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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Quoting FrankZapper:
Saints 34 Green Bay 30 OT


I like that I'll go saints 38 packers 31 you do realize that that score isn't possible though
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What's going on in San Diego? No power in Southern California and they are not saying why...
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525. HCW
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523. DFWjc
Quoting Patrap:


That cant happen.

There's no 4 point play in the NFL last I checked.

But the Fresca and Southern Comfort has started to flow here..so I best refer to Gro.

33 to 30 will work though.


that would kill me on FF, i need like a 17-14 NOLA win..
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Quoting Seflhurricane:
NATIONAL WEATHER SERVICE MIAMI FL
225 PM EDT THU SEP 8 2011

...SOUTH FLORIDA NEEDS TO CONTINUE TO MONITOR TROPICAL STORM MARIA
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...



Why we have been since May I thought?
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Boy, you guys are really in top form with the sarcasm tonight. I haven't seen that much since Mrs. Grothar told me what I nice job I did on the fence.
Member Since: July 17, 2009 Posts: 69 Comments: 25421
Good evening i see models r all over with nate?? Just wanted to ask if he will affect the northern gulf ooast or turn into mexico??
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NATIONAL WEATHER SERVICE MIAMI FL
225 PM EDT THU SEP 8 2011

...SOUTH FLORIDA NEEDS TO CONTINUE TO MONITOR TROPICAL STORM MARIA
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...

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Quoting hurricanehunter27:
LOL i just got back from it, it was ok... was like a good TV movie.

Lunar crabs.
Two Thumbs DOWN.
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Quoting presslord:


Terror Alert Level: Mauve


glad it's not taupe.....hate taupe.
Member Since: August 29, 2010 Posts: 0 Comments: 5236
Quoting FrankZapper:
Saints 34 Green Bay 30 OT


That cant happen.

There's no 4 point play in the NFL last I checked.

But the Fresca and Southern Comfort has started to flow here..so I best refer to Gro.

33 to 30 will work though.
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Quoting JrWeathermanFL:
A lot of TSs dont gt retired, but this one could come close...


I am well aware that Tropical storms don't get retired. Only one has been retired since the past 40 somewhat years we had a naming system.

Tropical Storm Lee and Tropical Storm Allision of 2001 are very similar in terms of flooding. They post caused historical flooding to certain places that really couldn't take it. Lee seems to be almost just as bad.

The only other Tropical storm that comes into recongnition for retirement to me in the past few years could have been Fay of 2008. Dumped almost as much rain as Allison but did not cause as bad of flooding like Lee of this year and Allsion of 2001.

Its really tough to say.
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Quoting Grothar:


Twit! :)


I am delighted to see you have risen!!!!
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Did nate lose his floater? I clicked over to the tab with his floater on it (from the nhc site) and it's showing Katia instead.
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Quoting GeoffreyWPB:
Hi Gro....Didn't know you were sick. Hope you are feeling better.


Twit! :)
Member Since: July 17, 2009 Posts: 69 Comments: 25421
Saints 34 Green Bay 30 OT
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Quoting Dakster:


But of course, what were you referring to Ally?


no comment..lol
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It is funny how the NHC will put the cone just up to Florida, but not even on the border...

They really wait until they absolutely, positively HAVE to include Florida in the cone to do so. Or at least it seems this way to me.

Not that I currently expect Maria to hit Florida, it is just funny to watch the NHC and the cone placement!
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Quoting Dakster:
And you gotta love CNN....

Specific, Credible, Unconfirmed and Non-Detailed threat against the US...

Ok... That helps.


Terror Alert Level: Mauve
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What is the solution on the latest GFS run, did it change much?
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Quoting PensacolaDoug:
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.




When it comes to track forcasts, it's hard to bet against the NHC. Anybody that goes against them has big brass ones!


Yo, Doug! Thanks for the note on the blog. P.S. Where's IKE?
Member Since: July 17, 2009 Posts: 69 Comments: 25421
sorry Mr. Levi I didn't understand what you said.... pls translate that for me :(
San Juan PR..
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Hi Gro....Didn't know you were sick. Hope you are feeling better.
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Quoting PrivateIdaho:


The painkillers are making you weak....really weak.


I was able to kick them aside today... Now I can manage on advil. Hopefully tomorrow I won't have to take that either.
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Latest Frame shows the Pop continuing over the CoC

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Good evening

Maria is closing in on the "sweet spot" near 55W and as usual for weak systems that get to this position it is firing up to put on a show LOL
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BULLETIN
TROPICAL STORM MARIA INTERMEDIATE ADVISORY NUMBER 9A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142011
800 PM AST THU SEP 08 2011

...MARIA CONTINUES QUICKLY WESTWARD TOWARDS THE LESSER ANTILLES...


SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...13.2N 53.6W
ABOUT 490 MI...790 KM E OF THE WINDWARD ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 21 MPH...33 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES
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Quoting twincomanche:
Be afraid....be very afraid. Or maybe not so much.


Right.... We have specific information that is credible, but unconfirmed. (so how can it be credible and unconfirmed?) And we are not going to tell you what, where, or when - but look out for it.
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Quoting kaiden:
Hello Grother, glad to see around.
Quoting TropicalAnalystwx13:


Hey Gro.


Hi, guys. At least I came back to some active tropics.
Member Since: July 17, 2009 Posts: 69 Comments: 25421
Quoting Dakster:


If I couldn't lift anything heavy I would have trouble going to the bathroom...


The painkillers are making you weak....really weak.
Member Since: August 29, 2010 Posts: 0 Comments: 5236
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8:00 PM AST Thu Sep 8
Location: 13.2°N 53.6°W
Max sustained: 40 mph
Moving: W at 21 mph
Min pressure: 1005 mb
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BULLETIN
TROPICAL STORM NATE INTERMEDIATE ADVISORY NUMBER 5A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL152011
700 PM CDT THU SEP 08 2011

...NATE NEARLY STATIONARY IN THE BAY OF CAMPECHE...


SUMMARY OF 700 PM CDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...19.7N 92.2W
ABOUT 110 MI...180 KM W OF CAMPECHE MEXICO
ABOUT 175 MI...285 KM NE OF COATZACOALCOS MEXICO
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...STATIONARY
MINIMUM CENTRAL PRESSURE...994 MB...29.35 INCHES


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SSTs are already falling steadily 170 miles north of Nate due to steady winds over the last 2-3 days.

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Quoting presslord:
just saw Apollo 18...really wish I'd spent that money on crack, instead....
LOL i just got back from it, it was ok... was like a good TV movie.
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Quoting Grothar:


I believe Dak was referring to the lid. :)


Gro!!! My goodness we wre all so sad glad to have you back on board!!!
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Quoting Speeky:
Who thinks Lee may get retired?
A lot of TSs dont gt retired, but this one could come close...
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Quoting Grothar:


Don't let it worry you. I was wrong once. It doesn't hurt as much as you think.


True, I overslept once,but the Baby Ben was off I still think.
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Quoting Levi32:


Well I hope you fully recover soon...

I both love and dread these wild situations. It provides a great opportunity to make a forecast without as much bias towards the models, but it also means a larger chance of being dead wrong lol.


Don't let it worry you. I was wrong once. It doesn't hurt as much as you think.
Member Since: July 17, 2009 Posts: 69 Comments: 25421
Quoting Grothar:


I believe Dak was referring to the lid. :)


But of course, what were you referring to Ally?
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Great speech! The world is saved! Even funds to keep Nate away! God Bless The President!
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480. DFWjc
Quoting twincomanche:
Our Dear Leader is done. Let the football begin!!!!


Getting the Margarita's ready, cheese dip done, pizza cooking, and let's go NOLA!!!
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479. HCW
Quoting FLdewey:


Might help your forecasting skills.


Wouldn't he have to go to Uranus to be a great forecaster ?
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State College
NEXRAD Radar

Storm Total Surface Rainfall Accumulation ° Elevation
Range
124 NMI

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Quoting twincomanche:
Our Dear Leader is done. Let the football begin!!!!


Well, he wanted to speak last week, but this is the only date the republicans were available.
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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.