Tropical Storm BUD
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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
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