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
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 Center on Facebook Follow the National Hurricane Center on Twitter
Subscribe the National Hurricane Center on YouTube Read the National Hurricane Center Inside the Eye blog on WordPress
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 Henri

3 - 8 September 2003

Daniel P. Brown and Miles Lawrence
National Hurricane Center
1 November 2003

Henri was a tropical storm with maximum 1-min surface winds of 50 kt in the eastern Gulf of Mexico. After weakening to a depression, it moved across central Florida, where it dumped up to ten inches of rainfall.

a. Synoptic History

Henri formed from a tropical wave that moved from Africa to the tropical Atlantic Ocean on 22 August. The wave reached the eastern Gulf of Mexico on 1 September where the northern portion became nearly stationary, while the southern portion continued westward. By 1800 UTC on 3 September, the associated convection and low-level circulation became well-enough organized about 260 n mi west of Tampa, Florida to become Tropical Depression Twelve.

The "best track" chart of the tropical cyclone's path starts on the 3 September and is plotted in Figure 1; the wind and pressure histories are plotted in Figure 2 and Figure 3, respectively. The complete best track positions and intensities are listed in Table 1.

The depression was embedded in the southern portion of a slow-moving mid-latitude trough and moved slowly eastward. The depression became a tropical storm at 0600 UTC , 5 September and the wind speed increased to its maximum value of 50 kt on 1800 UTC on that day even though there was at least 20 kt of southwesterly vertical shear affecting the circulation. The winds quickly weakened to 30 kt before Henri, preceded and accompanied by heavy rain, accelerated northeastward across north-central Florida on the 6 September. Over the southwestern North Atlantic Ocean, Henri slowed its forward speed on 7 September when it became trapped to the south of a shallow high pressure system. Strong vertical shear finally led to its dissipation when the depression lost a well-defined low-level circulation and simultaneously became involved with a frontal zone resulting in a spreading out of the wind field. The broad and disorganized extratropical low remained nearly stationary off the coast of the Carolinas for several days and moved inland over North Carolina on 12-13 September.

b. Meteorological Statistics

Wind speed estimates in Henri are based on 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), as well as flight-level and dropwindsonde observations from flights of the 53rd Weather Reconnaissance Squadron of the U. S. Air Force Reserve Command. These estimates and observations are plotted in Figure 2. Minimum central pressure data are plotted in Figure 3.

There were no ship reports of tropical storm force winds. On 5 September, a reconnaissance aircraft reported an 850-mb flight level wind speed of 46 kt at 1116 UTC, along with 997 mb surface pressure. Data buoy 42036, located in the northeastern Gulf of Mexico, reported a 10-min. mean wind speed of 45 kt with a gust to 64 kt at 1720 UTC on the same day. This buoy also reported a surface pressure of 1001.7 mb at 1750 UTC. Henri was centered about 25 n mi east-southeast of the buoy at the time of the 45-kt wind speed. Based on these reports, Henri's highest 1-min wind speed is estimated at 50 kt at 1800 UTC. Note in Figure 2 that subjective Dvorak wind speed estimates based on satellite imagery were as high as 55 to 65 kt. Based on aircraft data, as well as the buoy, Henri's maximum wind speed quickly decreased to 30 kt during the next six hours as the low level center became totally exposed. Then Henri crossed over Florida as a tropical depression.

Henri's rain affected much of Florida. There were five to ten inches of rain in portions of Charlotte County. There was generally minor freshwater flooding in two areas: from Sarasota through Lee Counties , and a small portion of southern Hernando and extreme northern Pasco County. In southern Florida and in the panhandle area, rainfall totals were generally less than two inches.

c. Casualty and Damage Statistics

There were no deaths attributed to Henri. However, a male in Lee County was injured when struck by lightning from a thunderstorm in a feeder band. Also, an indirect injury occurred when a vehicle driven by a Pinellas Park man hydro-planed into a concrete wall on Interstate 275 in Tampa. Damage from flooding was generally minor.

d. Forecast and Warning Critique

Average official track errors (with the number of cases in parentheses) for Henri were 44 (18),73 (16), 83 (14), 97 (12), 82 (8), and 124 (4) n mi for the 12, 24, 36, 48, 72, and 96 h forecasts, respectively1. These errors are lower than the average official track errors for the 10-yr period 1993-20022 (45, 81, 116, 150, 225, and 282, n mi, respectively). Henri did not last long enough to verify any 120-h forecasts.

Average official intensity errors were 5, 8, 7, 8, 8, and 3 kt for the 12, 24, 36, 48, 72, and 96 h forecasts, respectively. For comparison, the average official intensity errors over the 10-yr period 1993-2002 are 6, 10, 13, 15, 19, and 21 kt, respectively.

Table 2 lists the watches and warnings issued for Henri.

1 All forecast verifications in this report include the depression stage of the cyclone. National Hurricane Center verifications presented in these reports prior to 2003 did not include the depression stage.

2 Errors given for the 96 h periods are averages over the two-year period 2001-2002.



Table 1: Best track for Tropical Storm Henri, 3-8 September 2003.
Date/Time
(UTC)
PositionPressure
(mb)
Wind Speed
(kt)
Stage
Lat.
(°N)
Lon.
(°W)
 03 / 1800 27.4 87.7 1013 25 tropical depression
 04 / 0000 27.6 87.8 1011 25 "
 04 / 0600 27.8 87.6 1009 25 "
 04 / 1200 27.8 87.2 1010 30 "
 04 / 1800 27.8 86.3 1002 30 "
 05 / 0000 27.6 85.8 1004 30 "
 05 / 0600 27.7 85.1 1000 35 tropical storm
 05 / 1200 28.1 84.4 997 40 "
 05 / 1800 28.3 84.2 997 50 "
 06 / 0000 27.9 83.9 1002 30 tropical depression
 06 / 0600 27.7 83.5 1005 30 "
 06 / 1200 28.4 81.8 1007 25 "
 06 / 1800 29.2 80.4 1006 25 "
 07 / 0000 30.0 79.5 1006 30 "
 07 / 0600 30.5 79.2 1008 30 "
 07 / 1200 30.8 78.5 1006 30 "
 07 / 1800 31.3 77.9 1006 30 "
 08 / 0000 31.7 77.1 1006 30 "
 08 / 0600 32.1 76.5 1007 30 "
 08 / 1200 32.5 75.9 1006 30 "
 08 / 1800 32.9 75.3 1006 25 extratropical
 09 / 0000     dissipated
 05 / 1800 28.3 84.2 997 50 minimum pressure
 06/0900 27.9 82.8 1006 30 landfall near Clearwater, FL


Table 2: Watch and warning summary for Tropical Storm Henri, 3-8 September 2003.
Date/TimeActionLocation
03/2100tropical storm warning issuedEnglewood to Indian Pass, Florida 
05/0000tropical storm warning discontinuedAucilla River to Indian Pass 
06/0300tropical storm warning discontinuedSwannee River to Aucilla 
06/0900all warnings discontinued 

Best track positions for Tropical Storm Henri

Figure 1: Best track positions for Tropical Storm Henri, 3-8 September 2003.

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

Figure 2: Selected wind observations and best track maximum sustained surface wind speed curve for Tropical Storm Henri, 3-8 September 2003. Aircraft observations, when available, have been adjusted for elevation using 90%, 80%, and 80% reduction factors for observations from 700 mb, 850 mb, and 1500 ft, respectively.

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

Figure 3: Selected pressure observations and best track minimum central pressure curve for Tropical Storm Henri, 3-8 September 2003.



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: Monday, 07-Feb-2005 16:38:05 UTC