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Preliminary Report
Hurricane Opal
27 September - 5 October 1995

Max Mayfield
National Hurricane Center
29 November 1995


PRELIMINARY REPORTS
Hurricane Allison
Tropical Storm Barry
Tropical Storm Chantal
Tropical Storm Dean
Hurricane Erin
Tropical Depression Six
Hurricane Felix
Tropical Storm Gabrielle
Hurricane Humberto
Hurricane Iris
Tropical Storm Jerry
Tropical Storm Karen
Hurricane Luis
Tropical Depression Fourteen
Hurricane Marilyn
Hurricane Noel
Hurricane Opal
Tropical Storm Pablo
Hurricane Roxanne
Tropical Storm Sebastien
Hurricane Tanya


TROPICAL PREDICTION CENTER/OPAL95 PRELIM

[1995 Atlantic Hurricane Season]

Hurricane Opal made landfall near Pensacola Beach, Florida as a marginal Category 3 hurricane on the Saffir/Simpson Hurricane Scale, causing extensive storm surge damage to the immediate coastal areas of the Florida panhandle. It was the first major hurricane to strike the Florida panhandle since Eloise in 1975 (103K GIF).



a. Synoptic History

Satellite imagery and synoptic analyses indicate that Opal originated from a tropical wave that emerged from the west coast of Africa on 11 September. The wave moved westward across the Atlantic into the western Caribbean Sea by 23 September and merged with a broad area of low pressure centered in the vicinity of 15N° 80°W. The combined system drifted west-northwestward toward the Yucatan peninsula over the following few days without significant development. Deep convection increased near the center of the low and the post-analysis "best track" in Figure 1 (108K GIF) shows that a tropical depression formed about 70 n mi south-southeast of Cozumel, Mexico at 1800 UTC 27 September. Best track position, central pressure and maximum one-minute sustained wind speed are listed for every six hours in Table 1.

Steering currents were weak and the tropical depression moved slowly over the Yucatan peninsula for the following three days. Convective banding increased and ship reports suggest that the depression became Tropical Storm Opal at 1200 UTC 30 September while centered near the north-central coast of the Yucatan peninsula. The storm gradually strengthened and moved slowly westward into the Bay of Campeche.

Air Force Reserve unit aircraft investigating Opal over the southwestern Gulf of Mexico reported that the minimum central pressure steadily dropped. Aircraft reports and satellite estimates suggest that Opal strengthened into a hurricane near 1200 UTC 2 October while centered about 150 n mi west of Merida, Mexico. A banding type eye appeared in satellite imagery later in the day while a large amplitude mid- to upper-level trough moving into the central United States began turning Opal slowly toward the north.

On 3 and 4 October, the hurricane turned toward the north- northeast to northeast and gradually accelerated. During this period, the water temperature beneath the hurricane's circulation was near 28 to 29C, and a large upper-level anticyclone was well established over the Gulf of Mexico. Rapid intensification occurred not only as a result of these favorable environmental conditions on the large scale but, and perhaps more importantly, due to significant changes on a smaller scale within the hurricane's inner core. Opal intensified into a category four hurricane on the Saffir/Simpson Hurricane Scale early on 4 October at which time reconnaissance aircraft reported a small, 10 n mi diameter eye. The minimum central pressure of 916 mb, with maximum sustained surface winds estimated at 130 knots, occurred when the hurricane was centered about 250 n mi south-southwest of Pensacola, Florida near 1000 UTC 4 October. The peak intensity appears to have occurred near the end of an eyewall contraction cycle. Soon thereafter, the small inner eyewall diminished as an outer eyewall became more dominant. The hurricane weakened during this process, but was still a marginal Category 3 hurricane as the center made landfall at Pensacola Beach, Florida near 2200 UTC 4 October. The collapse of the inner eyewall, reduced sea surface temperatures along the Gulf coast and increased upper-level westerlies likely contributed to the weakening.

The hurricane was moving north-northeastward near 20 knots at landfall with the sustained hurricane force winds in the eastern quadrants of the circulation primarily between Pensacola Beach and Cape San Blas. The minimum central pressure at landfall was 942 mb. Maximum sustained surface winds are currently estimated at 100 knots in a narrow swath at the coast near the extreme eastern tip of Choctawhatchee Bay about midway between Destin and Panama City. Although no official reports of surface winds were received within this area, data from reconnaissance aircraft and Doppler radar suggest that the peak winds occurred in this location. It should be emphasized that the strongest winds were in a very limited area and most of the coastal areas of the Florida panhandle experienced winds of a Category 1 or Category 2 hurricane (between 65 and 95 knots). Although the winds were diminishing at the time of landfall, extensive damage due to storm surge and breaking waves occurred over most of the coastal areas of the Florida panhandle.

Opal weakened rapidly after moving inland, becoming a tropical storm over southern Alabama and a tropical depression over southeastern Tennessee. The cyclone was declared extratropical on the best track as it moved northeastward over the Ohio Valley and eastern Great Lakes into southwestern Quebec. The strongest winds occurred well away from the center of the cyclone during the extratropical stage.


b. Meteorological Statistics

Figure 2 (44K GIF) and Figure 3 (51K GIF) show the curves of minimum central pressure and maximum one-minute wind speed, respectively, versus time, along with the observations on which they are based.

U.S. Air Force Reserve aircraft provided a total of 38 operational center fixes during approximately 122 flying hours of reconnaissance on this hurricane. The minimum central pressure reported by aircraft was 916 mb at 0945 UTC 4 October. This represented a 53 mb drop in pressure within 24 hours and a 42 mb fall within about 12 hours. This was a very rapid rate of deepening, but it is not unprecedented. Several western North Pacific typhoons have deepened at an even faster rate. The maximum winds of 152 knots from a flight-level of 700 mb were measured shortly after the 916 mb pressure report. At 2006 UTC, approximately two hours prior to landfall, the aircraft reported 126 knots 59 n mi east of the center. At 2203 UTC, near the time of landfall, the aircraft reported 115 knots 54 n mi east of the center. In addition to the Air Force Reserve reconnaissance, a NOAA aircraft flew a 10 hour research mission at the time of landfall.

A ship with call sign XCKX reported 75 knot winds at 1200 UTC 4 October while located about 90 n mi west-southwest of the hurricane center. Several other ship reports were helpful in defining the extent of tropical storm force winds. Table 2 lists ship reports of at least tropical storm force winds in the vicinity of Opal.

The strongest winds reported by a land station were 73 knots with gusts to 125 knots from Hurlbert Field, Florida. Table 3a lists selected surface observations, and Table 3b lists selected observations made by NOAA's National Data Buoy Center (NDBC) platforms near the path of Opal.

Isolated tornadoes were reported from the Florida panhandle to the mid-Atlantic states. One fatality occurred in Crestview, Florida as a result of a tornado. Another tornado injured several people and severely damaged a number of structures as it swept through Charles, Prince Georges and Anne Arundel Counties in Maryland.

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 from southeastern Mobile Bay and Gulf Shores, Alabama, eastward through the Florida panhandle to Cedar Key, Florida. Still water mark elevations inside of buildings or tide gage maximums, which damp out breaking wave effects and are indicative of the storm surge, ranged from 5 to 14 feet above mean sea level. Outside water marks on buildings or debris lines on sand dunes within 200 feet of the Gulf of Mexico shoreline generally ranged from 10 to 21 feet. For example, the tide gage at the Panama City Beach pier recorded a maximum of approximately 8.3 feet above mean sea level, indicative of storm surge. At the end of the pier a debris line elevation of approximately 18 feet above mean sea level was recorded. Thus, the breaking waves on top of the storm surge added approximately 10 feet. Many structures in this combined storm surge and breaking wave zone that were not elevated high enough suffered major structural damage.

The combination of Opal and a frontal system resulted in heavy rains along the path of the hurricane. Rainfall totals generally ranged from 5 to 10 inches over portions of the Florida panhandle, Alabama and Georgia. Rains in South Carolina averaged 2 to 4 inches while in North Carolina 3 to 5 inches were common. Highlands, North Carolina recorded 8.95 inches and Robinson Creek, North Carolina recorded 9.89 inches. Elsewhere, 1 to 3 inch totals occurred over portions of the northeast U.S. from Maryland northward. These rains have been described as beneficial to areas of the northeast U.S. that had been experiencing a prolonged dry period.


c. Casualty and Damage Statistics

The total number of deaths directly associated with Opal is currently set at 59, and were distributed as follows:


    Guatemala - 31 (from flooding during the developing stages of 
      Opal)
    Mexico  - 19 (from flooding)
    U.S. - 9 including
      Florida (1 from a tornado)
      Alabama (2 from a tree falling on a mobile home)
      Georgia (5 from falling trees)
      North Carolina (1 from a tree falling on a mobile home)

There were no reported deaths due to storm surge flooding, which is remarkable in view of the vulnerable population and extensive salt water damage observed.

The Property Claim Services Division of the American Insurance Services Group preliminary estimate of insured property damage for the United States is $2.1 billion. Considerable uncertainty exists concerning the amount of additional damage due to flood claims, uninsured property damage (including damage to roads and bridges and other government property) and the cost of cleanup. If the estimate of insured property damage proves to be correct, the total damage estimate from Hurricane Opal could reach $3 billion. Without adjustments for inflation, Opal could rank as high as third on the list of costliest twentieth-century U.S. hurricanes. With adjustments for inflation, Opal will likely still be ranked in the top ten on that list.

Most of the severe structural damage occurred at the coastline. The crumbled piers, demolished homes and eroded or submerged highways were primarily a result of the storm surge. In addition, however, strong winds spread damage well inland. Opal downed numerous trees, knocking out power to nearly 2 million people in Florida, Alabama, Georgia and the Carolinas. The Robert Trent Golf Course in Opelika, Alabama lost over 7000 trees during the storm. Many people in Florida were without water for several days.


d. Forecast and Warning Critique

During the time when Opal was of tropical storm or hurricane strength, the mean official track forecast errors of 42 (18 cases), 102 (16 cases), 161 (14 cases), 231 (12 cases) and 326 (8 cases) n mi at 12, 24, 36, 48 and 72 hours respectively were slightly larger than the long-term averages from the previous ten years.

The intensity forecasts showed a negative bias (i.e., intensity was underestimated). The trend for the strengthening of Opal while over water was correctly forecast by the NHC, but the amount of rapid deepening was not anticipated by the official forecasts or by any available objective intensity prediction techniques.

Table 4 lists the coastal watches and warnings issued during Opal. Approximately 31 hours elapsed between the time a hurricane watch was issued and the time of landfall on the Florida panhandle. Approximately 19 hours elapsed between the time of issuance of a hurricane warning was issued and the time of landfall.


 
Table 1. Preliminary best track, Hurricane Opal, 27 September - 6 October 1995.
Date/Time
(UTC)
Position Pressure
(mb)
Wind Speed
(kt)
Stage
Lat. (°N)Lon. (°W)
180019.187.3100425 Trop. Depression
28/000019.487.5100425" "
060019.487.9100425" "
120019.388.2100325" "
180019.388.4100325" "
29/000019.488.4100325" "
060019.588.4100325" "
120019.688.3100325" "
180019.888.2100330" "
30/000020.188.2100230" "
060020.688.3100230" "
120021.188.5100135 Tropical Storm
180021.489.1100040" "
01/000021.389.999445" "
060021.190.798745" "
120020.991.298645" "
180020.891.698550" "
02/000020.791.998455" "
060020.892.198060" "
120021.092.397365Hurricane
180021.292.397265"
03/000021.792.297070"
060022.292.096975"
120022.891.696880"
180023.591.096585"
04/000024.590.1953100"
060025.989.4935110"
120027.388.5919130"
180029.087.7938110"
05/000031.086.895080"
060033.286.297450 Tropical Storm
120035.485.798230 Trop. Depression
180038.583.598640Extratropical
06/000040.582.398940"
060042.080.599140"
120043.378.499735"
180044.576.5100230"
 
04/100026.688.8916130 Minimum Pressure
Landfall:
Pensacola Beach, Florida
04/220030.387.1942100Hurricane



 
Table 2. Ship encounters of 34 knots or
higher associated with Hurricane Opal.
Ship Call
Sign
Date
Mo/Da
Time UTCPositionWind (kt)
Dir/Speed
Pressure
(mb)
Lat°NLon°W
C6CM79/29000022.685.0 120/351006.4
KAFG9/30180020.985.0140/38 1005.7
C6JN10/01180021.994.7340/34 1003.3
C6JN10/02060019.294.5290/40 1000.8
3EWJ910/03120020.686.5140/58 1007.0
C6KE810/03180027.694.4010/34 1003.0
WBVY10/04000027.591.4030/38 997.3
C6KJ510/04060023.186.6160/37 997.5
XCKX10/04060027.288.8110/48 991.0
ELIU210/04120024.784.3160/40 -
SHIP10/04120026.884.7170/46 997.2
XCKX10/04120026.890.1340/75 984.0
KGBE10/04120027.686.0140/48 993.0
VSBZ510/04120028.488.8080/55 983.5
ELIU210/04180024.484.5170/40 1008.5
XCKX10/04180026.790.3290/40 997.0
KGBE10/04180027.485.6210/52 994.6
VSBZ510/04180027.589.3310/47 988.0



 
Table 3a. Hurricane Opal selected surface observations, October 1995.
 Minimum sea-level
pressure
Maximum surface wind
speed (knots)
Storm Surge
(tide height
above normal
(ft))
Rain
(storm total)
(in)
LocationPressure
(mb)
Date/Time
(UTC)
Sustained Peak
Gust
Date/Time
(UTC) *
Louisiana:
New Orleans (MSY)990.904/1953233004/2150  0.34
New Orleans (NEW)991.204/19513041 04/2352 1.17
Mid Lake Ponchartrain Causeway  32 3904/2320  
Mississippi:
Gulfport (GPT)985.404/19473038 04/2147  
Keesler AFB (BIX)984.504/212535 ** 55 **04/1956 3.66
Meridian (MEI)991.605/03032434 04/2335  
Alabama:
Evergreen980.004/2119304304/2115  8.10
Mobile (MOB)978.504/2250335104/2339  7.48
Downtown Mobile  45 5704/2100  
Ft. Rucker (OZR)978.405/005965 ** 85 **05/0024  
Maxwell AFB (MXF)974.105/035541 7805/0327  
Montgomery (MGM)969.405/025641 5505/0245 3.23
Auburn (AUB)980.005/0400244505/0300   
Birmingham (BHM)976.705/06552742 05/0453 3.79
Anniston (ANB)989.005/06312535 05/0335 6.09
Huntsville (HSV)982.405/08563748 05/0627 2.44
Florida:
Pensacola I-10 & East Bay948.204/230243 6304/2247  
Pensacola Airport (FAA)  54 6204/2041  
Pensacola (PNS)   69 04/1930 7.27
Pensacola (NPA)955.004/22255267 04/2043 6.93
Ellyson (near (PNS))       15.45
Hurlburt Field (HRT)960.304/225573 12504/2155 6.64
Fort Walton Beach960.304/2229      
Eglin AFB (VPS)966.5**04/215570 ** 100 **04/2304  
Panama City (PAM)977.704/22065574 04/2252  
Apalachicola (AQQ)991.204/21202851 04/22065-62.56
St. George Island Causeway 6204/2149   
Tallahassee (TLH)993.904/22252845 05/0250 1.25
Tallahassee (FSU Weather Station)995.004/2216  5504/2226  
Turkey Point (TUPF)  3661 04/2047  
Brooksville (BKV)1001.604/2106202804/2115   
New Port Richey1003.504/2116243105/0445   
Tampa (TPA)1002.104/2050213904/1652  1.57
St. Petersburg (PIE)1001.604/20002538 04/1948 1.63
Sarasota1002.304/1848273604/1648 2-42.80
Winter Haven1003.504/2103293604/2341   
Georgia:
Fort Benning (LSF)984.5 **05/0656 40 **50 **05/0555  5.25
Warner Robbins AFB (WRB)994.305/06562944 05/0555 0.99
Atlanta (ATL)987.505/0731274305/0556  6.59
Dobbins AFB (MGE)987.005/075537** 60**05/0608 5.14
Marietta  236005/0734    
Fulton Co. (FTY)       6.22
Peach Tree City (FSC)       7.66

* Time of sustained wind speed unless only gust is given.

** Estimated.


 
Table 3b. Hurricane Opal selected NDBC observations, October 1995.
 Minimum sea-level
pressure
Maximum wind speed
(knots)
PlatformLocationPressure
(mb)
Date/time
(UTC)
average *Peak
gust
Date/time
(UTC)
Grand Isle, LA
C-MAN GDIL1
29.3°N 90.0°W990.004/1900 405204/1400
Southwest Pass, LA
C-MAN BURL1
28.9°N 89.4°W985.404/1700 647504/1700
Dauphin Island, AL
C-MAN DPIA1
30.2°N 88.1°W970.004/2126 536704/2150
Keaton Beach, FL
C-MAN KTNF1
29.8°N 83.6°W998.004/2000 304704/2100
Cedar Key, FL
C-MAN CDRF1
29.1°N 83.0°W1000.204/2100 324604/2300
Buoy 4200125.9°N 89.7°W963.704/0600 536604/1000
Buoy 4200325.9°N 85.9°W992.804/1200 435404/0900
Buoy 4200730.1°N 88.8°W979.504/2100 526804/1900
Buoy 4203628.5°N 84.5°W995.404/2100 354304/1800

*NOAA buoys report an 8-minute average wind and C-MAN stations report a 2-minute average wind.


 
Table 4. Watch and warning summary, Hurricane Opal.
Date/Time
(UTC)
ActionLocation
30/1500Tropical Storm Warning Northeast portion of the Yucatan Peninsula from Cozumel and Cancun to Progreso
01/0300Tropical Storm Warning extended Yucatan Peninsula from Progreso to Celestun
01/2100 Tropical Storm Warning extended Yucatan Peninsula from Progreso to Veracruz
Tropical Storm Warning discontinued Yucatan Peninsula east of Progreso
03/0900Hurricane Watch Morgan City, Louisiana to just west of Pensacola, Florida
03/1500 Hurricane Watch extended Pensacola to the Mouth of the Suwannee River, Florida
Tropical Storm Warning discontinued All portions of the Yucatan Peninsula
03/2100Tropical Storm Warning Morgan City, Louisiana to the Mouth of the Suwannee River, Florida
04/0300Hurricane Warning Mobile, Alabama to Anclote Key, Florida
Tropical Storm Warning extended South of Anclote Key to Venice, Florida
Tropical Storm Warning and Hurricane Watch discontinued West of Grand Isle to Morgan City, Louisiana
04/0900 Hurricane Warning extended Mobile, Alabama westward to the Mouth of the Mississippi River including coastal Mississippi
Tropical Storm Warning and Hurricane Watch extended Grand Isle, Louisiana westward to just east of Morgan City, Louisiana including Metropolitan New Orleans
05/0300 Tropical Storm Warning, Hurricane Warning, and Hurricane Watch discontinuedWest of Mobile, Alabama
05/0500 All remaining coastal Watches and Warnings discontinued  



Brian Maher
Jack Beven

Last updated January 9, 1999