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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1177. hahaguy
Member Since: August 12, 2007 Posts: 2 Comments: 2838
1176. Dakster
As far as Nate, sorry Texas.... And congrats to LA/MS/AL/FL... It looks like it will miss all of those states.
Member Since: March 10, 2006 Posts: 0 Comments: 10034
1175. luigi18
Quoting thesituation:
NYAN model shifting West

Link

lol
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1099. thesituation 2:41 AM GMT on September 09, 2011

WTF are you smoking. Irene made a direct landfall in NC


You are correct. I guess my wording was off a little bit. Irene did hit NC, and then glanced off to the North East after that. My statement was wrong. Any time a tropical system hits any land mass, it should be considered a direct hit. Especially when we see what the Bahamas dealt with from Irene and what is happening with the flooding from Lee. I stand corrected. I guess my main point was how Marie looks like it could be a closer threat further south on the US coast line.

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1173. Grothar
Quoting Swede38:
\\

I am Gammal.70+,dont feel like it at all,but still learning every day here. Fascinating.
NC.

Lets both hang in there OK!!!
Tollarp,Skane-Long,long time ago.



Vakre området! Jeg har venner i Helsingborg.

How did you come through with Irene, much flooding near you?
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1172. Relix
11:00 PM AST Thu Sep 8
Location: 13.3°N 54.6°W
Max sustained: 40 mph
Moving: W at 21 mph
Min pressure: 1005 mb
Member Since: Posts: Comments:
Quoting jrweatherman:
Laugh at all you wishcasters in the northern gulf of mexico!

ULD CAUSE NATE TO MOVE MORE
TOWARD THE NORTH AND NORTH-NORTHWEST. THERE HAS BEEN A LARGE MODEL
CHANGE FROM SIX HOURS AGO...WITH THE GFS/GFDL/HWRF MODELS NOW
HAVING A GENERAL WESTWARD TRACK TOWARD MAINLAND MEXICO DUE TO THE
CYCLONE BEING TRAPPED BENEATH A NARROW RIDGE OVER THE NORTHERN GULF
OF MEXICO. NATE IS FARTHER SOUTH THAN EXPECTED YESTERDAY...SO THE
LIKELIHOOD OF A MORE POLEWARD TRACK AHEAD OF THE NEXT TROUGH OVER
THE CENTRAL UNITED STATES HAS DIMINISHED. THUS THE NHC FORECAST IS
SHIFTED WELL TO THE LEFT AT THIS TIME..


Meh.
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Quoting thesituation:
NYAN model shifting West

Link


I bet you make a killer fruitcake.
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Quoting 69Viking:


Wow, if you played in Destin then no doubt I enjoyed listening to you a few times or more. I remember a good band in my younger years playing in Destin called Ba'Nana Republic!



I played regularly at AJ's from about 1992 till 1998.
I was the keyboard player. The white guy.
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1168. Dakster
Quoting HrDelta:


At least it's actually moving, unlike another storm.


They are trying to figure out how to draw the cone without putting Grothar in it...
Member Since: March 10, 2006 Posts: 0 Comments: 10034
It's not 11PM yet after all..
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Quoting Dakster:


I am just going to leave that one alone...

Maybe you and Taz can shower together...
ROFLMAO
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Laugh at all you wishcasters in the northern gulf of mexico!

ULD CAUSE NATE TO MOVE MORE
TOWARD THE NORTH AND NORTH-NORTHWEST. THERE HAS BEEN A LARGE MODEL
CHANGE FROM SIX HOURS AGO...WITH THE GFS/GFDL/HWRF MODELS NOW
HAVING A GENERAL WESTWARD TRACK TOWARD MAINLAND MEXICO DUE TO THE
CYCLONE BEING TRAPPED BENEATH A NARROW RIDGE OVER THE NORTHERN GULF
OF MEXICO. NATE IS FARTHER SOUTH THAN EXPECTED YESTERDAY...SO THE
LIKELIHOOD OF A MORE POLEWARD TRACK AHEAD OF THE NEXT TROUGH OVER
THE CENTRAL UNITED STATES HAS DIMINISHED. THUS THE NHC FORECAST IS
SHIFTED WELL TO THE LEFT AT THIS TIME..
Member Since: Posts: Comments:
1163. HCW
Member Since: August 10, 2002 Posts: 0 Comments: 1408
1162. HrDelta
Quoting CaribBoy:
MARIA is giving headache to the forecasters at the NHC lol


At least it's actually moving, unlike another storm.
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Quoting 69Viking:


Wow, if you played in Destin then no doubt I enjoyed listening to you a few times or more. I remember a good band in my younger years playing in Destin called Ba'Nana Republic!


Yes, no doubt. Me too. Good Times........
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Quoting wxobsvps:


I was wrong. It appears there is a chance that both will impact the CONUS and we should refrain from rejoicing at the moment.



Is that frustration I sense? People on this blog seriously need to develop a thicker skin.
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Quoting HrDelta:
Hmm, both Katia and Nate are out, but not Maria.

Interesting.


Lol sure
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Quoting wxobsvps:


I was wrong. It appears there is a chance that both will impact the CONUS and we should refrain from rejoicing at the moment.



That's a little better, but don't forget the blog motto...."It's never to early to panic!"
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MARIA is giving headache to the forecasters at the NHC lol
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1155. owntime
Quoting txjac:


Almost with you there ..Ike was damaging but we need something to put the fires out and get the ground soaked


Ike was not too bad at my place in Houston other than being without power for almost a month. I planned ahead and had generators, gas and other supplies on hand and we did ok. We took cold showers for two weeks b4 the neighbor offered us a hot shower because he had a N.gas hot water heater, lol. Those showers were cold before hand, and I mean cold.
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Quoting ecflweatherfan:


Really? 61.23"... must be nice to have above normal rain. Over here on the east side of the state, even with a lot of Westerly steering flow this wet season, I have only managed 29.87" on the year so far. Below normal over here. I just dont get it either, westerly flow, you all are getting a lot of rain (typically a very wet pattern for the eastern peninsula, one would think drier for the western side), easterly flow, you get a lot of rain (typically a wet pattern for the western peninsula, dry eastern peninsula)... argh!!! It is driving me bananas.


Yeah its weird isn't it? Ive seen many times where we have a westerly flow and the NWS in Melbourne forecasts higher rain chances than TBW because of westerly flow and we get pounded over here on the West Coast. And yep, the average is about 52 in. here, so we are above average this year!

Why? Well sometimes forecasters follow what should be expected too much, rather than what has been the pattern. Well, what has happened is that in the westerly flow we frequently get large convective blow ups early in the AM here that dump very heavy rain, and then high clouds are spread over the east side of the state limiting heating and thus rainfall.


You have to remember that we have had very little significant systems containing strong dynamics to provide lift outside of heating. Which is why Ive had a lot of heavy rain events but nothing bigger than 5 or 6 inches in 24 hours, we have just had heavy storms several times a week. Mostly because we have had many patterns of weak troughing combined with very high moisture. The very high moisture is almost self destructive for some areas if lift isn't strong enough because storms fire up early in one area and prevent heating everywhere else.

Hey I know this is a mouth full but I'm explaining the weird situation lol.

I have seen that on some years, you know back when there was an east flow. But anyway, sometimes there would be such high moisture combined with troughing to produce very favorable conditions. However with low dynamics it would cause huge blow ups on the east coast in the morning and then we would get less than forecast because heating would be shut out by high clouds from the early storms.
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1153. HrDelta
Hmm, both Katia and Nate are out, but not Maria.

Interesting.
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1151. BDADUDE
Try not to be serious casters dudes. leave it to the pro's.
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Looks like MARIA is the main topic tonight!
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1148. JNCali
"Not so much. I happen to think both will miss CONUS and we can rejoice. Why is that ignorant?"

...Anymore questions?? no? okay.. nothing more to see here..
Member Since: September 9, 2010 Posts: 5 Comments: 1034
1147. hahaguy
Quoting TampaSpin:


The wife has been screaming at the TV tonite.....she took the Saints defense...OOPS! LOL

Ouch bad move.
Member Since: August 12, 2007 Posts: 2 Comments: 2838
Quoting Grothar:


The house is fine. It is very high. But the town is a mess. The river is expected to crest around 2-4 this morning. They are really worried. It is much worse than people thought. The flooding is covering a very large area. Some places are expecting to be under 20 feet of water. They are really worried about Binghamton.


That is not good. I feel sorry for everyone there. This has definitely been a year of disasters and we still have to get through the CV season. I just hope that your house remains high and dry.
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I can't wait for the next NHC advisory. By looking at the models, the cone should be shifted even more to the west. I get the feeling that Nate is definitevly a Mexico event. Are the models crunching the Recon data for this 18z advisory? or will we have to wait till the 00z advisory?
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Quoting DFWjc:


if it wasn't for that GB td return, and 2 sacks.. my DEF points would be 1.0..


The wife has been screaming at the TV tonite.....she took the Saints defense...OOPS! LOL
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Quoting DDR:
CaribBoy what island are you on?
Hope you are prepared?


Yes DDR I'm ready, always ready! Thanks for being concerned about me. I'm in St Maarten (18N 63W). And if my memory is still fine, you are in Tobago.
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Quoting Dakster:


Yep. Me too...


im waiting harder
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Quoting thesituation:




That is wind gusts. I'm talking sustained.
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Quoting hahaguy:


Great game. Good way to start off the season.
Agree
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Quoting redwagon:

NATE

AWAITING MEXICAN RELEASE OF HIS SOUTHERN HALF

It is taking him forever to shove off land. Never seen a shackled cyclone before.


It's a mexican standoff as far as I can tell.
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thanks for advisories guys. wait continues for maria...lets send some1 to miami to rush them lol
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Quoting PensacolaDoug:


I used to be in a band called Ba'Nana Republic.


Wow, if you played in Destin then no doubt I enjoyed listening to you a few times or more. I remember a good band in my younger years playing in Destin called Ba'Nana Republic!
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Quoting DFWjc:


if it wasn't for that GB td return, and 2 sacks.. my DEF points would be 1.0..
Yep a 108 yds. to be exact, Cobb just wasn't going to be denied a touchdown.
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Don’t think we will see much of a change in Maria’s forecast cone in a few minutes. Some parts of south Fla. will probably be in it. But the overall track will still keep it off the coast.
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1131. Relix
F5F5F5F5F5F5F5F5F5
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1130. Grothar
Quoting Some1Has2BtheRookie:


Have you heard any news on your house?


The house is fine. It is very high. But the town is a mess. The river is expected to crest around 2-4 this morning. They are really worried. It is much worse than people thought. The flooding is covering a very large area. Some places are expecting to be under 20 feet of water. They are really worried about Binghamton.
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Quoting SPLbeater:
waiting on advisories

NATE

AWAITING MEXICAN RELEASE OF HIS SOUTHERN HALF

It is taking him forever to shove off land. Never seen a shackled cyclone before.
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Quoting Dakster:
We won't have to worry about a 30 - 34 score anymore...

Probably more like 48 - 49.
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1127. Sangria
Quoting Jedkins01:



Me too, I live in north Pinellas County, Ive had 61.23 inches this year now, and most of that falling since when the rain season finally kicked in late June.

Last year I had only 39 inches for the entire year, which is 13 inches below normal. This year I'm already above normal.

Its rain so much, for quite a while now that even on dry days, water is literally coming out of the ground and draining into the drain gutters even if it hasn't rained. Wherever there is grass, it feels like you walk on a soaked sponge lol.

We certainly don't need a hurricane, we never do, and we don't want one. Thank God we haven't had to deal with them in a while. Texas does not need one either, it won't solve the problem, it will bring more destruction than help. Even if it brought enough rain, it would bring devastating floods than return to drought. Texas needs a long term pattern change, it will take a while to get heavy rains falling in an area that parched, just look at the dust bowl, for example.


And as I sit here and read the blog....it begins again. I am in Pasco (NPR), and the rain has just started up..
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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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