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Remnants of ALLISON Advisory Number 52
 
Issued 09:00Z Jun 19, 2001
 
Advisory Selection
View advisory number:  52   51   50   49   48   47   46   45   44   43   42   41   40   39   38   37   36   35   34   33   32   31   30   29   28   
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STORM SUMMARY NUMBER 52 FOR THE HISTORY OF "ALLISON"...RETRANSMITTED...
NATIONAL CENTERS FOR ENVIRONMENTAL PREDICTION
HYDROMETEOROLOGICAL PREDICTION CENTER...NWS...CAMP SPRINGS MD
753 AM EDT WED JUN 20 2001

...EXTRAORDINARY FLOODS FROM A TYPICAL TROPICAL STORM...

AS THE LOW THAT WAS ONCE ALLISON PASSES SOUTH OF CAPE RACE NEWFOUNDLAND...IT IS
TIME TO REFLECT ON THE GREAT IMPACT ALLISON HAD ON THE SOUTHERN AND EASTERN
UNITED STATES OVER THE TWO WEEK PERIOD FROM JUNE 4TH THROUGH THE 18TH. WHILE THE
CYCLONE WAS FAIRLY SMALL IN AREAL COVERAGE...IT REMAINED CLOSE ENOUGH TO THE
GULF OF MEXICO AND ATLANTIC TO FEED OFF THE MOISTURE AND WARMTH OF THOSE WATER
BODIES...ALLOWING THE SYSTEM TO SURVIVE LARGE PERIODS OF TIME OVER LAND...AND MORE
IMPORTANTLY...TO BECOME AN EFFICIENT RAIN PRODUCER.

THE LIFE CYCLE OF ALLISON WAS SPURRED BY A TROPICAL WAVE THAT HAD MOVED OFF THE
COAST OF AFRICA ON MAY 21ST. IT TRACKED WESTWARD ACROSS THE ATLANTIC
OCEAN...REACHING THE WESTERN CARIBBEAN ON THE 29TH... THEN CROSSED INTO THE
NORTHEAST PACIFIC JUNE 1ST. A LOW LEVEL CIRCULATION FORMED ALONG THE TROPICAL
WAVE SOUTH-SOUTHEAST OF VERA CRUZ ON THE 3RD...THEN MOVED QUICKLY INTO SOUTHEAST
MEXICO STEERED BY DEEP SOUTHWESTERLY FLOW. IT MOVED INTO THE BAY OF CAMPECHE
LATE ON THE 4TH AS AN AREA OF THUNDERSTORMS...AND WAS GUIDED BY A NEARBY UPPER
LEVEL LOW TOWARDS THE NORTH-NORTHWEST THROUGH THE WESTERN GULF OF MEXICO. 

THE AREA OF THUNDERSTORMS BECAME INCREASINGLY ORGANIZED...SO MUCH SO THAT
RECONNAISSANCE AIRCRAFT ALONG WITH SHIP AND BUOY REPORTS INDICATED THE
FORMATION OF A TROPICAL STORM WHILE ONLY 80 MILES OFF THE COAST OF GALVESTON
DURING THE AFTERNOON OF THE 5TH. THIS PROMPTED EVACUATIONS OF THE WEST END OF
GALVESTON ISLAND...AN AREA NOT PROTECTED BY THE LEGENDARY SEAWALL WHICH WAS
BUILT AFTER THE GALVESTON HURRICANE OF 1900.

INITIALLY STEERED BY THE SUBTROPICAL RIDGE CENTERED EAST OF FLORIDA...THE CYCLONE
MOVED NORTHWARD...MAKING LANDFALL ON THE EAST END OF GALVESTON ISLAND TEXAS
DURING THE EVENING OF THE 5TH. THE HIGHEST WINDS REPORTED ON LAND WERE TO THE
NORTHEAST OF THE CENTER IN THE AREA WITH THE TIGHTEST PRESSURE GRADIENT. AT SEA
RIM STATE PARK...NEAR THE COAST OF WESTERN JEFFERSON COUNTY IN SOUTHEAST TEXAS...
SUSTAINED WINDS REACHED 48 MPH AT 9:50 AM CDT ON THE 6TH...AND GUSTS PEAKED AT 61 MPH
AT 9:42 AM CDT. TROPICAL STORM FORCE WINDS WERE REPORTED FROM GALVESTON
EASTWARD TO THE SABINE RIVER DURING THE NIGHT OF THE 5TH AND THE MORNING OF THE 6TH.
THEREAFTER... THE CYCLONE WEAKENED TO A TROPICAL DEPRESSION ...AND THE HURRICANE
CENTER HANDED THE RESPONSIBILITY OF THE ADVISORIES OVER TO THE
HYDROMETEOROLOGICAL PREDICTION CENTER IN CAMP SPRINGS MARYLAND IN THE FORM OF
STORM SUMMARIES... STANDARD PROCEDURE WHEN A DEPRESSION DRIFTS INLAND.

ALLISON DRIFTED AS FAR INLAND AS LUFKIN TEXAS DURING THE MORNING OF THE
7TH...DROPPING LARGE QUANTITIES OF RAIN ALONG AND EAST OF ITS PATH. MUCH OF
SOUTHEAST TEXAS AND SOUTH CENTRAL LOUISIANA HAD ALREADY RECEIVED OVER 10 INCHES
OF RAIN BY THE MORNING OF THE 8TH. IN SOUTH CENTRAL LOUISIANA...MUCH OF THIS RAIN
FELL WITHIN A TWELVE HOUR PERIOD ON THE 6TH...FLOODING MANY HOMES IN LAFAYETTE...
IBERIA... ST MARY... AND VERMILLION PARISHES. DEEP WATER SUBSEQUENTLY SUBMERGED US
HIGHWAY 90 IN THIS REGION FOR OVER 12 HOURS. THIBODAUX LOUISIANA WENT UNDERWATER
WHEN 15.16 INCHES OF RAIN FELL IN THE 24 HOUR PERIOD ENDING THE MORNING OF THE 7TH.

DURING THE NIGHT OF THE 6TH/ 7TH...HEAVY RAINS DELUGED NORTHWEST JEFFERSON AND
ORANGE COUNTIES IN SOUTHEAST TEXAS WHEN 6-10 INCHES OF RAIN FELL IN LESS THAN FIVE
HOURS. SEVERAL HOMES IN CHINA...BEAUMONT...NOME...AND VIDOR TEXAS SAW FLOOD
WATERS INVADE WHILE NUMEROUS STREETS WERE CLOSED DUE TO FLOOD WATERS THAT
STALLED HUNDREDS OF CARS IN THE REGION. FLOODING HAD ALREADY BEGUN IN HOUSTON
...BUT THE WORST WAS YET TO COME.

ON THE MORNING OF THE 7TH...THE SUBTROPICAL HIGH OFF FLORIDA WEAKENED AND DRIFTED
TO THE SOUTH...WHILE A HIGH PRESSURE RIDGE OVER NEW MEXICO WAS INTENSIFYING. THIS
CAUSED THE CYCLONE TO TRANSCRIBE A CLOCKWISE LOOP THAT MORNING...AND THEN MOVE
TO THE SOUTHWEST. THIS BROUGHT MORE RAINFALL TO LOUISIANA AND TEXAS OVER THE
NEXT COUPLE DAYS WHILE THE DEPRESSION AMBLED BACK TOWARDS THE COAST. ALTHOUGH
THE MAIN THREAT FROM ALLISON WAS HEAVY RAINS... TORNADOES DID TOUCHDOWN
NORTHWEST OF ZACHARY IN EAST BATON ROUGE PARISH DURING THE EARLY MORNING OF THE
7TH... WELL TO THE EAST OF THE CENTER. ONE PERSON WAS KILLED WHEN A TREE FELL ONTO
HIS VEHICLE.

AS THE CENTER APPROACHED HOUSTON FOR A SECOND TIME ON THE 8TH... RAIN INTENSIFIED
ACROSS SOUTHEAST TEXAS. CONROE MEASURED 8.23 INCHES DURING A SIX HOUR PERIOD ON
THE AFTERNOON OF THE 8TH. STILL HEAVIER RAINS WERE MOVING ACROSS THE HOUSTON
AREA...OVER 20 INCHES OF RAIN FELL WITHIN A TWELVE HOUR PERIOD. A VAST AREA OF
HOUSTON WAS SUBMERGED BY A SECOND ONSLAUGHT OF HEAVY RAIN WITHIN SIX
DAYS...BUFFALO BAYOU AND GREENS BAYOU FLOODED SEVERELY. ALLISON TURNED OUT TO
BE THE FLOOD OF RECORD FOR THE HOUSTON METROPOLITAN AREA. PORTIONS OF US
HIGHWAY 59 AND INTERSTATE 10 WERE DEEPLY SUBMERGED...ONLY THE TOPS OF SEMI-
TRACTOR TRAILERS WERE VISIBLE ON THOSE MAJOR ROADWAYS. FLOODING OF SIMILAR
MAGNITUDE WAS OCCURRING IN THE BEAUMONT AREA AS WELL. THE LATEST COUNT OF THOSE
THAT PERISHED IN THE FLOOD WAS 22 FROM THE HOUSTON AREA.

THE HIGHEST STORM TOTAL REPORTED FROM TEXAS WAS 36.99 INCHES AT THE PORT OF
HOUSTON. AMELIA (1978)...CLAUDETTE (1979)...AND THE UNNAMED HURRICANE OF SEPTEMBER
1921 REMAIN THE THREE WETTEST TROPICAL CYCLONES IN TEXAS HISTORY. BELOW IS A LIST OF
THE TOP TEN AMOUNTS:

AMOUNT    LOCATION                          STORM NAME          DATES
46.00"    BLUFF                             AMELIA         8/01-04/1978
45.00"    ALVIN COOP SITE                   CLAUDETTE      7/24-27/1979
40.00"    THRALL                            UNNAMED HU     9/07-11/1921
36.99"    PORT OF HOUSTON                   ALLISON        6/05-11/2001
36.40"    WILLIAMSON CTY                    UNNAMED HU     9/09/1921
35.67"    GREENS BAYOU                      ALLISON        6/05-11/2001
33.00"    WESTHEIMER, KIRBY (HOUSTON)       ALLISON        6/05-11/2001
32.99"    HUNTING BAYOU AT I-10 (HOUSTON)   ALLISON        6/05-11/2001
32.00"    ALBANY                            AMELIA         8/01-04/1978
30.07"    ALVIN NWS SITE                    CLAUDETTE      7/24-27/1979

THE SITUATION WAS NOT MUCH BETTER FOR THE BAYOU STATE. HEAVY RAINS BEGAN ON THE
5TH AND CONTINUED THROUGH THE 11TH. THE CENTER FINALLY EXITED THE TEXAS COAST NEAR
PALACIOS ON THE EVENING OF THE 9TH. WHEN IT EMERGED BACK INTO THE GULF OF MEXICO...IT
BECAME THE FIRST KNOWN TROPICAL CYCLONE TO MAKE LANDFALL IN TEXAS...ONLY TO
EMERGE BACK INTO THE GULF. UPPER LEVEL WESTERLIES ASSOCIATED WITH THE SOUTHERN
FRINGE OF THE SUBTROPICAL JET STREAM GUIDED THE LOW EAST-NORTHEASTWARD... MOVING
INTO THE MARSHES/BAYOUS OF SOUTHEAST LOUISIANA ON THE MORNING OF THE 11TH.  THE
MAXIMUM AMOUNTS OCCURRED IN THE VERMILION AND ATCHAFALAYA BASINS OF SOUTH
CENTRAL LOUISIANA WHICH SAW HEAVY RAINS EACH DAY FROM THE 5TH THROUGH THE 11TH.
THE HIGHEST AMOUNT REPORTED FROM LOUISIANA WAS 27.55 INCHES AT SALT POINT...IN ST.
MARY PARISH. 

BELOW IS A LIST OF THE TOP TEN TROPICAL CYCLONE-RELATED RAINFALL AMOUNTS IN
LOUISIANA HISTORY...NOTE THE AMOUNTS ARE LOWER THAN THEY ARE FOR TEXAS. THE
HURRICANE OF 1940 REMAINS THE WETTEST TROPICAL CYCLONE IN LOUISIANA HISTORY...
VIRTUALLY FLOODING THE ENTIRE RICE COUNTRY...INCLUDING MANY TOWNS...IN SOUTHWEST
AND SOUTH CENTRAL LOUISIANA.

AMOUNT         LOCATION                 STORM NAME          DATES
33.71"         CROWLEY                  UNNAMED HU          8/6-10/1940
31.66"         ABBEVILLE                UNNAMED HU          8/6-10/1940
29.86"         THIBODAUX                ALLISON             6/05-11/2001
29.65"         LAFAYETTE                UNNAMED HU          8/6-10/1940
COR  29.52"    WINNFIELD                ALLISON             6/26-7/01/1989
27.55"         SALT POINT               ALLISON             6/05-11/2001
22.30"         LOGANSPORT               UNNAMED TS          7/22-26/1933
21.35"         SLIDELL WFO              ALLISON             6/05-11/2001
21.10"         TERRYTOWN                FRANCES             9/10-14/1998
20.96"         MORGAN CITY              ALLISON             6/05-11/2001

IN SOUTHEAST LOUISIANA...THE COMITE RIVER RECORDED ITS THIRD HIGHEST RIVER STAGE ON
RECORD ON THE 9TH...CRESTING AT 29.1 FEET AT COMITE. IN THE AMITE RIVER BASIN AT PORT
VINCENT AND FRENCH SETTLEMENT...THE RIVER PEAKED AT ITS THIRD HIGHEST STAGE ON
RECORD. AMONG ALL RAIN EVENTS THAT HAVE PLAGUED SOUTHEAST LOUISIANA IN THE
PAST...ALLISON IS COMPARABLE TO THE MAY 1995 AND APRIL 1983 FLOOD EVENTS.

ON THE 11TH THE LOW THAT WAS ONCE ALLISON ACCOMPLISHED A RARE TASK...DEVELOPMENT
OVER LAND. THIS WAS MAINLY DUE TO A JET STREAK RIDING ALONG THE SUBTROPICAL JET TO
ITS NORTH AND NORTHEAST ENHANCING ITS OUTFLOW...WHICH IN TURN LED TO A STRONGER
SURFACE LOW. BY 1 AM CDT ON THE 11TH... THE CYCLONE REGAINED GALE-FORCE WINDS WHICH
WERE OVERSPREADING THE MOUTH OF THE MISSISSIPPI RIVER AND THE BARRIER ISLANDS OF
THE MISSISSIPPI COAST. BY 7 AM CDT...AN EYE-LIKE FEATURE DEVELOPED ON RADAR WHILE
THE SYSTEM ENTERED SOUTHWEST MISSISSIPPI. SUSTAINED WINDS INCREASED TO 45
MPH...WITH GUSTS TOWARDS 60 MPH IN ITS MAIN INFLOW BAND EAST OF THE CENTER. AS IT
EDGED FARTHER INLAND THAT AFTERNOON...IT FINALLY WEAKENED AND LOST THE EYE.

SEVERE WEATHER BECAME MORE FREQUENT IN THE VICINITY OF ALLISON DUE TO STRONGER
WINDS ALOFT INTERACTING WITH ITS CIRCULATION. TWO TORNADO TOUCHDOWNS WERE
REPORTED BY THE BILOXI POLICE DEPARTMENT AT 5:35 AM CDT ON THE 11TH. AN F1 TORNADO
TOUCHED DOWN IN GEORGE COUNTY MISSISSIPPI AROUND 7 AM CDT THE 11TH...DESTROYING A
MANUFACTURED HOME AND CAUSING MAJOR DAMAGE TO A TWO-STORY HOME. 

AN F0 TORNADO TOUCHED DOWN IN MOBILE COUNTY ALABAMA AROUND 7:30 AM CDT ON THE
11TH...AND REMAINED ON THE GROUND FOR 2.5 MILES. SEVERAL HOMES SAW DAMAGE WHEN
TREES FELL UPON THEM WHILE OTHER HOUSES SUFFERED ROOF DAMAGE FROM HIGH WINDS.
TWO TORNADOES WERE SPOTTED IN MADISON COUNTY FLORIDA BETWEEN 7:56 AND 9:38 PM
EDT ON THE 11TH...WITH A THIRD TOUCHING DOWN 3 MILES EAST OF TALLAHASSEE AT 11:05 PM
EDT. ON THE AFTERNOON OF THE 12TH...WITNESSES REPORTED SEEING A FUNNEL CLOUD TOUCH
DOWN IN HEPHZIBAH GEORGIA.

HEAVY RAINS FELL ACROSS THE EASTERN GULF COAST AS WELL...BUT WITH MUCH LESS
SEVERITY AS THE LOW WAS MOVING WITH A 13 MPH FORWARD MOVEMENT.  EVEN
SO...GULFPORT MISSISSIPPI RECORDED 11.99 INCHES OF RAIN BY 1 PM ON THE 11TH...MUCH OF IT
IN THE PRECEDING 24 HOURS. BEFORE THE CENTER EMERGED OUT OF MISSISSIPPI...ALLISON'S
MAIN RAIN BAND HAD MOVED EASTWARD TO NEAR TALLAHASSEE FLORIDA... AND THEN
STALLED. DOPPLER RADAR ESTIMATES EXCEEDED TEN INCHES JUST TO THE WEST OF THE
FLORIDA CAPITAL...WITH TALLAHASSEE NETTING 9.86 INCHES BETWEEN THE MORNING OF THE
11TH AND 12TH. 

ALLISON TRACKED OUT OF MISSISSIPPI INTO SOUTHERN ALABAMA ON THE AFTERNOON ON THE
11TH...CONTINUING ITS QUICK EAST-NORTHEAST MOVEMENT. ITS FORWARD MOTION BEGAN TO
SLOW AS A BLOCKING RIDGE OF HIGH PRESSURE WAS SITTING OFF THE COAST OF NEW
ENGLAND...BRINGING THE SYSTEM TO A HALT AS IT WAS NEARING THE ATLANTIC COAST NEAR
WILMINGTON ON THE MORNING OF THE 14TH. 

THE HEAVIEST RAINFALL WITH THE LOW WAS SHIFTING TO ITS NORTHWEST QUADRANT EACH
NIGHT AS IT TRACKED THROUGH THE SOUTHEAST. HEAVY RAINS FELL IN GEORGIA... WHERE
SILOAM PICKED UP 5.75 INCHES IN THE 24 HOUR PERIOD ENDING ON THE MORNING OF THE 13TH.
ON THE 13TH...A LOCAL FIRE DEPARTMENT REPORTED ITS RAIN GAGE OVERFLOWED WITH OVER
12 INCHES OF RAIN IN 14 HOURS JUST TO THE EAST OF COLUMBIA SOUTH CAROLINA.

SEVERE WEATHER BROKE OUT IN GEORGIA...SOUTH CAROLINA...AND SOUTHERN NORTH
CAROLINA ON THE 13TH AND 14TH. HAIL FELL IN MOUNTAIN REST... LANDRUM...AND ANDERSON
SOUTH CAROLINA. SQUALLY WINDS DOWNED TREES AND POWER LINES THROUGHOUT THE
REGION. DANGEROUS RIP CURRENTS DEVELOPED IN THE OUTER BANKS OF NORTH CAROLINA AS
THE WINDS BECAME PERPENDICULAR TO THE SHORE.

AS THE SYSTEM SLOWED TO A CRAWL IN NORTH CAROLINA...FLOODING BECAME A MAJOR
PROBLEM IN THAT STATE. EVEN AFTER ALLISON BEGAN MOVING NORTH-NORTHEAST AROUND
THE HIGH PRESSURE RIDGE TO ITS EAST...INTO VIRGINIA...THE RAIN KEPT ON FALLING ACROSS
NORTHEAST NORTH CAROLINA IN ITS SOUTHWESTERN QUADRANT ...PROLONGING THE FLOOD
EVENT INTO THE 16TH. ASKEWVILLE REPORTED 8.50 INCHES OF RAIN WITHIN A 16 HOUR PERIOD
ON THE 15TH. FLOODED ROADS WERE REPORTED IN ITS VICINITY...ALONG WITH WATER
INVADING CARS AND AREA HOMES. BETWEEN THE 12TH AND THE 16TH...THE DOPPLER RADAR IN
MOREHEAD CITY ESTIMATED UP TO 21 INCHES OF RAIN FELL ACROSS THE BERTIE/HERTFORD
COUNTY BORDER...AS WELL AS HALIFAX AND MARTIN COUNTIES IN NORTH CAROLINA.

AS THE CENTER MOVED NORTH-NORTHEAST ALONG THE EASTERN EDGE OF THE DELMARVA
PENINSULA...A COLD FRONT MOVED IN FROM THE WEST. THIS ALLOWED MOISTURE FROM
ALLISON TO POOL ALONG THE FRONT TO THE NORTH OF THE CENTER...SETTING THE STAGE FOR
HEAVY RAINS ACROSS THE NORTHERN MID-ATLANTIC AND SOUTHERN NEW ENGLAND.
SOUTHEAST PENNSYLVANIA SAW TORRENTS OF RAIN DURING THE AFTERNOON AND EVENING
OF THE 16TH...WILLOW GROVE NAVAL AIR STATION RECORDED 8.47 INCHES OF RAIN MAINLY IN
THE EIGHT HOUR PERIOD BETWEEN 2 AND 10 PM EDT. ULTIMATELY...WILLOW GROVE RECEIVED
10.16 INCHES WHILE CHANFONT RECORDED 10.17 INCHES FOR THE 24 HOUR PERIOD ENDING THE
MORNING OF THE 17TH.

AS THE SYSTEM PARALLELED THE COAST OFF THE NORTHEAST...RAINFALL AMOUNTS OF 2 TO 3
INCHES SOAKED PORTIONS OF NEW JERSEY...SOUTHERN NEW YORK...CONNECTICUT...
MASSACHUSETTS...AND RHODE ISLAND. THE LAST OF THE RAIN ASSOCIATED WITH ALLISON
LEFT EASTERN MAINE DURING THE EARLY MORNING OF THE 18TH AS THE CYCLONE
ACCELERATED OFF TO THE EAST-NORTHEAST. ACCORDING TO PRESS REPORTS...43 PEOPLE
PERISHED DURING ALLISON...MAINLY DUE TO FLOODING. DAMAGE TO THE HOUSTON AREA
ALONE TOTALED 2.14 BILLION DOLLARS.

THE INFORMATION IN THIS FINAL STORM SUMMARY WAS MADE UP OF A COMPILATION OF
STORM AND RAINFALL SUMMARIES FROM THE HOUSTON/ GALVESTON...LAKE
CHARLES...SLIDELL...MOBILE...WAKEFIELD... AND MOUNT HOLLY OFFICES...IN ADDITION TO THE
PREVIOUS 47 STORM SUMMARIES ISSUED BY THIS OFFICE. THE NATIONAL HURRICANE CENTER
PROVIDED AN EARLY VERSION OF ITS PRELIMINARY STORM REPORT FOR REFERENCE IN
PROVIDING A HISTORY OF ALLISON'S FORMATION.

THIS WILL BE THE LAST STORM SUMMARY TO BE ISSUED ON ALLISON FROM THE
HYDROMETEOROLOGICAL PREDICTION CENTER.

ROTH/FORECAST OPERATIONS BRANCH