ATL: MATTHEW - Post-Tropical - Discussion

[Yellow Evan]

LLC is well southwest of the convection, and the chart shows the actual winds, not relative to movement. CIMSS analyzes 20-25kts of storm-relative shear from the southwest at the moment.

Always better to look at satellite. The case for 20-25kt southwesterly shear can't be made when outflow is expanding to the west. The CIMSS map inaccurately analyzes the anticyclone over the coast of South America, when outflow expanding in all directions from the center suggests it's co-located.

Satellite cannot always show relative shear, and it is certainly there as indicated by the last VDM being to the southwest of the convective ball, outside of it in fact.

If outflow is expanding, shear isn't preventing the storm for strengthening though.

[SapphireSea]

Chief Meteorologist Craig Setzer of WFOR TV Miami says that Matthew's future track is uncertain. That 90 degree turn depicted by some models looks highly suspicious to me.

That sharp turn has been puzzling me all along too. Maybe its a numerical (as opposed to a dynamical) model response to something it sees--or a bad response to something it cannot handle.

Dynamic models are seeing collapsing steering layer for the storm and then trying to resolve a movement due to weaknesses to the north then NE as the features progress. A mild ridge may form in the SE US and will have to compete with steering from the stronger Azores Bermuda High. Rule of thumb is that the slow speed would likely invite the next wave of energy to eject it out. Unfortunately this will mean extended time over Bahamas.

[Yellow Evan]

Also can someone tell me why the NHC isn't even forecasting intensification at the climatological rate of 1.0T number per day with near ideal conditions, especially after 48 hours?

[cycloneye]

Also can someone tell me why the NHC isn't even forecasting intensification at the climatological rate of 1.0T number per day with near ideal conditions, especially after 48 hours?

From discussion:

Matthew is forecast to move over warm waters and relatively low
shear during the next few days, and these conditions should lead to
gradual strengthening. There is a possibility, however, that
Matthew encounters some westerly shear in the central Caribbean well
south of Haiti in a day or two. This is an area climatologically
unfavorable for storms to intensify, and Matthew could reduce its
rate of strengthening there. After that, most of the models show a
more conducive upper-level environment, and Matthew could intensify
at a faster rate. The NHC forecast is not very different from its
predecessor and follows closely the intensity consensus

[1900hurricane]

Also can someone tell me why the NHC isn't even forecasting intensification at the climatological rate of 1.0T number per day with near ideal conditions, especially after 48 hours?

They seem to think Matthew will be hampered in the next 48 hours.

Matthew is forecast to move over warm waters and relatively low
shear during the next few days, and these conditions should lead to
gradual strengthening. There is a possibility, however, that
Matthew encounters some westerly shear in the central Caribbean well
south of Haiti in a day or two. This is an area climatologically
unfavorable for storms to intensify, and Matthew could reduce its
rate of strengthening there. After that, most of the models show a
more conducive upper-level environment, and Matthew could intensify
at a faster rate. The NHC forecast is not very different from its
predecessor and follows closely the intensity consensus.

[Hammy]

Always better to look at satellite. The case for 20-25kt southwesterly shear can't be made when outflow is expanding to the west. The CIMSS map inaccurately analyzes the anticyclone over the coast of South America, when outflow expanding in all directions from the center suggests it's co-located.

Satellite cannot always show relative shear, and it is certainly there as indicated by the last VDM being to the southwest of the convective ball, outside of it in fact.

If outflow is expanding, shear isn't preventing the storm for strengthening though.

Outflow isn't expanding over the LLC, but over the MLC, which is to the northeast--the center is very near the edge of the cloud canopy on the last recon pass. And this shear is why NHC is expecting the storm not to intensify much over the next few days.

[Yellow Evan]

Yet they show more intensification from now till 48 hours than after 48 hours when conditions are more favorable.

[Alyono]

Also can someone tell me why the NHC isn't even forecasting intensification at the climatological rate of 1.0T number per day with near ideal conditions, especially after 48 hours?

They seem to think Matthew will be hampered in the next 48 hours.

Matthew is forecast to move over warm waters and relatively low
shear during the next few days, and these conditions should lead to
gradual strengthening. There is a possibility, however, that
Matthew encounters some westerly shear in the central Caribbean well
south of Haiti in a day or two. This is an area climatologically
unfavorable for storms to intensify, and Matthew could reduce its
rate of strengthening there. After that, most of the models show a
more conducive upper-level environment, and Matthew could intensify
at a faster rate. The NHC forecast is not very different from its
predecessor and follows closely the intensity consensus.

Also, they do not give much weight to dynamical models. They prefer SHIPS and the LGEM statistical models

[txwatcher91]

Satellite cannot always show relative shear, and it is certainly there as indicated by the last VDM being to the southwest of the convective ball, outside of it in fact.

If outflow is expanding, shear isn't preventing the storm for strengthening though.

Outflow isn't expanding over the LLC, but over the MLC, which is to the northeast--the center is very near the edge of the cloud canopy on the last recon pass. And this shear is why NHC is expecting the storm not to intensify much over the next few days.

With the current convective burst going on the MLC and LLC will probably continue to stack overnight. Its organizing nicely, has great outflow and will soon have the LLC under convection. Then watch out.

[bahamaswx]

Very symmetric on IR now. An impressive CDO has formed.

[Aric Dunn]

well wsw is the opposite of what all the models are doing.. thats interesting.

[Yellow Evan]

Also can someone tell me why the NHC isn't even forecasting intensification at the climatological rate of 1.0T number per day with near ideal conditions, especially after 48 hours?

They seem to think Matthew will be hampered in the next 48 hours.

Matthew is forecast to move over warm waters and relatively low
shear during the next few days, and these conditions should lead to
gradual strengthening. There is a possibility, however, that
Matthew encounters some westerly shear in the central Caribbean well
south of Haiti in a day or two. This is an area climatologically
unfavorable for storms to intensify, and Matthew could reduce its
rate of strengthening there. After that, most of the models show a
more conducive upper-level environment, and Matthew could intensify
at a faster rate. The NHC forecast is not very different from its
predecessor and follows closely the intensity consensus.

Also, they do not give much weight to dynamical models. They prefer SHIPS and the LGEM statistical models

Which has issues at higher level intensities (look at Lester for instance when they showed weakening too fast due to input not properly showing the affects of SST's)

Code: Select all

 SST POTENTIAL          1.   3.   5.   6.   9.  11.  12.  12.  13.  13.  13.  13.

By comparison, 97E:

Code: Select all

  SST POTENTIAL         -1.  -1.  -1.   0.   6.  14.  22.  27.  30.  32.  32.  30.

[Aric Dunn]

not one model drops it below 14n till after 70 W. its already well below that. that should have a decent impact if it continues this motion for too long.

well not that far below it. but its the wrong direction according the models..

[Aric Dunn]

I think we might need an upper air recon mission soon to help with the ridging.

[Aric Dunn]

with this current motion ( especially if it continues) will likely continue the shift west in the models. if you look each model run has been adjusting the initialization at a faster pace do to it forward progress. the animation tell the story. especially the last 10 or 15 images. clearly the models are having a bit of a hard time with it.

http://flhurricane.com/modelanimator.ph ... 6&title=14

[pcolaman]

with this current motion ( especially if it continues will likely continue the shift west in the models. if you look each model run has been adjusting the initialization at a faster pace do to it forward progress. the animation tell the story. especially the last 10 or 15 images. clearly the models are having a bit of a hard time with it.

http://flhurricane.com/modelanimator.ph ... 6&title=14

I agree. We haven't seen the worst of it yet. Wait till it shows coming up to the north toward the spine or west coast of Florida. Gonna be huge !!

[Hurricaneman]

According to recon this is heading south of due west, its starting to dip possibly sooner than the models indicate

[wxmann_91]

According to recon this is heading south of due west, its starting to dip possibly sooner than the models indicate

The center's is probably going to rock around back and forth a little while an inner core tries to organize. Mean motion averaged over several hours will be more important.

[cycloneye]

I think we might need an upper air recon mission soon to help with the ridging.

Gonzo will fly on Thursday afternoon.

[Aric Dunn]

pressure is going to be below 1000mb this pass pressure already 1003 mb with 43 kt winds.. 998 seems reasonable.