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Forecast for 2008 -- more hurricanes for the Panhandle
By Philip J. Klotzbach1 and William M. Gray
From the Department of Atmospheric Science
Colorado State University
Fort Collins, Colo.
"We foresee an active Atlantic basin hurricane season."
The following forecast was issued on April 9, 2008 as a revision to a previous forecast done Decemember 2007.
|
Forecast Parameter and 1950-2000 Climatology (in parentheses) |
Issue Date |
Re-Issue Date |
|
|
Dec. 7, 2007 |
April 9, 2008 |
|
Named Storms (NS) (9.6) |
13 |
15 |
|
Named Storm Days (NSD) (49.1) |
60 |
80 |
|
Hurricanes (H) (5.9) |
7 |
8 |
|
Hurricane Days (HD) (24.5) |
30 |
40 |
|
Intense Hurricanes (IH) (2.3) |
3 |
4 |
|
Intense Hurricane Days (IHD) |
6 |
9 |
|
Accumulated Cyclone Energy (ACE) (96.1) |
115 |
150 |
|
Net Tropical Cyclone Activity (NTC) (100%) |
125 |
160 |
Estimated probability (expressed in percent) of one or more U.S. landfalling tropical storms (TS), category 1-2 hurricanes (HUR), category 3-4-5 hurricanes, total hurricanes and named storms along the entire U.S. coastline, along the Gulf Coast (region 1-4), and along the Florida Peninsula and the East Coast (Regions 5-11) for 2008. The long-term mean annual probability of one or more landfalling systems during the last 100 years is given in parentheses.
|
Coastal Region |
TS |
Cat 1-2 |
Cat 3,4,5 |
All Hurricanes |
Named Storms |
|
Entire US |
92% (79%) |
84% (68%) |
69% (52%) |
95% (84%) |
99% (97%) |
|
Gulf Coast |
76% (59%) |
59% (42%) |
44% (30%) |
77% (60%) |
94% (83%) |
|
Florida + East Coast |
67% (50%) |
60% (44%) |
45% (31%) |
78% (61%) |
93% (81%) |
Probabilities for at least one major (category 3-4-5) hurricane Landfall on each of the following coastal areas:
• Entire U.S. coastline - 69% (average for last century is 52%).
• U.S. East Coast Including Peninsula Florida - 45% (average for last century is
31%).
• Gulf Coast from the Florida Panhandle westward to Brownsville - 44% (average
for last century is 30%).
• Above-average major hurricane landfall risk in the Caribbean.
DEFINITIONS
• Accumulated Cyclone Energy - (ACE) A measure of a named storm's potential for wind and storm surge destruction
defined as the sum of the square of a named storm's maximum wind speed (in 104 knots2) for each 6-hour period of its
existence. The 1950-2000 average value of this parameter is 96.
• Hurricane - (H) A tropical cyclone with sustained low-level winds of 74 miles per hour (33 ms-1 or 64 knots) or
greater.
• Hurricane Day - (HD) A measure of hurricane activity, one unit of which occurs as four 6-hour periods during which a tropical cyclone is observed or estimated to have hurricane intensity winds.
• Intense Hurricane - (IH) A hurricane which reaches a sustained low-level wind of at least 111 mph (96 knots or 50 ms) at some point in its lifetime. This constitutes a category 3 or higher on the Saffir/Simpson scale (also termed a "major" hurricane).
• Intense Hurricane Day - (IHD) Four 6-hour periods during which a hurricane has an intensity of Saffir/Simpson category 3 or higher.
• Named Storm - (NS) A hurricane or a tropical storm.
• Named Storm Day - (NSD) As in HD but for four 6-hour periods during which a tropical cyclone is observed (or is estimated) to have attained tropical storm intensity winds.
• NTC - Net Tropical Cyclone Activity -Average seasonal percentage mean of NS, NSD, H, HD, IH, IHD. Gives overall indication of Atlantic basin seasonal hurricane activity. The 1950-2000 average value of this parameter is 100.
• Tropical Cyclone - (TC) A large-scale circular flow occurring within the tropics and subtropics which has its strongest winds at low levels; including hurricanes, tropical storms and other weaker rotating vortices.
• Tropical Storm - (TS) A tropical cyclone with maximum sustained winds between 39 (18 ms-1 or 34 knots) and 73 (32 ms-1 or 63 knots) miles per hour.
