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 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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376. Asta
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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.


I accept what you're saying.. respect
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Quoting Progster:


At T 33 on the GFS, the low level flow shifts to a path primarily from the Carribean and eastern Gulf. At that point (provided the GFS is accurate to that point) we could see significant intensification. If you look at the link you can see the streamflow evolution.

Link


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.
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I have a question off topic, why is it when you see people on here that are not on here hardly or at all, want to light someones fire and cause issues, don't get it, give it a rest.
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center is just barely south of the convection, entering now lol
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Quoting TropicalAnalystwx13:


But thats my point -- If it isn't a troll, I'll be more than happy to answer it. However, if it somebody who is posting crazy stuff on this blog and making fun on people and national organizations, then I'm not answering anything.

Why are we having this conservation? :P


We are having this conversation because there are many people reading who see THREE storms in the picture and many people watching who are concerned about there future course.

I'll repeat, this blog should be informative

Some statements such as:

Nate and Maria are going to rumble into NO as a cat5 monster. All my 65 ensemble members are unified in this scenario. Don't ask me how I know this.

should be ignored/reported, but lurkers who read it don't see a counter argument, just finger pointing.

My point is, don't feed the trolls, ignore/report them. Counter them without quoting them and ensure those in (maybe false) fear of their livelihoods keep calm.

Put it another way...

Would you, in the face of evidence right now, Post. "Maria and Nate will definitely not interact and there is no chance whatsoever of New Orleans facing a Cat 4/5 hurricane in the next week"?

I wonder how many Ike/Katrina/Wilma/Rita casters would have been declared trolls in their day, given the forecasts they were commenting on?

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Quoting MississippiWx:


If he is, so what? He's right waaaaay more often than he is wrong. He's using his own knowledge to forecast, not the models. Isn't that what people on here complain about so much? How humans have grown too dependent on computers?

He has great points and it takes courage to stick with a forecast that the models don't agree with in the end result.


Well if you ever try to forecast weather you will get burn on more than one occasion lol But In my opinion if Nate chose a path toward the Northern Gulf Coast it would already started it Northward motion but instead it has been drifting south since yesterday..

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368. Asta
Quoting jpsb:
I would not be so sure of that, I watched the tidbits today and what Levi said made perfect sense to me. Nate is NOT going to go into the Texas death High sitting in N. Mexico so it's either sw or ne and we all now how T.C. like to go north. I've got 5 on Levi ;)

I agree.
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Quoting Levi32:
Hurricane? Nah.



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.
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maria looks better, doubt she will be TD anytime but still possible
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365. DFWjc
Quoting Dakster:


I don't make the rules...


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

Science confuses me.... :(
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Quoting Cantu5977:


Im surprise by your forecast and it looks like your going to be dead wrong...


poof....
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Quoting Levi32:
Hurricane? Nah.

But levi look at that small area of intense convection! ;)
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362. jpsb
Quoting Cantu5977:


Im surprise by your forecast and it looks like your going to be dead wrong...
I would not be so sure of that, I watched the tidbits today and what Levi said made perfect sense to me. Nate is NOT going to go into the Texas death High sitting in N. Mexico so it's either sw or ne and we all now how T.C. like to go north. I've got 5 on Levi ;)
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Quoting TropicalAnalystwx13:


Making a Tomato a fruit was a mistake IMO...everybody knows it SHOULD be a vegetable.

LOL.


I don't make the rules...
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TS NATE


Storm Relative 1km Geostationary Visible Imagery

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Quoting GTcooliebai:
I never seen this map before, Good stuff Taz.



thanks
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Convection really starting to explode around Nate as shear decreases.
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Quoting Levi32:


Some, but look at the moisture values hitting the southern coast of the BOC lol.



At T+33 on the GFS, the low level flow shifts to a path primarily from the Carribean and eastern Gulf. At that point (provided the GFS is accurate to that point) we could see significant intensification. If you look at the link you can see the streamflow evolution.

Link
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Quoting UKHWatcher:


TA13... Maria and Nate are moving closer together, may even interact... Who knows?

Pls look at the question IT IS VALID, not just who posted it.

You may be on a permanent troll hunt like one or two others, but the rest of us are here for info and if we haven't asked the question ourselves, because we might feel stupid in the presence of such superior minds, we are hardly likely to ask again if other's questions are dealt with so severely.

New people come on here every day, especially if the cone is heading their way. Some of those in fear for their lives.

Recently Grandpato4 was savaged during Irene early on for asking if it would affect Florida. Whether he was a troll or not, there were a thousand lurkers from Florida who probably daren't ask the same question for fear of ridicule.

Thankfully some folk answered his question rather than declaring him a troll. This blog should be informative. What's seems like a dumb "wind up" question might be from someone who's "Heard there's a possibility" who may never have experienced TS or H conditions before. Concerned, they Googled TS/H XXXXX's forecast and found the blog (like I did) and thought... These people might be able to inform me.


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.
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Hurricane? Nah.

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Quoting Tazmanian:
I never seen this map before, Good stuff Taz.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
intense convection firing now with nate on the latest visible... HAWT TOWAHS? ;)
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Quoting Dakster:


Intelligence and Wisdom are two different things... I think I read this here awhile back.

Intelligence is knowing that a Tomato is a Fruit, Wisdom is knowing not to put it in a fruit salad...



Making a Tomato a fruit was a mistake IMO...everybody knows it SHOULD be a vegetable.

LOL.
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Quoting Gearsts:
Way too early to say.


IMO the Northern Gulf Coast is out of the woods with regards to Nate. 12zECMWF Ensembles are narrowing in on a landfall anywhere from Tampico to NE Mexico.
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Quoting UKHWatcher:


But you DID respond!

Look at the bigger picture. You're a really bight kid, but not everyone has your intelligence!

Think about how you would explain things to the slow kid in your class?

Don't quote the troll but post the answer to the question anyway.

As in 'in my belief, the storm will/will not go east/west and will/will not hit x

Match your maturity to your intelligence and think about those who just watch the blog... some in fear of being laughed at if they ask what seems a dumb 'trollish' question to you.

Would love to see "numbers online now" figures for WU. It would give people a different perspective to how big the audience is, not just the 100 or so people who are confident to post!


Intelligence and Wisdom are two different things... I think I read this here awhile back.

Intelligence is knowing that a Tomato is a Fruit, Wisdom is knowing not to put it in a fruit salad...

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348. LBAR
Quoting MississippiWx:
The 70mph intensity is starting to become a little more believable in satellite appearance.



You can just see him sucking in that dry air from w/sw. This is why I love "the weather". So many dynamics come into play.
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Think Shear and/or dry air has let up for the time being, appears Maria is trying to become better organized.

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Quoting Cantu5977:


Im surprise by your forecast and it looks like your going to be dead wrong...


If he is, so what? He's right waaaaay more often than he is wrong. He's using his own knowledge to forecast, not the models. Isn't that what people on here complain about so much? How humans have grown too dependent on computers?

He has great points and it takes courage to stick with a forecast that the models don't agree with in the end result.
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Quoting TropicalAnalystwx13:


I see an overshooting top.




may be a eye wall is froming
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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.
That's why I ask folks like you on here. I know when all is said and done and the models and whatnot have it pretty much pegged to turn to local news and emergency agencies for info, but folks like like you with some knowledge isnt scared to go out on a limb and choose a side so to speak. just gives stuff to think about and not let your guard down just because the models arent heading for your area. And you provide good reasoning and proof behind your comments and predictions. There are a few folks on here like that and i think i speak for just about everyone when i say it is greatly appreciated what you guy's do on here to try and help folks and keep people informed on what could possibly happen
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Quoting Levi32:


Yes. The GFS has been bouncing from coast to coast. The ECMWF ensembles are solidly on Mexico now but we have a while yet to work this out.


Your on the right track Levi32
Remnents of lee or trof might just pull this north
looks like this is going to be another timing issue
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Quoting MississippiWx:
The 70mph intensity is starting to become a little more believable in satellite appearance.



I see an overshooting top.
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Quoting Cantu5977:


Im surprise by your forecast and it looks like your going to be dead wrong...
Way too early to say.
Member Since: August 2, 2010 Posts: 0 Comments: 1993
Quoting GeoffreyWPB:
Hey Levi....Maria...Close call for so. Fla. or an easy miss?


Not an easy miss, but I do think a miss. It's probably going to be one of those storms that comes painfully close and then hooks out very sharply, not an east coast runner like Irene. The U.S. should keep an eye on her, but I do think ultimately she'll miss.
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Quoting BahaHurican:
LOL... an ant bit me today...

Lol, everything is normal in your neck of the woods....I'm enjoying the pleasant weather here in sw la. If mosquitoes were any indication of hurricanes, we would be in trouble here. My dog just got carried away by a Lee- spawned cloud of them! Lol
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The 70mph intensity is starting to become a little more believable in satellite appearance.

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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.


Im surprise by your forecast and it looks like your going to be dead wrong...
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Good Afternoon Eeryone,
Just got out from football practice...
So i see that we have Nate intensifying a lot faster than anticipated, Man that BOC can really crank da storms.
Maria weakening, so a further west solution now eminent. US needs to keep one eye on Nate, One on Maria, As well as the Caribbean Islands(On Maria). Should see Nate a Hurricane at the most the 5 AM/11AM tomorrow, the convection finally getting over top of the circulation fully. Maria should be downgraded to a Tropical depression at the 5 AM, she's looking pathetic...
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Quoting Levi32:


Strengthening increases his attraction to the upper trough to the north, but if he remains at such a small size then it's not as great of an effect. In this case though, the rule of thumb that stronger storms move north does hold. We'll just have to see if all of the factors add up enough to get the northward track.


Thanks, sure do appreciate your knowledge and sharing with all of us.
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Quoting justsouthofnola:


geuss you dont either he asked levi not you...

You are right but dont ask the same exact question over and over again he just asked that same question less than an hour ago just saying.
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Member Since: August 2, 2010 Posts: 0 Comments: 1993
Quoting JNCali:
Folks who claim to be afraid to post a question on this blog are always suspect.. If they are genuine in their attempt and not trying to be too cute (or too humble) I've seen nothing but positive responses from the blog vets. That's how I've been treated and I'm truly thankful. JMO

As a very long-time lurker, I've found that whenever I rarely DO pose a question, I nearly never get a response from anyone. That only serves to reinforce my lurking habits.

/slinks back away
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Hey Levi....Maria...Close call for so. Fla. or an easy miss?
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Quoting flhurricanesurvivor:
Levi,

Does the intesification of Nate change your track reasoning any? Do you still think he will nudge between the highs to N or NE? Will the trough have any effect if he is a stronger than anticipated storm?

Thanks


Strengthening increases his attraction to the upper trough to the north, but if he remains at such a small size then it's not as great of an effect. In this case though, the rule of thumb that stronger storms move north does hold. We'll just have to see if all of the factors add up enough to get the northward track.
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Quoting LBAR:
Maria starting to fire up again!


---

Yup, usually these systems seem to weaken in the afternoon and pull together well overnight.

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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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