Skip Navigation Links weather.gov   
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
National Hurricane Center
Local forecast by
"City, St" or "ZIP"

 
Alternate Formats
   Text     |   Mobile
   Email   |   RSS XML/RSS logo
   About Alternates
Tropical Cyclones
   Arthur
   Bertha
   Cristobal
   Dolly
   Edouard
   Fay
   Seven
   Gustav
   Hanna
   Isidore
   Josephine
   Kyle
   Lili
   Fourteen
Cyclone Forecasts
   Latest Advisory
   Past Advisories
   Audio/Podcasts
   About Advisories
Marine Forecasts
   Atlantic & E Pacific
   Gridded Marine
   About Marine
Tools & Data
   Satellite | Radar
   Analysis Tools
   Aircraft Recon
   GIS Datasets
   Data Archive
Development
   Experimental
   Research
   Forecast Accuracy
Outreach & Education
   Prepare
   Storm Surge
   About Cyclones
   Cyclone Names
   Wind Scale
   Most Extreme
   Forecast Models
   Breakpoints
   Resources
   Glossary | Acronyms
   Frequent Questions
Our Organization
   About NHC
   Mission & Vision
   Staff | Q&A
   Visitors | Virtual Tour
   Library Branch
   NCEP | Newsletter
Contact Us
   Comments
Follow the National Hurricane Cent
er on Facebook Follow the National Hurricane Center on Twitter
FirstGov.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.
 
 

Tropical Cyclone Report

Tropical Storm Dolly

29 August - 4 September 2002

Lixion. A. Avila
National Hurricane Center
12 October 2002

Dolly was the first Atlantic basin tropical cyclone to develop in the deep tropics in 2002.

a. Synoptic History

Dolly developed from a tropical wave that moved off the west coast of Africa on 27 August. As the wave moved westward, ship observations indicated that the wave was accompanied by an area of low pressure and satellite images showed increasing thunderstorm activity. The system moved west and west-southwest and became a tropical depression at 1200 UTC 29 August about 550 n mi southwest of the westernmost Cape Verde Islands. The depression quickly became better organized, developing well-defined cyclonically curved convective bands and good outflow in all quadrants. It became a tropical storm by 1800 UTC on the same day and reached its peak intensity of 50 knots and a minimum pressure of 997 mb at 1200 UTC 30 August. Dolly moved toward the west and west-northwest around the periphery of a subtropical ridge for a couple of days. Thereafter, tropical cyclone curved to the northwest and then north ahead of a mid-level trough with a minor fluctuation in intensity at 0000 UTC 3 September when convection decreased. It finally became a remnant low late on 4 September when strong shear removed most of the convection, and ultimately became absorbed by the trough.

The "best track" chart of the tropical cyclone's path is given in Figure 1, with the wind and pressure histories shown in Figure 2 and Figure 3, respectively. The best track positions and intensities are listed in Table 1.

b. Meteorological Statistics

Observations in Dolly (Figure 2 and Figure 3) include satellite-based Dvorak technique intensity estimates from the Tropical Analysis and Forecast Branch (TAFB), the Satellite Analysis Branch (SAB) and the U. S. Air Force Weather Agency (AFWA). Operationally, the maximum winds in Dolly were 55 knots at 1200 UTC 30 August based on a 3.5 Dvorak classification. However, a post-analysis of visible images showed that the low level-center was not embedded completely within the deep convection. This suggested that Dolly was a weaker tropical cyclone and the maximum winds have been adjusted to 50 knots in the best track.

c. Casualty and Damage Statistics

There were no reports of damage or casualties associated with Dolly.

d. Forecast and Warning Critique

Average official track errors (with the number of cases in parentheses) for Dolly were 48 (21), 83 (19), 121 (17), 155 (15), and 240 (11) n mi for the 12, 24, 36, 48, and 72 h forecasts, respectively. These errors are slightly larger than the average official track errors for the 10-yr period 1992-2001 which are 43, 81, 115, 148, and 222 n mi respectively. However, they are smaller than nearly all of the numerical guidance models. A comparison of the official forecast track errors with selected numerical guidance is given in Table 2.

Average official intensity errors were 4, 8, 11, 14, and 15 kt for the 12, 24, 36, 48, and 72 h forecasts, respectively. For comparison, the average official intensity errors over the 10-yr period 1992-2001 are 7, 11, 14, 16, and 19 kt, respectively. Initially, Dolly was forecast to become a hurricane when it was located in the deep tropics and the environment appeared to be favorable. However, the cyclone turned northward into a shearing environment and weakened instead.



Table 1: Best track for Tropical Storm Dolly, 29 August- 4 September.
Date/Time
(UTC)
PositionPressure
(mb)
Wind Speed
(kt)
Stage
Lat.
(°N)
Lon.
(°W)
29 / 12009.531.2100730tropical depression
29 / 18009.732.2100535tropical storm
30 / 00009.733.1100240"
30 / 060010.034.5100045"
30 / 120010.336.399750"
30 / 180010.837.7100050"
31 / 000011.539.1100045"
31 / 060012.140.9100240"
31 / 120012.842.9100535"
31 / 180013.244.9100535"
01 / 000013.646.8100535"
01 / 060014.148.4100535"
01 / 120014.849.9100535"
01 / 180015.651.2100240"
02 / 000016.452.0100140"
02 / 060017.152.5100140"
02 / 120017.952.9100045"
02 / 180018.553.3100245"
03 / 000019.353.7100240"
03 / 060019.653.7100045"
03 / 120021.052.9100045"
03 / 180022.252.4100145"
04 / 000023.152.4100145"
04 / 060023.552.4100535"
04 / 120023.552.5100925tropical depression
04 / 180024.052.5100920remnant low
30 / 120010.336.399750minimum pressure


Table 2: Preliminary forecast evaluation (heterogeneous sample) for Dolly, 29 August-4 September, 2002. Forecast errors for tropical storm and hurricane stages (n mi) are followed by the number of forecasts in parentheses. Errors smaller than the NHC official forecast are shown in bold-face type.
Forecast TechniquePeriod (hours)
1224364872
CLP560 (21)110 (19)174 (17)239 (15)355 (11)
GFDI64 (21)122 (19)165 (17)230 (15)342 (11)
GFDL59 (21)109 (18)159 (16)212 (14)314 (10)
LBAR51 (21)77 (19)103 (17)137 (15)194 (11)
AVNI54 (21)96 (19)157 (17)223 (14)343 ( 7)
AVNO56 (21)87 (19)139 (17)192 (14)285 ( 6)
AEMI71 (14)145 (12)249 (11)73 ( 4)
BAMD56 (21)92 (19)134 (17)186 (15)274 (11)
BAMM49 (21)88 (19)119 (17)167 (15)261 (11)
BAMS65 (21)129 (19)193 (17)262 (15)392 (11)
NGPI60 (20)99 (18)144 (16)199 (14)297 (10)
NGPS68 (21)96 (19)131 (17)188 (15)308 (11)
UKMI64 (20)88 (18)118 (16)157 (14)243 (11)
UKM58 (10)92 ( 9)99 ( 8)118 ( 7)200 ( 5)
A98E60 (21)94 (19)134 (17)197 (15)313 (11)
A9UK52 (10)89 ( 9)141 ( 8)223 ( 7)330 ( 5)
GUNS58 (19)97 (17)130 (15)182 (13)265 (10)
GUNA55 (19)92 (17)131 (15)179 (12)205 ( 6)
OFCL48 (21)83 (19)121 (17)155 (15)240 (11)
NHC Official (1992-2001 mean)43 (2199)81 (1965)115 (1759)148 (1580)222 (1272)
*Output from these models was unavailable at time of forecast issuance.

Best track positions for Tropical Storm Dolly

Figure 1: Best track positions for Tropical Storm Dolly, 29 August - 4 September 2002.

Selected wind observations and best track maximum sustained surface wind speed curve for Tropical Storm Dolly

Figure 2: Selected wind observations and best track maximum sustained surface wind speed curve for Tropical Storm Dolly, 29 August- 4 September, 2002.

Selected pressure observations and best track minimum central pressure curve for Tropical Storm Dolly

Figure 3: Selected pressure observations and best track minimum central pressure curve for Tropical Storm Dolly, 29 August- 4 September.



Quick Navigation Links:
Tropical Cyclone Forecasts  -  Tropical Marine Forecasts  -  Data Archive
Outreach  -  Prepare  -  About Cyclones  -  About NHC  -  Contact Us

NOAA/ National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Credits
Information Quality
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities
Page last modified: Wednesday, 14-Feb-2007 13:19:19 UTC