Tropical Storm Hanna 1400L 03 Sept 2008 LT Paul Kemp, NOAA Corps NOAA Desk Officer

Current Satellite Image Center TS Hanna

5 Day Total Rainfall Ending Sunday Evening, Sept. 7

HANNA BEGINNING TO MOVE NORTH-NORTHWESTWARD AT 2:00 PM AST, THE CENTER OF TROPICAL STORM HANNA WAS LOCATED JUST SOUTH OF THE CAICOS ISLANDS. HANNA IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 10 MPH. A TURN TO THE NORTHWEST WITH AN INCREASE IN FORWARD SPEED IS EXPECTED OVER THE NEXT 24 HOURS. ON THE FORECAST TRACK, THE CENTER OF HANNA SHOULD BE MOVING THROUGH OR JUST EAST OF THE CENTRAL AND NORTHWESTERN BAHAMAS OVER THE NEXT COUPLE OF DAYS. MAXIMUM SUSTAINED WINDS ARE NEAR 60 MPH WITH HIGHER GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST TODAY, BUT HANNA COULD REGAIN HURRICANE STRENGTH TOMORROW OR ON FRIDAY. HANNA IS A LARGE TROPICAL CYCLONE. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 290 MILES MAINLY TO THE NORTH OF THE CENTER. THE LATEST MINIMUM CENTRAL PRESSURE REPORTED BY RECONNAISSANCE AIRCRAFT WAS 994 MB INCHES.

Watches and Warnings A HURRICANE WATCH IS IN EFFECT FOR THE NORTHWESTERN BAHAMAS... INCLUDING THE ABACOS...ANDROS ISLAND...BERRY ISLANDS...BIMINI... ELEUTHERA...GRAND BAHAMA ISLAND...AND NEW PROVIDENCE. A HURRICANE WARNING REMAINS IN EFFECT FOR THE CENTRAL BAHAMAS...THE SOUTHEASTERN BAHAMAS...AND THE TURKS AND CAICOS ISLANDS. A TROPICAL STORM WARNING REMAINS IN EFFECT FOR THE NORTHERN COAST OF THE DOMINICAN REPUBLIC FROM PUERTO PLATA WESTWARD TO BAHIA DE MANZANILLO. A TROPICAL STORM WARNING IS ALSO IN EFFECT FOR HAITI FROM THE NORTHERN BORDER WITH THE DOMINICAN REPUBLIC TO PORT-AU- PRINCE. INTERESTS IN THE SOUTHEASTERN UNITED STATES SHOULD MONITOR THE PROGRESS OF HANNA.

Rainfall and Ocean Swells HANNA IS EXPECTED TO PRODUCE RAINFALL TOTALS OF 4 TO 8 INCHES... WITH MAXIMUM ISOLATED AMOUNTS OF 12 INCHES...OVER THE SOUTHEASTERN BAHAMAS...THE TURKS AND CAICOS ISLANDS...AND EASTERN CUBA. RAINFALL TOTALS OF 6 TO 10 INCHES...WITH ISOLATED MAXIMUM AMOUNTS OF UP TO 15 INCHES...ARE POSSIBLE OVER HISPANIOLA THESE RAINS COULD CAUSE LIFE-THREATENING MUD SLIDES AND FLASH FLOODING. COASTAL STORM SURGE FLOODING OF 1 TO 3 FEET ABOVE NORMAL TIDE LEVELS...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...CAN BE EXPECTED IN AREAS OF ONSHORE FLOW WITHIN THE HURRICANE WARNING AREA. MODERATE TO LOCALLY HEAVY RAINFALL IS POSSIBLE ALONG THE EAST COAST OF FLORIDA BY FRIDAY MORNING. SWELLS FROM HANNA ARE EXPECTED TO INCREASE THE RISK OF DANGEROUS RIP CURRENTS ALONG PORTIONS OF THE SOUTHEASTERN UNITED STATES COAST DURING THE NEXT COUPLE OF DAYS.

Technical Discussion THERE HAVE BEEN SOME STRUCTURAL CHANGES WITH HANNA TODAY AS IT INTERACTS WITH THE UPPER-LEVEL LOW MOVING THROUGH THE NORTHWESTERN BAHAMAS. THE WIND FIELD HAS EXPANDED IN THE NORTHERN SEMICIRCLE AND THE LOW-LEVEL CIRCULATION CENTER HAS BECOME LESS WELL DEFINED. VISIBLE IMAGERY SUGGESTS MULTIPLE LOW-LEVEL SWIRLS COMING OUT OF THE DEEP CONVECTION TO THE NORTH OF A MEAN CENTER...AND THE SYSTEM'S CONVECTIVE BANDS ARE WELL REMOVED FROM THE CORE. THE STEERING FLOW SHOULD BECOME BETTER DEFINED OVER THE NEXT HOURS AS THE UPPER LOW MOVES WEST- SOUTHWESTWARD AND MID-LEVEL RIDGING BUILDS IN BEHIND THE LARGE DEEP-LAYER LOW OFF THE UPPER U.S. EAST COAST. WESTERLY SHEAR AND DRY AIR ASSOCIATED WITH THE UPPER LOW WILL INHIBIT DEVELOPMENT IN THE SHORT TERM BUT SHOULD DIMINISH OVER THE NEXT COUPLE OF DAYS...TO BE REPLACED WITH MODERATE SOUTHEASTERLY SHEAR. THIS PATTERN WOULD PERMIT SOME RE-INTENSIFICATION...BUT HANNA WILL NEED TO RECREATE AN INNER CORE IN ORDER TO INTENSIFY SUBSTANTIALLY.