Hurricane Dolly Forecast Verification
Written by Derek Ortt on February 21, 2009

Hurricane Dolly was a well forecast-hurricane. Both track and intensity errors were well below the long-term mean and CLIPER techniques. The main source of track error that was present was due to two source.s The first was due to disorganization near the Yucatan. This caused forecast #2 to have an initial position error of more than 40NM. The second was related to the acceleration after landfall. Track forecasts indicated a slower than observed track.

The main source of intensity error was due to forecasts weakening the hurricane too quickly after landfall. All forecasts correctly indicated Dolly reaching category 2 status.

Statements indicating Hurricane Conditions were possible and expected for the landfall area were included in the updates starting at 2100 UTC 7/21 and 0900 UTC 7/22 respectively. Statements for tropical storm conditions expected for the Cayman Islands and the Yucatan were also included with appropriate lead time.

For synoptic history, and official watches and warnings, please visit the National Hurricane Center Tropical Cyclone Report

Figure 1: Mean track and intensity errors for Hurricane Dolly. Blue represents NWHHC error, black the 10-year NHC mean, and red CLIPER/SHIFOR>

Figure 2: Dolly track forecast #1. Blue represents NWHHC forecast, red the best track.

Times when tropical storm/hurricane condition statements included in updates

7/20 1500 UTC: Tropical Storm conditions expected: Cayman Islands, Yucatan from Chetumal to Cancun
7/20 2100 UTC: Tropical Storm conditions no longer expected: Cayman Islands, south of Tulum, Mexico
7/21 0300 UTC: Tropical Storm conditions expected: Cancun to Merida, Mexico
7/21 1200 UTC: Tropical Storm conditions no longer expected: South of Cancun
7/21 1500 UTC: Tropical Storm conditions no longer expected: Cancun to Merida
7/21 2100 UTC: Hurricane Conditions possible: La Pesca, Mexico to Matagorda, Texas
7/22 0900 UTC HURRICANE CONDITIONS EXPECTED: La Pesca to Corpus Christi, Texas
7/23 1300 UTC: Hurricane Conditions no longer expected: La Pesca to Laguna Madre, Mexico
7/23 1500 UTC: Hurricane Conditions no longer possible: Corpus Christi to Matagorda
7/23 1700 UTC: Hurricane Conditions no longer expected: Matamoros, Mexico to Laguna Madre
7/23 2100 UTC: Hurricane Conditions no longer expected: Corpus Christi to Kingville, Texas
7/24 0000 UTC: Hurricane Conditions no longer expected/Tropical Storm Conditions expected: Matamoros to Alice, Texas
7/24 0000 UTC: Hurricane Conditions no longer expected: Alice to Kingville
7/24 0300 UTC Tropical Storm Conditions no longer expected: Matamoros to Alice

Click Here for individual forecast error statistics

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