ATL: MATTHEW - Post-Tropical - Discussion

[USTropics]

First visible image of the day

[GCANE]

Looks like its about ready to ramp up but shear is increasing ahead of this.
It is also very wide which would make it slow to ramp up.
IMHO, it won't get past a TD or TS at best until the mid Carib, especially if this hugs the South American coast.
Looking at 06Z GFS 355K PV, upper-level conditions only become conducive for more rapid intensification when it gets to about 65W.
At this time an ULL will be situated at about 21N 41W.
This ULL will quickly move west and come much closer to 97L.
By the time 97L gets to 72W, the ULL is forecast to be at 25N 52W.
Of course, this will create a poleward outflow channel for 97L and aid greatly in its intensification.
At that time, the so called cutoff low that will effect the track of 97L is forecast to be sitting over Lake Erie.
The Cutoff Low's PV anomaly (aka front / trough), which creates the sharp right turn, extends to about Cuba.
This is a bit higher in latitude than the previous model runs.
So, if 97L slows down a bit, tracks a little bit farther south, or doesn't spin up as fast as forecast, it could feel less of the interaction of the Cutoff Low's PV and make the turn later in the West Carib.
IMHO, at this point, this is the likely scenario.

[GCANE]

Not seeing any convection that is high rain rate that would heat up the core.
The only cold-top convection currently firing is well away from the estimated CoC to the NE.

[tolakram]

Why is a cat 3-4 over these very high heat content waters in a low shear environment with a favorable MJO and Kelvin wave unrealistic?

Is this reality yet or still just modeled?

[Nimbus]

The convection is increasing but there is no CDO bursting yet.
The models are still just guessing at the track beyond 70 degrees west with the GFDL suggesting a track into the gulf is still possible.
A slow moving storm in the Caribbean can be a dangerous situation, I keep getting flashbacks of Mitch.
That monster was impossible to model and did every point of the compass before landfall..

[SouthDadeFish]

If there is a closed low-level center, it appears to have reformed a little bit farther east, closer toward the eastern area of convection. This may have slight implications in regard to the phasing of the disturbance and the upper-level trough, potentially allowing slightly less shear. Keep in mind not all trough interactions are negative. If the shear can stay within a favorable range, the trough can provide mechanisms for intensification such as increased outflow channels, which act to increase upper-level divergence, as well as providing a source for increased angular momentum, which also acts to spin up the TC.

[Medtronic15]

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT TUE SEP 27 2016

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

1. Showers and thunderstorms continue in association with a
well-organized tropical wave located about 475 miles east-southeast
of Barbados. However, the low appears to lack a closed circulation
at this time. Environmental conditions are favorable for continued
development, and a tropical depression or tropical storm could form
later today or tonight while the system moves westward to west-
northwestward at 15 to 20 mph. Interests in the eastern and central
Caribbean Sea, including the northern coast of South America, should
monitor the progress of this disturbance, since warnings and watches
could be required at any time. Regardless of whether the system is a
tropical wave or tropical cyclone, heavy rains and wind gusts to
tropical storm force are expected to spread over the Windward
Islands and portions of the southern Lesser Antilles, beginning
tonight and continuing into Wednesday. An Air Force Reserve
reconnaissance aircraft is scheduled to investigate the disturbance
this afternoon.
* Formation chance through 48 hours...high...90 percent
* Formation chance through 5 days...high...90 percent


Forecaster Brown

[abajan]

------------------------------------------------------

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 AM EDT TUE SEP 27 2016

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1045 UTC.

...SPECIAL FEATURES...

An Atlantic Ocean tropical wave is along 51W from 17N southward.
A 1008 mb low pressure center is along the wave near 11N.
Convective precipitation: widely scattered moderate to isolated
strong from 11N to 17N between 48W and 55W. The precipitation
pattern continues to become more organized. It is likely that a
tropical depression or a tropical storm may form later today if
this weather system continues to become more organized. The
forecast movement is to the WNW-to-W about 20 mph. Please
monitor the progress of this weather system if you have any
interests that are in the eastern and central Caribbean Sea,
including the northern coast of South America. Heavy rains and
strong gusty winds, possibly to tropical storm force, are
expected to spread across the Windward Islands and sections of
the southern Lesser Antilles beginning tonight and continuing
into Wednesday. An Air Force Reserve reconnaissance aircraft is
scheduled to investigate the disturbance this afternoon.
The chance of formation during the next 48 hours is high. Gale
wind conditions are forecast in 24 hours, within 120 NM N
semicircle of a 1006 mb low pressure center near 13N57W, and sea
heights are forecast to range from 10 feet to 13 feet. Please
refer to the HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC for more
details. ...

[chris_fit]

I find it interesting that there is no mention of future Matthew (or anything tropical) in any of the NWS Discussions this morning from Tampa, Melbourne, Miami, and Key West.

[Hurricaneman]

I find it interesting that there is no mention of future Matthew (or anything tropical) in any of the NWS Discussions this morning from Tampa, Melbourne, Miami, and Key West.

too many unknowns

[Hypercane_Kyle]

I find it interesting that there is no mention of future Matthew (or anything tropical) in any of the NWS Discussions this morning from Tampa, Melbourne, Miami, and Key West.

There's no real need too. Any FL impacts this storm may bring is over 10 days away per the ECMWF.

[La Sirena]

I find it interesting that there is no mention of future Matthew (or anything tropical) in any of the NWS Discussions this morning from Tampa, Melbourne, Miami, and Key West.

I checked NWS-Key West this morning. They just mention disturbances they're watching. I'm thinking they're just wanting to watch a little more closely before sounding any alarms with such uncertainty in the track.

[Gustywind]

DATE/TIME LAT LON CLASSIFICATION STORM
27/1145 UTC 12.4N 52.0W T1.5/1.5 97L
27/0545 UTC 11.5N 50.6W T1.0/1.0 97L
26/2345 UTC 11.2N 51.1W T1.0/1.0 97L
26/1745 UTC 10.2N 48.3W T1.0/1.0 97L

[USTropics]

Pretty good pass from about 2 hours ago:

[wxman57]

NHC initialized it at 11.3N/52.5W at 12Z, which looks about 1 deg too far south. I certainly think it's at least a depression now. Perhaps an upgrade by 15Z? A potential threat to the East U.S. Coast, but not anytime soon.

[La Sirena]

That's looking pretty impressive. Can't wait to see what recon finds later today.

[CalmBeforeStorm]

Using the first visibles I see the potential center at around 13n and 52w not far from the deep convection to its NE. I think it's a depression already.

[jlauderdal]

I find it interesting that there is no mention of future Matthew (or anything tropical) in any of the NWS Discussions this morning from Tampa, Melbourne, Miami, and Key West.

I checked NWS-Key West this morning. They just mention disturbances they're watching. I'm thinking they're just wanting to watch a little more closely before sounding any alarms with such uncertainty in the track.

its too far out in time to give it much press

[USTropics]

Looks like the NHC will wait until recon:

 https://twitter.com/NHC_Atlantic/status/780738262444961792

[SouthFLTropics]

One important thing to note regarding any potential impacts from 97L to the CONUS is the approach. Angle of attack can mean everything from minor impacts to a direct hit. Impacts from a storm approaching the East Coast from the South or SSE can vary greatly depending on how it approaches the coast. A storm approaching from the East like a typical Cape Verde storm normally would narrows down the point of impact. The best analogy I can give for this is Hurricane Charley. A slight shift right and it was Punta Gorda instead of Tampa. Just something to think about as we look at the longer range models and start to look at potential impacts to Florida and beyond.