PRELIMINARY POST STORM REPORT...HURRICANE DENNIS

NATIONAL WEATHER SERVICE WAKEFIELD VA

1030 AM EDT WED SEP 08 1999
 

...GENERAL INFORMATION...

HURRICANE AND TROPICAL STORM DENNIS PRODUCED ONE OF THE MOST PROLONGED PERIODS OF TROPICAL CYCLONE RELATED CONDITIONS ACROSS NORTHEAST NORTH CAROLINA AND EASTERN VIRGINIA. THE REGION EXPERIENCED THESE CONDITIONS OVER A WEEK LONG PERIOD FROM AUGUST 30TH THROUGH SEPTEMBER 5TH.

HURRICANE DENNIS INITIALLY APPROACHED THE REGION ON SUNDAY AUGUST 29TH AS A STRONG CATEGORY 2 HURRICANE WITH A MINIMUM CENTRAL PRESSURE OF 962 MILLIBARS AND WINDS OF 105 MILES PER HOUR. DENNIS PASSED WITHIN 75 MILES OF CAPE HATTERAS NORTH CAROLINA DURING THE AFTERNOON OF AUGUST 30TH. THE GRADIENT BETWEEN LARGE HIGH PRESSURE OVER THE GREAT LAKES AND NEW ENGLAND AND DENNIS OFF THE MID-ATLANTIC COAST FROM AUGUST 30TH THROUGH SEPTEMBER 2ND RESULTED IN AN EXTENDED PERIOD OF ONSHORE WINDS...HEAVY SURF AND SEVERE BEACH EROSION OVER THE OUTER BANKS OF NORTH CAROLINA INTO VIRGINIA BEACH.

DENNIS STALLED OR DRIFTED SOUTHWEST OFF THE MID-ATLANTIC COAST BETWEEN AUGUST 31ST AND SEPTEMBER 3RD BEFORE TURNING TO THE NORTHWEST AND FINALLY MAKING LANDFALL NEAR OCRACOKE NORTH CAROLINA AT 500 PM SEPTEMBER 4TH AS A STRONG TROPICAL STORM WITH A CENTRAL PRESSURE OF 981 MILLBARS.

THE ERRATIC MOVEMENT OF DENNIS IN THE MID-ATLANTIC REGION WAS SIMILAR TO THAT OF SEVERAL OTHER TROPICAL SYSTEMS IN THE PAST 30 YEARS. MOST NOTABLY.

HURRICANE GORDON NOVEMBER 11-18, 1994

TROPICAL STORM DAWN SEPTEMBER 4-14, 1972

HURRICANE DORIA SEPTEMBER 7-21, 1967
 

A. HIGHEST WINDS...ALL TIMES IN EDT ON AUGUST 30TH UNLESS OTHERWISE NOTED.

SUSTAINED GUST
 

NORFOLK AIRPORT (ORF) 37 KT/43 MPH 1251 PM 46 KT/53 MPH 117 PM

ELIZABETH CITY CGS (ECG) 34 KT/39 MPH 1254 PM 45 KT/52 MPH 940 AM

PORTSMOUTH $ 29 KT/34 MPH 700 PM 32 KT/37 MPH 700 PM

LANGLEY AFB (LFI) 45 KT/52 MPH 732 PM 66 KT/76 MPH 732 PM *

NEWPORT NEWS (PHF) 28 KT/33 MPH 732 PM 39 KT/45 MPH 731 PM *

FORT EUSTIS (FAF) 21 KT/24 MPH 146 PM 29 KT/34 MPH 1155 PM #

OCEANA NAS

WALLOPS ISLAND 33 KT/38 MPH 117 PM 40 KT/46 MPH 116 PM

ROANOKE RAPIDS 27 KT/31 MPH 814 AM 35 KT/40 MPH 817 AM

* - SEPTEMBER 4TH

# - SEPTEMBER 3RD

$ - ANEMOMETER ELEVATION IS 73 FT/TIME UNKNOWN
 

B. LOWEST PRESSURE...ALL TIMES IN EDT ON SEPTEMBER 5TH UNLESS OTHERWISE NOTED.

NORFOLK AIRPORT (ORF) ALTM 29.71 SLP 1006.1 MB/0151 AM

RICHMOND (RIC) ALTM 29.72 SLP 1006.5 MB/0354 AM

ELIZABETH CITY CGS (ECG) ALTM 29.64 SLP 1003.8 MB/0713 PM *

OCEANA NAS (NTU) ALTM 29.72 SLP 1006.5 MB

NORFOLK NAS (NGU) ALTM 29.72 SLP 1006.5 MB

LANGLEY AFB (LFI) ALTM 29.74 SLP 1007.1 MB

NEWPORT NEWS (PHF) ALTM 29.72 SLP 1006.5 MB

* - SEPTEMBER 4TH
 

C. RAINFALL...(STORM TOTAL FOR 8/29/99 - 9/05/99)

NORFOLK AIRPORT (ORF) 3.30 INCHES

NORFOLK NAS (NGU) 2.85 INCHES

OCEANA NAS (NTU) 2.90 INCHES

NEWPORT NEWS (PHF) 3.23 INCHES

RICHMOND 2.18 INCHES

PORTSMOUTH 5.75 INCHES

ELIZABETH CITY NC 7.01 INCHES

WFO WAKEFIELD 4.59 INCHES

JOHN KERR DAM 3.38 INCHES

STORM TOTAL PRECIPITATION CORRELATED WELL WITH OBSERVED TOTALS ON THE WSR-88D. THE WAKEFIELD WSR-88D UTILIZED THE TROPICAL Z-R FOR PRECIPITATION ESTIMATION DURING HURRICANE DENNIS.
 

D. STORM TIDES...

TIDAL DEPARTURE AT SEWELLS POINT IN NORFOLK WAS AROUND 3.0 FEET ABOVE NORMAL OR 6.0 FEET ABOVE MLLW. THIS RESULTED IN MODERATE COASTAL FLOODING AT THE TIME OF HIGH TIDE AT 12:48 PM IN THE AFTERNOON OF AUGUST 30TH...THIS WATER LEVEL WAS APPROXIMATELY THE SAME LEVEL REACHED DURING
THE PASSAGE OF HURRICANE BONNIE ON AUGUST 27, 1998.  STRONG NORTHERLY WINDS DURING THE PERIOD AUGUST 31ST THROUGH SEPTEMBER 3RD RESULTED IN WATER LEVELS OF AROUND 2 FEET BELOW NORMAL ALONG THE NORTHERN SHORE OF THE ALBEMARLE SOUND. THE SHIFT IN WINDS TO THE SOUTHEAST AS DENNIS MADE LANDFALL ON SEPTEMBER 4TH BROUGHT IN ABOVE NORMAL TIDES.

PASQUOTANK...CAMDEN AND CHOWAN COUNTIES IN NORTH CAROLINA EXPERIENCED APPROXIMATELY A 2 TO 3 FOOT SURGE IN THE ALBEMARLE SOUND WITH SOME FLOODING IN COASTAL SECTIONS OF THOSE COUNTIES. A NUMBER OF ROADS WERE FLOODED IN CAMDEN COUNTY. THE FIRE DEPARTMENT IN CAMDEN COUNTY WAS
INUNDATED FOR A TIME.
 

E. BEACH EROSION...

THE EXTENDED PERIOD OF ONSHORE WINDS AND BATTERING SWELLS FROM DENNIS RESULTED IN LOCALLY SEVERE BEACH EROSION FROM THE SANDBRIDGE AREA OF VIRGINIA BEACH SOUTHWARD THROUGH THE CURRITUCK COUNTY PORTION OF THE OUTER BANKS.
 

F. FLOODING...RIVER FLOODING

THE HEAVIEST RAINFALL FROM HURRICANE DENNIS WAS CONCENTRATED IN NORTHEAST NORTH CAROLINA AND SOUTHEAST VIRGINIA. RADAR BASED ESTIMATES WERE GENERALLY 4 TO 5 INCHES IN SOUTH-CENTRAL AND SOUTHEAST VIRGINIA...INTERIOR NORTHEAST NORTH CAROLINA TO 6 TO 8 INCHES ACROSS THE NORTHERN OUTER BANKS.

THE RAINFALL FROM DENNIS FELL OVER RELATIVELY DRY JAMES AND CHOWAN RIVER BASINS. THUS FAR NO RIVERS WITHIN THE WAKEFIELD VIRGINIA HSA HAVE REACHED FLOOD STAGE. THE NOTTOWAY RIVER AT STONY CREEK WAS WITHIN A FOOT OF FLOOD STAGE AS OF 2:00 PM SEPTEMBER 5TH.
 

G. TORNADOES...

ONLY ONE CONFIRMED TORNADO OCCURRED IN ASSOCIATION WITH HURRICANE DENNIS. A TORNADO RATED AN F2 ON THE FUJITA SCALE TOUCHED DOWN IN THE COLISEUM MALL...MERCURY BOULEVARD AREA IN THE CITY OF HAMPTON IN A THREE BLOCK AREA. THREE APARTMENT COMPLEXES AND AN ASSISTED LIVING FACILITY WERE CONDEMNED. ADDITIONALLY TWO APARTMENT COMPLEXES WERE PARTIALLY CONDEMNED. THERE ARE NO ESTIMATES OF DAMAGE AT THIS TIME.

THIS TORNADO WAS THE STRONGEST TORNADO OBSERVED IN ASSOCIATION WITH A TROPICAL SYSTEM IN THE PAST 5 YEARS WITHIN THE WAKEFIELD WFO COUNTY WARNING AREA.

MANY ROOFS WERE LIFTED OFF BUILDINGS. 10 CARS AND AN 18 WHEEK TRACTOR TRAILER WERE FLIPPED OVER. ONE CAR WAS ROLLED OVER. THIS STORM DID NOT PRODUCE A CONTINUOUS DAMAGE SWATH. SOME AREAS WHERE THE TORNADO DID NOT TOUCH GROUND REPORTED TOPS OF TREES SHEARED OFF.  THERE WERE NUMEROUS INJURIES ASSOCIATED WITH THIS TORNADO. SIX OF THE INJURIES WERE CONSIDERED SERIOUS.
 

H. STORM EFFECTS...

A FEW TREES AND POWER LINES WERE BLOWN DOWN ACROSS NORTHEAST NORTH CAROLINA AND THE IMMEDIATE HAMPTON ROADS AREA...RESULTING IN POWER OUTAGES TO 20000 CUSTOMERS.

HUGH COBB
WFO WAKEFIELD