U.S. vulnerability to sea level rise

By: Dr. Jeff Masters , 4:04 PM GMT on June 23, 2009

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In the last century, sea level rose 5 - 6 inches (13 - 15 cm) more than the global average of 7 inches (18 cm) along the U.S. Mid-Atlantic and Gulf Coasts, because coastal lands there are sinking. Over 50% of the U.S. coastline is vulnerable or highly vulnerable to sea level rise, according to the Coastal Vulnerability Index (CVI) developed by the United States Geological Survey (USGS). In the U.S., relative sea level rise (the combined effects of global sea level rise plus the fact the land is sinking) is highest along the Mississippi River Delta in Louisiana, where relative sea level rises of 3.2 ft (.98 meters) have been observed during the 20th century. This is one of the highest relative sea level rises in the world. According to the NOAA Tides and Currents sea level rise interactive tool, the U.S. tide gauges that have shown the highest rates of sea level rise over the past century are at Grand Island, LA (1.8 ft rise since 1947), Galveston, TX (1.1 ft since 1957), and Chesapeake Bay, VA (0.6 feet since 1975). Alaska and some areas along the Pacific Northwest coast are at low risk of sea level rise, because the relative sea level is actually falling at present. Land in these regions is rising as it recovers from removal of the weight of the great ice sheets that covered much of North America during the last Ice Age. For example, relative sea level at Kodiak Island, Alaska has fallen by 1.1 feet since 1975, despite the fact global sea level has been increasing.


Figure 1. Twentieth century annual relative sea-level rise rates in mm/year along the U.S. coast. The higher rates for Louisiana (9.85 millimeters [mm] per year, about 3.3 ft/century) and the mid-Atlantic region (1.75 to 4.42 mm per year, 0.6 - 1.4 ft/century) are due to land subsidence. Sea level is stable or dropping relative to the land in the Pacific Northwest, as indicated by the negative values, where the land is tectonically active or rebounding upward in response to the melting of ice sheets since the last Ice Age. Image credit: Coastal Sensitivity to Sea-Level Rise: A Focus on the Mid-Atlantic Region (data from Zervas, 2001).

U.S. Coastal Vulnerability
The Coastal Vulnerability Index (CVI) takes into account six factors:

1) The geology of the coast. Barrier islands, river deltas, and marshes are the most vulnerable to erosion and sea level rise, while steep, rocky cliff shores are the least. Sheltered bays like Galveston Bay and Tampa Bay are less vulnerable than the exposed coasts. (Note, however, that hurricane storm surges are typically higher in sheltered bays, at least for slow-moving storms).

2) How steep the land near the coast is. Gently sloping lands are the most vulnerable. In the Gulf Coast region, the slope variable has the highest risk ranking along the Louisiana coast, the Texas coast north of Corpus Christi, and the southwest Florida coast.

3) The local rate of sea level rise. The sea level is rising faster along the western Gulf of Mexico than the eastern Gulf. The highest rates of sea-level rise in the Gulf of Mexico (and in the United States) are in the Mississippi delta region (10 mm/yr, or 1 inch/2.5 years).

4) The amount of shoreline erosion going on. Most of the U.S. coast is moderately or severely eroding, and very few areas are gaining (Figure 2).

5) The mean tidal range. Shores that have a large difference between low and high tide are less likely to get a significant storm tide--the height above mean sea level of the sum of the storm surge plus the tide. For example, in a region like Maine, which has a 12 ft range between low and high tide, a storm having a 9 ft storm surge will have a storm tide below local high tide for a quarter of a tidal cycle. Shores with a very narrow tidal range (e.g., the 2 ft tidal range common along the Texas and Louisiana Gulf Coast) will get a storm tide of 8 - 10 feet with the 9 ft storm surge in the above example. Shorelines with a narrow tidal range always get high storm tides regardless of when the storm surge hits.

6) How high the waves at shore are. Obviously, shores that experience higher wave heights are at greater risk. In the Gulf of Mexico, wave energy is highest along sections of the Texas coast and on the southern tip of the Mississippi delta.

Figure 2. Shoreline change around the United States based on surveys over the past century. All 30 coastal states are experiencing overall erosion due to natural processes (e.g., storms, sea-level rise) and human activity. If the shoreline is uncolored, no data was available. Image credit: USGS, 1985, and taken from Coastal Sensitivity to Sea-Level Rise: A Focus on the Mid-Atlantic Region).

The Coastal Vulnerability Index (CVI) web page gives detailed maps of each section of the U.S. coast, along with specific reasons why each portion of the coast was assigned the ranking it got. A brief summary:

The Gulf Coast
The Gulf Coast has 55% of its length in the "very high" or "high" vulnerability range. Fully 41% of the coast falls in the "very high" range, far more than the 28% in that category along the Pacific coast and 23% along the Atlantic coast. The region around New Orleans is the most vulnerable region of the entire U.S. coast. The Florida Panhandle, as well as the West Florida coast, are at low to moderate risk because the land is not sinking much, wave heights are lower, and the slope of the land is relatively steep near the coast. The Texas coast is considered to be at a high to very high risk because of the relatively high mean wave height, sinking land, and shallow coastal slope.

The East Coast
The East Coast has 50% of its length in the "very high" or "high" vulnerability range. The highest vulnerability areas are typically high-energy coastlines where the regional coastal slope is low and where the major landform type is a barrier island. A significant exception to this is found in the lower Chesapeake Bay. Here, the low coastal slope, vulnerable landform type (salt marsh) and high rate of relative sea-level rise combine for a high CVI value. The coastline of northern New England, particularly Maine, shows a relatively low vulnerability to future sea-level rise. This is primarily due to the steep coastal slopes and rocky shoreline characteristic of the region, as well as the large tidal range.

The Pacific Coast
The Pacific Coast has 50% of its length in the "very high" or "high" vulnerability range. Areas of very high vulnerability include the San Francisco - Monterey Bay coast and in southern California from San Luis Obispo to San Diego, where the coast is most highly populated. The highest vulnerability areas are typically lower-lying beach areas. The low risk, least vulnerable areas generally occur at rocky headlands along cliffed coasts where the coastal slope is steep, relative sea-level is falling, tide range is large, and wave energy is lower. Examples of these areas are the northern coast of Washington, Monterey, and Cape Mendocino, California.


Figure 3. The Coast Vulnerability Index (CVI) for the U.S.

References
Coastal Sensitivity to Sea-Level Rise: A Focus on the Mid-Atlantic Region.

National Assessment of Coastal Vulnerability to Sea-Level Rise: Preliminary Results for the U.S. Gulf of Mexico Coast (USGS, 2000).

Jeff Masters

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127. IKE
Quoting Levi32:
Dvorak agrees with weakening based on satellite presentation:





Heaviest convection is all offshore...raining on the fishie's.
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Quoting HadesGodWyvern:
770
TCNA21 RJTD 231800
CCAA 23180 47644 NANGKA(0904) 05125 11231 14244 230// 93111=

18:00 PM UTC June 23
TS NANGKA
12.5N 123.1E
Dvorak Intensity: T3.0

---
It's strengthening overland.. (gasp)


They usually do in the central Philippines....seems unnatural doesn't it. I guess the central Philippines are the equivalent of the Bahamas. They seldom significantly weaken a tropical cyclone.
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125. IKE
Quoting Levi32:
105. IKE 5:58 PM GMT on June 23, 2009
PRELIMINARY DATA FROM THE AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT INDICATE THAT THE MAXIMUM SUSTAINED WINDS REMAIN NEAR 70
MPH...110 KM/HR...WITH HIGHER GUSTS. ANDRES COULD BECOME A
HURRICANE DURING THE NEXT 12 HOURS...HOWEVER WEAKENING IS EXPECTED
TO BEGIN ON WEDNESDAY.


That's really weird.....THIS does not look like a border-line hurricane. It's losing all of its central convection. You can see the low-level center now. I really don't think it's anymore than a 45-50kt TS now, and weakening steadily.



Looks like the center will stay offshore. Looks to be moving almost WNW now.

They probably needed the rain in that area anyway.
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Dvorak agrees with weakening based on satellite presentation:



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123. WAHA
Quoting Levi32:


It's disorganized and not really interesting at all right now lol. I personally don't see it as a threat to develop.

I agree with you but Noaa still calls it INVEST. Why do they do that?
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122. HadesGodWyvern (Mod)
770
TCNA21 RJTD 231800
CCAA 23180 47644 NANGKA(0904) 05125 11231 14244 230// 93111=

18:00 PM UTC June 23
TS NANGKA
12.5N 123.1E
Dvorak Intensity: T3.0

---
It's strengthening overland.. (gasp)
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Quoting WAHA:
This is ridiculous, you forgot the storm in the gulf of mexico!


It's disorganized and not really interesting at all right now lol. I personally don't see it as a threat to develop.
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119. WAHA
This is ridiculous, you forgot the storm in the gulf of mexico!
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Quoting hurricane2009:


but how can we second guess the recon info?


We can't....I believe them....I guess for some reason the central pressure hasn't risen yet...but that is honestly very strange.
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Quoting nrtiwlnvragn:


They switched over to Pacific header URPN15 KNHC


Here it is. Wow that was sneaky...thanks nrt.

They are finding 63kt flight-level winds out of the NE in the NW quadrant.
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GFS is forecasting a Cape Verde system
DONT RIght this off, this is almost the exact same time last year that the GFS forecasted Bertha to form, 2 weeks in advance.
Watch it.
Member Since: July 8, 2005 Posts: 259 Comments: 23572
113. WAHA
I am switching over to tropics chat. If you want to see me just go over to there.
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105. IKE 5:58 PM GMT on June 23, 2009
PRELIMINARY DATA FROM THE AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT INDICATE THAT THE MAXIMUM SUSTAINED WINDS REMAIN NEAR 70
MPH...110 KM/HR...WITH HIGHER GUSTS. ANDRES COULD BECOME A
HURRICANE DURING THE NEXT 12 HOURS...HOWEVER WEAKENING IS EXPECTED
TO BEGIN ON WEDNESDAY.


That's really weird.....THIS does not look like a border-line hurricane. It's losing all of its central convection. You can see the low-level center now. I really don't think it's anymore than a 45-50kt TS now, and weakening steadily.

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Quoting Weather456:
For those who think the GFS is joking with the cape verde system, look at the conditions between next Monday and next Friday.



there will be a strong mjo pulse right over that area!!!
Member Since: October 5, 2007 Posts: 20 Comments: 4970
110. WAHA
Is anyone still remembering about the storm in the Gulf o' mexico?
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108. IKE
It's still a TS w/an exposed center.
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Quoting Skyepony:
Data from recon stopped a few hours ago as they were crossing over MX on the way to Andres.


They switched over to Pacific header URPN15 KNHC
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Quoting Skyepony:
Data from recon stopped a few hours ago as they were crossing over MX on the way to Andres.


I noticed that Skye. I wonder what's up with that. They should be long over water by now.
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105. IKE
BULLETIN
TROPICAL STORM ANDRES INTERMEDIATE ADVISORY NUMBER 8A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP022009
1100 AM PDT TUE JUN 23 2009

...ANDRES STILL A TROPICAL STORM...

A HURRICANE WARNING REMAINS IN EFFECT FOR THE SOUTHWESTERN COAST OF
MEXICO FROM PUNTO SAN TELMO TO CABO CORRIENTES. A HURRICANE WARNING
MEANS THAT HURRICANE CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE
WARNING AREA WITHIN 24 HOURS. PREPARATIONS TO PROTECT LIFE AND
PROPERTY SHOULD BE RUSHED TO COMPLETION.

A TROPICAL STORM WARNING REMAINS IN EFFECT FROM LAZARO CARDENAS TO
PUNTO SAN TELMO.

INTERESTS ELSEWHERE ALONG THE SOUTHWESTERN COAST OF MEXICO AND THE
SOUTHERN BAJA PENINSULA SHOULD MONITOR THE PROGRESS OF ANDRES.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE OF THE UNITED
STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL
METEOROLOGICAL SERVICE.

AT 1100 AM PDT...1800 UTC...THE CENTER OF TROPICAL STORM ANDRES WAS
LOCATED NEAR LATITUDE 18.4 NORTH...LONGITUDE 104.8 WEST OR ABOUT 55
MILES...85 KM...SOUTH-SOUTHWEST OF MANZANILLO MEXICO.

ANDRES IS MOVING TOWARD THE NORTHWEST NEAR 12 MPH...19 KM/HR...AND
THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS FOLLOWED
BY A TURN TOWARD THE WEST-NORTHWEST. ON THE FORECAST TRACK...
ANDRES SHOULD PASS VERY CLOSE TO...OR OVER...THE SOUTHWESTERN COAST
OF MEXICO WITHIN THE WARNING AREA TODAY.

PRELIMINARY DATA FROM THE AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT INDICATE THAT THE MAXIMUM SUSTAINED WINDS REMAIN NEAR 70
MPH...110 KM/HR...WITH HIGHER GUSTS. ANDRES COULD BECOME A
HURRICANE DURING THE NEXT 12 HOURS...HOWEVER WEAKENING IS EXPECTED
TO BEGIN ON WEDNESDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM
FROM THE CENTER.

THE LATEST MINIMUM CENTRAL PRESSURE REPORTED BY RECONNAISSANCE
AIRCRAFT WAS 988 MB...29.18 INCHES.

ANDRES IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 3 TO 6
INCHES OVER PORTIONS OF WEST-CENTRAL MEXICO...WITH POSSIBLE
ISOLATED MAXIMUM AMOUNTS OF 8 INCHES.

COASTAL STORM SURGE FLOODING OF 1 TO 3 FEET ABOVE NORMAL TIDE
LEVELS...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...ARE
POSSIBLE IN THE WARNING AREA.

...SUMMARY OF 1100 AM PDT INFORMATION...
LOCATION...18.4N 104.8W
MAXIMUM SUSTAINED WINDS...70 MPH
PRESENT MOVEMENT...NORTHWEST OR 315 DEGREES AT 12 MPH
MINIMUM CENTRAL PRESSURE...988 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
200 PM PDT.

$$
FORECASTER BROWN

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104. Skyepony (Mod)
Data from recon stopped a few hours ago as they were crossing over MX on the way to Andres.
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I am not sure, but I think the severe weather threat has passed for most of west central Florida. All of is is staying inland and to the south... I'm hoping we will at least get some rain in the Tampa Bay area to kill the heat. It's near 100 in a few spots.
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Quoting Ossqss:
Poppin has started over FL.

I will ask again,,,,,,, Is the GFS having difficulty due to the transition to El Nino?



Sea Breeze is starting to move in as well. Tops on those storms are approaching 50K
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101. SLU
A Cape Verde system this early is not in keeping with the type of season that is predicted for this year. Pre-August named storm days east of 60W are indicative of a very active season which is not going to happen this year as far as I can tell. The GFS has been poor at initialising systems this year so I won't lean towards a late-June CATL cyclone this year. The GFS also predicted a similar Cape Verde system last week and when the time came there wasn't even an identifiable cloudmass to trace across the Atlantic.

Out of respect for the GFS, the conditions are expected to get rather favourable for late-June so we may very well see a couple of healthy waves in that area by next week.
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Quoting OSUWXGUY:
Levi32: See the orange starting to pop out in the central Atlantic in 10-15 days? That represents downward motion and that's what we're going to start seeing more of in that area as the season progresses. Cape Verde storms and storms forming in the MDR (Main Development Region) region will be low in number this year


Hey Levi- Not that I don't agree that Cape Verde storms will struggle this year (compared to recent post 1995 year average)... But I would like to hear your reasoning for increased subsidence for the season???


It's a natural byproduct of El Nino episodes, especially reactive ones where the MJO can play a big role. With El Nino you get increased upward motion in the eastern Pacific which we have been seeing lately, and downward motion (sinking air) in the western Pacific and Indian Ocean. As El Nino matures, the atmospheric patterns will fall into place and the large area of upward motion over the entire Atlantic will shrink to a more normal size over the central and eastern Pacific and sometimes the Caribbean. This will setup another region of downward motion in the central/eastern Atlantic that is more typical of an El Nino pattern. If you look at the map below, it looks logical based on geographical location alone. The pattern "Orange, green, orange, green"

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India Meteorological Department
Tropical Cyclone Warning Number FIVE
DEPRESSION ARB01-2009
17:30 PM IST June 23 2009
==================================

At 12:00 PM UTC, Depression ARB01-2009 over east central Arabian Sea moved northwestwards and lays centered near 20.5N 71.5E, or close to south Gujarat and Diu coast near Diu.

3 minute sustained winds near the center is 25 knots with a central pressure of 998 hPa. The state of the sea is rough to very rough around the system's center.

Satellite imagery indicates organization of convection during the past 12 hours. The dvorak intensity of the system is T1.5. Associated broken low/medium clouds with embedded intense to very intense convection over Arabian Sea north of 17.5N and 65.5E - 72.0E southwest of Saurstra and Kutchh.

Vertical wind shear of horizontal wind over the region is moderate (around 15-20 knots). Sea surface temperature is 0.5 to 1.0C above normal. The system lies embedded in the southwesterly flow in lower and middle levels. The upper tropospheric ridge roughly runs along 22.0N. A trough in the upper troposheric westerlies roughly run along 65.0E to the north of 20.0N

Considering all the above, the system is likely to move in a north-northeasterly direction and cross south Gujarat coast near Diu within a few hours and weaken gradually.
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Quoting Levi32:
Good morning all.

Tropical Tidbit for Tuesday June 23 with Video


Very well done, young man! :)
Member Since: August 26, 2006 Posts: 10 Comments: 3617
Japan Meteorological Agency
Tropical Cyclone Advisory #8
TROPICAL STORM NANGKA (T0904)
0:00 AM JST June 24 2009
===================================

Subject: Category One Typhoon Overland The Philippines

At 15:00 PM UTC, Tropical Storm Nangka (994 hPa) located at 12.3N 123.7E has 10 minute sustained winds of 40 knots with gusts of 60 knots. The storm is reported as moving west at 9 knots.

Gale-Force Winds
================
150 NM from the center

Dvorak Intensity:

Forecast and Intensity
=====================
24 HRS: 15.0N 120.3E - 40 knots (Tropical Storm/CAT 1)
45 HRS: 17.4N 119.9E - 45 knots (Tropical Storm/CAT 1)
69 HRS: 20.3N 119.1E - 45 knots (Tropical Storm/CAT 1)
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Philippines Atmospherical Geophysical Astronomical Services and Administration

Tropical Storm "FERIA" has crossed Northern Samar and is now in the vicinity of Masbate.

Tropical Cyclone Bulletin #4
===========================
At 11:00 PM PhST, Tropical Storm Feria (Nangka) located at 12.5°N 123.6°E or in the vicinity of Masbate has 10 minutes sustained winds of 75 km/h (40 knots) with gusts of 90 km/h (50 knots).

Signal Warnings
===============

Signal Warning #2 (60-100 kph winds)

Luzon Region
-----------
1.Masbate
2.Ticao Island
3.Sorsogon
4.Albay
5.Camarines Provinces
6.Catanduanes
7.Marinduque
8.Romblon
9.Burias Island
10.Southern Quezon
11.Mindoro Provinces
12.Lubang Is.
13Batangas
14..Laguna
15.Cavite
16.Bataan
17.Rizal
18.Metro Manila

Vasayas Region
-------------
1.Samar Provinces
2.Northern Leyte
3.Camotes Is.
4.Biliran Island
5.Northern Iloilo
6.Northern Negros
7.Northern Cebu
8.Aklan
9.Capiz

Mindanao Region
----------------
1.None

Signal Warning #1 (30-60 kph winds)

Luzon Region
-----------
1.Northern Quezon
2.Polilio Island
3.Calamian group
4.Cuyo Island
5.Bulacan
6.Pampanga
7.Zambales
8.Tarlac
9.Nueva Ecija
10.1Aurora
11.Pangasinan

Visayas Region
-------------
1.Southern Leyte
2.Bohol
3.Rest of Cebu
4.Rest of Negros
5.Guimaras
6.Southern Iloilo
7.Antique
8.Siquijor

Mindanao Region
----------------
1.Surigao del Norte
2.Siargao Island
3.Dinagat Island
4.Camiguin

Additional Information
========================
Residents living in low lying,mountainous and coastal areas under storm warning signals #2 and 1 are alerted against possible flashloods, landslides and storm surges.

The public and the disaster coordinating councils concerned are advised to take appropriate actions and watch for the next bulletin to be issued at 5 A.M. tomorrow.
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Levi32: See the orange starting to pop out in the central Atlantic in 10-15 days? That represents downward motion and that's what we're going to start seeing more of in that area as the season progresses. Cape Verde storms and storms forming in the MDR (Main Development Region) region will be low in number this year


Hey Levi- Not that I don't agree that Cape Verde storms will struggle this year (compared to recent post 1995 year average)... But I would like to hear your reasoning for increased subsidence for the season???
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94. WAHA
Quoting Levi32:


No, disturbances and areas of low pressure within the ITCZ (intertropical convergence zone) can move through Africa from the Indian Ocean, but tropical waves only form under the special conditions over Africa, which is why they have "African" in their name. Africa is the only continent that has a large land mass in the middle of the tropics that always has the ITCZ passing through it.

I knew it! It can't last that long, but I do reallize that a hurricane called John in the pacific came from a wave from Africa, and traveled to the Western pacific! Once I learned that I was shocked.
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Quoting WAHA:

Can waves come from the Indian ocean? I never saw this before.


No, disturbances and areas of low pressure within the ITCZ (intertropical convergence zone) can move through Africa from the Indian Ocean, but tropical waves only form under the special conditions over Africa, which is why they have "African" in their name. Africa is the only continent that has a large land mass in the middle of the tropics that always has the ITCZ passing through it. The instability enhanced by the African easterly jet and friction over land cause waves to form in the easterly flow south of the subtropical high, and that's how the tropical waves form.
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92. WAHA
Quoting Levi32:


The tropical wave that helped spawn Andres came from Africa. So did the wave that is affecting the windward islands that 456 mentioned. They're called African Easterly Waves. As their name implies they originate over Africa and travel from the east.

Can waves come from the Indian ocean? I never saw this before.
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91. WAHA
Quoting Levi32:


Actually that updates every 3 hours but products like this update every hour.

That, is impressive. I just wish that was with NOAA.
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Quoting WAHA:

So they do last that long? I don't pay very much attention to Africa, do I?


The tropical wave that helped spawn Andres came from Africa. So did the wave that is affecting the windward islands that 456 mentioned. They're called African Easterly Waves. As their name implies they originate over Africa and travel from the east.
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Quoting Levi32:


Try This =)


Actually that updates every 3 hours but products like this update every hour.
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88. WAHA
Quoting Levi32:


It's not the thing over Sudan...it's too far away to reach the Atlantic in 2 days. Also African waves do last that long. They form over Africa and they can last all the way to the eastern Pacific.

So they do last that long? I don't pay very much attention to Africa, do I?
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Quoting WAHA:

Well I wouldn't know that well. Meteostat imagery doesn't give images that are close enough together in time. Instead of once every 30 minutes, it's once every six hours. It's so annoying!


Try This =)
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Poppin has started over FL.

I will ask again,,,,,,, Is the GFS having difficulty due to the transition to El Nino?

Member Since: June 12, 2005 Posts: 6 Comments: 8185
he only miss forecast of the gfs model this year that I can recall was the Western Caribbean storm two or three weeks ago, GFS still one of the more reliable models available, to me is like 24-48 hours ahead of the other global dynamical models.

Hey the result of those models are the outcome of the data entered by Humans. Never when coming down to weather will be 100% accurate. The one's that believe that doesn't know what weather is about.
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84. WAHA
Quoting Levi32:


It's not the thing over Sudan...it's too far away to reach the Atlantic in 2 days. Also African waves do last that long. They form over Africa and they can last all the way to the eastern Pacific.

Well I wouldn't know that well. Meteostat imagery doesn't give images that are close enough together in time. Instead of once every 30 minutes, it's once every six hours. It's so annoying!
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Quoting WAHA:

You see, that's what I was thinking. There's no way a wave like that can last that long. After all, it is still overland.


It's not the thing over Sudan...it's too far away to reach the Atlantic in 2 days. Also African waves do last that long. They form over Africa and they can last all the way to the eastern Pacific.
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82. WAHA
Quoting Drakoen:
What the GFS is forecasting is garbage. The GFS has had a poor cyclogenesis record this year and none of the reliable computer forecast models show development.

You see, that's what I was thinking. There's no way a wave like that can last that long. After all, it is still overland.
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The GFS is showing a chance at what could happen with upper-level conditions becoming favorable in that area of the ocean for the first time this season. It may or may not turn into something worth watching.

Here's the MJO. See the orange starting to pop out in the central Atlantic in 10-15 days? That represents downward motion and that's what we're going to start seeing more of in that area as the season progresses. Cape Verde storms and storms forming in the MDR (Main Development Region) region will be low in number this year.

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..its trending west too.

Im only happy when it rains.....
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456. I was looking at the GFS shear forescast last night and will be the first time this year that the CA have conditions that really can allow something to develops.
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What the GFS is forecasting is garbage. The GFS has had a poor cyclogenesis record this year and none of the reliable computer forecast models show development.
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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.