000
FGUS62 KALR 051803 RRA
ESGALR

HYDROLOGIC VULNERABILITY ASSESSMENT
NWS SOUTHEAST RIVER FORECAST CENTER, ATLANTA, GA
2:00 PM EDT FRI SEP 05 2008

...FAY, HANNA, AND POSSIBLY IKE CAUSING HYDROLOGIC CONCERNS ACROSS 
THE SOUTHEAST U.S. ...

A COMPLEX HYDROLOGIC SITUATION EXISTS ACROSS THE SOUTHEAST U.S., 
WITH AREAS IN DESPERATE NEED OF RAINFALL ADJACENT TO AREAS 
VULNERABLE TO FLOODING.

FAY PRODUCED RAINFALL THAT RESULTED IN MAJOR TO RECORD FLOODING OVER 
PARTS OF FLORIDA.  THE MIDDLE ST. JOHNS RIVER REMAINS IN SIGNIFICANT 
FLOOD, WITH LITTLE CHANGE OVER THE NEXT 5 DAYS.  THE COMMUNITIES OF 
GENEVA, SANFORD, AND DELAND ARE EXPERIENCING, OR ARE FORECAST TO 
EXPERIENCE, MAJOR FLOODING.

OVERALL, DUE TO T.S. FAY, MUCH OF FLORIDA REMAINS HIGHLY VULNERABLE TO 
FLOODING SHOULD ANY TROPICAL SYSTEMS MOVE INTO THE REGION.  THIS 
"HYDROLOGIC VULNERABILITY WINDOW" WITHIN FLORIDA COULD VERY WELL 
PERSIST THROUGH THE REMAINDER OF THE HURRICANE SEASON.

INLAND-MOVING TROPICAL SYSTEMS ALMOST ALWAYS PRODUCE HEAVY RAINFALL, 
AND HANNA WILL BE NO EXCEPTION.  FORTUNATELY, THE FAST FORWARD SPEED 
OF HANNA WILL TEND TO SOMEWHAT LIMIT OVERALL RAINFALL AMOUNTS.  
RAINFALL IN THE 3- TO 5-INCH (BASIN-AVERAGE) RANGE IS EXPECTED.  
LOCALLY HEAVIER AMOUNTS ARE POSSIBLE, ESPECIALLY NEAR WHERE HANNA 
MAKES LANDFALL.  POINT VALUES COULD EXCEED 8 INCHES.  HEAVIEST 
RAINFALL IS FORECAST OVER THE EASTERN THIRD OF NORTH CAROLINA AND 
VIRGINIA AND NORTHWARD.  

AFFECTED AREAS ARE CURRENTLY AT SUMMERTIME BASE FLOW AND CAN HANDLE 
ABOUT 4 INCHES OF RAINFALL BEFORE SIGNIFICANT FLOODING IS A CONCERN.

IN THE SERFC'S AREA -- THE CHOWAN RIVER BASIN COULD SEE SIGNIFICANT 
RISES.  THERE IS THE POSSIBILITY FOR MINOR FLOODING ON THE NOTTOWAY 
RIVER NEAR STONY CREEK AND RAWLINGS, VA., AND ON THE MEHERRIN RIVER 
AT LAWRENCEVILLE, VA.

EVEN THOUGH SIGNIFICANT MAIN STEM RIVER FLOODING WILL BE LIMITED DUE 
TO HANNA'S FAST MOVEMENT, OTHER HYDROLOGIC IMPACTS COULD STILL OCCUR.

- COASTAL INUNDATION AND FLOODING WILL STILL BE A CONCERN.
- FLOODING OF SMALLER CREEKS, TRIBUTARIES, AND DRAINAGES CAN BE      
EXPECTED.
- FLASH FLOODING IS A POSSIBILITY.
- URBAN FLOODING AND FLOODING OF POORLY-DRAINED LOCATIONS IS LIKELY.

KEEP INFORMED ON SPECIFIC DETAILS THROUGH PRODUCTS AND INFORMATION 
TRANSMITTED BY YOUR LOCAL NWS OFFICE.

SERFC WATER WATCH TEAM

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