Hurricane Marco

[yoda]

Tropical Storm Marco Discussion Number   7
NWS National Hurricane Center Miami FL       AL142020
1100 PM EDT Fri Aug 21 2020

An Air Force Reserve Hurricane Hunter aircraft has investigated the 
system over the northwest Caribbean during the past few hours. The 
plane reported a number of unflagged SFMR winds between 35 and 40 kt 
and max flight level winds of 41 kt. A blend of these data supports 
an intensity of 35 kt, and therefore, this system has been 
designated as Tropical Storm Marco. Deep convection has increased 
near and to the east of Marco's center during the past few hours. 
Although there still isn't much evidence of inner-core banding, the 
data from the plane does indicate that the center of Marco has 
become better defined since the afternoon and that the minimum 
pressure has dropped.

Unfortunately the intensity forecast has not become any clearer and 
confidence in that aspect of the forecast is quite low. Marco is 
embedded within an environment that could support a fast rate of 
strengthening. However, recent microwave data does not indicate that 
the system has developed an inner-core, and only gradual 
strengthening is likely until it does. The intensity guidance spread 
is quite high, with the GFS and ECMWF global models both showing 
little further strengthening, while the HMON regional model rapidly 
makes Marco a hurricane before it reaches the northeast tip of the 
Yucatan peninsula. That possibility can not be ruled out, but a 
majority of the intensity guidance favors the weaker solution of the 
global models. Even with the HMON outlier included, the NHC 
intensity forecast is above the model consensus. Once Marco moves 
over the central Gulf of Mexico, a rapid increase in wind shear 
associated with an upper-level trough should limit the potential for 
further strengthening, and weakening is still anticipated before 
Marco nears the northern Gulf Coast, as shown in the previous 
official forecast.

Confidence in the track forecast is also lower than normal, as the 
models spread remains quite high. Only small adjustments were made 
to the NHC forecast which heavily favors the GFS and ECMWF solutions 
on the left side of the track guidance. It is worth noting that the 
NHC track forecast is near middle of the GFS and ECMWF ensembles. 
Marco is currently forecast to move northwestward toward a weakness 
in the subtropical ridge over the central Gulf of Mexico for the 
next day or two, before the ridge builds and turns the tropical 
cyclone farther west. Near the end of the period, Marco's track and 
intensity could be also influenced by Tropical Storm Laura which is 
also forecast to be over the Gulf of Mexico, however the details of 
that interaction are highly uncertain at this time. Given the high 
uncertainty in the forecast, larger than normal changes could be 
required to future advisories.


Key Messages:

1. Marco is forecast to strengthen over the northwestern Caribbean 
Sea through Saturday as it approaches the northeast coast of the 
Yucatan Peninsula. A Hurricane Watch and a Tropical Storm Warning 
are in effect for portions of that region.

2. The system is expected to move into the south-central Gulf of
Mexico as a tropical storm on Sunday. Although some strengthening
is anticipated on Sunday, weakening is forecast as the system
approaches the northwestern Gulf coast on Tuesday. It is still too
soon to know exactly the location and magnitude of impacts the
system will produce along the central or northwestern Gulf Coast,
and interests in that area should continue monitoring the progress
of this system over the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT  22/0300Z 18.7N  84.9W   35 KT  40 MPH
 12H  22/1200Z 19.7N  85.7W   45 KT  50 MPH
 24H  23/0000Z 21.1N  86.7W   50 KT  60 MPH
 36H  23/1200Z 22.7N  88.0W   55 KT  65 MPH
 48H  24/0000Z 24.4N  89.5W   60 KT  70 MPH
 60H  24/1200Z 25.9N  91.0W   60 KT  70 MPH
 72H  25/0000Z 27.5N  92.8W   60 KT  70 MPH
 96H  26/0000Z 29.0N  95.4W   45 KT  50 MPH...INLAND
120H  27/0000Z 30.0N  97.4W   30 KT  35 MPH...INLAND

$$
Forecaster Zelinsky

[yoda]

[Amped]

Never seen a TC with a 500mb vorticity field like this.

[Jackstraw]

32 minutes ago, Amped said:

Never seen a TC with a 500mb vorticity field like this.

It is a model in the future  and yes it's a bit strange.  The Euro shows something similar but not as vigorous.  My take would be it's a signal of rising air riding the western side of maybe a mid level ridge.  Pretty stale winds off to the east so could induce some vorticity along that line.  200mb winds are from the SW almost on top of that and maybe stretching the latent vorticity NE?  Might be a feature in the models that prevents some big dog strengthening.  I'm sitting in a recliner with my dog watching Shipping Wars, what the hell do I know lol.

[Orangeburgwx]

Marco has a narrow window to get right with an enormous ribbon of shear just to the NW, but it looks like it’s continuing the gradual trend of getting its act together. Recon finding a lower pressure and some stronger winds, especially at FL. Today’s the day for this one to reach its peak intensity given the guidance for the environment ahead.

Yeah, that shear is insane. I wonder why it will not effect Laura the same way it will spread Marco?

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[wizard021]

Just now, Orangeburgwx said:

Yeah, that shear is insane. I wonder why it will not effect Laura the same way it will spread Marco?

Sent from my LML212VL using Tapatalk
 

Marco is clearing the shear for Laura.  Tstms dissolve upper troughs .

[CADEffect]

Should be an interesting approach here. NE to SW center pass. SFMR gusts (rain contaminated) are pretty strong. 

Do you have a twitter account?

-D


.

[wizard021]

Bombing out . 996mb . I was wrong .

[Orangeburgwx]

Should be an interesting approach here. NE to SW center pass. SFMR gusts (rain contaminated) are pretty strong. 

Unflagged 64kt barb

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[Orangeburgwx]

Marco is strengthening. 996.4 extrapolated and unflagged and non rain contaminated SFMR of 48, 49, 51, 52kts. FL max of 69kts.

50kts will put it at 55mph, if he bombs out with a strong outflow wouldn't that trough erode before he gets there?

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[Prospero]

Guess we'll be watching this one more carefully on the Florida Gulf Coast. Couple shifts east and it could surprise a lot of people.

[Hc7]

Saw some talks by Mets of a large Theta-E ridge building in the Gulf in front of where Marco looks to be heading, if Marco can get his timing right and finish reforming the center quickly...it could really explode before getting close to landfall. Things could get realllllly hairy for East Texas/LA, in which case I really hope HWRF continues to be right for Laura and gets the track correct as well with it going into the panhandle/AL predominantly. If not, and the more western tracks from other models verify for Laura...holy hell is LA going to get a gut punch, lets hope that doesnt happen.

[Hc7]

If Marco ends up being stronger than most of the models forecasted(sure seems like it right now), and it goes further east towards landfall, how much will that impact Laura's track? Could Marco then influence Laura into pushing her track/landfall further east as well?

[wizard021]

Just now, Hc7 said:

If Marco ends up being stronger than most of the models forecasted, and it goes further east towards landfall, how much will that impact Laura's track? Could Marco then influence Laura into pushing her track/landfall further east as well?

It will spin up and down.  Too much shear north of it. Tiny storms do that. 

[Kevin Reilly]

6 NM center well with that Marco could rapidly intensify and arguably move further north rather than west towards western Florida Panhandle Mobile in Alabama just east of New Orleans as he follows the jet streak as it lifts NE out of the Gulf of Mexico.  Seems like a steeper climb on the back side of the Atlantic Ridge right now. 

[OSUmetstud]

1 hour ago, wizard021 said:

Marco is clearing the shear for Laura.  Tstms dissolve upper troughs .

The upper level ridge building over Florida and eastern GOM is not caused by a small TC dissolving a strong upper level trough via latent heat...

[hawkeye_wx]

Cuba radar shows the developing eyewall.

Cuba radar

I just got power back after ten days in the dark, following the historic Iowa derecho, so it's nice to be able to follow some tropical action again.

 

[Tallis Rockwell]

All that focus on Laura, while Marco might've always been the real threat.

How bad is the shear? I didn't see much of it yesterday. (Then again the models have been sh!^.)

[TradeWinds]

4 minutes ago, Tallis Rockwell said:

All that focus on Laura, while Marco might've always been the real threat.

How bad is the shear? I didn't see much of it yesterday. (Then again the models have been sh!^.)

Marco's intensification is about to come to a grinding halt. High shear awaits. 

[Tallis Rockwell]

5 minutes ago, TradeWinds said:

Marco's intensification is about to come to a grinding halt. High shear awaits. 

Nasty but how will the shear progress?

[Joseph Torre]

4 minutes ago, TradeWinds said:

Marco's intensification is about to come to a grinding halt. High shear awaits. 

Marco reminds me of Gordon back in 2018. Gordon hit a favorable spot off coast of W Florida. Everyone said, "look its forming into a hurricane and will get even stronger before it makes landfall in AL." Tiny storms spin down as quick as they spin up, and GOM shear hit Gordon and it only made landfall as a TS in AL. High shear awaits Marco, and it will be torn to pieces. As far as Laura is concerned, it will be torn apart over Hispaniola and Cuba, and will have to almost completely regenerate as hits the GOM. Fujiwara probably won't even occur, and one of these weak storms will be consumed by one of the stronger storms. 

[Kevin Reilly]

37 minutes ago, hawkeye_wx said:

Cuba radar shows the developing eyewall.

Cuba radar

I just got power back after ten days in the dark, following the historic Iowa derecho, so it's nice to be able to follow some tropical action again.

 

Way way off course most models drove Marco through Yucatán that’s clearly not happening much further north and east 

[Indystorm]

41 minutes ago, hawkeye_wx said:

Cuba radar shows the developing eyewall.

Cuba radar

I just got power back after ten days in the dark, following the historic Iowa derecho, so it's nice to be able to follow some tropical action again. Storm threading the needle through the Yucatan channel per Cuba radar is not what many models predicted initially.

 

Feel for you.  Was  only out about 4 hours here that evening.  Gonna be a very interesting and perhaps historic time watching the tropics as we move into the coming week.  

[Tallis Rockwell]

Why does NHC think Marco is going to strength further with the shear?

Data from an Air Force Reserve Hurricane Hunter aircraft indicate
that maximum sustained winds have increased to near 50 mph (85 km/h)
with higher gusts.  Additional strengthening is forecast during the
next couple of days as the system approaches the Yucatan peninsula,
and Marco could be near hurricane strength when it moves over the
central Gulf of Mexico Sunday night and early Monday.

Is the shear going to move away from the storm? I was under that impression.

[Kevin Reilly]

1 minute ago, Tallis Rockwell said:

Why does NHC think Marco is going to strength further with the shear?

Data from an Air Force Reserve Hurricane Hunter aircraft indicate
that maximum sustained winds have increased to near 50 mph (85 km/h)
with higher gusts.  Additional strengthening is forecast during the
next couple of days as the system approaches the Yucatan peninsula,
and Marco could be near hurricane strength when it moves over the
central Gulf of Mexico Sunday night and early Monday.

Is the shear going to move away from the storm? I was under that impression.

Also it’s almost cleared the Yucatán it’s well East moving NNW.  It’s practically on the western tip of Cuba.  Guess they should update further? 

[Cheeznado]

That shear is forecast to decrease and retreat north as the UT weakens and retrogrades. The question is where will the storm be at that time- the weaker it gets the more westward it will go and get sheared even more but if it can stay stronger a bit longer it may go on a more northerly path and stay in a lighter shear area. Not saying it will be that big of a deal but it may not totally be "ripped to shreds" either. 

[Joseph Torre]

7 minutes ago, Tallis Rockwell said:

Why does NHC think Marco is going to strength further with the shear?

Data from an Air Force Reserve Hurricane Hunter aircraft indicate
that maximum sustained winds have increased to near 50 mph (85 km/h)
with higher gusts.  Additional strengthening is forecast during the
next couple of days as the system approaches the Yucatan peninsula,
and Marco could be near hurricane strength when it moves over the
central Gulf of Mexico Sunday night and early Monday.

Is the shear going to move away from the storm? I was under that impression.

The shear won't move away, and Marco's small size makes it more susceptible to the negative impacts of shear, so its quite surprising they think it will continue to strengthen

[Indystorm]

NHC says storm is strengthening quickly and forecast to become a hurricane later today per latest update.

[yotaman]

Time to change the thread name to Marco instead of TD14. Who would have guessed that would be on the verge of hurricane status today after the it looked so messy yesterday.

[brentrich]

Well well that escalated quickly.Cat 5 hurricane in brewing?