Superstorm Sandy and the importance of polar orbiting satellites in forecasting

By: Dr. Jeff Masters , 8:19 PM GMT on January 03, 2013

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On the 23rd of October, the 18th named storm of the 2012 Atlantic hurricane season, Tropical Storm Sandy, was born in the Central Caribbean. As is common for late-season storms in the Caribbean, Sandy moved northwards across Cuba. The official forecasts from the National Hurricane Center issued on October 23 called for Sandy to turn to the northeast after crossing Cuba, and head into the Central Atlantic. This forecast was based on the output from five of our top six computer models, which all predicted that an upper-level low pressure system in the Central Atlantic would be strong enough to pull Sandy northeastwards. However, the global weather forecast model run by the European Center for Medium-Range Weather Forecasts (ECMWF) showed a disturbing possibility: the upper-level low pressure system in the Central Atlantic would not be strong enough to turn Sandy to the northeast. The hurricane would instead get caught up in the flow associated with a trough of low pressure approaching the U.S. East Coast, and Sandy would get slung into New York or New Jersey on October 29. While the ECMWF model was the best performing model for tracking Atlantic hurricanes in both 2010 and 2011, and had done very well again so far in 2012, the American GFS model had outperformed the ECMWF model several times during the 2012 season. NHC elected to discount the ECMWF forecast for Sandy as an outlier, and went with the forecast from the GFS and other models. By October 25, it was clear that the ECMWF model had the right idea all along. More models were now showing the turn towards New York, and the official NHC forecast now called for Sandy to make landfall in New York or New Jersey on October 29. The ECMWF model's early forecast of a track for Sandy into the Northeast was critical for allowing additional time for residents to prepare for arrival of the devastating storm. So what enabled the ECMWF model to make such an excellent forecast for Sandy, six days in advance?


Figure 1. This image uses the model output from the ECMWF experiment, showing where Sandy was predicted to be located five-days out with the normal satellite data inputs into the model (left) and without any polar-orbiting satellite data (right). Both position and intensity forecasts were affected--Sandy stays out to sea without the polar-orbiting satellite data, and the closer isobar lines encircling the storm also imply a more organized and stronger system. Image credit: NOAA.

Polar satellite data: a key to ECMWF model success
The ECWMF has a very sophisticated technique called "4-D Var" for gathering all the current weather data over the Earth and putting the data on a 3-dimensional grid that is then used as the initial "reality" of the current weather for the model to use for its forecast. The old expression, "garbage in, garbage out" is a truism for weather forecast models. If you don't properly characterize the initial state of the atmosphere, the errors you start off with will grow and give a lower-quality forecast. Data from geostationary satellites, which sit continuously at one spot above the globe, are easy to assimilate, and all the models use this data. However, the ECMWF model's superior technique used to assimilate the initial data allows inclusion of data from a large number of polar-orbiting satellites, which the other models cannot do as well. Polar-orbiting satellites orbit Earth at an altitude of 540 miles twice per day, circling from pole to pole. Their data is difficult to use, since the it is only available twice per day at each spot on the Earth, and the time of availability is different for each location. According to an email I received from Jean-Noël Thépaut, the chief of the Data Division of the Research Department at the European Center for Medium-Range Weather Forecasts, the ECMWF model uses data from at least fourteen polar orbiting satellites: N-15, N-19, N-19, N-17 (ozone SBUV instrument only), Metop-A, AQUA, NPP (ATMS instrument only), AURA (ozone OMI data only), F-17, TRMM (TMI data), COSMIC, GRACE-A, TERRASAR, and the GPSRO data on top of METOP-GRAS. The data of most importance is the data collected in the infrared and microwave wavelengths, as well as atmospheric density data obtained via GPS radio occultation (as a polar orbiting satellite goes over the horizon, the GPS signals from the satellite get bent by Earth's atmosphere, with the amount of bending proportional to the density of the atmosphere. This GPS Radio Occultation data is gathered from eight polar orbiting satellites, and fed into both the ECMWF and GFS models.) You can find a nice summary of the impacts of polar orbiting satellite data on weather prediction models at this link.)


Figure 2. Forecast track error for four of our top models used to predict Hurricane Sandy, for their runs that began at 00Z October 25, 2012. By this time, the GFDL model had joined the ECMWF in predicting that Sandy would make landfall in Southern New Jersey in five days. The GFS and HWRF models made good 1 - 3 day forecasts, but failed to anticipate Sandy's north-northwestward turn towards the U.S. coast. Image credit: Morris Bender, NOAA/GFDL.

As originally reported by the Washington Post's Capital Weather Gang, then confirmed in a NOAA press release, a study done by ECMWF research scientist Tony McNally found that if the ECMWF model did not have all of the data from the fourteen polar orbiting satellites, the five-day forecast of the model for Hurricane Sandy would have shown Sandy missing the Northeast U.S. This brings up a concern, since the U.S. polar orbiting satellite program is behind schedule. As explained by Andrew Freedman of Climate Central, the program is plagued by mismanagement, billions in cost overruns, and technical development challenges. The next polar orbiting satellite is not scheduled to be launched until 2017, and one or more of the existing polar orbiting satellites are expected to fail before then. This will result in a degradation of our ability to observe and predict the weather, and may result in poorer forecasts for storms like Hurricane Sandy. Given that the ECMWF model used data from fourteen polar orbiting satellites, the failure of just one satellite may not have made a significant difference in its forecast for Sandy. But if we lose several of these key satellites by 2017, our hurricane forecasts in 2017 may be worse than they were in 2012. To figure out how to cope with the loss of satellite-derived data, NOAA is conducting a Gap Risk Study that seeks ideas from researchers and the public on how NOAA can preserve the quality of its weather model forecasts in the event of the failure of one or more polar orbiting satellites in the coming years.


Figure 3. A tanker rests on the southern shore after being swept onto land by a storm surge due to Superstorm Sandy, Friday, Nov. 2, 2012, in the Staten Island borough of New York. (AP Photo/ John Minchillo)

Links
Eric Berger of the Houston Chronicle has an interview with Jean-Noël Thépaut, chief of the Data Division of the Research Department at the European Center for Medium-Range Weather Forecasts, on why the European model did so well with Hurricane Sandy.

Jeff Masters

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1098. VR46L
Quoting Neapolitan:
Optimism is good--but I've found that some are so blinded by optimism and/or denial that they see the glass half full when it's really got just a few drops left in it. I'm personally neither an optimistic "glass half-full" nor a pessimistic "glass half-empty" type; I'm just a realist. I think that's the best way to be...


When Pandora's box was opened all that was left was hope...I know its only a fable . but its the way I choose to lead my life and if you can label that denial then I wont see the negativity that I perceived previously from that label , instead as a label of optimism ..
Member Since: March 1, 2012 Posts: 0 Comments: 6950
1097. VR46L
.
Quoting TomballTXPride:







Precisely.








Funny enough very rarely are the less pessimistic 8-14 day charts published on this forum.
Member Since: March 1, 2012 Posts: 0 Comments: 6950
1096. bappit
Quoting MahFL:
Remember folks, bush fires and wild fires are part of the Earths natural cycle, they are needed. It's tough luck if your home is burnt to the ground....

From the USDA Forest Service:

"Homeowners and others are not powerless against wildfires. In fact, homeowners who exercise common sense tactics, such as clearing brush and debris away from structures, play a vital role in slowing the spread of fire and protecting their property."

This 2011 news release lists some things to do.

Edit:Also check out www.firewise.org.
Member Since: May 18, 2006 Posts: 10 Comments: 6093
Quoting VR46L:


Yeah , I guess some folk see a half full glass while others half empty... I am a half full glass kind of person LOL
Optimism is good--but I've found that some are so blinded by optimism and/or denial that they see the glass half full when it's really got just a few drops left in it. I'm personally neither an optimistic "glass half-full" nor a pessimistic "glass half-empty" type; I'm just a realist. I think that's the best way to be...
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Quoting TomballTXPride:




You know Liz, I tend to agree with that.

It's the same old song and dance for the gloom and doom posters here.

Remember this: Beginning of December 2011.



And then came this:










And that equaled this: Beginning of April 2012



Nuff Said.


So that's your prediction?
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1091. VR46L
Quoting TomballTXPride:




You know Liz, I tend to agree with that.

It's the same old song and dance for the gloom and doom posters here.

Remember this:



And then came this:










And that equaled this:



Nuff Said.


Yeah , I guess some folk see a half full glass while others half empty... I am a half full glass kind of person LOL
Member Since: March 1, 2012 Posts: 0 Comments: 6950
1090. LargoFl
Looks like Chicago is warming up some.......
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1089. LargoFl
wow those northwestern states get some bad storms huh...
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1087. LargoFl
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At it's worst for TX







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Quoting TropicalAnalystwx13:

Somebody predicted a magnitude 7.5 earthquake off the coast of Alaska three weeks ago. Timing was a bit off, but he/she nailed location and strength.

Not sure if it was this user (@earthquakejapan) or not.


I dislike the prediction anyway...
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Quoting RitaEvac:
Be nice to see these colors lighten up even more, huge thing about a drought is that it mentally wears on you, all the negative you see and hear, it takes its toll on you. For those in the World going thru droughts and fires like Aussie currently I feel for you and I understand what you are going through. At least there are not any fire dangers here that is a huge relief.
Member Since: July 5, 2009 Posts: 0 Comments: 1348
1083. VR46L
Quoting RitaEvac:


I dont think it will look quite like that come next Week lol ...(I know that its a monthly chart) but I doubt it will be as grim looking next month...
Member Since: March 1, 2012 Posts: 0 Comments: 6950
1082. LargoFl
tuesday plse heed your local warnings still too far out to predict severe stuff ok.............THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
AND SOUTHWEST ARKANSAS...NORTH CENTRAL AND NORTHWEST LOUISIANA...
SOUTHEAST OKLAHOMA...AND EAST AND NORTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT...

NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...

A VIGOROUS UPPER LEVEL STORM SYSTEM WILL DIVE INTO NORTHERN MEXICO
MONDAY AND SLOWLY MEANDER EASTWARD TOWARDS THE SOUTHWEST BIG BEND
AREA OF TEXAS BY WEDNESDAY. RAIN WILL BE INCREASING ACROSS THE
WESTERN HALF OF OUR REGION INCLUDING NORTHEAST TEXAS DURING THE DAY
TUESDAY...WITH MORE WIDESPREAD RAINFALL EXPECTED TUESDAY NIGHT INTO
WEDNESDAY ACROSS THE REMAINING PORTIONS OF THE FOUR STATE REGION. DUE
TO THE SLOW MOVEMENT OF THIS UPPER TROUGH TO OUR WEST...VERY HEAVY
RAINFALL WILL LIKELY SET UP ACROSS THE REGION TUESDAY NIGHT THROUGH
AT LEAST WEDNESDAY NIGHT...AND PERHAPS EVEN INTO THURSDAY. FLASH
FLOODING WILL LIKELY BECOME A CONCERN ACROSS AT LEAST PORTIONS OF
THE REGION WEDNESDAY THROUGH WEDNESDAY NIGHT. SEVERE WEATHER
PROBABILITIES ARE MUCH MORE DIFFICULT DO DISCERN THIS FAR...BUT
WITH MORE INSTABILITY ALONG AND NEAR A WARM FRONT NEAR THE
INTERSTATE 20 CORRIDOR OVER TEXAS AND ACROSS LOUISIANA AND
AHEAD OF A COLD FRONT THAT WILL ADVANCE EAST...THE RISK FOR
STRONG AND SEVERE THUNDERSTORMS WILL BE GREATER. LOCALLY
HEAVY RAINFALL OF TWO TO FOUR INCHES WILL BE POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF EMERGENCY MANAGEMENT PERSONNEL...AMATEUR RADIO
OPERATORS...AND STORM SPOTTERS WILL NOT BE NEEDED TODAY OR TONIGHT.

$$

06
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You shall not pass?
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1079. LargoFl
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Quoting TomballTXPride:






LargoFl ~

You are by far one of the best posters here.

You always post relevant weather related information, maps, and graphs.

I love it.

Keep up the good work!








I would agree with that about 150 percent, I sign on and check out Largo's maps and I am good for the day, LOL
Member Since: July 5, 2009 Posts: 0 Comments: 1348
Quoting RitaEvac:


Good luck out there Dennis
Thanks you too, I am so not concerned about a flood here but I can see East and Southeast Texas getting flooded.
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1076. LargoFl
the farther away from the gulf the less rain.....
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1074. LargoFl
Quoting bohonkweatherman:
Good Morning Largo, last time Austin had over 1 inch of rain in 1 day was 99 days ago, that should end Tuesday. Have a great day!
good morning!!..if this pans out, enjoy the rains!!..one thing i noticed this morning, they took out most of the severe warnings..lets see what happens tomorrow am...
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1073. LargoFl
good they are doing this before the hurricane season...WEATHER DEPENDING...THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
SHREVEPORT LOUISIANA WILL RECEIVE A DUAL POLARIZATION UPGRADE TO THE
NWS DOPPLER RADAR IN SHREVEPORT. THE UPGRADE WILL BEGIN ON MONDAY...
JANUARY 21 2013...AND LAST ONE TO TWO WEEKS. THE DOPPLER RADAR WILL
BE OUT OF SERVICE UNTIL THE UPGRADE IS COMPLETE.

SINCE THE UPGRADE WILL CAUSE THE SHREVEPORT DOPPLER RADAR TO BE
OUT OF SERVICE AND UNAVAILABLE FOR A PERIOD OF TIME DURING THE
DOWN TIME...THE NWS OFFICE IN SHREVEPORT WILL USE SURROUNDING RADARS
FOR COVERAGE...SUCH AS THOSE IN FORT POLK LOUISIANA...LITTLE ROCK AND
FORT SMITH ARKANSAS...AND FORT WORTH TEXAS.

&&
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Quoting bohonkweatherman:
Good Morning Largo, last time Austin had over 1 inch of rain in 1 day was 99 days ago, that should end Tuesday. Have a great day!


Good luck out there Dennis
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Quoting LargoFl:
be somewhat careful tomorrow Texas,heed your warnings..
Good Morning Largo, last time Austin had over 1 inch of rain in 1 day was 99 days ago, that should end Tuesday. Have a great day!
Member Since: July 5, 2009 Posts: 0 Comments: 1348
Looks reasonable, most stays offshore

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1069. LargoFl
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1068. LargoFl
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1067. LargoFl
Quoting TomballTXPride:






LargoFl ~

You are by far one of the best posters here.

You always post relevant weather related information, maps, and graphs.

I love it.

Keep up the good work!








Thanks I try to get the warnings out so people can prepare best they can..enjoy the rains there this week,out to help the drought a lil...
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Models backing off on rain amounts, leaves Central TX dry

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1065. pottery
Quoting AussieStorm:
My next 48hrs......


Really big fluctuation there Aussie.
Temps like those would confuse my body's thermostat big time !
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Quoting LargoFl:
Rita be careful over there mid week, nws said some spots might pick up 6-7 inches of rain..thats alot huh...


Yes, but I'll believe it when I see it
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1062. LargoFl
Quoting RitaEvac:
Looking like some showers for TX this week
Rita be careful over there mid week, nws said some spots might pick up 6-7 inches of rain..thats alot huh...
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1061. LargoFl
GFS says more showers here today..............
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Looking like some showers for TX this week
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1059. LargoFl
guess there's a game down in south florida?...
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1058. LargoFl
Quoting biff4ugo:
Impressive rain predictions. 0% for Ocala and Gainesville right next to 90% and 80% for Brooksville and Daytona Beach!
They KNOW where it is going to land!
WOW! I don't remember them being this decisive before.
yeah we will see how it goes today, was overcast here awhile ago, now skies are clearing,but its cooler than this morning with a breeze
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My next 48hrs......

Member Since: September 30, 2007 Posts: 9 Comments: 15962
Impressive rain predictions. 0% for Ocala and Gainesville right next to 90% and 80% for Brooksville and Daytona Beach!
They KNOW where it is going to land!
WOW! I don't remember them being this decisive before.
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1055. ARiot
Quoting MahFL:
Remember folks, bush fires and wild fires are part of the Earths natural cycle, they are needed. It's tough luck if your home is burnt to the ground....



That's true, but the "natural cycle" in many places has been significantly changed in many ways by man's activity.

A few things to think about:

- development brings with it invasive species that change the game

- we put out fires that help the native plants (since they evolved for those natural fires) and that leads to a built-up fuel source making fires bigger and faster

- AGW has allowed a specific type of wood beetle to breed twice a year, rather than once, turing strong stands into flame bait in the U.S.

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1054. LargoFl
hmmm now 80% lol.........
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1053. LargoFl
hmmm dunno what to believe anymore,he said 70% yesterday,got a few drops,my local guy must be drinking lol
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Quoting AussieStorm:
Why do people make such bold predictions??

Japan Earthquakes ‏@earthquakejapan
EARTHQUAKE WARNING (7.2 to 7.7) earthquake is likely within 400 kilometers of Tokyo, Japan next 24 hours.


This prediction was made 13hrs ago. If nothing happens in the next 11hrs, this person is a goof-ball.


...Why? Pretty simple, really. Eventually they will 'hit', and cash in on it.

An old stock racket version of the same maneuver went like this: The stock shop would arrange for 10,000 mailings of a news letter. For each 2,000 mailings though, they would have a unique letter go out under a different name, some projecting the markets and particular stocks this way, others that way. One of those five different versions would hit things out pretty good. They would then visit or call those 2000 marks saying "See? We're good! We're prophets! Let us invest your money and become rich! You can't miss!" They would then flush that hot and sweaty capital through whatever pump 'n dumps they had ready to roll, say "Oops! It wasn't our fault! Yada yada yada, but this next one is real good!", soak 'em again and then disappear to resurface somewhere else and run the ruse again.

So, If you run around screaming in some limited market that this month California (or wherever) is going to have a big quake and you miss, just move on to the next market, scream the same thing.... eventually you will hit and can cash in however you like ... publish a book you have already to go, lectures and talk shows, and hope to leverage your way up.
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Quoting MahFL:
Remember folks, bush fires and wild fires are part of the Earths natural cycle, they are needed. It's tough luck if your home is burnt to the ground....


Even tougher luck if you're a koala up in a tree.
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Quoting MahFL:
Remember folks, bush fires and wild fires are part of the Earths natural cycle, they are needed. It's tough luck if your home is burnt to the ground....
Wildland blazes are definitely a natural process, and people who knowingly build in thickly-wooded, fire-prone areas do have themselves at least partially to blame. But I don't know that I'd be so callous as to say, "tough luck"; after all, watching your children being devoured by wild animals used to also be "part of the Earths natural cycle"--wolves and bears and tigers gotta eat, don't you know--but I doubt that consoling a grieving parent by telling them "tough luck" would have gone over too well... ;-)
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1049. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #41
TROPICAL STORM SONAMU (T1301)
21:00 PM JST January 6 2013
===================================

SUBJECT: Category One Typhoon In South China Sea

At 12:00 PM UTC, Tropical Storm Sonamu (998 hPa) located at 6.3N 108.2E has 10 minute sustained winds of 35 knots with gusts of 50 knots. The cyclone is reported as moving south southwest slowly.

Dvorak Intensity: T2.5

Gale Force Winds
================
120 NM from the center in northwestern quadrant
90 NM from the center in southeastern quadrant

Forecast and Intensity
======================
24 HRS: 5.0N 107.8E - Tropical Depression In South China Sea
Member Since: May 24, 2006 Posts: 51 Comments: 46158
1048. HadesGodWyvern (Mod)
Darwin Tropical Cyclone Warning Center
Tropical Cyclone Advisory
TROPICAL LOW 05U
9:00 PM CST January 7 2012
=========================================

At 8:00 PM CST, Tropical Low (999 hPa) was located near 11.1S 120.9E or 780 km north of Broome has 10 minute sustained winds of 25 knots. The low is reported as moving west at 4 knots.

Dvorak Intensity: T2.0/2.0/D0.5/24 HRS

Forecast and Intensity
=======================
12 HRS: 11.7S 119.5E - 40 knots (CAT 1/Tropical Cyclone)
24 HRS: 12.0S 118.1E - 45 knots (CAT 1/Tropical Cyclone)
48 HRS: 13.1S 116.9E - 75 knots (CAT 3/Severe Tropical Cyclone)
72 HRS: 15.3S 115.3E - 95 knots (CAT 4/Severe Tropical Cyclone)

Additional Information
======================
Position extrapolated based on 0927Z microwave and 0830Z visible MTSAT image, south of Sumba Island. low level circulation center was partially exposed with slightly improved curvature. Latest IR analysis yields 0.3 curved band, DT=2.0. MET and PAT agree. Moderate northeast wind shear has limited the development rate to T0.5/day.

The environment is favorable for further development with deep moisture, upper divergence and vigorous westerly monsoonal flow to the north. Intensification is expected to return to the standard rate as the system becomes more organized and moves closer to the upper ridge axis. Tropical cyclone formation is expected late Tuesday or early Wednesday, then a steady intensification later in the week as the tropical cyclone moves further southwest.

The tropical cyclone is forecast to move closer to the Western Australia coast later in the week under the influence of an approaching upper trough, but its longer term movement is uncertain.
Member Since: May 24, 2006 Posts: 51 Comments: 46158

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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.