Dennis was a larger-than-average western Atlantic hurricane that was erratic
in both track and intensity. Although it never made landfall as a hurricane,
it affected the North Carolina coast with hurricane force winds, heavy
rains, prolonged high surf, and beach erosion. Dennis also produced tropical
storm force winds over portions of the Bahamas.
a. Synoptic History
The origin of Dennis can be traced to a tropical wave that moved off the
coast of Africa on 17 August. The system moved westward with little
significant weather until 21 August, when associated shower activity
increased a few hundred miles northeast of the Leeward Islands. A low- level
circulation developed over the next two days as convective organization
increased. An investigative flight by the Air Force Reserve Hurricane
Hunters failed to find a surface circulation on the 23rd. However,
the aircraft data indicated a circulation was present at 850 mb. Later
surface observations showed a closed circulation, and it is estimated that
Tropical Depression Five formed at 0000 UTC 24 August about 190 n mi east of
Turks Island (Table 1 and Figure 1).
Reconnaissance data and ship reports
indicated further intensification, and the depression became Tropical Storm
Dennis at 1200 UTC the same day.
The initial structure was unusual. Dennis was at the east-southeast end of
an elongated trough that extended to southern Florida. This and upper-level
westerly shear caused an asymmetric pattern of convection and tropical storm
force winds, with both confined to the eastern semicircle on 24-25 August.
Despite the shear, the cyclone intensified unsteadily and reached hurricane
strength early on the 26th.
The unusual structure may have also affected the cyclone's motion. Dennis
initially moved at 9 to 12 kt, but slowed to an erratic 3 kt on 25 August as
steering currents weakened due to a mid-latitude trough passing to the
north. At one time that day, the center appeared to re-form eastward along
the trough axis. Once Dennis reached hurricane strength, it began a more
steady northwestward motion near or over the eastern Bahamas.
This motion continued into the 28th.
Westerly shear persisted, preventing significant strengthening until late on
27 August. After the shear decreased, Dennis reached a peak intensity of 90 kt
on the 28th and maintained that intensity until early on the
30th. Even at peak intensity, Dennis never consolidated into a
classic tightly-wound hurricane. The eye was 30 to 40 miles wide, and on
several center fixes the Hurricane Hunters did not report an eye. The radius
of maximum winds was as large as 70 to 85 nm on the 29th and
30th.
A second mid-latitude trough caused Dennis to turn gradually northward on
28-29 August, which was followed by acceleration to the east-northeast on
30th and 31th. This turn kept the center about 60 miles
south of the North Carolina coast. The east-northeast motion continued until
the trough passed Dennis on the 31st. At that time, steering
current collapsed and the cyclone slowed to an erratic drift about 110 n mi
east of Cape Hatteras, NC. The erratic motion would last into 2 September.
During this time, Dennis became involved with the cold front associated with
the mid-latitude trough. A combination of vertical shear and cool dry air
entraining into the circulation decreased the convection and weakened the
cyclone. Dennis weakened to a tropical storm on 1 September, and on the
1st and 2nd may have been as much a subtropical or
extratropical cyclone as a tropical cyclone. Despite the lack of convection,
surface observations indicate maximum sustained winds were near 45 kt during
2 September. Some of these winds were due to the combination of Dennis and a
strong surface ridge north of the front, which caused 34 kt or greater winds
as far north as the New Jersey coast.
A large westerly ridge over the eastern United States forced Dennis
southward late on 2 September. This motion toward warmer water probably
aided a deep convective burst on the next day. Later that day, Dennis turned
northwest toward the North Carolina coast as the ridge moved east into the
Atlantic. This motion continued on the 4th along with
re-intensification. Dennis was just below hurricane strength when it made
landfall over the Cape Lookout National Seashore just east of Harkers
Island, NC at 2100 UTC that day. Dennis continued inland and weakened to a
depression on the 5th over central North Carolina. Even in
dissipation, Dennis continued to move erratically. Figure 1 shows that the
cyclone followed a zig-zag course northward for the rest of its life. Dennis
became extratropical on the 7th and was absorbed into a larger
low on the 9th.
b. Meteorological Statistics
Table 1 shows the best track positions and intensities
for Dennis, with the track plotted in Figure 1.
Figure 2 and Figure 3 depict the
curves of minimum central sea-level pressure and maximum sustained
one-minute average "surface" (10 m above ground level) winds, respectively,
as a function of time. These figures also contain the data on which the
curves are based: aircraft reconnaissance and dropsonde data from the Air
Force Reserve Hurricane Hunter and NOAA, satellite-based Dvorak technique
intensity estimates from the Tropical Analysis and Forecast Branch (TAFB),
the Synoptic Analysis Branch (SAB) of the National Environmental Satellite
Data and Information Service (NESDIS), and the Air Force Weather Agency, and
estimates from synoptic data.
1. Wind and Pressure Data
The Hurricane Hunters flew 24 missions into Dennis and made 81 center fixes,
and NOAA research aircraft provided three additional fixes during various
research missions. The maximum reported wind was 110 kt (at 700 mb) at 2002
UTC 28 August. While taking 90% of this wind would suggest a maximum
sustained surface wind of 99 kt, dropsonde observations at that time do not
support that high of a surface wind. The minimum observed central pressure
observed from dropsondes was 962 mb at 0350 and 0543 UTC on 30 August. A 959
mb pressure was estimated from 700 mb data at 1017 UTC on the 30th,
(Figure 2), but is believed to be too low. The Hurricane
Hunters also measured 71 kt winds (at 850 mb) and a 984 mb pressure just
before Dennis made landfall on 4 September. These data indicate Dennis was a
60 kt tropical storm at landfall.
Dennis's path brought it near the eastern Bahamas on 27-28 August. The only
official report of tropical storm force winds in the Bahamas was from the
Coastal Marine Automated Network (C-MAN) station at Settlement Point, Grand
Bahama, which reported 34 kt sustained winds with gusts to 46 kt at 0030 UTC
29 August. (This and other available surface observations are summarized in
Table 2.) However, reports relayed to the NHC through
amateur radio operators indicated sustained winds of up to 60 to 65 mph with
gusts of 70 to 75 mph in the Abaco island group. Reported pressures were as
low as 976 mb as the western part of the eye passed over the Abacos around
0700 to 1000 UTC on the 28th. While these observations are
significant, their reliability is uncertain. Therefore, they are not included
in Table 2.
Dennis tracked parallel to the Florida and Georgia coasts, with tropical
storm force winds remaining mostly offshore. The only reported tropical
storm force wind was a 41 kt gust at the St. Augustine, FL C-MAN station.
The core of Dennis passed just east of NOAA buoy 41010 on 29 August, which
reported 57 kt sustained winds with gusts to 72 kt at 0500 UTC and a minimum
pressure of 980.2 mb at 0750 UTC.
Dennis's first pass near the coast of the Carolinas on 30 August caused
sustained tropical storm force winds with gusts to hurricane force in
coastal North Carolina and gusts to tropical storm force in coastal South
Carolina from Charleston northward. The maximum reported sustained winds
were 53 kt with gusts to 77 kt at Oregon Inlet at 2030 UTC. It is not clear
whether sustained hurricane force winds affected the coast. There are no
observations of such winds, and analyses from the Hurricane Research
Division suggests they stayed offshore. However, gusts to 96 kt at
Wrightsville Beach and 85 kt at Hatteras Village
(Table 2) suggest that
sustained hurricane force winds may have occurred along the coasts of New
Hanover and Dare counties. Sustained hurricane force winds of 81 kt with
gusts to 97 kt were measured at the Frying Pan Shoals C-MAN station (145 ft
elevation) at 0945 UTC 30 August, with a minimum pressure of 977.2 mb at
0900 UTC.
The landfall of Dennis on 4 September produced tropical storm force winds
over portions of eastern North Carolina and coastal southeastern Virginia.
Langley Air Force Base VA, reported 45 kt sustained winds with gusts to 66
kt at 2330 UTC, while Cherry Point Marine Corp Air Station NC, reported 41
kt sustained winds with gusts to 53 kt at 2005 UTC.
The large circulation of Dennis also affected shipping over a portion of the
western Atlantic. Table 2a shows the available ship
observations of tropical storm force or greater winds. The
maximum ship-observed winds were 65 kt from the Zim U.S.A. at
0900 UTC 30 August, while the lowest observed pressure was 987.3 mb from the
Hoegh Dene at 1800 UTC 4 September. Observations from the
Sealand Crusader on 24 August were important in determining that the
pre-Dennis wave had developed into a depression.
2. Storm Surge Data
Few detailed observations of storm surge are available from areas affected
by Dennis (Table 2). Storm tides of 3 to 5 ft above
normal were reported along much of the North Carolina coast on both 30
August and 4 September. Areas along the Neuse River reported tides of 8 to
10 ft above normal tide level on 30 August, while areas along the Pamlico
River reported similar values on 4 September. Portions of the South Carolina
and southeastern Virginia coast experienced 2 to 4 ft above normal tides
during Dennis, while amateur radio reports from the Bahamas indicate tides 1
to 3 ft above normal as the eye passed over the Abacos.
Since Dennis meandered off the North Carolina coast for several days, the
above normal tides were unusually prolonged. This led to extensive beach
erosion along portions of the North Carolina and southeastern Virginia
coasts.
3. Rainfall data
Dennis affected the mid-Atlantic states twice within a week, and other
weather systems affected the region during the same period. This makes
determination of storm total rainfall in that area difficult.
Table 2 shows
the storm total rainfalls for Dennis, including the best estimates in North
Carolina and Virginia. The maximum reported total was 19.13 inches at
Ocracoke NC, with 6 to 10 inches reported elsewhere over portions of eastern
North Carolina. Rainfalls of 3 to 6 inches occurred elsewhere over eastern
North Carolina, extreme eastern South Carolina, and over portions of
southeastern Virginia. Rainfalls were generally 1 to 3 inches elsewhere over
eastern South Carolina and less than an inch in Florida and Georgia.
Dennis and the other weather systems contributed to a wet period over
portions of the mid-Atlantic states. Table 2b shows
11-day rainfall totals of 6 inches or more ending at 1200 UTC 8 September.
The heaviest rainfalls were observed over eastern North Carolina and central
Virginia. While this rainfall broke a prolonged dry spell in the area, it
also set the stage for the severe flooding caused by Hurricane Floyd two
weeks later.
Official rainfall data from the Bahamas indicates a maximum total of 4.00
inches at Cat Island. Heavier amounts likely occurred on Eleuthera and in
the Abaco group near the eye of Dennis.
4. Tornadoes
One tornado was reported with Dennis on 4 September. This F2 tornado in
Hampton VA caused an estimated $7 million damage and 15 injuries, 6 of them
serious.
c. Casualty and Damage Statistics
Four deaths reported in Florida were related to high surf spawned by the
hurricane. No deaths are known due to winds, rains, storm tides or tornadoes
associated with Dennis.
In the United States, the Property Claims Services Division of the Insurance
Services Office reports insured losses due to Dennis totaled $60 million in
North Carolina and Virginia. To determine the total property damage, a two
to one ratio is applied to the insured property damage based on comparisons
done in historical hurricanes. Press reports indicate that agricultural
losses in North Carolina and Virginia were $37 million. Combining these
reports gives a total estimated damage from Dennis of $157 million.
There are no damage reports available from the Bahamas as of this time.
d. Forecast and warning critique
Table 3 shows the track forecast errors during Dennis
for the official NHC track forecast and a selection of objective guidance
models. The official forecasts were generally quite good with errors of
about 60% to 70% of the long term average. The official forecasts also were
better than the objective guidance with two exceptions: The United Kingdom
Meteorological Office global model (UKM) was slightly better than the
official forecast at all time periods, and the barotropic model LBAR was
slightly better at 12 and 24 hours. It should the noted that the UKMI, which
is the interpolated UKM track forecast available to hurricane forecasters in
real time, was slightly worse than the official forecast at all time
periods. There were two periods with worse than average official track
forecasts. The first was on 24 August, as the poorly-organized Dennis
consistently moved slower than forecast. The second on was 28 August, when
the motion parallel to the coast on 30-31 August was poorly forecast.
While intensity forecast errors were also better than the long term average,
there was a significant positive bias which is counter to the 10-year
average. This occurred due to forecasts on 28-30 August which predicted
Dennis to remain a hurricane when it actually weakened to a tropical storm.
Three consecutive forecasts during this time overforecasted the 72 hour
intensity by 50 kt.
Table 4 shows the watches and warnings that were
issued for Dennis. Due to the somewhat erratic motion near the Bahamas,
hurricane warnings were issued for Eleuthera and the Abacos 40 hours before
the eye passed over the Abacos. While tropical-storm force winds did not
occur over land south of Charleston, SC, they were present over the Florida,
Georgia, and South Carolina coastal waters. Hurricane warnings for the North
Carolina coast on 29 August had less than the normally-desired 24 hour lead
time. However, these were issued in anticipation that Dennis' large size and
track just offshore would cause hurricane conditions along the coast and not
in anticipation of a landfall. Hurricane warnings were also issued for the
North Carolina coast on 4 September in anticipation of Dennis regaining
hurricane strength before landfall. These proved to be unnecessary.
Acknowledgments:
Much of the data in this report was provided by the local National Weather
Service forecast offices in Miami, Melbourne, Jacksonville, Charleston,
Wilmington, Morehead City, and Wakefield. Buoy and C-MAN station data was
provided by the National Data Buoy Center. James Franklin created the wind
and pressure plots.
Figure 1.
Best track for Hurricane Dennis, 24 August - 7 September 1999.
Figure 2.
Best track minimum central pressure curve for Hurricane Dennis,
24 August - 7 September 1999.
Figure 3.
Best track maximum sustained 1-minute 10 meter wind speed curve for
Hurricane Dennis, 24 August - 7 September, 1999.
Table 1. Best track, Hurricane Dennis, 24 August - 7 September 1999
Date/Time (UTC) | Position |
Pressure (mb) |
Wind Speed (kt) | Stage |
Lat. (°N) | Lon. (°W) |
24/0000 | 21.5 | 67.7 | 1009 | 30 | tropical depression |
24/0600 | 22.0 | 68.9 | 1009 | 30 | " |
24/1200 | 22.4 | 70.0 | 1009 | 35 | tropical storm |
24/1800 | 22.7 | 70.9 | 1009 | 40 | " |
25/0000 | 22.8 | 71.5 | 1008 | 40 | " |
25/0600 | 23.0 | 71.9 | 1007 | 40 | " |
25/1200 | 23.2 | 72.1 | 1004 | 45 | " |
25/1800 | 23.4 | 72.3 | 1000 | 55 | " |
26/0000 | 23.6 | 72.5 | 998 | 60 | " |
26/0600 | 23.8 | 73.1 | 995 | 65 | hurricane |
26/1200 | 24.1 | 73.6 | 995 | 65 | " |
26/1800 | 24.4 | 74.0 | 990 | 70 | " |
27/0000 | 24.8 | 74.4 | 993 | 65 | " |
27/0600 | 25.2 | 75.0 | 988 | 65 | " |
27/1200 | 25.6 | 75.5 | 988 | 65 | " |
27/1800 | 25.9 | 75.9 | 987 | 65 | " |
28/0000 | 26.1 | 76.2 | 982 | 70 | " |
28/0600 | 26.5 | 76.7 | 976 | 75 | " |
28/1200 | 27.1 | 77.0 | 973 | 85 | " |
28/1800 | 27.7 | 77.3 | 969 | 90 | " |
29/0000 | 28.3 | 77.7 | 969 | 90 | " |
29/0600 | 29.0 | 77.9 | 970 | 90 | " |
29/1200 | 29.9 | 78.4 | 971 | 90 | " |
29/1800 | 30.8 | 78.4 | 967 | 90 | " |
30/0000 | 31.9 | 78.1 | 964 | 90 | " |
30/0600 | 32.8 | 77.6 | 962 | 90 | " |
30/1200 | 33.6 | 76.5 | 965 | 85 | " |
30/1800 | 34.3 | 74.8 | 966 | 85 | " |
31/0000 | 34.9 | 73.6 | 971 | 80 | " |
31/0600 | 35.1 | 72.9 | 977 | 80 | " |
31/1200 | 35.2 | 72.8 | 983 | 75 | " |
31/1800 | 35.1 | 73.3 | 984 | 70 | " |
01/0000 | 35.2 | 73.6 | 986 | 60 | tropical storm |
01/0600 | 35.0 | 73.4 | 987 | 55 | " |
01/1200 | 35.4 | 73.5 | 989 | 50 | " |
01/1800 | 35.5 | 73.8 | 988 | 50 | " |
02/0000 | 35.4 | 73.7 | 988 | 50 | " |
02/0600 | 35.2 | 73.6 | 989 | 45 | " |
02/1200 | 35.1 | 73.7 | 989 | 45 | " |
02/1800 | 34.8 | 73.9 | 990 | 45 | " |
03/0000 | 34.2 | 74.0 | 989 | 45 | " |
03/0600 | 33.6 | 74.1 | 989 | 45 | " |
03/1200 | 33.2 | 73.9 | 988 | 45 | " |
03/1800 | 33.0 | 73.8 | 987 | 50 | " |
04/0000 | 33.1 | 74.0 | 987 | 50 | " |
04/0600 | 33.3 | 74.5 | 986 | 55 | " |
04/1200 | 33.9 | 75.3 | 986 | 55 | " |
04/1800 | 34.5 | 76.0 | 986 | 60 | " |
05/0000 | 35.0 | 76.8 | 985 | 50 | " |
05/0600 | 35.5 | 77.7 | 989 | 35 | " |
05/1200 | 36.1 | 78.8 | 994 | 30 | tropical depression |
05/1800 | 36.2 | 79.4 | 998 | 25 | " |
06/0000 | 36.2 | 79.9 | 1000 | 25 | " |
06/0600 | 36.4 | 80.1 | 1004 | 20 | " |
06/1200 | 37.0 | 79.9 | 1005 | 20 | " |
06/1800 | 37.7 | 79.5 | 1008 | 20 | " |
07/0000 | 38.5 | 78.5 | 1009 | 20 | " |
07/0600 | 40.8 | 77.0 | 1008 | 20 | " |
07/1200 | 42.7 | 77.7 | 1007 | 20 | " |
07/1800 | 43.5 | 77.7 | 1006 | 20 | extratropical |
08/0000 | 43.5 | 76.5 | 1006 | 20 | " |
08/0600 | 44.0 | 75.8 | 1006 | 20 | " |
08/1200 | 44.9 | 74.8 | 1006 | 20 | " |
08/1800 | 45.5 | 75.6 | 1005 | 20 | " |
09/0000 | | | | | lost identity |
|
30 /0600 | 32.8 | 77.6 | 962 | 90 | minimum pressure |
Landfalls: |
28/0700 | 26.6 | 76.8 | 976 | 75 | Abaco Islands, Bahamas |
04/2100 | 34.8 | 76.5 | 984 | 60 | Cape Lookout National Seashore, NC |
Table 2. Hurricane Dennis selected surface observations, 24 August - 7 September 1999.
(Incomplete pending further data from NDBC)
|
Minimum sea-level pressure |
Maximum surface wind speed (kt) |
|
Location |
Pressure (mb) |
Date/time (UTC) |
Sustained wind (kts) a |
Peak gust (kts) |
Date/timeb (UTC) |
Storm surgec (ft) |
Storm tided (ft) |
Rain (storm total) (in) |
Bahamas |
Cat Island | | | | | | | | 4.00 |
North Carolina |
Alligator Bridge# | | | 48 | 56 | 30/1100 | | | |
Atlantic (Texas Tech tower, 30 ft) | 992.6 | 30/1351 | 48 | 75 | 30/1532 | | | |
Beaufort | 984.8 | 04/2049 | 33 | 45 | 04/1823 | | | |
Beaufort (Texas Tech tower, 33 ft) | 992.8 | 30/1302 | 52 | 75 | 30/1103 | | | |
Blockade Runner | | | | 72 | | | | |
Brunswick Cnty Airport | | | | 61 | 30/0810 | | | |
Brunswick Power Plant | | | 50g | | 30/0456 | | | |
Calabash | | | | 35 | | | | 1.57 |
Carolina Beach | | | | 66 | 30/0710 | | | |
Castle Hayne (Oxychem) | | | | 54 | 30/1100 | | | |
Castle Hayne (SW) | | | 35 | 67 | 30/0900 | | | |
Cherry Point MCAS | 986.5 | 04/2355 | 41 | 53 | 04/2005 | | | 9.24 |
Delco | | | 28 | 57 | 30/1200 | | | |
East Waccamaw | | | | 34 | 30/1100 | | | 0.98 |
Elizabeth City | 1003.8 | 04/2313 | 34 | 45 | 30/1654 | | | 7.01 |
Elizabethtown | | | | 37 | | | | |
Flemington | | | 39 | 68 | 30/0900 | | | |
Greenville | | | | 43 | 05/0140 | | | |
Harkers Island Bridge | | | | 76 | 30/1230 | | | |
Hatteras Inlet | | | 50$ | 64 | 30/1930 | | | |
Hatteras Village | | | | 85 | 30/1515 | | | |
Jacksonville | 994.2 | 05/0235 | | 41 | 30/0835 | | | |
Kingston | | | | 37 | 04/2250 | | | |
Kure Beach | | | | 58 | 30/0740 | | | |
Kure Beach (Federal Point) | | | | 71 | 30/0530 | | | |
Manteo | | | | 52 | 30/1635 | | | |
New Bern | 986.8 | 05/0000 | 35 | 46 | 30/1056 | | | 3.35 |
New River | 993.9 | 04/2126 | 33 | 50 | 30/0956 | | | 5.75 |
Newport | 985.1 | 04/2115 | | 54 | 30/1204 | | | 9.89 |
North Topsail Beach | | | 44$ | 65 | 30/1240 | | | |
Oak Island | | | 46 | 62 | 30/0800 | | | |
Ocean Isle | | | | 49 | 30/0559 | | | |
Ocean Isle (Tubbs Inlet) | | | | 46 | 30/0753 | | | |
Ocracoke Island# | 995.1 | 31/0740 | 35$ | 58 | 31/0220 | | | 19.13 |
Oregon Inlet | | | 53$ | 77 | 30/2030 | | | |
Oriental | | | | | | | 6-8 | |
St. James | | | | | | | | 6.00 |
Shallotte | | | | 60 | 30/0700 | | | |
Shallotte Inlet | | | | 60 | 30/0730 | | | |
Southport (Elementary) | | | | 49 | | | | 9.01 |
Southport (Marina) | | | | | | | | 13.50 |
Southport (Pilot Boat Dispatch) | | | | 60 | 30/0743 | | | |
Washington | | | | 41 | 30/1520 | | | |
Whiteville | | | | 37 | | | | 1.97 |
Wilmington Airport | 996.1 | 0953 | 42 | 53 | 30/0607 | | | 4.73 |
Wilmington (Battleship North Carolina) | | | | 66 | 30/0530 | | | 6.70 |
Wilmington (College RD/Oleander DR) | | | | 46 | | | | 8.75 |
Wilmington (Corning) | | | | 60 | 30/1200 | | | |
Wilmington (Eastwood RD/Military Cutoff) | | | | 44 | 30/0650 | | | 6.60 |
Wilmington (Masonboro Loop) | | | | 37 | | | | |
Wilmington (New Hanover EOC) | | | 51 | 76 | 30/0800 | | | |
Wilmington (WECT-TV) | | | | 46 | | | | 5.07 |
Wrightsville Beach | | | | 96 | 30/0444 | | | |
Wrightsville Beach Fire Dept. | | | | 73 | 30/0630 | | | |
South Carolina |
Charleston Harbor | | | | | | | 2.0 | |
Charleston WFO | | | 29 | 40 | 29/2050 | | | 1.22 |
Murrells Inlet | | | | | | | | 2.88 |
Myrtle Beach (Pavilion) | | | | 45 | 30/0600 | | | |
N. Myrtle Beach | | | 29 | 42 | 30/0732 | | | 1.65 |
Virginia |
John Kerr Dam | | | | | | | | 3.38 |
Norfolk Airport | 1006.1 | 05/0551 | 37 | 46 | 30/1651 | | | 3.30 |
Langely AFB | 1007.1 | | 45 | 66 | 04/2332 | | | |
Newport News | 1006.5 | | 28 | 39 | 04/2332 | | | 3.32 |
Norfolk NAS | 1006.5 | | | | | | | 2.85 |
Oceana NAS | 1006.5 | | | | | | | 2.90 |
Portsmouth | | | | | | | | 5.75 |
Richmond | 1006.5 | 05/0754 | | | | | | 2.18 |
Roanoke Rapids | | | 27 | 35 | 30/1214 | | | |
Sewells Point | | | | | | | 3.0 | |
Wakefield | | | | | | | | 4.59 |
Wallops Island | | | 33 | 40 | 30/1717 | | | |
NOAA Buoys and C-MAN Stations |
Buoy 41001 | 976.0 | 31/0400 | 48$ | 63 | 30/2300 | | | |
Buoy 41002 | 997.6 | 30/1100 | 43$ | 59 | | | | |
Buoy 41004 | 990.5 | 30/0300 | 54$ | 72 | 30/0330 | | | |
Buoy 41008 | 1003.9 | 29/2000 | 31 | 43 | 29/1700 | | | |
Buoy 41009# | 1001.3 | 29/0900 | 29 | 37 | 29/0700 | | | |
Buoy 41010 | 980.2 | 29/0750 | 57 | 72 | 29/0500 | | | |
Buoy 44014 | 1002.3 | 30/2000 | 43 | 53 | 30/2100 | | | |
Drifting Buoy 41650# | 1009.8 | 27/0000 | 45 | | 27/1200 | | | |
Drifting Buoy 41651# | 1010.8 | 25/2100 | 42 | | 25/2100 | | | |
Cape Lookout NC (CKLN7) | 986.5 | 04/2000 | 60 | 79 | 30/1400 | | | |
Chesapeake Bay VA (CHLV2) | 1006.2 | 05/0600 | 49$ | 56 | 30/2100 | | | |
Duck NC (DUCN7) | 1005.6 | 04/2300 | 56 | 65 | 30/2000 | | | |
Folly Beach SC (FBIS1) | 1001.6 | 30/0100 | 24 | 35 | 30/0000 | | | |
Frying Pan Shoals NC (FPSN7) | 977.2 | 30/0900 | 81$ | 97 | 30/0945 | | | |
Settlement Point, BI (SPGF1) | 1002.6 | 28/2200 | 34$ | 46 | 29/0030 | | | |
St. Augustine FL (SAUF1) | 1004.9 | 29/1100 | 27 | 41 | 29/1355 | | | |
aStandard NWS ASOS and C-MAN averaging period is 2 minutes; buoys are 8 minutes.
bDate/time is for sustained wind when both sustained and gust are listed.
cStorm surge is water height above normal astronomical tide level.
dStorm tide is water height above NGVD.
eEstimated.
$10 min average.
g100 ft tower, 15 min average.
#Incomplete record.
Table 2a. Ship observations of tropical storm or greater winds associated with Hurricane Dennis, 24 August -
7 September 1999.
Ship |
Date/Time (UTC) |
Lat. (°N) |
Lon. (°W) |
Wind dir/speed (deg/kt) |
Pressure (mb) |
Sealand Crusader | 24/0600 | 21.0 | 67.0 | 130/35 | 1011.5 |
Iver Express | 24/1800 | 23.2 | 74.6 | 010/39 | 1012.0 |
Jo Sypress | 26/1500 | 25.9 | 73.0 | 120/39 | 1012.5 |
Nomzi | 27/0000 | 25.9 | 74.3 | 090/44 | 1010.0 |
Nomzi | 27/0300 | 25.9 | 74.0 | 090/45 | 1010.0 |
Nomzi | 27/0600 | 26.0 | 73.7 | 070/40 | 1011.0 |
Star Hidra | 28/2100 | 30.1 | 77.5 | 050/40 | 1005.0 |
Morelos | 28/2100 | 26.2 | 74.4 | 170/34 | 1007.0 |
Torm Freya | 29/0000 | 30.2 | 75.5 | 100/35 | 1005.0 |
Nedlloyd Holland | 29/0000 | 27.8 | 79.2 | 340/42 | 1002.0 |
Star Hidra | 29/0000 | 30.0 | 77.0 | 050/41 | 1004.0 |
Nedlloyd Holland | 29/0300 | 28.7 | 79.9 | 340/39 | 1002.2 |
Star Hidra | 29/0300 | 29.5 | 76.4 | 090/55 | 1001.0 |
Torm Freya | 29/0600 | 29.5 | 74.8 | 150/48 | 1005.0 |
Star Hidra | 29/0600 | 29.8 | 76.5 | 120/56 | 999.3 |
Star Hidra | 29/0900 | 29.7 | 76.4 | 150/56 | 999.5 |
Star Hidra | 29/1200 | 29.6 | 76.2 | 160/55 | 1000.5 |
Star Hidra | 29/1500 | 29.3 | 76.1 | 180/46 | 1003.0 |
Torm Freya | 29/1800 | 28.3 | 74.9 | 190/46 | 1007.0 |
Zim U.S.A. | 29/2100 | 32.0 | 75.0 | 140/38 | 1006.0 |
Star Hidra | 29/2100 | 28.8 | 77.1 | 210/37 | 1005.5 |
Zim U.S.A. | 30/0000 | 32.0 | 75.1 | 160/40 | 1004.0 |
Zim U.S.A. | 30/0300 | 32.0 | 75.3 | 160/50 | 1002.0 |
Zim U.S.A. | 30/0600 | 31.8 | 75.5 | 180/65 | 999.0 |
OOCL Fair | 30/0600 | 33.4 | 74.3 | 150/40 | 1005.0 |
Zim U.S.A. | 30/0900 | 32.3 | 75.0 | 180/65 | 1000.0 |
OOCL Fair | 30/0900 | 32.7 | 74.3 | 180/50 | 1002.0 |
Zim U.S.A. | 30/1200 | 31.4 | 75.7 | 250/50 | 1002.5 |
SHIP | 30/1200 | 36.9 | 75.0 | 040/40 | 1014.5 |
Zim U.S.A. | 30/1500 | 31.5 | 76.3 | 270/50 | 1006.0 |
OOCL Fair | 30/1500 | 32.1 | 74.6 | 210/50 | 1002.0 |
Inspiration | 30/1800 | 35.8 | 71.9 | 080/50 | 1006.0 |
OOCL Fair | 30/1800 | 32.0 | 75.0 | 260/55 | 1006.0 |
Inspiration | 30/2100 | 35.6 | 72.6 | 090/55 | 1002.5 |
Barbet Arrow | 31/1200 | 32.5 | 71.5 | 240/40 | 1009.2 |
Stonewall Jackson | 31/1200 | 33.5 | 71.7 | 230/55 | 1003.5 |
SealandPerformance | 31/1200 | 35.1 | 70.1 | 160/45 | 1005.0 |
Barbet Arrow | 31/1800 | 32.4 | 72.3 | 250/40 | 1015.0 |
Edyth L. | 31/1800 | 34.8 | 75.1 | 310/55 | 1005.7 |
Stonewall Jackson | 31/1800 | 33.4 | 72.7 | 250/45 | 1007.0 |
Sealand Performance | 31/1800 | 33.7 | 69.8 | 230/40 | 1009.5 |
Stonewall Jackson | 02/0000 | 33.5 | 75.1 | 300/36 | 1010.0 |
Trojan Star | 02/0000 | 36.8 | 70.7 | 110/38 | 1010.1 |
V2PE1 | 02/0600 | 33.9 | 72.2 | 220/40 | 1008.0 |
Shanghai Senator | 02/0900 | 37.6 | 75.1 | 040/35 | 1011.0 |
V2PE1 | 02/1200 | 35.0 | 72.1 | 200/43 | 1005.2 |
OOCL Friendship | 02/1800 | 34.1 | 74.7 | 300/45 | 999.2 |
V2PE1 | 02/1800 | 35.6 | 72.9 | 140/42 | 1004.5 |
OOCL Friendship | 02/2100 | 34.1 | 73.5 | 200/45 | 993.6 |
V2PE1 | 03/0600 | 36.3 | 75.3 | 040/40 | 1010.5 |
Chemical Pioneer | 03/1500 | 34.3 | 76.3 | 320/40 | 1004.7 |
Chemical Pioneer | 03/1800 | 34.7 | 75.8 | 340/35 | 1004.7 |
Hoegh Dene | 04/0600 | 33.1 | 77.3 | 100/39 | 1005.3 |
Hoegh Dene | 04/1200 | 33.8 | 76.4 | 360/37 | 1000.0 |
Hoegh Dene | 04/1500 | 34.1 | 76.0 | 110/39 | 992.5 |
Hoegh Dene | 04/1800 | 34.4 | 75.6 | 150/40 | 987.3 |
Mette Maersk | 04/1800 | 35.4 | 74.4 | 110/45 | 1002.9 |
Mette Maersk | 04/2100 | 35.8 | 73.6 | 120/37 | N/A |
Hoegh Dene | 05/0000 | 35.5 | 75.0 | 140/35 | 1003.8 |
Table 2b. Eleven day rainfall totals ending at 1200 UTC 8 September 1999. Data
courtesy of the National Climatic Data Center
Station |
Rainfall (in) |
Station |
Rainfall (in) |
North Carolina |
Aurora | 10.68 | Greenville | 7.66 |
Jacksonville | 10.54 | Edenton | 7.33 |
Cherry Point | 10.18 | Wilsonville | 7.11 |
Hatteras | 9.30 | Enfield | 7.01 |
Apex | 8.87 | Kinston | 6.80 |
Raleigh/Durham | 8.46 | Rougemount | 6.69 |
Elizabeth City | 8.17 | Rocky Mount | 6.53 |
Goldsboro (GSB) | 8.04 | Butner | 6.50 |
Goldsboro | 7.76 | Arcola | 6.34 |
Neuse | 7.72 | New Bern | 6.09 |
Wilson | 7.69 | Oxford | 6.07 |
Pennsylvania |
Lochiel | 7.23 | Elimsport | 6.90 |
Williamsport | 7.00 | Loyalsockville | 6.90 |
South Carolina |
Myrtle Beach | 6.02 | | |
Virginia |
Allisonia | 13.82 | Fincastle (DAEV2) | 7.03 |
Buchanan | 12.91 | Mauretown | 7.00 |
Front Royal (HOGV2) | 12.86 | Lovingston (LOVV2) | 6.87 |
Roanoke (WITV2) | 10.33 | Front Royal (LIMV2) | 6.76 |
Montebello | 9.40 | Lovingston (BRNV2) | 6.68 |
Copper Hill (COPV2) | 8.31 | Strasburg | 6.57 |
Fincastle (TIKV2) | 7.63 | Waynesboro | 6.52 |
Copper Hill (COHV2) | 7.62 | Springcreek | 6.50 |
Alberta | 7.49 | Roanoke (FOTV2) | 6.44 |
Winterpock | 7.33 | South Boston | 6.41 |
Algoma | 7.11 | Glasgow | 6.28 |
Mathews | 7.10 | Pedlar Mills | 6.20 |
Luray | 7.09 | | |
Table 3. Preliminary track forecast evaluation for Hurricane Dennis -
heterogeneous sample. Errors in nautical miles for tropical storm and
hurricane stages with number of forecasts in parentheses. Numbers in
boldface represent forecast which were better than the official forecast.
Forecast Technique |
Period (hours) |
12 | 24 | 36 | 48 | 72 |
CLIP | 44 (46) | 92 (44) | 150 (42) | 209 (40) | 360 (36) |
GFDI | 40 (38) | 75 (36) | 110 (34) | 148 (32) | 213 (29) |
GFDL* | 40 (36) | 69 (34) | 100 (32) | 136 (30) | 209 (27) |
LBAR | 31 (46) | 61 (44) | 99 (42) | 137 (40) | 217 (36) |
AVNI | 53 (42) | 100 (40) | 139 (38) | 175 (35) | 220 (26) |
AVNO* | 46 (40) | 93 (37) | 134 (35) | 163 (32) | 213 (22) |
BAMD | 35 (45) | 65 (44) | 102 (41) | 144 (39) | 212 (35) |
BAMM | 43 (46) | 84 (44) | 128 (42) | 168 (40) | 260 (36) |
BAMS | 56 (46) | 111 (44) | 169 (42) | 230 (40) | 343 (36) |
NGPI | 48 (44) | 76 (42) | 108 (40) | 133 (38) | 184 (30) |
NGPS* | 46 (23) | 77 (22) | 100 (21) | 133 (20) | 173 (16) |
UKMI | 41 (41) | 68 (39) | 96 (38) | 118 (37) | 161 (33) |
UKM* | 33 (23) | 61 (22) | 82 (21) | 106 (20) | 147 (18) |
A90E | 39 (45) | 73 (43) | 100 (41) | 138 (39) | 228 (35) |
A98E | 38 (40) | 73 (38) | 110 (36) | 151 (34) | 240 (30) |
A9UK | 37 (22) | 73 (21) | 108 (20) | 147 (19 ) | 274 (17) |
|
NHC Official | 34 (46) | 63 (44) | 90 (42) | 112 (40) | 160 (36) |
NHC Official 10-Year Average (1989-1998) | 48 (2005) | 89 (1790) | 128 (1595) | 164 (1410) | 242 (1107) |
*Output from these models was unavailable at time of forecast issuance.
Table 4. Watch and warning summary, Hurricane Dennis, 24 August- 7 September 1999.
Date/Time (UTC) |
Action |
Location |
24/1500 | Tropical Storm Warning issued | Bahamas...Turks and Caicos Islands and SE Bahamas |
24/1500 | Tropical Storm Watch issued | Central Bahamas. |
25/0900 | Hurricane Watch and Tropical Storm Warning issued | Central Bahamas. |
25/0900 | Hurricane Watch issued | Northwest Bahamas. |
26/0900 | Tropical Storm Warning discontinued | Bahamas...Turks and Caicos Islands and SE Bahamas. |
26/1500 | Hurricane Warning issued | Central Bahamas. Northwest Bahamas...Eleuthera and the Abacos. |
27/0300 | Tropical Storm Warning issued | Northwest Bahamas...New Providence, Grand Bahama, and the Berry Islands. |
27/0900 | Hurricane Warning issued | Northwest Bahamas...remainder. |
27/1500 | Hurricane Watch issued | Florida....Sebastian Inlet to Fernandina Beach. |
27/1500 | Hurricane Warning discontinued | Central Bahamas...including Andros and New Providence Islands. |
27/2100 | Tropical Storm Warning issued | Florida...Sebastian Inlet to Flagler Beach. |
28/0900 | Hurricane Warning discontinued | Bahamas...Eleuthera and the Berry Islands. |
28/2100 | Hurricane Warning discontinued | Bahamas...Abacos and Grand Bahama Islands. |
29/0300 | Hurricane Watch issued | N of Savannah, GA to Surf City, NC. |
29/0300 | Hurricane Watch discontinued | Florida...Sebastian Inlet to Fernandina Beach. |
29/0900 | Tropical Storm Warning issued | N of Savannah, GA to Surf City, NC. |
29/0900 | Hurricane Watch issued | North Carolina...Surf City to Cape Hatteras. |
29/1500 | Tropical Storm Warning issued | North Carolina...Surf City to Cape Hatteras. |
29/1500 | Tropical Storm Watch issued | N of Cape Hatteras to Cape Charles Light, VA. |
29/2100 | Hurricane Watch upgraded to Hurricane Warning | Little River Inlet, SC to Oregon Inlet, NC...including Pamlico Sound. |
29/2100 | Tropical Storm Warning issued | Oregon Inlet, NC to Chincoteague, VA...including Abermarle Sound and southern Chesapeake Bay south of New Point Comfort. |
30/0300 | Hurricane Watch and Tropical Storm Warning discontinued | Edisto Beach, SC to Savannah, GA. |
30/0900 | Hurricane Watch upgraded to Hurricane Warning | Oregon Inlet, NC to North Carolina/Virginia border. |
30/0900 | Gale Warning issued | Chincoteague, VA to Cape Henlopen, DE. |
30/0900 | Hurricane Watch and Tropical Storm Warning discontinued | N of Savannah, GA to Little River Inlet, SC. |
30/2100 | Hurricane Warning discontinued | South of Cape Lookout, NC to Little River Inlet, SC. |
31/0300 | Hurricane Warning downgraded to Tropical Storm Warning | Cape Lookout, NC to NC/VA border. |
31/0900 | Gale Warning issued | Cape Henlopen, DE to Great Egg Inlet, NJ. |
01/0300 | Tropical Storm Warning and a Hurricane Watch issued | Surf City, NC to Chincoteague, VA...including Pamlico and Ablemarle Sounds and southern Chesapeake Bay south of New Point Comfort. |
01/1500 | Hurricane Watch discontinued | Surf City, NC to Chincoteague, VA...including Pamlico and Ablemarle Sounds and southern Chesapeake Bay south of New Point Comfort. |
02/0600 | Gale Warning discontinued | Fenwick Island, DE to Cape Henlopen, DE. |
02/0600 | Gale Warning issued | Chincoteague, VA to Fenwick Island, DE. |
02/1500 | Tropical Storm Warning discontinued | North of Cape Charles Light, VA to Chincoteague, VA South of Cape Lookout, NC to Surf City, NC. |
02/2100 | Tropical Storm Warning discontinued | Southern Chesapeake Bay south of New Point Comfort. |
03/0300 | Tropical Storm Warning discontinued | Cape Charles Light, VA to NC/VA border. |
03/0900 | Tropical Storm Warning discontinued | Oregon Inlet, NC to NC/VA border. |
03/2100 | Tropical Storm Watch issued | Oregon Inlet, NC to NC/VA border...including Ablemarle Sound. Cape Lookout, NC to Surf City, NC. |
04/0900 | Tropical Storm Warning issued | N of Oregon Inlet, NC to the NC/VA border...including Ablemarle Sound. S of Cape Lookout, NC to Surf City, NC. |
04/1500 | Tropical Storm Warning upgraded to Hurricane Warning | NC/VA border to Surf City, NC...including Pamlico and Ablemarle Sounds. |
04/1500 | Tropical Storm Warning issued | N of NC/VA border to Chincoteague, VA...including Chesapeake Bay south of Smith Point. |
04/2100 | Tropical Storm Warning issued | Entire Chesapeake Bay...including the Tidal Potomac. |
04/2100 | Gale Warning issued | N of Chincoteague, VA to Great Egg Inlet, NJ. |
05/0100 | Hurricane Warning downgraded to Tropical Storm Warning | NC/VA border to Surf City, NC...including Pamlico and Ablemarle Sounds. |
05/0900 | Tropical Storm Warning discontinued | NC/VA border to Surf City, NC...including Pamlico and Ablemarle Sounds. |