No change to Nate; Maria fizzles; Katia headed to Britain

By: Dr. Jeff Masters , 3:47 PM GMT en Septiembre 10, 2011

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Tropical Storm Nate in Mexico's Bay of Campeche continues to have trouble intensifying. Latest visible satellite loops show that Nate has a large, cloud-filled center, and the storm is probably pulling in dry air to its north into its center. Nate is also likely having trouble with all the cool waters it has stirred to the surface. Assuming Nate is able to close off its center from the dry air, it would take the storm at least a day to tighten up its rather large center, form a solid eyewall, and reach hurricane intensity. Nate doesn't have enough time before landfall for that to happen, and it is unlikely Nate will ever become a hurricane. The latest wind probability forecast form NHC gives Nate a 13% chance of reaching hurricane strength on Sunday. Latest radar imagery from Alvarado, Mexico shows heavy rains from Nate are affecting the coast near Veracruz, and heavy rains of 4 - 6 inches will be the main threat from Nate.


Figure 1. True-color MODIS image of Tropical Storm Nate taken at 12:45 pm EDT Friday, September 9, 2011. At the time, Nate was a tropical storm with 50 mph winds. Image credit: NASA.

Nate is a small storm, and is not likely to bring significant rains to Texas; only extreme South Texas near Brownsville could see an inch or so of rain on Sunday from an outer spiral band of Nate. Our latest wundermap wind forecast map from the European Center model, with the fire layer turned on, shows that Nate's wind field on Saturday and Sunday will not be large enough to fan the fires burning in Texas.

Tropical Storm Maria
Tropical Storm Maria doesn't look much like a tropical storm--on the latest satellite imagery it looks like a squashed question mark instead of a spiral. The surface circulation center is very poorly defined, and moderate wind shear of 15 - 20 knots has really done the Lesser Antilles Islands a big favor by ripping up Maria. It is doubtful this storm will generate any sustained winds of tropical storm force in the islands, and it is a 50/50 proposition that Maria will degenerate into a tropical disturbance and become ex-Tropical Storm Maria later today. Martinique radar shows heavy rains from Maria are mostly east of the islands, and the thunderstorms are not well-organized into spiral bands. The wind shear affecting Maria will probably last through Sunday. By Monday, wind shear is predicted to fall enough so that Maria could potentially organize again. However, the storm is expected to be far from land when that occurs. Bermuda could see a few rain showers from Maria on Wednesday, and Maria may be a threat to southeast Newfoundland late next week.


Figure 2. Morning satellite image of Tropical Storm Maria shows the the storm looks like a squashed question mark?

Hurricane Katia
Hurricane Katia brushed by Newfoundland, Canada this morning, and is now racing east-northeast at 52 mph into the open Atlantic. With water temperatures 19°C (66°F) underneath it, Katia has lost its tropical characteristics, and has transitioned to a powerful extratropical storm. Extratropical Storm Katia will continue east-northeastward towards Europe, and on Monday, the storm will pass very close to northern British Isles. The offshore waters of Northern Ireland and Western Scotland can expect storm-force winds of 50 - 60 mph on Monday as Katia roars past to the north. The storm will bring 2 - 4 inches of rain to the coast, and likely cause significant tree damage and power failures.


Figure 3. Image of Hurricane Katia taken from the International Space Station at 15 GMT September 9, 2011, by astronaut Ron Garan. At the time, Katia was a Category 1 hurricane with 85 mph winds. Long Island, New York is visible at the lower left.

Elsewhere in the tropics
The NOGAPS and UKMET models predict the possible development of a tropical wave 6 - 7 days from now off the coast of Africa.

I'll have an update by early Sunday afternoon.

Jeff Masters

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Quoting ShenValleyFlyFish:
Good stuff. What are the rain totals so far?
So far, not all that much on land, according to the NESDIS daily 24 hour accumulation (based on satellite rainfall rates). A couple of areas very near the coast have probably had enough.

As of yesterday morning:


And, this morning:


Edit: Bah,, so far, so far, so far I'm trying to multitask...apparently too much.
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789. P451
Quoting atmoaggie:
The 10 meter wind as a metric of comparing one storm to another or for us to compare an experience to a forecast is necessary.

But, given the difficulty in measuring a 10 meter wind amongst waves at sea or given land drag from flora and/or structures is fraught with caveats. It is a truly terrible thing to measure and have much confidence in.

In fact, flight level winds reduced to surface and run in a physical model coupled with a dynamical wave model and/or high resolution surface drag input is probably more realistic than the actual wind obs. (This is tough for me to say. Anyone that knows me knows how much I appreciate in situ obs.)


It is a very difficult thing to do. It's even worse when using instrumentation such as they do.

Which is why I am even more surprised that the NHC, who we had come to know to be quite conservative when setting wind intensities on a storm, have seemingly gone aggressive this year.

That really is the meat of all my bitching the past few weeks.

And, again, NOAA is doing their job. They are sampling, they are accumulating the data, and they are sending it back to the NHC to analyze and interpret.

My problem lies with the NHC's (seemingly to me) aggressive interpretation of the data they are receiving and I feel it's warranted when we have had great difficulty confirming their assessment of a storm's wind speed against a multitude of surface observations.

And it's not even a slight discrepancy. It is large.

The frustrating part is not having an answer to my question, knowing I won't get one, and then the next storm comes along and the same questions just pop up.

Member Since: Diciembre 16, 2007 Posts: 7 Comments: 10202
788. 7544
just got back looks like marias trying to make a nice comeback but is the center west of the islands or east thanks i have to read back and catch up now
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Quoting JLPR2:
haha! XD
Time: 01:44:00Z
Coordinates: 18.8333N 61.3667W
Acft. Static Air Press: 841.6 mb (~ 24.85 inHg)
Acft. Geopotential Hgt: 1,576 meters (~ 5,171 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 141° at 42 knots (From the SE at ~ 48.3 mph)
Air Temp: 13.7°C* (~ 56.7°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 45 knots (~ 51.7 mph)
SFMR Peak (10s) Sfc. Wind: 63 knots* (~ 72.4 mph*)
SFMR Rain Rate: 63 mm/hr* (~ 2.48 in/hr*)
(*) Denotes suspect data

But contaminated, thank God!

LOL Just what we needed.
Member Since: Julio 7, 2010 Posts: 0 Comments: 5725
786. JLPR2
haha! XD
Time: 01:44:00Z
Coordinates: 18.8333N 61.3667W
Acft. Static Air Press: 841.6 mb (~ 24.85 inHg)
Acft. Geopotential Hgt: 1,576 meters (~ 5,171 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 141° at 42 knots (From the SE at ~ 48.3 mph)
Air Temp: 13.7°C* (~ 56.7°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 45 knots (~ 51.7 mph)
SFMR Peak (10s) Sfc. Wind: 63 knots* (~ 72.4 mph*)
SFMR Rain Rate: 63 mm/hr* (~ 2.48 in/hr*)
(*) Denotes suspect data

But contaminated, thank God!
Member Since: Septiembre 4, 2007 Posts: 7 Comments: 8747
Quoting atmoaggie:
The 10 meter wind as a metric of comparing one storm to another or for us to compare an experience to a forecast is necessary.

But, given the difficulty in measuring a 10 meter wind amongst waves at sea or given land drag from flora and/or structures is fraught with caveats. It is a truly terrible thing to measure and have much confidence in.

In fact, flight level winds reduced to surface and run in a physical model coupled with a dynamical wave model and/or high resolution surface drag input is probably more realistic than the actual wind obs. (This is tough for me to say. Anyone that knows me knows how much I appreciate in situ obs.)


I would almost agree. I have never quite trusted SFMR, though I haven't read any papers on it explaining the uncertainties in those measurements. The standard reduction from flight-level has always seemed logical and straight-forward to me.
Member Since: Noviembre 24, 2005 Posts: 635 Comments: 26695
i want more weather from Maria!! :-)
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Squalls approaching the Caguas metro area.
Member Since: Julio 7, 2010 Posts: 0 Comments: 5725
782. DFWjc
Quoting Landfall2004:


If you are talking about that 9-11 photo--then yes--it was disturbing and IMO should not have been shown here, and should never be shown without a warning. It is one of those photo's that affects you down to your core.


Yes it is, cause i had to get the kid out of the room while his father was concerned why i was nearly throwing up... he thought i was sick...i was hoping to never see that photo again...
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781. JLPR2
Quoting CybrTeddy:
SFMR just hit this.
54 knots
(~ 62.1 mph)

53 knots
(~ 60.9 mph)

49 knots
(~ 56.3 mph)

We'll see what the NHC thinks.


Besides those there are many 50-55mph reports. Really interesting.
Member Since: Septiembre 4, 2007 Posts: 7 Comments: 8747
780. P451
Quoting CybrTeddy:
Flight level winds of 55 support a 45-50mph system at this time. There could very well be higher winds, so its quite possible that Maria.. however as ill defined it may be might have strengthened.


It probably has given the persistent convective burst.

I would love to see recon go over a buoy so we could compare reports.

More so I want recon to parallel their initial pass through the system - but do so about 50 miles to the SW of it.

I want to see if we can get a good look at the surface feature or not.

One pass through shows a wind shift but tells us nothing about the overall appearance of the surface feature. Circular, elongated, open... etc.

Member Since: Diciembre 16, 2007 Posts: 7 Comments: 10202
It will be a mistake for the NHC to discontinue all the advisories when there is a rather intensifying storm near the islands.
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Quoting atmoaggie:
Two days of Nate in a radar loop: Link

Landfall loop will be this one: Link
Good stuff. What are the rain totals so far?
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NAEFS mean 8-14 day temperatures = cold in the southeast United States:

Member Since: Noviembre 24, 2005 Posts: 635 Comments: 26695
Quoting DFWjc:
Haven't been on in two days(playing catchup on the posts), and i come back to see, a disturbing picture on this blog. I was able to power off the monitor before my neighbor and his kid walked into the room to chat with me... Is there a policy against that?? Seriously...


If you are talking about that 9-11 photo--then yes--it was disturbing and IMO should not have been shown here, and should never be shown without a warning. It is one of those photo's that affects you down to your core. It is haunting...........
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Quoting ShenValleyFlyFish:
Not "those people" in Mexico?
I'm sure there are some of "those people" everywhere.
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Quoting P451:


Yes, it is. There are instances when a surface wind can be higher than the flight level but it is rare. I've seen it too many times this year with recon. We've seen numerous data blackouts, missions that had to turn around due to difficulties.

I don't trust their SFMR instrumentation. Estimating surface winds isn't a trustworthy science even from such a short distance. Throw a little rain in the mix and you get corrupted echoes for certain.

Watch these systems pass over land and try to match a surface wind estimate with land based observations and you will always shake your head wondering where those higher wind values are.

The 10 meter wind as a metric of comparing one storm to another or for us to compare an experience to a forecast is necessary.

But, given the difficulty in measuring a 10 meter wind amongst waves at sea or given land drag from flora and/or structures is fraught with caveats. It is a truly terrible thing to measure and have much confidence in.

In fact, flight level winds reduced to surface and run in a physical model coupled with a dynamical wave model and/or high resolution surface drag input is probably more realistic than the actual wind obs. (This is tough for me to say. Anyone that knows me knows how much I appreciate in situ obs.)
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773. P451
Quoting ShenValleyFlyFish:


Seems to line up fairly well with buoy stats, no?


Questionable.

Lee's winds were not verified on the surface. Max sustained winds over water were 46kts at the Mars Canyon rig at a height of 122m above the water. On land was 40kt sustained in an early morning rain band at NOLA airport.

Nate's are more difficult because of less stations to go on but lining up what recon estimates were versus what was on those stations and it doesn't even come close. Recon flew right to the coastlines and the highest coastal readings were 20kt while recon estimated 50-60mph surface winds. A rig just SE of Nate went as high as 48kt sustained for some time when he was rated 70mph.

Maria so far, same problem as Nate in regards to number of sites to check, and a buoy is reporting 25kt sustained and recon is getting close to that location while reporting surface winds of 35kt.

We all know the story of Irene's max sustained winds.


Just seems to be some rather large discrepancies.

Member Since: Diciembre 16, 2007 Posts: 7 Comments: 10202
Quoting FrankZapper:
Levi, will you be on Barometer Bob again this year?


This is the first year I have been invited onto the show. I'll be on it during the rest of this season.
Member Since: Noviembre 24, 2005 Posts: 635 Comments: 26695
SFMR just hit this.
54 knots
(~ 62.1 mph)

53 knots
(~ 60.9 mph)

49 knots
(~ 56.3 mph)

We'll see what the NHC thinks.
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Flight level winds of 55 support a 45-50mph system at this time. There could very well be higher winds, so its quite possible that Maria.. however as ill defined it may be might have strengthened.
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Quoting atmoaggie:
Well, you know for whom the NHC graphics are primarily generated for...those people. You know. Those people. Voters and the people driving down the highway while reading a novel.

But, it is generally circular in TS-force winds.

Not "those people" in Mexico?
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Quoting P451:


You didn't waste anyone's time. I obviously have plenty of time to burn this evening as I tie some last moment things together.

The scale itself is the waste of time. I see no value in it's creation or usage whatsoever.



Okay....thanks....glad you have time to burn......that bodes well for me, seeing as I live on the west coast of Florida - about 2 miles from Gulf!!!
Member Since: Agosto 28, 2011 Posts: 0 Comments: 152
766. P451
Going through the blob, finding the higher winds now.

Member Since: Diciembre 16, 2007 Posts: 7 Comments: 10202
Just wondering...

IF Maria impacted and enveloped LA

would you end up with...

MaLAria
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Quoting BahaHurican:


I know Maria is more of a puzzle tonight, but this graphic suggests a good chance of hurricane status for Nate before landfall.... and look how circular the windfield is!
Well, you know for whom the NHC graphics are primarily generated for...those people. You know. Those people. Voters and the people driving down the highway while reading a novel.

But, it is generally circular in TS-force winds.

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763. DFWjc
Haven't been on in two days(playing catchup on the posts), and i come back to see, a disturbing picture on this blog. I was able to power off the monitor before my neighbor and his kid walked into the room to chat with me... Is there a policy against that?? Seriously...
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Maria



Latest AOI[s]
Member Since: Octubre 25, 2005 Posts: 19 Comments: 22682
761. JLPR2
Quoting shellyweathers:
What do yall think about the wave east of the lesser antilles? Any one of you have pictures of it?


Two for one.
Member Since: Septiembre 4, 2007 Posts: 7 Comments: 8747
Quoting Grothar:
Building some cold cloud tops now. Wasn't much there a few hours ago.

Very deep convection.



Nate, notsomuch:
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Quoting P451:


Yes, it is. There are instances when a surface wind can be higher than the flight level but it is rare. I've seen it too many times this year with recon. We've seen numerous data blackouts, missions that had to turn around due to difficulties.

I don't trust their SFMR instrumentation. Estimating surface winds isn't a trustworthy science even from such a short distance. Throw a little rain in the mix and you get corrupted echoes for certain.

Watch these systems pass over land and try to match a surface wind estimate with land based observations and you will always shake your head wondering where those higher wind values are.



Seems to line up fairly well with buoy stats, no?
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014L/XX/M/XX
MARK
19N/61W
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Quoting BahaHurican:
I think he meant the scale was a WoT, not ur question...



Thanks...that's how Levi reponded as well..

hurricanejunky - I tried to open your link, but it required a username/password..

Member Since: Agosto 28, 2011 Posts: 0 Comments: 152
Surface Observation here.

Link
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I know Maria is more of a puzzle tonight, but this graphic suggests a good chance of hurricane status for Nate before landfall.... and look how circular the windfield is!
Member Since: Octubre 25, 2005 Posts: 19 Comments: 22682
Quoting shellyweathers:
What do yall think about the wave east of the lesser antilles? Any one of you have pictures of it?


Member Since: Julio 17, 2009 Posts: 71 Comments: 27074
751. P451
Quoting Sangria:


Thanks for your input....really did not mean to waste anyone's time.......thought this was the best time to ask a "somewhat" off tropical storm question since it was slow in here.


You didn't waste anyone's time. I obviously have plenty of time to burn this evening as I tie some last moment things together.

The scale itself is the waste of time. I see no value in it's creation or usage whatsoever.
Member Since: Diciembre 16, 2007 Posts: 7 Comments: 10202
Two days of Nate in a radar loop: Link

Landfall loop will be this one: Link
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749. P451
Quoting BahaHurican:
I think he meant the scale was a WoT, not ur question...



Yes, exactly, sorry about that if it sounded otherwise.

It's dead in here and the question is not what I was speaking of..

The scale itself which was posted is a waste and of no value whatsoever.
Member Since: Diciembre 16, 2007 Posts: 7 Comments: 10202
XX/AOI/XX
mark
8.0n/28.00w
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747. P451
Quoting JLPR2:
So a question.

Why do the HHs flight level winds seem lower than the surface winds? It's supposed to be the other way around. No?


Yes, it is. There are instances when a surface wind can be higher than the flight level but it is rare. I've seen it too many times this year with recon. We've seen numerous data blackouts, missions that had to turn around due to difficulties.

I don't trust their SFMR instrumentation. Estimating surface winds isn't a trustworthy science even from such a short distance. Throw a little rain in the mix and you get corrupted echoes for certain.

Watch these systems pass over land and try to match a surface wind estimate with land based observations and you will always shake your head wondering where those higher wind values are.

Member Since: Diciembre 16, 2007 Posts: 7 Comments: 10202
Quoting Sangria:


Thanks for your input....really did not mean to waste anyone's time.......thought this was the best time to ask a "somewhat" off tropical storm question since it was slow in here.
I think he meant the scale was a WoT, not ur question...

Member Since: Octubre 25, 2005 Posts: 19 Comments: 22682
In honor of the 51st anniversary of Hurricane Donna, I have put together some of my family's stories and some videos about Hurricane Donna, a storm that will never be forgotten here in Fort Myers, FL and in many other places as well:

CLICK HERE FOR MY HURRICANE DONNA TRIBUTE
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Post 731 it comes from this blog.Need to visit more often.One day a week we have apoloyptic day where we talk about everything that could end the world this week!
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Building some cold cloud tops now. Wasn't much there a few hours ago.

Member Since: Julio 17, 2009 Posts: 71 Comments: 27074
742. P451
Interesting wind directions through the islands.



It hints there is a feature extending southward from Maria.

I hope recon makes a good pass to the south of their first leg as they did earlier this morning - so we can see if it continues to be an elongated feature or not.

They're headed for the big ball of convection right now so we'll get a bead on our max sustained winds soon.



Member Since: Diciembre 16, 2007 Posts: 7 Comments: 10202
Quoting Levi32:


You didn't waste any time. I think all he's doing is expressing his opinion about that particular scale. Your question was great and welcomed. Always feel free to ask.
Levi, will you be on Barometer Bob again this year?
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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