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 BioWeather:
Good morning all! I see the models have shifted a little for Maria this morning AND she woke up a little angrier than yesterday. How is everyone feeling about the new model runs with her shifting further away from the US? Do you agree?


From FL, yes at the moment. From NC/SC? No. I still stand by my original opinion that Maria decides to make a NC visit and not a nice visit either. So send a letter to Maria?

Nate, I still feel is up in the air. I think that if anything the storm is still pretty stationary and IMO I still feel a TX/MX border impact is likely. At 8 am, the results from yesterday late evening flights in the GOM were suppose to be reported and factored into the track forecast. I don't think it has been yet.
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Nate is, IMO, in a strengthening trend also.



UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 09 SEP 2011 Time : 111500 UTC
Lat : 19:57:52 N Lon : 92:21:08 W


CI# /Pressure/ Vmax
3.1 / 998.4mb/ 47.0kt


Final T# Adj T# Raw T#
3.1 3.4 3.6

Center Temp : -55.8C Cloud Region Temp : -35.4C

Scene Type : CURVED BAND with 0.79 ARC in LT GRAY

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : 0.7T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 82km
- Environmental MSLP : 1012mb

Satellite Viewing Angle : 30.6 degrees

************************************************* ***
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Quoting AussieStorm:

It's not the wind I am worried about, It would be the many inches of rain she will bring to them.


Localised flooding is a possibility, but rain is not typically the problem with these. It's the wind and sometimes the surge.
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1724. WxLogic
Based on HH findings... Maria is quite a mess.
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UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 09 SEP 2011 Time : 111500 UTC
Lat : 13:57:05 N Lon : 56:45:37 W


CI# /Pressure/ Vmax
3.2 / 997.8mb/ 49.0kt


Final T# Adj T# Raw T#
3.2 3.4 4.4

Center Temp : -73.9C Cloud Region Temp : -75.0C

Scene Type : UNIFORM CDO CLOUD REGION

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : 0.7T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 125km
- Environmental MSLP : 1012mb

Satellite Viewing Angle : 26.7 degrees

************************************************* ***
OMG!! Maria's Raw T's are 4.4
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1722. SLU
Looks like the recon found another center at 13.6n 55.4w?
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1721. ncstorm
Quoting BioWeather:
Good morning all! I see the models have shifted a little for Maria this morning AND she woke up a little angrier than yesterday. How is everyone feeling about the new model runs with her shifting further away from the US? Do you agree?


Actually the Euro, NOGAPS and CMC have a more western shift with the NOGAPS riding up the east coast..The GFS and UK are still on the eastern route ..
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Link

MEXICO CITY — Mexico’s state oil company says it is searching for 10 workers who were evacuated from a platform in the Gulf of Mexico ahead of Tropical Storm Nate.

Petroleos Mexicanos says in a news release that the workers are employed by Geokinetics Inc., which is based in Houston. Pemex gave few details about the workers or the search in a news release. Calls before business hours Friday to Pemex and Geokinetics were not answered.

Pemex said the workers were being taken off the platform because of the Tropical Storm.


I certainly hope these are not Nate's first casualties.
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Maria may indeed be strengthening.
09/1145 UTC 13.5N 58.0W T3.0/3.0 MARIA
Katia is still a hurricane
09/1145 UTC 38.5N 66.7W T4.0/4.5 KATIA
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Maria's reboot is proceeding. Pressure is down, winds are up:

AL, 14, 2011090912, , BEST, 0, 140N, 570W, 40, 1003, TS, 34, NEQ, 150, 0, 0, 100, 1010, 180, 50, 0, 0, L, 0, , 0, 0, MARIA, M,
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Quoting Dakster:


We must be related as we have the same uncle! The email did not say I had to split the fortune.... Ohh well - off to work...


Oh well! Maybe a distant cousin will show up today?

I'm sure something will change and I am betting on the storm paths.
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Katia is/was close call, it has been interesting following the fluctuations in strength
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Quoting yonzabam:


Only very rarely do these ex-tropical storms retain enough strength to do any damage here in Scotland. There was one called 'Gordon' which brought the odd tree down a few years ago. That was the first in ages. Most of them head on up north of Scotland.

It's not the wind I am worried about, It would be the many inches of rain she will bring to them.
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Quoting yonzabam:


Only very rarely do these ex-tropical storms retain enough strength to do any damage here in Scotland. There was one called 'Gordon' which brought the odd tree down a few years ago. That was the first in ages. Most of them head on up north of Scotland.


This is true, but considering how closely mets are monitoring this particular system, they seem to be giving it due respect. Of course, it could be just because they're aware people will be a little bit more fidgety as they're aware it used to be a bona fide hurricane.

Presently, the intensity and track is not set in stone, but looks like it'll come this way. Currently if things hold, it'll feel very similar to the type of storm that comes around January, just a little earlier in the year.

Things could change, for better or for worse.
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Good morning all! I see the models have shifted a little for Maria this morning AND she woke up a little angrier than yesterday. How is everyone feeling about the new model runs with her shifting further away from the US? Do you agree?
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1712. Caner
Nate still appears tightly wound on the LCP.



The apparent motion to the East overnight on the colorized IR loops may have just been a convection shift.



Reviewing the LCP and non colorized IR this morning, position over the last 6 hours looks stationary, if anything a slight jog to the north.





Link
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Quoting farupnorth:
Can't see any strong winds with recon in Maria yet



Stronger winds being found now.

Link
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1710. Dakster
Quoting wayfaringstranger:
I see this morning that the NHC has once again changed the path for Nate.

I also seen an intensity change for Maria.

Amazing what happens in 24 hrs. Now if I could just convince someone that in 24 hrs to deposit 1 million into my bank acct then that would be another nice change! Of course this morning I got one of those nice spam emails telling me how some long lost departed uncle from the jungles of Nabino left me a fortune.

Good morning to all.


We must be related as we have the same uncle! The email did not say I had to split the fortune.... Ohh well - off to work...
Member Since: March 10, 2006 Posts: 0 Comments: 10312
Quoting TropicalAnalystwx13:
I see clouds...!


I thought that was a make on my screen. lol.
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Quoting AussieStorm:

Thanks for this info, I have forward the link to All my relatives in Scotland to be wary of severe weather on Monday.


Only very rarely do these ex-tropical storms retain enough strength to do any damage here in Scotland. There was one called 'Gordon' which brought the odd tree down a few years ago. That was the first in ages. Most of them head on up north of Scotland.
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1706. ncstorm
Quoting TropicalAnalystwx13:


The Bermuda Triangle..sort of..
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Quoting wayfaringstranger:
I see this morning that the NHC has once again changed the path for Nate.

I also seen an intensity change for Maria.

Amazing what happens in 24 hrs. Now if I could just convince someone that in 24 hrs to deposit 1 million into my bank acct then that would be another nice change! Of course this morning I got one of those nice spam emails telling me how some long lost departed uncle from the jungles of Nabino left me a fortune.

Good morning to all.


lol
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Quoting Cotillion:
"Hurricane Katia off the east coast of the US could cause stormy weather to hit Scotland on Monday, according to forecasters in Miami.

John Cangialosi, at the US National Hurricane Center, told the Reuters news agency that Katia was expected to head out into open sea.

He said it would change from a tropical storm to a "classic wintertime storm" by the time it reached Scotland.

The Met Office has not issued a severe weather warning at this stage.

However, Northern Constabulary said the Met Office had forecast heavy rain and severe gales for large parts of the north of Scotland on Monday.

Hurricane specialist John Cangialosi said Katia would change from a tropical system to a larger storm once it was over open sea and would head for Scotland.

He said: "It'll likely be a very big, significant weather system.

"It will evolve into a classic wintertime storm by the time it gets there."

Link

A warning from the NHC, an article on the BBC about Pat Tillman who tragically died in the line of duty and a lot of coverage on the upcoming 9\11 anniversary.

A very American touch here as of late.

Thanks for this info, I have forward the link to All my relatives in Scotland to be wary of severe weather on Monday.
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I see this morning that the NHC has once again changed the path for Nate.

I also seen an intensity change for Maria.

Amazing what happens in 24 hrs. Now if I could just convince someone that in 24 hrs to deposit 1 million into my bank acct then that would be another nice change! Of course this morning I got one of those nice spam emails telling me how some long lost departed uncle from the jungles of Nabino left me a fortune.

Good morning to all.
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Can't see any strong winds with recon in Maria yet
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Member Since: July 6, 2010 Posts: 113 Comments: 32068
Glad to see the models have finally agreed where to send Nate. We do not need anymore rain. Don't wish any system on anyone (well, Texas could use the rain), but I am glad to see that my weekend will be nice after all.
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1697. WxLogic
Maria is being affected (enhanced) by the ULL to her NW.

Looks like NGP and Parall NAM are depicting in 84HR the same 500MB pattern which puts it closer to CONUS after it traverses PR/DR/Leeward Islands as a weak TS to moderate TS:

06Z NGP 500MB:



06Z NAM Parallel:



06Z GFS:



Even GFS is similar but the key to this is the strengthening phase. It appears GFS is attempting to develop it quite quickly while other models such as ECMWF keeps it weak.
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BULLETIN
TROPICAL STORM MARIA INTERMEDIATE ADVISORY NUMBER 11A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142011
800 AM AST FRI SEP 09 2011

...MARIA HEADING TOWARD THE CENTRAL AND NORTHERN LESSER ANTILLES...


SUMMARY OF 800 AM AST...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...14.0N 56.9W
ABOUT 185 MI...295 KM ENE OF BARBADOS
ABOUT 390 MI...630 KM SE OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES
Member Since: July 6, 2010 Posts: 113 Comments: 32068
I see clouds...!

Member Since: July 6, 2010 Posts: 113 Comments: 32068
The Met Office have now given an advisory, though:

"The remains of Hurricane Katia are expected to come across the UK on Monday bringing a spell of very windy weather. There remains a fair amount of uncertainty about its track and intensity, and warning areas may be extended or upgraded to amber in subsequent issues, but the best estimate currently is that northern and western parts of the UK are most at risk from very strong winds. The public should be aware of the risk of disruption to transport and of the possibility of damage to trees and structures."

Essentially a windstorm watch.

Link
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Yes, Earl affected the Leeward Islands...I remember it rapidly strengthening.

Member Since: July 6, 2010 Posts: 113 Comments: 32068
1688. Gearsts
Coordinates: 13.7167N 57.15W
Acft. Static Air Press: 842.4 mb (~ 24.88 inHg)
Acft. Geopotential Hgt: 1,562 meters (~ 5,125 feet)
Extrap. Sfc. Press: 1007.5 mb (~ 29.75 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 323° at 4 knots (From the NW at ~ 4.6 mph)
Member Since: August 2, 2010 Posts: 0 Comments: 1750
Quoting GTcooliebai:
Judging by the 72 hr. SFC Forecast, there is High directly above Maria when she starts to make her Northwest turn.



depending on where that high settles in, wouldn't that pull Maria into the coast?
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Good morning MARIA! Lol you are pretty
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NATE!! WAKE UP YOU LAZY STORM!

Member Since: July 6, 2010 Posts: 113 Comments: 32068
1682. WxLogic
Good Morning...
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'NO 96-HOUR POINT IS BEING GIVEN BECAUSE FORECAST POINTS IN THE
EASTERN HEMISPHERE BREAK A LOT OF SOFTWARE.'

Lol.

Here there be dragons!

Good job it's not another Faith, that'd cause significant problems.
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Quoting cat5hurricane:

Just having a little fun. No reason to take it so personally :-)


Yeah well you have to admit everyone here is pretty darn good at forecasting what's going to happen with these storms. Its nearly impossible to know what's going to happen so far down the road, so long term projections i tend to take with a grain of salt, and i am glad when they are able to identify the various subtle things that allow these huge weather systems to come together and move across our great earth.
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Quoting cat5hurricane:

This year's Earl.


I'm curious! Did Earl effect the Lesser Antillis?
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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.