000 WTPZ44 KNHC 160232 TCDEP4 TROPICAL STORM CARLOS DISCUSSION NUMBER 25 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042009 800 PM PDT WED JUL 15 2009 WESTERLY VERTICAL WIND SHEAR CONTINUES TO AFFECT CARLOS...WITH OCCASIONAL PUFFS OF CONVECTION OCCURRING JUST EAST OF THE CENTER. THERE IS ALSO SOME POORLY-DEFINED OUTER BANDING IN THE SOUTHEASTERN SEMICIRCLE. WHILE SATELLITE INTENSITY ESTIMATES FROM SAB AND TAFB REMAIN 55 KT...THE RAGGED APPEARANCE OF CARLOS SUGGESTS IT HAS WEAKENED SINCE 18Z. THE INITIAL INTENSITY IS REDUCED TO A SOMEWHAT UNCERTAIN 45 KT. THE INITIAL MOTION IS NOW 275/11. OTHER THAN THAT...THERE IS LITTLE CHANGE IN THE FORECAST GUIDANCE OR REASONING SINCE THE LAST PACKAGE. CARLOS IS IN EASTERLY FLOW SOUTH OF A LOW/MID-LEVEL RIDGE...AND BY 36 HR IS FORECAST TO BE UNDER NORTHERLY TO NORTHEASTERLY UPPER-LEVEL FLOW. THIS PATTERN SUGGESTS THAT THERE IS LITTLE REASON FOR CARLOS TO GAIN MUCH LATITUDE...ESPECIALLY AS MUCH AS FORECAST BY THE RIGHT-OUTLIERS NOGAPS AND GFDN. THE NEW FORECAST TRACK IS SIMILAR TO THE PREVIOUS FORECAST...AND IT IS IN BEST AGREEMENT WITH THE BAMM...BAMD...AND GFS MODELS. THE INTENSITY FORECAST IS PROBLEMATIC. CARLOS IS EXPECTED TO REMAIN IN 15-20 KT OF SHEAR FOR THE NEXT COUPLE OF DAYS...WITH THE SHEAR DIRECTION LIKELY TO CHANGE FROM WESTERLY TO NORTHERLY DURING THAT TIME. THIS IS ENOUGH SHEAR TO HAVE AN IMPACT ON A CYCLONE AS SMALL AS CARLOS. THE HWRF FORECASTS THE CYCLONE TO DISSIPATE AFTER 72 HR...WHILE THE OTHER INTENSITY GUIDANCE HOLDS ON TO IT THROUGH 120 HR. BASED ON THIS...THE INTENSITY FORECAST CALLS FOR CARLOS TO CONTINUE TO WEAKEN FOR 24-36 HR AND THEN PERSIST THROUGH 120 HR IN BEST AGREEMENT WITH THE LGEM MODEL. ALTERNATE SCENARIOS ARE THAT THE SMALL CIRCULATION DECAYS TO A TROUGH...OR THAT IT GETS ABSORBED BY A LARGER ITCZ DISTURBANCE TO THE SOUTHWEST. EITHER OF THESE COULD HAPPEN IN THE NEXT DAY OR TWO. FORECAST POSITIONS AND MAX WINDS INITIAL 16/0300Z 10.2N 132.0W 45 KT 12HR VT 16/1200Z 10.3N 133.5W 35 KT 24HR VT 17/0000Z 10.3N 135.6W 30 KT 36HR VT 17/1200Z 10.3N 137.8W 30 KT 48HR VT 18/0000Z 10.4N 140.4W 30 KT 72HR VT 19/0000Z 10.5N 146.0W 30 KT 96HR VT 20/0000Z 10.0N 152.0W 25 KT 120HR VT 21/0000Z 10.0N 158.0W 25 KT $$ FORECASTER BEVEN