Hurricane Marco

[TradeWinds]

57 minutes ago, Tallis Rockwell said:

Nasty but how will the shear progress?

Shear is increasing.

[Joseph Torre]

2 minutes ago, WxWatcher007 said:

Still has a 24 hour window per NHC before things become less favorable.

Considering how small Marco is, the shear will tear him to pieces. I would be surprised if it regains hurricane strength, if it even makes it to hurricane strength tonight.

[NavarreDon]

Not the best with models but it looks like the 12Z GFS is initializing with Marco @ 1005. Will this cause issues with the whole run?


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[Jackstraw]

Never underestimate the energy available in 89F degree water 

[Wild Weather Monger]

Huge eastward track shift on 12Z GFS.  Brings it into SE Louisiana. 

[CoastalWx]

Yeah that certainly differs from the NHC track. 

[Windspeed]

6 minutes ago, WxWatcher007 said:

Seems like the globals have been struggling mightily with these two systems. Just leaves a ton of uncertainty on track and intensity.

Globals are a hot mess right now regardless.

[Windspeed]

@Floydbusterupdate the thread.

[Seminole]

21 minutes ago, NavarreDon said:

Not the best with models but it looks like the 12Z GFS is initializing with Marco @ 1005. Will this cause issues with the whole run?


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Louisiana in the cross hairs for both Marco and Laura on that run.  

[wizard021]

Globals can't capture tiny marco well.

[Jackstraw]

6 minutes ago, WxWatcher007 said:

This is a fun track. Watching the environment and in-situ obs with little to no backup.

Too bad both are going to make landfall and people need actual confidence in the forecast.

Like forecasting in the 60's when real men drew the charts lol.  I'm already half way through my case of popcorn.  Lights are flashing, take your seats for Act II 

[CoastalWx]

14 minutes ago, wizard021 said:

Globals can't capture tiny marco well.

Little Marco???

[wxeyeNH]

Just looked at the 12Z GFS.  Possibilities of 2 storms hitting the same area in Louisiana, one after another.  

[Doorman]

OPC 96hr prog....

https://ocean.weather.gov/Atl_tab.php

 

[Jackstraw]

Dew's rising significantly at flt level in that drop.   SHIPS thinks a decent chance at another 25KT over the next 24-36 hours.....

SHIPS Prob RI for 20kt/ 12hr RI threshold=  36% is   7.3 times climatological mean ( 5.0%)
 SHIPS Prob RI for 25kt/ 24hr RI threshold=  66% is   6.0 times climatological mean (10.9%)
 SHIPS Prob RI for 30kt/ 24hr RI threshold=  44% is   6.4 times climatological mean ( 6.9%)
 SHIPS Prob RI for 35kt/ 24hr RI threshold=  33% is   8.4 times climatological mean ( 3.9%)
 SHIPS Prob RI for 40kt/ 24hr RI threshold=  20% is   8.1 times climatological mean ( 2.5%)
 SHIPS Prob RI for 45kt/ 36hr RI threshold=  45% is   9.7 times climatological mean ( 4.6%)
 SHIPS Prob RI for 55kt/ 48hr RI threshold=  35% is   7.6 times climatological mean ( 4.6%)
 SHIPS Prob RI for 65kt/ 72hr RI threshold=  20% is   3.8 times climatological mean ( 5.2%)
    

[Orangeburgwx]

Marco is a 993mb hurricane via latest VDM

Sent from my LML212VL using Tapatalk

[vortex95]

If Macro is a hurricane now, it is still not that impressive on satellite.  Minimal banding and transient convective blow-ups.  It is also elongated N-S.  12z SHIPS output shows significant shear by 18 hr with RH dropping below 60%.  As mentioned in previous posts, it is likely going to get torn apart as it moves further N esp. due to its small size.
http://hurricanes.ral.ucar.edu/realtime/plots/northatlantic/2020/al142020/stext/20082212AL1420_ships.txt
 

[Joseph Torre]

1 minute ago, vortex95 said:

If Macro is hurricane now, it is still not that impressive on satellite.  Minimal banding and transient convective blow-ups.  It is also elongated N-S.  12z SHIPS output shows significant shear by 18 hr with RH dropping below 60%.  As mentioned in previous posts, it is likely going to get torn apart as it moves further N esp. due to its small size.
http://hurricanes.ral.ucar.edu/realtime/plots/northatlantic/2020/al142020/stext/20082212AL1420_ships.txt
 

Yep. Marco is about to meet his demise from the wind shear. It might peak at hurricane strength before shear tears it apart and then it has to start all over again. 

[wizard021]

Further esst track yields parallel shear which is less hostile. 

[lakeeffectkid383]

17 minutes ago, WxWatcher007 said:

No increase in strength at 2pm. I thought that dropsonde did it for sure. It’s not just a gust in one layer, there were hurricane force winds throughout the column. 

Surprised too. Is it just me or does Marco look like he’s moving due north on satellite? This thing keeps landing up further and further east of the forecast track. Could that lessen the impact from shear if it’s further away from the trough or moving more parallel with the trough (northerly) rather than more perpendicular (northwesterly)? 

[Floydbuster]

Marco's intensity will have downstream implications on Laura. A stronger Marco could help erode the ridge slightly in the short term so Laura might pull closer to the Keys.

[NavarreDon]

Tropical Storm Marco Discussion Number 10
NWS National Hurricane Center Miami FL AL142020
400 PM CDT Sat Aug 22 2020

Cutting to the chase, there have been some big changes among the
model guidance, and subsequently the NHC forecast, for Marco this
afternoon. While at this point it's a little speculative, the data
collected by this morning's NOAA G-IV flight in the environment
around Marco and across the Gulf of Mexico may have played a key
role in the significant eastward shift seen in nearly all the 12z
models. This isn't to say that the uncertainty in the eventual
track has diminished. In fact, various ensemble members from some
of the global models still show a potential risk to the coast
anywhere from Texas to Alabama, and it's entirely possible that the
volatile shifts seen in the models could continue. That being
said, the new NHC track forecast has been shifted significantly
eastward and now shows the center of Marco reaching southeastern
Louisiana in about 2 days, which is the scenario currently shown by
the GFS, ECMWF, HCCA, Florida State Superensemble, and the TVCN
multi-model consensus. After Marco reaches the coast, the western
Atlantic ridge is expected to build westward and should cause the
cyclone to move more slowly toward the west-northwest across
southern portions of Louisiana.

As far as the intensity is concerned, the last fix made by this
morning's reconnaissance flight indicated that the pressure had
leveled off, and no higher winds had been observed from what was
measured earlier in the flight. The radar presentation from Cuban
radar has also degraded a bit, so Marco's initial intensity is held
at 55 kt. Marco is beginning to move into a zone of moderate
southwesterly shear, but otherwise favorable conditions of warm
ocean water and some upper-level divergence are expected to foster
strengthening during the next day or so. With the exception of the
HWRF, the other intensity models show Marco reaching hurricane
strength, and the NHC foreast continues to show that possibility
while Marco moves over the central Gulf. The shear is still
expected to strengthen in 36-48 hours when the system is approaching
the northern Gulf Coast, but with the shift in the forecast track,
now there may not be enough time for Marco to weaken below
hurricane intensity before it reaches land. The new NHC intensity
forecast is near or just above the HCCA and Florida State
Superensemble models and holds Marco as a hurricane until it reaches
the coast.

The forecast track changes now bring tropical storm force winds to
the coast in 36-48 hours, which necessitates the issuance of
Hurricane and Storm Surge Watches for a portion of the northern
Gulf Coast. These watches will likely need to be upgraded to
warnings later tonight.

Key Messages:

1. Tropical storm conditions will continue over portions of extreme
western Cuba through this evening. Heavy rainfall is also expected
in the eastern portions of the Mexican states of Quintana Roo and
Yucatan, and across far western Cuba, which could result in flash
flooding.

2. Marco is expected to approach the central Gulf Coast as a
hurricane on Monday. Hurricane conditions, life-threatening storm
surge, and heavy rainfall are possible along portions of the Gulf
Coast beginning on Monday, and Hurricane and Storm Surge watches
have been issued. Interests in these areas should follow any advice
given by local government officials.

3. Tropical Storm Laura could bring additional storm surge,
rainfall, and wind impacts to portions of the U.S. Gulf Coast by
the middle of next week. This could result in a prolonged period of
hazardous weather for areas that could be affected by Marco.
Interests there should monitor the progress of Marco and Laura and
updates to the forecast during the next few days.

FORECAST POSITIONS AND MAX WINDS

INIT 22/2100Z 21.9N 85.7W 55 KT 65 MPH
12H 23/0600Z 23.3N 86.5W 65 KT 75 MPH
24H 23/1800Z 25.3N 87.3W 75 KT 85 MPH
36H 24/0600Z 27.5N 88.3W 75 KT 85 MPH
48H 24/1800Z 29.3N 89.6W 65 KT 75 MPH...ON THE COAST
60H 25/0600Z 30.4N 91.1W 50 KT 60 MPH...INLAND
72H 25/1800Z 31.1N 92.7W 40 KT 45 MPH...INLAND
96H 26/1800Z 32.3N 95.6W 25 KT 30 MPH...INLAND
120H 27/1800Z...DISSIPATED

$$
Forecaster Berg


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[Floydbuster]

 

[Baltimorewx]

13 minutes ago, WxWatcher007 said:

Recon in Marco now and just made its first center pass. 996.5 mb extrapolated. NW to SE. 

So it potentially weakened? Was 992 at 5pm

[Calderon]

Just now, Baltimorewx said:

So it potentially weakened? Was 992 at 5pm

It was just one pass, so it's way too early to say that until we get more fixes. 

[Baltimorewx]

9 minutes ago, Calderon said:

It was just one pass, so it's way too early to say that until we get more fixes. 

Understood but I guess it doesn’t seem like it’s strengthened 

[Calderon]

3 minutes ago, Baltimorewx said:

Understood but I guess it doesn’t seem like it’s strengthened 

Oh, I'm not disagreeing at all when I'm able to look at satellite imagery for Marco versus deployment wx, but for pressure I want to see multiple fixes. We'll see what he's able to do as the diurnal minimum makes it way to that side of the globe. 

[Jackstraw]

I'd like to see them do a drop from 10k on the NW side of the storm before they leave, get a bit of a snapshot of mid to upper level shear velocities/direction.

 

[vortex95]

Problem we are seeing with Macro is similar to Laura, just not quite as bad.  Note how recently convection waned over the center, re-fired in a small blob, and now is waning again.  That's a sign of dry air entertainment.  Also, the larger more intense convective blob just to its NE -- surrounding large blobs like this discrete from the center are not good b/c that area will collapse and send out outflow at low levels into the LLCC.  Also, it interferes with the anticyclonic smooth outflow aloft that tries to get established over the central convection.
 

[Jackstraw]

9 minutes ago, vortex95 said:

Problem we are seeing with Macro is similar to Laura, just not quite as bad.  Note how recently convection waned over the center, re-fired in a small blob, and now is waning again.  That's a sign of dry air entertainment.  Also, the larger more intense convective blob just to its NE -- surrounding large blobs like this discrete from the center are not good b/c that area will collapse and send out outflow at low levels into the LLCC.  Also, it interferes with the anticyclonic smooth outflow aloft that tries to get established over the central convection.
 

Gotcha, thanks for that.  With all of the focus on the shear it's easy to lose focus on some of the other factors.