HURRICANE IRIS 1995

Hurricane Iris 1995

Preliminary Report
Hurricane Iris
22 August - 07 September 1995


1995 PRELIMINARY REPORTS

Hurricane Allison (1)
Tropical Storm Barry (TS)
Tropical Storm Chantal (TS)
Tropical Storm Dean (TS)
Hurricane Erin (2)
Hurricane Felix (4)
Tropical Storm Gabrielle (TS)
Hurricane Humberto (2)
Hurricane Iris (2)
Tropical Storm Jerry (TS)
Tropical Storm Karen (TS)
Hurricane Luis (4)
Hurricane Marilyn (3)

Hurricane Noel (1)
Hurricane Opal (4)
Tropical Storm Pablo (TS)
Hurricane Roxanne (3)
Tropical Storm Sebastien (TS)
Hurricane Tanya (1)



Iris formed from the first of four consecutive tropical waves to generate tropical cyclones (Iris, Humberto, Karen, and Luis) on their generally westward trek across the tropical eastern Atlantic Ocean. Iris' evolution was greatly influenced by two of those systems, Humberto and Karen.

 

a. Synoptic History

The wave associated with the formation of Iris crossed the coast of Africa and began moving over the Atlantic Ocean on August 16th. Surface analyses showed a closed circulation around a 1009 mb pressure center located just south of Dakar. A day later, the circulation was evident in surface observations and satellite pictures near the Cape Verde Islands. Associated deep convection diminished on the 18th and 19th, but then gradually redeveloped. Dvorak technique T-numbers of 1.0 were assigned by the NHC Tropical Analysis and Forecast Branch (TAFB; TSAF in figures) on the 21st and both the TAFB and NESDIS Synoptic Analysis Branch indicated T-2.0 on the 22nd. From the satellite data it is estimated that the system became the 10th Atlantic tropical depression of the season at 1200 UTC on the 22nd, when located about 600 nautical miles to the east of the Lesser Antilles. It became Tropical Storm Iris six hours later.

The cyclone took a jog to the northwest on the 23rd and quickly strengthened. The first reconnaissance flight into Iris took place that evening and found the system to be stronger than operational estimates based on satellite pictures. The aircraft encountered 106 mph 10-second winds at a flight level of about 500 m, and a central pressure of 991 mb was reported. From this data, Iris is analyzed as a hurricane at 1800 UTC on the 23rd.

Iris moved toward the west-southwest at about 12 mph on the 24th and 25th. The change in heading was probably a consequence of a Fujiwhara interaction between Iris and Humberto located about 750 nautical miles to the east--Humberto had developed from a depression on the 22nd to a 109-mph hurricane by late on the 24th.

On the 25th, Iris neared the Lesser Antilles. An upper-level cold low was centered then to the north of Puerto Rico. Westerly vertical wind shear occurred, separating deep convection from the low-level cloud center, disrupting the circulation, and slowing the general westward progress of the cyclone. Iris weakened back to tropical storm strength. Reconnaissance aircraft and radar data indicate a reformation of the center to the east of the former position while the system meandered for about a day before moving into the islands.

Steering currents ahead of a trough to the northwest then turned Iris generally toward the north-northwest on the 27th. On this track, Iris moved up the chain of Leeward Islands and strengthened as the shear decreased. Late on the 28th, Iris regained hurricane status over the south-central Atlantic.

Iris began a Fujiwhara interaction on the 30th, with Tropical Storm Karen to its southeast. The interaction swept the weaker Karen on a spiral path around, and then into, Iris where it was absorbed on September 3rd. The interaction could have contributed to Iris' erratic motion during this period.

An eye appeared intermittently and the intensity of Iris fluctuated from August 29th through September 2nd. Iris reached its peak intensity of 109 mph several hundred miles to the southeast of Bermuda on the 1st. Iris then weakened, temporarily, in an environment of shear and relatively cool water. It dropped below hurricane strength and became extratropical while accelerating northeastward well to the southeast of Newfoundland on the 4th. It then turned eastward and deepened. The pressure fell from around 1000 mb to near 957 mb in about 48 hours. On the 7th, Iris battered western Europe as a powerful extratropical storm with sustained wind speeds near 75 mph.


b. Meteorological Statistics

The ship Pallas Athena reported 39-46 mph winds at 1200 UTC on September 1 while located about 100 nautical miles to the south-southeast of the center of Iris. This was the only ship report of wind speeds 39 mph or greater received by the NHC for the tropical cyclone phase of Iris.

The only available observation of sustained tropical storm force winds in Caribbean islands came from Desirade (just east of Guadeloupe) where a 52 mph (2-min) wind and 62 mph gust occurred. Highest reported gusts elsewhere reached 56 mph at Martinique, 46 mph at Antigua, 43 mph at Dominica, and 41 mph at St. Kitts. The lowest pressure reported from the northeastern Caribbean area was 999 mb at Antigua.


1. Rainfall Data

The primary meteorological event caused by Iris in the Caribbean islands was heavy rain. The totals were particularly large in Martinique where Ducos (La Manzo) had 17.72 inches for the event, with 16.18 inches falling in 24 hours. Other peak rainfall rates in Martinique included 1.89 inches in 30 minutes, 3.01 inches in 1 hour and 4.61 inches in 2 hours at Trois Ilets, Vauclin, and Ducos, respectively. An average of 6 inches of rain fell on Antigua.


c. Casualty and Damage Statistics

There were 5 deaths attributed to Iris; 4 in Martinique and 1 in Guadeloupe.

Few damage reports have been received at the NHC. There was extensive flooding in low-lying areas and destruction of banana trees on Antigua. Similar damage likely occurred on neighboring islands.


Maximum Sustained Winds For Hurricane Iris
22 August - 07 September, 1995

Date/Time
(UTC)
Position Pressure
(mb)
Wind Speed
(mph)
Stage
Lat. (°N) Lon. (°W)
01/0600 25.5 58.8 965 110 Category 2 Hurricane


Minimum Pressure For Hurricane Iris
22 August - 07 September, 1995

Date/Time
(UTC)
Position Pressure
(mb)
Wind Speed
(mph)
Stage
Lat. (°N) Lon. (°W)
07/0000 48.4 8.7 957 75 Extratropical Storm


Landfall for Hurricane Iris
22 August - 07 September, 1995
Date/Time
(UTC)
Pressure
(mb)
Wind Speed
(mph)
Stage Landfall
27/1800 995 60 Tropical Storm Montserrat,
Antigua
27/2300 993 65 Tropical Storm Barbuda