U.S. vulnerability to sea level rise
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
Reader Comments
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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.
Sea Breeze is starting to move in as well. Tops on those storms are approaching 50K
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
I noticed that Skye. I wonder what's up with that. They should be long over water by now.
They switched over to Pacific header URPN15 KNHC
there will be a strong mjo pulse right over that area!!!
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.
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.
Here it is. Wow that was sneaky...thanks nrt.
They are finding 63kt flight-level winds out of the NE in the NW quadrant.
We can't....I believe them....I guess for some reason the central pressure hasn't risen yet...but that is honestly very strange.
It's disorganized and not really interesting at all right now lol. I personally don't see it as a threat to develop.
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)
I agree with you but Noaa still calls it INVEST. Why do they do that?
Looks like the center will stay offshore. Looks to be moving almost WNW now.
They probably needed the rain in that area anyway.
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.
Heaviest convection is all offshore...raining on the fishie's.
They usually put satellite floaters on it when something is mentioned in the NHC tropical outlook but that doesn't make it an official invest.
I agree. I was questioning the severe weather threat for Tampa all day long.
Cuyutlan Radar
You can see the rain bands right on the east side of the COC that would have been the eyewall had the CDO stayed intact. No rain over land anymore.
Well, that's annoying. By the way, Andres looks like it's struggling.
Oh really what was your first clue....?
lol
Tropical Cyclone Warning Number SIX
DEPRESSION ARB01-2009
20:30 PM IST June 23 2009
==================================
Subject: Depression crossed near Diu of south Gujarat coast.
At 15:00 PM UTC, Depression ARB01-2009 over east central Arabian Sea moved further northwestwards and crossed the coast near Diu of south Gujarat coast between 1300 to 1500 PM UTC (1830-2030 IST).
The system is likely to move in a north-northwesterly direction and weaken gradually
I don't see a regular shape. It is shaped like an oval with the center far off to one side.
You like arguing with me, don't you? You said it was struggling, too.
URPN12 KNHC 231812
VORTEX DATA MESSAGE EP022009
A. 23/17:44:30Z
B. 18 deg 20 min N
104 deg 48 min W
C. 700 mb 2982 m
D. 63 kt
E. 124 deg 12 nm
F. 228 deg 49 kt
G. 127 deg 20 nm
H. EXTRAP 988 mb
I. 7 C / 3050 m
J. 15 C / 3047 m
K. 6 C / NA
L. NA
M. NA
N. 12345 / 7
O. 0.02 / 2 nm
P. AF306 0102E ANDRES OB 06
MAX FL WIND 62 KT NW QUAD 17:50:00Z
MAX OUTBOUND FL WIND 62 KT NW QUAD 17:50:00Z
SLP EXTRAP FROM 700 MB
SURFACE CENTER NOT VISIBLE DUE TO UNDERCAST
;
Lol I'm just playing around. Yes all the convection is now south of the center which is now exposed completely.
The National Weather Service in Miami has issued a
* Severe Thunderstorm Warning for...
western Palm Beach County in South Florida.
* Until 315 PM EDT
* at 218 PM EDT... National Weather Service Doppler radar indicated a
line of severe thunderstorms capable of producing nickel size
hail... and damaging winds in excess of 60 mph. These storms were
located along a line extending from 15 miles north of Canal Point
to 41 miles west of South Bay... and moving southeast at 30 mph.
* The line of storms will affect...
Canal Point...
Belle Glade...
Okeelanta...
lion country safari...
and surrounding communities.
Those flight-level winds don't quite support a 60kt system. Maybe 50 or 55kts. It has an amazing core temperature difference of 8C for a system with no central convection.
{edit} - I didn't notice the 63kt surface reading at "D." Apparently the difference in winds with height is not significant in this case due to weakening.
Sorry I take a ton of things seriously.
They're at the upper level of their planned altitude in Andres. Maybe this is the last hurra, it's clearly becoming exposed. Those higher winds up high tend to fall to the surface in the weakening before it really lets up.
weakening flag on
----- Current Analysis -----
Date : 23 JUN 2009 Time : 171500 UTC
Lat : 18:14:15 N Lon : 104:42:00 W
CI# /Pressure/ Vmax
3.8 / 991.6mb/ 61.0kt
Final T# Adj T# Raw T#
(3hr avg)
3.3 3.1 2.7
Latitude bias adjustment to MSLP : +1.8mb
Center Temp : -23.7C Cloud Region Temp : -39.9C
Scene Type : CURVED BAND with 0.42 ARC in LT GRAY
Maximum CURVED BAND with 0.48 ARC in LT GRAY
at Lat: 18:13:47 N Lon: 104:54:00 W
Positioning Method : FORECAST INTERPOLATION
Ocean Basin : EAST PACIFIC
Dvorak CI > MSLP Conversion Used : ATLANTIC
Tno/CI Rules : Constraint Limits : 0.7T/6hr
Weakening Flag : ON
Rapid Dissipation Flag : FLAG
Is that front still sliding southward? If so, there might be a chance for some of the convection to head this way. No?
UW-CIMSS Experimental Vertical Shear and TC Intensity Trend Estimates
Current Conditions (from TPC) :
Latitude : 18:17:30 N
Longitude : 104:48:08 W
Intensity (MSLP) : 990.5 hPa
Max Pot Int (MPI,from Emanuel) : 914.0 hPa
MPI differential (MSLP-MPI) : 76.5 hPa
CIMSS Vertical Shear Magnitude : 7.5 m/s
Direction : 19.3 deg
Outlook for TC Intensification Based on Current
Env. Shear Values and MPI Differential
Forecast Interval : 6hr 12hr 18hr 24hr
F F F F
Legend : VF-Very Favorable F-Favorable N-Neutral
U-Unfavorable VU-Very Unfavorable
-- Mean Intensity Trend (negative indicates TC deepening) --
6hr 12hr 18hr 24hr
VF <-3.0mb/ 6hr <-6.0mb/12hr <-9.0mb/18hr <-12.0mb/24hr
F -3.0 - -1.0 -6.0 - -2.0 -9.0 - -3.0 -12.0 - -4.0
N -1.0 - +1.0 -2.0 - +2.0 -3.0 - +3.0 -4.0 - +4.0
U +1.0 - +3.0 +2.0 - +6.0 +3.0 - +9.0 +4.0 -+12.0
VU >+3.0 >+6.0 >+9.0 >+12.0
Not sure where they got the 63kt surface. I did not see any SFMR readings that high, but it could be an "unreported" SFMR reading since they only transmit a peak average 10 second SFMR reading every 30 seconds.
http://www.globalresearch.ca/index.php?context=va&aid=10783
the earth goes through ~30 year cycles and we are in the 10th year of a 30 year cooling cycle.
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