PTC Matthew

[HillsdaleMIWeather]

Eye continues to get more and more defined.

[Sophisticated Skeptic]

53 minutes ago, LakeEffectKing said:

This will explode again....I see this getting close to Cat. 5 tonight...

 

 

 

yea, but we only have like 36 hours before land interaction starts occurring.  Matthew seems to be moving slightly faster than expected.  A faster movement would increase the odds of a Florida landfall. 

new NAM shows the faster then expected movement as well.

Quote

Quick question.....someone had been posting that Matthew will strengthen to sub 900mb over the Bahamas. Is this deep strengthening a legit concern, ie, for this system to get that intense? Arent sub 900mb storms extremely extremely rare in that area?

hehe, that was me.  And it's not that rare.   We've just been in a hurricane drought in general the last several years.

[PackGrad05]

What's the odds that the models shift back west to a more NC/SC result?  I could see that happening with faster movement.  

[HillsdaleMIWeather]

I'm asking this to those more seasoned in this sort of thing, if Matthew makes landfall (or close to landfall) in Florida as a Cat 3-4 and then the loop happens and Florida gets affected with it as a major hurricane again, what kind of devastation would we be expecting. 

[beanskip]

12z NAM quite a bit closer to the Fla. coast than the 6z run. 

[WhiteoutWX]

4 minutes ago, Bacon Strips said:

 

 

hehe, that was me.  And it's not that rare.   We've just been in a hurricane drought in general the last several years.

Umm it's extremely rare...there's only been 6 storms in history in the Atlantic sub 900

[ncskywarn]

3 minutes ago, PackGrad05 said:

What's the odds that the models shift back west to a more NC/SC result?  I could see that happening with faster movement.  

Some of the  hi-rez models are hinting at that.

[Sophisticated Skeptic]

1 minute ago, WhiteoutWX said:

Umm it's extremely rare...there's only been 6 storms in history in the Atlantic sub 900

I've seen it several times , maybe i'm just that old.

years go by quick, when ur havin fun.

[superjames1992]

13 minutes ago, Bacon Strips said:

I've seen it several times , maybe i'm just that old.

years go by quick, when ur havin fun.

I believe there were a few such storms in the hurricane-rich 2000s with such low pressures, but it is very rare in general.

https://en.m.wikipedia.org/wiki/List_of_the_most_intense_tropical_cyclones

List of sub-900 mb hurricanes in the Atlantic basin:

Labor Day 1935 (892 mb) - The one that pummeled the FL Keys and destroyed the bridges for the Florida Gulf Coast's Railway's railroad to Key West, which were never rebuilt.

Allen 1980 (899 mb)

Gilbert 1988 (888 mb)

Rita 2005 (895 mb)

Wilma 2005 (882 mb)

[iceicebyebye]

8 minutes ago, HillsdaleMIWeather said:

I'm asking this to those more seasoned in this sort of thing, if Matthew makes landfall (or close to landfall) in Florida as a Cat 3-4 and then the loop happens and Florida gets affected with it as a major hurricane again, what kind of devastation would we be expecting. 

no one is seasoned in that specific scenario

also, bacon bits is a horrid poster, but others should not rule out explosive deepening beyond what appears feasible for a cyclone in this vicinity. If we've seen one thing globally across the major basins with cyclones over the past few years, maximum potential is being redefined

[Derecho!]

7 minutes ago, Bacon Strips said:

I've seen it several times , maybe i'm just that old.

years go by quick, when ur havin fun.

Five, and none of them outside the Caribbean or Gulf with the exception of the Labor Day Keys Storm. 

[LoveSN+]

Please stop using the NAM, or any other models that use NAM initialization. It is useless for tropical cyclones.

[Jim Marusak]

4 minutes ago, iceicebyebye said:

no one is seasoned in that specific scenario

also, bacon bits is a horrid poster, but others should not rule out explosive deepening beyond what appears feasible for a cyclone in this vicinity. If we've seen one thing globally across the major basins with cyclones over the past few years, maximum potential is being redefined

agreed. very few storms pull off that type of broad scale complete looping with a several-hundred mile radius. now are there sometimes a lot of little mini loops within a main path? yes a lot of people have seen that more than a few times. but not many see such a broad scale loop like several models are hinting at.

also agreed on the higher amount of deepening compared to previous years. excessive heat content in areas like the central and western Pacific definitely can help out. in the Caribbean, they were overdue for something like this. but when it comes to large and very strong tropical cyclones in general, one constant thing is that they can be very unpredictable, just because they can "create their own environment". once something breaks that separate environment down, then it becomes more predictable.

[high risk]

6 minutes ago, LoveSN+ said:

Please stop using the NAM, or any other models that use NAM initialization. It is useless for tropical cyclones.

 

    completely true - it has no way to proper initialize the system.    That said, it's hard to ignore that the incoming trough from the west looks much more amplified than other overnight guidance had suggested.

   

[Derecho!]

Definitely hasn't strengthened any on last recon pass...the extrap pressures actually up 2 mb. 

[bobbutts]

25 minutes ago, HillsdaleMIWeather said:

I'm asking this to those more seasoned in this sort of thing, if Matthew makes landfall (or close to landfall) in Florida as a Cat 3-4 and then the loop happens and Florida gets affected with it as a major hurricane again, what kind of devastation would we be expecting. 

It would suck.. Imagine preparing for an impact with poor or unavailable communications, transportation, and compromised structures.

[PackGrad05]

What time do the next big model runs come out?  I'm predicting a swing back the other way based on observed data.

[Cheeznado]

WSI RPM has a glancing hit (eyewall but not the center) hit overnight Thursday near West Palm

[Derecho!]

Just now, PackGrad05 said:

What time do the next big model runs come out?  I'm predicting a swing back the other way based on observed data.

GFS comes out rapidly beginning 1130AM. Then UKMET appears 1230ish. ECMWF much later. 

People really shouldn't bother looking at the Canadian or NOGAPS. 

[NJwx85]

00
WTNT44 KNHC 051454
TCDAT4

HURRICANE MATTHEW DISCUSSION NUMBER  30
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142016
1100 AM EDT WED OCT 05 2016

Both NOAA and Air Force Hurricane Hunter planes have been in the eye
of Matthew during the past several hours.  Data from those planes
indicate that the hurricane is gradually recovering from the
passage over the mountains of eastern Cuba and Haiti. The eye is
becoming better defined on satellite. Based on SFMR winds of
103 kt and a flight-level peak wind of 118 kt, the initial
intensity is 105 kt.

The environment between the Bahamas and Florida is favorable for
Matthew to restrengthen some during the next couple of days.
After that time, the shear is forecast to increase, resulting in
gradual weakening.

[dtk]

1 hour ago, RU848789 said:

I know this question was discussed many pages ago, but figured someone here would know the answer off the top of his/her head: Tropical Tidbits model run data for at least the GFS/CMC shows MSLP way above what the actual/projected MSLP is (e.g., at t=0, both are showing over 990 mbar vs. the actual ~960 mbar); the Euro appears to be correct, though.  Is there some "setting" or selection wherein one can get an accurate pressure?  If not, is the "error" a constant, i.e., can I always subtract about 30 mbar (kind of wondering if during the loop back towards Florida if the storm is at its t=0 pressure of near 960 mbar or really increases to ~990 mbar)?  

And while we're at it, when projecting ahead, often the storm goes outside of the "window" displayed, i.e., east/north of Nova Scotia or south of Cuba, for example - is there a way to shift that window?  Thanks, in advance.  

It depends on what dataset you are looking at.  Most of the stuff that gets distributed and plotted is not direct model output, but instead has been post-processed in some fashion.  Take the GFS model for example, which is a spectral model meaning that the actual model prognostic variables are coefficients for spherical harmonics.  This information gets transformed to a grid (in this case, the native grid is ~13km), whereby additional processing can occur to produce the products that are disseminated.  Sea level pressure is a field that is "reduced" from the surface pressure which obviously shouldn't be an issue over the ocean.  However, it turns out that the post-processor that the GFS uses actually creates multiple MSLP fields, one of which applies a truncation/smoother.  This is a legacy code/option and I don't know the reason for keeping it, but I'm pretty sure that it is still being dumped in the files.  There is a more realistic, non-truncated (unsmoothed) version of the SLP field that is also in the files but I'm not sure if everyone is using this correct version.  On top of that, most users do not use the highest resolution output available which I believe is currently 0.25 degree.  Most folks use the half degree or one degree post-processed output which has additional smoothing/loss of information through the coarsening of the grid.

Bottom line, global models like the GFS do not initialize to the exact minimum pressure value like HWRF/GFDL, but they are much, much closer than some of this coarsened/smoothed output would have you believe.  

Important note:  The GFS actually assimilates the advisory minimum sea level pressure observations from NHC/JTWC as an observation.  This helps perform the amplitude correction to move the initial condition toward, but not all the way to the advisory value.  ECMWF does not perform any special initializations for TCs.  I believe that UKMO does not use the advisory SLP but in a different way than the GFS.  I don't know exactly what the Canadians do.

 

[NJwx85]

I'm really not seeing the increase in shear taking place if the trough remains as flat and progressive as currently modeled. Especially if Matthew were to take a sharper right turn and starts heading back SE.

[Jim Marusak]

13 minutes ago, Derecho! said:

GFS comes out rapidly beginning 1130AM. Then UKMET appears 1230ish. ECMWF much later. 

People really shouldn't bother looking at the Canadian or NOGAPS. 

once a storm has actually formed, the Canadian is not that bad. it's better on path than it is on speed once the storm is in the westerlies. and actually it's pretty good in systems undergoing transformation from tropical to extra-tropical. that being said, don't ever use the Canadian on picking a wave to turn into a tropical cyclone, as it tends to over-develop even the weakest of waves unnecessarily.

[SnowGoose69]

3 minutes ago, NJwx85 said:

I'm really not seeing the increase in shear taking place if the trough remains as flat and progressive as currently modeled. Especially if Matthew were to take a sharper right turn and starts heading back SE.

Storms crossing that area of the Bahamas which are moving N or NW almost never seem to increase much in strength for whatever reason.  This may be a product of the fact most have crossed Hispaniola or Cuba which usually disrupt things more than expected, but I think something else goes on down there too that causes these storms to underachieve somewhat in that area.

[jojo762]

Not sure if anyone has seen or posted this, but Baracoa, Cuba suffered devastating damage. 

 

[Derecho!]

5 minutes ago, Jim Marusak said:

once a storm has actually formed, the Canadian is not that bad. it's better on path than it is on speed once the storm is in the westerlies. and actually it's pretty good in systems undergoing transformation from tropical to extra-tropical. that being said, don't ever use the Canadian on picking a wave to turn into a tropical cyclone, as it tends to over-develop even the weakest of waves unnecessarily.

The NHC verification scores for it are really bad. 

All too often I see it as an outlier giving hope to weenies in the outlier location. Another issue is winter weenies that consider it useful not understanding how poorly it performs in tropics. 

The UKMET/EGRI is vastly, vastly better but because access is far more limited than the CMC it doesn't get discussed enough. 

[NJwx85]

Just now, SnowGoose69 said:

Storms crossing that area of the Bahamas which are moving N or NW almost never seem to increase much in strength for whatever reason.  This may be a product of the fact most have crossed Hispaniola or Cuba which usually disrupt things more than expected, but I think something else goes on down there too that causes these storms to underachieve somewhat in that area.

The forecast for shear to increase isn't until Matthew is somewhere up by Savannah, and I believe contingent on interaction with the trough, which is looking less and less likely.

Matthew at this point is a seasoned vet, having crossed both the mountainous terrain of Haiti and then Cuba, only hours apart. The fact that it has been able to maintain itself as a major hurricane all this time is no short order, and a testament to the strength of the circulation. I would think it's going to take a lot more than a slight increase in shear in a few days to bring Matthew down. Especially since a sharper right turn late in the forecast period would give the TC more time over the gulf stream. 

[Tibet]

Interesting fact.

 

But given CMAS/WEA went operational in 2012 this would make for the first major landfall with the system.... obviously, there is no way to nail down just how this may affected the local populations, without a doubt it will save some lives.

 

Wonder what technological advancements we will start leveraging next to inform the populace.

[Jim Marusak]

3 minutes ago, Derecho! said:

The NHC verification scores for it are really bad. 

All too often I see it as an outlier giving hope to weenies in the outlier location. Another issue is winter weenies that consider it useful not understanding how poorly it performs in tropics. 

The UKMET/EGRI is vastly, vastly better but because access is far more limited than the CMC it doesn't get discussed enough. 

actually, the GEM, especially in the last few years, is quite good in p-type placement within a system for winter weather. its track may not be perfect, but if you want a good snow/ice line, their p-type products are better than most of the US products. but that's something i can go into when it comes to a winter storm. besides, i wonder how much the UK Met Office charges for access for their unified model compared to the ECMWF, which last I checked for their full suite was like 200k per month.

[NJwx85]

GFS is slightly West so far. Looks like the WAR is slightly stronger and the pesky ULL off New England is slightly further East.