905 BULLETIN TROPICAL STORM KAREN ADVISORY NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122013 400 AM CDT SAT OCT 05 2013 ...KAREN MOVING NORTH-NORTHWESTWARD TOWARD THE NORTHERN GULF COAST... SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...27.1N 91.3W ABOUT 180 MI...290 KM S OF MORGAN CITY LOUISIANA ABOUT 195 MI...310 KM SW OF THE MOUTH OF THE MISSISSIPPI RIVER MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...NNW OR 330 DEGREES AT 8 MPH...13 KM/H MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... NONE SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * MORGAN CITY LOUISIANA TO THE MOUTH OF THE PEARL RIVER A TROPICAL STORM WATCH IS IN EFFECT FOR... * METROPOLITAN NEW ORLEANS * LAKE MAUREPAS * LAKE PONTCHARTRAIN * EAST OF THE MOUTH OF THE PEARL RIVER TO INDIAN PASS FLORIDA A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS. INTERESTS ELSEWHERE ALONG THE NORTHEASTERN COAST OF THE GULF OF MEXICO SHOULD MONITOR THE PROGRESS OF KAREN. FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 400 AM CDT...0900 UTC...THE CENTER OF TROPICAL STORM KAREN WAS LOCATED NEAR LATITUDE 27.1 NORTH...LONGITUDE 91.3 WEST. KAREN IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 8 MPH...13 KM/H. A TURN TOWARD THE NORTH IS EXPECTED LATER TODAY. A TURN TOWARD THE NORTHEAST IS EXPECTED TONIGHT...AND A NORTHEASTWARD MOTION WITH AN INCREASE IN FORWARD SPEED IS EXPECTED ON SUNDAY. ON THE FORECAST TRACK...THE CENTER OF KAREN IS ANTICIPATED TO BE NEAR THE COAST IN THE TROPICAL STORM WARNING AREA TONIGHT OR SUNDAY MORNING. MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65 KM/H...WITH HIGHER GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 48 HOURS. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 115 MILES...185 KM FROM THE CENTER. THE MINIMUM CENTRAL PRESSURE REPORTED BY AIR FORCE RESERVE AND NOAA HURRICANE HUNTER AIRCRAFT IS 1007 MB...29.74 INCHES. HAZARDS AFFECTING LAND ---------------------- WIND...TROPICAL STORM CONDITIONS ARE EXPECTED WITHIN PORTIONS OF THE WARNING AREA BY THIS AFTERNOON. TROPICAL STORM CONDITIONS ARE POSSIBLE IN PORTIONS OF THE WATCH AREA TONIGHT AND SUNDAY. STORM SURGE...THE COMBINATION OF STORM SURGE AND THE TIDE WILL CAUSE NORMALLY DRY AREAS NEAR THE COAST TO BE FLOODED BY RISING WATERS. THE WATER COULD REACH THE FOLLOWING HEIGHTS ABOVE GROUND IF THE PEAK SURGE OCCURS AT THE TIME OF HIGH TIDE... TERREBONNE BAY TO WEST OF APALACHEE BAY...1 TO 3 FT APALACHEE BAY INCLUDING CEDAR KEY...2 TO 4 FT SOUTH OF APALACHEE BAY TO TAMPA BAY...1 TO 2 FT THE HIGHEST WATER WILL OCCUR ALONG THE IMMEDIATE COAST...WHERE THE SURGE WILL BE ACCOMPANIED BY DANGEROUS WAVES. SURGE-RELATED FLOODING DEPENDS ON THE RELATIVE TIMING OF THE SURGE AND THE TIDAL CYCLE...AND CAN VARY GREATLY OVER SHORT DISTANCES. FOR INFORMATION SPECIFIC TO YOUR AREA...PLEASE SEE PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE. RAINFALL...KAREN IS EXPECTED TO PRODUCE RAINFALL ACCUMULATIONS OF 1 TO 3 INCHES OVER PORTIONS OF THE CENTRAL GULF COAST AND SOUTHEAST UNITED STATES THROUGH MONDAY EVENING...MAINLY NEAR AND TO THE RIGHT OF THE PATH OF THE CENTER. ISOLATED STORM TOTAL AMOUNTS OF 6 INCHES ARE POSSIBLE. NEXT ADVISORY ------------- NEXT INTERMEDIATE ADVISORY...700 AM CDT. NEXT COMPLETE ADVISORY...1000 AM CDT. $$ FORECASTER BEVEN WTNT42 KNHC 050847 TROPICAL STORM KAREN DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122013 400 AM CDT SAT OCT 05 2013 KAREN REMAINS A SHEARED CYCLONE THIS MORNING...WITH THE MAIN CONVECTIVE AREA LOCATED ABOUT 80 N MI SOUTHEAST OF THE CENTER. EARLIER ASCAT OVERPASSES INDICATE WINDS OF AT BEST 35 KT IN THE NORTHEASTERN QUADRANT. THERE ARE RECENT REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT OF STRONGER WINDS IN THE CONVECTION...BUT IT IS UNCLEAR HOW REPRESENTATIVE THESE WINDS ARE. THE INITIAL INTENSITY IS DECREASED TO 35 KT BASED ON THE SCATTEROMETER DATA. KAREN JOGGED A BIT NORTHWESTWARD DURING THE PAST SEVERAL HOURS...BUT IT APPEARS TO HAVE RESUMED A NORTH-NORTHWESTWARD MOTION OF 330/7. THE LOW/MID-LEVEL RIDGE CURRENTLY STEERING KAREN SHOULD WEAKEN TODAY AS A DEEP-LAYER TROUGH AND ASSOCIATED COLD FRONT MOVE EASTWARD THROUGH THE CENTRAL UNITED STATES. THIS SHOULD CAUSE KAREN TO TURN NORTHWARD AND THEN NORTHEASTWARD DURING THE NEXT COUPLE OF DAYS. WHILE THE TRACK GUIDANCE AGREES WITH THIS SCENARIO...THERE REMAINS SOME SPREAD ON THE TIMING OF THE NORTHEASTWARD TURN. THE NEW TRACK FORECAST IS NUDGED NORTHWARD BASED ON THE INITIAL POSITION AND MOTION...AND IT CALLS FOR THE CENTER TO PASS NEAR OR OVER THE MOUTH OF THE MISSISSIPPI RIVER IN 24-36 HOURS...FOLLOWED BY A FINAL LANDFALL IN ALABAMA OR THE WESTERN FLORIDA PANHANDLE BETWEEN 36-48 HOURS. THE NEW FORECAST TRACK LIES NEAR THE CENTER OF THE GUIDANCE ENVELOPE. THERE ARE SEVERAL POSSIBLE SCENARIOS FOR THE LOW CONFIDENCE INTENSITY FORECAST. THE MOST LIKELY SCENARIO...AND THE ONE USED IN THE NEW INTENSITY FORECAST...IS THAT KAREN REMAINS A SHEARED SYSTEM WITH LITTLE CHANGE IN STRENGTH UNTIL FINAL LANDFALL. ONE ALTERNATIVE IS POSSIBLE STRENGTHENING BEFORE LANDFALL DUE TO RE-DEVELOPED CENTRAL CONVECTION. WHILE THE DYNAMICAL MODELS FORECAST UPPER-LEVEL WINDS THAT COULD ALLOW THIS TO HAPPEN...THEY ARE FOR THE MOST PART SHOWING NO SIGNIFICANT STRENGTHENING AS KAREN APPROACHES LANDFALL. A SECOND ALTERNATIVE IS THAT KAREN WEAKENS BELOW TROPICAL STORM STRENGTH BEFORE LANDFALL DUE TO EITHER LACK OF CONVECTION OR THE START OF EXTRATROPICAL TRANSITION. AFTER LANDFALL...KAREN SHOULD WEAKEN AND BECOME EXTRATROPICAL AS IT MERGES WITH THE COLD FRONT. FORECAST POSITIONS AND MAX WINDS INIT 05/0900Z 27.1N 91.3W 35 KT 40 MPH 12H 05/1800Z 27.6N 91.2W 35 KT 40 MPH 24H 06/0600Z 28.4N 90.5W 35 KT 40 MPH 36H 06/1800Z 29.5N 89.2W 35 KT 40 MPH 48H 07/0600Z 31.2N 86.4W 30 KT 35 MPH...INLAND 72H 08/0600Z 35.5N 80.5W 25 KT 30 MPH...POST-TROP/EXTRATROP 96H 09/0600Z...DISSIPATED $$ FORECASTER BEVEN WWWW
Posted on: Sat, 05 Oct 2013 11:25:47 +0000
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