000 WTPZ42 KNHC 220841 TCDEP2 TROPICAL STORM BUD DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP022012 200 AM PDT TUE MAY 22 2012 DURING THE PAST SEVERAL HOURS THE DEPRESSION HAS BEEN PRODUCING A LARGE AREA OF DEEP CONVECTION WITH VERY COLD CLOUD TOPS. RECENT MICROWAVE IMAGERY AND ASCAT DATA INDICATE THAT THE LOW-LEVEL CENTER IS LOCATED NEAR THE EASTERN EDGE OF THE MAIN MASS OF CONVECTION DUE TO MODERATE EASTERLY SHEAR. THE ASCAT DATA SHOWED 30 TO 35 KT WINDS IN A SMALL AREA TO THE NORTHWEST OF THE CENTER. BASED ON THIS DATA THE DEPRESSION IS UPGRADED TO A 35-KT TROPICAL STORM... THE SECOND OF THE 2012 EAST PACIFIC HURRICANE SEASON. THE MODERATE EASTERLY SHEAR IS EXPECTED TO CONTINUE IN THE SHORT TERM WHICH SHOULD KEEP BUD FROM STRENGTHENING QUICKLY TODAY. BY TONIGHT...THE UPPER-LEVEL WIND PATTERN IS FORECAST TO BECOME MORE CONDUCIVE FOR STRENGTHENING AS AN UPPER-LEVEL ANTICYCLONE DEVELOPS NEAR OR JUST EAST OF BUD. NEARLY ALL OF THE INTENSITY GUIDANCE BRINGS BUD TO HURRICANE STRENGTH IN 36 TO 48 HOURS...AND SO DOES THE OFFICIAL FORECAST. LATER IN THE FORECAST PERIOD... INCREASING SHEAR AND SLIGHTLY COOLER SEA SURFACE TEMPERATURES ARE EXPECTED TO INDUCE SOME WEAKENING. THE OFFICIAL FORECAST IS A BLEND OF THE INTENSITY GUIDANCE THROUGH ABOUT 72 HOURS...BUT THE NHC FORECAST SHOWS LESS WEAKENING THAN THE STATISTICAL GUIDANCE AT 96 AND 120 HOURS. CENTER FIXES FROM THE LAST COUPLE OF ASCAT PASSES DURING THE PAST 12-18 HOURS SHOWS THAT BUD IS MOVING A LITTLE FASTER...295/10 KT. THE TROPICAL STORM IS FORECAST TO TURN TOWARD THE NORTHWEST LATER TODAY AS A WEAKNESS DEVELOPS IN THE SUBTROPICAL RIDGE. BUD IS EXPECTED TO TURN NORTHWARD IN ABOUT 36 HOURS AS A LONGWAVE TROUGH OVER THE WESTERN UNITED STATES DEEPENS. AFTER THAT TIME...THE TRACK FORECAST UNCERTAINTY INCREASES SIGNIFICANTLY AS THE SPREAD IN THE GUIDANCE AT 72 HOURS AND BEYOND BECOMES QUITE LARGE. THERE ARE BASICALLY TWO CAMPS OF MODELS IN THE LONG RANGE...THOSE THAT SHOW A DEEPER TROUGH WHICH CAUSES BUD TO ACCELERATE NORTHEASTWARD INTO MEXICO...AND A SECOND GROUP THAT TURNS BUD NORTHEASTWARD...BUT SHOWS THE CYCLONE DECELERATING AS IT NEARS SOUTHWESTERN MEXICO. FOR NOW THE OFFICIAL FORECAST LEANS TOWARD THE LATTER SOLUTION WHICH IS SUPPORTED BY THE TYPICALLY RELIABLE GFS AND ECMWF MODELS. WITH THE DEVELOPMENT OF BUD...THIS IS THE EARLIEST DATE ON RECORD FOR THE SECOND TROPICAL STORM FORMATION IN THE EAST PACIFIC. IT SURPASSES THE PREVIOUS EARLIEST DATE OF MAY 29. FORECAST POSITIONS AND MAX WINDS INIT 22/0900Z 10.4N 103.0W 35 KT 40 MPH 12H 22/1800Z 11.3N 104.2W 40 KT 45 MPH 24H 23/0600Z 12.4N 105.5W 50 KT 60 MPH 36H 23/1800Z 13.3N 106.3W 60 KT 70 MPH 48H 24/0600Z 14.3N 106.4W 75 KT 85 MPH 72H 25/0600Z 16.3N 105.3W 80 KT 90 MPH 96H 26/0600Z 17.5N 104.3W 60 KT 70 MPH 120H 27/0600Z 18.0N 104.0W 50 KT 60 MPH $$ FORECASTER BROWN