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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What was it,,give me a Bendie Straw and I can Move the Earth?

Welcome bac Kotter.
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Quoting Grothar:


Well, I am not supposed to lift anything heavy, but here you are:





yeaaaaaaaaaaaaaaa now you back to normal bud
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Quoting Grothar:


Well, I am not supposed to lift anything heavy, but here you are:



Grothar, great to see you are well!
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Quoting UKHWatcher:


I accept what you're saying.. respect


Back atcha!

I understand your point. The troll label gets applied hastily sometimes.
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The water is very warm in the southern BOC but it is shallow, meaning its energy can be depleted faster. Notice the lower heat content values, as opposed to just the sea surface temperature.
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Quoting will40:




heyyyyyyyyyyyyyyyyy Gro wb we missed you. Post that Globe lol


Well, I am not supposed to lift anything heavy, but here you are:

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418. jpsb
Quoting blsealevel:
So the US presendent doing his jobless speech
thought i heard almost everyone in louisiana just say WHAT!!

Anyway got some melted cheese with saugae and rotel
and some chips waiting on the game while i look this over

Day 6?

Time to pop a cold one.
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Quoting Grothar:


Are you behaving?

He's picking on me!!!!!
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Quoting vital1:
I would have died right then and there. I'm afraid of heights, clausterphobic and my biggest fear is drowning! That being said, I fly on our hospital's helicopter and take cruises so I'm not as boring as that statement sounds:).

Sorry, usually lurk, but had to respond to this.


Yeah, that would have covered all your fears in one. I can handle helicopters and planes for some reason too...
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Quoting UKHWatcher:


See,read,digest the above... and yes I will!


well...you , too...but I meant to quote Gro....I'm an idiot...
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Conditions at 42055 as of
(5:50 pm CDT)


2250 GMT on 09/08/2011:
Unit of Measure: Time Zone:
Click on the graph icon in the table below to see a time series plot of the last five days of that observation.

Wind Direction (WDIR): N ( 360 deg true )
Wind Speed (WSPD): 25.3 kts
Wind Gust (GST): 33.0 kts
Wave Height (WVHT): 8.5 ft
Dominant Wave Period (DPD): 8 sec
Average Period (APD): 5.4 sec
Mean Wave Direction (MWD): NNE ( 23 deg true )
Atmospheric Pressure (PRES): 29.82 in
Pressure Tendency (PTDY): -0.01 in ( Falling )
Air Temperature (ATMP): 83.5 °F
Water Temperature (WTMP): 84.6 °F
Dew Point (DEWP): 71.8 °F
Heat Index (HEAT): 88.7 °F
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Quoting Levi32:
The warm water isn't very deep down there in the BOC either. A strong TS Nate may be rapidly evaporating that energy away right now. It could negatively impact him if he sits there too long before moving.


You're right. The water temperature may drop from 88F to 86F :)
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Quoting Dakster:


Yep - It did take a long time to get power back. If you were on county water it came back quickly. (a couple of days and a week of boil water before drinking) But a lot of homes are on well water and no power = no water.

Forgot to mention, my mothers apartment at the time on brickell got power back after 2 weeks, we moved in, but the elevators were not working. 34 FLIGHTS OF STAIRS. Then when the elevators started working, I got in to leave for the day, the elevator lost all power (totally dark) and it FELL against the brakes all the way to the basement and into waist deep water. Nothing like being in a coffin with water rushing in. It didn't free fall, but it did fall alot faster than normal. To this day, I am not too fond of elevators...

SO, yes, one Andrew type storm in one lifetime is enough.
I would have died right then and there. I'm afraid of heights, clausterphobic and my biggest fear is drowning! That being said, I fly on our hospital's helicopter and take cruises so I'm not as boring as that statement sounds:).

Sorry, usually lurk, but had to respond to this.
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Quoting Grothar:


Are you behaving?




no no he been a vary bad bad boy LOL





this kinding
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Quoting Grothar:


Hey Gro, how ya feeling. Good to see you on this evening
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Quoting twincomanche:
Hey Gro.


Are you behaving?
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Quoting twincomanche:
You can't poof me. I'm too entertaining to you as you are to me.

I would respond but since I have you on ignore I can't.
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Quoting breald:
Chello everyone, any chance Nate will head up to TX?


Very (x10), Highly (x10) unlikely.
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Quoting twincomanche:
What is your point? Give it a rest.


See,read,digest the above... and yes I will!
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Whooooaaaaa
Grothar back with the pretty pictures.

Welcome back Old Man.
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Quoting Levi32:


General direction of the Mississippi River, but let's first see if the general motion forecast actually verifies lol. It's possible this will be an occasion where I am dead wrong, but a choice has to be made by forecasters in a situation like this when there are two opposing roads. I've made my choice.


I admire your approach. I have a company with over 3,000 employees and contractors. I have to make decisions in my work that I have to stand behind. That goes with the territory. Forecasters have to put a stake in the ground, too. You did that. I admire that quality in people. You may be wrong, but read Masters above. He thinks your solution is very much still in play. We will see more about that tomorrow morning. But, dude, you are good. I look forward to following your career. And since I am in the media business, I might have a role in introducing you to a broader audience. Stand firm.
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Quoting Levi32:


The dry flow from Texas lets up a tad, but it's still there as well, and the GFS 700mb humidity product doesn't show much of an erosion of the dry air field in proximity to Nate, especially if he moves northward. He'll have a much better chance of strengthening if he stays in the BOC and moves west or WSW into Texas, south of the NHC track. If my forecast track had been a southerly option like that, I would have forecasted a strong tropical storm this morning instead of a moderate one. Obviously he's already gotten to strong lol, so that part of the forecast is already dead.


We'll have to see. If Nate can tap into even a somewhat better source of energy that its currently drawing on, given its considerable strengthening in its relative absense, it may turn out to be rather intense and won't take too long to get there. For that, though, it must drift NE. The next day will tell. BYW I really enjoy your tidbits. Well thought out and remarkably comprehensive.
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Chello everyone, any chance Nate will head up to TX?
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So the US presendent doing his jobless speech
thought i heard almost everyone in louisiana just say WHAT!!

Anyway got some melted cheese with saugae and rotel
and some chips waiting on the game while i look this over

Day 6?

Member Since: August 23, 2008 Posts: 0 Comments: 1918
Quoting Grothar:




heyyyyyyyyyyyyyyyyy Gro wb we missed you. Post that Globe lol
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Well, it seems to me that the GFS went back to square one. Now it's saying that Nate will hit the BOC making landfall in Mexico. Am I reading the right GFS? I'm looking at the 18Z Gfs.
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Good afternoon/evening everyone..

so Nate wants to play and attempt to bring more rain to the northern GOM, well, what can I say except I hope that he makes his visit during the week and not rainout my weekend!..lol
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Quoting DFWjc:


wait if we can take Pluto out of the planets classification, why can't we take a tomato out of fruits?

Science confuses me.... :(


We could, but then you would have to change the definition of a fruit. Just like they did with Planet.
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If Nate moves more North and Northeast, he should be much stronger.

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Quoting SPLbeater:
worst looking strong TS award goes to....Ts Nate 2011 hehe lol





Dat aint Nate my friend,,thats the Northeast USA,

Check with Big Bird for the Letter M.


They put the wrong file image in Nate's Floater update.
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Quoting WeatherNerdPR:

Or rotating wall cloud. Or a random low-hanging cloud.
We had a tornado in the West side of Puerto Rico this afternoon, in Aguadilla.
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Quoting PrivateIdaho:


This is a skewed account of recent events. Many people here answered Grandpa's questions with respect, then grandpa started asking for advice, then he started saying he wasn't going to follow the advice, then he says it could be endtimes, then he asks about a banned member, SSIG.

As I have mentioned earlier, the worst kind of troll is the one trying to prey on the good nature of people. I would go so far as to say this is predator behavior.

Kudos to those who give trolls the benefit of a doubt.
Kudos for those who point out these trolls after they expose themselves for what they are.


What, someone exposed themselves on here? :O
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Quoting Levi32:


It's these kinds of make or break forecast decisions that make life exciting for us, right? It's pretty nerve-racking though lol.


You're not on T.V., no need to mess up your nerves :P
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The warm water isn't very deep down there in the BOC either. A strong TS Nate may be rapidly evaporating that energy away right now. It could negatively impact him if he sits there too long before moving.

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Out for now. Gonna go watch my Saints take down the defending champs.
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Quoting Levi32:
Hurricane? Nah.



levi do you think that there is still a chance of nate hitting louisiana
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worst looking strong TS award goes to....Ts Nate 2011 hehe lol
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Quoting twincomanche:
Everyone is entitled to their opinion. People should not be poofed for judt giving their opinion. JMHO.

poof

(sorry, just blowing a bug off my screen)
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Quoting MississippiWx:


StormW agrees with your forecast. So, if you're wrong, you can both go down together. LOL.

For what it's worth, I am still thinking your forecast makes the most sense, so I'll go down with you as well. We'll see.


It's these kinds of make or break forecast decisions that make life exciting for us, right? It's pretty nerve-racking though lol.
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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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