, SSTs are around 29C, and atmospheric moisture is relatively high. These conditions will last for the next two days as Florence moves west-northwest towards the Carolinas, steered by a strengthening ridge of high pressure to the north. Florence will have been strengthening before Tuesday, but once it reaches this extremely favorable region of the Atlantic, it will likely begin a phase of rapid intensification - something that the NHC says is almost certain to happen. From Tuesday to Thursday, Florence will gain the most intensity and be the most unpredictable. The NHC predicts it getting up to a 145 mph Category 4 hurricane during this time frame, but there is a possibility that Florence could get stronger, maybe a high-end Category 4 with 150-155 mph winds. Because of this, everybody should pay very close attention to Florence at the beginning of the week. Unpredictable and unexpected changes in intensity are a strong possibility.
• THURSDAY: Without a doubt, Florence will be a major hurricane (>111 mph winds) at this time, and the first significant impacts from the storm will start being felt in the southeast coast on this day or a bit earlier. While models are more in agreement with Florence's path today than before, there is uncertainty in where it will be on Thursday. It may end up slightly north or slightly south of the location labelled on the SST map. Regardless of where exactly it will be, people from northern Florida to southern Virginia - mainly North and South Carolina - should begin experiencing stronger winds and storm surge. Florence is expected to be a Category 4 at this point when its right off of the SE coast, but even though it's offshore, do NOT underestimate it. Treat it as if it were making landfall at that time (which may turn out to be the case, depending on how fast it ends up).
• FRIDAY-SUNDAY: Florence will most likely make landfall on Friday (or late Thursday), and it will continue to follow the ridge of high pressure off the coast. Depending on how north Florence makes landfall, it or its remnants can be dragged up into New England and the Mid-Atlantic, meaning the entire eastern seaboard, and a few inland states, should be prepared for potential impacts. I can't go too much into detail because this is too far away to make any reliable and specific assumptions.

TROPICAL STORM ISSAC

Formerly Tropical Depression 9, Issac poses a threat of striking the Lesser Antilles as a hurricane, almost exactly a year after Irma and Maria ravaged the Caribbean. Right now it's still facing some wind shear, partially exposing its center of rotation, but it is in better shape than yesterday. Thunderstorm activity has significantly flared up and more of the circulation is being covered. Below is a comparison of Issac's infrared satellite appearance over an eight hour period. While this is slightly outdated, the storm's convection has not changed much since 22:05z.

There are multiple dates to talk about with this storm due to its uncertain track next week.

• TUESDAY: This is when Issac is expected to reach or approach hurricane intensity. The current shear it's fighting a bit will be just about gone, and SSTs will be slightly warmer than before. There is a chance that Issac may end up going through a phase of rapid intensification at this time, but it's a bit too far out to be certain.
• WEDNESDAY: Issac will be a hurricane this day, either as a Category 1 or possibly a Category 2, depending on how much intensification happened within the previous 24 hours. Here, wind shear will be at its lowest and SSTs will remain around 28 C. If Issac doesn't rapidly intensify on Tuesday, then this is the most likely time that it will, which will unfortunately give the residents of the Lesser Antilles less time to prepare for a stronger cyclone. Therefore, preparations should begin as soon as possible in case this storm becomes stronger than anticipated.
• THURSDAY: Late Wednesday into Thursday will be the most uncertain time for Issac. As of late Saturday, there are three different scenarios that could take place. The first and most likely is that Issac will continue on a due west trajectory, passing through the Lesser Antilles as a slightly weaker hurricane due to some wind shear from the north at this time. During the past two days, some models have suggested that Issac may weaken considerably once in the Caribbean (once again from shear), but it will continue through the sea and maybe reach the Gulf of Mexico or pass over Central America between Friday and the following Monday. We will have to wait a few more days for any sort of confidence in Issac's post-Lesser Antilles future. The second scenario is the most concerning: a high pressure system will cause the storm to come up slightly north, bringing it on a path towards Dominica, Barbuda, and/or Puerto Rico. These were by far the hardest hit islands from last year's cataclysmic storms, so any tropical cyclone will be a major threat to their recovery. Finally, the third scenario would have that high pressure system pulling Issac to the north, sparing the Lesser Antilles from a direct hit. So far the latter is the most unlikely - it's been getting less and less probable over the last 24 hours - and there's about an even chance for scenarios one or two happening. I'd say we should be keeping as much of an eye on Issac as Florence.

TROPICAL STORM HELENE

The last storm I will be covering is Helene, which has wasted no time getting its act together. Despite being barely a day old, Helene has been organizing quite rapidly, developing a strong circulation and an organized mass of powerful convection. Right now it doesn't have a well-developed core, but this is going to change very quickly. A comparison of two IR satellite images is below:

In just 7 hours, Helene's organization and convective structure has significantly improved, and it continues to do so. The last image is quite outdated now, as a symmetric mass of powerful thunderstorms (cloud top temperatures of -70 to -80 Celsius) has formed around the center of circulation. It looks like Helene will have a developed core within the next six hours and will reach hurricane status around the same time or not long after. As with the previous storms, I'll go through some important dates for this one.

• MONDAY: Helene will almost certainly be a hurricane by this point. This is when the threat to Cabo Verde will be the greatest. Along with the potential for hurricane force winds, there will be more flooding and heavy rainfall. Already, some of the southern islands have had significant flooding from Helene, resulting in three deaths. This will, unfortunately, not let up through the next day and a half to two days. In addition, there is a good possibility of Helene undergoing a period of rapid intensification by this time frame.
• TUESDAY: This is when Cabo Verde will finally get a break as Helene moves too far from the islands to have any more negative impacts. It will also be the time when the storm will likely max out its intensity. Helene is in an area of 27 C waters, which aren't as favorable as the SSTs Florence and Issac will be in on the same day. Once the cyclone gets into 25 C waters on Tuesday, it will not strengthen any more, or at least not by much. Any intensification process continuing from the previous day may still continue for a little bit, but I think it's safe to say that Helene will be done intensifying at this time...temporarily.
• THURSDAY: There are two tracks Helene could take. The first is a gentle curve to the north, and the second is a much sharper curve. With the latter, there is a potential that Helene will be steered towards the Azores islands, which very rarely gets hit by a full-fledged tropical cyclone (2016 and 2017 were exceptions). Regardless of the exact track, Helene will be moving into more favorable SSTs of 27-28 C that may allow for some re-intensification before other factors take their toll on the storm.

 

Those are my predictions for the three systems in the Atlantic. I meant to have this out an hour and a half ago, but my computer decided it was an excellent time to restart and update. Thank goodness that the KSP Forums save the post you're working on.

[SaturnianBlue]

@ProtoJeb21 Great work! I don't think I can write in much detail, but I will try:

PACIFIC CYCLONES

Note the cold wake left by Super Typhoon Jebi.

POST-TROPICAL CYCLONE NORMAN

After an 11 day trek that involved three rounds of rapid intensification into a major hurricane followed by weakening, Norman has finally abated—under cooler SSTs and high wind shear, the storm's convection has been ripped away from the center of circulation, and the storm is down to winds of 50 mph. With the storm heading north and thus directly away from Hawaii, there is no threat to land.

HURRICANE OLIVIA

Hurricane Olivia is no longer the powerful annular hurricane it was a few days ago, but it is still a hurricane—albeit appearing quite like a blob—with 80 mph winds, though it will continue to weaken once it moves into an area of high wind shear. However, the storm 's threat to land is yet to come, approaching Hawaii relatively quickly (especially when compared to Lane) as a tropical storm from the ENE. The NHC/CPHC has been predicting this consistently, though the forecast models disagree on where the landfall will happen. For example, the GFS predicts the south of the Big Island, the HWRF the north, while the ECMWF predicts Maui.

TROPICAL DEPRESSION EIGHTEEN-E

Once again, a tropical cyclone has formed in the East Pacific, but this storm (to be named Paul) seems to be fairly mild compared to the storms that came before it. The storm is expected to move towards the northwest and then turn more westwards, encountering increasingly cooler temperatures along the way. For now, the NHC does not even predict the storm to reach hurricane intensity, though the EPAC has consistently shown off unexpected rapid intensification. The ECMWF and GFS predict it as being a relatively weak tropical storm, and the HWRF (generally seen as an  intensity model) sees it as a minimal hurricane.

TYPHOON MANGKHUT

Last but certainly not least, Typhoon Mangkhut is still a very formidable threat to the Marianas and beyond. The rapidly strengthening storm is passing through an area of low wind shear and very high SSTs of 29 Celsius. Speeding along at 20 knots (23 mph), the storm track has shifted to place Rota at the center of the cone—a bit north from earlier, which had placed Guam at the center. The storm is expected to pass through as the equivalent of a category 4 hurricane, and subsequently intensify into a super typhoon. After that, the GFS forecasts an impact on the southern half of Taiwan as a sub-900 mb storm, which is probably far too much. Subsequently, the GFS forecast takes Mangkhut into China. The ECMWF takes the storm just north of the Philippines and makes landfall in China north of Hainan, approaching as a very powerful typhoon. Keep in mind that such model runs are over a week in the future and very much subject to change.

 

[ProtoJeb21]

7 hours ago, SaturnianBlue said:

After that, the GFS forecasts an impact on the southern half of Taiwan as a sub-900 mb storm, which is probably far too much.

I don’t think the GFS is too inaccurate with Mangkhut. From the looks of things, it may end up being similar to typhoons like Meranti and Nepartek from 2016, which both reached a minimum pressure of 900 mbar or below on a path towards Taiwan. Every nation after the Marianas should prepare for the worst, just in case. Mangkhut likely won’t end up as strong as the GFS says it will — even in such favorable conditions, a sub-880 mbar Super Typhoon is quite rare and unlikely to happen. 

[ProtoJeb21]

Tropical Tidbits reports that Florence is once again a hurricane, with 75 mph winds as of now. An eye is visibly forming on both visible and infrared satellite imagery now that the system’s convection is much better organized and potent than last night. A Hurricane Hunters flight is heading out to analyze Florence, but it probably won’t arrive for another hour. 

[ProtoJeb21]

@SaturnianBlue the recon aircraft has entered Hurricane Florence and is making its first pass through the center. Meanwhile, Florence’s appearance on satellite imagery is becoming very concerning due to its strong organization and potent convection. A phase of rapid intensification looks to be mere hours away. 

[XB-70A]

Some capture from GOES 16 (which should celebrate its second year of service soon)

Taken between 2018-09-08 11:45:32 and 2018-09-09 17:15:31.

[ProtoJeb21]

The Hurricane Hunters mission has finished and a stronger Category 1 hurricane, with 70 knot (80 mph) winds and a central pressure down to 978 mbar. For comparison, when the mission started a few hours ago, the pressure was at 985 mbar. That’s a 7 mbar drop in central pressure, indicating that Florence is at the beginning of a rapid intensification phase. 

[ProtoJeb21]

Hurricane Florence is undergoing rapid or possibly even explosive intensification. In just twelve hours, its winds have gone up from 85 mph to 115 mph, and they may already be higher. A Hurricane Hunters craft has just entered the center of the storm and briefly found flight-level winds of 130 mph in the first half of the eyewall. The pressure has almost dropped to below 960-955 mbar. Based on this and Florence’s satellite imagery, it will likely become a Category 4 within the next few hours, and there remains a possibility of it nearing or reaching Category 5 intensity by Wednesday before land interaction and drier air halts intensification. 

UPDATE: the HH craft completed its first pass, and the results are extremely concerning. Winds are up to 130-140 mph and the pressure has dropped from 962 mbar to 945 mbar. 

Edited September 10, 2018 by ProtoJeb21

[ProtoJeb21]

@SaturnianBlue Florence’s intensification is....extremely worrying. It’s now a 140 mph Category 4 with a pressure down to 940 mbar. During the last NHC advisory, it was predicted to be a 130 mph storm by this time. If Florence keeps intensifying at this rate, it has a chance of becoming a Category 5 before landfall — something that a few models are predicting. 

[ProtoJeb21]

Several interesting things are starting to happen to Hurricane Florence. 

1.) Microwave satellite data indicates that Florence has yet to develop a complete eyewall.

2.) A second incomplete eyewall appears to be forming. Signs of it can be seen on shortwave and IR imagery. 

3.) After rapidly deepening earlier today, Florence’s central pressure has stated consistent around 939-942 mbar. 

4.) The eye of Hurricane Florence has been slightly shrinking over the past several hours. 

5.) Florence’s convective stricture is starting to change. Some of the outer bands are becoming less potent as more powerful thunderstorms form a well-defined, large, almost perfectly symmetrical circle around the core. 

Based on all these events, there are two possible outcomes for the next 12-18 hours. The first is that Florence will undergo an eyewall replacement cycle before rapidly intensifying again, potentially reaching Category 5 status. The second outcome is that Florence won’t go through an EWRC, but will still be able to improve the structure of its core and convection. Both scenarios will cause a temporary (12-ish hours) halt in intensification before Florence begins another phase of rapid strengthening either during the second half of Tuesday or during Wednesday. In both scenarios, a Category 5 remains a disturbing possibility, but the good news is that drier air and land interaction starting early Thursday will keep this from being a landfalling Cat 5.