Hurricane Katia

[stormspotterlive]

Yet again slightly west on the GFS. so many players here there is a lot That can take this more east or more west. Today's euro should be interesting to see if it shows this set up.

[donsutherland1]

It looks like she skims Nantucket on this run.

The 12z GFS takes Katia by the Mid-Atlantic/New England on a track that is remarkably similar to that of Hurricane #1 (1927), one of the analogs I had mentioned earlier.

http://weather.unisy...927/1/track.gif

ACK and MVY also pick up more than 1" of rain on this run. ACK gets just over 2".

The seeming trend in the evolution of the model cycles is an interesting one. We'll see what the Euro has to show a little later.

[Typhoon Tip]

The 12z GFS takes Katia by the Mid-Atlantic/New England on a track that is remarkably similar to that of Hurricane #1 (1927), one of the analogs I had mentioned earlier.

http://weather.unisy...927/1/track.gif

ACK and MVY also pick up more than 1" of rain on this run. ACK gets just over 2".

The seeming trend in the evolution of the model cycles is an interesting one. We'll see what the Euro has to show a little later.

You know what leaps to mind upon reading that...? That #1 1927 analog could be a 99% fit, and that 1% difference is a strike or no strike on New England

[eurojosh]

You what leaps to mind upon reading that...? That #1 1927 analog could be a 99% fit, and that 1% difference is a strike or no strike on New England

Yes, but isn't there a limitation to the utility of analogs? Just because it looks like 1927, doesn't mean the causality is the same - or was there some odd, stagnant tropical depression in the northern GOM in 1927 as well?

[Typhoon Tip]

Yes, but isn't there a limitation to the utility of analogs? Just because it looks like 1927, doesn't mean the causality is the same - or was there some odd, stagnant tropical depression in the northern GOM in 1927 as well?

Yes, that's the point - right. Analogs are important and we should add, though, because it catalogues for pattern recognition.

[Grothar]

Ridge nosing west a bit more than the 0z but at the same time the remnants of the GOM TS is further along. Losing the weak ridging 87 to 90 hours on the GFS to the NNW of Katia.

I see the ts running up the apps then up to NE with Katia in tow. A long duration rainfall for someone- Susquehanna Valley? Can anyone say Agnes redux here?

[QVectorman]

It isn't just the GFS. The Euro is still not hitting the U.S. even though it it is doing a great job of teasing. I see your point about the UKMET. Perhaps, it will continue to do better for Katia. However, I'm not holding my breath since the UKMET is so far left of the consensus and I believe that it tends to have somewhat of a left bias. With the GFS/Euro still not having a run hitting the U.S. (even though they're getting closer and teasing the weenies), I'm still going with 90% chance of missing the U.S. This is such an atypical pattern for an east coast landfall. Close? Maybe. An actual hit? Very unlikely.

Ugh! I never said it would result in a hit or close call for the US!!!!! I was just pointing out the fact that maybe the UKMET is on to something and there is a chance it may end up being closer to Puerto Rico and 20N at 144 hrs rather than 65W 27N as the GFS forecasts. Which in turn would be a whole new ball game as to where/what it may do beyond 120 hrs.

[GaWx]

Ugh! I never said it would result in a hit or close call for the US!!!!! I was just pointing out the fact that it may end up being closer to Puerto Rico and 20N at 144 hrs rather than 65W 27N as the GFS forecasts

I know you didn't say that about the U.S. I'm also saying that the I think the UKMET has a left bias, which would imply the likelihood that it is not going to be close to 20N at 144 hours since it is an outlier. We'll see what happens.

[Typhoon Tip]

Through 144 hours I have the CMC's best analog 1938 - thoughts? Don, Phil....

[free_man]

Through 144 hours I have the CMC's best analog 1938 - thoughts? Don, Phil....

That's exactly what I said yesterday when the GGEM showed a similar solution.

[isnice]

Through 144 hours I have the CMC's best analog 1938 - thoughts? Don, Phil....

I'm anxious to hear what Don has to say. He seemed to be the only one three days ago that said this could get to 70W.

[QVectorman]

I know you didn't say that about the U.S. I'm also saying that the I think the UKMET has a left bias, which would imply the likelihood that it is not going to be close to 20N at 144 hours since it is an outlier. We'll see what happens.

It could! Hence resulting in its over performance so far haha. Honestly, I never really look at that model. It just caught my interest when looking at the error numbers and decided to investigate it.

[atownwxwatcher]

12 Z CMC @ 144 hrs..

Looks more south then the GFS at the same time

[OSUmetstud]

how can we possibly use 1938 as a synoptic analog when we don't even know the upper air pattern?

The Canadian doesn't look too far different than the GFS at the same time...ridging to the north of the hurricane is weaker...but the storm is located a bit further south and west.

[PSUBlizzicane2007]

A few comments before I have to run off to a Drs. appointment since I've been fairly quiet on Katia lately...

Through 144 hours I have the CMC's best analog 1938 - thoughts? Don, Phil....

Mentioning 1938 as an analog is pretty useless and inflammatory at the moment. Yes, the models have trended west with Katia... but right now it is way too early to be mentioning such a high profile analog. As meteorologists in general, the last thing we need to do at the moment is to drum up the mid Atlantic/northeast only to watch Katia recurve harmlessly out to sea or strike the Atlantic Provinces.

As far as people mentioning the UKMET doing better than the GFS with Katia so far... let's think about why this is happening before we declare the UKMET's long-term solution more viable than the GFS. The UKMET in general has had a significant leftward bias with TC paths this year and in prior years. Katia has remained weaker than the GFS had originally projected due to shear, etc., and due to the fact that it is in the deep tropics... so it has remained left of the projections... this isn't too surprising. If it had been stronger, it would have been more to the right.

When we are looking at the future period when Katia is moving westwards south of the Bermuda High, this is prime time for Katia to strengthen. The stronger Katia gets, the sharper the recurve.... and I highly, highly doubt Katia is going to remain weak at this point unless there is some massive dry air pool that isn't being projected at the moment. There is a reason the GFS and Euro have been more accurate in the long ranges with these recurve scenarios than the UKMET... and that is why we stick to those two models over the UKMET in these situations... particularly since Katia will be out of the deep tropics where the UKMET does better in general. If Katia was a Caribbean tracker, then I'd look at the UKMET more seriously in the longer ranges... but Katia is not.

[donsutherland1]

Through 144 hours I have the CMC's best analog 1938 - thoughts? Don, Phil....

The GGEM is an interesting run. The seeming trend in the models to generally increase the risk of a landfalling storm certainly bears watching. Let's see if the Euro makes its own contribution to the trend a little while from now.

[k***]

does the CMC go beyond 144 hours? just wondering how we can conclude it's 1938 when it's several hundred miles away from NE and we don't have 500mb maps to compare

[ezweather]

You know I'll throw my two cents worth here. Tip can post what he wants. He always has some interesting points he makes. He's just putting some examples out there. Its clear that the models are getting closer to the East Coast with each run. Obviously, we don't want to speaking loudly on a landfall along the East Coast. Totally agree on not getting the public all worked up.. Let's see how the runs go this weekend. Right now, this recurve out to sea solution is still there on the table. But to me, there is a low risk for say a landfall anywhere from the Carolinas up to New England. Thats what I'll put in my hazardous weather outlook forecast I issue on Saturdays.

Anyway, we'll see what happens. Euro out in a few..

[QVectorman]

Yeah, the CMC and UKMET have both performed about the same error numberwise with this storm and their solutions start to diverge drastically at about 60 hrs, UK begins to curve SW and CMC keeps tracking NW so I guess we will know in about 60 hrs, which one has the better solution.

[Typhoon Tip]

does the CMC go beyond 144 hours? just wondering how we can conclude it's 1938 when it's several hundred miles away from NE and we don't have 500mb maps to compare

Most Meteorologist can deduce with above 50% confidence what the mid levels of the atmosphere were doing by analyzing the available surface pressure pattern. You learn that when you get educated for the discipline of the science.

That said, the surface pressure pattern on the morning of the 20th of September 1938 showed the hurricane with and inverted trough extending from it up and down the Easter Seaboard, much like the CMC runs shows at 144.

It is true that we cannot know "exactly" what it was doing immediately preceding and during the 1938 event, the track alone up through 144 hours in this 12z CMC run does bear some resemblance.

[Ellinwood]

You know I'll throw my two cents worth here. Tip can post what he wants.

Katia has Katrina written all over it (hell, just look at the letters in the name! Not a coincidence if you ask me). Just like Irene did. Massive damage to the East Coast.

See what happens when people can post what they want?

Problem is people WERE comparing Irene to Katrina. That's just silly.

[Ellinwood]

Most Meteorologist can deduce with above 50% confidence what the mid levels of the atmosphere were doing by analyzing the available surface pressure pattern. You learn that when you get educated for the discipline of the science.

That said, the surface pressure pattern on the morning of the 20th of September 1938 showed the hurricane with and inverted trough extending from it up and down the Easter Seaboard, much like the CMC runs shows at 144.

It is true that we cannot know "exactly" what it was doing aloft during immediately preceding and during the 1938 event, the track alone up through 144 hours in this 12z CMC run does bear some resemblance.

Yeah, above 50%! That really holds up to the stringent statistical probabilities set forth by scientific standards.

[Mallow]

Most Meteorologist can deduce with above 50% confidence what the mid levels of the atmosphere were doing by analyzing the available surface pressure pattern. You learn that when you get educated for the discipline of the science.

That said, the surface pressure pattern on the morning of the 20th of September 1938 showed the hurricane with and inverted trough extending from it up and down the Easter Seaboard, much like the CMC runs shows at 144.

It is true that we cannot know "exactly" what it was doing aloft during immediately preceding and during the 1938 event, the track alone up through 144 hours in this 12z CMC run does bear some resemblance.

The CMC shows Katia going out to sea:

http://www.meteo.psu.edu/~gadomski/CMC_12z/cmcloop.html

[OSUmetstud]

Most Meteorologist can deduce with above 50% confidence what the mid levels of the atmosphere were doing by analyzing the available surface pressure pattern. You learn that when you get educated for the discipline of the science.

That said, the surface pressure pattern on the morning of the 20th of September 1938 showed the hurricane with and inverted trough extending from it up and down the Easter Seaboard, much like the CMC runs shows at 144.

It is true that we cannot know "exactly" what it was doing aloft during immediately preceding and during the 1938 event, the track alone up through 144 hours in this 12z CMC run does bear some resemblance.

the northern stream was certainly involved in 1938...it wasn't just some weak cut-off in the Tennessee Valley causing a storm to move at 60 mph up the coast. The CMC and the current pattern being modeled in general I can say with some certainty does not resemble 1938...1938 would have had some rediculous 500mb negative anomalies over the Midwest/TV and ridiculous positive anomalies over Nova Scotia/Labrador in order to induce such forward speed. The modeled pattern does not have those. The CMC at 180 hours is well off the coast...looks to be going out to sea.

[atownwxwatcher]

There is a reason that the NHC only goes out to 5 days because anything beyond that is a crapchut and becomes less reliable..

In other words a model could show a landfall in the long range today and 6 hrs later not show it...

The moral of the story is that just because something is "shown" as going OTS or close to the East coast etc does not mean that will be the end result...

No one can say with certainty.. all they can do is make educated guesses!

[Typhoon Tip]

The CMC shows Katia going out to sea:

http://www.meteo.psu...2z/cmcloop.html

Not shocking... But, that's any model trying to dicepher a track beyond D6 , which is likely an error anyway. Up through 144 hours the track on that model run looks intriguing. The inverted trough extending up the EC is also an interesting homage.

[wxsniss]

Most Meteorologist can deduce with above 50% confidence what the mid levels of the atmosphere were doing by analyzing the available surface pressure pattern. You learn that when you get educated for the discipline of the science.

That said, the surface pressure pattern on the morning of the 20th of September 1938 showed the hurricane with and inverted trough extending from it up and down the Easter Seaboard, much like the CMC runs shows at 144.

It is true that we cannot know "exactly" what it was doing immediately preceding and during the 1938 event, the track alone up through 144 hours in this 12z CMC run does bear some resemblance.

Neither hype nor a forecast here.

Just some maps that may add to the discussion. Along with inverted trough, very strong Bermuda high farther north that steered 1938 hurricane farther up the coast.

[chris87]

why don't you go draw the 500 mb map and show it to us? I'm interested to see it...only because I've seen reanalysis for this storm...and I want to see how far off you are with your 50% confident assessment?

I'll give you a clue...don't draw the 144H 500 mb from the CMC...you'd be wrong.

Most Meteorologist can deduce with above 50% confidence what the mid levels of the atmosphere were doing by analyzing the available surface pressure pattern. You learn that when you get educated for the discipline of the science.

That said, the surface pressure pattern on the morning of the 20th of September 1938 showed the hurricane with and inverted trough extending from it up and down the Easter Seaboard, much like the CMC runs shows at 144.

It is true that we cannot know "exactly" what it was doing immediately preceding and during the 1938 event, the track alone up through 144 hours in this 12z CMC run does bear some resemblance.

[HurricaneJosh]

Naming 1938 as an analog for a run-of-the-mill, minimal hurricane way E of the Lesser Antilles is just not reasonable.

The 1938 'cane was a once-a-century event-- if that-- and needs to really be mentioned with a little more care.

[Typhoon Tip]

the northern stream was certainly involved in 1938...it wasn't just some weak cut-off in the Tennessee Valley causing a storm to move at 60 mph up the coast. The CMC and the current pattern being modeled in general I can say with some certainty does not resemble 1938...1938 would have had some rediculous 500mb negative anomalies over the Midwest/TV and ridiculous positive anomalies over Nova Scotia/Labrador in order to induce such forward speed. The modeled pattern does not have those. The CMC at 180 hours is well off the coast...looks to be going out to sea.

Yeah, I was looking at the pressure pattern/evolution up to and during the 1938 event and could see the norther stream involvement (or visualize that rather....).

Whether it is the northern stream trough axis in the OV, or and OV to TV trough that is quasi closed is less important to me. Correct me if I am wrong, both could impart a S --> N point steering field along and off the EC.

That CMC inverted trough signal at D6 - obviously prone to big error but for the sake of discussion - is an interesting homage I think. Also, should a S-->N steering feild evolve and the ridging out around 55W become more robust that all this becomes academic. It would come up to about the mid Bahamas or 70W and shoot N - not out to sea and through that ridge. That's *if* *if* *if*. Call it educated spit-balling, haha.

I remember in the days leading up to Hurricane Gloria ...back before the TWC garnered the rep it currently has, they kept updating with 'the turn to the N never materialized'.

I guess a point I'm dancing around is, although I agree with out to sea idea, I don't see why an EC hit somewhere has to be so preclusive. That's not sound Met reasoning at this stage of the game imo. Just trying to show some alternate possibilities here.