Fran was a Cape Verde hurricane
that moved across the Atlantic during the peak of the
hurricane season.
It made landfall on the North Carolina coast as a category three
hurricane on the Saffir/Simpson Hurricane Scale,
resulting in significant storm surge
flooding on the North Carolina coast, widespread wind damage over North Carolina
and Virginia, and extensive flooding from the Carolinas to Pennsylvania.
a. Synoptic History
Hurricane Fran formed from a tropical wave
that emerged from the west coast of Africa on 22 August. Deep convection associated with the wave
was organized in a banding-type pattern and animation of satellite images suggested a cyclonic circulation.
Ship reports soon confirmed that the circulation was on the surface. The post-analysis
"best track" in Figure 1 (86K GIF)
shows that the system became a tropical depression just
southeast of the Cape Verde Islands at 1200 UTC 23 August. Best track position,
central pressure and maximum one-minute sustained wind speed are listed for every six
hours in Table 1.
The tropical depression moved westward near 15 knots for the next few days without
significant development. This lack of development may be attributed, in part, to
disrupted low-level inflow due to the large and powerful Hurricane Edouard
which was centered about 750 n mi to the west-northwest.
Satellite intensity estimates suggest that the depression became
Tropical Storm Fran at 1200 UTC 27 August while
located about 900 n mi east of the Lesser Antilles.
Fran began to track toward the west-northwest in the wake of Hurricane Edouard.
Deep convection became more concentrated and Fran is estimated to have reached
hurricane status at 0000 UTC 29 August while centered about 400 n mi east of the
Leeward Islands. The center
of Fran was about 150 n mi to the northeast of the Leeward Islands near 1200 UTC 30 August.
The tropical cyclone
weakened to just below hurricane strength later on the 30th,
possibly due to the low-level inflow being disrupted again by Edouard.
About this time, changing steering currents caused Fran to turn toward the northwest and slow to
about 5 knots.
By 1200 UTC 31 August, as Edouard moved farther away, Fran had regained
hurricane strength. As Hurricane Edouard moved northward off the U.S.
mid-Atlantic coast, the subtropical ridge became better established to the north of Fran, causing Fran
to resume a west-northwestward motion with an increased forward speed of about 10
knots. Fran moved on a track roughly parallel to the Bahama Islands with the
eye remaining a little more than 100 n mi to the
northeast of the islands.
Fran strengthened to a category three hurricane by the
time it was northeast of the central Bahamas on 4 September. The powerful tropical cyclone
began to be influenced by a cyclonic circulation centered over Tennessee that was most pronounced
in mid to upper levels of the atmosphere. Fran was steered by the resulting flow around
the low over Tennessee and the western extension of the subtropical ridge over the
northwest Atlantic. The hurricane gradually turned toward the northwest to north-
northwest and increased in forward speed.
The minimum central pressure dropped to 946 mb and maximum sustained surface
winds reached 105 knots, Fran's peak intensity, near 0000 UTC 5 September
when the hurricane was centered about 250 n mi east of the Florida east coast.
Fran was moving northward near 15 knots when it made landfall on the North
Carolina coast. The center moved over the Cape Fear area around 0030 UTC 6
September, but the circulation and radius of maximum winds were large and hurricane
force winds likely extended over much of the North Carolina coastal areas of
Brunswick, New Hanover, Pender, Onslow and Carteret counties. At landfall, the
minimum central pressure is estimated at 954 mb and the maximum sustained surface
winds are estimated at 100 knots. The strongest winds likely occurred in
streaks within the deep convective areas north and northeast of the center.
Fran weakened to a tropical storm while centered over central North Carolina and
subsequently to a tropical depression while moving through Virginia. The tropical
cyclone gradually lost its warm core as it moved over the eastern Great Lakes and
became extratropical
near 0000 UTC 9 September while centered over southern Ontario. The remnants of
Fran were absorbed into a frontal system near 0600 UTC 10 September.
b. Meteorological Statistics
Figures 2 (57K GIF) and
3 (78K GIF) show
the curves of minimum central sea-level pressure and maximum one-minute "surface" wind speed,
respectively, as a function of time. The observations on which the curves are based are also
plotted and consist of aircraft reconnaissance data and Dvorak-technique estimates using
satellite imagery, as well as synoptic fixes after landfall. According to international
agreements within the world meteorological community, the surface wind is actually the wind
representative of 33 feet (10 meters) above the ground.
All operational aircraft reconnaissance flights into Fran were provided by the U.S. Air
Force Reserves. These
"Hurricane Hunters"
made 71
center fixes during 17 flights.
The minimum central pressure reported by aircraft was 946 mb at 2306 UTC 4
September. A circular eye with a diameter of 25 n mi was observed on aircraft radar
at this time. The 946 mb minimum pressure was measured by dropsonde and was the
lowest pressure reported during Fran's existence. The maximum winds of 114 knots
from a flight level of 700 mb (near 10,000 feet) were measured about 6 hours prior to
the 946 mb pressure report. Flight-level winds in excess of 100 knots were reported
several times during the two days prior to landfall. 113-knot winds were
reported from aircraft 52 n mi east of the hurricane center at 2314 UTC 5 September, and
107-knot winds were reported 41 n mi northeast of the center at the time
of landfall. However, the core of the hurricane weakened somewhat on radar presentations, and
a closed eyewall
was not reported by aircraft during the two hours prior to the center moving onshore.
Objective intensity estimates from digital infrared satellite imagery peaked near the
time that the minimum central pressure was reported by reconnaissance aircraft.
The WSR-88D (Weather Surveillance Radar - 1988 Doppler) at
Wilmington, North Carolina,
measured winds in excess of 120 knots aloft as the inner convective
bands approached the Cape Fear area at 2130 UTC 5 September.
A ship with call sign LAVX4 reported 85 knot winds
and a pressure of 984 mb at 1800 UTC 5 September while located about 60 n mi northeast of the hurricane
center. Several other ship reports were helpful in defining the extent of tropical storm force
winds, as were reports from a network of drifting buoys deployed offshore of the
Carolinas in advance of Fran. Table 2 lists ship reports of at
least tropical storm force winds in the vicinity of Fran.
Several wind gusts to hurricane force were measured from coastal areas in North
Carolina. As usual for landfalling hurricanes, however, reports of sustained hurricane
force winds are difficult to find. Table 3 lists selected U.S.
surface observations. The NOAA C-MAN station
at Frying Pan Shoals (about 50 n mi south-southeast of Wilmington, North Carolina) reported
sustained winds of 79 knots and gusts to 108 knots
from a tower about 80 feet above sea level.
Numerous pressure and wind reports from North Carolina were relayed to the NHC
through amateur radio volunteers. The lowest measured pressure was 954 mb from
Southport. The highest measured wind gust was 119 knots at an elevation
of 30 feet (mounted on a house approximately 4 feet above the chimney) from a Davis wind
instrument located on Hewletts Creek in Wilmington. A gust to 109 knots was
measured in Wrightsville Beach. Although these measurements are very much desired
to supplement the more official observations, they will not be listed in
Table 3 until their accuracy is verified.
Several tornadoes were indicated by Doppler radar in North Carolina and Virginia.
Confirmation, however, has been difficult due to the extensive nature of straight line
wind damage across the region.
At the time of this report, a post-storm high water mark survey was being conducted
by the U.S. Army Corps of Engineers and the U.S. Geological Survey. Many high
water marks remain to be surveyed and "tied into" bench marks. The locations of the
maximum values cannot be finalized until the survey is complete. However, initial
survey results show an extensive storm surge along the North Carolina coast primarily
southwest of Cape Lookout. Still water mark elevations on the inside of buildings,
indicative of the storm surge, range from 8 to 12 feet. Outside water marks on
buildings or debris lines are higher due to the effect of breaking waves.
Rainfall totals exceeding six inches were common near the path of Fran. WSR-88D
radar precipitation estimates were as high as 12 inches over portions of Brunswick and
Pender counties in North Carolina. Extensive flooding spread well inland from the
Carolinas into Virginia, West Virginia and Pennsylvania. Some of this flooding was
considered the most severe in years. Near Washington, D.C., for example, the Old
Town district of historic Alexandria was partially evacuated as the Potomac River rose,
flooding streets with more than three feet of water. The next update of this report will
include an analysis of rainfall along the path of Fran to be provided by the
NWS Eastern Region Headquarters.
c. Casualty and Damage Statistics
According to Associated Press reports, Hurricane Fran was responsible for 34
deaths. Most of the deaths were caused by flash flooding in the Carolinas, Virginia,
West Virginia and Pennsylvania. Twenty-one died in North Carolina alone. However,
the total death count will likely be revised downward in the next update of this report
based on data from NWS personnel to be published in Storm Data, since the
NWS attempts to list deaths directly
attributable to the weather. For example, most vehicle accidents and heart attacks
from over-exertion after a hurricane are not considered direct deaths.
Storm surge on the North Carolina coast destroyed or seriously damaged numerous
beachfront houses. Widespread wind damage to trees and roofs, as well as downed
power lines, occurred as Fran moved inland over North Carolina and Virginia.
Extensive flooding was responsible for additional damage in the Carolinas, Virginia,
West Virginia, Maryland, Ohio and Pennsylvania.
Nearly a half-million tourists and residents were ordered to evacuate the coast in
North and South Carolina. Press reports from Reuters News Service stated that 4.5
million people in the Carolinas and Virginia were left without power.
The Property Claim Services Division of the American Insurance Services Group
reports that Fran caused an estimated $1.6 billion dollars in insured property damage
to the United States. This estimate includes $1.275 billion in North Carolina, $20
million in South Carolina, $175 million in Virginia, $50 million in Maryland, $20
million in West Virginia, $40 million in Pennsylvania and $20 million in Ohio. A
conservative ratio between total damage and insured property damage, compared to
past landfalling hurricanes, is two to one. Therefore, the total U.S. damage estimate
is $3.2 billion.
d. Forecast and Warning Critique
During Fran's life as a tropical storm or hurricane, the average official track
forecast errors ranged from 66 n mi at 24 hours (37 cases) to 137 n mi at 48 hours (33
cases) to 185 n mi at 72 hours (29 cases). These errors are at least 25 percent less
than the previous ten-year averages of the official track errors.
The BAMD (deep-layer Beta and Advection Model) and the GFDI (interpolated version
of the Geophysical Fluid Dynamics Laboratory model) provided the best guidance in
terms of the lowest track forecast errors. However, the GFDI model showed a
distinct bias to the left of the actual track (Figure 4) (77K GIF).
The guidance from this model, which is generally acknowledged to be the most accurate one
operationally available to the NHC, resulted in some left bias in the official forecasts
near landfall.
Most NHC intensity forecast errors were 15 knots or less. All but one intensity
forecast made after 2100 UTC 02 September correctly indicated a landfalling category
three hurricane.
Table 4 lists the various watches and warnings that were issued.
Hurricane warnings were posted
for the hardest hit portions of the North Carolina coast about 27 hours prior to landfall.
Acknowledgments
Some of the information in this report was provided by
NWS offices in the
Eastern Region
and is greatly appreciated. Stephen Baig prepared
Fig. 1, and Mike Hopkins
assisted with Table 3.
Table 4. Watch and warning summary, Hurricane Fran, 23 August - 8 September,
1996.
Date/time (UTC) | Action | Location |
29/0300 | hurricane watch |
Northeastern Leeward Islands from Antigua through St. Maartin |
29/2100 | hurricane watch discontinued |
Northeastern Leeward Islands from Antigua through St. Maartin |
hurricane watch | Central Bahamas |
tropical storm warning | Central Bahamas |
03/0900 | hurricane watch |
Northwestern Bahamas |
03/1800 | hurricane warning |
Northwestern Bahamas |
04/0300 | hurricane watch |
north of Sebastien Inlet, FL to Little River Inlet, SC |
04/0900 | watches and warnings discontinued |
Central Bahamas |
04/1500 | hurricane watch extended northward |
Little River Inlet, SC to Oregon Inlet, NC including Pamlico Sound |
04/1800 | hurricane warning downgraded to
tropical storm warning |
Northwestern Bahama Islands of Andros and New Providence |
04/2100 | hurricane warning |
north of Brunswick, GA to Cape Lookout, NC |
hurricane watch |
north of Cape Lookout, NC to Currituck Beach Light, NC including Pamlico
and Albemarle Sounds |
tropical storm warning |
Flagler Beach, FL to Brunswick, GA |
hurricane watch discontinued |
south of Cape Lookout, NC |
05/0300 |
hurricane warning extended northward |
north of Cape Lookout, NC to NC/VA border including the Pamlico and Albemarle Sounds |
hurricane watch |
north of NC/VA border to Chincoteague, VA including the Greater Hampton Roads area |
hurricane warning downgraded to
tropical storm warning |
northwestern Bahama Islands of Abaco and Grand Bahama |
hurricane warning discontinued |
northwestern Bahama Islands |
tropical storm warning discontinued |
Andros and New Providence Islands |
05/0900 |
tropical storm warning discontinued |
Flagler Beach, FL to Brunswick, GA |
tropical storm warning discontinued |
northwestern Bahama Islands of Abaco and Grand Bahama |
05/1500 | tropical storm warning |
north of the NC/VA border to Chincoteague, VA including the Greater Hampton Roads area |
tropical storm warning | lower Chesapeake Bay |
hurricane warning downgraded to
tropical storm warning |
north of Brunswick, GA to just south of Edisto Beach, SC |
06/0100 |
hurricane and tropical storm warnings discontinued |
Cape Romain, SC southward |
06/0300 |
hurricane warnings discontinued |
south of Cape Fear, NC |
hurricane watch discontinued |
north of the NC/SC border to Chincoteague, VA including the Greater Hampton Raods area |
06/0900 | hurricane warning discontinued |
remainder of NC coast |
06/1800 | tropical storm warning discontinued |
remainder of U.S. east coast |