Nate almost a hurricane; Maria remains disorganized

By: Dr. Jeff Masters , 9:05 PM GMT on September 08, 2011

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An Air Force Reserve hurricane hunter aircraft is in Tropical Storm Nate, and has found winds much stronger than the storm's satellite appearance would suggest. At 2:17 pm EDT, the aircraft measured winds at their flight level of 1500 feet of 93 mph, which would ordinarily support upgrading Nate to a Category 1 hurricane. Surface winds measured by the SFMR instrument were about 70 mph, suggesting that Nate is indeed very close to hurricane strength. However, latest visible satellite loops show that if Nate is a hurricane, it's only half of a hurricane. Nate's low-level center is exposed to view, due to northeasterly upper-level winds that are creating a moderate 10 knots of wind shear. This shear is keeping all of Nate's heavy thunderstorms pushed to the south side of the center, and the northern half of the storm almost cloud-free. Sustained winds at Buoy 42055, about 140 miles to the northwest of the center of Nate, were just 28 mph at 3:50 pm EDT this afternoon. Water vapor satellite loops show that there is a large area of very dry air from Texas to the north of Nate, and this dry air is keeping the northern half of the storm dry.

Nate will meander in the Bay of Campeche for several days, and the computer models are sharply divided on what happens early next week to the storm. A ridge of high pressure is expected to build in to the north of the storm, potentially forcing it westwards to a landfall in Mexico. However, our two best-performing models last year, the GFS and ECMWF, predict that a weak trough of low pressure expected to move across the U.S. early next week will be strong enough to turn Nate northwards towards an eventual landfall along the northern Gulf Coast. We will have to wait until the NOAA jet makes its first mission to sample the steering currents in the Gulf of Mexico to get a better idea on how probable this northern path might be; their first flight will be tonight, and the data will make it into the 8 pm models runs that will be available first thing Friday morning. As far as intensity goes, the very dry air to Nate's north should begin being less of a problem for it by Friday, when the upper level winds shift more to blow from the southeast, and the shear drops to the low range, 5 - 10 knots. Since the storm is moving very slowly, it will upwell cooler waters from the depths that will slow intensification, though.


Figure 1. Afternoon satellite image of Nate.

Tropical Storm Maria
Tropical Storm Maria barely survived as a tropical storm today, but is now making a bit of a comeback. Satellite loops show that Maria has been badly ripped up by the 10 - 20 knots of wind shear affecting it. The low-level center has been exposed to view most of the day, and surface arc-shaped clouds have been racing away from the storm to the west this afternoon, indicating that dry air has been getting into Maria's thunderstorms and disrupting the storm. However, the areal coverage and intensity of Maria's thunderstorms have increased a little in the past two hours. Maria is passing close to buoy 41040, which measured sustained winds of 36 mph, gusting to 45 mph, at 2:50 pm EDT.

Wind shear is predicted to fall to the low range on Friday as Maria approaches the Lesser Antilles. In addition, as I noted in this morning's post, Maria will be encountering an atmospheric disturbance known as a Convectively-Coupled Kelvin Wave (CCKW) that is currently passing through the Lesser Antilles Islands. There is a great deal of upward-moving air in the vicinity of a CCKW, and will help strengthen the updrafts in Maria's thunderstorms, potentially intensifying the storm. None of our models are detailed enough to "see" CCKWs", so we may see more intensification of the storm than the models are calling for. I believe Maria will continue to organize and arrive in the Lesser Antilles Islands as a tropical storm with 50 - 60 mph winds. The latest run of the GFDL model predicts that Maria will be a Category 1 hurricane on Saturday afternoon when it moves through the Virgin Islands, and a Category 2 hurricane Sunday night when it moves through the Turks and Caicos Islands. This is on the high end of what is possible, and I think it more likely that Maria will be a tropical storm with 50 - 60 mph winds in the northern Lesser Antilles, 60 - 70 mph winds in the Virgin Islands and Puerto Rico, and a Category 1 hurricane in the Turks and Caicos Islands--assuming passage over Puerto Rico and the eastern tip of the Dominican Republic does not significantly disrupt the storm. A lower intensity, as forecast by NHC, is certainly quite possible, as Maria may continue to struggle with the dry air and wind shear besetting it.

The latest computer model runs have been trending more southwards, and the Northern Lesser Antilles, Virgin Islands, Puerto Rico, the Turks and Caicos Islands, and the Bahama Islands are all at high risk of a direct hit by Maria. The models are split on how strong the steering influence a trough of low pressure along the U.S. East Coast will have once Maria approaches the U.S. East Coast. Most of the models foresee that Maria will turn north before arriving at Florida, and potentially threaten North Carolina, Bermuda, or Canada. The latest run of the GFDL model, though, brings Maria through the Bahamas to a point just 100 miles southeast of Miami as a hurricane on Tuesday afternoon. While this forecast is an outlier, and it is more likely that Maria will turn north before reaching Florida, it will be another two days before we will have a fair degree of confidence on when Maria will curve to the north.

Lee's rains trigger historic flooding in New York and Pennsylvania
An extreme rainfall event unprecedented in recorded history has hit the Binghamton, New York area, where 7.49" of rain fell yesterday. This is the second year in a row Binghamton has recorded a greater than 1-in-100 year rain event; their previous all-time record was set last September, when 4.68" fell on Sep 30 - Oct. 1, 2010. Binghamton has also already broken its record for rainiest year in its history. Records go back to 1890 in the city. The rain has ended in Binghamton, with this morning's rain bringing the city's total rainfall for the 40-hour event to 9.02". The Susquehanna River at Binghamton has risen to 25.69', its highest level since records began in 1847, and is now spilling over the flood walls protecting the city, according to media reports. In Hershey, Pennsylvania, Swatara Creek is 19' over flood stage, and more than 9' above its record flood crest. Widespread flash flooding is occurring across the entire area, and over 120,000 people have been evacuated from their homes.


Figure 2. Seven-day precipitation amounts from Tropical Storm Lee and its remnants. Image credit: NOAA/AHPS.


Figure 3. The Susquehanna River at Binghamton has crested this afternoon at its highest flood height on record, 25.69'. Records at this gauge go back to 1847. Image credit: NOAA/AHPS.


Figure 4. In Hershey, Pennsylvania, Swatara Creek is 19' over flood stage, and more than 9' above its previous record flood crest. The river is forecast to crest at 27.2' (green lines are the predictions.) Records at this gage go back to 1930. Image credit: NOAA/AHPS.

The extreme rains are due the the remains of Tropical Storm Lee interacting with a stationary front draped along the Eastern U.S. Adding to the potent moisture mix last night was a stream of tropical moisture associated with Hurricane Katia that collided with the stationary front. You don't often see a major city break its all-time 24-hour precipitation record by a 60% margin, according to wunderground's weather historian, Christopher C. Burt, and he can't recall ever seeing it happen before. It's worth noting that the Susquehanna River Binghamton stream gage, which has been in operation since 1847, is due to be shut off in 3 weeks due to budget cuts. Here's the note at the USGS web site:

NOTICE (03/23/2011)--Data collection at this streamgage may be discontinued after October 1, 2011 due to funding reductions from partner agencies. Although historic data will remain accessible, no new data will be collected unless one or more new funding partners are found. Users who are willing to contribute funding to continue operation of this streamgage should contact Rob Breault or Ward Freeman of the USGS New York Water Science Center at 518-285-5658 or dc_ny@usgs.gov.

I'll have an update in the morning.

Jeff Masters

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Kati sure did some upwelling
Member Since: Posts: Comments:
Quoting Grothar:



After all, it is a developing model! What did you expect.


touche'
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Not quite yet...still got another 3 weeks or so before things start to quiet down in that region. The recent lack of vigorous AEW's can be attributed to the lack of upward motion over most of the African continent.



The GFS already has upward motion in our octant by the start of next week and all the way into the end of the month.



So maybe another round is left... 2 storms here...
Member Since: Posts: Comments:
Quoting clwstmchasr:


No farting in the shower.



lol how about now can i fart
Member Since: May 21, 2006 Posts: 5091 Comments: 114709
Quoting Swede38:

Texas does.



LOL


can new yourk join the fun
Member Since: May 21, 2006 Posts: 5091 Comments: 114709
1071. BDADUDE
Katia passing by.
Member Since: Posts: Comments:
1070. txjac
Quoting owntime:


I will take it, last night I wished for another Ike, which desroyed a big part of my property but I have no desire to be burned up. Thank goodness for the high $ insurance I bought, I guess.


Almost with you there ..Ike was damaging but we need something to put the fires out and get the ground soaked
Member Since: Posts: Comments:
Quoting luigi18:
Hey Guys do you thing i should be prepare or is just really a tropical Low at the time she come for a pina colada here in San Juan


Maybe You can have that pina in Tambuktu / Sandy Beach in Rincon....
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1067. Swede38
Quoting Tazmanian:
am going too take a shower if any one wants too join me

Texas does.
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1066. Grothar
Quoting Swede38:


Hang in there, we all have to

Cheers


It should get interesting in the next few days.

(Hei, fetter! Er du svenske?)
Member Since: July 17, 2009 Posts: 69 Comments: 25321
1065. BDADUDE
Katia passing by.
Member Since: Posts: Comments:
Quoting sunlinepr:
CV season going down??

Not quite yet...still got another 3 weeks or so before things start to quiet down in that region. The recent lack of vigorous AEW's can be attributed to the lack of upward motion over most of the African continent.



The GFS already has upward motion in our octant by the start of next week and all the way into the end of the month.

Member Since: Posts: Comments:
1063. owntime
Quoting Dakster:
If maria's model keep trending south, it is possible Texas could get relief from her...


I will take it, last night I wished for another Ike, which desroyed a big part of my property but I have no desire to be burned up. Thank goodness for the high $ insurance I bought, I guess.
Member Since: Posts: Comments:
1062. JGreco
Quoting 996tt:
The models are suggesting the development of the pattern I suggested right after Lee cruised by and this strong seasonal changing front dove through so deeply. BOC storms remain in the BOC. GOM basically gets shut down for business and if one makes it through the Keys area, it will hit Northern Mexico or extreme Southern Texas. This is pretty much the pattern every year when we get a deep diving front that drops temperatures 10 to 20 degrees and signifies a change to fall. We usually just get it in October or November.

Looks like our GOM storm activity will be cut short this year. Nate is prime example. Anyone disagree or have any thoughts. Hate to see out season over, but that front seems to spell the end. I know in years past NHC and TWC have commented on changes in the patterns of tropical storm activity following such fronts.


Sorry I have to completely disagree with you. Your going to tell me every other year except this year this type of pattern change typically comes at the butt end of October, not September. No offense...I just don't buy it:)
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Quoting 996tt:


Yeah, I have zero raw or real data. I just bring it up for comments as I can specifically recall NHC and TWC forecasters saying front signifies end of likelihood. We just got it so early this year. Kind of bummed a bit about it because I have to admit, I like small cat 1s. They are kind of fun to ride out. Hate the strong stuff though after losing two houses.


Tell me about it. I was hoping to acquire decent footage from Lee, and he ended up no worse than an afternoon thunderstorm. Oh well lol.
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1060. JLPR2
Quoting luigi18:
Hey Guys do you thing i should be prepare or is just really a tropical Low at the time she come for a pina colada here in San Juan


I'll wait till tomorrow morning to answer that.
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1058. JLPR2
And NE of PR it goes. XD

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1057. luigi18
Hey Guys do you thing i should be prepare or is just really a tropical Low at the time she come for a pina colada here in San Juan
Member Since: September 21, 2008 Posts: 0 Comments: 470
Quoting Grothar:

That really looks like Maria is headed straight for Florida.
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1054. JLPR2
Quoting CaribBoy:
NAM 00Z link please :) ?


Link
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1053. 996tt
Quoting KoritheMan:


There may be some truth to it. While I haven't done any heavy research on it, I have noticed that in years past, anomalous ridging typically follows such fronts. A couple of recent occurrences is Marco in 2008, and Earl of 2010.


Yeah, I have zero raw or real data. I just bring it up for comments as I can specifically recall NHC and TWC forecasters saying front signifies end of likelihood. We just got it so early this year. Curious what experts on here might have as far as data from past and very surprised TWC forecasters aren't commenting on it. Maybe they want to keep people's attention.

Kind of bummed a bit about it because I have to admit, I like small cat 1s. They are kind of fun to ride out. Hate the strong stuff though after losing two houses.
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1052. Grothar
Quoting Some1Has2BtheRookie:


My eyes were playing ticks on me with that post. I went to put on my glasses to see it and then it got HUGE. Maybe I need new glasses?

Post #947



After all, it is a developing model! What did you expect.
Member Since: July 17, 2009 Posts: 69 Comments: 25321
1051. Swede38
Quoting Grothar:


Boy, I really missed you people.


Hang in there, we all have to

Cheers
Member Since: Posts: Comments:
1050. Dakster
Quoting Grothar:


Boy, I really missed you people.


"you people"???
Member Since: March 10, 2006 Posts: 0 Comments: 10034
Quoting Grothar:


Boy, I really missed you people.

Hey Mate, How ya feeling? Glad to see ya back. How's the weather there?
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1048. txjac
Quoting Grothar:


Boy, I really missed you people.


And we missed you ...so happy to see and hear your!
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Quoting Dakster:
caneswatch - LOL... YouTwitFace...




LOL I just had to tell it.
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NAM 00Z link please :) ?
Member Since: October 6, 2007 Posts: 0 Comments: 5927
1045. Grothar
Quoting DontAnnoyMe:


Gro, you can always Photoshop yourself out of it. ;-)


Boy, I really missed you people.
Member Since: July 17, 2009 Posts: 69 Comments: 25321
1044. Dakster
Quoting luigi18:

eso es una tormenta bananera


Coming from the Banana Republic (as we are often called), that sounds appropriate.
Member Since: March 10, 2006 Posts: 0 Comments: 10034
Quoting Grothar:


Isn't that golden sunset avatar a sight for sore eyes :)) Welcome back, Grothar...It's a happy day, for sure.
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1042. Dakster
caneswatch - LOL... YouTwitFace...


Member Since: March 10, 2006 Posts: 0 Comments: 10034
Quoting 996tt:
The models are suggesting the development of the pattern I suggested right after Lee cruised by and this strong seasonal changing front dove through so deeply. BOC storms remain in the BOC. GOM basically gets shut down for business and if one makes it through the Keys area, it will hit Northern Mexico or extreme Southern Texas. This is pretty much the pattern every year when we get a deep diving front that drops temperatures 10 to 20 degrees and signifies a change to fall. We usually just get it in October or November.

Looks like our GOM storm activity will be cut short this year. Nate is prime example. Anyone disagree or have any thoughts. Hate to see out season over, but that front seems to spell the end. I know in years past NHC and TWC have commented on changes in the patterns of tropical storm activity following such fronts.


There may be some truth to it. While I haven't done any heavy research on it, I have noticed that in years past, anomalous ridging typically follows such fronts. A couple of recent occurrences are Marco in 2008, and Earl of 2010.
Member Since: Posts: Comments:
1040. luigi18
Quoting JLPR2:


LOL!


David ,Eloisa,Hugo,Luis .Marilin, eso si tenian power!!!!
Member Since: September 21, 2008 Posts: 0 Comments: 470
Quoting JLPR2:
But afterwards the NAM moves Maria NW?


Just like the NHC want her to do. Seriously, this kind of track remind me of Hurricane Marilyn! A very bad one for the central Antilles and the US and British Virgins
Member Since: October 6, 2007 Posts: 0 Comments: 5927
CV season going down??

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I know this is off topic, but....

They were thinking of merging YouTube, Twitter, and Facebook. They were thinking of calling it YouTwitFace.
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Taking a break
Member Since: August 19, 2006 Posts: 0 Comments: 15725
Anyone has a link to the NAM00Z?? Thanks
Member Since: October 6, 2007 Posts: 0 Comments: 5927
Quoting JLPR2:


We should focus on the rain potential. Any more than 5 inches and all that will be visible from satellite will be the mountains. :\

It's size...is just huge. It could be another disastrous flooding event, what a horrible but possible thought.
Anyways, Good Night.
Member Since: July 7, 2010 Posts: 0 Comments: 5626
1031. JLPR2
Quoting luigi18:

eso es una tormenta bananera


LOL!
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1030. luigi18
Quoting WeatherNerdPR:
Seriously, Maria scares me a little.

eso es una tormenta bananera
Member Since: September 21, 2008 Posts: 0 Comments: 470
1029. 996tt
The models are suggesting the development of the pattern I suggested right after Lee cruised by and this strong seasonal changing front dove through so deeply. BOC storms remain in the BOC. GOM basically gets shut down for business and if one makes it through the Keys area, it will hit Northern Mexico or extreme Southern Texas. This is pretty much the pattern every year when we get a deep diving front that drops temperatures 10 to 20 degrees and signifies a change to fall. We usually just get it in October or November.

Looks like our GOM storm activity will be cut short this year. Nate is prime example. Anyone disagree or have any thoughts. Hate to see out season over, but that front seems to spell the end. I know in years past NHC and TWC have commented on changes in the patterns of tropical storm activity following such fronts.
Member Since: Posts: Comments:
Quoting WeatherNerdPR:

Oh my God Maria is huge!

Do not use the panic button...yet.


For the moment.... that's only 50mph wind gusts and YES a big barell of rain.... We should be carefull because Water Kills...
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1027. JLPR2
But afterwards the NAM moves Maria NW?
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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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