Category Five Hurricane Michael

[WxWatcher007]

Pretty surprised we don't have more talk about this, especially considering that all the major operational guidance has shown some level of development. Still broad and disorganized, but nothing like tracking a good ole Central American Gyre. 

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Fri Oct 5 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical
Storm Leslie, located over the central Atlantic Ocean.

1. Surface observations and satellite data indicate that a broad area
of low pressure is centered near the coast of Honduras. This system
is producing a large area of disturbed weather extending from
Central America east-northeastward across the Western Caribbean to
Hispaniola. Environmental conditions are expected to become more
favorable for development, and a tropical depression will likely
form over the northwestern Caribbean Sea or the southern Gulf of
Mexico by late this weekend or early next week while the system
moves slowly toward the northwest and north.  Regardless of tropical
cyclone formation, this disturbance will continue to bring
torrential rains primarily to portions of Central America, and these
rains should then spread over western Cuba and the Yucatan peninsula
during the next few days.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...high...80 percent.

Forecaster Avila

 

[David Reimer]

Lots of other weather going on right now with crashy the cold front and a fairly substantial precipitation event setting up across the Southern Plains this weekend and early next week. I didn't realize it had even been upgraded to a cherry. I guess the QPF map will be filled with a couple different color-filled maximums over the next week. 

[Windspeed]

ECMWF hints at multiple rounds of Caribbean cyclogenesis in the coming two weeks. First the system that moves into the GOM and then late next weekend another W. Caribbean system.

[ncforecaster89]

I have been aware of this disturbance, myself, but in its current broad and very disorganized state, there's not much to say...without a more defined and consolidated low.  For instance, the possibility exists that the current low being tracked may not be the one that ultimately develops into a TC (i.e. another area of vorticity could spin down to the surface under an area of deep convection within the gyre).  

As such, I have always taken a more conservative approach to TC observation and forecasting than many of my peers, who often times were/are in a rush to be "first"...when patience was/is more prudent. 

Edit: Wanted to clarify that the second paragraph is not, in any way, directed to WxWatcher or anyone else on this board.   

[WxWatcher007]

1 hour ago, ncforecaster89 said:

I have been aware of this disturbance, myself, but in its current broad and very disorganized state, there's not much to say...without a more defined and consolidated low.  For instance, the possibility exists that the current low being tracked may not be the one that ultimately develops into a TC (i.e. another area of vorticity could spin down to the surface under an area of deep convection within the gyre).  

As such, I have always taken a more conservative approach to TC observation and forecasting than many of my peers, who often times were/are in a rush to be "first"...when patience was/is more prudent. 

Edit: Wanted to clarify that the second paragraph is not, in any way, directed to WxWatcher or anyone else on this board.   

Yeah. CAGs are always really interesting to follow to me. Not the highest of ceilings generally, but because of the uncertainty of what may pop you can certainly learn a lot about tropical cyclone genesis.

[yoda]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sat Oct 6 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical
Storm Leslie, located over the central Atlantic Ocean.

1. Recent satellite-derived wind data indicate that an area of low
pressure is centered about 80 miles north of the coast of Honduras,
however, the system is somewhat elongated and does not yet have a
closed circulation.  Heavier showers and thunderstorms have been
developing near and to the east of the low's center during the past
several hours, and extensive cloudiness and showers extend elsewhere
across the western Caribbean Sea eastward over the Greater Antilles.
Environmental conditions are expected to become gradually more
conducive for further development, and a tropical depression is
expected to form over the northwestern Caribbean Sea or the southern
Gulf of Mexico over the weekend or early next week while the system
moves slowly north-northwestward at about 5 mph.  Interests in the
Yucatan peninsula and western Cuba should monitor the progress of
this system during the next several days.  Regardless of tropical
cyclone formation, this disturbance will continue to bring
torrential rains to portions of Central America, the Yucatan
peninsula, and western Cuba into next week.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

Forecaster Berg

[MJO812]

I'm shocked there isn't alot of talk

The models are getting really interesting with this storm.

[TPAwx]

Euro 12z ensembles

 

[WxWatcher007]

NHC will be initiating advisories at 4 PM CDT on Potential Tropical Cyclone Fourteen, located over the northwestern Caribbean Sea.

[Vice-Regent]

Very nice. This could be a potent landfaller. The stars are aligning for such an event. Obviously sympathies go out for those in the affected path. Hopefully it hits a sparsely populated portion of the Gulf Coast.

[WxWatcher007]

Potential Tropical Cyclone Fourteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL142018
400 PM CDT Sat Oct 06 2018

Satellite imagery and surface observations indicate that the
circulation of the low pressure area in the northwestern Caribbean
Sea is getting better defined, and that the associated convection
is becoming better organized.  While the system is currently not
well enough organized to call it a tropical depression, current
indications in the global models and the intensity guidance are that
the system will develop into a tropical cyclone within 24 h and
could bring tropical storm conditions to portions of western Cuba
and the northeastern Yucatan Peninsula.  Based on the need for
warnings and watches in these areas, advisories are being initiated
on Potential Tropical Cyclone Fourteen.

Although the intensity guidance is in excellent agreement that the
system should strengthen through the forecast period, the global
models indicate that shear caused by an upper-level trough over the
Gulf of Mexico will persist through at least 48 h.  In addition, the
strongest winds are currently well removed from the center, which is
likely to slow development.  Based on this, the intensity forecast
is in the lower part of the guidance envelope through 48 h, and then
shows a faster rate of development from 48-96 h when the shear is
forecast to diminish.  The intensity forecast is closest to a blend
of the IVCN and HCCA consensus models.

For the first 24-48 h, the disturbance should move generally
northward on the western side of a weak mid-level ridge over the
Caribbean Sea.  After that time, a large mid-latitude trough over
the central United States and a mid- to upper-level ridge over the
western Atlantic should steer the system generally northward at a
faster forward speed, with the system expected to move near or over
the northern Gulf coast in about 96 h.  After landfall, the system
is likely to recurve northeastward into the westerlies.  The track
guidance is in good overall agreement with this scenario.  However,
it should be noted that there is a nearly 300 n mi cross-track
spread in the guidance at the 96-h point.  The forecast track lies
just to the west of the various consensus models.

Key Messages for Potential Tropical Cyclone Fourteen:

1.  This system is expected to produce heavy rainfall and flash
flooding over portions of Central America, western Cuba, and the
northeastern Yucatan Peninsula of Mexico during the next couple of
days.  The system is also forecast to become a tropical storm by
Sunday night and tropical storm conditions are expected over
portions of western Cuba where a Tropical Storm Warning is in
effect.

2. The system could bring storm surge, rainfall, and wind impacts to
portions of the northern Gulf Coast by mid-week, although it is too
soon to specify the exact location and magnitude of these impacts.
Residents in these areas should monitor the progress of this system.

FORECAST POSITIONS AND MAX WINDS

INIT  06/2100Z 18.0N  86.6W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
 12H  07/0600Z 18.7N  86.7W   25 KT  30 MPH
 24H  07/1800Z 19.9N  86.6W   30 KT  35 MPH...TROPICAL CYCLONE
 36H  08/0600Z 21.0N  86.6W   35 KT  40 MPH
 48H  08/1800Z 22.5N  86.7W   40 KT  45 MPH
 72H  09/1800Z 26.0N  87.5W   55 KT  65 MPH
 96H  10/1800Z 30.5N  86.5W   60 KT  70 MPH
120H  11/1800Z 35.5N  81.5W   30 KT  35 MPH...INLAND

$$
Forecaster Beven

[WxWatcher007]

Gradually getting more organized. Should have a depression soon.

[Hoosier]

HWRF goes a little crazy

 

 

There is a significant model spread in speed, which could be a factor in how strong it is able to get.  The above HWRF is already closing in on the coast Wednesday morning, while the 12z ECMWF was much slower.

[Amped]

00z euro 954mb at 96hrs, looks like it's going between  Panama city and Appalachacola.

[Windspeed]

Noticing a significant strengthening trend on the globals between modeled NE turn and landfall. The 00z ECMWF making Michael a major hurricane got my attention.

 

As several have pointed out including Cowan in his video update last night, the system is fighting upper level shear due to strong westerly flow above 400 mb thanks to an elongated upper trough that stretches into the western Atlantic. This flow is getting pinched off however as a new and advancing strong surface-to-upper trough with cold front moves out of the western CONUS into the GOM. Favorable divergent flow above the 300 mb layer should establish over Michael by tomorrow evening into Tuesday. However, as Michael continues NNW or N in the 700 to 500 mb steering column, 500 to 300 mb SW flow may keep it in check as mid level shear may undercut the mid level circulation and disrupt strong intensfication.

 

What has to be watched closely is how fast the entire steering column and Michael turns into aligned SW flow as this will decrease mid level shear undercutting the cloud canopy and allow better vertical stacking within the cyclone. Simply put, the faster Michael turns NE, the faster significant intensification can occur and the greater the chance for Michael to become a strong hurricane prior to landfall. A nice northerly outflow channel/jet should already have established by this turn and SSTs are still sufficient as Michael will be moving faster than for any significant upwelling to be an issue.

[TPAwx]

7 hours ago, Amped said:

00z euro 954mb at 96hrs, looks like it's going between  Panama city and Appalachacola.

 Intensity up on most of the models, and a larger cluster of Euro members show a NE bend.  

 

[WxWatcher007]

Didn't get into the VWS stuff that you just posted, Windspeed, but totally agree. Posted this in the MA thread. Obviously the post below has a northeast focus. Don't read into it as if I'm calling for a TS from DC to BOS  

3 minutes ago, WxWatcher007 said:

I always perk up more when we talk about Caribbean and homebrew action and here we are. The guidance had been hinting at this potential for weeks, (good job for those of us that pointed it out ) and now it looks like we have a TD that is gradually organizing. 

One thing that is very impressive this morning is the convection. That is a very strong envelope of convection for a TD. We'll see if that persists, but I think thats a signal for a system that should continue to at least gradually intensify despite the current shear. 

The key early question: What's the ceiling?
Usually with something that develops from a Central American Gyre (CAG), the ceiling is pretty low, as systems develop from a sprawling area of disturbed wx and it takes a lot to consolidate into a "pretty" and mature tropical cyclone. However, we've seen some named storms from a CAG evolve into hurricanes, with Nate being a prime example from just a year ago.

It has been interesting to see the guidance bullish on development the past few days, and that continues today with the last few runs of the GFS and the 00z European run looking even more impressive with significant intensification over the next few days.

Let's start by looking at the environment first. 

1. SSTs/TCHP
Both look pretty good (I substituted my usual TCHP plot with the 26 C depth plot because of trouble with the website) and with a decent forward speed and projected track it looks like future Michael will avoid the cold eddies you see below. No real issues here. 

 

2. Wind Shear
Wind shear looks to be one of the potential limiting factors. Right now, the forecast is for the ribbon of shear to the north of future Michael to continue to shift north, leaving light to moderate shear in the path of the system. One thing we have to watch for, just as with Gordon and Florence, is if there is a level of subtly in the upper wind profile that ends up aiding ventilation or hindering the consolidation of a core. As I often say, we need to see a strong inner core before we can get on board with forecasting significant to rapid intensification. The globals right now are bullish on a favorable upper wind profile and the NHC has taken note. We're going to have to watch in real time to see what happens. 

3. Moisture
Just a quick look here. Looking at the latest GFS, there looks to be dry air lurking in the Gulf as the system moves north. We're going to have to watch how that impacts the core and western extent of the rain, as any dry air entrainment will have an impact on development given the small window for intensification. For these kind of systems I definitely want to be on the eastern side unless we're talking about PRE possibilities which would extend heavy rain much further north/west than usual. 

Overall, I think this has a really good chance of becoming a hurricane, and if shear/dry air can be kept at bay, I could see a period of intensification that gets this to a low end category 2. Seeing the guidance so bullish on development is a cause for pause. We'll have a better idea of potential once the HH get in the system to sample the core today and especially tomorrow. 

Overall Track
The steering pattern is pretty simple. The massive high pressure begins to slide east, which steers Michael north. Trough comes from the west and instead of a stall like Florence, this has a much better chance of following climo...movement north to NNE to NE as it picks up speed inland. Obviously, slight differences in timing and speed will determine how far north this gets. I think there's certainly potential to see this further north and inland and rain (less bullish on wind) impacts up the east coast. It's very interesting that the NHC has this moving fast enough to remain a 50mph TS right off the coast of VA. The Euro is slower and much further south, which is also a possibility.  

Definitely something worth watching. This isn't like many of the other systems we've tracked in the past that were unfavored to impact the region from the start. This is how the MA and NE often get remnant action. With the speed of the system, a favorable track and trough interaction could create a more interesting sensible wx impact. 

At any rate, this could be the last hurrah before we leap into the postseason. 

Happy tracking. 

 

[NavarreDon]

14 minutes ago, WxWatcher007 said:

Didn't get into the VWS stuff that you just posted, Windspeed, but totally agree. Posted this in the MA thread. Obviously the post below has a northeast focus. Don't read into it as if I'm calling for a TS from DC to BOS  

  

Thanks for posting. Obviously model error is an issue this early in the game but, they seem to be edging E with a potential landfall. That being said I'm watching closely from Navarre.

[WxWatcher007]

1 minute ago, NavarreDon said:

Thanks for posting. Obviously model error is an issue this early in the game but, they seem to be edging E with a potential landfall. That being said I'm watching closely from Navarre.

Yeah, I feel like there should be a disclaimer every time saying that intensity forecasting is hard, and models are better with track once we have a well defined center. The latest global runs are concerning. Things are still a bit disorganized based on microwave and IR imagery. Although the steering flow looks straightforward, it's always the slight shifts in timing, etc. that impact track and who gets the center. I'd definitely be watching from your spot. 

[WxWatcher007]

Tropical Depression Fourteen Discussion Number   4
NWS National Hurricane Center Miami FL       AL142018
1000 AM CDT Sun Oct 07 2018

Satellite and radar data indicate that the depression continues to
become better organized, but surface data suggests the circulation
may be somewhat elongated.  There is still evidence of westerly
shear as the center is located near the western edge of the main
convective mass, but there has been an increase in banding over
the eastern semicircle since yesterday afternoon.  The depression
appears to be close to tropical storm strength and Dvorak
estimates from TAFB and SAB are between 30-35 kt.  An Air Force
Reserve reconnaissance aircraft is scheduled to investigate the
system early this afternoon and should provide a better assessment
of the intensity of the cyclone.  For now, the intensity is held at
a possibly conservative 30 kt.

The moderate westerly shear that is affecting the depression is
forecast to gradually decrease over the next day or two as an
upper-level trough over the Gulf of Mexico moves westward and
weakens.  This, in combination with warm waters, should allow for
gradual strengthening as the system moves northward over the Gulf of
Mexico.  Nearly all of the intensity models bring the cyclone to
hurricane strength over the Gulf of Mexico in 2 to 3 days, and the
NHC forecast follows suit. The new NHC intensity forecast is
slightly higher than the previous advisory and again lies near the
ICON intensity consensus. This is a little below the more aggressive
HWRF and HCCA models.

The depression is moving northward at about 5 kt.  The system is
forecast to move generally northward during the next 2 to 3 days,
with some increase in forward speed as it moves between a deep-layer
ridge over the western Atlantic and a trough over the west-central
United Sates.  A northeastward turn is expected after 72 hours as
the aforementioned trough progresses eastward across the central
United States.  The dynamical models generally agree on the overall
scenario, but there are still large difference in forward speed. In
fact, the ECMWF ensemble has members that are still over the Gulf of
Mexico in 5 days, and others that reach southern New England in that
time period.  The NHC forecast is near the left side of the guidance
envelope through 48 hours out of respect for the GFS and ECMWF that
are both on that side of the track spread.  After that time, the NHC
track forecast is close to the various consensus aids to account for
both the along and cross track spread of the guidance.


Key Messages for Tropical Depression Fourteen:

1.  The depression is forecast to produce heavy rainfall and
flash flooding over portions of western Cuba and the northeastern
Yucatan Peninsula of Mexico during the next couple of days.

2.  The depression is forecast to become a tropical storm later
today, and tropical storm conditions are expected by tonight over
portions of western Cuba and the northeastern Yucatan Peninsula,
where tropical storm warnings are in effect.

3.  There is an increasing risk of dangerous storm surge, rainfall,
and wind impacts over portions of the northern Gulf Coast by
mid-week, although it is too soon to specify the exact location and
magnitude of these impacts.  Residents in these areas should monitor
the progress of this system.


FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 19.2N  86.9W   30 KT  35 MPH
 12H  08/0000Z 20.0N  86.5W   40 KT  45 MPH
 24H  08/1200Z 21.5N  86.5W   45 KT  50 MPH
 36H  09/0000Z 23.2N  86.8W   55 KT  65 MPH
 48H  09/1200Z 24.9N  87.2W   60 KT  70 MPH
 72H  10/1200Z 28.7N  86.5W   70 KT  80 MPH
 96H  11/1200Z 33.0N  82.5W   45 KT  50 MPH...INLAND
120H  12/1200Z 37.8N  73.0W   45 KT  50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Brown

[TPAwx]

22 minutes ago, NavarreDon said:

Thanks for posting. Obviously model error is an issue this early in the game but, they seem to be edging E with a potential landfall. That being said I'm watching closely from Navarre.

Good luck up there.  

There’s nothing at this time in the steering pattern that raises real concern for Tampa/St Pete, but I have family further north near the Homosassa area.  Nonetheless, I’m doing the gas and Publix runs today.  Should be TS status by the 5 or 11 PM NHC update and that will get the public’s attention all along the coast.

Will be interesting to see how/if this breaks up the red tide around here and south.

[SnowGoose69]

Leaning at the current time towards it being stronger than currently forecast and also probably not hooking as hard at landfall.   I would expect again we will see a delay in the incoming trof or not see it come close at all as the trend has been the last month anytime we see a modeled plains trof making eastward progress.   The landfall point may be close but the system may move more N or NNE after landfall.  The intensity hunch is just what we’ve seen the last few years in the Gulf.  In the absence of any marked shear like a Hermine these things rarely don’t reach at least cat 2 status in there 

[Amped]

GFS is too far east in th short range.  CMC and EURO are further west, and the center  now appears to be close to the Yucatan coast based on visisble imagery.

[WxWatcher007]

Recon en route. 12z GFS still bullish on intensification.

[JakkelWx]

000
WTNT64 KNHC 071653
TCUAT4

Tropical Storm Michael Tropical Cyclone Update
NWS National Hurricane Center Miami FL       AL142018
1155 AM CDT Sun Oct 07 2018

...DEPRESSION STRENGTHENS TO A TROPICAL STORM...

Satellite wind data indicate that the depression has strengthened
into Tropical Storm Michael. The maximum winds are estimated to be
40 mph (65 km/h) with higher gusts. An Air Force Reserve Hurricane
Hunter aircraft is currently en route to investigate Michael.


SUMMARY OF 1155 AM CDT...1655 UTC...INFORMATION
-----------------------------------------------
LOCATION...19.2N 86.9W
ABOUT 90 MI...145 KM S OF COZUMEL MEXICO
ABOUT 225 MI...365 KM SW OF THE WESTERN TIP OF CUBA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES

$$
Forecaster Brown

 

Special update from the NHC

[WxWatcher007]

They could have just waited for recon lol

[Windspeed]

They could have just waited for recon lol

 

True but the data is already there for the upgrade. I think the issue is close proximity to shoreline and strong easterly surface flow already occurring over Cozumel. Needing this named so boating interests there take it seriously.

 

[WxWatcher007]

3 minutes ago, Windspeed said:

 

True but the data is already there for the upgrade. I think the issue is close proximity to shoreline and strong easterly surface flow already occurring over Cozumel. Needing this named so boating interests there take it seriously.

 

Yeah, I was mostly kidding. This has been a long recon flight to Michael. I’m ready to see how organized the inner structure is.

[WxWatcher007]

BULLETIN
Tropical Storm Michael Intermediate Advisory Number 4A
NWS National Hurricane Center Miami FL       AL142018
100 PM CDT Sun Oct 07 2018

...MICHAEL EXPECTED TO SPREAD HEAVY RAINS OVER WESTERN CUBA
LATER TODAY AND TONIGHT...


SUMMARY OF 100 PM CDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...19.2N 86.9W
ABOUT 90 MI...145 KM S OF COZUMEL MEXICO
ABOUT 225 MI...365 KM SW OF THE WESTERN TIP OF CUBA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...STATIONARY
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* The Cuban provinces of Pinar del Rio and the Isle of Youth
* The coast of Mexico from Tulum to Cabo Catoche, including Cozumel

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within 24
hours.

Interests along the northeastern and central U.S. Gulf coast should
monitor the progress of Michael.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 100 PM CDT (1800 UTC), the center of Tropical Storm Michael was
located near latitude 19.2 North, longitude 86.9 West. Michael is
currently stationary but is expected to resume a slow northward
motion later today. A northward motion with some increase in forward
speed is expected over the next few days.  On the forecast track,
the center of Michael will move near the northeastern tip of the
Yucatan Peninsula Monday morning, and then across the eastern Gulf
of Mexico late Monday through Wednesday morning.

Maximum sustained winds are near 40 mph (65 km/h) with higher
gusts.  Strengthening is forecast during the next several days, and
Michael could become a hurricane by Tuesday night or Wednesday.

Tropical-storm-force winds extend outward up to 200 miles (320 km)
mainly to the north and east of the center.

The estimated minimum central pressure is 1004 mb (29.65 inches).


HAZARDS AFFECTING LAND
----------------------
WIND:  Tropical storm conditions are expected to first reach the
coast within the warning area by this evening or tonight, making
outside preparations difficult or dangerous.

RAINFALL:  Total rain accumulations of 3 to 7 inches are expected
over western Cuba and 2 to 4 inches over the Yucatan Peninsula,
Belize, and northern Honduras through Tuesday.  Isolated maximum
amounts of 12 inches are possible in western Cuba.  This rainfall
could lead to life-threatening flash floods and mudslides in areas
of mountainous terrain.

Elsewhere, outer rain bands from Michael are expected to produce
total rain accumulations of 2 to 4 inches across the Florida Keys
through Monday.


NEXT ADVISORY
-------------
Next complete advisory at 400 PM CDT.

$$
Forecaster Brown

[Amped]

Euro is way east at 72hrs,  so is the UKMET.